diff mbox

[v2,2/2] media: Add a driver for the ov7251 camera sensor

Message ID 1521778460-8717-3-git-send-email-todor.tomov@linaro.org (mailing list archive)
State New, archived
Headers show

Commit Message

Todor Tomov March 23, 2018, 4:14 a.m. UTC
The ov7251 sensor is a 1/7.5-Inch B&W VGA (640x480) CMOS Digital Image
Sensor from Omnivision.

The driver supports the following modes:
- 640x480 30fps
- 640x480 60fps
- 640x480 90fps

Output format is MIPI RAW 10.

The driver supports configuration via user controls for:
- exposure and gain;
- horizontal and vertical flip;
- test pattern.

Signed-off-by: Todor Tomov <todor.tomov@linaro.org>
---
 drivers/media/i2c/Kconfig  |   13 +
 drivers/media/i2c/Makefile |    1 +
 drivers/media/i2c/ov7251.c | 1494 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 1508 insertions(+)
 create mode 100644 drivers/media/i2c/ov7251.c

Comments

Jacopo Mondi March 23, 2018, 1:40 p.m. UTC | #1
Hi Todor,
   thanks for the patch.

When running checkpatch --strict I see a few warning you can easily
close (braces indentation mostly, and one additional empty line at
line 1048).

A few more nits below.

On Fri, Mar 23, 2018 at 12:14:20PM +0800, Todor Tomov wrote:
> The ov7251 sensor is a 1/7.5-Inch B&W VGA (640x480) CMOS Digital Image
> Sensor from Omnivision.
>
> The driver supports the following modes:
> - 640x480 30fps
> - 640x480 60fps
> - 640x480 90fps
>
> Output format is MIPI RAW 10.
>
> The driver supports configuration via user controls for:
> - exposure and gain;
> - horizontal and vertical flip;
> - test pattern.
>
> Signed-off-by: Todor Tomov <todor.tomov@linaro.org>
> ---
>  drivers/media/i2c/Kconfig  |   13 +
>  drivers/media/i2c/Makefile |    1 +
>  drivers/media/i2c/ov7251.c | 1494 ++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 1508 insertions(+)
>  create mode 100644 drivers/media/i2c/ov7251.c
>
> diff --git a/drivers/media/i2c/Kconfig b/drivers/media/i2c/Kconfig
> index 541f0d28..89aecb3 100644
> --- a/drivers/media/i2c/Kconfig
> +++ b/drivers/media/i2c/Kconfig
> @@ -688,6 +688,19 @@ config VIDEO_OV5695
>  	  To compile this driver as a module, choose M here: the
>  	  module will be called ov5695.
>
> +config VIDEO_OV7251
> +	tristate "OmniVision OV7251 sensor support"
> +	depends on OF
> +	depends on I2C && VIDEO_V4L2 && VIDEO_V4L2_SUBDEV_API
> +	depends on MEDIA_CAMERA_SUPPORT
> +	select V4L2_FWNODE
> +	---help---
> +	  This is a Video4Linux2 sensor-level driver for the OmniVision
> +	  OV7251 camera.
> +
> +	  To compile this driver as a module, choose M here: the
> +	  module will be called ov7251.
> +
>  config VIDEO_OV772X
>  	tristate "OmniVision OV772x sensor support"
>  	depends on I2C && VIDEO_V4L2
> diff --git a/drivers/media/i2c/Makefile b/drivers/media/i2c/Makefile
> index ea34aee..c8585b1 100644
> --- a/drivers/media/i2c/Makefile
> +++ b/drivers/media/i2c/Makefile
> @@ -70,6 +70,7 @@ obj-$(CONFIG_VIDEO_OV5647) += ov5647.o
>  obj-$(CONFIG_VIDEO_OV5670) += ov5670.o
>  obj-$(CONFIG_VIDEO_OV5695) += ov5695.o
>  obj-$(CONFIG_VIDEO_OV6650) += ov6650.o
> +obj-$(CONFIG_VIDEO_OV7251) += ov7251.o
>  obj-$(CONFIG_VIDEO_OV7640) += ov7640.o
>  obj-$(CONFIG_VIDEO_OV7670) += ov7670.o
>  obj-$(CONFIG_VIDEO_OV772X) += ov772x.o
> diff --git a/drivers/media/i2c/ov7251.c b/drivers/media/i2c/ov7251.c
> new file mode 100644
> index 0000000..7b401a9
> --- /dev/null
> +++ b/drivers/media/i2c/ov7251.c
> @@ -0,0 +1,1494 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Driver for the OV7251 camera sensor.
> + *
> + * Copyright (c) 2017-2018, The Linux Foundation. All rights reserved.
> + * Copyright (c) 2017-2018, Linaro Ltd.
> + */
> +
> +#include <linux/bitops.h>
> +#include <linux/clk.h>
> +#include <linux/delay.h>
> +#include <linux/device.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/i2c.h>
> +#include <linux/init.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_graph.h>
> +#include <linux/regulator/consumer.h>
> +#include <linux/slab.h>
> +#include <linux/types.h>
> +#include <media/v4l2-ctrls.h>
> +#include <media/v4l2-fwnode.h>
> +#include <media/v4l2-subdev.h>
> +
> +#define OV7251_VOLTAGE_ANALOG               2800000
> +#define OV7251_VOLTAGE_DIGITAL_CORE         1500000
> +#define OV7251_VOLTAGE_DIGITAL_IO           1800000
> +
> +#define OV7251_SC_MODE_SELECT		0x0100
> +#define OV7251_SC_MODE_SELECT_SW_STANDBY	0x0
> +#define OV7251_SC_MODE_SELECT_STREAMING		0x1
> +
> +#define OV7251_CHIP_ID_HIGH		0x300a
> +#define OV7251_CHIP_ID_HIGH_BYTE	0x77
> +#define OV7251_CHIP_ID_LOW		0x300b
> +#define OV7251_CHIP_ID_LOW_BYTE		0x50
> +#define OV7251_SC_GP_IO_IN1		0x3029
> +#define OV7251_AEC_EXPO_0		0x3500
> +#define OV7251_AEC_EXPO_1		0x3501
> +#define OV7251_AEC_EXPO_2		0x3502
> +#define OV7251_AEC_AGC_ADJ_0		0x350a
> +#define OV7251_AEC_AGC_ADJ_1		0x350b
> +#define OV7251_TIMING_FORMAT1		0x3820
> +#define OV7251_TIMING_FORMAT1_VFLIP	BIT(2)
> +#define OV7251_TIMING_FORMAT2		0x3821
> +#define OV7251_TIMING_FORMAT2_MIRROR	BIT(2)
> +#define OV7251_PRE_ISP_00		0x5e00
> +#define OV7251_PRE_ISP_00_TEST_PATTERN	BIT(7)
> +
> +struct reg_value {
> +	u16 reg;
> +	u8 val;
> +};
> +
> +struct ov7251_mode_info {
> +	u32 width;
> +	u32 height;
> +	const struct reg_value *data;
> +	u32 data_size;
> +	u32 pixel_clock;
> +	u32 link_freq;
> +	u16 exposure_max;
> +	u16 exposure_def;
> +	struct v4l2_fract timeperframe;
> +};
> +
> +struct ov7251 {
> +	struct i2c_client *i2c_client;
> +	struct device *dev;
> +	struct v4l2_subdev sd;
> +	struct media_pad pad;
> +	struct v4l2_fwnode_endpoint ep;
> +	struct v4l2_mbus_framefmt fmt;
> +	struct v4l2_rect crop;
> +	struct clk *xclk;
> +
> +	struct regulator *io_regulator;
> +	struct regulator *core_regulator;
> +	struct regulator *analog_regulator;
> +
> +	const struct ov7251_mode_info *current_mode;
> +
> +	struct v4l2_ctrl_handler ctrls;
> +	struct v4l2_ctrl *pixel_clock;
> +	struct v4l2_ctrl *link_freq;
> +	struct v4l2_ctrl *exposure;
> +	struct v4l2_ctrl *gain;
> +
> +	/* Cached register values */
> +	u8 aec_pk_manual;
> +	u8 pre_isp_00;
> +	u8 timing_format1;
> +	u8 timing_format2;
> +
> +	struct mutex power_lock; /* lock to protect power state */
> +	bool power_on;
> +
> +	struct gpio_desc *enable_gpio;
> +};
> +
> +static inline struct ov7251 *to_ov7251(struct v4l2_subdev *sd)
> +{
> +	return container_of(sd, struct ov7251, sd);
> +}
> +
> +static const struct reg_value ov7251_global_init_setting[] = {
> +	{ 0x0103, 0x01 },
> +	{ 0x303b, 0x02 },
> +};
> +
> +static const struct reg_value ov7251_setting_vga_30fps[] = {
> +	{ 0x3005, 0x00 },
> +	{ 0x3012, 0xc0 },
> +	{ 0x3013, 0xd2 },
> +	{ 0x3014, 0x04 },
> +	{ 0x3016, 0xf0 },
> +	{ 0x3017, 0xf0 },
> +	{ 0x3018, 0xf0 },
> +	{ 0x301a, 0xf0 },
> +	{ 0x301b, 0xf0 },
> +	{ 0x301c, 0xf0 },
> +	{ 0x3023, 0x05 },
> +	{ 0x3037, 0xf0 },
> +	{ 0x3098, 0x04 }, /* pll2 pre divider */
> +	{ 0x3099, 0x28 }, /* pll2 multiplier */
> +	{ 0x309a, 0x05 }, /* pll2 sys divider */
> +	{ 0x309b, 0x04 }, /* pll2 adc divider */
> +	{ 0x309d, 0x00 }, /* pll2 divider */
> +	{ 0x30b0, 0x0a }, /* pll1 pix divider */
> +	{ 0x30b1, 0x01 }, /* pll1 divider */
> +	{ 0x30b3, 0x64 }, /* pll1 multiplier */
> +	{ 0x30b4, 0x03 }, /* pll1 pre divider */
> +	{ 0x30b5, 0x05 }, /* pll1 mipi divider */
> +	{ 0x3106, 0xda },
> +	{ 0x3503, 0x07 },
> +	{ 0x3509, 0x10 },
> +	{ 0x3600, 0x1c },
> +	{ 0x3602, 0x62 },
> +	{ 0x3620, 0xb7 },
> +	{ 0x3622, 0x04 },
> +	{ 0x3626, 0x21 },
> +	{ 0x3627, 0x30 },
> +	{ 0x3630, 0x44 },
> +	{ 0x3631, 0x35 },
> +	{ 0x3634, 0x60 },
> +	{ 0x3636, 0x00 },
> +	{ 0x3662, 0x01 },
> +	{ 0x3663, 0x70 },
> +	{ 0x3664, 0x50 },
> +	{ 0x3666, 0x0a },
> +	{ 0x3669, 0x1a },
> +	{ 0x366a, 0x00 },
> +	{ 0x366b, 0x50 },
> +	{ 0x3673, 0x01 },
> +	{ 0x3674, 0xff },
> +	{ 0x3675, 0x03 },
> +	{ 0x3705, 0xc1 },
> +	{ 0x3709, 0x40 },
> +	{ 0x373c, 0x08 },
> +	{ 0x3742, 0x00 },
> +	{ 0x3757, 0xb3 },
> +	{ 0x3788, 0x00 },
> +	{ 0x37a8, 0x01 },
> +	{ 0x37a9, 0xc0 },
> +	{ 0x3800, 0x00 },
> +	{ 0x3801, 0x04 },
> +	{ 0x3802, 0x00 },
> +	{ 0x3803, 0x04 },
> +	{ 0x3804, 0x02 },
> +	{ 0x3805, 0x8b },
> +	{ 0x3806, 0x01 },
> +	{ 0x3807, 0xeb },
> +	{ 0x3808, 0x02 }, /* width high */
> +	{ 0x3809, 0x80 }, /* width low */
> +	{ 0x380a, 0x01 }, /* height high */
> +	{ 0x380b, 0xe0 }, /* height low */
> +	{ 0x380c, 0x03 }, /* total horiz timing high */
> +	{ 0x380d, 0xa0 }, /* total horiz timing low */
> +	{ 0x380e, 0x06 }, /* total vertical timing high */
> +	{ 0x380f, 0xbc }, /* total vertical timing low */
> +	{ 0x3810, 0x00 },
> +	{ 0x3811, 0x04 },
> +	{ 0x3812, 0x00 },
> +	{ 0x3813, 0x05 },
> +	{ 0x3814, 0x11 },
> +	{ 0x3815, 0x11 },
> +	{ 0x3820, 0x40 },
> +	{ 0x3821, 0x00 },
> +	{ 0x382f, 0x0e },
> +	{ 0x3832, 0x00 },
> +	{ 0x3833, 0x05 },
> +	{ 0x3834, 0x00 },
> +	{ 0x3835, 0x0c },
> +	{ 0x3837, 0x00 },
> +	{ 0x3b80, 0x00 },
> +	{ 0x3b81, 0xa5 },
> +	{ 0x3b82, 0x10 },
> +	{ 0x3b83, 0x00 },
> +	{ 0x3b84, 0x08 },
> +	{ 0x3b85, 0x00 },
> +	{ 0x3b86, 0x01 },
> +	{ 0x3b87, 0x00 },
> +	{ 0x3b88, 0x00 },
> +	{ 0x3b89, 0x00 },
> +	{ 0x3b8a, 0x00 },
> +	{ 0x3b8b, 0x05 },
> +	{ 0x3b8c, 0x00 },
> +	{ 0x3b8d, 0x00 },
> +	{ 0x3b8e, 0x00 },
> +	{ 0x3b8f, 0x1a },
> +	{ 0x3b94, 0x05 },
> +	{ 0x3b95, 0xf2 },
> +	{ 0x3b96, 0x40 },
> +	{ 0x3c00, 0x89 },
> +	{ 0x3c01, 0x63 },
> +	{ 0x3c02, 0x01 },
> +	{ 0x3c03, 0x00 },
> +	{ 0x3c04, 0x00 },
> +	{ 0x3c05, 0x03 },
> +	{ 0x3c06, 0x00 },
> +	{ 0x3c07, 0x06 },
> +	{ 0x3c0c, 0x01 },
> +	{ 0x3c0d, 0xd0 },
> +	{ 0x3c0e, 0x02 },
> +	{ 0x3c0f, 0x0a },
> +	{ 0x4001, 0x42 },
> +	{ 0x4004, 0x04 },
> +	{ 0x4005, 0x00 },
> +	{ 0x404e, 0x01 },
> +	{ 0x4300, 0xff },
> +	{ 0x4301, 0x00 },
> +	{ 0x4315, 0x00 },
> +	{ 0x4501, 0x48 },
> +	{ 0x4600, 0x00 },
> +	{ 0x4601, 0x4e },
> +	{ 0x4801, 0x0f },
> +	{ 0x4806, 0x0f },
> +	{ 0x4819, 0xaa },
> +	{ 0x4823, 0x3e },
> +	{ 0x4837, 0x19 },
> +	{ 0x4a0d, 0x00 },
> +	{ 0x4a47, 0x7f },
> +	{ 0x4a49, 0xf0 },
> +	{ 0x4a4b, 0x30 },
> +	{ 0x5000, 0x85 },
> +	{ 0x5001, 0x80 },
> +};
> +
> +static const struct reg_value ov7251_setting_vga_60fps[] = {
> +	{ 0x3005, 0x00 },
> +	{ 0x3012, 0xc0 },
> +	{ 0x3013, 0xd2 },
> +	{ 0x3014, 0x04 },
> +	{ 0x3016, 0x10 },
> +	{ 0x3017, 0x00 },
> +	{ 0x3018, 0x00 },
> +	{ 0x301a, 0x00 },
> +	{ 0x301b, 0x00 },
> +	{ 0x301c, 0x00 },
> +	{ 0x3023, 0x05 },
> +	{ 0x3037, 0xf0 },
> +	{ 0x3098, 0x04 }, /* pll2 pre divider */
> +	{ 0x3099, 0x28 }, /* pll2 multiplier */
> +	{ 0x309a, 0x05 }, /* pll2 sys divider */
> +	{ 0x309b, 0x04 }, /* pll2 adc divider */
> +	{ 0x309d, 0x00 }, /* pll2 divider */
> +	{ 0x30b0, 0x0a }, /* pll1 pix divider */
> +	{ 0x30b1, 0x01 }, /* pll1 divider */
> +	{ 0x30b3, 0x64 }, /* pll1 multiplier */
> +	{ 0x30b4, 0x03 }, /* pll1 pre divider */
> +	{ 0x30b5, 0x05 }, /* pll1 mipi divider */
> +	{ 0x3106, 0xda },
> +	{ 0x3503, 0x07 },
> +	{ 0x3509, 0x10 },
> +	{ 0x3600, 0x1c },
> +	{ 0x3602, 0x62 },
> +	{ 0x3620, 0xb7 },
> +	{ 0x3622, 0x04 },
> +	{ 0x3626, 0x21 },
> +	{ 0x3627, 0x30 },
> +	{ 0x3630, 0x44 },
> +	{ 0x3631, 0x35 },
> +	{ 0x3634, 0x60 },
> +	{ 0x3636, 0x00 },
> +	{ 0x3662, 0x01 },
> +	{ 0x3663, 0x70 },
> +	{ 0x3664, 0x50 },
> +	{ 0x3666, 0x0a },
> +	{ 0x3669, 0x1a },
> +	{ 0x366a, 0x00 },
> +	{ 0x366b, 0x50 },
> +	{ 0x3673, 0x01 },
> +	{ 0x3674, 0xff },
> +	{ 0x3675, 0x03 },
> +	{ 0x3705, 0xc1 },
> +	{ 0x3709, 0x40 },
> +	{ 0x373c, 0x08 },
> +	{ 0x3742, 0x00 },
> +	{ 0x3757, 0xb3 },
> +	{ 0x3788, 0x00 },
> +	{ 0x37a8, 0x01 },
> +	{ 0x37a9, 0xc0 },
> +	{ 0x3800, 0x00 },
> +	{ 0x3801, 0x04 },
> +	{ 0x3802, 0x00 },
> +	{ 0x3803, 0x04 },
> +	{ 0x3804, 0x02 },
> +	{ 0x3805, 0x8b },
> +	{ 0x3806, 0x01 },
> +	{ 0x3807, 0xeb },
> +	{ 0x3808, 0x02 }, /* width high */
> +	{ 0x3809, 0x80 }, /* width low */
> +	{ 0x380a, 0x01 }, /* height high */
> +	{ 0x380b, 0xe0 }, /* height low */
> +	{ 0x380c, 0x03 }, /* total horiz timing high */
> +	{ 0x380d, 0xa0 }, /* total horiz timing low */
> +	{ 0x380e, 0x03 }, /* total vertical timing high */
> +	{ 0x380f, 0x5c }, /* total vertical timing low */
> +	{ 0x3810, 0x00 },
> +	{ 0x3811, 0x04 },
> +	{ 0x3812, 0x00 },
> +	{ 0x3813, 0x05 },
> +	{ 0x3814, 0x11 },
> +	{ 0x3815, 0x11 },
> +	{ 0x3820, 0x40 },
> +	{ 0x3821, 0x00 },
> +	{ 0x382f, 0x0e },
> +	{ 0x3832, 0x00 },
> +	{ 0x3833, 0x05 },
> +	{ 0x3834, 0x00 },
> +	{ 0x3835, 0x0c },
> +	{ 0x3837, 0x00 },
> +	{ 0x3b80, 0x00 },
> +	{ 0x3b81, 0xa5 },
> +	{ 0x3b82, 0x10 },
> +	{ 0x3b83, 0x00 },
> +	{ 0x3b84, 0x08 },
> +	{ 0x3b85, 0x00 },
> +	{ 0x3b86, 0x01 },
> +	{ 0x3b87, 0x00 },
> +	{ 0x3b88, 0x00 },
> +	{ 0x3b89, 0x00 },
> +	{ 0x3b8a, 0x00 },
> +	{ 0x3b8b, 0x05 },
> +	{ 0x3b8c, 0x00 },
> +	{ 0x3b8d, 0x00 },
> +	{ 0x3b8e, 0x00 },
> +	{ 0x3b8f, 0x1a },
> +	{ 0x3b94, 0x05 },
> +	{ 0x3b95, 0xf2 },
> +	{ 0x3b96, 0x40 },
> +	{ 0x3c00, 0x89 },
> +	{ 0x3c01, 0x63 },
> +	{ 0x3c02, 0x01 },
> +	{ 0x3c03, 0x00 },
> +	{ 0x3c04, 0x00 },
> +	{ 0x3c05, 0x03 },
> +	{ 0x3c06, 0x00 },
> +	{ 0x3c07, 0x06 },
> +	{ 0x3c0c, 0x01 },
> +	{ 0x3c0d, 0xd0 },
> +	{ 0x3c0e, 0x02 },
> +	{ 0x3c0f, 0x0a },
> +	{ 0x4001, 0x42 },
> +	{ 0x4004, 0x04 },
> +	{ 0x4005, 0x00 },
> +	{ 0x404e, 0x01 },
> +	{ 0x4300, 0xff },
> +	{ 0x4301, 0x00 },
> +	{ 0x4315, 0x00 },
> +	{ 0x4501, 0x48 },
> +	{ 0x4600, 0x00 },
> +	{ 0x4601, 0x4e },
> +	{ 0x4801, 0x0f },
> +	{ 0x4806, 0x0f },
> +	{ 0x4819, 0xaa },
> +	{ 0x4823, 0x3e },
> +	{ 0x4837, 0x19 },
> +	{ 0x4a0d, 0x00 },
> +	{ 0x4a47, 0x7f },
> +	{ 0x4a49, 0xf0 },
> +	{ 0x4a4b, 0x30 },
> +	{ 0x5000, 0x85 },
> +	{ 0x5001, 0x80 },
> +};
> +
> +static const struct reg_value ov7251_setting_vga_90fps[] = {
> +	{ 0x3005, 0x00 },
> +	{ 0x3012, 0xc0 },
> +	{ 0x3013, 0xd2 },
> +	{ 0x3014, 0x04 },
> +	{ 0x3016, 0x10 },
> +	{ 0x3017, 0x00 },
> +	{ 0x3018, 0x00 },
> +	{ 0x301a, 0x00 },
> +	{ 0x301b, 0x00 },
> +	{ 0x301c, 0x00 },
> +	{ 0x3023, 0x05 },
> +	{ 0x3037, 0xf0 },
> +	{ 0x3098, 0x04 }, /* pll2 pre divider */
> +	{ 0x3099, 0x28 }, /* pll2 multiplier */
> +	{ 0x309a, 0x05 }, /* pll2 sys divider */
> +	{ 0x309b, 0x04 }, /* pll2 adc divider */
> +	{ 0x309d, 0x00 }, /* pll2 divider */
> +	{ 0x30b0, 0x0a }, /* pll1 pix divider */
> +	{ 0x30b1, 0x01 }, /* pll1 divider */
> +	{ 0x30b3, 0x64 }, /* pll1 multiplier */
> +	{ 0x30b4, 0x03 }, /* pll1 pre divider */
> +	{ 0x30b5, 0x05 }, /* pll1 mipi divider */
> +	{ 0x3106, 0xda },
> +	{ 0x3503, 0x07 },
> +	{ 0x3509, 0x10 },
> +	{ 0x3600, 0x1c },
> +	{ 0x3602, 0x62 },
> +	{ 0x3620, 0xb7 },
> +	{ 0x3622, 0x04 },
> +	{ 0x3626, 0x21 },
> +	{ 0x3627, 0x30 },
> +	{ 0x3630, 0x44 },
> +	{ 0x3631, 0x35 },
> +	{ 0x3634, 0x60 },
> +	{ 0x3636, 0x00 },
> +	{ 0x3662, 0x01 },
> +	{ 0x3663, 0x70 },
> +	{ 0x3664, 0x50 },
> +	{ 0x3666, 0x0a },
> +	{ 0x3669, 0x1a },
> +	{ 0x366a, 0x00 },
> +	{ 0x366b, 0x50 },
> +	{ 0x3673, 0x01 },
> +	{ 0x3674, 0xff },
> +	{ 0x3675, 0x03 },
> +	{ 0x3705, 0xc1 },
> +	{ 0x3709, 0x40 },
> +	{ 0x373c, 0x08 },
> +	{ 0x3742, 0x00 },
> +	{ 0x3757, 0xb3 },
> +	{ 0x3788, 0x00 },
> +	{ 0x37a8, 0x01 },
> +	{ 0x37a9, 0xc0 },
> +	{ 0x3800, 0x00 },
> +	{ 0x3801, 0x04 },
> +	{ 0x3802, 0x00 },
> +	{ 0x3803, 0x04 },
> +	{ 0x3804, 0x02 },
> +	{ 0x3805, 0x8b },
> +	{ 0x3806, 0x01 },
> +	{ 0x3807, 0xeb },
> +	{ 0x3808, 0x02 }, /* width high */
> +	{ 0x3809, 0x80 }, /* width low */
> +	{ 0x380a, 0x01 }, /* height high */
> +	{ 0x380b, 0xe0 }, /* height low */
> +	{ 0x380c, 0x03 }, /* total horiz timing high */
> +	{ 0x380d, 0xa0 }, /* total horiz timing low */
> +	{ 0x380e, 0x02 }, /* total vertical timing high */
> +	{ 0x380f, 0x3c }, /* total vertical timing low */
> +	{ 0x3810, 0x00 },
> +	{ 0x3811, 0x04 },
> +	{ 0x3812, 0x00 },
> +	{ 0x3813, 0x05 },
> +	{ 0x3814, 0x11 },
> +	{ 0x3815, 0x11 },
> +	{ 0x3820, 0x40 },
> +	{ 0x3821, 0x00 },
> +	{ 0x382f, 0x0e },
> +	{ 0x3832, 0x00 },
> +	{ 0x3833, 0x05 },
> +	{ 0x3834, 0x00 },
> +	{ 0x3835, 0x0c },
> +	{ 0x3837, 0x00 },
> +	{ 0x3b80, 0x00 },
> +	{ 0x3b81, 0xa5 },
> +	{ 0x3b82, 0x10 },
> +	{ 0x3b83, 0x00 },
> +	{ 0x3b84, 0x08 },
> +	{ 0x3b85, 0x00 },
> +	{ 0x3b86, 0x01 },
> +	{ 0x3b87, 0x00 },
> +	{ 0x3b88, 0x00 },
> +	{ 0x3b89, 0x00 },
> +	{ 0x3b8a, 0x00 },
> +	{ 0x3b8b, 0x05 },
> +	{ 0x3b8c, 0x00 },
> +	{ 0x3b8d, 0x00 },
> +	{ 0x3b8e, 0x00 },
> +	{ 0x3b8f, 0x1a },
> +	{ 0x3b94, 0x05 },
> +	{ 0x3b95, 0xf2 },
> +	{ 0x3b96, 0x40 },
> +	{ 0x3c00, 0x89 },
> +	{ 0x3c01, 0x63 },
> +	{ 0x3c02, 0x01 },
> +	{ 0x3c03, 0x00 },
> +	{ 0x3c04, 0x00 },
> +	{ 0x3c05, 0x03 },
> +	{ 0x3c06, 0x00 },
> +	{ 0x3c07, 0x06 },
> +	{ 0x3c0c, 0x01 },
> +	{ 0x3c0d, 0xd0 },
> +	{ 0x3c0e, 0x02 },
> +	{ 0x3c0f, 0x0a },
> +	{ 0x4001, 0x42 },
> +	{ 0x4004, 0x04 },
> +	{ 0x4005, 0x00 },
> +	{ 0x404e, 0x01 },
> +	{ 0x4300, 0xff },
> +	{ 0x4301, 0x00 },
> +	{ 0x4315, 0x00 },
> +	{ 0x4501, 0x48 },
> +	{ 0x4600, 0x00 },
> +	{ 0x4601, 0x4e },
> +	{ 0x4801, 0x0f },
> +	{ 0x4806, 0x0f },
> +	{ 0x4819, 0xaa },
> +	{ 0x4823, 0x3e },
> +	{ 0x4837, 0x19 },
> +	{ 0x4a0d, 0x00 },
> +	{ 0x4a47, 0x7f },
> +	{ 0x4a49, 0xf0 },
> +	{ 0x4a4b, 0x30 },
> +	{ 0x5000, 0x85 },
> +	{ 0x5001, 0x80 },
> +};
> +
> +static const s64 link_freq[] = {
> +	240000000,
> +};
> +
> +static const struct ov7251_mode_info ov7251_mode_info_data[] = {
> +	{
> +		.width = 640,
> +		.height = 480,
> +		.data = ov7251_setting_vga_30fps,
> +		.data_size = ARRAY_SIZE(ov7251_setting_vga_30fps),
> +		.pixel_clock = 48000000,
> +		.link_freq = 0, /* an index in link_freq[] */
> +		.exposure_max = 1704,
> +		.exposure_def = 504,
> +		.timeperframe = {
> +			.numerator = 100,
> +			.denominator = 3000
> +		}
> +	},
> +	{
> +		.width = 640,
> +		.height = 480,
> +		.data = ov7251_setting_vga_60fps,
> +		.data_size = ARRAY_SIZE(ov7251_setting_vga_60fps),
> +		.pixel_clock = 48000000,
> +		.link_freq = 0, /* an index in link_freq[] */
> +		.exposure_max = 840,
> +		.exposure_def = 504,
> +		.timeperframe = {
> +			.numerator = 100,
> +			.denominator = 6014
> +		}
> +	},
> +	{
> +		.width = 640,
> +		.height = 480,
> +		.data = ov7251_setting_vga_90fps,
> +		.data_size = ARRAY_SIZE(ov7251_setting_vga_90fps),
> +		.pixel_clock = 48000000,
> +		.link_freq = 0, /* an index in link_freq[] */
> +		.exposure_max = 552,
> +		.exposure_def = 504,
> +		.timeperframe = {
> +			.numerator = 100,
> +			.denominator = 9043
> +		}
> +	},
> +};
> +
> +static int ov7251_regulators_enable(struct ov7251 *ov7251)
> +{
> +	int ret;
> +
> +	ret = regulator_enable(ov7251->io_regulator);
> +	if (ret < 0) {
> +		dev_err(ov7251->dev, "set io voltage failed\n");
> +		return ret;
> +	}
> +
> +	ret = regulator_enable(ov7251->analog_regulator);
> +	if (ret) {
> +		dev_err(ov7251->dev, "set analog voltage failed\n");
> +		goto err_disable_io;
> +	}
> +
> +	ret = regulator_enable(ov7251->core_regulator);
> +	if (ret) {
> +		dev_err(ov7251->dev, "set core voltage failed\n");
> +		goto err_disable_analog;
> +	}
> +
> +	return 0;
> +
> +err_disable_analog:
> +	regulator_disable(ov7251->analog_regulator);
> +err_disable_io:
> +	regulator_disable(ov7251->io_regulator);
> +
> +	return ret;
> +}
> +
> +static void ov7251_regulators_disable(struct ov7251 *ov7251)
> +{
> +	int ret;
> +
> +	ret = regulator_disable(ov7251->core_regulator);
> +	if (ret < 0)
> +		dev_err(ov7251->dev, "core regulator disable failed\n");
> +
> +	ret = regulator_disable(ov7251->analog_regulator);
> +	if (ret < 0)
> +		dev_err(ov7251->dev, "analog regulator disable failed\n");
> +
> +	ret = regulator_disable(ov7251->io_regulator);
> +	if (ret < 0)
> +		dev_err(ov7251->dev, "io regulator disable failed\n");
> +}
> +
> +static int ov7251_write_reg(struct ov7251 *ov7251, u16 reg, u8 val)
> +{
> +	u8 regbuf[3];
> +	int ret;
> +
> +	regbuf[0] = reg >> 8;
> +	regbuf[1] = reg & 0xff;
> +	regbuf[2] = val;
> +
> +	ret = i2c_master_send(ov7251->i2c_client, regbuf, 3);
> +	if (ret < 0) {
> +		dev_err(ov7251->dev, "%s: write reg error %d: reg=%x, val=%x\n",
> +			__func__, ret, reg, val);
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static int ov7251_read_reg(struct ov7251 *ov7251, u16 reg, u8 *val)
> +{
> +	u8 regbuf[2];
> +	int ret;
> +
> +	regbuf[0] = reg >> 8;
> +	regbuf[1] = reg & 0xff;
> +
> +	ret = i2c_master_send(ov7251->i2c_client, regbuf, 2);
> +	if (ret < 0) {
> +		dev_err(ov7251->dev, "%s: write reg error %d: reg=%x\n",
> +			__func__, ret, reg);
> +		return ret;
> +	}
> +
> +	ret = i2c_master_recv(ov7251->i2c_client, val, 1);
> +	if (ret < 0) {
> +		dev_err(ov7251->dev, "%s: read reg error %d: reg=%x\n",
> +			__func__, ret, reg);
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static int ov7251_set_exposure(struct ov7251 *ov7251, s32 exposure)
> +{
> +	int ret;
> +
> +	ret = ov7251_write_reg(ov7251, OV7251_AEC_EXPO_0,
> +			       (exposure & 0xf000) >> 12);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = ov7251_write_reg(ov7251, OV7251_AEC_EXPO_1,
> +			       (exposure & 0x0ff0) >> 4);
> +	if (ret < 0)
> +		return ret;
> +
> +	return ov7251_write_reg(ov7251, OV7251_AEC_EXPO_2,
> +				(exposure & 0x000f) << 4);
> +}
> +
> +static int ov7251_set_gain(struct ov7251 *ov7251, s32 gain)
> +{
> +	int ret;
> +
> +	ret = ov7251_write_reg(ov7251, OV7251_AEC_AGC_ADJ_0,
> +			       (gain & 0x0300) >> 8);
> +	if (ret < 0)
> +		return ret;
> +
> +	return ov7251_write_reg(ov7251, OV7251_AEC_AGC_ADJ_1, gain & 0xff);
> +}
> +
> +static int ov7251_set_register_array(struct ov7251 *ov7251,
> +				     const struct reg_value *settings,
> +				     unsigned int num_settings)
> +{
> +	unsigned int i;
> +	int ret;
> +
> +	for (i = 0; i < num_settings; ++i, ++settings) {
> +		ret = ov7251_write_reg(ov7251, settings->reg, settings->val);
> +		if (ret < 0)
> +			return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static int ov7251_set_power_on(struct ov7251 *ov7251)
> +{
> +	int ret;
> +
> +	ret = ov7251_regulators_enable(ov7251);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = clk_prepare_enable(ov7251->xclk);
> +	if (ret < 0) {
> +		dev_err(ov7251->dev, "clk prepare enable failed\n");
> +		ov7251_regulators_disable(ov7251);
> +		return ret;
> +	}
> +
> +	gpiod_set_value_cansleep(ov7251->enable_gpio, 1);
> +
> +	usleep_range(3000, 4000); /* 65536 / 24MHz = 2.73ms */
> +
> +	return 0;
> +}
> +
> +static void ov7251_set_power_off(struct ov7251 *ov7251)
> +{
> +	clk_disable_unprepare(ov7251->xclk);
> +	gpiod_set_value_cansleep(ov7251->enable_gpio, 0);
> +	ov7251_regulators_disable(ov7251);
> +}
> +
> +static int ov7251_s_power(struct v4l2_subdev *sd, int on)
> +{
> +	struct ov7251 *ov7251 = to_ov7251(sd);
> +	int ret = 0;
> +
> +	mutex_lock(&ov7251->power_lock);
> +
> +	/*
> +	 * If the power state is modified from 0 to 1 or from 1 to 0,
> +	 * update the power state.
> +	 */
> +	if (ov7251->power_on == !on) {

        if (ov7251->power_on == !!on) {
                mutex_unlock(&ov7251->power_lock);
                return 0;
        }

And you can save one indentation level and remove ret initialization.


> +		if (on) {
> +			ret = ov7251_set_power_on(ov7251);
> +			if (ret < 0)
> +				goto exit;
> +
> +			ret = ov7251_set_register_array(ov7251,
> +					ov7251_global_init_setting,
> +					ARRAY_SIZE(ov7251_global_init_setting));
> +			if (ret < 0) {
> +				dev_err(ov7251->dev,
> +					"could not set init registers\n");
> +				ov7251_set_power_off(ov7251);
> +				goto exit;
> +			}
> +
> +			ov7251->power_on = true;
> +		} else {
> +			ov7251_set_power_off(ov7251);
> +			ov7251->power_on = false;
> +		}
> +	}
> +
> +exit:
> +	mutex_unlock(&ov7251->power_lock);
> +
> +	return ret;
> +}
> +
> +static int ov7251_set_hflip(struct ov7251 *ov7251, s32 value)
> +{
> +	u8 val = ov7251->timing_format2;
> +	int ret;
> +
> +	if (value)
> +		val |= OV7251_TIMING_FORMAT2_MIRROR;
> +	else
> +		val &= ~OV7251_TIMING_FORMAT2_MIRROR;
> +
> +	ret = ov7251_write_reg(ov7251, OV7251_TIMING_FORMAT2, val);
> +	if (!ret)
> +		ov7251->timing_format2 = val;
> +
> +	return ret;
> +}
> +
> +static int ov7251_set_vflip(struct ov7251 *ov7251, s32 value)
> +{
> +	u8 val = ov7251->timing_format1;
> +	int ret;
> +
> +	if (value)
> +		val |= OV7251_TIMING_FORMAT1_VFLIP;
> +	else
> +		val &= ~OV7251_TIMING_FORMAT1_VFLIP;
> +
> +	ret = ov7251_write_reg(ov7251, OV7251_TIMING_FORMAT1, val);
> +	if (!ret)
> +		ov7251->timing_format1 = val;
> +
> +	return ret;
> +}
> +
> +static int ov7251_set_test_pattern(struct ov7251 *ov7251, s32 value)
> +{
> +	u8 val = ov7251->pre_isp_00;
> +	int ret;
> +
> +	if (value)
> +		val |= OV7251_PRE_ISP_00_TEST_PATTERN;
> +	else
> +		val &= ~OV7251_PRE_ISP_00_TEST_PATTERN;
> +
> +	ret = ov7251_write_reg(ov7251, OV7251_PRE_ISP_00, val);
> +	if (!ret)
> +		ov7251->pre_isp_00 = val;
> +
> +	return ret;
> +}
> +
> +static const char * const ov7251_test_pattern_menu[] = {
> +	"Disabled",
> +	"Vertical Pattern Bars",
> +};
> +
> +static int ov7251_s_ctrl(struct v4l2_ctrl *ctrl)
> +{
> +	struct ov7251 *ov7251 = container_of(ctrl->handler,
> +					     struct ov7251, ctrls);
> +	int ret;
> +
> +	mutex_lock(&ov7251->power_lock);
> +	if (!ov7251->power_on) {
> +		mutex_unlock(&ov7251->power_lock);
> +		return 0;
> +	}
> +
> +	switch (ctrl->id) {
> +	case V4L2_CID_EXPOSURE:
> +		ret = ov7251_set_exposure(ov7251, ctrl->val);
> +		break;
> +	case V4L2_CID_GAIN:
> +		ret = ov7251_set_gain(ov7251, ctrl->val);
> +		break;
> +	case V4L2_CID_TEST_PATTERN:
> +		ret = ov7251_set_test_pattern(ov7251, ctrl->val);
> +		break;
> +	case V4L2_CID_HFLIP:
> +		ret = ov7251_set_hflip(ov7251, ctrl->val);
> +		break;
> +	case V4L2_CID_VFLIP:
> +		ret = ov7251_set_vflip(ov7251, ctrl->val);
> +		break;
> +	default:
> +		ret = -EINVAL;
> +		break;
> +	}
> +
> +	mutex_unlock(&ov7251->power_lock);
> +
> +	return ret;
> +}
> +
> +static const struct v4l2_ctrl_ops ov7251_ctrl_ops = {
> +	.s_ctrl = ov7251_s_ctrl,
> +};
> +
> +static int ov7251_enum_mbus_code(struct v4l2_subdev *sd,
> +				 struct v4l2_subdev_pad_config *cfg,
> +				 struct v4l2_subdev_mbus_code_enum *code)
> +{
> +	if (code->index > 0)
> +		return -EINVAL;
> +
> +	code->code = MEDIA_BUS_FMT_SBGGR10_1X10;
> +
> +	return 0;
> +}
> +
> +static int ov7251_enum_frame_size(struct v4l2_subdev *subdev,
> +				  struct v4l2_subdev_pad_config *cfg,
> +				  struct v4l2_subdev_frame_size_enum *fse)
> +{

Shouldn't you check for (pad != 0) in all subdev pad operations?
I see other driver with a single pad doing this...


> +	if (fse->code != MEDIA_BUS_FMT_SBGGR10_1X10)
> +		return -EINVAL;
> +
> +	if (fse->index >= ARRAY_SIZE(ov7251_mode_info_data))
> +		return -EINVAL;
> +
> +	fse->min_width = ov7251_mode_info_data[fse->index].width;
> +	fse->max_width = ov7251_mode_info_data[fse->index].width;
> +	fse->min_height = ov7251_mode_info_data[fse->index].height;
> +	fse->max_height = ov7251_mode_info_data[fse->index].height;
> +
> +	return 0;
> +}
> +
> +static int ov7251_enum_frame_ival(struct v4l2_subdev *subdev,
> +				  struct v4l2_subdev_pad_config *cfg,
> +				  struct v4l2_subdev_frame_interval_enum *fie)
> +{
> +	int index = fie->index;
> +	int i;
> +
> +	for (i = 0; i < ARRAY_SIZE(ov7251_mode_info_data); i++) {
> +		if (fie->width != ov7251_mode_info_data[i].width ||
> +		    fie->height != ov7251_mode_info_data[i].height)
> +			continue;
> +
> +		if (index-- == 0) {
> +			fie->interval = ov7251_mode_info_data[i].timeperframe;
> +			return 0;
> +		}
> +	}
> +
> +	return -EINVAL;
> +}
> +
> +static struct v4l2_mbus_framefmt *
> +__ov7251_get_pad_format(struct ov7251 *ov7251,
> +			struct v4l2_subdev_pad_config *cfg,
> +			unsigned int pad,
> +			enum v4l2_subdev_format_whence which)
> +{
> +	switch (which) {
> +	case V4L2_SUBDEV_FORMAT_TRY:
> +		return v4l2_subdev_get_try_format(&ov7251->sd, cfg, pad);
> +	case V4L2_SUBDEV_FORMAT_ACTIVE:
> +		return &ov7251->fmt;
> +	default:
> +		return NULL;
> +	}
> +}
> +
> +static int ov7251_get_format(struct v4l2_subdev *sd,
> +			     struct v4l2_subdev_pad_config *cfg,
> +			     struct v4l2_subdev_format *format)
> +{
> +	struct ov7251 *ov7251 = to_ov7251(sd);
> +
> +	format->format = *__ov7251_get_pad_format(ov7251, cfg, format->pad,
> +						  format->which);
> +	return 0;
> +}
> +
> +static struct v4l2_rect *
> +__ov7251_get_pad_crop(struct ov7251 *ov7251, struct v4l2_subdev_pad_config *cfg,
> +		      unsigned int pad, enum v4l2_subdev_format_whence which)
> +{
> +	switch (which) {
> +	case V4L2_SUBDEV_FORMAT_TRY:
> +		return v4l2_subdev_get_try_crop(&ov7251->sd, cfg, pad);
> +	case V4L2_SUBDEV_FORMAT_ACTIVE:
> +		return &ov7251->crop;
> +	default:
> +		return NULL;
> +	}
> +}
> +
> +#define TIMEPERFRAME_AVG_FPS(t)						\
> +	(((t).denominator + ((t).numerator >> 1)) / (t).numerator)
> +
> +static const struct ov7251_mode_info *
> +ov7251_find_mode_by_ival(struct ov7251 *ov7251, struct v4l2_fract *timeperframe)
> +{
> +	const struct ov7251_mode_info *mode = ov7251->current_mode;
> +	int fps_req = TIMEPERFRAME_AVG_FPS(*timeperframe);
> +	unsigned int max_dist_match = (unsigned int) -1;
> +	int i, n = 0;
> +
> +	for (i = 0; i < ARRAY_SIZE(ov7251_mode_info_data); i++) {
> +		unsigned int dist;
> +		int fps_tmp;
> +
> +		if (mode->width != ov7251_mode_info_data[i].width ||
> +		    mode->height != ov7251_mode_info_data[i].height)
> +			continue;
> +
> +		fps_tmp = TIMEPERFRAME_AVG_FPS(
> +					ov7251_mode_info_data[i].timeperframe);
> +
> +		dist = abs(fps_req - fps_tmp);
> +
> +		if (dist < max_dist_match) {
> +			n = i;
> +			max_dist_match = dist;
> +		}
> +	}
> +
> +	return &ov7251_mode_info_data[n];
> +}
> +
> +static int ov7251_set_format(struct v4l2_subdev *sd,
> +			     struct v4l2_subdev_pad_config *cfg,
> +			     struct v4l2_subdev_format *format)
> +{
> +	struct ov7251 *ov7251 = to_ov7251(sd);
> +	struct v4l2_mbus_framefmt *__format;
> +	struct v4l2_rect *__crop;
> +	const struct ov7251_mode_info *new_mode;
> +	int ret;
> +
> +	__crop = __ov7251_get_pad_crop(ov7251, cfg, format->pad,
> +			format->which);
> +
> +	new_mode = v4l2_find_nearest_size(ov7251_mode_info_data,
> +			       width, height,
> +			       format->format.width, format->format.height);
> +
> +	__crop->width = new_mode->width;
> +	__crop->height = new_mode->height;
> +
> +	if (format->which == V4L2_SUBDEV_FORMAT_ACTIVE) {
> +		ret = v4l2_ctrl_s_ctrl_int64(ov7251->pixel_clock,
> +					     new_mode->pixel_clock);
> +		if (ret < 0)
> +			return ret;
> +
> +		ret = v4l2_ctrl_s_ctrl(ov7251->link_freq,
> +				       new_mode->link_freq);
> +		if (ret < 0)
> +			return ret;
> +
> +		ret = v4l2_ctrl_modify_range(ov7251->exposure,
> +					     1, new_mode->exposure_max,
> +					     1, new_mode->exposure_def);
> +		if (ret < 0)
> +			return ret;
> +
> +		ret = v4l2_ctrl_s_ctrl(ov7251->exposure,
> +				       new_mode->exposure_def);
> +		if (ret < 0)
> +			return ret;
> +
> +
> +		ret = v4l2_ctrl_s_ctrl(ov7251->gain, 16);
> +		if (ret < 0)
> +			return ret;
> +
> +		ov7251->current_mode = new_mode;
> +	}
> +
> +	__format = __ov7251_get_pad_format(ov7251, cfg, format->pad,
> +			format->which);
> +	__format->width = __crop->width;
> +	__format->height = __crop->height;
> +	__format->code = MEDIA_BUS_FMT_SBGGR10_1X10;
> +	__format->field = V4L2_FIELD_NONE;
> +	__format->colorspace = V4L2_COLORSPACE_SRGB;
> +	__format->ycbcr_enc = V4L2_MAP_YCBCR_ENC_DEFAULT(__format->colorspace);
> +	__format->quantization = V4L2_MAP_QUANTIZATION_DEFAULT(true,
> +				__format->colorspace, __format->ycbcr_enc);
> +	__format->xfer_func = V4L2_MAP_XFER_FUNC_DEFAULT(__format->colorspace);

Oh nice, I didn't know about the V4L2_MAP macros ;)

> +
> +	format->format = *__format;
> +
> +	return 0;
> +}
> +
> +static int ov7251_entity_init_cfg(struct v4l2_subdev *subdev,
> +				  struct v4l2_subdev_pad_config *cfg)
> +{
> +	struct v4l2_subdev_format fmt = { 0 };
> +
> +	fmt.which = cfg ? V4L2_SUBDEV_FORMAT_TRY : V4L2_SUBDEV_FORMAT_ACTIVE;
> +	fmt.format.width = 640;
> +	fmt.format.height = 480;
> +
> +	ov7251_set_format(subdev, cfg, &fmt);
> +
> +	return 0;
> +}
> +
> +static int ov7251_get_selection(struct v4l2_subdev *sd,
> +			   struct v4l2_subdev_pad_config *cfg,
> +			   struct v4l2_subdev_selection *sel)
> +{
> +	struct ov7251 *ov7251 = to_ov7251(sd);
> +
> +	if (sel->target != V4L2_SEL_TGT_CROP)
> +		return -EINVAL;
> +
> +	sel->r = *__ov7251_get_pad_crop(ov7251, cfg, sel->pad,
> +					sel->which);
> +	return 0;
> +}
> +
> +static int ov7251_s_stream(struct v4l2_subdev *subdev, int enable)
> +{
> +	struct ov7251 *ov7251 = to_ov7251(subdev);
> +	int ret;
> +
> +	if (enable) {
> +		ret = ov7251_set_register_array(ov7251,
> +					ov7251->current_mode->data,
> +					ov7251->current_mode->data_size);
> +		if (ret < 0) {
> +			dev_err(ov7251->dev, "could not set mode %dx%d\n",
> +				ov7251->current_mode->width,
> +				ov7251->current_mode->height);
> +			return ret;
> +		}
> +		ret = v4l2_ctrl_handler_setup(&ov7251->ctrls);
> +		if (ret < 0) {
> +			dev_err(ov7251->dev, "could not sync v4l2 controls\n");
> +			return ret;
> +		}
> +		ret = ov7251_write_reg(ov7251, OV7251_SC_MODE_SELECT,
> +				       OV7251_SC_MODE_SELECT_STREAMING);
> +		if (ret < 0)
> +			return ret;
> +	} else {
> +		ret = ov7251_write_reg(ov7251, OV7251_SC_MODE_SELECT,
> +				       OV7251_SC_MODE_SELECT_SW_STANDBY);
> +		if (ret < 0)
> +			return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static int ov7251_get_frame_interval(struct v4l2_subdev *subdev,
> +				     struct v4l2_subdev_frame_interval *fi)
> +{
> +	struct ov7251 *ov7251 = to_ov7251(subdev);
> +
> +	fi->interval = ov7251->current_mode->timeperframe;
> +
> +	return 0;
> +}
> +
> +static int ov7251_set_frame_interval(struct v4l2_subdev *subdev,
> +				     struct v4l2_subdev_frame_interval *fi)
> +{
> +	struct ov7251 *ov7251 = to_ov7251(subdev);
> +	const struct ov7251_mode_info *new_mode;
> +
> +	new_mode = ov7251_find_mode_by_ival(ov7251, &fi->interval);
> +
> +	if (new_mode != ov7251->current_mode) {
> +		int ret;
> +
> +		ret = v4l2_ctrl_s_ctrl_int64(ov7251->pixel_clock,
> +					     new_mode->pixel_clock);
> +		if (ret < 0)
> +			return ret;
> +
> +		ret = v4l2_ctrl_s_ctrl(ov7251->link_freq,
> +				       new_mode->link_freq);
> +		if (ret < 0)
> +			return ret;
> +
> +		ret = v4l2_ctrl_modify_range(ov7251->exposure,
> +					     1, new_mode->exposure_max,
> +					     1, new_mode->exposure_def);
> +		if (ret < 0)
> +			return ret;
> +
> +		ret = v4l2_ctrl_s_ctrl(ov7251->exposure,
> +				       new_mode->exposure_def);
> +		if (ret < 0)
> +			return ret;
> +
> +		ret = v4l2_ctrl_s_ctrl(ov7251->gain, 16);
> +		if (ret < 0)
> +			return ret;
> +
> +		ov7251->current_mode = new_mode;
> +	}
> +
> +	fi->interval = ov7251->current_mode->timeperframe;
> +
> +	return 0;
> +}
> +
> +static const struct v4l2_subdev_core_ops ov7251_core_ops = {
> +	.s_power = ov7251_s_power,
> +};
> +
> +static const struct v4l2_subdev_video_ops ov7251_video_ops = {
> +	.s_stream = ov7251_s_stream,
> +	.g_frame_interval = ov7251_get_frame_interval,
> +	.s_frame_interval = ov7251_set_frame_interval,
> +};
> +
> +static const struct v4l2_subdev_pad_ops ov7251_subdev_pad_ops = {
> +	.init_cfg = ov7251_entity_init_cfg,
> +	.enum_mbus_code = ov7251_enum_mbus_code,
> +	.enum_frame_size = ov7251_enum_frame_size,
> +	.enum_frame_interval = ov7251_enum_frame_ival,
> +	.get_fmt = ov7251_get_format,
> +	.set_fmt = ov7251_set_format,
> +	.get_selection = ov7251_get_selection,
> +};
> +
> +static const struct v4l2_subdev_ops ov7251_subdev_ops = {
> +	.core = &ov7251_core_ops,
> +	.video = &ov7251_video_ops,
> +	.pad = &ov7251_subdev_pad_ops,
> +};
> +
> +static int ov7251_probe(struct i2c_client *client,
> +			const struct i2c_device_id *id)
> +{
> +	struct device *dev = &client->dev;
> +	struct fwnode_handle *endpoint;
> +	struct ov7251 *ov7251;
> +	u8 chip_id_high, chip_id_low, chip_rev;
> +	u32 xclk_freq;
> +	int ret;
> +
> +	ov7251 = devm_kzalloc(dev, sizeof(struct ov7251), GFP_KERNEL);
> +	if (!ov7251)
> +		return -ENOMEM;
> +
> +	ov7251->i2c_client = client;
> +	ov7251->dev = dev;
> +
> +	endpoint = fwnode_graph_get_next_endpoint(dev_fwnode(dev), NULL);
> +	if (!endpoint) {
> +		dev_err(dev, "endpoint node not found\n");
> +		return -EINVAL;
> +	}
> +
> +	ret = v4l2_fwnode_endpoint_parse(endpoint, &ov7251->ep);
> +	fwnode_handle_put(endpoint);
> +	if (ret < 0) {
> +		dev_err(dev, "parsing endpoint node failed\n");
> +		return ret;
> +	}
> +
> +	if (ov7251->ep.bus_type != V4L2_MBUS_CSI2) {
> +		dev_err(dev, "invalid bus type (%u), must be CSI2 (%u)\n",
> +			ov7251->ep.bus_type, V4L2_MBUS_CSI2);
> +		return -EINVAL;
> +	}
> +
> +	/* get system clock (xclk) */
> +	ov7251->xclk = devm_clk_get(dev, "xclk");
> +	if (IS_ERR(ov7251->xclk)) {
> +		dev_err(dev, "could not get xclk");
> +		return PTR_ERR(ov7251->xclk);
> +	}
> +
> +	ret = of_property_read_u32(dev->of_node, "clock-frequency", &xclk_freq);
> +	if (ret) {
> +		dev_err(dev, "could not get xclk frequency\n");
> +		return ret;
> +	}
> +
> +	/* external clock must be 24MHz, allow 1% tolerance */
> +	if (xclk_freq < 23760000 || xclk_freq > 24240000) {
> +		dev_err(dev, "external clock frequency %u is not supported\n",
> +			xclk_freq);
> +		return -EINVAL;
> +	}
> +
> +	ret = clk_set_rate(ov7251->xclk, xclk_freq);
> +	if (ret) {
> +		dev_err(dev, "could not set xclk frequency\n");
> +		return ret;
> +	}
> +
> +	ov7251->io_regulator = devm_regulator_get(dev, "vdddo");
> +	if (IS_ERR(ov7251->io_regulator)) {
> +		dev_err(dev, "cannot get io regulator\n");
> +		return PTR_ERR(ov7251->io_regulator);
> +	}
> +
> +	ret = regulator_set_voltage(ov7251->io_regulator,
> +				    OV7251_VOLTAGE_DIGITAL_IO,
> +				    OV7251_VOLTAGE_DIGITAL_IO);
> +	if (ret < 0) {
> +		dev_err(dev, "cannot set io voltage\n");
> +		return ret;
> +	}
> +
> +	ov7251->core_regulator = devm_regulator_get(dev, "vddd");
> +	if (IS_ERR(ov7251->core_regulator)) {
> +		dev_err(dev, "cannot get core regulator\n");
> +		return PTR_ERR(ov7251->core_regulator);
> +	}
> +
> +	ret = regulator_set_voltage(ov7251->core_regulator,
> +				    OV7251_VOLTAGE_DIGITAL_CORE,
> +				    OV7251_VOLTAGE_DIGITAL_CORE);
> +	if (ret < 0) {
> +		dev_err(dev, "cannot set core voltage\n");
> +		return ret;
> +	}
> +
> +	ov7251->analog_regulator = devm_regulator_get(dev, "vdda");
> +	if (IS_ERR(ov7251->analog_regulator)) {
> +		dev_err(dev, "cannot get analog regulator\n");
> +		return PTR_ERR(ov7251->analog_regulator);
> +	}
> +
> +	ret = regulator_set_voltage(ov7251->analog_regulator,
> +				    OV7251_VOLTAGE_ANALOG,
> +				    OV7251_VOLTAGE_ANALOG);
> +	if (ret < 0) {
> +		dev_err(dev, "cannot set analog voltage\n");
> +		return ret;
> +	}
> +
> +	ov7251->enable_gpio = devm_gpiod_get(dev, "enable", GPIOD_OUT_HIGH);
> +	if (IS_ERR(ov7251->enable_gpio)) {
> +		dev_err(dev, "cannot get enable gpio\n");
> +		return PTR_ERR(ov7251->enable_gpio);
> +	}
> +
> +	mutex_init(&ov7251->power_lock);
> +
> +	v4l2_ctrl_handler_init(&ov7251->ctrls, 7);
> +	v4l2_ctrl_new_std(&ov7251->ctrls, &ov7251_ctrl_ops,
> +			  V4L2_CID_HFLIP, 0, 1, 1, 0);
> +	v4l2_ctrl_new_std(&ov7251->ctrls, &ov7251_ctrl_ops,
> +			  V4L2_CID_VFLIP, 0, 1, 1, 0);
> +	ov7251->exposure = v4l2_ctrl_new_std(&ov7251->ctrls, &ov7251_ctrl_ops,
> +					     V4L2_CID_EXPOSURE, 1, 32, 1, 32);
> +	ov7251->gain = v4l2_ctrl_new_std(&ov7251->ctrls, &ov7251_ctrl_ops,
> +					 V4L2_CID_GAIN, 16, 1023, 1, 16);
> +	v4l2_ctrl_new_std_menu_items(&ov7251->ctrls, &ov7251_ctrl_ops,
> +				     V4L2_CID_TEST_PATTERN,
> +				     ARRAY_SIZE(ov7251_test_pattern_menu) - 1,
> +				     0, 0, ov7251_test_pattern_menu);
> +	ov7251->pixel_clock = v4l2_ctrl_new_std(&ov7251->ctrls,
> +						&ov7251_ctrl_ops,
> +						V4L2_CID_PIXEL_RATE,
> +						1, INT_MAX, 1, 1);
> +	ov7251->link_freq = v4l2_ctrl_new_int_menu(&ov7251->ctrls,
> +						   &ov7251_ctrl_ops,
> +						   V4L2_CID_LINK_FREQ,
> +						   ARRAY_SIZE(link_freq) - 1,
> +						   0, link_freq);
> +	if (ov7251->link_freq)
> +		ov7251->link_freq->flags |= V4L2_CTRL_FLAG_READ_ONLY;
> +
> +	ov7251->sd.ctrl_handler = &ov7251->ctrls;
> +
> +	if (ov7251->ctrls.error) {
> +		dev_err(dev, "%s: control initialization error %d\n",
> +		       __func__, ov7251->ctrls.error);
> +		ret = ov7251->ctrls.error;
> +		goto free_ctrl;
> +	}
> +
> +	v4l2_i2c_subdev_init(&ov7251->sd, client, &ov7251_subdev_ops);
> +	ov7251->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
> +	ov7251->pad.flags = MEDIA_PAD_FL_SOURCE;
> +	ov7251->sd.dev = &client->dev;
> +	ov7251->sd.entity.function = MEDIA_ENT_F_CAM_SENSOR;
> +
> +	ret = media_entity_pads_init(&ov7251->sd.entity, 1, &ov7251->pad);
> +	if (ret < 0) {
> +		dev_err(dev, "could not register media entity\n");
> +		goto free_ctrl;
> +	}
> +
> +	ret = ov7251_s_power(&ov7251->sd, true);
> +	if (ret < 0) {
> +		dev_err(dev, "could not power up OV7251\n");
> +		goto free_entity;
> +	}
> +
> +	ret = ov7251_read_reg(ov7251, OV7251_CHIP_ID_HIGH, &chip_id_high);
> +	if (ret < 0 || chip_id_high != OV7251_CHIP_ID_HIGH_BYTE) {
> +		dev_err(dev, "could not read ID high\n");
> +		ret = -ENODEV;
> +		goto power_down;
> +	}
> +	ret = ov7251_read_reg(ov7251, OV7251_CHIP_ID_LOW, &chip_id_low);
> +	if (ret < 0 || chip_id_low != OV7251_CHIP_ID_LOW_BYTE) {
> +		dev_err(dev, "could not read ID low\n");
> +		ret = -ENODEV;
> +		goto power_down;
> +	}
> +
> +	ret = ov7251_read_reg(ov7251, OV7251_SC_GP_IO_IN1, &chip_rev);
> +	if (ret < 0) {
> +		dev_err(dev, "could not read revision\n");
> +		ret = -ENODEV;
> +		goto power_down;
> +	}
> +	chip_rev >>= 4;
> +
> +	dev_info(dev, "OV7251 revision %x (%s) detected at address 0x%02x\n",
> +		 chip_rev,
> +		 chip_rev == 0x4 ? "1A / 1B" :
> +		 chip_rev == 0x5 ? "1C / 1D" :
> +		 chip_rev == 0x6 ? "1E" :
> +		 chip_rev == 0x7 ? "1F" : "unknown",
> +		 client->addr);
> +
> +	ret = ov7251_read_reg(ov7251, OV7251_PRE_ISP_00,
> +			      &ov7251->pre_isp_00);
> +	if (ret < 0) {
> +		dev_err(dev, "could not read test pattern value\n");
> +		ret = -ENODEV;
> +		goto power_down;
> +	}
> +
> +	ret = ov7251_read_reg(ov7251, OV7251_TIMING_FORMAT1,
> +			      &ov7251->timing_format1);
> +	if (ret < 0) {
> +		dev_err(dev, "could not read vflip value\n");
> +		ret = -ENODEV;
> +		goto power_down;
> +	}
> +
> +	ret = ov7251_read_reg(ov7251, OV7251_TIMING_FORMAT2,
> +			      &ov7251->timing_format2);
> +	if (ret < 0) {
> +		dev_err(dev, "could not read hflip value\n");
> +		ret = -ENODEV;
> +		goto power_down;
> +	}
> +
> +	ov7251_s_power(&ov7251->sd, false);
> +
> +	ret = v4l2_async_register_subdev(&ov7251->sd);
> +	if (ret < 0) {
> +		dev_err(dev, "could not register v4l2 device\n");
> +		goto free_entity;
> +	}
> +
> +	ov7251_entity_init_cfg(&ov7251->sd, NULL);
> +
> +	return 0;
> +
> +power_down:
> +	ov7251_s_power(&ov7251->sd, false);
> +free_entity:
> +	media_entity_cleanup(&ov7251->sd.entity);
> +free_ctrl:
> +	v4l2_ctrl_handler_free(&ov7251->ctrls);
> +	mutex_destroy(&ov7251->power_lock);
> +
> +	return ret;
> +}
> +
> +static int ov7251_remove(struct i2c_client *client)
> +{
> +	struct v4l2_subdev *sd = i2c_get_clientdata(client);
> +	struct ov7251 *ov7251 = to_ov7251(sd);
> +
> +	v4l2_async_unregister_subdev(&ov7251->sd);
> +	media_entity_cleanup(&ov7251->sd.entity);
> +	v4l2_ctrl_handler_free(&ov7251->ctrls);
> +	mutex_destroy(&ov7251->power_lock);
> +
> +	return 0;
> +}
> +
> +static const struct i2c_device_id ov7251_id[] = {
> +	{ "ov7251", 0 },
> +	{}
> +};
> +MODULE_DEVICE_TABLE(i2c, ov7251_id);
> +
> +static const struct of_device_id ov7251_of_match[] = {
> +	{ .compatible = "ovti,ov7251" },
> +	{ /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, ov7251_of_match);
> +
> +static struct i2c_driver ov7251_i2c_driver = {
> +	.driver = {
> +		.of_match_table = of_match_ptr(ov7251_of_match),
> +		.name  = "ov7251",
> +	},
> +	.probe  = ov7251_probe,
> +	.remove = ov7251_remove,
> +	.id_table = ov7251_id,

As this driver depends on CONFIG_OF, I've been suggested to use probe_new and
get rid of i2c id_tables.

With the above nits clarified, and as you addressed my v1 comments:

Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>

Thanks
   j

> +};
> +
> +module_i2c_driver(ov7251_i2c_driver);
> +
> +MODULE_DESCRIPTION("Omnivision OV7251 Camera Driver");
> +MODULE_AUTHOR("Todor Tomov <todor.tomov@linaro.org>");
> +MODULE_LICENSE("GPL v2");
Todor Tomov March 29, 2018, 7:50 a.m. UTC | #2
Hi Jacopo,

Thank you for your prompt review.

On 23.03.2018 15:40, jacopo mondi wrote:
> Hi Todor,
>    thanks for the patch.
> 
> When running checkpatch --strict I see a few warning you can easily
> close (braces indentation mostly, and one additional empty line at
> line 1048).

Thank you for pointing me to the --strict mode. There are a few CHECKs for
braces alignment for which the alignment is still better as it is now
I think. However there were also a few reasonable points and I have
updated the code according to them.

> 
> A few more nits below.
> 
> On Fri, Mar 23, 2018 at 12:14:20PM +0800, Todor Tomov wrote:
>> The ov7251 sensor is a 1/7.5-Inch B&W VGA (640x480) CMOS Digital Image
>> Sensor from Omnivision.
>>
>> The driver supports the following modes:
>> - 640x480 30fps
>> - 640x480 60fps
>> - 640x480 90fps
>>
>> Output format is MIPI RAW 10.
>>
>> The driver supports configuration via user controls for:
>> - exposure and gain;
>> - horizontal and vertical flip;
>> - test pattern.
>>
>> Signed-off-by: Todor Tomov <todor.tomov@linaro.org>
>> ---
>>  drivers/media/i2c/Kconfig  |   13 +
>>  drivers/media/i2c/Makefile |    1 +
>>  drivers/media/i2c/ov7251.c | 1494 ++++++++++++++++++++++++++++++++++++++++++++
>>  3 files changed, 1508 insertions(+)
>>  create mode 100644 drivers/media/i2c/ov7251.c
>>
>> diff --git a/drivers/media/i2c/Kconfig b/drivers/media/i2c/Kconfig
>> index 541f0d28..89aecb3 100644
>> --- a/drivers/media/i2c/Kconfig
>> +++ b/drivers/media/i2c/Kconfig
>> @@ -688,6 +688,19 @@ config VIDEO_OV5695
>>  	  To compile this driver as a module, choose M here: the
>>  	  module will be called ov5695.
>>
>> +config VIDEO_OV7251
>> +	tristate "OmniVision OV7251 sensor support"
>> +	depends on OF
>> +	depends on I2C && VIDEO_V4L2 && VIDEO_V4L2_SUBDEV_API
>> +	depends on MEDIA_CAMERA_SUPPORT
>> +	select V4L2_FWNODE
>> +	---help---
>> +	  This is a Video4Linux2 sensor-level driver for the OmniVision
>> +	  OV7251 camera.
>> +
>> +	  To compile this driver as a module, choose M here: the
>> +	  module will be called ov7251.
>> +
>>  config VIDEO_OV772X
>>  	tristate "OmniVision OV772x sensor support"
>>  	depends on I2C && VIDEO_V4L2
>> diff --git a/drivers/media/i2c/Makefile b/drivers/media/i2c/Makefile
>> index ea34aee..c8585b1 100644
>> --- a/drivers/media/i2c/Makefile
>> +++ b/drivers/media/i2c/Makefile
>> @@ -70,6 +70,7 @@ obj-$(CONFIG_VIDEO_OV5647) += ov5647.o
>>  obj-$(CONFIG_VIDEO_OV5670) += ov5670.o
>>  obj-$(CONFIG_VIDEO_OV5695) += ov5695.o
>>  obj-$(CONFIG_VIDEO_OV6650) += ov6650.o
>> +obj-$(CONFIG_VIDEO_OV7251) += ov7251.o
>>  obj-$(CONFIG_VIDEO_OV7640) += ov7640.o
>>  obj-$(CONFIG_VIDEO_OV7670) += ov7670.o
>>  obj-$(CONFIG_VIDEO_OV772X) += ov772x.o
>> diff --git a/drivers/media/i2c/ov7251.c b/drivers/media/i2c/ov7251.c
>> new file mode 100644
>> index 0000000..7b401a9
>> --- /dev/null
>> +++ b/drivers/media/i2c/ov7251.c
>> @@ -0,0 +1,1494 @@

<snip>

>> +static int ov7251_s_power(struct v4l2_subdev *sd, int on)
>> +{
>> +	struct ov7251 *ov7251 = to_ov7251(sd);
>> +	int ret = 0;
>> +
>> +	mutex_lock(&ov7251->power_lock);
>> +
>> +	/*
>> +	 * If the power state is modified from 0 to 1 or from 1 to 0,
>> +	 * update the power state.
>> +	 */
>> +	if (ov7251->power_on == !on) {
> 
>         if (ov7251->power_on == !!on) {
>                 mutex_unlock(&ov7251->power_lock);
>                 return 0;
>         }
> 
> And you can save one indentation level and remove ret initialization.
> 

Good hint, I'd rather save one indentation level by:

	if (ov7251->power_on == !!on)
		goto exit;

> 
>> +		if (on) {
>> +			ret = ov7251_set_power_on(ov7251);
>> +			if (ret < 0)
>> +				goto exit;
>> +
>> +			ret = ov7251_set_register_array(ov7251,
>> +					ov7251_global_init_setting,
>> +					ARRAY_SIZE(ov7251_global_init_setting));
>> +			if (ret < 0) {
>> +				dev_err(ov7251->dev,
>> +					"could not set init registers\n");
>> +				ov7251_set_power_off(ov7251);
>> +				goto exit;
>> +			}
>> +
>> +			ov7251->power_on = true;
>> +		} else {
>> +			ov7251_set_power_off(ov7251);
>> +			ov7251->power_on = false;
>> +		}
>> +	}
>> +
>> +exit:
>> +	mutex_unlock(&ov7251->power_lock);
>> +
>> +	return ret;
>> +}
>> +

<snip>

>> +
>> +static int ov7251_enum_frame_size(struct v4l2_subdev *subdev,
>> +				  struct v4l2_subdev_pad_config *cfg,
>> +				  struct v4l2_subdev_frame_size_enum *fse)
>> +{
> 
> Shouldn't you check for (pad != 0) in all subdev pad operations?
> I see other driver with a single pad doing this...

I looked up now and I can see that this is checked in v4l2-subdev.c
in subdev_do_ioctl() before the driver's callback is called.

> 
> 
>> +	if (fse->code != MEDIA_BUS_FMT_SBGGR10_1X10)
>> +		return -EINVAL;
>> +
>> +	if (fse->index >= ARRAY_SIZE(ov7251_mode_info_data))
>> +		return -EINVAL;
>> +
>> +	fse->min_width = ov7251_mode_info_data[fse->index].width;
>> +	fse->max_width = ov7251_mode_info_data[fse->index].width;
>> +	fse->min_height = ov7251_mode_info_data[fse->index].height;
>> +	fse->max_height = ov7251_mode_info_data[fse->index].height;
>> +
>> +	return 0;
>> +}
>> +

<snip>

>> +
>> +static const struct i2c_device_id ov7251_id[] = {
>> +	{ "ov7251", 0 },
>> +	{}
>> +};
>> +MODULE_DEVICE_TABLE(i2c, ov7251_id);
>> +
>> +static const struct of_device_id ov7251_of_match[] = {
>> +	{ .compatible = "ovti,ov7251" },
>> +	{ /* sentinel */ }
>> +};
>> +MODULE_DEVICE_TABLE(of, ov7251_of_match);
>> +
>> +static struct i2c_driver ov7251_i2c_driver = {
>> +	.driver = {
>> +		.of_match_table = of_match_ptr(ov7251_of_match),
>> +		.name  = "ov7251",
>> +	},
>> +	.probe  = ov7251_probe,
>> +	.remove = ov7251_remove,
>> +	.id_table = ov7251_id,
> 
> As this driver depends on CONFIG_OF, I've been suggested to use probe_new and
> get rid of i2c id_tables.

Yes, I'll do that.

> 
> With the above nits clarified, and as you addressed my v1 comments:
> 
> Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>

Would you like to see the corrections or I can add the tag before sending them?

> 
> Thanks
>    j
> 
>> +};
>> +
>> +module_i2c_driver(ov7251_i2c_driver);
>> +
>> +MODULE_DESCRIPTION("Omnivision OV7251 Camera Driver");
>> +MODULE_AUTHOR("Todor Tomov <todor.tomov@linaro.org>");
>> +MODULE_LICENSE("GPL v2");
Sakari Ailus March 29, 2018, 8:29 a.m. UTC | #3
Hi Todor and Jacopo,

On Thu, Mar 29, 2018 at 10:50:10AM +0300, Todor Tomov wrote:
...
> >> +static const struct of_device_id ov7251_of_match[] = {
> >> +	{ .compatible = "ovti,ov7251" },
> >> +	{ /* sentinel */ }
> >> +};
> >> +MODULE_DEVICE_TABLE(of, ov7251_of_match);
> >> +
> >> +static struct i2c_driver ov7251_i2c_driver = {
> >> +	.driver = {
> >> +		.of_match_table = of_match_ptr(ov7251_of_match),
> >> +		.name  = "ov7251",
> >> +	},
> >> +	.probe  = ov7251_probe,
> >> +	.remove = ov7251_remove,
> >> +	.id_table = ov7251_id,
> > 
> > As this driver depends on CONFIG_OF, I've been suggested to use probe_new and
> > get rid of i2c id_tables.
> 
> Yes, I'll do that.

The proposal sounds good to me but rather than adding CONFIG_OF dependency,
I'd instead suggest changing the of_property_read_u32 to
fwnode_property_read_u32; then the driver may work on ACPI based systems as
well. There's another change needed, too, which is not using of_match_ptr
macro, but instead assigning the of_match_table unconditionally.

Up to you.
Todor Tomov March 29, 2018, 10:09 a.m. UTC | #4
Hi Sakari

On 29.03.2018 11:29, Sakari Ailus wrote:
> Hi Todor and Jacopo,
> 
> On Thu, Mar 29, 2018 at 10:50:10AM +0300, Todor Tomov wrote:
> ...
>>>> +static const struct of_device_id ov7251_of_match[] = {
>>>> +	{ .compatible = "ovti,ov7251" },
>>>> +	{ /* sentinel */ }
>>>> +};
>>>> +MODULE_DEVICE_TABLE(of, ov7251_of_match);
>>>> +
>>>> +static struct i2c_driver ov7251_i2c_driver = {
>>>> +	.driver = {
>>>> +		.of_match_table = of_match_ptr(ov7251_of_match),
>>>> +		.name  = "ov7251",
>>>> +	},
>>>> +	.probe  = ov7251_probe,
>>>> +	.remove = ov7251_remove,
>>>> +	.id_table = ov7251_id,
>>>
>>> As this driver depends on CONFIG_OF, I've been suggested to use probe_new and
>>> get rid of i2c id_tables.
>>
>> Yes, I'll do that.
> 
> The proposal sounds good to me but rather than adding CONFIG_OF dependency,
> I'd instead suggest changing the of_property_read_u32 to
> fwnode_property_read_u32; then the driver may work on ACPI based systems as
> well. 

Ok.

> There's another change needed, too, which is not using of_match_ptr
> macro, but instead assigning the of_match_table unconditionally.

In that case the MODULE_DEVICE_TABLE(i2c, ...) is again not needed?
And matching will be again via of_match_table?

> 
> Up to you.
> 

Thank you for your help!
 
Best regards,
Todor Tomov
Sakari Ailus March 29, 2018, 10:21 a.m. UTC | #5
Hi Todor,

On Thu, Mar 29, 2018 at 01:09:18PM +0300, Todor Tomov wrote:
> > There's another change needed, too, which is not using of_match_ptr
> > macro, but instead assigning the of_match_table unconditionally.
> 
> In that case the MODULE_DEVICE_TABLE(i2c, ...) is again not needed?
> And matching will be again via of_match_table?

Correct.
Jacopo Mondi March 29, 2018, 11:11 a.m. UTC | #6
Hi Todor,

On Thu, Mar 29, 2018 at 10:50:10AM +0300, Todor Tomov wrote:
> Hi Jacopo,
>
>
> >
> > With the above nits clarified, and as you addressed my v1 comments:
> >
> > Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
>
> Would you like to see the corrections or I can add the tag before sending them?
>

I don't have any more comment, feel free to add it :)

Thanks
   j
Sakari Ailus March 29, 2018, 11:51 a.m. UTC | #7
Hi Todor,

Thanks for the patch. A few quick comments below...

On Fri, Mar 23, 2018 at 12:14:20PM +0800, Todor Tomov wrote:
> The ov7251 sensor is a 1/7.5-Inch B&W VGA (640x480) CMOS Digital Image
> Sensor from Omnivision.
> 
> The driver supports the following modes:
> - 640x480 30fps
> - 640x480 60fps
> - 640x480 90fps
> 
> Output format is MIPI RAW 10.
> 
> The driver supports configuration via user controls for:
> - exposure and gain;
> - horizontal and vertical flip;
> - test pattern.
> 
> Signed-off-by: Todor Tomov <todor.tomov@linaro.org>
> ---
>  drivers/media/i2c/Kconfig  |   13 +
>  drivers/media/i2c/Makefile |    1 +
>  drivers/media/i2c/ov7251.c | 1494 ++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 1508 insertions(+)
>  create mode 100644 drivers/media/i2c/ov7251.c
> 
> diff --git a/drivers/media/i2c/Kconfig b/drivers/media/i2c/Kconfig
> index 541f0d28..89aecb3 100644
> --- a/drivers/media/i2c/Kconfig
> +++ b/drivers/media/i2c/Kconfig
> @@ -688,6 +688,19 @@ config VIDEO_OV5695
>  	  To compile this driver as a module, choose M here: the
>  	  module will be called ov5695.
>  
> +config VIDEO_OV7251
> +	tristate "OmniVision OV7251 sensor support"
> +	depends on OF
> +	depends on I2C && VIDEO_V4L2 && VIDEO_V4L2_SUBDEV_API
> +	depends on MEDIA_CAMERA_SUPPORT
> +	select V4L2_FWNODE
> +	---help---
> +	  This is a Video4Linux2 sensor-level driver for the OmniVision
> +	  OV7251 camera.
> +
> +	  To compile this driver as a module, choose M here: the
> +	  module will be called ov7251.
> +
>  config VIDEO_OV772X
>  	tristate "OmniVision OV772x sensor support"
>  	depends on I2C && VIDEO_V4L2
> diff --git a/drivers/media/i2c/Makefile b/drivers/media/i2c/Makefile
> index ea34aee..c8585b1 100644
> --- a/drivers/media/i2c/Makefile
> +++ b/drivers/media/i2c/Makefile
> @@ -70,6 +70,7 @@ obj-$(CONFIG_VIDEO_OV5647) += ov5647.o
>  obj-$(CONFIG_VIDEO_OV5670) += ov5670.o
>  obj-$(CONFIG_VIDEO_OV5695) += ov5695.o
>  obj-$(CONFIG_VIDEO_OV6650) += ov6650.o
> +obj-$(CONFIG_VIDEO_OV7251) += ov7251.o
>  obj-$(CONFIG_VIDEO_OV7640) += ov7640.o
>  obj-$(CONFIG_VIDEO_OV7670) += ov7670.o
>  obj-$(CONFIG_VIDEO_OV772X) += ov772x.o
> diff --git a/drivers/media/i2c/ov7251.c b/drivers/media/i2c/ov7251.c
> new file mode 100644
> index 0000000..7b401a9
> --- /dev/null
> +++ b/drivers/media/i2c/ov7251.c
> @@ -0,0 +1,1494 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Driver for the OV7251 camera sensor.
> + *
> + * Copyright (c) 2017-2018, The Linux Foundation. All rights reserved.
> + * Copyright (c) 2017-2018, Linaro Ltd.
> + */
> +
> +#include <linux/bitops.h>
> +#include <linux/clk.h>
> +#include <linux/delay.h>
> +#include <linux/device.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/i2c.h>
> +#include <linux/init.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_graph.h>
> +#include <linux/regulator/consumer.h>
> +#include <linux/slab.h>
> +#include <linux/types.h>
> +#include <media/v4l2-ctrls.h>
> +#include <media/v4l2-fwnode.h>
> +#include <media/v4l2-subdev.h>
> +
> +#define OV7251_VOLTAGE_ANALOG               2800000
> +#define OV7251_VOLTAGE_DIGITAL_CORE         1500000
> +#define OV7251_VOLTAGE_DIGITAL_IO           1800000
> +
> +#define OV7251_SC_MODE_SELECT		0x0100
> +#define OV7251_SC_MODE_SELECT_SW_STANDBY	0x0
> +#define OV7251_SC_MODE_SELECT_STREAMING		0x1
> +
> +#define OV7251_CHIP_ID_HIGH		0x300a
> +#define OV7251_CHIP_ID_HIGH_BYTE	0x77
> +#define OV7251_CHIP_ID_LOW		0x300b
> +#define OV7251_CHIP_ID_LOW_BYTE		0x50
> +#define OV7251_SC_GP_IO_IN1		0x3029
> +#define OV7251_AEC_EXPO_0		0x3500
> +#define OV7251_AEC_EXPO_1		0x3501
> +#define OV7251_AEC_EXPO_2		0x3502
> +#define OV7251_AEC_AGC_ADJ_0		0x350a
> +#define OV7251_AEC_AGC_ADJ_1		0x350b
> +#define OV7251_TIMING_FORMAT1		0x3820
> +#define OV7251_TIMING_FORMAT1_VFLIP	BIT(2)
> +#define OV7251_TIMING_FORMAT2		0x3821
> +#define OV7251_TIMING_FORMAT2_MIRROR	BIT(2)
> +#define OV7251_PRE_ISP_00		0x5e00
> +#define OV7251_PRE_ISP_00_TEST_PATTERN	BIT(7)
> +
> +struct reg_value {
> +	u16 reg;
> +	u8 val;
> +};
> +
> +struct ov7251_mode_info {
> +	u32 width;
> +	u32 height;
> +	const struct reg_value *data;
> +	u32 data_size;
> +	u32 pixel_clock;
> +	u32 link_freq;
> +	u16 exposure_max;
> +	u16 exposure_def;
> +	struct v4l2_fract timeperframe;
> +};
> +
> +struct ov7251 {
> +	struct i2c_client *i2c_client;
> +	struct device *dev;
> +	struct v4l2_subdev sd;
> +	struct media_pad pad;
> +	struct v4l2_fwnode_endpoint ep;
> +	struct v4l2_mbus_framefmt fmt;
> +	struct v4l2_rect crop;
> +	struct clk *xclk;
> +
> +	struct regulator *io_regulator;
> +	struct regulator *core_regulator;
> +	struct regulator *analog_regulator;
> +
> +	const struct ov7251_mode_info *current_mode;
> +
> +	struct v4l2_ctrl_handler ctrls;
> +	struct v4l2_ctrl *pixel_clock;
> +	struct v4l2_ctrl *link_freq;
> +	struct v4l2_ctrl *exposure;
> +	struct v4l2_ctrl *gain;
> +
> +	/* Cached register values */
> +	u8 aec_pk_manual;
> +	u8 pre_isp_00;
> +	u8 timing_format1;
> +	u8 timing_format2;
> +
> +	struct mutex power_lock; /* lock to protect power state */
> +	bool power_on;
> +
> +	struct gpio_desc *enable_gpio;
> +};
> +
> +static inline struct ov7251 *to_ov7251(struct v4l2_subdev *sd)
> +{
> +	return container_of(sd, struct ov7251, sd);
> +}
> +
> +static const struct reg_value ov7251_global_init_setting[] = {
> +	{ 0x0103, 0x01 },
> +	{ 0x303b, 0x02 },
> +};
> +
> +static const struct reg_value ov7251_setting_vga_30fps[] = {
> +	{ 0x3005, 0x00 },
> +	{ 0x3012, 0xc0 },
> +	{ 0x3013, 0xd2 },
> +	{ 0x3014, 0x04 },
> +	{ 0x3016, 0xf0 },
> +	{ 0x3017, 0xf0 },
> +	{ 0x3018, 0xf0 },
> +	{ 0x301a, 0xf0 },
> +	{ 0x301b, 0xf0 },
> +	{ 0x301c, 0xf0 },
> +	{ 0x3023, 0x05 },
> +	{ 0x3037, 0xf0 },
> +	{ 0x3098, 0x04 }, /* pll2 pre divider */
> +	{ 0x3099, 0x28 }, /* pll2 multiplier */
> +	{ 0x309a, 0x05 }, /* pll2 sys divider */
> +	{ 0x309b, 0x04 }, /* pll2 adc divider */
> +	{ 0x309d, 0x00 }, /* pll2 divider */
> +	{ 0x30b0, 0x0a }, /* pll1 pix divider */
> +	{ 0x30b1, 0x01 }, /* pll1 divider */
> +	{ 0x30b3, 0x64 }, /* pll1 multiplier */
> +	{ 0x30b4, 0x03 }, /* pll1 pre divider */
> +	{ 0x30b5, 0x05 }, /* pll1 mipi divider */
> +	{ 0x3106, 0xda },
> +	{ 0x3503, 0x07 },
> +	{ 0x3509, 0x10 },
> +	{ 0x3600, 0x1c },
> +	{ 0x3602, 0x62 },
> +	{ 0x3620, 0xb7 },
> +	{ 0x3622, 0x04 },
> +	{ 0x3626, 0x21 },
> +	{ 0x3627, 0x30 },
> +	{ 0x3630, 0x44 },
> +	{ 0x3631, 0x35 },
> +	{ 0x3634, 0x60 },
> +	{ 0x3636, 0x00 },
> +	{ 0x3662, 0x01 },
> +	{ 0x3663, 0x70 },
> +	{ 0x3664, 0x50 },
> +	{ 0x3666, 0x0a },
> +	{ 0x3669, 0x1a },
> +	{ 0x366a, 0x00 },
> +	{ 0x366b, 0x50 },
> +	{ 0x3673, 0x01 },
> +	{ 0x3674, 0xff },
> +	{ 0x3675, 0x03 },
> +	{ 0x3705, 0xc1 },
> +	{ 0x3709, 0x40 },
> +	{ 0x373c, 0x08 },
> +	{ 0x3742, 0x00 },
> +	{ 0x3757, 0xb3 },
> +	{ 0x3788, 0x00 },
> +	{ 0x37a8, 0x01 },
> +	{ 0x37a9, 0xc0 },
> +	{ 0x3800, 0x00 },
> +	{ 0x3801, 0x04 },
> +	{ 0x3802, 0x00 },
> +	{ 0x3803, 0x04 },
> +	{ 0x3804, 0x02 },
> +	{ 0x3805, 0x8b },
> +	{ 0x3806, 0x01 },
> +	{ 0x3807, 0xeb },
> +	{ 0x3808, 0x02 }, /* width high */
> +	{ 0x3809, 0x80 }, /* width low */
> +	{ 0x380a, 0x01 }, /* height high */
> +	{ 0x380b, 0xe0 }, /* height low */
> +	{ 0x380c, 0x03 }, /* total horiz timing high */
> +	{ 0x380d, 0xa0 }, /* total horiz timing low */
> +	{ 0x380e, 0x06 }, /* total vertical timing high */
> +	{ 0x380f, 0xbc }, /* total vertical timing low */
> +	{ 0x3810, 0x00 },
> +	{ 0x3811, 0x04 },
> +	{ 0x3812, 0x00 },
> +	{ 0x3813, 0x05 },
> +	{ 0x3814, 0x11 },
> +	{ 0x3815, 0x11 },
> +	{ 0x3820, 0x40 },
> +	{ 0x3821, 0x00 },
> +	{ 0x382f, 0x0e },
> +	{ 0x3832, 0x00 },
> +	{ 0x3833, 0x05 },
> +	{ 0x3834, 0x00 },
> +	{ 0x3835, 0x0c },
> +	{ 0x3837, 0x00 },
> +	{ 0x3b80, 0x00 },
> +	{ 0x3b81, 0xa5 },
> +	{ 0x3b82, 0x10 },
> +	{ 0x3b83, 0x00 },
> +	{ 0x3b84, 0x08 },
> +	{ 0x3b85, 0x00 },
> +	{ 0x3b86, 0x01 },
> +	{ 0x3b87, 0x00 },
> +	{ 0x3b88, 0x00 },
> +	{ 0x3b89, 0x00 },
> +	{ 0x3b8a, 0x00 },
> +	{ 0x3b8b, 0x05 },
> +	{ 0x3b8c, 0x00 },
> +	{ 0x3b8d, 0x00 },
> +	{ 0x3b8e, 0x00 },
> +	{ 0x3b8f, 0x1a },
> +	{ 0x3b94, 0x05 },
> +	{ 0x3b95, 0xf2 },
> +	{ 0x3b96, 0x40 },
> +	{ 0x3c00, 0x89 },
> +	{ 0x3c01, 0x63 },
> +	{ 0x3c02, 0x01 },
> +	{ 0x3c03, 0x00 },
> +	{ 0x3c04, 0x00 },
> +	{ 0x3c05, 0x03 },
> +	{ 0x3c06, 0x00 },
> +	{ 0x3c07, 0x06 },
> +	{ 0x3c0c, 0x01 },
> +	{ 0x3c0d, 0xd0 },
> +	{ 0x3c0e, 0x02 },
> +	{ 0x3c0f, 0x0a },
> +	{ 0x4001, 0x42 },
> +	{ 0x4004, 0x04 },
> +	{ 0x4005, 0x00 },
> +	{ 0x404e, 0x01 },
> +	{ 0x4300, 0xff },
> +	{ 0x4301, 0x00 },
> +	{ 0x4315, 0x00 },
> +	{ 0x4501, 0x48 },
> +	{ 0x4600, 0x00 },
> +	{ 0x4601, 0x4e },
> +	{ 0x4801, 0x0f },
> +	{ 0x4806, 0x0f },
> +	{ 0x4819, 0xaa },
> +	{ 0x4823, 0x3e },
> +	{ 0x4837, 0x19 },
> +	{ 0x4a0d, 0x00 },
> +	{ 0x4a47, 0x7f },
> +	{ 0x4a49, 0xf0 },
> +	{ 0x4a4b, 0x30 },
> +	{ 0x5000, 0x85 },
> +	{ 0x5001, 0x80 },
> +};
> +
> +static const struct reg_value ov7251_setting_vga_60fps[] = {
> +	{ 0x3005, 0x00 },
> +	{ 0x3012, 0xc0 },
> +	{ 0x3013, 0xd2 },
> +	{ 0x3014, 0x04 },
> +	{ 0x3016, 0x10 },
> +	{ 0x3017, 0x00 },
> +	{ 0x3018, 0x00 },
> +	{ 0x301a, 0x00 },
> +	{ 0x301b, 0x00 },
> +	{ 0x301c, 0x00 },
> +	{ 0x3023, 0x05 },
> +	{ 0x3037, 0xf0 },
> +	{ 0x3098, 0x04 }, /* pll2 pre divider */
> +	{ 0x3099, 0x28 }, /* pll2 multiplier */
> +	{ 0x309a, 0x05 }, /* pll2 sys divider */
> +	{ 0x309b, 0x04 }, /* pll2 adc divider */
> +	{ 0x309d, 0x00 }, /* pll2 divider */
> +	{ 0x30b0, 0x0a }, /* pll1 pix divider */
> +	{ 0x30b1, 0x01 }, /* pll1 divider */
> +	{ 0x30b3, 0x64 }, /* pll1 multiplier */
> +	{ 0x30b4, 0x03 }, /* pll1 pre divider */
> +	{ 0x30b5, 0x05 }, /* pll1 mipi divider */
> +	{ 0x3106, 0xda },
> +	{ 0x3503, 0x07 },
> +	{ 0x3509, 0x10 },
> +	{ 0x3600, 0x1c },
> +	{ 0x3602, 0x62 },
> +	{ 0x3620, 0xb7 },
> +	{ 0x3622, 0x04 },
> +	{ 0x3626, 0x21 },
> +	{ 0x3627, 0x30 },
> +	{ 0x3630, 0x44 },
> +	{ 0x3631, 0x35 },
> +	{ 0x3634, 0x60 },
> +	{ 0x3636, 0x00 },
> +	{ 0x3662, 0x01 },
> +	{ 0x3663, 0x70 },
> +	{ 0x3664, 0x50 },
> +	{ 0x3666, 0x0a },
> +	{ 0x3669, 0x1a },
> +	{ 0x366a, 0x00 },
> +	{ 0x366b, 0x50 },
> +	{ 0x3673, 0x01 },
> +	{ 0x3674, 0xff },
> +	{ 0x3675, 0x03 },
> +	{ 0x3705, 0xc1 },
> +	{ 0x3709, 0x40 },
> +	{ 0x373c, 0x08 },
> +	{ 0x3742, 0x00 },
> +	{ 0x3757, 0xb3 },
> +	{ 0x3788, 0x00 },
> +	{ 0x37a8, 0x01 },
> +	{ 0x37a9, 0xc0 },
> +	{ 0x3800, 0x00 },
> +	{ 0x3801, 0x04 },
> +	{ 0x3802, 0x00 },
> +	{ 0x3803, 0x04 },
> +	{ 0x3804, 0x02 },
> +	{ 0x3805, 0x8b },
> +	{ 0x3806, 0x01 },
> +	{ 0x3807, 0xeb },
> +	{ 0x3808, 0x02 }, /* width high */
> +	{ 0x3809, 0x80 }, /* width low */
> +	{ 0x380a, 0x01 }, /* height high */
> +	{ 0x380b, 0xe0 }, /* height low */
> +	{ 0x380c, 0x03 }, /* total horiz timing high */
> +	{ 0x380d, 0xa0 }, /* total horiz timing low */
> +	{ 0x380e, 0x03 }, /* total vertical timing high */
> +	{ 0x380f, 0x5c }, /* total vertical timing low */
> +	{ 0x3810, 0x00 },
> +	{ 0x3811, 0x04 },
> +	{ 0x3812, 0x00 },
> +	{ 0x3813, 0x05 },
> +	{ 0x3814, 0x11 },
> +	{ 0x3815, 0x11 },
> +	{ 0x3820, 0x40 },
> +	{ 0x3821, 0x00 },
> +	{ 0x382f, 0x0e },
> +	{ 0x3832, 0x00 },
> +	{ 0x3833, 0x05 },
> +	{ 0x3834, 0x00 },
> +	{ 0x3835, 0x0c },
> +	{ 0x3837, 0x00 },
> +	{ 0x3b80, 0x00 },
> +	{ 0x3b81, 0xa5 },
> +	{ 0x3b82, 0x10 },
> +	{ 0x3b83, 0x00 },
> +	{ 0x3b84, 0x08 },
> +	{ 0x3b85, 0x00 },
> +	{ 0x3b86, 0x01 },
> +	{ 0x3b87, 0x00 },
> +	{ 0x3b88, 0x00 },
> +	{ 0x3b89, 0x00 },
> +	{ 0x3b8a, 0x00 },
> +	{ 0x3b8b, 0x05 },
> +	{ 0x3b8c, 0x00 },
> +	{ 0x3b8d, 0x00 },
> +	{ 0x3b8e, 0x00 },
> +	{ 0x3b8f, 0x1a },
> +	{ 0x3b94, 0x05 },
> +	{ 0x3b95, 0xf2 },
> +	{ 0x3b96, 0x40 },
> +	{ 0x3c00, 0x89 },
> +	{ 0x3c01, 0x63 },
> +	{ 0x3c02, 0x01 },
> +	{ 0x3c03, 0x00 },
> +	{ 0x3c04, 0x00 },
> +	{ 0x3c05, 0x03 },
> +	{ 0x3c06, 0x00 },
> +	{ 0x3c07, 0x06 },
> +	{ 0x3c0c, 0x01 },
> +	{ 0x3c0d, 0xd0 },
> +	{ 0x3c0e, 0x02 },
> +	{ 0x3c0f, 0x0a },
> +	{ 0x4001, 0x42 },
> +	{ 0x4004, 0x04 },
> +	{ 0x4005, 0x00 },
> +	{ 0x404e, 0x01 },
> +	{ 0x4300, 0xff },
> +	{ 0x4301, 0x00 },
> +	{ 0x4315, 0x00 },
> +	{ 0x4501, 0x48 },
> +	{ 0x4600, 0x00 },
> +	{ 0x4601, 0x4e },
> +	{ 0x4801, 0x0f },
> +	{ 0x4806, 0x0f },
> +	{ 0x4819, 0xaa },
> +	{ 0x4823, 0x3e },
> +	{ 0x4837, 0x19 },
> +	{ 0x4a0d, 0x00 },
> +	{ 0x4a47, 0x7f },
> +	{ 0x4a49, 0xf0 },
> +	{ 0x4a4b, 0x30 },
> +	{ 0x5000, 0x85 },
> +	{ 0x5001, 0x80 },
> +};
> +
> +static const struct reg_value ov7251_setting_vga_90fps[] = {
> +	{ 0x3005, 0x00 },
> +	{ 0x3012, 0xc0 },
> +	{ 0x3013, 0xd2 },
> +	{ 0x3014, 0x04 },
> +	{ 0x3016, 0x10 },
> +	{ 0x3017, 0x00 },
> +	{ 0x3018, 0x00 },
> +	{ 0x301a, 0x00 },
> +	{ 0x301b, 0x00 },
> +	{ 0x301c, 0x00 },
> +	{ 0x3023, 0x05 },
> +	{ 0x3037, 0xf0 },
> +	{ 0x3098, 0x04 }, /* pll2 pre divider */
> +	{ 0x3099, 0x28 }, /* pll2 multiplier */
> +	{ 0x309a, 0x05 }, /* pll2 sys divider */
> +	{ 0x309b, 0x04 }, /* pll2 adc divider */
> +	{ 0x309d, 0x00 }, /* pll2 divider */
> +	{ 0x30b0, 0x0a }, /* pll1 pix divider */
> +	{ 0x30b1, 0x01 }, /* pll1 divider */
> +	{ 0x30b3, 0x64 }, /* pll1 multiplier */
> +	{ 0x30b4, 0x03 }, /* pll1 pre divider */
> +	{ 0x30b5, 0x05 }, /* pll1 mipi divider */
> +	{ 0x3106, 0xda },
> +	{ 0x3503, 0x07 },
> +	{ 0x3509, 0x10 },
> +	{ 0x3600, 0x1c },
> +	{ 0x3602, 0x62 },
> +	{ 0x3620, 0xb7 },
> +	{ 0x3622, 0x04 },
> +	{ 0x3626, 0x21 },
> +	{ 0x3627, 0x30 },
> +	{ 0x3630, 0x44 },
> +	{ 0x3631, 0x35 },
> +	{ 0x3634, 0x60 },
> +	{ 0x3636, 0x00 },
> +	{ 0x3662, 0x01 },
> +	{ 0x3663, 0x70 },
> +	{ 0x3664, 0x50 },
> +	{ 0x3666, 0x0a },
> +	{ 0x3669, 0x1a },
> +	{ 0x366a, 0x00 },
> +	{ 0x366b, 0x50 },
> +	{ 0x3673, 0x01 },
> +	{ 0x3674, 0xff },
> +	{ 0x3675, 0x03 },
> +	{ 0x3705, 0xc1 },
> +	{ 0x3709, 0x40 },
> +	{ 0x373c, 0x08 },
> +	{ 0x3742, 0x00 },
> +	{ 0x3757, 0xb3 },
> +	{ 0x3788, 0x00 },
> +	{ 0x37a8, 0x01 },
> +	{ 0x37a9, 0xc0 },
> +	{ 0x3800, 0x00 },
> +	{ 0x3801, 0x04 },
> +	{ 0x3802, 0x00 },
> +	{ 0x3803, 0x04 },
> +	{ 0x3804, 0x02 },
> +	{ 0x3805, 0x8b },
> +	{ 0x3806, 0x01 },
> +	{ 0x3807, 0xeb },
> +	{ 0x3808, 0x02 }, /* width high */
> +	{ 0x3809, 0x80 }, /* width low */
> +	{ 0x380a, 0x01 }, /* height high */
> +	{ 0x380b, 0xe0 }, /* height low */
> +	{ 0x380c, 0x03 }, /* total horiz timing high */
> +	{ 0x380d, 0xa0 }, /* total horiz timing low */
> +	{ 0x380e, 0x02 }, /* total vertical timing high */
> +	{ 0x380f, 0x3c }, /* total vertical timing low */
> +	{ 0x3810, 0x00 },
> +	{ 0x3811, 0x04 },
> +	{ 0x3812, 0x00 },
> +	{ 0x3813, 0x05 },
> +	{ 0x3814, 0x11 },
> +	{ 0x3815, 0x11 },
> +	{ 0x3820, 0x40 },
> +	{ 0x3821, 0x00 },
> +	{ 0x382f, 0x0e },
> +	{ 0x3832, 0x00 },
> +	{ 0x3833, 0x05 },
> +	{ 0x3834, 0x00 },
> +	{ 0x3835, 0x0c },
> +	{ 0x3837, 0x00 },
> +	{ 0x3b80, 0x00 },
> +	{ 0x3b81, 0xa5 },
> +	{ 0x3b82, 0x10 },
> +	{ 0x3b83, 0x00 },
> +	{ 0x3b84, 0x08 },
> +	{ 0x3b85, 0x00 },
> +	{ 0x3b86, 0x01 },
> +	{ 0x3b87, 0x00 },
> +	{ 0x3b88, 0x00 },
> +	{ 0x3b89, 0x00 },
> +	{ 0x3b8a, 0x00 },
> +	{ 0x3b8b, 0x05 },
> +	{ 0x3b8c, 0x00 },
> +	{ 0x3b8d, 0x00 },
> +	{ 0x3b8e, 0x00 },
> +	{ 0x3b8f, 0x1a },
> +	{ 0x3b94, 0x05 },
> +	{ 0x3b95, 0xf2 },
> +	{ 0x3b96, 0x40 },
> +	{ 0x3c00, 0x89 },
> +	{ 0x3c01, 0x63 },
> +	{ 0x3c02, 0x01 },
> +	{ 0x3c03, 0x00 },
> +	{ 0x3c04, 0x00 },
> +	{ 0x3c05, 0x03 },
> +	{ 0x3c06, 0x00 },
> +	{ 0x3c07, 0x06 },
> +	{ 0x3c0c, 0x01 },
> +	{ 0x3c0d, 0xd0 },
> +	{ 0x3c0e, 0x02 },
> +	{ 0x3c0f, 0x0a },
> +	{ 0x4001, 0x42 },
> +	{ 0x4004, 0x04 },
> +	{ 0x4005, 0x00 },
> +	{ 0x404e, 0x01 },
> +	{ 0x4300, 0xff },
> +	{ 0x4301, 0x00 },
> +	{ 0x4315, 0x00 },
> +	{ 0x4501, 0x48 },
> +	{ 0x4600, 0x00 },
> +	{ 0x4601, 0x4e },
> +	{ 0x4801, 0x0f },
> +	{ 0x4806, 0x0f },
> +	{ 0x4819, 0xaa },
> +	{ 0x4823, 0x3e },
> +	{ 0x4837, 0x19 },
> +	{ 0x4a0d, 0x00 },
> +	{ 0x4a47, 0x7f },
> +	{ 0x4a49, 0xf0 },
> +	{ 0x4a4b, 0x30 },
> +	{ 0x5000, 0x85 },
> +	{ 0x5001, 0x80 },
> +};
> +
> +static const s64 link_freq[] = {
> +	240000000,
> +};
> +
> +static const struct ov7251_mode_info ov7251_mode_info_data[] = {
> +	{
> +		.width = 640,
> +		.height = 480,
> +		.data = ov7251_setting_vga_30fps,
> +		.data_size = ARRAY_SIZE(ov7251_setting_vga_30fps),
> +		.pixel_clock = 48000000,
> +		.link_freq = 0, /* an index in link_freq[] */
> +		.exposure_max = 1704,
> +		.exposure_def = 504,
> +		.timeperframe = {
> +			.numerator = 100,
> +			.denominator = 3000
> +		}
> +	},
> +	{
> +		.width = 640,
> +		.height = 480,
> +		.data = ov7251_setting_vga_60fps,
> +		.data_size = ARRAY_SIZE(ov7251_setting_vga_60fps),
> +		.pixel_clock = 48000000,
> +		.link_freq = 0, /* an index in link_freq[] */
> +		.exposure_max = 840,
> +		.exposure_def = 504,
> +		.timeperframe = {
> +			.numerator = 100,
> +			.denominator = 6014
> +		}
> +	},
> +	{
> +		.width = 640,
> +		.height = 480,
> +		.data = ov7251_setting_vga_90fps,
> +		.data_size = ARRAY_SIZE(ov7251_setting_vga_90fps),
> +		.pixel_clock = 48000000,
> +		.link_freq = 0, /* an index in link_freq[] */
> +		.exposure_max = 552,
> +		.exposure_def = 504,
> +		.timeperframe = {
> +			.numerator = 100,
> +			.denominator = 9043
> +		}
> +	},
> +};
> +
> +static int ov7251_regulators_enable(struct ov7251 *ov7251)
> +{
> +	int ret;
> +
> +	ret = regulator_enable(ov7251->io_regulator);

How about regulator_bulk_enable() here, and bulk_disable below?

> +	if (ret < 0) {
> +		dev_err(ov7251->dev, "set io voltage failed\n");
> +		return ret;
> +	}
> +
> +	ret = regulator_enable(ov7251->analog_regulator);
> +	if (ret) {
> +		dev_err(ov7251->dev, "set analog voltage failed\n");
> +		goto err_disable_io;
> +	}
> +
> +	ret = regulator_enable(ov7251->core_regulator);
> +	if (ret) {
> +		dev_err(ov7251->dev, "set core voltage failed\n");
> +		goto err_disable_analog;
> +	}
> +
> +	return 0;
> +
> +err_disable_analog:
> +	regulator_disable(ov7251->analog_regulator);
> +err_disable_io:
> +	regulator_disable(ov7251->io_regulator);
> +
> +	return ret;
> +}
> +
> +static void ov7251_regulators_disable(struct ov7251 *ov7251)
> +{
> +	int ret;
> +
> +	ret = regulator_disable(ov7251->core_regulator);
> +	if (ret < 0)
> +		dev_err(ov7251->dev, "core regulator disable failed\n");
> +
> +	ret = regulator_disable(ov7251->analog_regulator);
> +	if (ret < 0)
> +		dev_err(ov7251->dev, "analog regulator disable failed\n");
> +
> +	ret = regulator_disable(ov7251->io_regulator);
> +	if (ret < 0)
> +		dev_err(ov7251->dev, "io regulator disable failed\n");
> +}
> +
> +static int ov7251_write_reg(struct ov7251 *ov7251, u16 reg, u8 val)
> +{
> +	u8 regbuf[3];
> +	int ret;
> +
> +	regbuf[0] = reg >> 8;
> +	regbuf[1] = reg & 0xff;
> +	regbuf[2] = val;
> +
> +	ret = i2c_master_send(ov7251->i2c_client, regbuf, 3);
> +	if (ret < 0) {
> +		dev_err(ov7251->dev, "%s: write reg error %d: reg=%x, val=%x\n",
> +			__func__, ret, reg, val);
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static int ov7251_read_reg(struct ov7251 *ov7251, u16 reg, u8 *val)
> +{
> +	u8 regbuf[2];
> +	int ret;
> +
> +	regbuf[0] = reg >> 8;
> +	regbuf[1] = reg & 0xff;
> +
> +	ret = i2c_master_send(ov7251->i2c_client, regbuf, 2);
> +	if (ret < 0) {
> +		dev_err(ov7251->dev, "%s: write reg error %d: reg=%x\n",
> +			__func__, ret, reg);
> +		return ret;
> +	}
> +
> +	ret = i2c_master_recv(ov7251->i2c_client, val, 1);
> +	if (ret < 0) {
> +		dev_err(ov7251->dev, "%s: read reg error %d: reg=%x\n",
> +			__func__, ret, reg);
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static int ov7251_set_exposure(struct ov7251 *ov7251, s32 exposure)
> +{
> +	int ret;
> +
> +	ret = ov7251_write_reg(ov7251, OV7251_AEC_EXPO_0,
> +			       (exposure & 0xf000) >> 12);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = ov7251_write_reg(ov7251, OV7251_AEC_EXPO_1,
> +			       (exposure & 0x0ff0) >> 4);
> +	if (ret < 0)
> +		return ret;
> +
> +	return ov7251_write_reg(ov7251, OV7251_AEC_EXPO_2,
> +				(exposure & 0x000f) << 4);

It's not a good idea to access multi-octet registers separately. Depending
on the hardware implementation, the hardware could latch the value in the
middle of an update. This is only an issue during streaming in practice
though.

> +}
> +
> +static int ov7251_set_gain(struct ov7251 *ov7251, s32 gain)
> +{
> +	int ret;
> +
> +	ret = ov7251_write_reg(ov7251, OV7251_AEC_AGC_ADJ_0,
> +			       (gain & 0x0300) >> 8);
> +	if (ret < 0)
> +		return ret;
> +
> +	return ov7251_write_reg(ov7251, OV7251_AEC_AGC_ADJ_1, gain & 0xff);
> +}
> +
> +static int ov7251_set_register_array(struct ov7251 *ov7251,
> +				     const struct reg_value *settings,
> +				     unsigned int num_settings)
> +{
> +	unsigned int i;
> +	int ret;
> +
> +	for (i = 0; i < num_settings; ++i, ++settings) {
> +		ret = ov7251_write_reg(ov7251, settings->reg, settings->val);
> +		if (ret < 0)
> +			return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static int ov7251_set_power_on(struct ov7251 *ov7251)
> +{
> +	int ret;
> +
> +	ret = ov7251_regulators_enable(ov7251);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = clk_prepare_enable(ov7251->xclk);
> +	if (ret < 0) {
> +		dev_err(ov7251->dev, "clk prepare enable failed\n");
> +		ov7251_regulators_disable(ov7251);
> +		return ret;
> +	}
> +
> +	gpiod_set_value_cansleep(ov7251->enable_gpio, 1);
> +
> +	usleep_range(3000, 4000); /* 65536 / 24MHz = 2.73ms */

What's the minimum time required between lifting XSHUTDOWN and I²C access?
Could you calculate the value based on the external clock frequency
instead?

> +
> +	return 0;
> +}
> +
> +static void ov7251_set_power_off(struct ov7251 *ov7251)
> +{
> +	clk_disable_unprepare(ov7251->xclk);
> +	gpiod_set_value_cansleep(ov7251->enable_gpio, 0);
> +	ov7251_regulators_disable(ov7251);
> +}
> +
> +static int ov7251_s_power(struct v4l2_subdev *sd, int on)
> +{
> +	struct ov7251 *ov7251 = to_ov7251(sd);
> +	int ret = 0;
> +
> +	mutex_lock(&ov7251->power_lock);
> +
> +	/*
> +	 * If the power state is modified from 0 to 1 or from 1 to 0,
> +	 * update the power state.
> +	 */
> +	if (ov7251->power_on == !on) {
> +		if (on) {
> +			ret = ov7251_set_power_on(ov7251);
> +			if (ret < 0)
> +				goto exit;
> +
> +			ret = ov7251_set_register_array(ov7251,
> +					ov7251_global_init_setting,
> +					ARRAY_SIZE(ov7251_global_init_setting));
> +			if (ret < 0) {
> +				dev_err(ov7251->dev,
> +					"could not set init registers\n");
> +				ov7251_set_power_off(ov7251);
> +				goto exit;
> +			}
> +
> +			ov7251->power_on = true;
> +		} else {
> +			ov7251_set_power_off(ov7251);
> +			ov7251->power_on = false;
> +		}
> +	}
> +
> +exit:
> +	mutex_unlock(&ov7251->power_lock);
> +
> +	return ret;
> +}
> +
> +static int ov7251_set_hflip(struct ov7251 *ov7251, s32 value)
> +{
> +	u8 val = ov7251->timing_format2;
> +	int ret;
> +
> +	if (value)
> +		val |= OV7251_TIMING_FORMAT2_MIRROR;
> +	else
> +		val &= ~OV7251_TIMING_FORMAT2_MIRROR;
> +
> +	ret = ov7251_write_reg(ov7251, OV7251_TIMING_FORMAT2, val);
> +	if (!ret)
> +		ov7251->timing_format2 = val;
> +
> +	return ret;
> +}
> +
> +static int ov7251_set_vflip(struct ov7251 *ov7251, s32 value)
> +{
> +	u8 val = ov7251->timing_format1;
> +	int ret;
> +
> +	if (value)
> +		val |= OV7251_TIMING_FORMAT1_VFLIP;
> +	else
> +		val &= ~OV7251_TIMING_FORMAT1_VFLIP;
> +
> +	ret = ov7251_write_reg(ov7251, OV7251_TIMING_FORMAT1, val);
> +	if (!ret)
> +		ov7251->timing_format1 = val;
> +
> +	return ret;
> +}
> +
> +static int ov7251_set_test_pattern(struct ov7251 *ov7251, s32 value)
> +{
> +	u8 val = ov7251->pre_isp_00;
> +	int ret;
> +
> +	if (value)
> +		val |= OV7251_PRE_ISP_00_TEST_PATTERN;
> +	else
> +		val &= ~OV7251_PRE_ISP_00_TEST_PATTERN;
> +
> +	ret = ov7251_write_reg(ov7251, OV7251_PRE_ISP_00, val);
> +	if (!ret)
> +		ov7251->pre_isp_00 = val;
> +
> +	return ret;
> +}
> +
> +static const char * const ov7251_test_pattern_menu[] = {
> +	"Disabled",
> +	"Vertical Pattern Bars",
> +};
> +
> +static int ov7251_s_ctrl(struct v4l2_ctrl *ctrl)
> +{
> +	struct ov7251 *ov7251 = container_of(ctrl->handler,
> +					     struct ov7251, ctrls);
> +	int ret;
> +
> +	mutex_lock(&ov7251->power_lock);
> +	if (!ov7251->power_on) {
> +		mutex_unlock(&ov7251->power_lock);
> +		return 0;
> +	}
> +
> +	switch (ctrl->id) {
> +	case V4L2_CID_EXPOSURE:
> +		ret = ov7251_set_exposure(ov7251, ctrl->val);
> +		break;
> +	case V4L2_CID_GAIN:
> +		ret = ov7251_set_gain(ov7251, ctrl->val);
> +		break;
> +	case V4L2_CID_TEST_PATTERN:
> +		ret = ov7251_set_test_pattern(ov7251, ctrl->val);
> +		break;
> +	case V4L2_CID_HFLIP:
> +		ret = ov7251_set_hflip(ov7251, ctrl->val);
> +		break;
> +	case V4L2_CID_VFLIP:
> +		ret = ov7251_set_vflip(ov7251, ctrl->val);
> +		break;
> +	default:
> +		ret = -EINVAL;
> +		break;
> +	}
> +
> +	mutex_unlock(&ov7251->power_lock);
> +
> +	return ret;
> +}
> +
> +static const struct v4l2_ctrl_ops ov7251_ctrl_ops = {
> +	.s_ctrl = ov7251_s_ctrl,
> +};
> +
> +static int ov7251_enum_mbus_code(struct v4l2_subdev *sd,
> +				 struct v4l2_subdev_pad_config *cfg,
> +				 struct v4l2_subdev_mbus_code_enum *code)
> +{
> +	if (code->index > 0)
> +		return -EINVAL;
> +
> +	code->code = MEDIA_BUS_FMT_SBGGR10_1X10;
> +
> +	return 0;
> +}
> +
> +static int ov7251_enum_frame_size(struct v4l2_subdev *subdev,
> +				  struct v4l2_subdev_pad_config *cfg,
> +				  struct v4l2_subdev_frame_size_enum *fse)
> +{
> +	if (fse->code != MEDIA_BUS_FMT_SBGGR10_1X10)

Can the flip controls affect the media bus code? Either take this into
account or remove flip controls.

> +		return -EINVAL;
> +
> +	if (fse->index >= ARRAY_SIZE(ov7251_mode_info_data))
> +		return -EINVAL;
> +
> +	fse->min_width = ov7251_mode_info_data[fse->index].width;
> +	fse->max_width = ov7251_mode_info_data[fse->index].width;
> +	fse->min_height = ov7251_mode_info_data[fse->index].height;
> +	fse->max_height = ov7251_mode_info_data[fse->index].height;
> +
> +	return 0;
> +}
> +
> +static int ov7251_enum_frame_ival(struct v4l2_subdev *subdev,
> +				  struct v4l2_subdev_pad_config *cfg,
> +				  struct v4l2_subdev_frame_interval_enum *fie)
> +{
> +	int index = fie->index;
> +	int i;
> +
> +	for (i = 0; i < ARRAY_SIZE(ov7251_mode_info_data); i++) {
> +		if (fie->width != ov7251_mode_info_data[i].width ||
> +		    fie->height != ov7251_mode_info_data[i].height)
> +			continue;
> +
> +		if (index-- == 0) {
> +			fie->interval = ov7251_mode_info_data[i].timeperframe;
> +			return 0;
> +		}
> +	}
> +
> +	return -EINVAL;
> +}
> +
> +static struct v4l2_mbus_framefmt *
> +__ov7251_get_pad_format(struct ov7251 *ov7251,
> +			struct v4l2_subdev_pad_config *cfg,
> +			unsigned int pad,
> +			enum v4l2_subdev_format_whence which)
> +{
> +	switch (which) {
> +	case V4L2_SUBDEV_FORMAT_TRY:
> +		return v4l2_subdev_get_try_format(&ov7251->sd, cfg, pad);
> +	case V4L2_SUBDEV_FORMAT_ACTIVE:
> +		return &ov7251->fmt;
> +	default:
> +		return NULL;
> +	}
> +}
> +
> +static int ov7251_get_format(struct v4l2_subdev *sd,
> +			     struct v4l2_subdev_pad_config *cfg,
> +			     struct v4l2_subdev_format *format)
> +{
> +	struct ov7251 *ov7251 = to_ov7251(sd);
> +
> +	format->format = *__ov7251_get_pad_format(ov7251, cfg, format->pad,
> +						  format->which);
> +	return 0;
> +}
> +
> +static struct v4l2_rect *
> +__ov7251_get_pad_crop(struct ov7251 *ov7251, struct v4l2_subdev_pad_config *cfg,
> +		      unsigned int pad, enum v4l2_subdev_format_whence which)
> +{
> +	switch (which) {
> +	case V4L2_SUBDEV_FORMAT_TRY:
> +		return v4l2_subdev_get_try_crop(&ov7251->sd, cfg, pad);
> +	case V4L2_SUBDEV_FORMAT_ACTIVE:
> +		return &ov7251->crop;
> +	default:
> +		return NULL;
> +	}
> +}
> +
> +#define TIMEPERFRAME_AVG_FPS(t)						\
> +	(((t).denominator + ((t).numerator >> 1)) / (t).numerator)
> +
> +static const struct ov7251_mode_info *
> +ov7251_find_mode_by_ival(struct ov7251 *ov7251, struct v4l2_fract *timeperframe)
> +{
> +	const struct ov7251_mode_info *mode = ov7251->current_mode;
> +	int fps_req = TIMEPERFRAME_AVG_FPS(*timeperframe);
> +	unsigned int max_dist_match = (unsigned int) -1;
> +	int i, n = 0;
> +
> +	for (i = 0; i < ARRAY_SIZE(ov7251_mode_info_data); i++) {
> +		unsigned int dist;
> +		int fps_tmp;
> +
> +		if (mode->width != ov7251_mode_info_data[i].width ||
> +		    mode->height != ov7251_mode_info_data[i].height)
> +			continue;
> +
> +		fps_tmp = TIMEPERFRAME_AVG_FPS(
> +					ov7251_mode_info_data[i].timeperframe);
> +
> +		dist = abs(fps_req - fps_tmp);
> +
> +		if (dist < max_dist_match) {
> +			n = i;
> +			max_dist_match = dist;
> +		}
> +	}
> +
> +	return &ov7251_mode_info_data[n];
> +}
> +
> +static int ov7251_set_format(struct v4l2_subdev *sd,
> +			     struct v4l2_subdev_pad_config *cfg,
> +			     struct v4l2_subdev_format *format)
> +{
> +	struct ov7251 *ov7251 = to_ov7251(sd);
> +	struct v4l2_mbus_framefmt *__format;
> +	struct v4l2_rect *__crop;
> +	const struct ov7251_mode_info *new_mode;
> +	int ret;
> +

Does setting the mode need to be serialised? Right now it doesn't seem to
be. There seem to be dependencies between the controls as well as the
format...

Same for s_stream, to avoid the format to be changed while starting
streaming.

> +	__crop = __ov7251_get_pad_crop(ov7251, cfg, format->pad,
> +			format->which);
> +
> +	new_mode = v4l2_find_nearest_size(ov7251_mode_info_data,
> +			       width, height,
> +			       format->format.width, format->format.height);
> +
> +	__crop->width = new_mode->width;
> +	__crop->height = new_mode->height;
> +
> +	if (format->which == V4L2_SUBDEV_FORMAT_ACTIVE) {
> +		ret = v4l2_ctrl_s_ctrl_int64(ov7251->pixel_clock,
> +					     new_mode->pixel_clock);
> +		if (ret < 0)
> +			return ret;
> +
> +		ret = v4l2_ctrl_s_ctrl(ov7251->link_freq,
> +				       new_mode->link_freq);
> +		if (ret < 0)
> +			return ret;
> +
> +		ret = v4l2_ctrl_modify_range(ov7251->exposure,
> +					     1, new_mode->exposure_max,
> +					     1, new_mode->exposure_def);
> +		if (ret < 0)
> +			return ret;
> +
> +		ret = v4l2_ctrl_s_ctrl(ov7251->exposure,
> +				       new_mode->exposure_def);
> +		if (ret < 0)
> +			return ret;
> +
> +
> +		ret = v4l2_ctrl_s_ctrl(ov7251->gain, 16);
> +		if (ret < 0)
> +			return ret;
> +
> +		ov7251->current_mode = new_mode;
> +	}
> +
> +	__format = __ov7251_get_pad_format(ov7251, cfg, format->pad,
> +			format->which);
> +	__format->width = __crop->width;
> +	__format->height = __crop->height;
> +	__format->code = MEDIA_BUS_FMT_SBGGR10_1X10;
> +	__format->field = V4L2_FIELD_NONE;
> +	__format->colorspace = V4L2_COLORSPACE_SRGB;
> +	__format->ycbcr_enc = V4L2_MAP_YCBCR_ENC_DEFAULT(__format->colorspace);
> +	__format->quantization = V4L2_MAP_QUANTIZATION_DEFAULT(true,
> +				__format->colorspace, __format->ycbcr_enc);
> +	__format->xfer_func = V4L2_MAP_XFER_FUNC_DEFAULT(__format->colorspace);
> +
> +	format->format = *__format;
> +
> +	return 0;
> +}
> +
> +static int ov7251_entity_init_cfg(struct v4l2_subdev *subdev,
> +				  struct v4l2_subdev_pad_config *cfg)
> +{
> +	struct v4l2_subdev_format fmt = { 0 };
> +
> +	fmt.which = cfg ? V4L2_SUBDEV_FORMAT_TRY : V4L2_SUBDEV_FORMAT_ACTIVE;
> +	fmt.format.width = 640;
> +	fmt.format.height = 480;
> +
> +	ov7251_set_format(subdev, cfg, &fmt);
> +
> +	return 0;
> +}
> +
> +static int ov7251_get_selection(struct v4l2_subdev *sd,
> +			   struct v4l2_subdev_pad_config *cfg,
> +			   struct v4l2_subdev_selection *sel)
> +{
> +	struct ov7251 *ov7251 = to_ov7251(sd);
> +
> +	if (sel->target != V4L2_SEL_TGT_CROP)
> +		return -EINVAL;
> +
> +	sel->r = *__ov7251_get_pad_crop(ov7251, cfg, sel->pad,
> +					sel->which);
> +	return 0;
> +}
> +
> +static int ov7251_s_stream(struct v4l2_subdev *subdev, int enable)
> +{
> +	struct ov7251 *ov7251 = to_ov7251(subdev);
> +	int ret;
> +
> +	if (enable) {
> +		ret = ov7251_set_register_array(ov7251,
> +					ov7251->current_mode->data,
> +					ov7251->current_mode->data_size);
> +		if (ret < 0) {
> +			dev_err(ov7251->dev, "could not set mode %dx%d\n",
> +				ov7251->current_mode->width,
> +				ov7251->current_mode->height);
> +			return ret;
> +		}
> +		ret = v4l2_ctrl_handler_setup(&ov7251->ctrls);
> +		if (ret < 0) {
> +			dev_err(ov7251->dev, "could not sync v4l2 controls\n");
> +			return ret;
> +		}
> +		ret = ov7251_write_reg(ov7251, OV7251_SC_MODE_SELECT,
> +				       OV7251_SC_MODE_SELECT_STREAMING);
> +		if (ret < 0)
> +			return ret;
> +	} else {
> +		ret = ov7251_write_reg(ov7251, OV7251_SC_MODE_SELECT,
> +				       OV7251_SC_MODE_SELECT_SW_STANDBY);
> +		if (ret < 0)
> +			return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static int ov7251_get_frame_interval(struct v4l2_subdev *subdev,
> +				     struct v4l2_subdev_frame_interval *fi)
> +{
> +	struct ov7251 *ov7251 = to_ov7251(subdev);
> +
> +	fi->interval = ov7251->current_mode->timeperframe;
> +
> +	return 0;
> +}
> +
> +static int ov7251_set_frame_interval(struct v4l2_subdev *subdev,
> +				     struct v4l2_subdev_frame_interval *fi)
> +{
> +	struct ov7251 *ov7251 = to_ov7251(subdev);
> +	const struct ov7251_mode_info *new_mode;
> +
> +	new_mode = ov7251_find_mode_by_ival(ov7251, &fi->interval);
> +
> +	if (new_mode != ov7251->current_mode) {
> +		int ret;
> +
> +		ret = v4l2_ctrl_s_ctrl_int64(ov7251->pixel_clock,
> +					     new_mode->pixel_clock);
> +		if (ret < 0)
> +			return ret;
> +
> +		ret = v4l2_ctrl_s_ctrl(ov7251->link_freq,
> +				       new_mode->link_freq);
> +		if (ret < 0)
> +			return ret;
> +
> +		ret = v4l2_ctrl_modify_range(ov7251->exposure,
> +					     1, new_mode->exposure_max,
> +					     1, new_mode->exposure_def);
> +		if (ret < 0)
> +			return ret;
> +
> +		ret = v4l2_ctrl_s_ctrl(ov7251->exposure,
> +				       new_mode->exposure_def);
> +		if (ret < 0)
> +			return ret;
> +
> +		ret = v4l2_ctrl_s_ctrl(ov7251->gain, 16);
> +		if (ret < 0)
> +			return ret;
> +
> +		ov7251->current_mode = new_mode;
> +	}
> +
> +	fi->interval = ov7251->current_mode->timeperframe;
> +
> +	return 0;
> +}
> +
> +static const struct v4l2_subdev_core_ops ov7251_core_ops = {
> +	.s_power = ov7251_s_power,
> +};
> +
> +static const struct v4l2_subdev_video_ops ov7251_video_ops = {
> +	.s_stream = ov7251_s_stream,
> +	.g_frame_interval = ov7251_get_frame_interval,
> +	.s_frame_interval = ov7251_set_frame_interval,
> +};
> +
> +static const struct v4l2_subdev_pad_ops ov7251_subdev_pad_ops = {
> +	.init_cfg = ov7251_entity_init_cfg,
> +	.enum_mbus_code = ov7251_enum_mbus_code,
> +	.enum_frame_size = ov7251_enum_frame_size,
> +	.enum_frame_interval = ov7251_enum_frame_ival,
> +	.get_fmt = ov7251_get_format,
> +	.set_fmt = ov7251_set_format,
> +	.get_selection = ov7251_get_selection,
> +};
> +
> +static const struct v4l2_subdev_ops ov7251_subdev_ops = {
> +	.core = &ov7251_core_ops,
> +	.video = &ov7251_video_ops,
> +	.pad = &ov7251_subdev_pad_ops,
> +};
> +
> +static int ov7251_probe(struct i2c_client *client,
> +			const struct i2c_device_id *id)
> +{
> +	struct device *dev = &client->dev;
> +	struct fwnode_handle *endpoint;
> +	struct ov7251 *ov7251;
> +	u8 chip_id_high, chip_id_low, chip_rev;
> +	u32 xclk_freq;
> +	int ret;
> +
> +	ov7251 = devm_kzalloc(dev, sizeof(struct ov7251), GFP_KERNEL);
> +	if (!ov7251)
> +		return -ENOMEM;
> +
> +	ov7251->i2c_client = client;
> +	ov7251->dev = dev;
> +
> +	endpoint = fwnode_graph_get_next_endpoint(dev_fwnode(dev), NULL);
> +	if (!endpoint) {
> +		dev_err(dev, "endpoint node not found\n");
> +		return -EINVAL;
> +	}
> +
> +	ret = v4l2_fwnode_endpoint_parse(endpoint, &ov7251->ep);
> +	fwnode_handle_put(endpoint);
> +	if (ret < 0) {
> +		dev_err(dev, "parsing endpoint node failed\n");
> +		return ret;
> +	}
> +
> +	if (ov7251->ep.bus_type != V4L2_MBUS_CSI2) {
> +		dev_err(dev, "invalid bus type (%u), must be CSI2 (%u)\n",
> +			ov7251->ep.bus_type, V4L2_MBUS_CSI2);
> +		return -EINVAL;
> +	}
> +
> +	/* get system clock (xclk) */
> +	ov7251->xclk = devm_clk_get(dev, "xclk");
> +	if (IS_ERR(ov7251->xclk)) {
> +		dev_err(dev, "could not get xclk");
> +		return PTR_ERR(ov7251->xclk);
> +	}
> +
> +	ret = of_property_read_u32(dev->of_node, "clock-frequency", &xclk_freq);
> +	if (ret) {
> +		dev_err(dev, "could not get xclk frequency\n");
> +		return ret;
> +	}
> +
> +	/* external clock must be 24MHz, allow 1% tolerance */
> +	if (xclk_freq < 23760000 || xclk_freq > 24240000) {
> +		dev_err(dev, "external clock frequency %u is not supported\n",
> +			xclk_freq);
> +		return -EINVAL;
> +	}
> +
> +	ret = clk_set_rate(ov7251->xclk, xclk_freq);
> +	if (ret) {
> +		dev_err(dev, "could not set xclk frequency\n");
> +		return ret;
> +	}
> +
> +	ov7251->io_regulator = devm_regulator_get(dev, "vdddo");
> +	if (IS_ERR(ov7251->io_regulator)) {
> +		dev_err(dev, "cannot get io regulator\n");
> +		return PTR_ERR(ov7251->io_regulator);
> +	}
> +
> +	ret = regulator_set_voltage(ov7251->io_regulator,
> +				    OV7251_VOLTAGE_DIGITAL_IO,
> +				    OV7251_VOLTAGE_DIGITAL_IO);

Shouldn't this be accounted for in DT? I have to say I'm not an expert in
this area, still the only other driver doing this is ov5645. And it's
written by you. :-)

> +	if (ret < 0) {
> +		dev_err(dev, "cannot set io voltage\n");
> +		return ret;
> +	}
> +
> +	ov7251->core_regulator = devm_regulator_get(dev, "vddd");
> +	if (IS_ERR(ov7251->core_regulator)) {
> +		dev_err(dev, "cannot get core regulator\n");
> +		return PTR_ERR(ov7251->core_regulator);
> +	}
> +
> +	ret = regulator_set_voltage(ov7251->core_regulator,
> +				    OV7251_VOLTAGE_DIGITAL_CORE,
> +				    OV7251_VOLTAGE_DIGITAL_CORE);
> +	if (ret < 0) {
> +		dev_err(dev, "cannot set core voltage\n");
> +		return ret;
> +	}
> +
> +	ov7251->analog_regulator = devm_regulator_get(dev, "vdda");
> +	if (IS_ERR(ov7251->analog_regulator)) {
> +		dev_err(dev, "cannot get analog regulator\n");
> +		return PTR_ERR(ov7251->analog_regulator);
> +	}
> +
> +	ret = regulator_set_voltage(ov7251->analog_regulator,
> +				    OV7251_VOLTAGE_ANALOG,
> +				    OV7251_VOLTAGE_ANALOG);
> +	if (ret < 0) {
> +		dev_err(dev, "cannot set analog voltage\n");
> +		return ret;
> +	}
> +
> +	ov7251->enable_gpio = devm_gpiod_get(dev, "enable", GPIOD_OUT_HIGH);
> +	if (IS_ERR(ov7251->enable_gpio)) {
> +		dev_err(dev, "cannot get enable gpio\n");
> +		return PTR_ERR(ov7251->enable_gpio);
> +	}
> +
> +	mutex_init(&ov7251->power_lock);
> +
> +	v4l2_ctrl_handler_init(&ov7251->ctrls, 7);
> +	v4l2_ctrl_new_std(&ov7251->ctrls, &ov7251_ctrl_ops,
> +			  V4L2_CID_HFLIP, 0, 1, 1, 0);
> +	v4l2_ctrl_new_std(&ov7251->ctrls, &ov7251_ctrl_ops,
> +			  V4L2_CID_VFLIP, 0, 1, 1, 0);
> +	ov7251->exposure = v4l2_ctrl_new_std(&ov7251->ctrls, &ov7251_ctrl_ops,
> +					     V4L2_CID_EXPOSURE, 1, 32, 1, 32);
> +	ov7251->gain = v4l2_ctrl_new_std(&ov7251->ctrls, &ov7251_ctrl_ops,
> +					 V4L2_CID_GAIN, 16, 1023, 1, 16);
> +	v4l2_ctrl_new_std_menu_items(&ov7251->ctrls, &ov7251_ctrl_ops,
> +				     V4L2_CID_TEST_PATTERN,
> +				     ARRAY_SIZE(ov7251_test_pattern_menu) - 1,
> +				     0, 0, ov7251_test_pattern_menu);
> +	ov7251->pixel_clock = v4l2_ctrl_new_std(&ov7251->ctrls,
> +						&ov7251_ctrl_ops,
> +						V4L2_CID_PIXEL_RATE,
> +						1, INT_MAX, 1, 1);
> +	ov7251->link_freq = v4l2_ctrl_new_int_menu(&ov7251->ctrls,
> +						   &ov7251_ctrl_ops,
> +						   V4L2_CID_LINK_FREQ,
> +						   ARRAY_SIZE(link_freq) - 1,
> +						   0, link_freq);
> +	if (ov7251->link_freq)
> +		ov7251->link_freq->flags |= V4L2_CTRL_FLAG_READ_ONLY;
> +
> +	ov7251->sd.ctrl_handler = &ov7251->ctrls;
> +
> +	if (ov7251->ctrls.error) {
> +		dev_err(dev, "%s: control initialization error %d\n",
> +		       __func__, ov7251->ctrls.error);
> +		ret = ov7251->ctrls.error;
> +		goto free_ctrl;
> +	}
> +
> +	v4l2_i2c_subdev_init(&ov7251->sd, client, &ov7251_subdev_ops);
> +	ov7251->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
> +	ov7251->pad.flags = MEDIA_PAD_FL_SOURCE;
> +	ov7251->sd.dev = &client->dev;
> +	ov7251->sd.entity.function = MEDIA_ENT_F_CAM_SENSOR;
> +
> +	ret = media_entity_pads_init(&ov7251->sd.entity, 1, &ov7251->pad);
> +	if (ret < 0) {
> +		dev_err(dev, "could not register media entity\n");
> +		goto free_ctrl;
> +	}
> +
> +	ret = ov7251_s_power(&ov7251->sd, true);
> +	if (ret < 0) {
> +		dev_err(dev, "could not power up OV7251\n");
> +		goto free_entity;
> +	}
> +
> +	ret = ov7251_read_reg(ov7251, OV7251_CHIP_ID_HIGH, &chip_id_high);
> +	if (ret < 0 || chip_id_high != OV7251_CHIP_ID_HIGH_BYTE) {
> +		dev_err(dev, "could not read ID high\n");
> +		ret = -ENODEV;
> +		goto power_down;
> +	}
> +	ret = ov7251_read_reg(ov7251, OV7251_CHIP_ID_LOW, &chip_id_low);
> +	if (ret < 0 || chip_id_low != OV7251_CHIP_ID_LOW_BYTE) {
> +		dev_err(dev, "could not read ID low\n");
> +		ret = -ENODEV;
> +		goto power_down;
> +	}
> +
> +	ret = ov7251_read_reg(ov7251, OV7251_SC_GP_IO_IN1, &chip_rev);
> +	if (ret < 0) {
> +		dev_err(dev, "could not read revision\n");
> +		ret = -ENODEV;
> +		goto power_down;
> +	}
> +	chip_rev >>= 4;
> +
> +	dev_info(dev, "OV7251 revision %x (%s) detected at address 0x%02x\n",
> +		 chip_rev,
> +		 chip_rev == 0x4 ? "1A / 1B" :
> +		 chip_rev == 0x5 ? "1C / 1D" :
> +		 chip_rev == 0x6 ? "1E" :
> +		 chip_rev == 0x7 ? "1F" : "unknown",
> +		 client->addr);
> +
> +	ret = ov7251_read_reg(ov7251, OV7251_PRE_ISP_00,
> +			      &ov7251->pre_isp_00);
> +	if (ret < 0) {
> +		dev_err(dev, "could not read test pattern value\n");
> +		ret = -ENODEV;
> +		goto power_down;
> +	}
> +
> +	ret = ov7251_read_reg(ov7251, OV7251_TIMING_FORMAT1,
> +			      &ov7251->timing_format1);
> +	if (ret < 0) {
> +		dev_err(dev, "could not read vflip value\n");
> +		ret = -ENODEV;
> +		goto power_down;
> +	}
> +
> +	ret = ov7251_read_reg(ov7251, OV7251_TIMING_FORMAT2,
> +			      &ov7251->timing_format2);
> +	if (ret < 0) {
> +		dev_err(dev, "could not read hflip value\n");
> +		ret = -ENODEV;
> +		goto power_down;
> +	}
> +
> +	ov7251_s_power(&ov7251->sd, false);
> +
> +	ret = v4l2_async_register_subdev(&ov7251->sd);
> +	if (ret < 0) {
> +		dev_err(dev, "could not register v4l2 device\n");
> +		goto free_entity;
> +	}
> +
> +	ov7251_entity_init_cfg(&ov7251->sd, NULL);
> +
> +	return 0;
> +
> +power_down:
> +	ov7251_s_power(&ov7251->sd, false);
> +free_entity:
> +	media_entity_cleanup(&ov7251->sd.entity);
> +free_ctrl:
> +	v4l2_ctrl_handler_free(&ov7251->ctrls);
> +	mutex_destroy(&ov7251->power_lock);
> +
> +	return ret;
> +}
> +
> +static int ov7251_remove(struct i2c_client *client)
> +{
> +	struct v4l2_subdev *sd = i2c_get_clientdata(client);
> +	struct ov7251 *ov7251 = to_ov7251(sd);
> +
> +	v4l2_async_unregister_subdev(&ov7251->sd);
> +	media_entity_cleanup(&ov7251->sd.entity);
> +	v4l2_ctrl_handler_free(&ov7251->ctrls);
> +	mutex_destroy(&ov7251->power_lock);
> +
> +	return 0;
> +}
> +
> +static const struct i2c_device_id ov7251_id[] = {
> +	{ "ov7251", 0 },
> +	{}
> +};
> +MODULE_DEVICE_TABLE(i2c, ov7251_id);
> +
> +static const struct of_device_id ov7251_of_match[] = {
> +	{ .compatible = "ovti,ov7251" },
> +	{ /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, ov7251_of_match);
> +
> +static struct i2c_driver ov7251_i2c_driver = {
> +	.driver = {
> +		.of_match_table = of_match_ptr(ov7251_of_match),
> +		.name  = "ov7251",
> +	},
> +	.probe  = ov7251_probe,
> +	.remove = ov7251_remove,
> +	.id_table = ov7251_id,
> +};
> +
> +module_i2c_driver(ov7251_i2c_driver);
> +
> +MODULE_DESCRIPTION("Omnivision OV7251 Camera Driver");
> +MODULE_AUTHOR("Todor Tomov <todor.tomov@linaro.org>");
> +MODULE_LICENSE("GPL v2");
Todor Tomov April 17, 2018, 3:32 p.m. UTC | #8
Hi Sakari,

Thank you for the review.

On 29.03.2018 14:51, Sakari Ailus wrote:
> Hi Todor,
> 
> Thanks for the patch. A few quick comments below...
> 
> On Fri, Mar 23, 2018 at 12:14:20PM +0800, Todor Tomov wrote:
>> The ov7251 sensor is a 1/7.5-Inch B&W VGA (640x480) CMOS Digital Image
>> Sensor from Omnivision.
>>
>> The driver supports the following modes:
>> - 640x480 30fps
>> - 640x480 60fps
>> - 640x480 90fps
>>
>> Output format is MIPI RAW 10.
>>
>> The driver supports configuration via user controls for:
>> - exposure and gain;
>> - horizontal and vertical flip;
>> - test pattern.
>>
>> Signed-off-by: Todor Tomov <todor.tomov@linaro.org>
>> ---
>>  drivers/media/i2c/Kconfig  |   13 +
>>  drivers/media/i2c/Makefile |    1 +
>>  drivers/media/i2c/ov7251.c | 1494 ++++++++++++++++++++++++++++++++++++++++++++
>>  3 files changed, 1508 insertions(+)
>>  create mode 100644 drivers/media/i2c/ov7251.c
>>
>> diff --git a/drivers/media/i2c/Kconfig b/drivers/media/i2c/Kconfig
>> index 541f0d28..89aecb3 100644
>> --- a/drivers/media/i2c/Kconfig
>> +++ b/drivers/media/i2c/Kconfig
>> @@ -688,6 +688,19 @@ config VIDEO_OV5695
>>  	  To compile this driver as a module, choose M here: the
>>  	  module will be called ov5695.
>>  
>> +config VIDEO_OV7251
>> +	tristate "OmniVision OV7251 sensor support"
>> +	depends on OF
>> +	depends on I2C && VIDEO_V4L2 && VIDEO_V4L2_SUBDEV_API
>> +	depends on MEDIA_CAMERA_SUPPORT
>> +	select V4L2_FWNODE
>> +	---help---
>> +	  This is a Video4Linux2 sensor-level driver for the OmniVision
>> +	  OV7251 camera.
>> +
>> +	  To compile this driver as a module, choose M here: the
>> +	  module will be called ov7251.
>> +
>>  config VIDEO_OV772X
>>  	tristate "OmniVision OV772x sensor support"
>>  	depends on I2C && VIDEO_V4L2
>> diff --git a/drivers/media/i2c/Makefile b/drivers/media/i2c/Makefile
>> index ea34aee..c8585b1 100644
>> --- a/drivers/media/i2c/Makefile
>> +++ b/drivers/media/i2c/Makefile
>> @@ -70,6 +70,7 @@ obj-$(CONFIG_VIDEO_OV5647) += ov5647.o
>>  obj-$(CONFIG_VIDEO_OV5670) += ov5670.o
>>  obj-$(CONFIG_VIDEO_OV5695) += ov5695.o
>>  obj-$(CONFIG_VIDEO_OV6650) += ov6650.o
>> +obj-$(CONFIG_VIDEO_OV7251) += ov7251.o
>>  obj-$(CONFIG_VIDEO_OV7640) += ov7640.o
>>  obj-$(CONFIG_VIDEO_OV7670) += ov7670.o
>>  obj-$(CONFIG_VIDEO_OV772X) += ov772x.o
>> diff --git a/drivers/media/i2c/ov7251.c b/drivers/media/i2c/ov7251.c
>> new file mode 100644
>> index 0000000..7b401a9
>> --- /dev/null
>> +++ b/drivers/media/i2c/ov7251.c
>> @@ -0,0 +1,1494 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Driver for the OV7251 camera sensor.
>> + *
>> + * Copyright (c) 2017-2018, The Linux Foundation. All rights reserved.
>> + * Copyright (c) 2017-2018, Linaro Ltd.
>> + */
>> +
>> +#include <linux/bitops.h>
>> +#include <linux/clk.h>
>> +#include <linux/delay.h>
>> +#include <linux/device.h>
>> +#include <linux/gpio/consumer.h>
>> +#include <linux/i2c.h>
>> +#include <linux/init.h>
>> +#include <linux/module.h>
>> +#include <linux/of.h>
>> +#include <linux/of_graph.h>
>> +#include <linux/regulator/consumer.h>
>> +#include <linux/slab.h>
>> +#include <linux/types.h>
>> +#include <media/v4l2-ctrls.h>
>> +#include <media/v4l2-fwnode.h>
>> +#include <media/v4l2-subdev.h>
>> +
>> +#define OV7251_VOLTAGE_ANALOG               2800000
>> +#define OV7251_VOLTAGE_DIGITAL_CORE         1500000
>> +#define OV7251_VOLTAGE_DIGITAL_IO           1800000
>> +
>> +#define OV7251_SC_MODE_SELECT		0x0100
>> +#define OV7251_SC_MODE_SELECT_SW_STANDBY	0x0
>> +#define OV7251_SC_MODE_SELECT_STREAMING		0x1
>> +
>> +#define OV7251_CHIP_ID_HIGH		0x300a
>> +#define OV7251_CHIP_ID_HIGH_BYTE	0x77
>> +#define OV7251_CHIP_ID_LOW		0x300b
>> +#define OV7251_CHIP_ID_LOW_BYTE		0x50
>> +#define OV7251_SC_GP_IO_IN1		0x3029
>> +#define OV7251_AEC_EXPO_0		0x3500
>> +#define OV7251_AEC_EXPO_1		0x3501
>> +#define OV7251_AEC_EXPO_2		0x3502
>> +#define OV7251_AEC_AGC_ADJ_0		0x350a
>> +#define OV7251_AEC_AGC_ADJ_1		0x350b
>> +#define OV7251_TIMING_FORMAT1		0x3820
>> +#define OV7251_TIMING_FORMAT1_VFLIP	BIT(2)
>> +#define OV7251_TIMING_FORMAT2		0x3821
>> +#define OV7251_TIMING_FORMAT2_MIRROR	BIT(2)
>> +#define OV7251_PRE_ISP_00		0x5e00
>> +#define OV7251_PRE_ISP_00_TEST_PATTERN	BIT(7)
>> +
>> +struct reg_value {
>> +	u16 reg;
>> +	u8 val;
>> +};
>> +
>> +struct ov7251_mode_info {
>> +	u32 width;
>> +	u32 height;
>> +	const struct reg_value *data;
>> +	u32 data_size;
>> +	u32 pixel_clock;
>> +	u32 link_freq;
>> +	u16 exposure_max;
>> +	u16 exposure_def;
>> +	struct v4l2_fract timeperframe;
>> +};
>> +
>> +struct ov7251 {
>> +	struct i2c_client *i2c_client;
>> +	struct device *dev;
>> +	struct v4l2_subdev sd;
>> +	struct media_pad pad;
>> +	struct v4l2_fwnode_endpoint ep;
>> +	struct v4l2_mbus_framefmt fmt;
>> +	struct v4l2_rect crop;
>> +	struct clk *xclk;
>> +
>> +	struct regulator *io_regulator;
>> +	struct regulator *core_regulator;
>> +	struct regulator *analog_regulator;
>> +
>> +	const struct ov7251_mode_info *current_mode;
>> +
>> +	struct v4l2_ctrl_handler ctrls;
>> +	struct v4l2_ctrl *pixel_clock;
>> +	struct v4l2_ctrl *link_freq;
>> +	struct v4l2_ctrl *exposure;
>> +	struct v4l2_ctrl *gain;
>> +
>> +	/* Cached register values */
>> +	u8 aec_pk_manual;
>> +	u8 pre_isp_00;
>> +	u8 timing_format1;
>> +	u8 timing_format2;
>> +
>> +	struct mutex power_lock; /* lock to protect power state */
>> +	bool power_on;
>> +
>> +	struct gpio_desc *enable_gpio;
>> +};
>> +
>> +static inline struct ov7251 *to_ov7251(struct v4l2_subdev *sd)
>> +{
>> +	return container_of(sd, struct ov7251, sd);
>> +}
>> +
>> +static const struct reg_value ov7251_global_init_setting[] = {
>> +	{ 0x0103, 0x01 },
>> +	{ 0x303b, 0x02 },
>> +};
>> +
>> +static const struct reg_value ov7251_setting_vga_30fps[] = {
>> +	{ 0x3005, 0x00 },
>> +	{ 0x3012, 0xc0 },
>> +	{ 0x3013, 0xd2 },
>> +	{ 0x3014, 0x04 },
>> +	{ 0x3016, 0xf0 },
>> +	{ 0x3017, 0xf0 },
>> +	{ 0x3018, 0xf0 },
>> +	{ 0x301a, 0xf0 },
>> +	{ 0x301b, 0xf0 },
>> +	{ 0x301c, 0xf0 },
>> +	{ 0x3023, 0x05 },
>> +	{ 0x3037, 0xf0 },
>> +	{ 0x3098, 0x04 }, /* pll2 pre divider */
>> +	{ 0x3099, 0x28 }, /* pll2 multiplier */
>> +	{ 0x309a, 0x05 }, /* pll2 sys divider */
>> +	{ 0x309b, 0x04 }, /* pll2 adc divider */
>> +	{ 0x309d, 0x00 }, /* pll2 divider */
>> +	{ 0x30b0, 0x0a }, /* pll1 pix divider */
>> +	{ 0x30b1, 0x01 }, /* pll1 divider */
>> +	{ 0x30b3, 0x64 }, /* pll1 multiplier */
>> +	{ 0x30b4, 0x03 }, /* pll1 pre divider */
>> +	{ 0x30b5, 0x05 }, /* pll1 mipi divider */
>> +	{ 0x3106, 0xda },
>> +	{ 0x3503, 0x07 },
>> +	{ 0x3509, 0x10 },
>> +	{ 0x3600, 0x1c },
>> +	{ 0x3602, 0x62 },
>> +	{ 0x3620, 0xb7 },
>> +	{ 0x3622, 0x04 },
>> +	{ 0x3626, 0x21 },
>> +	{ 0x3627, 0x30 },
>> +	{ 0x3630, 0x44 },
>> +	{ 0x3631, 0x35 },
>> +	{ 0x3634, 0x60 },
>> +	{ 0x3636, 0x00 },
>> +	{ 0x3662, 0x01 },
>> +	{ 0x3663, 0x70 },
>> +	{ 0x3664, 0x50 },
>> +	{ 0x3666, 0x0a },
>> +	{ 0x3669, 0x1a },
>> +	{ 0x366a, 0x00 },
>> +	{ 0x366b, 0x50 },
>> +	{ 0x3673, 0x01 },
>> +	{ 0x3674, 0xff },
>> +	{ 0x3675, 0x03 },
>> +	{ 0x3705, 0xc1 },
>> +	{ 0x3709, 0x40 },
>> +	{ 0x373c, 0x08 },
>> +	{ 0x3742, 0x00 },
>> +	{ 0x3757, 0xb3 },
>> +	{ 0x3788, 0x00 },
>> +	{ 0x37a8, 0x01 },
>> +	{ 0x37a9, 0xc0 },
>> +	{ 0x3800, 0x00 },
>> +	{ 0x3801, 0x04 },
>> +	{ 0x3802, 0x00 },
>> +	{ 0x3803, 0x04 },
>> +	{ 0x3804, 0x02 },
>> +	{ 0x3805, 0x8b },
>> +	{ 0x3806, 0x01 },
>> +	{ 0x3807, 0xeb },
>> +	{ 0x3808, 0x02 }, /* width high */
>> +	{ 0x3809, 0x80 }, /* width low */
>> +	{ 0x380a, 0x01 }, /* height high */
>> +	{ 0x380b, 0xe0 }, /* height low */
>> +	{ 0x380c, 0x03 }, /* total horiz timing high */
>> +	{ 0x380d, 0xa0 }, /* total horiz timing low */
>> +	{ 0x380e, 0x06 }, /* total vertical timing high */
>> +	{ 0x380f, 0xbc }, /* total vertical timing low */
>> +	{ 0x3810, 0x00 },
>> +	{ 0x3811, 0x04 },
>> +	{ 0x3812, 0x00 },
>> +	{ 0x3813, 0x05 },
>> +	{ 0x3814, 0x11 },
>> +	{ 0x3815, 0x11 },
>> +	{ 0x3820, 0x40 },
>> +	{ 0x3821, 0x00 },
>> +	{ 0x382f, 0x0e },
>> +	{ 0x3832, 0x00 },
>> +	{ 0x3833, 0x05 },
>> +	{ 0x3834, 0x00 },
>> +	{ 0x3835, 0x0c },
>> +	{ 0x3837, 0x00 },
>> +	{ 0x3b80, 0x00 },
>> +	{ 0x3b81, 0xa5 },
>> +	{ 0x3b82, 0x10 },
>> +	{ 0x3b83, 0x00 },
>> +	{ 0x3b84, 0x08 },
>> +	{ 0x3b85, 0x00 },
>> +	{ 0x3b86, 0x01 },
>> +	{ 0x3b87, 0x00 },
>> +	{ 0x3b88, 0x00 },
>> +	{ 0x3b89, 0x00 },
>> +	{ 0x3b8a, 0x00 },
>> +	{ 0x3b8b, 0x05 },
>> +	{ 0x3b8c, 0x00 },
>> +	{ 0x3b8d, 0x00 },
>> +	{ 0x3b8e, 0x00 },
>> +	{ 0x3b8f, 0x1a },
>> +	{ 0x3b94, 0x05 },
>> +	{ 0x3b95, 0xf2 },
>> +	{ 0x3b96, 0x40 },
>> +	{ 0x3c00, 0x89 },
>> +	{ 0x3c01, 0x63 },
>> +	{ 0x3c02, 0x01 },
>> +	{ 0x3c03, 0x00 },
>> +	{ 0x3c04, 0x00 },
>> +	{ 0x3c05, 0x03 },
>> +	{ 0x3c06, 0x00 },
>> +	{ 0x3c07, 0x06 },
>> +	{ 0x3c0c, 0x01 },
>> +	{ 0x3c0d, 0xd0 },
>> +	{ 0x3c0e, 0x02 },
>> +	{ 0x3c0f, 0x0a },
>> +	{ 0x4001, 0x42 },
>> +	{ 0x4004, 0x04 },
>> +	{ 0x4005, 0x00 },
>> +	{ 0x404e, 0x01 },
>> +	{ 0x4300, 0xff },
>> +	{ 0x4301, 0x00 },
>> +	{ 0x4315, 0x00 },
>> +	{ 0x4501, 0x48 },
>> +	{ 0x4600, 0x00 },
>> +	{ 0x4601, 0x4e },
>> +	{ 0x4801, 0x0f },
>> +	{ 0x4806, 0x0f },
>> +	{ 0x4819, 0xaa },
>> +	{ 0x4823, 0x3e },
>> +	{ 0x4837, 0x19 },
>> +	{ 0x4a0d, 0x00 },
>> +	{ 0x4a47, 0x7f },
>> +	{ 0x4a49, 0xf0 },
>> +	{ 0x4a4b, 0x30 },
>> +	{ 0x5000, 0x85 },
>> +	{ 0x5001, 0x80 },
>> +};
>> +
>> +static const struct reg_value ov7251_setting_vga_60fps[] = {
>> +	{ 0x3005, 0x00 },
>> +	{ 0x3012, 0xc0 },
>> +	{ 0x3013, 0xd2 },
>> +	{ 0x3014, 0x04 },
>> +	{ 0x3016, 0x10 },
>> +	{ 0x3017, 0x00 },
>> +	{ 0x3018, 0x00 },
>> +	{ 0x301a, 0x00 },
>> +	{ 0x301b, 0x00 },
>> +	{ 0x301c, 0x00 },
>> +	{ 0x3023, 0x05 },
>> +	{ 0x3037, 0xf0 },
>> +	{ 0x3098, 0x04 }, /* pll2 pre divider */
>> +	{ 0x3099, 0x28 }, /* pll2 multiplier */
>> +	{ 0x309a, 0x05 }, /* pll2 sys divider */
>> +	{ 0x309b, 0x04 }, /* pll2 adc divider */
>> +	{ 0x309d, 0x00 }, /* pll2 divider */
>> +	{ 0x30b0, 0x0a }, /* pll1 pix divider */
>> +	{ 0x30b1, 0x01 }, /* pll1 divider */
>> +	{ 0x30b3, 0x64 }, /* pll1 multiplier */
>> +	{ 0x30b4, 0x03 }, /* pll1 pre divider */
>> +	{ 0x30b5, 0x05 }, /* pll1 mipi divider */
>> +	{ 0x3106, 0xda },
>> +	{ 0x3503, 0x07 },
>> +	{ 0x3509, 0x10 },
>> +	{ 0x3600, 0x1c },
>> +	{ 0x3602, 0x62 },
>> +	{ 0x3620, 0xb7 },
>> +	{ 0x3622, 0x04 },
>> +	{ 0x3626, 0x21 },
>> +	{ 0x3627, 0x30 },
>> +	{ 0x3630, 0x44 },
>> +	{ 0x3631, 0x35 },
>> +	{ 0x3634, 0x60 },
>> +	{ 0x3636, 0x00 },
>> +	{ 0x3662, 0x01 },
>> +	{ 0x3663, 0x70 },
>> +	{ 0x3664, 0x50 },
>> +	{ 0x3666, 0x0a },
>> +	{ 0x3669, 0x1a },
>> +	{ 0x366a, 0x00 },
>> +	{ 0x366b, 0x50 },
>> +	{ 0x3673, 0x01 },
>> +	{ 0x3674, 0xff },
>> +	{ 0x3675, 0x03 },
>> +	{ 0x3705, 0xc1 },
>> +	{ 0x3709, 0x40 },
>> +	{ 0x373c, 0x08 },
>> +	{ 0x3742, 0x00 },
>> +	{ 0x3757, 0xb3 },
>> +	{ 0x3788, 0x00 },
>> +	{ 0x37a8, 0x01 },
>> +	{ 0x37a9, 0xc0 },
>> +	{ 0x3800, 0x00 },
>> +	{ 0x3801, 0x04 },
>> +	{ 0x3802, 0x00 },
>> +	{ 0x3803, 0x04 },
>> +	{ 0x3804, 0x02 },
>> +	{ 0x3805, 0x8b },
>> +	{ 0x3806, 0x01 },
>> +	{ 0x3807, 0xeb },
>> +	{ 0x3808, 0x02 }, /* width high */
>> +	{ 0x3809, 0x80 }, /* width low */
>> +	{ 0x380a, 0x01 }, /* height high */
>> +	{ 0x380b, 0xe0 }, /* height low */
>> +	{ 0x380c, 0x03 }, /* total horiz timing high */
>> +	{ 0x380d, 0xa0 }, /* total horiz timing low */
>> +	{ 0x380e, 0x03 }, /* total vertical timing high */
>> +	{ 0x380f, 0x5c }, /* total vertical timing low */
>> +	{ 0x3810, 0x00 },
>> +	{ 0x3811, 0x04 },
>> +	{ 0x3812, 0x00 },
>> +	{ 0x3813, 0x05 },
>> +	{ 0x3814, 0x11 },
>> +	{ 0x3815, 0x11 },
>> +	{ 0x3820, 0x40 },
>> +	{ 0x3821, 0x00 },
>> +	{ 0x382f, 0x0e },
>> +	{ 0x3832, 0x00 },
>> +	{ 0x3833, 0x05 },
>> +	{ 0x3834, 0x00 },
>> +	{ 0x3835, 0x0c },
>> +	{ 0x3837, 0x00 },
>> +	{ 0x3b80, 0x00 },
>> +	{ 0x3b81, 0xa5 },
>> +	{ 0x3b82, 0x10 },
>> +	{ 0x3b83, 0x00 },
>> +	{ 0x3b84, 0x08 },
>> +	{ 0x3b85, 0x00 },
>> +	{ 0x3b86, 0x01 },
>> +	{ 0x3b87, 0x00 },
>> +	{ 0x3b88, 0x00 },
>> +	{ 0x3b89, 0x00 },
>> +	{ 0x3b8a, 0x00 },
>> +	{ 0x3b8b, 0x05 },
>> +	{ 0x3b8c, 0x00 },
>> +	{ 0x3b8d, 0x00 },
>> +	{ 0x3b8e, 0x00 },
>> +	{ 0x3b8f, 0x1a },
>> +	{ 0x3b94, 0x05 },
>> +	{ 0x3b95, 0xf2 },
>> +	{ 0x3b96, 0x40 },
>> +	{ 0x3c00, 0x89 },
>> +	{ 0x3c01, 0x63 },
>> +	{ 0x3c02, 0x01 },
>> +	{ 0x3c03, 0x00 },
>> +	{ 0x3c04, 0x00 },
>> +	{ 0x3c05, 0x03 },
>> +	{ 0x3c06, 0x00 },
>> +	{ 0x3c07, 0x06 },
>> +	{ 0x3c0c, 0x01 },
>> +	{ 0x3c0d, 0xd0 },
>> +	{ 0x3c0e, 0x02 },
>> +	{ 0x3c0f, 0x0a },
>> +	{ 0x4001, 0x42 },
>> +	{ 0x4004, 0x04 },
>> +	{ 0x4005, 0x00 },
>> +	{ 0x404e, 0x01 },
>> +	{ 0x4300, 0xff },
>> +	{ 0x4301, 0x00 },
>> +	{ 0x4315, 0x00 },
>> +	{ 0x4501, 0x48 },
>> +	{ 0x4600, 0x00 },
>> +	{ 0x4601, 0x4e },
>> +	{ 0x4801, 0x0f },
>> +	{ 0x4806, 0x0f },
>> +	{ 0x4819, 0xaa },
>> +	{ 0x4823, 0x3e },
>> +	{ 0x4837, 0x19 },
>> +	{ 0x4a0d, 0x00 },
>> +	{ 0x4a47, 0x7f },
>> +	{ 0x4a49, 0xf0 },
>> +	{ 0x4a4b, 0x30 },
>> +	{ 0x5000, 0x85 },
>> +	{ 0x5001, 0x80 },
>> +};
>> +
>> +static const struct reg_value ov7251_setting_vga_90fps[] = {
>> +	{ 0x3005, 0x00 },
>> +	{ 0x3012, 0xc0 },
>> +	{ 0x3013, 0xd2 },
>> +	{ 0x3014, 0x04 },
>> +	{ 0x3016, 0x10 },
>> +	{ 0x3017, 0x00 },
>> +	{ 0x3018, 0x00 },
>> +	{ 0x301a, 0x00 },
>> +	{ 0x301b, 0x00 },
>> +	{ 0x301c, 0x00 },
>> +	{ 0x3023, 0x05 },
>> +	{ 0x3037, 0xf0 },
>> +	{ 0x3098, 0x04 }, /* pll2 pre divider */
>> +	{ 0x3099, 0x28 }, /* pll2 multiplier */
>> +	{ 0x309a, 0x05 }, /* pll2 sys divider */
>> +	{ 0x309b, 0x04 }, /* pll2 adc divider */
>> +	{ 0x309d, 0x00 }, /* pll2 divider */
>> +	{ 0x30b0, 0x0a }, /* pll1 pix divider */
>> +	{ 0x30b1, 0x01 }, /* pll1 divider */
>> +	{ 0x30b3, 0x64 }, /* pll1 multiplier */
>> +	{ 0x30b4, 0x03 }, /* pll1 pre divider */
>> +	{ 0x30b5, 0x05 }, /* pll1 mipi divider */
>> +	{ 0x3106, 0xda },
>> +	{ 0x3503, 0x07 },
>> +	{ 0x3509, 0x10 },
>> +	{ 0x3600, 0x1c },
>> +	{ 0x3602, 0x62 },
>> +	{ 0x3620, 0xb7 },
>> +	{ 0x3622, 0x04 },
>> +	{ 0x3626, 0x21 },
>> +	{ 0x3627, 0x30 },
>> +	{ 0x3630, 0x44 },
>> +	{ 0x3631, 0x35 },
>> +	{ 0x3634, 0x60 },
>> +	{ 0x3636, 0x00 },
>> +	{ 0x3662, 0x01 },
>> +	{ 0x3663, 0x70 },
>> +	{ 0x3664, 0x50 },
>> +	{ 0x3666, 0x0a },
>> +	{ 0x3669, 0x1a },
>> +	{ 0x366a, 0x00 },
>> +	{ 0x366b, 0x50 },
>> +	{ 0x3673, 0x01 },
>> +	{ 0x3674, 0xff },
>> +	{ 0x3675, 0x03 },
>> +	{ 0x3705, 0xc1 },
>> +	{ 0x3709, 0x40 },
>> +	{ 0x373c, 0x08 },
>> +	{ 0x3742, 0x00 },
>> +	{ 0x3757, 0xb3 },
>> +	{ 0x3788, 0x00 },
>> +	{ 0x37a8, 0x01 },
>> +	{ 0x37a9, 0xc0 },
>> +	{ 0x3800, 0x00 },
>> +	{ 0x3801, 0x04 },
>> +	{ 0x3802, 0x00 },
>> +	{ 0x3803, 0x04 },
>> +	{ 0x3804, 0x02 },
>> +	{ 0x3805, 0x8b },
>> +	{ 0x3806, 0x01 },
>> +	{ 0x3807, 0xeb },
>> +	{ 0x3808, 0x02 }, /* width high */
>> +	{ 0x3809, 0x80 }, /* width low */
>> +	{ 0x380a, 0x01 }, /* height high */
>> +	{ 0x380b, 0xe0 }, /* height low */
>> +	{ 0x380c, 0x03 }, /* total horiz timing high */
>> +	{ 0x380d, 0xa0 }, /* total horiz timing low */
>> +	{ 0x380e, 0x02 }, /* total vertical timing high */
>> +	{ 0x380f, 0x3c }, /* total vertical timing low */
>> +	{ 0x3810, 0x00 },
>> +	{ 0x3811, 0x04 },
>> +	{ 0x3812, 0x00 },
>> +	{ 0x3813, 0x05 },
>> +	{ 0x3814, 0x11 },
>> +	{ 0x3815, 0x11 },
>> +	{ 0x3820, 0x40 },
>> +	{ 0x3821, 0x00 },
>> +	{ 0x382f, 0x0e },
>> +	{ 0x3832, 0x00 },
>> +	{ 0x3833, 0x05 },
>> +	{ 0x3834, 0x00 },
>> +	{ 0x3835, 0x0c },
>> +	{ 0x3837, 0x00 },
>> +	{ 0x3b80, 0x00 },
>> +	{ 0x3b81, 0xa5 },
>> +	{ 0x3b82, 0x10 },
>> +	{ 0x3b83, 0x00 },
>> +	{ 0x3b84, 0x08 },
>> +	{ 0x3b85, 0x00 },
>> +	{ 0x3b86, 0x01 },
>> +	{ 0x3b87, 0x00 },
>> +	{ 0x3b88, 0x00 },
>> +	{ 0x3b89, 0x00 },
>> +	{ 0x3b8a, 0x00 },
>> +	{ 0x3b8b, 0x05 },
>> +	{ 0x3b8c, 0x00 },
>> +	{ 0x3b8d, 0x00 },
>> +	{ 0x3b8e, 0x00 },
>> +	{ 0x3b8f, 0x1a },
>> +	{ 0x3b94, 0x05 },
>> +	{ 0x3b95, 0xf2 },
>> +	{ 0x3b96, 0x40 },
>> +	{ 0x3c00, 0x89 },
>> +	{ 0x3c01, 0x63 },
>> +	{ 0x3c02, 0x01 },
>> +	{ 0x3c03, 0x00 },
>> +	{ 0x3c04, 0x00 },
>> +	{ 0x3c05, 0x03 },
>> +	{ 0x3c06, 0x00 },
>> +	{ 0x3c07, 0x06 },
>> +	{ 0x3c0c, 0x01 },
>> +	{ 0x3c0d, 0xd0 },
>> +	{ 0x3c0e, 0x02 },
>> +	{ 0x3c0f, 0x0a },
>> +	{ 0x4001, 0x42 },
>> +	{ 0x4004, 0x04 },
>> +	{ 0x4005, 0x00 },
>> +	{ 0x404e, 0x01 },
>> +	{ 0x4300, 0xff },
>> +	{ 0x4301, 0x00 },
>> +	{ 0x4315, 0x00 },
>> +	{ 0x4501, 0x48 },
>> +	{ 0x4600, 0x00 },
>> +	{ 0x4601, 0x4e },
>> +	{ 0x4801, 0x0f },
>> +	{ 0x4806, 0x0f },
>> +	{ 0x4819, 0xaa },
>> +	{ 0x4823, 0x3e },
>> +	{ 0x4837, 0x19 },
>> +	{ 0x4a0d, 0x00 },
>> +	{ 0x4a47, 0x7f },
>> +	{ 0x4a49, 0xf0 },
>> +	{ 0x4a4b, 0x30 },
>> +	{ 0x5000, 0x85 },
>> +	{ 0x5001, 0x80 },
>> +};
>> +
>> +static const s64 link_freq[] = {
>> +	240000000,
>> +};
>> +
>> +static const struct ov7251_mode_info ov7251_mode_info_data[] = {
>> +	{
>> +		.width = 640,
>> +		.height = 480,
>> +		.data = ov7251_setting_vga_30fps,
>> +		.data_size = ARRAY_SIZE(ov7251_setting_vga_30fps),
>> +		.pixel_clock = 48000000,
>> +		.link_freq = 0, /* an index in link_freq[] */
>> +		.exposure_max = 1704,
>> +		.exposure_def = 504,
>> +		.timeperframe = {
>> +			.numerator = 100,
>> +			.denominator = 3000
>> +		}
>> +	},
>> +	{
>> +		.width = 640,
>> +		.height = 480,
>> +		.data = ov7251_setting_vga_60fps,
>> +		.data_size = ARRAY_SIZE(ov7251_setting_vga_60fps),
>> +		.pixel_clock = 48000000,
>> +		.link_freq = 0, /* an index in link_freq[] */
>> +		.exposure_max = 840,
>> +		.exposure_def = 504,
>> +		.timeperframe = {
>> +			.numerator = 100,
>> +			.denominator = 6014
>> +		}
>> +	},
>> +	{
>> +		.width = 640,
>> +		.height = 480,
>> +		.data = ov7251_setting_vga_90fps,
>> +		.data_size = ARRAY_SIZE(ov7251_setting_vga_90fps),
>> +		.pixel_clock = 48000000,
>> +		.link_freq = 0, /* an index in link_freq[] */
>> +		.exposure_max = 552,
>> +		.exposure_def = 504,
>> +		.timeperframe = {
>> +			.numerator = 100,
>> +			.denominator = 9043
>> +		}
>> +	},
>> +};
>> +
>> +static int ov7251_regulators_enable(struct ov7251 *ov7251)
>> +{
>> +	int ret;
>> +
>> +	ret = regulator_enable(ov7251->io_regulator);
> 
> How about regulator_bulk_enable() here, and bulk_disable below?

I'm not using the bulk API because usually there is a power up
sequence and intervals that must be followed. For this sensor
the only constraint is that core regulator must be enabled
after io regulator. But the bulk API doesn't guarantee the
order.

> 
>> +	if (ret < 0) {
>> +		dev_err(ov7251->dev, "set io voltage failed\n");
>> +		return ret;
>> +	}
>> +
>> +	ret = regulator_enable(ov7251->analog_regulator);
>> +	if (ret) {
>> +		dev_err(ov7251->dev, "set analog voltage failed\n");
>> +		goto err_disable_io;
>> +	}
>> +
>> +	ret = regulator_enable(ov7251->core_regulator);
>> +	if (ret) {
>> +		dev_err(ov7251->dev, "set core voltage failed\n");
>> +		goto err_disable_analog;
>> +	}
>> +
>> +	return 0;
>> +
>> +err_disable_analog:
>> +	regulator_disable(ov7251->analog_regulator);
>> +err_disable_io:
>> +	regulator_disable(ov7251->io_regulator);
>> +
>> +	return ret;
>> +}
>> +
>> +static void ov7251_regulators_disable(struct ov7251 *ov7251)
>> +{
>> +	int ret;
>> +
>> +	ret = regulator_disable(ov7251->core_regulator);
>> +	if (ret < 0)
>> +		dev_err(ov7251->dev, "core regulator disable failed\n");
>> +
>> +	ret = regulator_disable(ov7251->analog_regulator);
>> +	if (ret < 0)
>> +		dev_err(ov7251->dev, "analog regulator disable failed\n");
>> +
>> +	ret = regulator_disable(ov7251->io_regulator);
>> +	if (ret < 0)
>> +		dev_err(ov7251->dev, "io regulator disable failed\n");
>> +}
>> +
>> +static int ov7251_write_reg(struct ov7251 *ov7251, u16 reg, u8 val)
>> +{
>> +	u8 regbuf[3];
>> +	int ret;
>> +
>> +	regbuf[0] = reg >> 8;
>> +	regbuf[1] = reg & 0xff;
>> +	regbuf[2] = val;
>> +
>> +	ret = i2c_master_send(ov7251->i2c_client, regbuf, 3);
>> +	if (ret < 0) {
>> +		dev_err(ov7251->dev, "%s: write reg error %d: reg=%x, val=%x\n",
>> +			__func__, ret, reg, val);
>> +		return ret;
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +static int ov7251_read_reg(struct ov7251 *ov7251, u16 reg, u8 *val)
>> +{
>> +	u8 regbuf[2];
>> +	int ret;
>> +
>> +	regbuf[0] = reg >> 8;
>> +	regbuf[1] = reg & 0xff;
>> +
>> +	ret = i2c_master_send(ov7251->i2c_client, regbuf, 2);
>> +	if (ret < 0) {
>> +		dev_err(ov7251->dev, "%s: write reg error %d: reg=%x\n",
>> +			__func__, ret, reg);
>> +		return ret;
>> +	}
>> +
>> +	ret = i2c_master_recv(ov7251->i2c_client, val, 1);
>> +	if (ret < 0) {
>> +		dev_err(ov7251->dev, "%s: read reg error %d: reg=%x\n",
>> +			__func__, ret, reg);
>> +		return ret;
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +static int ov7251_set_exposure(struct ov7251 *ov7251, s32 exposure)
>> +{
>> +	int ret;
>> +
>> +	ret = ov7251_write_reg(ov7251, OV7251_AEC_EXPO_0,
>> +			       (exposure & 0xf000) >> 12);
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	ret = ov7251_write_reg(ov7251, OV7251_AEC_EXPO_1,
>> +			       (exposure & 0x0ff0) >> 4);
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	return ov7251_write_reg(ov7251, OV7251_AEC_EXPO_2,
>> +				(exposure & 0x000f) << 4);
> 
> It's not a good idea to access multi-octet registers separately. Depending
> on the hardware implementation, the hardware could latch the value in the
> middle of an update. This is only an issue during streaming in practice
> though.

Good point. The sensor has a group write functionality which can be used
to solve this but in general is intended
to apply a group of exposure and gain settings in the same frame. However
it seems to me that is not possible to use this functionality efficiently
with the currently available user controls. The group write is configured
using an id for a group of commands. So if we configure exposure and gain
separately (a group for each):
- if the driver uses same group id for exposure and gain, if both controls
  are received in one frame the second will overwrite the first (the
  first will not be applied);
- if the driver uses different group id for exposure and gain, it will not
  be possible for the user to change exposure and gain in the same frame
  (as some exposure algorithms do) and it will lead again to frames with
  "incorrect" brightness.

To do this correctly we will have to extend the API to be able to apply
exposure and gain "atomically":
- a single user control which will set both exposure and gain and it will
  guarantee that they will be applied in the same frame;
- some kind of: begin, set exposure, set gain, end, launch -API

What do you think?

Actually, I'm a little bit surprised that I didn't find anything
like this already. And there are already a number of sensor drivers
which update more than one register to set exposure.

> 
>> +}
>> +
>> +static int ov7251_set_gain(struct ov7251 *ov7251, s32 gain)
>> +{
>> +	int ret;
>> +
>> +	ret = ov7251_write_reg(ov7251, OV7251_AEC_AGC_ADJ_0,
>> +			       (gain & 0x0300) >> 8);
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	return ov7251_write_reg(ov7251, OV7251_AEC_AGC_ADJ_1, gain & 0xff);
>> +}
>> +
>> +static int ov7251_set_register_array(struct ov7251 *ov7251,
>> +				     const struct reg_value *settings,
>> +				     unsigned int num_settings)
>> +{
>> +	unsigned int i;
>> +	int ret;
>> +
>> +	for (i = 0; i < num_settings; ++i, ++settings) {
>> +		ret = ov7251_write_reg(ov7251, settings->reg, settings->val);
>> +		if (ret < 0)
>> +			return ret;
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +static int ov7251_set_power_on(struct ov7251 *ov7251)
>> +{
>> +	int ret;
>> +
>> +	ret = ov7251_regulators_enable(ov7251);
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	ret = clk_prepare_enable(ov7251->xclk);
>> +	if (ret < 0) {
>> +		dev_err(ov7251->dev, "clk prepare enable failed\n");
>> +		ov7251_regulators_disable(ov7251);
>> +		return ret;
>> +	}
>> +
>> +	gpiod_set_value_cansleep(ov7251->enable_gpio, 1);
>> +
>> +	usleep_range(3000, 4000); /* 65536 / 24MHz = 2.73ms */
> 
> What's the minimum time required between lifting XSHUTDOWN and I²C access?
> Could you calculate the value based on the external clock frequency
> instead?

The minimum time is 65536 external clock cycles. So, yes, it will be nicer
to calculate it :)

> 
>> +
>> +	return 0;
>> +}
>> +
>> +static void ov7251_set_power_off(struct ov7251 *ov7251)
>> +{
>> +	clk_disable_unprepare(ov7251->xclk);
>> +	gpiod_set_value_cansleep(ov7251->enable_gpio, 0);
>> +	ov7251_regulators_disable(ov7251);
>> +}
>> +
>> +static int ov7251_s_power(struct v4l2_subdev *sd, int on)
>> +{
>> +	struct ov7251 *ov7251 = to_ov7251(sd);
>> +	int ret = 0;
>> +
>> +	mutex_lock(&ov7251->power_lock);
>> +
>> +	/*
>> +	 * If the power state is modified from 0 to 1 or from 1 to 0,
>> +	 * update the power state.
>> +	 */
>> +	if (ov7251->power_on == !on) {
>> +		if (on) {
>> +			ret = ov7251_set_power_on(ov7251);
>> +			if (ret < 0)
>> +				goto exit;
>> +
>> +			ret = ov7251_set_register_array(ov7251,
>> +					ov7251_global_init_setting,
>> +					ARRAY_SIZE(ov7251_global_init_setting));
>> +			if (ret < 0) {
>> +				dev_err(ov7251->dev,
>> +					"could not set init registers\n");
>> +				ov7251_set_power_off(ov7251);
>> +				goto exit;
>> +			}
>> +
>> +			ov7251->power_on = true;
>> +		} else {
>> +			ov7251_set_power_off(ov7251);
>> +			ov7251->power_on = false;
>> +		}
>> +	}
>> +
>> +exit:
>> +	mutex_unlock(&ov7251->power_lock);
>> +
>> +	return ret;
>> +}
>> +
>> +static int ov7251_set_hflip(struct ov7251 *ov7251, s32 value)
>> +{
>> +	u8 val = ov7251->timing_format2;
>> +	int ret;
>> +
>> +	if (value)
>> +		val |= OV7251_TIMING_FORMAT2_MIRROR;
>> +	else
>> +		val &= ~OV7251_TIMING_FORMAT2_MIRROR;
>> +
>> +	ret = ov7251_write_reg(ov7251, OV7251_TIMING_FORMAT2, val);
>> +	if (!ret)
>> +		ov7251->timing_format2 = val;
>> +
>> +	return ret;
>> +}
>> +
>> +static int ov7251_set_vflip(struct ov7251 *ov7251, s32 value)
>> +{
>> +	u8 val = ov7251->timing_format1;
>> +	int ret;
>> +
>> +	if (value)
>> +		val |= OV7251_TIMING_FORMAT1_VFLIP;
>> +	else
>> +		val &= ~OV7251_TIMING_FORMAT1_VFLIP;
>> +
>> +	ret = ov7251_write_reg(ov7251, OV7251_TIMING_FORMAT1, val);
>> +	if (!ret)
>> +		ov7251->timing_format1 = val;
>> +
>> +	return ret;
>> +}
>> +
>> +static int ov7251_set_test_pattern(struct ov7251 *ov7251, s32 value)
>> +{
>> +	u8 val = ov7251->pre_isp_00;
>> +	int ret;
>> +
>> +	if (value)
>> +		val |= OV7251_PRE_ISP_00_TEST_PATTERN;
>> +	else
>> +		val &= ~OV7251_PRE_ISP_00_TEST_PATTERN;
>> +
>> +	ret = ov7251_write_reg(ov7251, OV7251_PRE_ISP_00, val);
>> +	if (!ret)
>> +		ov7251->pre_isp_00 = val;
>> +
>> +	return ret;
>> +}
>> +
>> +static const char * const ov7251_test_pattern_menu[] = {
>> +	"Disabled",
>> +	"Vertical Pattern Bars",
>> +};
>> +
>> +static int ov7251_s_ctrl(struct v4l2_ctrl *ctrl)
>> +{
>> +	struct ov7251 *ov7251 = container_of(ctrl->handler,
>> +					     struct ov7251, ctrls);
>> +	int ret;
>> +
>> +	mutex_lock(&ov7251->power_lock);
>> +	if (!ov7251->power_on) {
>> +		mutex_unlock(&ov7251->power_lock);
>> +		return 0;
>> +	}
>> +
>> +	switch (ctrl->id) {
>> +	case V4L2_CID_EXPOSURE:
>> +		ret = ov7251_set_exposure(ov7251, ctrl->val);
>> +		break;
>> +	case V4L2_CID_GAIN:
>> +		ret = ov7251_set_gain(ov7251, ctrl->val);
>> +		break;
>> +	case V4L2_CID_TEST_PATTERN:
>> +		ret = ov7251_set_test_pattern(ov7251, ctrl->val);
>> +		break;
>> +	case V4L2_CID_HFLIP:
>> +		ret = ov7251_set_hflip(ov7251, ctrl->val);
>> +		break;
>> +	case V4L2_CID_VFLIP:
>> +		ret = ov7251_set_vflip(ov7251, ctrl->val);
>> +		break;
>> +	default:
>> +		ret = -EINVAL;
>> +		break;
>> +	}
>> +
>> +	mutex_unlock(&ov7251->power_lock);
>> +
>> +	return ret;
>> +}
>> +
>> +static const struct v4l2_ctrl_ops ov7251_ctrl_ops = {
>> +	.s_ctrl = ov7251_s_ctrl,
>> +};
>> +
>> +static int ov7251_enum_mbus_code(struct v4l2_subdev *sd,
>> +				 struct v4l2_subdev_pad_config *cfg,
>> +				 struct v4l2_subdev_mbus_code_enum *code)
>> +{
>> +	if (code->index > 0)
>> +		return -EINVAL;
>> +
>> +	code->code = MEDIA_BUS_FMT_SBGGR10_1X10;
>> +
>> +	return 0;
>> +}
>> +
>> +static int ov7251_enum_frame_size(struct v4l2_subdev *subdev,
>> +				  struct v4l2_subdev_pad_config *cfg,
>> +				  struct v4l2_subdev_frame_size_enum *fse)
>> +{
>> +	if (fse->code != MEDIA_BUS_FMT_SBGGR10_1X10)
> 
> Can the flip controls affect the media bus code? Either take this into
> account or remove flip controls.

This sensor is black and white (monochrome). I have used BGGR because I
didn't find any monochrome format amongst the Bayer formats. Looking
again at it now, probably we have to use MEDIA_BUS_FMT_Y10_1X10?

However I cannot find a suitable pixel format too (to be used by the
platform driver) as the output is MIPI10 (same encoding as
V4L2_PIX_FMT_SBGGR10P but monochrome) and V4L2_PIX_FMT_Y10BPACK has
different encoding. So it seems to me that I will have to add another
pixel format, right?

> 
>> +		return -EINVAL;
>> +
>> +	if (fse->index >= ARRAY_SIZE(ov7251_mode_info_data))
>> +		return -EINVAL;
>> +
>> +	fse->min_width = ov7251_mode_info_data[fse->index].width;
>> +	fse->max_width = ov7251_mode_info_data[fse->index].width;
>> +	fse->min_height = ov7251_mode_info_data[fse->index].height;
>> +	fse->max_height = ov7251_mode_info_data[fse->index].height;
>> +
>> +	return 0;
>> +}
>> +
>> +static int ov7251_enum_frame_ival(struct v4l2_subdev *subdev,
>> +				  struct v4l2_subdev_pad_config *cfg,
>> +				  struct v4l2_subdev_frame_interval_enum *fie)
>> +{
>> +	int index = fie->index;
>> +	int i;
>> +
>> +	for (i = 0; i < ARRAY_SIZE(ov7251_mode_info_data); i++) {
>> +		if (fie->width != ov7251_mode_info_data[i].width ||
>> +		    fie->height != ov7251_mode_info_data[i].height)
>> +			continue;
>> +
>> +		if (index-- == 0) {
>> +			fie->interval = ov7251_mode_info_data[i].timeperframe;
>> +			return 0;
>> +		}
>> +	}
>> +
>> +	return -EINVAL;
>> +}
>> +
>> +static struct v4l2_mbus_framefmt *
>> +__ov7251_get_pad_format(struct ov7251 *ov7251,
>> +			struct v4l2_subdev_pad_config *cfg,
>> +			unsigned int pad,
>> +			enum v4l2_subdev_format_whence which)
>> +{
>> +	switch (which) {
>> +	case V4L2_SUBDEV_FORMAT_TRY:
>> +		return v4l2_subdev_get_try_format(&ov7251->sd, cfg, pad);
>> +	case V4L2_SUBDEV_FORMAT_ACTIVE:
>> +		return &ov7251->fmt;
>> +	default:
>> +		return NULL;
>> +	}
>> +}
>> +
>> +static int ov7251_get_format(struct v4l2_subdev *sd,
>> +			     struct v4l2_subdev_pad_config *cfg,
>> +			     struct v4l2_subdev_format *format)
>> +{
>> +	struct ov7251 *ov7251 = to_ov7251(sd);
>> +
>> +	format->format = *__ov7251_get_pad_format(ov7251, cfg, format->pad,
>> +						  format->which);
>> +	return 0;
>> +}
>> +
>> +static struct v4l2_rect *
>> +__ov7251_get_pad_crop(struct ov7251 *ov7251, struct v4l2_subdev_pad_config *cfg,
>> +		      unsigned int pad, enum v4l2_subdev_format_whence which)
>> +{
>> +	switch (which) {
>> +	case V4L2_SUBDEV_FORMAT_TRY:
>> +		return v4l2_subdev_get_try_crop(&ov7251->sd, cfg, pad);
>> +	case V4L2_SUBDEV_FORMAT_ACTIVE:
>> +		return &ov7251->crop;
>> +	default:
>> +		return NULL;
>> +	}
>> +}
>> +
>> +#define TIMEPERFRAME_AVG_FPS(t)						\
>> +	(((t).denominator + ((t).numerator >> 1)) / (t).numerator)
>> +
>> +static const struct ov7251_mode_info *
>> +ov7251_find_mode_by_ival(struct ov7251 *ov7251, struct v4l2_fract *timeperframe)
>> +{
>> +	const struct ov7251_mode_info *mode = ov7251->current_mode;
>> +	int fps_req = TIMEPERFRAME_AVG_FPS(*timeperframe);
>> +	unsigned int max_dist_match = (unsigned int) -1;
>> +	int i, n = 0;
>> +
>> +	for (i = 0; i < ARRAY_SIZE(ov7251_mode_info_data); i++) {
>> +		unsigned int dist;
>> +		int fps_tmp;
>> +
>> +		if (mode->width != ov7251_mode_info_data[i].width ||
>> +		    mode->height != ov7251_mode_info_data[i].height)
>> +			continue;
>> +
>> +		fps_tmp = TIMEPERFRAME_AVG_FPS(
>> +					ov7251_mode_info_data[i].timeperframe);
>> +
>> +		dist = abs(fps_req - fps_tmp);
>> +
>> +		if (dist < max_dist_match) {
>> +			n = i;
>> +			max_dist_match = dist;
>> +		}
>> +	}
>> +
>> +	return &ov7251_mode_info_data[n];
>> +}
>> +
>> +static int ov7251_set_format(struct v4l2_subdev *sd,
>> +			     struct v4l2_subdev_pad_config *cfg,
>> +			     struct v4l2_subdev_format *format)
>> +{
>> +	struct ov7251 *ov7251 = to_ov7251(sd);
>> +	struct v4l2_mbus_framefmt *__format;
>> +	struct v4l2_rect *__crop;
>> +	const struct ov7251_mode_info *new_mode;
>> +	int ret;
>> +
> 
> Does setting the mode need to be serialised? Right now it doesn't seem to
> be. There seem to be dependencies between the controls as well as the
> format...
> 
> Same for s_stream, to avoid the format to be changed while starting
> streaming.

Yes, I'll add locking.

> 
>> +	__crop = __ov7251_get_pad_crop(ov7251, cfg, format->pad,
>> +			format->which);
>> +
>> +	new_mode = v4l2_find_nearest_size(ov7251_mode_info_data,
>> +			       width, height,
>> +			       format->format.width, format->format.height);
>> +
>> +	__crop->width = new_mode->width;
>> +	__crop->height = new_mode->height;
>> +
>> +	if (format->which == V4L2_SUBDEV_FORMAT_ACTIVE) {
>> +		ret = v4l2_ctrl_s_ctrl_int64(ov7251->pixel_clock,
>> +					     new_mode->pixel_clock);
>> +		if (ret < 0)
>> +			return ret;
>> +
>> +		ret = v4l2_ctrl_s_ctrl(ov7251->link_freq,
>> +				       new_mode->link_freq);
>> +		if (ret < 0)
>> +			return ret;
>> +
>> +		ret = v4l2_ctrl_modify_range(ov7251->exposure,
>> +					     1, new_mode->exposure_max,
>> +					     1, new_mode->exposure_def);
>> +		if (ret < 0)
>> +			return ret;
>> +
>> +		ret = v4l2_ctrl_s_ctrl(ov7251->exposure,
>> +				       new_mode->exposure_def);
>> +		if (ret < 0)
>> +			return ret;
>> +
>> +
>> +		ret = v4l2_ctrl_s_ctrl(ov7251->gain, 16);
>> +		if (ret < 0)
>> +			return ret;
>> +
>> +		ov7251->current_mode = new_mode;
>> +	}
>> +
>> +	__format = __ov7251_get_pad_format(ov7251, cfg, format->pad,
>> +			format->which);
>> +	__format->width = __crop->width;
>> +	__format->height = __crop->height;
>> +	__format->code = MEDIA_BUS_FMT_SBGGR10_1X10;
>> +	__format->field = V4L2_FIELD_NONE;
>> +	__format->colorspace = V4L2_COLORSPACE_SRGB;
>> +	__format->ycbcr_enc = V4L2_MAP_YCBCR_ENC_DEFAULT(__format->colorspace);
>> +	__format->quantization = V4L2_MAP_QUANTIZATION_DEFAULT(true,
>> +				__format->colorspace, __format->ycbcr_enc);
>> +	__format->xfer_func = V4L2_MAP_XFER_FUNC_DEFAULT(__format->colorspace);
>> +
>> +	format->format = *__format;
>> +
>> +	return 0;
>> +}
>> +
>> +static int ov7251_entity_init_cfg(struct v4l2_subdev *subdev,
>> +				  struct v4l2_subdev_pad_config *cfg)
>> +{
>> +	struct v4l2_subdev_format fmt = { 0 };
>> +
>> +	fmt.which = cfg ? V4L2_SUBDEV_FORMAT_TRY : V4L2_SUBDEV_FORMAT_ACTIVE;
>> +	fmt.format.width = 640;
>> +	fmt.format.height = 480;
>> +
>> +	ov7251_set_format(subdev, cfg, &fmt);
>> +
>> +	return 0;
>> +}
>> +
>> +static int ov7251_get_selection(struct v4l2_subdev *sd,
>> +			   struct v4l2_subdev_pad_config *cfg,
>> +			   struct v4l2_subdev_selection *sel)
>> +{
>> +	struct ov7251 *ov7251 = to_ov7251(sd);
>> +
>> +	if (sel->target != V4L2_SEL_TGT_CROP)
>> +		return -EINVAL;
>> +
>> +	sel->r = *__ov7251_get_pad_crop(ov7251, cfg, sel->pad,
>> +					sel->which);
>> +	return 0;
>> +}
>> +
>> +static int ov7251_s_stream(struct v4l2_subdev *subdev, int enable)
>> +{
>> +	struct ov7251 *ov7251 = to_ov7251(subdev);
>> +	int ret;
>> +
>> +	if (enable) {
>> +		ret = ov7251_set_register_array(ov7251,
>> +					ov7251->current_mode->data,
>> +					ov7251->current_mode->data_size);
>> +		if (ret < 0) {
>> +			dev_err(ov7251->dev, "could not set mode %dx%d\n",
>> +				ov7251->current_mode->width,
>> +				ov7251->current_mode->height);
>> +			return ret;
>> +		}
>> +		ret = v4l2_ctrl_handler_setup(&ov7251->ctrls);
>> +		if (ret < 0) {
>> +			dev_err(ov7251->dev, "could not sync v4l2 controls\n");
>> +			return ret;
>> +		}
>> +		ret = ov7251_write_reg(ov7251, OV7251_SC_MODE_SELECT,
>> +				       OV7251_SC_MODE_SELECT_STREAMING);
>> +		if (ret < 0)
>> +			return ret;
>> +	} else {
>> +		ret = ov7251_write_reg(ov7251, OV7251_SC_MODE_SELECT,
>> +				       OV7251_SC_MODE_SELECT_SW_STANDBY);
>> +		if (ret < 0)
>> +			return ret;
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +static int ov7251_get_frame_interval(struct v4l2_subdev *subdev,
>> +				     struct v4l2_subdev_frame_interval *fi)
>> +{
>> +	struct ov7251 *ov7251 = to_ov7251(subdev);
>> +
>> +	fi->interval = ov7251->current_mode->timeperframe;
>> +
>> +	return 0;
>> +}
>> +
>> +static int ov7251_set_frame_interval(struct v4l2_subdev *subdev,
>> +				     struct v4l2_subdev_frame_interval *fi)
>> +{
>> +	struct ov7251 *ov7251 = to_ov7251(subdev);
>> +	const struct ov7251_mode_info *new_mode;
>> +
>> +	new_mode = ov7251_find_mode_by_ival(ov7251, &fi->interval);
>> +
>> +	if (new_mode != ov7251->current_mode) {
>> +		int ret;
>> +
>> +		ret = v4l2_ctrl_s_ctrl_int64(ov7251->pixel_clock,
>> +					     new_mode->pixel_clock);
>> +		if (ret < 0)
>> +			return ret;
>> +
>> +		ret = v4l2_ctrl_s_ctrl(ov7251->link_freq,
>> +				       new_mode->link_freq);
>> +		if (ret < 0)
>> +			return ret;
>> +
>> +		ret = v4l2_ctrl_modify_range(ov7251->exposure,
>> +					     1, new_mode->exposure_max,
>> +					     1, new_mode->exposure_def);
>> +		if (ret < 0)
>> +			return ret;
>> +
>> +		ret = v4l2_ctrl_s_ctrl(ov7251->exposure,
>> +				       new_mode->exposure_def);
>> +		if (ret < 0)
>> +			return ret;
>> +
>> +		ret = v4l2_ctrl_s_ctrl(ov7251->gain, 16);
>> +		if (ret < 0)
>> +			return ret;
>> +
>> +		ov7251->current_mode = new_mode;
>> +	}
>> +
>> +	fi->interval = ov7251->current_mode->timeperframe;
>> +
>> +	return 0;
>> +}
>> +
>> +static const struct v4l2_subdev_core_ops ov7251_core_ops = {
>> +	.s_power = ov7251_s_power,
>> +};
>> +
>> +static const struct v4l2_subdev_video_ops ov7251_video_ops = {
>> +	.s_stream = ov7251_s_stream,
>> +	.g_frame_interval = ov7251_get_frame_interval,
>> +	.s_frame_interval = ov7251_set_frame_interval,
>> +};
>> +
>> +static const struct v4l2_subdev_pad_ops ov7251_subdev_pad_ops = {
>> +	.init_cfg = ov7251_entity_init_cfg,
>> +	.enum_mbus_code = ov7251_enum_mbus_code,
>> +	.enum_frame_size = ov7251_enum_frame_size,
>> +	.enum_frame_interval = ov7251_enum_frame_ival,
>> +	.get_fmt = ov7251_get_format,
>> +	.set_fmt = ov7251_set_format,
>> +	.get_selection = ov7251_get_selection,
>> +};
>> +
>> +static const struct v4l2_subdev_ops ov7251_subdev_ops = {
>> +	.core = &ov7251_core_ops,
>> +	.video = &ov7251_video_ops,
>> +	.pad = &ov7251_subdev_pad_ops,
>> +};
>> +
>> +static int ov7251_probe(struct i2c_client *client,
>> +			const struct i2c_device_id *id)
>> +{
>> +	struct device *dev = &client->dev;
>> +	struct fwnode_handle *endpoint;
>> +	struct ov7251 *ov7251;
>> +	u8 chip_id_high, chip_id_low, chip_rev;
>> +	u32 xclk_freq;
>> +	int ret;
>> +
>> +	ov7251 = devm_kzalloc(dev, sizeof(struct ov7251), GFP_KERNEL);
>> +	if (!ov7251)
>> +		return -ENOMEM;
>> +
>> +	ov7251->i2c_client = client;
>> +	ov7251->dev = dev;
>> +
>> +	endpoint = fwnode_graph_get_next_endpoint(dev_fwnode(dev), NULL);
>> +	if (!endpoint) {
>> +		dev_err(dev, "endpoint node not found\n");
>> +		return -EINVAL;
>> +	}
>> +
>> +	ret = v4l2_fwnode_endpoint_parse(endpoint, &ov7251->ep);
>> +	fwnode_handle_put(endpoint);
>> +	if (ret < 0) {
>> +		dev_err(dev, "parsing endpoint node failed\n");
>> +		return ret;
>> +	}
>> +
>> +	if (ov7251->ep.bus_type != V4L2_MBUS_CSI2) {
>> +		dev_err(dev, "invalid bus type (%u), must be CSI2 (%u)\n",
>> +			ov7251->ep.bus_type, V4L2_MBUS_CSI2);
>> +		return -EINVAL;
>> +	}
>> +
>> +	/* get system clock (xclk) */
>> +	ov7251->xclk = devm_clk_get(dev, "xclk");
>> +	if (IS_ERR(ov7251->xclk)) {
>> +		dev_err(dev, "could not get xclk");
>> +		return PTR_ERR(ov7251->xclk);
>> +	}
>> +
>> +	ret = of_property_read_u32(dev->of_node, "clock-frequency", &xclk_freq);
>> +	if (ret) {
>> +		dev_err(dev, "could not get xclk frequency\n");
>> +		return ret;
>> +	}
>> +
>> +	/* external clock must be 24MHz, allow 1% tolerance */
>> +	if (xclk_freq < 23760000 || xclk_freq > 24240000) {
>> +		dev_err(dev, "external clock frequency %u is not supported\n",
>> +			xclk_freq);
>> +		return -EINVAL;
>> +	}
>> +
>> +	ret = clk_set_rate(ov7251->xclk, xclk_freq);
>> +	if (ret) {
>> +		dev_err(dev, "could not set xclk frequency\n");
>> +		return ret;
>> +	}
>> +
>> +	ov7251->io_regulator = devm_regulator_get(dev, "vdddo");
>> +	if (IS_ERR(ov7251->io_regulator)) {
>> +		dev_err(dev, "cannot get io regulator\n");
>> +		return PTR_ERR(ov7251->io_regulator);
>> +	}
>> +
>> +	ret = regulator_set_voltage(ov7251->io_regulator,
>> +				    OV7251_VOLTAGE_DIGITAL_IO,
>> +				    OV7251_VOLTAGE_DIGITAL_IO);
> 
> Shouldn't this be accounted for in DT? I have to say I'm not an expert in
> this area, still the only other driver doing this is ov5645. And it's
> written by you. :-)

You are right, I'll remove set_voltage.

> 
>> +	if (ret < 0) {
>> +		dev_err(dev, "cannot set io voltage\n");
>> +		return ret;
>> +	}
>> +
>> +	ov7251->core_regulator = devm_regulator_get(dev, "vddd");
>> +	if (IS_ERR(ov7251->core_regulator)) {
>> +		dev_err(dev, "cannot get core regulator\n");
>> +		return PTR_ERR(ov7251->core_regulator);
>> +	}
>> +
>> +	ret = regulator_set_voltage(ov7251->core_regulator,
>> +				    OV7251_VOLTAGE_DIGITAL_CORE,
>> +				    OV7251_VOLTAGE_DIGITAL_CORE);
>> +	if (ret < 0) {
>> +		dev_err(dev, "cannot set core voltage\n");
>> +		return ret;
>> +	}
>> +
>> +	ov7251->analog_regulator = devm_regulator_get(dev, "vdda");
>> +	if (IS_ERR(ov7251->analog_regulator)) {
>> +		dev_err(dev, "cannot get analog regulator\n");
>> +		return PTR_ERR(ov7251->analog_regulator);
>> +	}
>> +
>> +	ret = regulator_set_voltage(ov7251->analog_regulator,
>> +				    OV7251_VOLTAGE_ANALOG,
>> +				    OV7251_VOLTAGE_ANALOG);
>> +	if (ret < 0) {
>> +		dev_err(dev, "cannot set analog voltage\n");
>> +		return ret;
>> +	}
>> +
>> +	ov7251->enable_gpio = devm_gpiod_get(dev, "enable", GPIOD_OUT_HIGH);
>> +	if (IS_ERR(ov7251->enable_gpio)) {
>> +		dev_err(dev, "cannot get enable gpio\n");
>> +		return PTR_ERR(ov7251->enable_gpio);
>> +	}
>> +
>> +	mutex_init(&ov7251->power_lock);
>> +
>> +	v4l2_ctrl_handler_init(&ov7251->ctrls, 7);
>> +	v4l2_ctrl_new_std(&ov7251->ctrls, &ov7251_ctrl_ops,
>> +			  V4L2_CID_HFLIP, 0, 1, 1, 0);
>> +	v4l2_ctrl_new_std(&ov7251->ctrls, &ov7251_ctrl_ops,
>> +			  V4L2_CID_VFLIP, 0, 1, 1, 0);
>> +	ov7251->exposure = v4l2_ctrl_new_std(&ov7251->ctrls, &ov7251_ctrl_ops,
>> +					     V4L2_CID_EXPOSURE, 1, 32, 1, 32);
>> +	ov7251->gain = v4l2_ctrl_new_std(&ov7251->ctrls, &ov7251_ctrl_ops,
>> +					 V4L2_CID_GAIN, 16, 1023, 1, 16);
>> +	v4l2_ctrl_new_std_menu_items(&ov7251->ctrls, &ov7251_ctrl_ops,
>> +				     V4L2_CID_TEST_PATTERN,
>> +				     ARRAY_SIZE(ov7251_test_pattern_menu) - 1,
>> +				     0, 0, ov7251_test_pattern_menu);
>> +	ov7251->pixel_clock = v4l2_ctrl_new_std(&ov7251->ctrls,
>> +						&ov7251_ctrl_ops,
>> +						V4L2_CID_PIXEL_RATE,
>> +						1, INT_MAX, 1, 1);
>> +	ov7251->link_freq = v4l2_ctrl_new_int_menu(&ov7251->ctrls,
>> +						   &ov7251_ctrl_ops,
>> +						   V4L2_CID_LINK_FREQ,
>> +						   ARRAY_SIZE(link_freq) - 1,
>> +						   0, link_freq);
>> +	if (ov7251->link_freq)
>> +		ov7251->link_freq->flags |= V4L2_CTRL_FLAG_READ_ONLY;
>> +
>> +	ov7251->sd.ctrl_handler = &ov7251->ctrls;
>> +
>> +	if (ov7251->ctrls.error) {
>> +		dev_err(dev, "%s: control initialization error %d\n",
>> +		       __func__, ov7251->ctrls.error);
>> +		ret = ov7251->ctrls.error;
>> +		goto free_ctrl;
>> +	}
>> +
>> +	v4l2_i2c_subdev_init(&ov7251->sd, client, &ov7251_subdev_ops);
>> +	ov7251->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
>> +	ov7251->pad.flags = MEDIA_PAD_FL_SOURCE;
>> +	ov7251->sd.dev = &client->dev;
>> +	ov7251->sd.entity.function = MEDIA_ENT_F_CAM_SENSOR;
>> +
>> +	ret = media_entity_pads_init(&ov7251->sd.entity, 1, &ov7251->pad);
>> +	if (ret < 0) {
>> +		dev_err(dev, "could not register media entity\n");
>> +		goto free_ctrl;
>> +	}
>> +
>> +	ret = ov7251_s_power(&ov7251->sd, true);
>> +	if (ret < 0) {
>> +		dev_err(dev, "could not power up OV7251\n");
>> +		goto free_entity;
>> +	}
>> +
>> +	ret = ov7251_read_reg(ov7251, OV7251_CHIP_ID_HIGH, &chip_id_high);
>> +	if (ret < 0 || chip_id_high != OV7251_CHIP_ID_HIGH_BYTE) {
>> +		dev_err(dev, "could not read ID high\n");
>> +		ret = -ENODEV;
>> +		goto power_down;
>> +	}
>> +	ret = ov7251_read_reg(ov7251, OV7251_CHIP_ID_LOW, &chip_id_low);
>> +	if (ret < 0 || chip_id_low != OV7251_CHIP_ID_LOW_BYTE) {
>> +		dev_err(dev, "could not read ID low\n");
>> +		ret = -ENODEV;
>> +		goto power_down;
>> +	}
>> +
>> +	ret = ov7251_read_reg(ov7251, OV7251_SC_GP_IO_IN1, &chip_rev);
>> +	if (ret < 0) {
>> +		dev_err(dev, "could not read revision\n");
>> +		ret = -ENODEV;
>> +		goto power_down;
>> +	}
>> +	chip_rev >>= 4;
>> +
>> +	dev_info(dev, "OV7251 revision %x (%s) detected at address 0x%02x\n",
>> +		 chip_rev,
>> +		 chip_rev == 0x4 ? "1A / 1B" :
>> +		 chip_rev == 0x5 ? "1C / 1D" :
>> +		 chip_rev == 0x6 ? "1E" :
>> +		 chip_rev == 0x7 ? "1F" : "unknown",
>> +		 client->addr);
>> +
>> +	ret = ov7251_read_reg(ov7251, OV7251_PRE_ISP_00,
>> +			      &ov7251->pre_isp_00);
>> +	if (ret < 0) {
>> +		dev_err(dev, "could not read test pattern value\n");
>> +		ret = -ENODEV;
>> +		goto power_down;
>> +	}
>> +
>> +	ret = ov7251_read_reg(ov7251, OV7251_TIMING_FORMAT1,
>> +			      &ov7251->timing_format1);
>> +	if (ret < 0) {
>> +		dev_err(dev, "could not read vflip value\n");
>> +		ret = -ENODEV;
>> +		goto power_down;
>> +	}
>> +
>> +	ret = ov7251_read_reg(ov7251, OV7251_TIMING_FORMAT2,
>> +			      &ov7251->timing_format2);
>> +	if (ret < 0) {
>> +		dev_err(dev, "could not read hflip value\n");
>> +		ret = -ENODEV;
>> +		goto power_down;
>> +	}
>> +
>> +	ov7251_s_power(&ov7251->sd, false);
>> +
>> +	ret = v4l2_async_register_subdev(&ov7251->sd);
>> +	if (ret < 0) {
>> +		dev_err(dev, "could not register v4l2 device\n");
>> +		goto free_entity;
>> +	}
>> +
>> +	ov7251_entity_init_cfg(&ov7251->sd, NULL);
>> +
>> +	return 0;
>> +
>> +power_down:
>> +	ov7251_s_power(&ov7251->sd, false);
>> +free_entity:
>> +	media_entity_cleanup(&ov7251->sd.entity);
>> +free_ctrl:
>> +	v4l2_ctrl_handler_free(&ov7251->ctrls);
>> +	mutex_destroy(&ov7251->power_lock);
>> +
>> +	return ret;
>> +}
>> +
>> +static int ov7251_remove(struct i2c_client *client)
>> +{
>> +	struct v4l2_subdev *sd = i2c_get_clientdata(client);
>> +	struct ov7251 *ov7251 = to_ov7251(sd);
>> +
>> +	v4l2_async_unregister_subdev(&ov7251->sd);
>> +	media_entity_cleanup(&ov7251->sd.entity);
>> +	v4l2_ctrl_handler_free(&ov7251->ctrls);
>> +	mutex_destroy(&ov7251->power_lock);
>> +
>> +	return 0;
>> +}
>> +
>> +static const struct i2c_device_id ov7251_id[] = {
>> +	{ "ov7251", 0 },
>> +	{}
>> +};
>> +MODULE_DEVICE_TABLE(i2c, ov7251_id);
>> +
>> +static const struct of_device_id ov7251_of_match[] = {
>> +	{ .compatible = "ovti,ov7251" },
>> +	{ /* sentinel */ }
>> +};
>> +MODULE_DEVICE_TABLE(of, ov7251_of_match);
>> +
>> +static struct i2c_driver ov7251_i2c_driver = {
>> +	.driver = {
>> +		.of_match_table = of_match_ptr(ov7251_of_match),
>> +		.name  = "ov7251",
>> +	},
>> +	.probe  = ov7251_probe,
>> +	.remove = ov7251_remove,
>> +	.id_table = ov7251_id,
>> +};
>> +
>> +module_i2c_driver(ov7251_i2c_driver);
>> +
>> +MODULE_DESCRIPTION("Omnivision OV7251 Camera Driver");
>> +MODULE_AUTHOR("Todor Tomov <todor.tomov@linaro.org>");
>> +MODULE_LICENSE("GPL v2");
>
Sakari Ailus April 17, 2018, 8:10 p.m. UTC | #9
Hi Todor,

On Tue, Apr 17, 2018 at 06:32:07PM +0300, Todor Tomov wrote:
...
> >> +static int ov7251_regulators_enable(struct ov7251 *ov7251)
> >> +{
> >> +	int ret;
> >> +
> >> +	ret = regulator_enable(ov7251->io_regulator);
> > 
> > How about regulator_bulk_enable() here, and bulk_disable below?
> 
> I'm not using the bulk API because usually there is a power up
> sequence and intervals that must be followed. For this sensor
> the only constraint is that core regulator must be enabled
> after io regulator. But the bulk API doesn't guarantee the
> order.

Could you add a comment explaining this? Otherwise it won't take long until
someone "fixes" the code.

...

> >> +static int ov7251_read_reg(struct ov7251 *ov7251, u16 reg, u8 *val)
> >> +{
> >> +	u8 regbuf[2];
> >> +	int ret;
> >> +
> >> +	regbuf[0] = reg >> 8;
> >> +	regbuf[1] = reg & 0xff;
> >> +
> >> +	ret = i2c_master_send(ov7251->i2c_client, regbuf, 2);
> >> +	if (ret < 0) {
> >> +		dev_err(ov7251->dev, "%s: write reg error %d: reg=%x\n",
> >> +			__func__, ret, reg);
> >> +		return ret;
> >> +	}
> >> +
> >> +	ret = i2c_master_recv(ov7251->i2c_client, val, 1);
> >> +	if (ret < 0) {
> >> +		dev_err(ov7251->dev, "%s: read reg error %d: reg=%x\n",
> >> +			__func__, ret, reg);
> >> +		return ret;
> >> +	}
> >> +
> >> +	return 0;
> >> +}
> >> +
> >> +static int ov7251_set_exposure(struct ov7251 *ov7251, s32 exposure)
> >> +{
> >> +	int ret;
> >> +
> >> +	ret = ov7251_write_reg(ov7251, OV7251_AEC_EXPO_0,
> >> +			       (exposure & 0xf000) >> 12);
> >> +	if (ret < 0)
> >> +		return ret;
> >> +
> >> +	ret = ov7251_write_reg(ov7251, OV7251_AEC_EXPO_1,
> >> +			       (exposure & 0x0ff0) >> 4);
> >> +	if (ret < 0)
> >> +		return ret;
> >> +
> >> +	return ov7251_write_reg(ov7251, OV7251_AEC_EXPO_2,
> >> +				(exposure & 0x000f) << 4);
> > 
> > It's not a good idea to access multi-octet registers separately. Depending
> > on the hardware implementation, the hardware could latch the value in the
> > middle of an update. This is only an issue during streaming in practice
> > though.
> 
> Good point. The sensor has a group write functionality which can be used
> to solve this but in general is intended
> to apply a group of exposure and gain settings in the same frame. However
> it seems to me that is not possible to use this functionality efficiently
> with the currently available user controls. The group write is configured
> using an id for a group of commands. So if we configure exposure and gain
> separately (a group for each):
> - if the driver uses same group id for exposure and gain, if both controls
>   are received in one frame the second will overwrite the first (the
>   first will not be applied);
> - if the driver uses different group id for exposure and gain, it will not
>   be possible for the user to change exposure and gain in the same frame
>   (as some exposure algorithms do) and it will lead again to frames with
>   "incorrect" brightness.
> 
> To do this correctly we will have to extend the API to be able to apply
> exposure and gain "atomically":
> - a single user control which will set both exposure and gain and it will
>   guarantee that they will be applied in the same frame;
> - some kind of: begin, set exposure, set gain, end, launch -API
> 
> What do you think?
> 
> Actually, I'm a little bit surprised that I didn't find anything
> like this already. And there are already a number of sensor drivers
> which update more than one register to set exposure.

The latter of the two would be preferred as it isn't limited to exposure
and gain only. Still, you could address the problem for this driver by
simply writing the register in a single transaction.

...

> >> +static int ov7251_enum_mbus_code(struct v4l2_subdev *sd,
> >> +				 struct v4l2_subdev_pad_config *cfg,
> >> +				 struct v4l2_subdev_mbus_code_enum *code)
> >> +{
> >> +	if (code->index > 0)
> >> +		return -EINVAL;
> >> +
> >> +	code->code = MEDIA_BUS_FMT_SBGGR10_1X10;
> >> +
> >> +	return 0;
> >> +}
> >> +
> >> +static int ov7251_enum_frame_size(struct v4l2_subdev *subdev,
> >> +				  struct v4l2_subdev_pad_config *cfg,
> >> +				  struct v4l2_subdev_frame_size_enum *fse)
> >> +{
> >> +	if (fse->code != MEDIA_BUS_FMT_SBGGR10_1X10)
> > 
> > Can the flip controls affect the media bus code? Either take this into
> > account or remove flip controls.
> 
> This sensor is black and white (monochrome). I have used BGGR because I
> didn't find any monochrome format amongst the Bayer formats. Looking
> again at it now, probably we have to use MEDIA_BUS_FMT_Y10_1X10?

:-) Yes, that's the right media bus code AFAICT.

> 
> However I cannot find a suitable pixel format too (to be used by the
> platform driver) as the output is MIPI10 (same encoding as
> V4L2_PIX_FMT_SBGGR10P but monochrome) and V4L2_PIX_FMT_Y10BPACK has
> different encoding. So it seems to me that I will have to add another
> pixel format, right?

Yes, please.
Todor Tomov April 24, 2018, 12:49 p.m. UTC | #10
Hi Sakari,

On 17.04.2018 23:10, Sakari Ailus wrote:
> Hi Todor,
> 
> On Tue, Apr 17, 2018 at 06:32:07PM +0300, Todor Tomov wrote:
> ...
>>>> +static int ov7251_regulators_enable(struct ov7251 *ov7251)
>>>> +{
>>>> +	int ret;
>>>> +
>>>> +	ret = regulator_enable(ov7251->io_regulator);
>>>
>>> How about regulator_bulk_enable() here, and bulk_disable below?
>>
>> I'm not using the bulk API because usually there is a power up
>> sequence and intervals that must be followed. For this sensor
>> the only constraint is that core regulator must be enabled
>> after io regulator. But the bulk API doesn't guarantee the
>> order.
> 
> Could you add a comment explaining this? Otherwise it won't take long until
> someone "fixes" the code.

Sure :D
I'm adding a comment.

> 
> ...
> 
>>>> +static int ov7251_read_reg(struct ov7251 *ov7251, u16 reg, u8 *val)
>>>> +{
>>>> +	u8 regbuf[2];
>>>> +	int ret;
>>>> +
>>>> +	regbuf[0] = reg >> 8;
>>>> +	regbuf[1] = reg & 0xff;
>>>> +
>>>> +	ret = i2c_master_send(ov7251->i2c_client, regbuf, 2);
>>>> +	if (ret < 0) {
>>>> +		dev_err(ov7251->dev, "%s: write reg error %d: reg=%x\n",
>>>> +			__func__, ret, reg);
>>>> +		return ret;
>>>> +	}
>>>> +
>>>> +	ret = i2c_master_recv(ov7251->i2c_client, val, 1);
>>>> +	if (ret < 0) {
>>>> +		dev_err(ov7251->dev, "%s: read reg error %d: reg=%x\n",
>>>> +			__func__, ret, reg);
>>>> +		return ret;
>>>> +	}
>>>> +
>>>> +	return 0;
>>>> +}
>>>> +
>>>> +static int ov7251_set_exposure(struct ov7251 *ov7251, s32 exposure)
>>>> +{
>>>> +	int ret;
>>>> +
>>>> +	ret = ov7251_write_reg(ov7251, OV7251_AEC_EXPO_0,
>>>> +			       (exposure & 0xf000) >> 12);
>>>> +	if (ret < 0)
>>>> +		return ret;
>>>> +
>>>> +	ret = ov7251_write_reg(ov7251, OV7251_AEC_EXPO_1,
>>>> +			       (exposure & 0x0ff0) >> 4);
>>>> +	if (ret < 0)
>>>> +		return ret;
>>>> +
>>>> +	return ov7251_write_reg(ov7251, OV7251_AEC_EXPO_2,
>>>> +				(exposure & 0x000f) << 4);
>>>
>>> It's not a good idea to access multi-octet registers separately. Depending
>>> on the hardware implementation, the hardware could latch the value in the
>>> middle of an update. This is only an issue during streaming in practice
>>> though.
>>
>> Good point. The sensor has a group write functionality which can be used
>> to solve this but in general is intended
>> to apply a group of exposure and gain settings in the same frame. However
>> it seems to me that is not possible to use this functionality efficiently
>> with the currently available user controls. The group write is configured
>> using an id for a group of commands. So if we configure exposure and gain
>> separately (a group for each):
>> - if the driver uses same group id for exposure and gain, if both controls
>>   are received in one frame the second will overwrite the first (the
>>   first will not be applied);
>> - if the driver uses different group id for exposure and gain, it will not
>>   be possible for the user to change exposure and gain in the same frame
>>   (as some exposure algorithms do) and it will lead again to frames with
>>   "incorrect" brightness.
>>
>> To do this correctly we will have to extend the API to be able to apply
>> exposure and gain "atomically":
>> - a single user control which will set both exposure and gain and it will
>>   guarantee that they will be applied in the same frame;
>> - some kind of: begin, set exposure, set gain, end, launch -API
>>
>> What do you think?
>>
>> Actually, I'm a little bit surprised that I didn't find anything
>> like this already. And there are already a number of sensor drivers
>> which update more than one register to set exposure.
> 
> The latter of the two would be preferred as it isn't limited to exposure
> and gain only. Still, you could address the problem for this driver by
> simply writing the register in a single transaction.

Thanks for suggestion. I've tried the single transaction, I will send the
next version of the driver shortly.
diff mbox

Patch

diff --git a/drivers/media/i2c/Kconfig b/drivers/media/i2c/Kconfig
index 541f0d28..89aecb3 100644
--- a/drivers/media/i2c/Kconfig
+++ b/drivers/media/i2c/Kconfig
@@ -688,6 +688,19 @@  config VIDEO_OV5695
 	  To compile this driver as a module, choose M here: the
 	  module will be called ov5695.
 
+config VIDEO_OV7251
+	tristate "OmniVision OV7251 sensor support"
+	depends on OF
+	depends on I2C && VIDEO_V4L2 && VIDEO_V4L2_SUBDEV_API
+	depends on MEDIA_CAMERA_SUPPORT
+	select V4L2_FWNODE
+	---help---
+	  This is a Video4Linux2 sensor-level driver for the OmniVision
+	  OV7251 camera.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called ov7251.
+
 config VIDEO_OV772X
 	tristate "OmniVision OV772x sensor support"
 	depends on I2C && VIDEO_V4L2
diff --git a/drivers/media/i2c/Makefile b/drivers/media/i2c/Makefile
index ea34aee..c8585b1 100644
--- a/drivers/media/i2c/Makefile
+++ b/drivers/media/i2c/Makefile
@@ -70,6 +70,7 @@  obj-$(CONFIG_VIDEO_OV5647) += ov5647.o
 obj-$(CONFIG_VIDEO_OV5670) += ov5670.o
 obj-$(CONFIG_VIDEO_OV5695) += ov5695.o
 obj-$(CONFIG_VIDEO_OV6650) += ov6650.o
+obj-$(CONFIG_VIDEO_OV7251) += ov7251.o
 obj-$(CONFIG_VIDEO_OV7640) += ov7640.o
 obj-$(CONFIG_VIDEO_OV7670) += ov7670.o
 obj-$(CONFIG_VIDEO_OV772X) += ov772x.o
diff --git a/drivers/media/i2c/ov7251.c b/drivers/media/i2c/ov7251.c
new file mode 100644
index 0000000..7b401a9
--- /dev/null
+++ b/drivers/media/i2c/ov7251.c
@@ -0,0 +1,1494 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Driver for the OV7251 camera sensor.
+ *
+ * Copyright (c) 2017-2018, The Linux Foundation. All rights reserved.
+ * Copyright (c) 2017-2018, Linaro Ltd.
+ */
+
+#include <linux/bitops.h>
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/gpio/consumer.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_graph.h>
+#include <linux/regulator/consumer.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <media/v4l2-ctrls.h>
+#include <media/v4l2-fwnode.h>
+#include <media/v4l2-subdev.h>
+
+#define OV7251_VOLTAGE_ANALOG               2800000
+#define OV7251_VOLTAGE_DIGITAL_CORE         1500000
+#define OV7251_VOLTAGE_DIGITAL_IO           1800000
+
+#define OV7251_SC_MODE_SELECT		0x0100
+#define OV7251_SC_MODE_SELECT_SW_STANDBY	0x0
+#define OV7251_SC_MODE_SELECT_STREAMING		0x1
+
+#define OV7251_CHIP_ID_HIGH		0x300a
+#define OV7251_CHIP_ID_HIGH_BYTE	0x77
+#define OV7251_CHIP_ID_LOW		0x300b
+#define OV7251_CHIP_ID_LOW_BYTE		0x50
+#define OV7251_SC_GP_IO_IN1		0x3029
+#define OV7251_AEC_EXPO_0		0x3500
+#define OV7251_AEC_EXPO_1		0x3501
+#define OV7251_AEC_EXPO_2		0x3502
+#define OV7251_AEC_AGC_ADJ_0		0x350a
+#define OV7251_AEC_AGC_ADJ_1		0x350b
+#define OV7251_TIMING_FORMAT1		0x3820
+#define OV7251_TIMING_FORMAT1_VFLIP	BIT(2)
+#define OV7251_TIMING_FORMAT2		0x3821
+#define OV7251_TIMING_FORMAT2_MIRROR	BIT(2)
+#define OV7251_PRE_ISP_00		0x5e00
+#define OV7251_PRE_ISP_00_TEST_PATTERN	BIT(7)
+
+struct reg_value {
+	u16 reg;
+	u8 val;
+};
+
+struct ov7251_mode_info {
+	u32 width;
+	u32 height;
+	const struct reg_value *data;
+	u32 data_size;
+	u32 pixel_clock;
+	u32 link_freq;
+	u16 exposure_max;
+	u16 exposure_def;
+	struct v4l2_fract timeperframe;
+};
+
+struct ov7251 {
+	struct i2c_client *i2c_client;
+	struct device *dev;
+	struct v4l2_subdev sd;
+	struct media_pad pad;
+	struct v4l2_fwnode_endpoint ep;
+	struct v4l2_mbus_framefmt fmt;
+	struct v4l2_rect crop;
+	struct clk *xclk;
+
+	struct regulator *io_regulator;
+	struct regulator *core_regulator;
+	struct regulator *analog_regulator;
+
+	const struct ov7251_mode_info *current_mode;
+
+	struct v4l2_ctrl_handler ctrls;
+	struct v4l2_ctrl *pixel_clock;
+	struct v4l2_ctrl *link_freq;
+	struct v4l2_ctrl *exposure;
+	struct v4l2_ctrl *gain;
+
+	/* Cached register values */
+	u8 aec_pk_manual;
+	u8 pre_isp_00;
+	u8 timing_format1;
+	u8 timing_format2;
+
+	struct mutex power_lock; /* lock to protect power state */
+	bool power_on;
+
+	struct gpio_desc *enable_gpio;
+};
+
+static inline struct ov7251 *to_ov7251(struct v4l2_subdev *sd)
+{
+	return container_of(sd, struct ov7251, sd);
+}
+
+static const struct reg_value ov7251_global_init_setting[] = {
+	{ 0x0103, 0x01 },
+	{ 0x303b, 0x02 },
+};
+
+static const struct reg_value ov7251_setting_vga_30fps[] = {
+	{ 0x3005, 0x00 },
+	{ 0x3012, 0xc0 },
+	{ 0x3013, 0xd2 },
+	{ 0x3014, 0x04 },
+	{ 0x3016, 0xf0 },
+	{ 0x3017, 0xf0 },
+	{ 0x3018, 0xf0 },
+	{ 0x301a, 0xf0 },
+	{ 0x301b, 0xf0 },
+	{ 0x301c, 0xf0 },
+	{ 0x3023, 0x05 },
+	{ 0x3037, 0xf0 },
+	{ 0x3098, 0x04 }, /* pll2 pre divider */
+	{ 0x3099, 0x28 }, /* pll2 multiplier */
+	{ 0x309a, 0x05 }, /* pll2 sys divider */
+	{ 0x309b, 0x04 }, /* pll2 adc divider */
+	{ 0x309d, 0x00 }, /* pll2 divider */
+	{ 0x30b0, 0x0a }, /* pll1 pix divider */
+	{ 0x30b1, 0x01 }, /* pll1 divider */
+	{ 0x30b3, 0x64 }, /* pll1 multiplier */
+	{ 0x30b4, 0x03 }, /* pll1 pre divider */
+	{ 0x30b5, 0x05 }, /* pll1 mipi divider */
+	{ 0x3106, 0xda },
+	{ 0x3503, 0x07 },
+	{ 0x3509, 0x10 },
+	{ 0x3600, 0x1c },
+	{ 0x3602, 0x62 },
+	{ 0x3620, 0xb7 },
+	{ 0x3622, 0x04 },
+	{ 0x3626, 0x21 },
+	{ 0x3627, 0x30 },
+	{ 0x3630, 0x44 },
+	{ 0x3631, 0x35 },
+	{ 0x3634, 0x60 },
+	{ 0x3636, 0x00 },
+	{ 0x3662, 0x01 },
+	{ 0x3663, 0x70 },
+	{ 0x3664, 0x50 },
+	{ 0x3666, 0x0a },
+	{ 0x3669, 0x1a },
+	{ 0x366a, 0x00 },
+	{ 0x366b, 0x50 },
+	{ 0x3673, 0x01 },
+	{ 0x3674, 0xff },
+	{ 0x3675, 0x03 },
+	{ 0x3705, 0xc1 },
+	{ 0x3709, 0x40 },
+	{ 0x373c, 0x08 },
+	{ 0x3742, 0x00 },
+	{ 0x3757, 0xb3 },
+	{ 0x3788, 0x00 },
+	{ 0x37a8, 0x01 },
+	{ 0x37a9, 0xc0 },
+	{ 0x3800, 0x00 },
+	{ 0x3801, 0x04 },
+	{ 0x3802, 0x00 },
+	{ 0x3803, 0x04 },
+	{ 0x3804, 0x02 },
+	{ 0x3805, 0x8b },
+	{ 0x3806, 0x01 },
+	{ 0x3807, 0xeb },
+	{ 0x3808, 0x02 }, /* width high */
+	{ 0x3809, 0x80 }, /* width low */
+	{ 0x380a, 0x01 }, /* height high */
+	{ 0x380b, 0xe0 }, /* height low */
+	{ 0x380c, 0x03 }, /* total horiz timing high */
+	{ 0x380d, 0xa0 }, /* total horiz timing low */
+	{ 0x380e, 0x06 }, /* total vertical timing high */
+	{ 0x380f, 0xbc }, /* total vertical timing low */
+	{ 0x3810, 0x00 },
+	{ 0x3811, 0x04 },
+	{ 0x3812, 0x00 },
+	{ 0x3813, 0x05 },
+	{ 0x3814, 0x11 },
+	{ 0x3815, 0x11 },
+	{ 0x3820, 0x40 },
+	{ 0x3821, 0x00 },
+	{ 0x382f, 0x0e },
+	{ 0x3832, 0x00 },
+	{ 0x3833, 0x05 },
+	{ 0x3834, 0x00 },
+	{ 0x3835, 0x0c },
+	{ 0x3837, 0x00 },
+	{ 0x3b80, 0x00 },
+	{ 0x3b81, 0xa5 },
+	{ 0x3b82, 0x10 },
+	{ 0x3b83, 0x00 },
+	{ 0x3b84, 0x08 },
+	{ 0x3b85, 0x00 },
+	{ 0x3b86, 0x01 },
+	{ 0x3b87, 0x00 },
+	{ 0x3b88, 0x00 },
+	{ 0x3b89, 0x00 },
+	{ 0x3b8a, 0x00 },
+	{ 0x3b8b, 0x05 },
+	{ 0x3b8c, 0x00 },
+	{ 0x3b8d, 0x00 },
+	{ 0x3b8e, 0x00 },
+	{ 0x3b8f, 0x1a },
+	{ 0x3b94, 0x05 },
+	{ 0x3b95, 0xf2 },
+	{ 0x3b96, 0x40 },
+	{ 0x3c00, 0x89 },
+	{ 0x3c01, 0x63 },
+	{ 0x3c02, 0x01 },
+	{ 0x3c03, 0x00 },
+	{ 0x3c04, 0x00 },
+	{ 0x3c05, 0x03 },
+	{ 0x3c06, 0x00 },
+	{ 0x3c07, 0x06 },
+	{ 0x3c0c, 0x01 },
+	{ 0x3c0d, 0xd0 },
+	{ 0x3c0e, 0x02 },
+	{ 0x3c0f, 0x0a },
+	{ 0x4001, 0x42 },
+	{ 0x4004, 0x04 },
+	{ 0x4005, 0x00 },
+	{ 0x404e, 0x01 },
+	{ 0x4300, 0xff },
+	{ 0x4301, 0x00 },
+	{ 0x4315, 0x00 },
+	{ 0x4501, 0x48 },
+	{ 0x4600, 0x00 },
+	{ 0x4601, 0x4e },
+	{ 0x4801, 0x0f },
+	{ 0x4806, 0x0f },
+	{ 0x4819, 0xaa },
+	{ 0x4823, 0x3e },
+	{ 0x4837, 0x19 },
+	{ 0x4a0d, 0x00 },
+	{ 0x4a47, 0x7f },
+	{ 0x4a49, 0xf0 },
+	{ 0x4a4b, 0x30 },
+	{ 0x5000, 0x85 },
+	{ 0x5001, 0x80 },
+};
+
+static const struct reg_value ov7251_setting_vga_60fps[] = {
+	{ 0x3005, 0x00 },
+	{ 0x3012, 0xc0 },
+	{ 0x3013, 0xd2 },
+	{ 0x3014, 0x04 },
+	{ 0x3016, 0x10 },
+	{ 0x3017, 0x00 },
+	{ 0x3018, 0x00 },
+	{ 0x301a, 0x00 },
+	{ 0x301b, 0x00 },
+	{ 0x301c, 0x00 },
+	{ 0x3023, 0x05 },
+	{ 0x3037, 0xf0 },
+	{ 0x3098, 0x04 }, /* pll2 pre divider */
+	{ 0x3099, 0x28 }, /* pll2 multiplier */
+	{ 0x309a, 0x05 }, /* pll2 sys divider */
+	{ 0x309b, 0x04 }, /* pll2 adc divider */
+	{ 0x309d, 0x00 }, /* pll2 divider */
+	{ 0x30b0, 0x0a }, /* pll1 pix divider */
+	{ 0x30b1, 0x01 }, /* pll1 divider */
+	{ 0x30b3, 0x64 }, /* pll1 multiplier */
+	{ 0x30b4, 0x03 }, /* pll1 pre divider */
+	{ 0x30b5, 0x05 }, /* pll1 mipi divider */
+	{ 0x3106, 0xda },
+	{ 0x3503, 0x07 },
+	{ 0x3509, 0x10 },
+	{ 0x3600, 0x1c },
+	{ 0x3602, 0x62 },
+	{ 0x3620, 0xb7 },
+	{ 0x3622, 0x04 },
+	{ 0x3626, 0x21 },
+	{ 0x3627, 0x30 },
+	{ 0x3630, 0x44 },
+	{ 0x3631, 0x35 },
+	{ 0x3634, 0x60 },
+	{ 0x3636, 0x00 },
+	{ 0x3662, 0x01 },
+	{ 0x3663, 0x70 },
+	{ 0x3664, 0x50 },
+	{ 0x3666, 0x0a },
+	{ 0x3669, 0x1a },
+	{ 0x366a, 0x00 },
+	{ 0x366b, 0x50 },
+	{ 0x3673, 0x01 },
+	{ 0x3674, 0xff },
+	{ 0x3675, 0x03 },
+	{ 0x3705, 0xc1 },
+	{ 0x3709, 0x40 },
+	{ 0x373c, 0x08 },
+	{ 0x3742, 0x00 },
+	{ 0x3757, 0xb3 },
+	{ 0x3788, 0x00 },
+	{ 0x37a8, 0x01 },
+	{ 0x37a9, 0xc0 },
+	{ 0x3800, 0x00 },
+	{ 0x3801, 0x04 },
+	{ 0x3802, 0x00 },
+	{ 0x3803, 0x04 },
+	{ 0x3804, 0x02 },
+	{ 0x3805, 0x8b },
+	{ 0x3806, 0x01 },
+	{ 0x3807, 0xeb },
+	{ 0x3808, 0x02 }, /* width high */
+	{ 0x3809, 0x80 }, /* width low */
+	{ 0x380a, 0x01 }, /* height high */
+	{ 0x380b, 0xe0 }, /* height low */
+	{ 0x380c, 0x03 }, /* total horiz timing high */
+	{ 0x380d, 0xa0 }, /* total horiz timing low */
+	{ 0x380e, 0x03 }, /* total vertical timing high */
+	{ 0x380f, 0x5c }, /* total vertical timing low */
+	{ 0x3810, 0x00 },
+	{ 0x3811, 0x04 },
+	{ 0x3812, 0x00 },
+	{ 0x3813, 0x05 },
+	{ 0x3814, 0x11 },
+	{ 0x3815, 0x11 },
+	{ 0x3820, 0x40 },
+	{ 0x3821, 0x00 },
+	{ 0x382f, 0x0e },
+	{ 0x3832, 0x00 },
+	{ 0x3833, 0x05 },
+	{ 0x3834, 0x00 },
+	{ 0x3835, 0x0c },
+	{ 0x3837, 0x00 },
+	{ 0x3b80, 0x00 },
+	{ 0x3b81, 0xa5 },
+	{ 0x3b82, 0x10 },
+	{ 0x3b83, 0x00 },
+	{ 0x3b84, 0x08 },
+	{ 0x3b85, 0x00 },
+	{ 0x3b86, 0x01 },
+	{ 0x3b87, 0x00 },
+	{ 0x3b88, 0x00 },
+	{ 0x3b89, 0x00 },
+	{ 0x3b8a, 0x00 },
+	{ 0x3b8b, 0x05 },
+	{ 0x3b8c, 0x00 },
+	{ 0x3b8d, 0x00 },
+	{ 0x3b8e, 0x00 },
+	{ 0x3b8f, 0x1a },
+	{ 0x3b94, 0x05 },
+	{ 0x3b95, 0xf2 },
+	{ 0x3b96, 0x40 },
+	{ 0x3c00, 0x89 },
+	{ 0x3c01, 0x63 },
+	{ 0x3c02, 0x01 },
+	{ 0x3c03, 0x00 },
+	{ 0x3c04, 0x00 },
+	{ 0x3c05, 0x03 },
+	{ 0x3c06, 0x00 },
+	{ 0x3c07, 0x06 },
+	{ 0x3c0c, 0x01 },
+	{ 0x3c0d, 0xd0 },
+	{ 0x3c0e, 0x02 },
+	{ 0x3c0f, 0x0a },
+	{ 0x4001, 0x42 },
+	{ 0x4004, 0x04 },
+	{ 0x4005, 0x00 },
+	{ 0x404e, 0x01 },
+	{ 0x4300, 0xff },
+	{ 0x4301, 0x00 },
+	{ 0x4315, 0x00 },
+	{ 0x4501, 0x48 },
+	{ 0x4600, 0x00 },
+	{ 0x4601, 0x4e },
+	{ 0x4801, 0x0f },
+	{ 0x4806, 0x0f },
+	{ 0x4819, 0xaa },
+	{ 0x4823, 0x3e },
+	{ 0x4837, 0x19 },
+	{ 0x4a0d, 0x00 },
+	{ 0x4a47, 0x7f },
+	{ 0x4a49, 0xf0 },
+	{ 0x4a4b, 0x30 },
+	{ 0x5000, 0x85 },
+	{ 0x5001, 0x80 },
+};
+
+static const struct reg_value ov7251_setting_vga_90fps[] = {
+	{ 0x3005, 0x00 },
+	{ 0x3012, 0xc0 },
+	{ 0x3013, 0xd2 },
+	{ 0x3014, 0x04 },
+	{ 0x3016, 0x10 },
+	{ 0x3017, 0x00 },
+	{ 0x3018, 0x00 },
+	{ 0x301a, 0x00 },
+	{ 0x301b, 0x00 },
+	{ 0x301c, 0x00 },
+	{ 0x3023, 0x05 },
+	{ 0x3037, 0xf0 },
+	{ 0x3098, 0x04 }, /* pll2 pre divider */
+	{ 0x3099, 0x28 }, /* pll2 multiplier */
+	{ 0x309a, 0x05 }, /* pll2 sys divider */
+	{ 0x309b, 0x04 }, /* pll2 adc divider */
+	{ 0x309d, 0x00 }, /* pll2 divider */
+	{ 0x30b0, 0x0a }, /* pll1 pix divider */
+	{ 0x30b1, 0x01 }, /* pll1 divider */
+	{ 0x30b3, 0x64 }, /* pll1 multiplier */
+	{ 0x30b4, 0x03 }, /* pll1 pre divider */
+	{ 0x30b5, 0x05 }, /* pll1 mipi divider */
+	{ 0x3106, 0xda },
+	{ 0x3503, 0x07 },
+	{ 0x3509, 0x10 },
+	{ 0x3600, 0x1c },
+	{ 0x3602, 0x62 },
+	{ 0x3620, 0xb7 },
+	{ 0x3622, 0x04 },
+	{ 0x3626, 0x21 },
+	{ 0x3627, 0x30 },
+	{ 0x3630, 0x44 },
+	{ 0x3631, 0x35 },
+	{ 0x3634, 0x60 },
+	{ 0x3636, 0x00 },
+	{ 0x3662, 0x01 },
+	{ 0x3663, 0x70 },
+	{ 0x3664, 0x50 },
+	{ 0x3666, 0x0a },
+	{ 0x3669, 0x1a },
+	{ 0x366a, 0x00 },
+	{ 0x366b, 0x50 },
+	{ 0x3673, 0x01 },
+	{ 0x3674, 0xff },
+	{ 0x3675, 0x03 },
+	{ 0x3705, 0xc1 },
+	{ 0x3709, 0x40 },
+	{ 0x373c, 0x08 },
+	{ 0x3742, 0x00 },
+	{ 0x3757, 0xb3 },
+	{ 0x3788, 0x00 },
+	{ 0x37a8, 0x01 },
+	{ 0x37a9, 0xc0 },
+	{ 0x3800, 0x00 },
+	{ 0x3801, 0x04 },
+	{ 0x3802, 0x00 },
+	{ 0x3803, 0x04 },
+	{ 0x3804, 0x02 },
+	{ 0x3805, 0x8b },
+	{ 0x3806, 0x01 },
+	{ 0x3807, 0xeb },
+	{ 0x3808, 0x02 }, /* width high */
+	{ 0x3809, 0x80 }, /* width low */
+	{ 0x380a, 0x01 }, /* height high */
+	{ 0x380b, 0xe0 }, /* height low */
+	{ 0x380c, 0x03 }, /* total horiz timing high */
+	{ 0x380d, 0xa0 }, /* total horiz timing low */
+	{ 0x380e, 0x02 }, /* total vertical timing high */
+	{ 0x380f, 0x3c }, /* total vertical timing low */
+	{ 0x3810, 0x00 },
+	{ 0x3811, 0x04 },
+	{ 0x3812, 0x00 },
+	{ 0x3813, 0x05 },
+	{ 0x3814, 0x11 },
+	{ 0x3815, 0x11 },
+	{ 0x3820, 0x40 },
+	{ 0x3821, 0x00 },
+	{ 0x382f, 0x0e },
+	{ 0x3832, 0x00 },
+	{ 0x3833, 0x05 },
+	{ 0x3834, 0x00 },
+	{ 0x3835, 0x0c },
+	{ 0x3837, 0x00 },
+	{ 0x3b80, 0x00 },
+	{ 0x3b81, 0xa5 },
+	{ 0x3b82, 0x10 },
+	{ 0x3b83, 0x00 },
+	{ 0x3b84, 0x08 },
+	{ 0x3b85, 0x00 },
+	{ 0x3b86, 0x01 },
+	{ 0x3b87, 0x00 },
+	{ 0x3b88, 0x00 },
+	{ 0x3b89, 0x00 },
+	{ 0x3b8a, 0x00 },
+	{ 0x3b8b, 0x05 },
+	{ 0x3b8c, 0x00 },
+	{ 0x3b8d, 0x00 },
+	{ 0x3b8e, 0x00 },
+	{ 0x3b8f, 0x1a },
+	{ 0x3b94, 0x05 },
+	{ 0x3b95, 0xf2 },
+	{ 0x3b96, 0x40 },
+	{ 0x3c00, 0x89 },
+	{ 0x3c01, 0x63 },
+	{ 0x3c02, 0x01 },
+	{ 0x3c03, 0x00 },
+	{ 0x3c04, 0x00 },
+	{ 0x3c05, 0x03 },
+	{ 0x3c06, 0x00 },
+	{ 0x3c07, 0x06 },
+	{ 0x3c0c, 0x01 },
+	{ 0x3c0d, 0xd0 },
+	{ 0x3c0e, 0x02 },
+	{ 0x3c0f, 0x0a },
+	{ 0x4001, 0x42 },
+	{ 0x4004, 0x04 },
+	{ 0x4005, 0x00 },
+	{ 0x404e, 0x01 },
+	{ 0x4300, 0xff },
+	{ 0x4301, 0x00 },
+	{ 0x4315, 0x00 },
+	{ 0x4501, 0x48 },
+	{ 0x4600, 0x00 },
+	{ 0x4601, 0x4e },
+	{ 0x4801, 0x0f },
+	{ 0x4806, 0x0f },
+	{ 0x4819, 0xaa },
+	{ 0x4823, 0x3e },
+	{ 0x4837, 0x19 },
+	{ 0x4a0d, 0x00 },
+	{ 0x4a47, 0x7f },
+	{ 0x4a49, 0xf0 },
+	{ 0x4a4b, 0x30 },
+	{ 0x5000, 0x85 },
+	{ 0x5001, 0x80 },
+};
+
+static const s64 link_freq[] = {
+	240000000,
+};
+
+static const struct ov7251_mode_info ov7251_mode_info_data[] = {
+	{
+		.width = 640,
+		.height = 480,
+		.data = ov7251_setting_vga_30fps,
+		.data_size = ARRAY_SIZE(ov7251_setting_vga_30fps),
+		.pixel_clock = 48000000,
+		.link_freq = 0, /* an index in link_freq[] */
+		.exposure_max = 1704,
+		.exposure_def = 504,
+		.timeperframe = {
+			.numerator = 100,
+			.denominator = 3000
+		}
+	},
+	{
+		.width = 640,
+		.height = 480,
+		.data = ov7251_setting_vga_60fps,
+		.data_size = ARRAY_SIZE(ov7251_setting_vga_60fps),
+		.pixel_clock = 48000000,
+		.link_freq = 0, /* an index in link_freq[] */
+		.exposure_max = 840,
+		.exposure_def = 504,
+		.timeperframe = {
+			.numerator = 100,
+			.denominator = 6014
+		}
+	},
+	{
+		.width = 640,
+		.height = 480,
+		.data = ov7251_setting_vga_90fps,
+		.data_size = ARRAY_SIZE(ov7251_setting_vga_90fps),
+		.pixel_clock = 48000000,
+		.link_freq = 0, /* an index in link_freq[] */
+		.exposure_max = 552,
+		.exposure_def = 504,
+		.timeperframe = {
+			.numerator = 100,
+			.denominator = 9043
+		}
+	},
+};
+
+static int ov7251_regulators_enable(struct ov7251 *ov7251)
+{
+	int ret;
+
+	ret = regulator_enable(ov7251->io_regulator);
+	if (ret < 0) {
+		dev_err(ov7251->dev, "set io voltage failed\n");
+		return ret;
+	}
+
+	ret = regulator_enable(ov7251->analog_regulator);
+	if (ret) {
+		dev_err(ov7251->dev, "set analog voltage failed\n");
+		goto err_disable_io;
+	}
+
+	ret = regulator_enable(ov7251->core_regulator);
+	if (ret) {
+		dev_err(ov7251->dev, "set core voltage failed\n");
+		goto err_disable_analog;
+	}
+
+	return 0;
+
+err_disable_analog:
+	regulator_disable(ov7251->analog_regulator);
+err_disable_io:
+	regulator_disable(ov7251->io_regulator);
+
+	return ret;
+}
+
+static void ov7251_regulators_disable(struct ov7251 *ov7251)
+{
+	int ret;
+
+	ret = regulator_disable(ov7251->core_regulator);
+	if (ret < 0)
+		dev_err(ov7251->dev, "core regulator disable failed\n");
+
+	ret = regulator_disable(ov7251->analog_regulator);
+	if (ret < 0)
+		dev_err(ov7251->dev, "analog regulator disable failed\n");
+
+	ret = regulator_disable(ov7251->io_regulator);
+	if (ret < 0)
+		dev_err(ov7251->dev, "io regulator disable failed\n");
+}
+
+static int ov7251_write_reg(struct ov7251 *ov7251, u16 reg, u8 val)
+{
+	u8 regbuf[3];
+	int ret;
+
+	regbuf[0] = reg >> 8;
+	regbuf[1] = reg & 0xff;
+	regbuf[2] = val;
+
+	ret = i2c_master_send(ov7251->i2c_client, regbuf, 3);
+	if (ret < 0) {
+		dev_err(ov7251->dev, "%s: write reg error %d: reg=%x, val=%x\n",
+			__func__, ret, reg, val);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int ov7251_read_reg(struct ov7251 *ov7251, u16 reg, u8 *val)
+{
+	u8 regbuf[2];
+	int ret;
+
+	regbuf[0] = reg >> 8;
+	regbuf[1] = reg & 0xff;
+
+	ret = i2c_master_send(ov7251->i2c_client, regbuf, 2);
+	if (ret < 0) {
+		dev_err(ov7251->dev, "%s: write reg error %d: reg=%x\n",
+			__func__, ret, reg);
+		return ret;
+	}
+
+	ret = i2c_master_recv(ov7251->i2c_client, val, 1);
+	if (ret < 0) {
+		dev_err(ov7251->dev, "%s: read reg error %d: reg=%x\n",
+			__func__, ret, reg);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int ov7251_set_exposure(struct ov7251 *ov7251, s32 exposure)
+{
+	int ret;
+
+	ret = ov7251_write_reg(ov7251, OV7251_AEC_EXPO_0,
+			       (exposure & 0xf000) >> 12);
+	if (ret < 0)
+		return ret;
+
+	ret = ov7251_write_reg(ov7251, OV7251_AEC_EXPO_1,
+			       (exposure & 0x0ff0) >> 4);
+	if (ret < 0)
+		return ret;
+
+	return ov7251_write_reg(ov7251, OV7251_AEC_EXPO_2,
+				(exposure & 0x000f) << 4);
+}
+
+static int ov7251_set_gain(struct ov7251 *ov7251, s32 gain)
+{
+	int ret;
+
+	ret = ov7251_write_reg(ov7251, OV7251_AEC_AGC_ADJ_0,
+			       (gain & 0x0300) >> 8);
+	if (ret < 0)
+		return ret;
+
+	return ov7251_write_reg(ov7251, OV7251_AEC_AGC_ADJ_1, gain & 0xff);
+}
+
+static int ov7251_set_register_array(struct ov7251 *ov7251,
+				     const struct reg_value *settings,
+				     unsigned int num_settings)
+{
+	unsigned int i;
+	int ret;
+
+	for (i = 0; i < num_settings; ++i, ++settings) {
+		ret = ov7251_write_reg(ov7251, settings->reg, settings->val);
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int ov7251_set_power_on(struct ov7251 *ov7251)
+{
+	int ret;
+
+	ret = ov7251_regulators_enable(ov7251);
+	if (ret < 0)
+		return ret;
+
+	ret = clk_prepare_enable(ov7251->xclk);
+	if (ret < 0) {
+		dev_err(ov7251->dev, "clk prepare enable failed\n");
+		ov7251_regulators_disable(ov7251);
+		return ret;
+	}
+
+	gpiod_set_value_cansleep(ov7251->enable_gpio, 1);
+
+	usleep_range(3000, 4000); /* 65536 / 24MHz = 2.73ms */
+
+	return 0;
+}
+
+static void ov7251_set_power_off(struct ov7251 *ov7251)
+{
+	clk_disable_unprepare(ov7251->xclk);
+	gpiod_set_value_cansleep(ov7251->enable_gpio, 0);
+	ov7251_regulators_disable(ov7251);
+}
+
+static int ov7251_s_power(struct v4l2_subdev *sd, int on)
+{
+	struct ov7251 *ov7251 = to_ov7251(sd);
+	int ret = 0;
+
+	mutex_lock(&ov7251->power_lock);
+
+	/*
+	 * If the power state is modified from 0 to 1 or from 1 to 0,
+	 * update the power state.
+	 */
+	if (ov7251->power_on == !on) {
+		if (on) {
+			ret = ov7251_set_power_on(ov7251);
+			if (ret < 0)
+				goto exit;
+
+			ret = ov7251_set_register_array(ov7251,
+					ov7251_global_init_setting,
+					ARRAY_SIZE(ov7251_global_init_setting));
+			if (ret < 0) {
+				dev_err(ov7251->dev,
+					"could not set init registers\n");
+				ov7251_set_power_off(ov7251);
+				goto exit;
+			}
+
+			ov7251->power_on = true;
+		} else {
+			ov7251_set_power_off(ov7251);
+			ov7251->power_on = false;
+		}
+	}
+
+exit:
+	mutex_unlock(&ov7251->power_lock);
+
+	return ret;
+}
+
+static int ov7251_set_hflip(struct ov7251 *ov7251, s32 value)
+{
+	u8 val = ov7251->timing_format2;
+	int ret;
+
+	if (value)
+		val |= OV7251_TIMING_FORMAT2_MIRROR;
+	else
+		val &= ~OV7251_TIMING_FORMAT2_MIRROR;
+
+	ret = ov7251_write_reg(ov7251, OV7251_TIMING_FORMAT2, val);
+	if (!ret)
+		ov7251->timing_format2 = val;
+
+	return ret;
+}
+
+static int ov7251_set_vflip(struct ov7251 *ov7251, s32 value)
+{
+	u8 val = ov7251->timing_format1;
+	int ret;
+
+	if (value)
+		val |= OV7251_TIMING_FORMAT1_VFLIP;
+	else
+		val &= ~OV7251_TIMING_FORMAT1_VFLIP;
+
+	ret = ov7251_write_reg(ov7251, OV7251_TIMING_FORMAT1, val);
+	if (!ret)
+		ov7251->timing_format1 = val;
+
+	return ret;
+}
+
+static int ov7251_set_test_pattern(struct ov7251 *ov7251, s32 value)
+{
+	u8 val = ov7251->pre_isp_00;
+	int ret;
+
+	if (value)
+		val |= OV7251_PRE_ISP_00_TEST_PATTERN;
+	else
+		val &= ~OV7251_PRE_ISP_00_TEST_PATTERN;
+
+	ret = ov7251_write_reg(ov7251, OV7251_PRE_ISP_00, val);
+	if (!ret)
+		ov7251->pre_isp_00 = val;
+
+	return ret;
+}
+
+static const char * const ov7251_test_pattern_menu[] = {
+	"Disabled",
+	"Vertical Pattern Bars",
+};
+
+static int ov7251_s_ctrl(struct v4l2_ctrl *ctrl)
+{
+	struct ov7251 *ov7251 = container_of(ctrl->handler,
+					     struct ov7251, ctrls);
+	int ret;
+
+	mutex_lock(&ov7251->power_lock);
+	if (!ov7251->power_on) {
+		mutex_unlock(&ov7251->power_lock);
+		return 0;
+	}
+
+	switch (ctrl->id) {
+	case V4L2_CID_EXPOSURE:
+		ret = ov7251_set_exposure(ov7251, ctrl->val);
+		break;
+	case V4L2_CID_GAIN:
+		ret = ov7251_set_gain(ov7251, ctrl->val);
+		break;
+	case V4L2_CID_TEST_PATTERN:
+		ret = ov7251_set_test_pattern(ov7251, ctrl->val);
+		break;
+	case V4L2_CID_HFLIP:
+		ret = ov7251_set_hflip(ov7251, ctrl->val);
+		break;
+	case V4L2_CID_VFLIP:
+		ret = ov7251_set_vflip(ov7251, ctrl->val);
+		break;
+	default:
+		ret = -EINVAL;
+		break;
+	}
+
+	mutex_unlock(&ov7251->power_lock);
+
+	return ret;
+}
+
+static const struct v4l2_ctrl_ops ov7251_ctrl_ops = {
+	.s_ctrl = ov7251_s_ctrl,
+};
+
+static int ov7251_enum_mbus_code(struct v4l2_subdev *sd,
+				 struct v4l2_subdev_pad_config *cfg,
+				 struct v4l2_subdev_mbus_code_enum *code)
+{
+	if (code->index > 0)
+		return -EINVAL;
+
+	code->code = MEDIA_BUS_FMT_SBGGR10_1X10;
+
+	return 0;
+}
+
+static int ov7251_enum_frame_size(struct v4l2_subdev *subdev,
+				  struct v4l2_subdev_pad_config *cfg,
+				  struct v4l2_subdev_frame_size_enum *fse)
+{
+	if (fse->code != MEDIA_BUS_FMT_SBGGR10_1X10)
+		return -EINVAL;
+
+	if (fse->index >= ARRAY_SIZE(ov7251_mode_info_data))
+		return -EINVAL;
+
+	fse->min_width = ov7251_mode_info_data[fse->index].width;
+	fse->max_width = ov7251_mode_info_data[fse->index].width;
+	fse->min_height = ov7251_mode_info_data[fse->index].height;
+	fse->max_height = ov7251_mode_info_data[fse->index].height;
+
+	return 0;
+}
+
+static int ov7251_enum_frame_ival(struct v4l2_subdev *subdev,
+				  struct v4l2_subdev_pad_config *cfg,
+				  struct v4l2_subdev_frame_interval_enum *fie)
+{
+	int index = fie->index;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(ov7251_mode_info_data); i++) {
+		if (fie->width != ov7251_mode_info_data[i].width ||
+		    fie->height != ov7251_mode_info_data[i].height)
+			continue;
+
+		if (index-- == 0) {
+			fie->interval = ov7251_mode_info_data[i].timeperframe;
+			return 0;
+		}
+	}
+
+	return -EINVAL;
+}
+
+static struct v4l2_mbus_framefmt *
+__ov7251_get_pad_format(struct ov7251 *ov7251,
+			struct v4l2_subdev_pad_config *cfg,
+			unsigned int pad,
+			enum v4l2_subdev_format_whence which)
+{
+	switch (which) {
+	case V4L2_SUBDEV_FORMAT_TRY:
+		return v4l2_subdev_get_try_format(&ov7251->sd, cfg, pad);
+	case V4L2_SUBDEV_FORMAT_ACTIVE:
+		return &ov7251->fmt;
+	default:
+		return NULL;
+	}
+}
+
+static int ov7251_get_format(struct v4l2_subdev *sd,
+			     struct v4l2_subdev_pad_config *cfg,
+			     struct v4l2_subdev_format *format)
+{
+	struct ov7251 *ov7251 = to_ov7251(sd);
+
+	format->format = *__ov7251_get_pad_format(ov7251, cfg, format->pad,
+						  format->which);
+	return 0;
+}
+
+static struct v4l2_rect *
+__ov7251_get_pad_crop(struct ov7251 *ov7251, struct v4l2_subdev_pad_config *cfg,
+		      unsigned int pad, enum v4l2_subdev_format_whence which)
+{
+	switch (which) {
+	case V4L2_SUBDEV_FORMAT_TRY:
+		return v4l2_subdev_get_try_crop(&ov7251->sd, cfg, pad);
+	case V4L2_SUBDEV_FORMAT_ACTIVE:
+		return &ov7251->crop;
+	default:
+		return NULL;
+	}
+}
+
+#define TIMEPERFRAME_AVG_FPS(t)						\
+	(((t).denominator + ((t).numerator >> 1)) / (t).numerator)
+
+static const struct ov7251_mode_info *
+ov7251_find_mode_by_ival(struct ov7251 *ov7251, struct v4l2_fract *timeperframe)
+{
+	const struct ov7251_mode_info *mode = ov7251->current_mode;
+	int fps_req = TIMEPERFRAME_AVG_FPS(*timeperframe);
+	unsigned int max_dist_match = (unsigned int) -1;
+	int i, n = 0;
+
+	for (i = 0; i < ARRAY_SIZE(ov7251_mode_info_data); i++) {
+		unsigned int dist;
+		int fps_tmp;
+
+		if (mode->width != ov7251_mode_info_data[i].width ||
+		    mode->height != ov7251_mode_info_data[i].height)
+			continue;
+
+		fps_tmp = TIMEPERFRAME_AVG_FPS(
+					ov7251_mode_info_data[i].timeperframe);
+
+		dist = abs(fps_req - fps_tmp);
+
+		if (dist < max_dist_match) {
+			n = i;
+			max_dist_match = dist;
+		}
+	}
+
+	return &ov7251_mode_info_data[n];
+}
+
+static int ov7251_set_format(struct v4l2_subdev *sd,
+			     struct v4l2_subdev_pad_config *cfg,
+			     struct v4l2_subdev_format *format)
+{
+	struct ov7251 *ov7251 = to_ov7251(sd);
+	struct v4l2_mbus_framefmt *__format;
+	struct v4l2_rect *__crop;
+	const struct ov7251_mode_info *new_mode;
+	int ret;
+
+	__crop = __ov7251_get_pad_crop(ov7251, cfg, format->pad,
+			format->which);
+
+	new_mode = v4l2_find_nearest_size(ov7251_mode_info_data,
+			       width, height,
+			       format->format.width, format->format.height);
+
+	__crop->width = new_mode->width;
+	__crop->height = new_mode->height;
+
+	if (format->which == V4L2_SUBDEV_FORMAT_ACTIVE) {
+		ret = v4l2_ctrl_s_ctrl_int64(ov7251->pixel_clock,
+					     new_mode->pixel_clock);
+		if (ret < 0)
+			return ret;
+
+		ret = v4l2_ctrl_s_ctrl(ov7251->link_freq,
+				       new_mode->link_freq);
+		if (ret < 0)
+			return ret;
+
+		ret = v4l2_ctrl_modify_range(ov7251->exposure,
+					     1, new_mode->exposure_max,
+					     1, new_mode->exposure_def);
+		if (ret < 0)
+			return ret;
+
+		ret = v4l2_ctrl_s_ctrl(ov7251->exposure,
+				       new_mode->exposure_def);
+		if (ret < 0)
+			return ret;
+
+
+		ret = v4l2_ctrl_s_ctrl(ov7251->gain, 16);
+		if (ret < 0)
+			return ret;
+
+		ov7251->current_mode = new_mode;
+	}
+
+	__format = __ov7251_get_pad_format(ov7251, cfg, format->pad,
+			format->which);
+	__format->width = __crop->width;
+	__format->height = __crop->height;
+	__format->code = MEDIA_BUS_FMT_SBGGR10_1X10;
+	__format->field = V4L2_FIELD_NONE;
+	__format->colorspace = V4L2_COLORSPACE_SRGB;
+	__format->ycbcr_enc = V4L2_MAP_YCBCR_ENC_DEFAULT(__format->colorspace);
+	__format->quantization = V4L2_MAP_QUANTIZATION_DEFAULT(true,
+				__format->colorspace, __format->ycbcr_enc);
+	__format->xfer_func = V4L2_MAP_XFER_FUNC_DEFAULT(__format->colorspace);
+
+	format->format = *__format;
+
+	return 0;
+}
+
+static int ov7251_entity_init_cfg(struct v4l2_subdev *subdev,
+				  struct v4l2_subdev_pad_config *cfg)
+{
+	struct v4l2_subdev_format fmt = { 0 };
+
+	fmt.which = cfg ? V4L2_SUBDEV_FORMAT_TRY : V4L2_SUBDEV_FORMAT_ACTIVE;
+	fmt.format.width = 640;
+	fmt.format.height = 480;
+
+	ov7251_set_format(subdev, cfg, &fmt);
+
+	return 0;
+}
+
+static int ov7251_get_selection(struct v4l2_subdev *sd,
+			   struct v4l2_subdev_pad_config *cfg,
+			   struct v4l2_subdev_selection *sel)
+{
+	struct ov7251 *ov7251 = to_ov7251(sd);
+
+	if (sel->target != V4L2_SEL_TGT_CROP)
+		return -EINVAL;
+
+	sel->r = *__ov7251_get_pad_crop(ov7251, cfg, sel->pad,
+					sel->which);
+	return 0;
+}
+
+static int ov7251_s_stream(struct v4l2_subdev *subdev, int enable)
+{
+	struct ov7251 *ov7251 = to_ov7251(subdev);
+	int ret;
+
+	if (enable) {
+		ret = ov7251_set_register_array(ov7251,
+					ov7251->current_mode->data,
+					ov7251->current_mode->data_size);
+		if (ret < 0) {
+			dev_err(ov7251->dev, "could not set mode %dx%d\n",
+				ov7251->current_mode->width,
+				ov7251->current_mode->height);
+			return ret;
+		}
+		ret = v4l2_ctrl_handler_setup(&ov7251->ctrls);
+		if (ret < 0) {
+			dev_err(ov7251->dev, "could not sync v4l2 controls\n");
+			return ret;
+		}
+		ret = ov7251_write_reg(ov7251, OV7251_SC_MODE_SELECT,
+				       OV7251_SC_MODE_SELECT_STREAMING);
+		if (ret < 0)
+			return ret;
+	} else {
+		ret = ov7251_write_reg(ov7251, OV7251_SC_MODE_SELECT,
+				       OV7251_SC_MODE_SELECT_SW_STANDBY);
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int ov7251_get_frame_interval(struct v4l2_subdev *subdev,
+				     struct v4l2_subdev_frame_interval *fi)
+{
+	struct ov7251 *ov7251 = to_ov7251(subdev);
+
+	fi->interval = ov7251->current_mode->timeperframe;
+
+	return 0;
+}
+
+static int ov7251_set_frame_interval(struct v4l2_subdev *subdev,
+				     struct v4l2_subdev_frame_interval *fi)
+{
+	struct ov7251 *ov7251 = to_ov7251(subdev);
+	const struct ov7251_mode_info *new_mode;
+
+	new_mode = ov7251_find_mode_by_ival(ov7251, &fi->interval);
+
+	if (new_mode != ov7251->current_mode) {
+		int ret;
+
+		ret = v4l2_ctrl_s_ctrl_int64(ov7251->pixel_clock,
+					     new_mode->pixel_clock);
+		if (ret < 0)
+			return ret;
+
+		ret = v4l2_ctrl_s_ctrl(ov7251->link_freq,
+				       new_mode->link_freq);
+		if (ret < 0)
+			return ret;
+
+		ret = v4l2_ctrl_modify_range(ov7251->exposure,
+					     1, new_mode->exposure_max,
+					     1, new_mode->exposure_def);
+		if (ret < 0)
+			return ret;
+
+		ret = v4l2_ctrl_s_ctrl(ov7251->exposure,
+				       new_mode->exposure_def);
+		if (ret < 0)
+			return ret;
+
+		ret = v4l2_ctrl_s_ctrl(ov7251->gain, 16);
+		if (ret < 0)
+			return ret;
+
+		ov7251->current_mode = new_mode;
+	}
+
+	fi->interval = ov7251->current_mode->timeperframe;
+
+	return 0;
+}
+
+static const struct v4l2_subdev_core_ops ov7251_core_ops = {
+	.s_power = ov7251_s_power,
+};
+
+static const struct v4l2_subdev_video_ops ov7251_video_ops = {
+	.s_stream = ov7251_s_stream,
+	.g_frame_interval = ov7251_get_frame_interval,
+	.s_frame_interval = ov7251_set_frame_interval,
+};
+
+static const struct v4l2_subdev_pad_ops ov7251_subdev_pad_ops = {
+	.init_cfg = ov7251_entity_init_cfg,
+	.enum_mbus_code = ov7251_enum_mbus_code,
+	.enum_frame_size = ov7251_enum_frame_size,
+	.enum_frame_interval = ov7251_enum_frame_ival,
+	.get_fmt = ov7251_get_format,
+	.set_fmt = ov7251_set_format,
+	.get_selection = ov7251_get_selection,
+};
+
+static const struct v4l2_subdev_ops ov7251_subdev_ops = {
+	.core = &ov7251_core_ops,
+	.video = &ov7251_video_ops,
+	.pad = &ov7251_subdev_pad_ops,
+};
+
+static int ov7251_probe(struct i2c_client *client,
+			const struct i2c_device_id *id)
+{
+	struct device *dev = &client->dev;
+	struct fwnode_handle *endpoint;
+	struct ov7251 *ov7251;
+	u8 chip_id_high, chip_id_low, chip_rev;
+	u32 xclk_freq;
+	int ret;
+
+	ov7251 = devm_kzalloc(dev, sizeof(struct ov7251), GFP_KERNEL);
+	if (!ov7251)
+		return -ENOMEM;
+
+	ov7251->i2c_client = client;
+	ov7251->dev = dev;
+
+	endpoint = fwnode_graph_get_next_endpoint(dev_fwnode(dev), NULL);
+	if (!endpoint) {
+		dev_err(dev, "endpoint node not found\n");
+		return -EINVAL;
+	}
+
+	ret = v4l2_fwnode_endpoint_parse(endpoint, &ov7251->ep);
+	fwnode_handle_put(endpoint);
+	if (ret < 0) {
+		dev_err(dev, "parsing endpoint node failed\n");
+		return ret;
+	}
+
+	if (ov7251->ep.bus_type != V4L2_MBUS_CSI2) {
+		dev_err(dev, "invalid bus type (%u), must be CSI2 (%u)\n",
+			ov7251->ep.bus_type, V4L2_MBUS_CSI2);
+		return -EINVAL;
+	}
+
+	/* get system clock (xclk) */
+	ov7251->xclk = devm_clk_get(dev, "xclk");
+	if (IS_ERR(ov7251->xclk)) {
+		dev_err(dev, "could not get xclk");
+		return PTR_ERR(ov7251->xclk);
+	}
+
+	ret = of_property_read_u32(dev->of_node, "clock-frequency", &xclk_freq);
+	if (ret) {
+		dev_err(dev, "could not get xclk frequency\n");
+		return ret;
+	}
+
+	/* external clock must be 24MHz, allow 1% tolerance */
+	if (xclk_freq < 23760000 || xclk_freq > 24240000) {
+		dev_err(dev, "external clock frequency %u is not supported\n",
+			xclk_freq);
+		return -EINVAL;
+	}
+
+	ret = clk_set_rate(ov7251->xclk, xclk_freq);
+	if (ret) {
+		dev_err(dev, "could not set xclk frequency\n");
+		return ret;
+	}
+
+	ov7251->io_regulator = devm_regulator_get(dev, "vdddo");
+	if (IS_ERR(ov7251->io_regulator)) {
+		dev_err(dev, "cannot get io regulator\n");
+		return PTR_ERR(ov7251->io_regulator);
+	}
+
+	ret = regulator_set_voltage(ov7251->io_regulator,
+				    OV7251_VOLTAGE_DIGITAL_IO,
+				    OV7251_VOLTAGE_DIGITAL_IO);
+	if (ret < 0) {
+		dev_err(dev, "cannot set io voltage\n");
+		return ret;
+	}
+
+	ov7251->core_regulator = devm_regulator_get(dev, "vddd");
+	if (IS_ERR(ov7251->core_regulator)) {
+		dev_err(dev, "cannot get core regulator\n");
+		return PTR_ERR(ov7251->core_regulator);
+	}
+
+	ret = regulator_set_voltage(ov7251->core_regulator,
+				    OV7251_VOLTAGE_DIGITAL_CORE,
+				    OV7251_VOLTAGE_DIGITAL_CORE);
+	if (ret < 0) {
+		dev_err(dev, "cannot set core voltage\n");
+		return ret;
+	}
+
+	ov7251->analog_regulator = devm_regulator_get(dev, "vdda");
+	if (IS_ERR(ov7251->analog_regulator)) {
+		dev_err(dev, "cannot get analog regulator\n");
+		return PTR_ERR(ov7251->analog_regulator);
+	}
+
+	ret = regulator_set_voltage(ov7251->analog_regulator,
+				    OV7251_VOLTAGE_ANALOG,
+				    OV7251_VOLTAGE_ANALOG);
+	if (ret < 0) {
+		dev_err(dev, "cannot set analog voltage\n");
+		return ret;
+	}
+
+	ov7251->enable_gpio = devm_gpiod_get(dev, "enable", GPIOD_OUT_HIGH);
+	if (IS_ERR(ov7251->enable_gpio)) {
+		dev_err(dev, "cannot get enable gpio\n");
+		return PTR_ERR(ov7251->enable_gpio);
+	}
+
+	mutex_init(&ov7251->power_lock);
+
+	v4l2_ctrl_handler_init(&ov7251->ctrls, 7);
+	v4l2_ctrl_new_std(&ov7251->ctrls, &ov7251_ctrl_ops,
+			  V4L2_CID_HFLIP, 0, 1, 1, 0);
+	v4l2_ctrl_new_std(&ov7251->ctrls, &ov7251_ctrl_ops,
+			  V4L2_CID_VFLIP, 0, 1, 1, 0);
+	ov7251->exposure = v4l2_ctrl_new_std(&ov7251->ctrls, &ov7251_ctrl_ops,
+					     V4L2_CID_EXPOSURE, 1, 32, 1, 32);
+	ov7251->gain = v4l2_ctrl_new_std(&ov7251->ctrls, &ov7251_ctrl_ops,
+					 V4L2_CID_GAIN, 16, 1023, 1, 16);
+	v4l2_ctrl_new_std_menu_items(&ov7251->ctrls, &ov7251_ctrl_ops,
+				     V4L2_CID_TEST_PATTERN,
+				     ARRAY_SIZE(ov7251_test_pattern_menu) - 1,
+				     0, 0, ov7251_test_pattern_menu);
+	ov7251->pixel_clock = v4l2_ctrl_new_std(&ov7251->ctrls,
+						&ov7251_ctrl_ops,
+						V4L2_CID_PIXEL_RATE,
+						1, INT_MAX, 1, 1);
+	ov7251->link_freq = v4l2_ctrl_new_int_menu(&ov7251->ctrls,
+						   &ov7251_ctrl_ops,
+						   V4L2_CID_LINK_FREQ,
+						   ARRAY_SIZE(link_freq) - 1,
+						   0, link_freq);
+	if (ov7251->link_freq)
+		ov7251->link_freq->flags |= V4L2_CTRL_FLAG_READ_ONLY;
+
+	ov7251->sd.ctrl_handler = &ov7251->ctrls;
+
+	if (ov7251->ctrls.error) {
+		dev_err(dev, "%s: control initialization error %d\n",
+		       __func__, ov7251->ctrls.error);
+		ret = ov7251->ctrls.error;
+		goto free_ctrl;
+	}
+
+	v4l2_i2c_subdev_init(&ov7251->sd, client, &ov7251_subdev_ops);
+	ov7251->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
+	ov7251->pad.flags = MEDIA_PAD_FL_SOURCE;
+	ov7251->sd.dev = &client->dev;
+	ov7251->sd.entity.function = MEDIA_ENT_F_CAM_SENSOR;
+
+	ret = media_entity_pads_init(&ov7251->sd.entity, 1, &ov7251->pad);
+	if (ret < 0) {
+		dev_err(dev, "could not register media entity\n");
+		goto free_ctrl;
+	}
+
+	ret = ov7251_s_power(&ov7251->sd, true);
+	if (ret < 0) {
+		dev_err(dev, "could not power up OV7251\n");
+		goto free_entity;
+	}
+
+	ret = ov7251_read_reg(ov7251, OV7251_CHIP_ID_HIGH, &chip_id_high);
+	if (ret < 0 || chip_id_high != OV7251_CHIP_ID_HIGH_BYTE) {
+		dev_err(dev, "could not read ID high\n");
+		ret = -ENODEV;
+		goto power_down;
+	}
+	ret = ov7251_read_reg(ov7251, OV7251_CHIP_ID_LOW, &chip_id_low);
+	if (ret < 0 || chip_id_low != OV7251_CHIP_ID_LOW_BYTE) {
+		dev_err(dev, "could not read ID low\n");
+		ret = -ENODEV;
+		goto power_down;
+	}
+
+	ret = ov7251_read_reg(ov7251, OV7251_SC_GP_IO_IN1, &chip_rev);
+	if (ret < 0) {
+		dev_err(dev, "could not read revision\n");
+		ret = -ENODEV;
+		goto power_down;
+	}
+	chip_rev >>= 4;
+
+	dev_info(dev, "OV7251 revision %x (%s) detected at address 0x%02x\n",
+		 chip_rev,
+		 chip_rev == 0x4 ? "1A / 1B" :
+		 chip_rev == 0x5 ? "1C / 1D" :
+		 chip_rev == 0x6 ? "1E" :
+		 chip_rev == 0x7 ? "1F" : "unknown",
+		 client->addr);
+
+	ret = ov7251_read_reg(ov7251, OV7251_PRE_ISP_00,
+			      &ov7251->pre_isp_00);
+	if (ret < 0) {
+		dev_err(dev, "could not read test pattern value\n");
+		ret = -ENODEV;
+		goto power_down;
+	}
+
+	ret = ov7251_read_reg(ov7251, OV7251_TIMING_FORMAT1,
+			      &ov7251->timing_format1);
+	if (ret < 0) {
+		dev_err(dev, "could not read vflip value\n");
+		ret = -ENODEV;
+		goto power_down;
+	}
+
+	ret = ov7251_read_reg(ov7251, OV7251_TIMING_FORMAT2,
+			      &ov7251->timing_format2);
+	if (ret < 0) {
+		dev_err(dev, "could not read hflip value\n");
+		ret = -ENODEV;
+		goto power_down;
+	}
+
+	ov7251_s_power(&ov7251->sd, false);
+
+	ret = v4l2_async_register_subdev(&ov7251->sd);
+	if (ret < 0) {
+		dev_err(dev, "could not register v4l2 device\n");
+		goto free_entity;
+	}
+
+	ov7251_entity_init_cfg(&ov7251->sd, NULL);
+
+	return 0;
+
+power_down:
+	ov7251_s_power(&ov7251->sd, false);
+free_entity:
+	media_entity_cleanup(&ov7251->sd.entity);
+free_ctrl:
+	v4l2_ctrl_handler_free(&ov7251->ctrls);
+	mutex_destroy(&ov7251->power_lock);
+
+	return ret;
+}
+
+static int ov7251_remove(struct i2c_client *client)
+{
+	struct v4l2_subdev *sd = i2c_get_clientdata(client);
+	struct ov7251 *ov7251 = to_ov7251(sd);
+
+	v4l2_async_unregister_subdev(&ov7251->sd);
+	media_entity_cleanup(&ov7251->sd.entity);
+	v4l2_ctrl_handler_free(&ov7251->ctrls);
+	mutex_destroy(&ov7251->power_lock);
+
+	return 0;
+}
+
+static const struct i2c_device_id ov7251_id[] = {
+	{ "ov7251", 0 },
+	{}
+};
+MODULE_DEVICE_TABLE(i2c, ov7251_id);
+
+static const struct of_device_id ov7251_of_match[] = {
+	{ .compatible = "ovti,ov7251" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, ov7251_of_match);
+
+static struct i2c_driver ov7251_i2c_driver = {
+	.driver = {
+		.of_match_table = of_match_ptr(ov7251_of_match),
+		.name  = "ov7251",
+	},
+	.probe  = ov7251_probe,
+	.remove = ov7251_remove,
+	.id_table = ov7251_id,
+};
+
+module_i2c_driver(ov7251_i2c_driver);
+
+MODULE_DESCRIPTION("Omnivision OV7251 Camera Driver");
+MODULE_AUTHOR("Todor Tomov <todor.tomov@linaro.org>");
+MODULE_LICENSE("GPL v2");