diff mbox

[RFC] introduce gspca-stk1135: Syntek STK1135 driver

Message ID 201308110010.56508.linux@rainbow-software.org (mailing list archive)
State New, archived
Headers show

Commit Message

Ondrej Zary Aug. 10, 2013, 10:10 p.m. UTC
Hello,
this is a new gspca driver for Syntek STK1135 webcams. The code is completely
new, but register values are based on Syntekdriver (stk11xx) by Nicolas VIVIEN
(http://syntekdriver.sourceforge.net).

Only one webcam type is supported now - vendor 0x174f, device 0x6a31.
It's Asus F5RL laptop flippable webcam with MT9M112.

The camera works better than in Windows - initializes much faster and
provides more resolutions (the sensor can do almost any resolution - just
add it to the stk1135_modes[] - could this feature be somehow used by
applications to avoid SW scaling?).

Autoflip works too - when the camera is flipped around, the image is flipped
automatically.

Signed-off-by: Ondrej Zary <linux@rainbow-software.org>

Comments

Hans de Goede Aug. 11, 2013, 9:26 a.m. UTC | #1
Hi,

On 08/11/2013 12:10 AM, Ondrej Zary wrote:
> Hello,
> this is a new gspca driver for Syntek STK1135 webcams. The code is completely
> new, but register values are based on Syntekdriver (stk11xx) by Nicolas VIVIEN
> (http://syntekdriver.sourceforge.net).
>
> Only one webcam type is supported now - vendor 0x174f, device 0x6a31.
> It's Asus F5RL laptop flippable webcam with MT9M112.
>
> The camera works better than in Windows - initializes much faster and
> provides more resolutions

You've certainly done this quickly, many thanks for working on this!

Looks good. Any reason why this is RFC, iow any reason why I should not add
this to my tree and include it in my next pullreq to Mauro ?

> Autoflip works too - when the camera is flipped around, the image is flipped
> automatically.

Cool, but I've some comments on the implementation:

1) It seems autoflip and manual flip with controls conflict, the manual
setting will be overwritten as soon as the switch is debounced.
I think it would be best to make the manual setting invert (when on) the
setting detected from the switch

2) You make the switch control both hflip and vflip, but the way the flipping
works the sensor is not turned upside down, but rotated over its x-axis, so
you should only set vflip based on the switch if I'm not mistaken. To verify this
take a piece of paper, and write on it with large letters "HELLO" then hold
it in front of the camera. It should read normally on the screen. I believe that
in one of the 2 orientations of the camera it will be mirrored now since you
set hflip while it should not be set

3) Once debounced is over 100, you re-set hflip and vflip every frame, this causes
expensive USB IO, so please cache the current setting and only change it if it
actually needs to change

If you can do a new version with these 3 things fixed I'll happily pull it into
my tree!

Regards,

Hans
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Ondrej Zary Aug. 11, 2013, 4:26 p.m. UTC | #2
On Sunday 11 August 2013 11:26:18 Hans de Goede wrote:
> Hi,
>
> On 08/11/2013 12:10 AM, Ondrej Zary wrote:
> > Hello,
> > this is a new gspca driver for Syntek STK1135 webcams. The code is
> > completely new, but register values are based on Syntekdriver (stk11xx)
> > by Nicolas VIVIEN (http://syntekdriver.sourceforge.net).
> >
> > Only one webcam type is supported now - vendor 0x174f, device 0x6a31.
> > It's Asus F5RL laptop flippable webcam with MT9M112.
> >
> > The camera works better than in Windows - initializes much faster and
> > provides more resolutions
>
> You've certainly done this quickly, many thanks for working on this!
>
> Looks good. Any reason why this is RFC, iow any reason why I should not add
> this to my tree and include it in my next pullreq to Mauro ?
>
> > Autoflip works too - when the camera is flipped around, the image is
> > flipped automatically.
>
> Cool, but I've some comments on the implementation:
>
> 1) It seems autoflip and manual flip with controls conflict, the manual
> setting will be overwritten as soon as the switch is debounced.
> I think it would be best to make the manual setting invert (when on) the
> setting detected from the switch

Yes, that's a problem. Too bad that there's no "autorotate" control in V4L2. 
Inverting seems like a good idea.

> 2) You make the switch control both hflip and vflip, but the way the
> flipping works the sensor is not turned upside down, but rotated over its
> x-axis, so you should only set vflip based on the switch if I'm not
> mistaken. To verify this take a piece of paper, and write on it with large
> letters "HELLO" then hold it in front of the camera. It should read
> normally on the screen. I believe that in one of the 2 orientations of the
> camera it will be mirrored now since you set hflip while it should not be
> set

I thought that too at first - and changed only vflip. Then noticed that the 
image is mirrored when the camera is flipped to the back.

When the sensor is rotated over its x-axis, the "left" side of the sensor will 
be on the right side (when you look from the back of the laptop).

> 3) Once debounced is over 100, you re-set hflip and vflip every frame, this
> causes expensive USB IO, so please cache the current setting and only
> change it if it actually needs to change

When debounce gets over 100, flip_status is inverted (so it matches the 
current state reported by camera). Thus, debounce is not incremented in 
sd_pkt_scan but reset to 0 instead.
Maybe the code could be re-arranged somehow to make this more clear.

> If you can do a new version with these 3 things fixed I'll happily pull it
> into my tree!

Working on it now.
diff mbox

Patch

diff --git a/drivers/media/usb/gspca/Kconfig b/drivers/media/usb/gspca/Kconfig
index 6345f93..4f0c6d5 100644
--- a/drivers/media/usb/gspca/Kconfig
+++ b/drivers/media/usb/gspca/Kconfig
@@ -338,6 +338,15 @@  config USB_GSPCA_STK014
 	  To compile this driver as a module, choose M here: the
 	  module will be called gspca_stk014.
 
+config USB_GSPCA_STK1135
+	tristate "Syntek STK1135 USB Camera Driver"
+	depends on VIDEO_V4L2 && USB_GSPCA
+	help
+	  Say Y here if you want support for cameras based on the STK1135 chip.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called gspca_stk1135.
+
 config USB_GSPCA_STV0680
 	tristate "STV0680 USB Camera Driver"
 	depends on VIDEO_V4L2 && USB_GSPCA
diff --git a/drivers/media/usb/gspca/Makefile b/drivers/media/usb/gspca/Makefile
index c901da0..5855131 100644
--- a/drivers/media/usb/gspca/Makefile
+++ b/drivers/media/usb/gspca/Makefile
@@ -34,6 +34,7 @@  obj-$(CONFIG_USB_GSPCA_SQ905C)   += gspca_sq905c.o
 obj-$(CONFIG_USB_GSPCA_SQ930X)   += gspca_sq930x.o
 obj-$(CONFIG_USB_GSPCA_SUNPLUS)  += gspca_sunplus.o
 obj-$(CONFIG_USB_GSPCA_STK014)   += gspca_stk014.o
+obj-$(CONFIG_USB_GSPCA_STK1135)  += gspca_stk1135.o
 obj-$(CONFIG_USB_GSPCA_STV0680)  += gspca_stv0680.o
 obj-$(CONFIG_USB_GSPCA_T613)     += gspca_t613.o
 obj-$(CONFIG_USB_GSPCA_TOPRO)    += gspca_topro.o
@@ -78,6 +79,7 @@  gspca_sq905-objs    := sq905.o
 gspca_sq905c-objs   := sq905c.o
 gspca_sq930x-objs   := sq930x.o
 gspca_stk014-objs   := stk014.o
+gspca_stk1135-objs  := stk1135.o
 gspca_stv0680-objs  := stv0680.o
 gspca_sunplus-objs  := sunplus.o
 gspca_t613-objs     := t613.o
diff --git a/drivers/media/usb/gspca/stk1135.c b/drivers/media/usb/gspca/stk1135.c
new file mode 100644
index 0000000..0921491
--- /dev/null
+++ b/drivers/media/usb/gspca/stk1135.c
@@ -0,0 +1,671 @@ 
+/*
+ * Syntek STK1135 subdriver
+ *
+ * Copyright (c) 2013 Ondrej Zary
+ *
+ * Based on Syntekdriver (stk11xx) by Nicolas VIVIEN:
+ *   http://syntekdriver.sourceforge.net
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#define MODULE_NAME "stk1135"
+
+#include "gspca.h"
+#include "stk1135.h"
+
+MODULE_AUTHOR("Ondrej Zary");
+MODULE_DESCRIPTION("Syntek STK1135 USB Camera Driver");
+MODULE_LICENSE("GPL");
+
+
+/* specific webcam descriptor */
+struct sd {
+	struct gspca_dev gspca_dev;	/* !! must be the first item */
+
+	u8 pkt_seq;
+	u8 sensor_page;
+
+	bool flip_status;
+	u8 flip_debounce;
+};
+
+static const struct v4l2_pix_format stk1135_modes[] = {
+	{160, 120, V4L2_PIX_FMT_SBGGR8, V4L2_FIELD_NONE,
+		.bytesperline = 160,
+		.sizeimage = 160 * 120,
+		.colorspace = V4L2_COLORSPACE_SRGB},
+	{176, 144, V4L2_PIX_FMT_SBGGR8, V4L2_FIELD_NONE,
+		.bytesperline = 176,
+		.sizeimage = 176 * 144,
+		.colorspace = V4L2_COLORSPACE_SRGB},
+	{320, 240, V4L2_PIX_FMT_SBGGR8, V4L2_FIELD_NONE,
+		.bytesperline = 320,
+		.sizeimage = 320 * 240,
+		.colorspace = V4L2_COLORSPACE_SRGB},
+	{352, 288, V4L2_PIX_FMT_SBGGR8, V4L2_FIELD_NONE,
+		.bytesperline = 352,
+		.sizeimage = 352 * 288,
+		.colorspace = V4L2_COLORSPACE_SRGB},
+	{640, 480, V4L2_PIX_FMT_SBGGR8, V4L2_FIELD_NONE,
+		.bytesperline = 640,
+		.sizeimage = 640 * 480,
+		.colorspace = V4L2_COLORSPACE_SRGB},
+	{720, 576, V4L2_PIX_FMT_SBGGR8, V4L2_FIELD_NONE,
+		.bytesperline = 720,
+		.sizeimage = 720 * 576,
+		.colorspace = V4L2_COLORSPACE_SRGB},
+	{800, 600, V4L2_PIX_FMT_SBGGR8, V4L2_FIELD_NONE,
+		.bytesperline = 800,
+		.sizeimage = 800 * 600,
+		.colorspace = V4L2_COLORSPACE_SRGB},
+	{1024, 768, V4L2_PIX_FMT_SBGGR8, V4L2_FIELD_NONE,
+		.bytesperline = 1024,
+		.sizeimage = 1024 * 768,
+		.colorspace = V4L2_COLORSPACE_SRGB},
+	{1280, 1024, V4L2_PIX_FMT_SBGGR8, V4L2_FIELD_NONE,
+		.bytesperline = 1280,
+		.sizeimage = 1280 * 1024,
+		.colorspace = V4L2_COLORSPACE_SRGB},
+};
+
+/* -- read a register -- */
+static u8 reg_r(struct gspca_dev *gspca_dev, u16 index)
+{
+	struct usb_device *dev = gspca_dev->dev;
+	int ret;
+
+	if (gspca_dev->usb_err < 0)
+		return 0;
+	ret = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
+			0x00,
+			USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
+			0x00,
+			index,
+			gspca_dev->usb_buf, 1,
+			500);
+
+	PDEBUG(D_USBI, "reg_r 0x%x=0x%02x", index, gspca_dev->usb_buf[0]);
+	if (ret < 0) {
+		pr_err("reg_r 0x%x err %d\n", index, ret);
+		gspca_dev->usb_err = ret;
+		return 0;
+	}
+
+	return gspca_dev->usb_buf[0];
+}
+
+/* -- write a register -- */
+static void reg_w(struct gspca_dev *gspca_dev, u16 index, u8 val)
+{
+	int ret;
+	struct usb_device *dev = gspca_dev->dev;
+
+	if (gspca_dev->usb_err < 0)
+		return;
+	ret = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
+			0x01,
+			USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
+			val,
+			index,
+			NULL,
+			0,
+			500);
+	PDEBUG(D_USBO, "reg_w 0x%x:=0x%02x", index, val);
+	if (ret < 0) {
+		pr_err("reg_w 0x%x err %d\n", index, ret);
+		gspca_dev->usb_err = ret;
+	}
+}
+
+static void reg_w_mask(struct gspca_dev *gspca_dev, u16 index, u8 val, u8 mask)
+{
+	val = (reg_r(gspca_dev, index) & ~mask) | (val & mask);
+	reg_w(gspca_dev, index, val);
+}
+
+/* this function is called at probe time */
+static int sd_config(struct gspca_dev *gspca_dev,
+			const struct usb_device_id *id)
+{
+	gspca_dev->cam.cam_mode = stk1135_modes;
+	gspca_dev->cam.nmodes = ARRAY_SIZE(stk1135_modes);
+	return 0;
+}
+
+static int stk1135_serial_wait_ready(struct gspca_dev *gspca_dev)
+{
+	int i = 0;
+	u8 val;
+
+	do {
+		val = reg_r(gspca_dev, STK1135_REG_SICTL + 1);
+		if (i++ > 500) { /* maximum retry count */
+			pr_err("serial bus timeout: status=0x%02x\n", val);
+			return -1;
+		}
+	/* repeat if BUSY or WRITE/READ not finished */
+	} while ((val & 0x10) || !(val & 0x05));
+
+	return 0;
+}
+
+static u8 sensor_read_8(struct gspca_dev *gspca_dev, u8 addr)
+{
+	reg_w(gspca_dev, STK1135_REG_SBUSR, addr);
+	/* begin read */
+	reg_w(gspca_dev, STK1135_REG_SICTL, 0x20);
+	/* wait until finished */
+	if (stk1135_serial_wait_ready(gspca_dev)) {
+		pr_err("Sensor read failed\n");
+		return 0;
+	}
+
+	return reg_r(gspca_dev, STK1135_REG_SBUSR + 1);
+}
+
+static u16 sensor_read_16(struct gspca_dev *gspca_dev, u8 addr)
+{
+	return (sensor_read_8(gspca_dev, addr) << 8) |
+		sensor_read_8(gspca_dev, 0xf1);
+}
+
+static void sensor_write_8(struct gspca_dev *gspca_dev, u8 addr, u8 data)
+{
+	/* load address and data registers */
+	reg_w(gspca_dev, STK1135_REG_SBUSW, addr);
+	reg_w(gspca_dev, STK1135_REG_SBUSW + 1, data);
+	/* begin write */
+	reg_w(gspca_dev, STK1135_REG_SICTL, 0x01);
+	/* wait until finished */
+	if (stk1135_serial_wait_ready(gspca_dev)) {
+		pr_err("Sensor write failed\n");
+		return;
+	}
+}
+
+static void sensor_write_16(struct gspca_dev *gspca_dev, u8 addr, u16 data)
+{
+	sensor_write_8(gspca_dev, addr, data >> 8);
+	sensor_write_8(gspca_dev, 0xf1, data & 0xff);
+}
+
+static void sensor_set_page(struct gspca_dev *gspca_dev, u8 page)
+{
+	struct sd *sd = (struct sd *) gspca_dev;
+
+	if (page != sd->sensor_page) {
+		sensor_write_16(gspca_dev, 0xf0, page);
+		sd->sensor_page = page;
+	}
+}
+
+static u16 sensor_read(struct gspca_dev *gspca_dev, u16 reg)
+{
+	sensor_set_page(gspca_dev, reg >> 8);
+	return sensor_read_16(gspca_dev, reg & 0xff);
+}
+
+static void sensor_write(struct gspca_dev *gspca_dev, u16 reg, u16 val)
+{
+	sensor_set_page(gspca_dev, reg >> 8);
+	sensor_write_16(gspca_dev, reg & 0xff, val);
+}
+
+static void sensor_write_mask(struct gspca_dev *gspca_dev,
+			u16 reg, u16 val, u16 mask)
+{
+	val = (sensor_read(gspca_dev, reg) & ~mask) | (val & mask);
+	sensor_write(gspca_dev, reg, val);
+}
+
+struct sensor_val {
+	u16 reg;
+	u16 val;
+};
+
+/* configure MT9M112 sensor */
+static void stk1135_configure_mt9m112(struct gspca_dev *gspca_dev)
+{
+	static const struct sensor_val cfg[] = {
+		/* restart&reset, chip enable, reserved */
+		{ 0x00d, 0x000b }, { 0x00d, 0x0008 }, { 0x035, 0x0022 },
+		/* mode ctl: AWB on, AE both, clip aper corr, defect corr, AE */
+		{ 0x106, 0x700e },
+
+		{ 0x2dd, 0x18e0 }, /* B-R thresholds, */
+
+		/* AWB */
+		{ 0x21f, 0x0180 }, /* Cb and Cr limits */
+		{ 0x220, 0xc814 }, { 0x221, 0x8080 }, /* lum limits, RGB gain */
+		{ 0x222, 0xa078 }, { 0x223, 0xa078 }, /* R, B limit */
+		{ 0x224, 0x5f20 }, { 0x228, 0xea02 }, /* mtx adj lim, adv ctl */
+		{ 0x229, 0x867a }, /* wide gates */
+
+		/* Color correction */
+		/* imager gains base, delta, delta signs */
+		{ 0x25e, 0x594c }, { 0x25f, 0x4d51 }, { 0x260, 0x0002 },
+		/* AWB adv ctl 2, gain offs */
+		{ 0x2ef, 0x0008 }, { 0x2f2, 0x0000 },
+		/* base matrix signs, scale K1-5, K6-9 */
+		{ 0x202, 0x00ee }, { 0x203, 0x3923 }, { 0x204, 0x0724 },
+		/* base matrix coef */
+		{ 0x209, 0x00cd }, { 0x20a, 0x0093 }, { 0x20b, 0x0004 },/*K1-3*/
+		{ 0x20c, 0x005c }, { 0x20d, 0x00d9 }, { 0x20e, 0x0053 },/*K4-6*/
+		{ 0x20f, 0x0008 }, { 0x210, 0x0091 }, { 0x211, 0x00cf },/*K7-9*/
+		{ 0x215, 0x0000 }, /* delta mtx signs */
+		/* delta matrix coef */
+		{ 0x216, 0x0000 }, { 0x217, 0x0000 }, { 0x218, 0x0000 },/*D1-3*/
+		{ 0x219, 0x0000 }, { 0x21a, 0x0000 }, { 0x21b, 0x0000 },/*D4-6*/
+		{ 0x21c, 0x0000 }, { 0x21d, 0x0000 }, { 0x21e, 0x0000 },/*D7-9*/
+		/* enable & disable manual WB to apply color corr. settings */
+		{ 0x106, 0xf00e }, { 0x106, 0x700e },
+
+		/* Lens shading correction */
+		{ 0x180, 0x0007 }, /* control */
+		/* vertical knee 0, 2+1, 4+3 */
+		{ 0x181, 0xde13 }, { 0x182, 0xebe2 }, { 0x183, 0x00f6 }, /* R */
+		{ 0x184, 0xe114 }, { 0x185, 0xeadd }, { 0x186, 0xfdf6 }, /* G */
+		{ 0x187, 0xe511 }, { 0x188, 0xede6 }, { 0x189, 0xfbf7 }, /* B */
+		/* horizontal knee 0, 2+1, 4+3, 5 */
+		{ 0x18a, 0xd613 }, { 0x18b, 0xedec }, /* R .. */
+		{ 0x18c, 0xf9f2 }, { 0x18d, 0x0000 }, /* .. R */
+		{ 0x18e, 0xd815 }, { 0x18f, 0xe9ea }, /* G .. */
+		{ 0x190, 0xf9f1 }, { 0x191, 0x0002 }, /* .. G */
+		{ 0x192, 0xde10 }, { 0x193, 0xefef }, /* B .. */
+		{ 0x194, 0xfbf4 }, { 0x195, 0x0002 }, /* .. B */
+		/* vertical knee 6+5, 8+7 */
+		{ 0x1b6, 0x0e06 }, { 0x1b7, 0x2713 }, /* R */
+		{ 0x1b8, 0x1106 }, { 0x1b9, 0x2713 }, /* G */
+		{ 0x1ba, 0x0c03 }, { 0x1bb, 0x2a0f }, /* B */
+		/* horizontal knee 7+6, 9+8, 10 */
+		{ 0x1bc, 0x1208 }, { 0x1bd, 0x1a16 }, { 0x1be, 0x0022 }, /* R */
+		{ 0x1bf, 0x150a }, { 0x1c0, 0x1c1a }, { 0x1c1, 0x002d }, /* G */
+		{ 0x1c2, 0x1109 }, { 0x1c3, 0x1414 }, { 0x1c4, 0x002a }, /* B */
+		{ 0x106, 0x740e }, /* enable lens shading correction */
+
+		/* Gamma correction - context A */
+		{ 0x153, 0x0b03 }, { 0x154, 0x4722 }, { 0x155, 0xac82 },
+		{ 0x156, 0xdac7 }, { 0x157, 0xf5e9 }, { 0x158, 0xff00 },
+		/* Gamma correction - context B */
+		{ 0x1dc, 0x0b03 }, { 0x1dd, 0x4722 }, { 0x1de, 0xac82 },
+		{ 0x1df, 0xdac7 }, { 0x1e0, 0xf5e9 }, { 0x1e1, 0xff00 },
+
+		/* output format: RGB, invert output pixclock, output bayer */
+		{ 0x13a, 0x4300 }, { 0x19b, 0x4300 }, /* for context A, B */
+		{ 0x108, 0x0180 }, /* format control - enable bayer row flip */
+
+		{ 0x22f, 0xd100 }, { 0x29c, 0xd100 }, /* AE A, B */
+
+		/* default prg conf, prg ctl - by 0x2d2, prg advance - PA1 */
+		{ 0x2d2, 0x0000 }, { 0x2cc, 0x0004 }, { 0x2cb, 0x0001 },
+
+		{ 0x22e, 0x0c3c }, { 0x267, 0x1010 }, /* AE tgt ctl, gain lim */
+
+		/* PLL */
+		{ 0x065, 0xa000 }, /* clk ctl - enable PLL (clear bit 14) */
+		{ 0x066, 0x2003 }, { 0x067, 0x0501 }, /* PLL M=128, N=3, P=1 */
+		{ 0x065, 0x2000 }, /* disable PLL bypass (clear bit 15) */
+
+		{ 0x005, 0x01b8 }, { 0x007, 0x00d8 }, /* horiz blanking B, A */
+
+		/* AE line size, shutter delay limit */
+		{ 0x239, 0x06c0 }, { 0x23b, 0x040e }, /* for context A */
+		{ 0x23a, 0x06c0 }, { 0x23c, 0x0564 }, /* for context B */
+		/* shutter width basis 60Hz, 50Hz */
+		{ 0x257, 0x0208 }, { 0x258, 0x0271 }, /* for context A */
+		{ 0x259, 0x0209 }, { 0x25a, 0x0271 }, /* for context B */
+
+		{ 0x25c, 0x120d }, { 0x25d, 0x1712 }, /* flicker 60Hz, 50Hz */
+		{ 0x264, 0x5e1c }, /* reserved */
+		/* flicker, AE gain limits, gain zone limits */
+		{ 0x25b, 0x0003 }, { 0x236, 0x7810 }, { 0x237, 0x8304 },
+
+		{ 0x008, 0x0021 }, /* vert blanking A */
+	};
+	int i;
+	u16 width, height;
+
+	for (i = 0; i < ARRAY_SIZE(cfg); i++)
+		sensor_write(gspca_dev, cfg[i].reg, cfg[i].val);
+
+	/* set output size */
+	width = gspca_dev->cam.cam_mode[gspca_dev->curr_mode].width;
+	height = gspca_dev->cam.cam_mode[gspca_dev->curr_mode].height;
+	if (width <= 640) { /* use context A (half readout speed by default) */
+		sensor_write(gspca_dev, 0x1a7, width);
+		sensor_write(gspca_dev, 0x1aa, height);
+		/* set read mode context A */
+		sensor_write(gspca_dev, 0x0c8, 0x0000);
+		/* set resize, read mode, vblank, hblank context A */
+		sensor_write(gspca_dev, 0x2c8, 0x0000);
+	} else { /* use context B (full readout speed by default) */
+		sensor_write(gspca_dev, 0x1a1, width);
+		sensor_write(gspca_dev, 0x1a4, height);
+		/* set read mode context B */
+		sensor_write(gspca_dev, 0x0c8, 0x0008);
+		/* set resize, read mode, vblank, hblank context B */
+		sensor_write(gspca_dev, 0x2c8, 0x040b);
+	}
+}
+
+static void stk1135_configure_clock(struct gspca_dev *gspca_dev)
+{
+	/* configure SCLKOUT */
+	reg_w(gspca_dev, STK1135_REG_TMGEN, 0x12);
+	/* set 1 clock per pixel */
+	/* and positive edge clocked pulse high when pixel counter = 0 */
+	reg_w(gspca_dev, STK1135_REG_TCP1 + 0, 0x41);
+	reg_w(gspca_dev, STK1135_REG_TCP1 + 1, 0x00);
+	reg_w(gspca_dev, STK1135_REG_TCP1 + 2, 0x00);
+	reg_w(gspca_dev, STK1135_REG_TCP1 + 3, 0x00);
+
+	/* enable CLKOUT for sensor */
+	reg_w(gspca_dev, STK1135_REG_SENSO + 0, 0x10);
+	/* disable STOP clock */
+	reg_w(gspca_dev, STK1135_REG_SENSO + 1, 0x00);
+	/* set lower 8 bits of PLL feedback divider */
+	reg_w(gspca_dev, STK1135_REG_SENSO + 3, 0x07);
+	/* set other PLL parameters */
+	reg_w(gspca_dev, STK1135_REG_PLLFD, 0x06);
+	/* enable timing generator */
+	reg_w(gspca_dev, STK1135_REG_TMGEN, 0x80);
+	/* enable PLL */
+	reg_w(gspca_dev, STK1135_REG_SENSO + 2, 0x04);
+
+	/* set serial interface clock divider (30MHz/0x1f*16+2) = 60240 kHz) */
+	reg_w(gspca_dev, STK1135_REG_SICTL + 2, 0x1f);
+}
+
+static void stk1135_camera_disable(struct gspca_dev *gspca_dev)
+{
+	/* set capture end Y position to 0 */
+	reg_w(gspca_dev, STK1135_REG_CIEPO + 2, 0x00);
+	reg_w(gspca_dev, STK1135_REG_CIEPO + 3, 0x00);
+	/* disable capture */
+	reg_w_mask(gspca_dev, STK1135_REG_SCTRL, 0x00, 0x80);
+
+	/* enable sensor standby and diasble chip enable */
+	sensor_write_mask(gspca_dev, 0x00d, 0x0004, 0x000c);
+
+	/* disable PLL */
+	reg_w_mask(gspca_dev, STK1135_REG_SENSO + 2, 0x00, 0x01);
+	/* disable timing generator */
+	reg_w(gspca_dev, STK1135_REG_TMGEN, 0x00);
+	/* enable STOP clock */
+	reg_w(gspca_dev, STK1135_REG_SENSO + 1, 0x20);
+	/* disable CLKOUT for sensor */
+	reg_w(gspca_dev, STK1135_REG_SENSO, 0x00);
+
+	/* disable sensor (GPIO5) and enable GPIO0,3,6 (?) - sensor standby? */
+	reg_w(gspca_dev, STK1135_REG_GCTRL, 0x49);
+}
+
+/* this function is called at probe and resume time */
+static int sd_init(struct gspca_dev *gspca_dev)
+{
+	u16 sensor_id;
+	char *sensor_name;
+	struct sd *sd = (struct sd *) gspca_dev;
+
+	/* set GPIO3,4,5,6 direction to output */
+	reg_w(gspca_dev, STK1135_REG_GCTRL + 2, 0x78);
+	/* enable sensor (GPIO5) */
+	reg_w(gspca_dev, STK1135_REG_GCTRL, (1 << 5));
+	/* disable ROM interface */
+	reg_w(gspca_dev, STK1135_REG_GCTRL + 3, 0x80);
+	/* enable interrupts from GPIO8 (flip sensor) and GPIO9 (???) */
+	reg_w(gspca_dev, STK1135_REG_ICTRL + 1, 0x00);
+	reg_w(gspca_dev, STK1135_REG_ICTRL + 3, 0x03);
+	/* enable remote wakeup from GPIO9 (???) */
+	reg_w(gspca_dev, STK1135_REG_RMCTL + 1, 0x00);
+	reg_w(gspca_dev, STK1135_REG_RMCTL + 3, 0x02);
+
+	/* reset serial interface */
+	reg_w(gspca_dev, STK1135_REG_SICTL, 0x80);
+	reg_w(gspca_dev, STK1135_REG_SICTL, 0x00);
+	/* set sensor address */
+	reg_w(gspca_dev, STK1135_REG_SICTL + 3, 0xba);
+	/* disable alt 2-wire serial interface */
+	reg_w(gspca_dev, STK1135_REG_ASIC + 3, 0x00);
+
+	stk1135_configure_clock(gspca_dev);
+
+	/* read sensor ID */
+	sd->sensor_page = 0xff;
+	sensor_id = sensor_read(gspca_dev, 0x000);
+
+	switch (sensor_id) {
+	case 0x148c:
+		sensor_name = "MT9M112";
+		break;
+	default:
+		sensor_name = "unknown";
+	}
+	pr_info("Detected sensor type %s (0x%x)\n", sensor_name, sensor_id);
+
+	stk1135_camera_disable(gspca_dev);
+
+	return gspca_dev->usb_err;
+}
+
+/* -- start the camera -- */
+static int sd_start(struct gspca_dev *gspca_dev)
+{
+	struct sd *sd = (struct sd *) gspca_dev;
+	u16 width, height;
+
+	/* enable sensor (GPIO5) */
+	reg_w(gspca_dev, STK1135_REG_GCTRL, (1 << 5));
+
+	stk1135_configure_clock(gspca_dev);
+
+	/* set capture start position X = 0, Y = 0 */
+	reg_w(gspca_dev, STK1135_REG_CISPO + 0, 0x00);
+	reg_w(gspca_dev, STK1135_REG_CISPO + 1, 0x00);
+	reg_w(gspca_dev, STK1135_REG_CISPO + 2, 0x00);
+	reg_w(gspca_dev, STK1135_REG_CISPO + 3, 0x00);
+
+	/* set capture end position */
+	width = gspca_dev->cam.cam_mode[gspca_dev->curr_mode].width;
+	height = gspca_dev->cam.cam_mode[gspca_dev->curr_mode].height;
+	reg_w(gspca_dev, STK1135_REG_CIEPO + 0, width & 0xff);
+	reg_w(gspca_dev, STK1135_REG_CIEPO + 1, width >> 8);
+	reg_w(gspca_dev, STK1135_REG_CIEPO + 2, height & 0xff);
+	reg_w(gspca_dev, STK1135_REG_CIEPO + 3, height >> 8);
+
+	/* set 8-bit mode */
+	reg_w(gspca_dev, STK1135_REG_SCTRL, 0x20);
+
+	stk1135_configure_mt9m112(gspca_dev);
+
+	/* enable capture */
+	reg_w_mask(gspca_dev, STK1135_REG_SCTRL, 0x80, 0x80);
+
+	if (gspca_dev->usb_err >= 0)
+		PDEBUG(D_STREAM, "camera started alt: 0x%02x",
+				gspca_dev->alt);
+
+	sd->pkt_seq = 0;
+
+	return gspca_dev->usb_err;
+}
+
+static void sd_stopN(struct gspca_dev *gspca_dev)
+{
+	struct usb_device *dev = gspca_dev->dev;
+
+	usb_set_interface(dev, gspca_dev->iface, 0);
+
+	stk1135_camera_disable(gspca_dev);
+
+	PDEBUG(D_STREAM, "camera stopped");
+}
+
+static void sd_pkt_scan(struct gspca_dev *gspca_dev,
+			u8 *data,			/* isoc packet */
+			int len)			/* iso packet length */
+{
+	struct sd *sd = (struct sd *) gspca_dev;
+	int skip = sizeof(struct stk1135_pkt_header);
+	bool flip;
+	enum gspca_packet_type pkt_type = INTER_PACKET;
+	struct stk1135_pkt_header *hdr = (void *)data;
+	u8 seq;
+
+	if (len < 4) {
+		PDEBUG(D_PACK, "received short packet (less than 4 bytes)");
+		return;
+	}
+
+	/* GPIO 8 is flip sensor (1 = normal position, 0 = flipped to back) */
+	flip = le16_to_cpu(hdr->gpio) & (1 << 8);
+	/* it's a switch, needs software debounce */
+	if (sd->flip_status != flip)
+		sd->flip_debounce++;
+	else
+		sd->flip_debounce = 0;
+
+	/* check sequence number (not present in new frame packets) */
+	if (!(hdr->flags & STK1135_HDR_FRAME_START)) {
+		seq = hdr->seq & STK1135_HDR_SEQ_MASK;
+		if (seq != sd->pkt_seq) {
+			PDEBUG(D_PACK, "received out-of-sequence packet");
+			/* resync sequence and discard packet */
+			sd->pkt_seq = seq;
+			gspca_dev->last_packet_type = DISCARD_PACKET;
+			return;
+		}
+	}
+	sd->pkt_seq++;
+	if (sd->pkt_seq > STK1135_HDR_SEQ_MASK)
+		sd->pkt_seq = 0;
+
+	if (len == sizeof(struct stk1135_pkt_header))
+		return;
+
+	if (hdr->flags & STK1135_HDR_FRAME_START) { /* new frame */
+		skip = 8;	/* the header is longer */
+		gspca_frame_add(gspca_dev, LAST_PACKET, data, 0);
+		pkt_type = FIRST_PACKET;
+	}
+	gspca_frame_add(gspca_dev, pkt_type, data + skip, len - skip);
+}
+
+static void sethflip(struct gspca_dev *gspca_dev, s32 val)
+{
+	sensor_write_mask(gspca_dev, 0x020, val ? 0x0002 : 0x0000 , 0x0002);
+}
+
+static void setvflip(struct gspca_dev *gspca_dev, s32 val)
+{
+	sensor_write_mask(gspca_dev, 0x020, val ? 0x0001 : 0x0000 , 0x0001);
+}
+
+static void stk1135_dq_callback(struct gspca_dev *gspca_dev)
+{
+	struct sd *sd = (struct sd *) gspca_dev;
+
+	if (sd->flip_debounce > 100) {
+		sethflip(gspca_dev, sd->flip_status);
+		setvflip(gspca_dev, sd->flip_status);
+		sd->flip_status = !sd->flip_status;
+	}
+}
+
+static int sd_s_ctrl(struct v4l2_ctrl *ctrl)
+{
+	struct gspca_dev *gspca_dev =
+		container_of(ctrl->handler, struct gspca_dev, ctrl_handler);
+
+	gspca_dev->usb_err = 0;
+
+	if (!gspca_dev->streaming)
+		return 0;
+
+	switch (ctrl->id) {
+	case V4L2_CID_HFLIP:
+		sethflip(gspca_dev, ctrl->val);
+		break;
+	case V4L2_CID_VFLIP:
+		setvflip(gspca_dev, ctrl->val);
+		break;
+	}
+
+	return gspca_dev->usb_err;
+}
+
+static const struct v4l2_ctrl_ops sd_ctrl_ops = {
+	.s_ctrl = sd_s_ctrl,
+};
+
+static int sd_init_controls(struct gspca_dev *gspca_dev)
+{
+	struct v4l2_ctrl_handler *hdl = &gspca_dev->ctrl_handler;
+
+	gspca_dev->vdev.ctrl_handler = hdl;
+	v4l2_ctrl_handler_init(hdl, 2);
+	v4l2_ctrl_new_std(hdl, &sd_ctrl_ops, V4L2_CID_HFLIP, 0, 1, 1, 0);
+	v4l2_ctrl_new_std(hdl, &sd_ctrl_ops, V4L2_CID_VFLIP, 0, 1, 1, 0);
+
+	if (hdl->error) {
+		pr_err("Could not initialize controls\n");
+		return hdl->error;
+	}
+	return 0;
+}
+
+/* sub-driver description */
+static const struct sd_desc sd_desc = {
+	.name = MODULE_NAME,
+	.config = sd_config,
+	.init = sd_init,
+	.init_controls = sd_init_controls,
+	.start = sd_start,
+	.stopN = sd_stopN,
+	.pkt_scan = sd_pkt_scan,
+	.dq_callback = stk1135_dq_callback,
+};
+
+/* -- module initialisation -- */
+static const struct usb_device_id device_table[] = {
+	{USB_DEVICE(0x174f, 0x6a31)},	/* ASUS laptop, MT9M112 sensor */
+	{}
+};
+MODULE_DEVICE_TABLE(usb, device_table);
+
+/* -- device connect -- */
+static int sd_probe(struct usb_interface *intf,
+			const struct usb_device_id *id)
+{
+	return gspca_dev_probe(intf, id, &sd_desc, sizeof(struct sd),
+				THIS_MODULE);
+}
+
+static struct usb_driver sd_driver = {
+	.name = MODULE_NAME,
+	.id_table = device_table,
+	.probe = sd_probe,
+	.disconnect = gspca_disconnect,
+#ifdef CONFIG_PM
+	.suspend = gspca_suspend,
+	.resume = gspca_resume,
+	.reset_resume = gspca_resume,
+#endif
+};
+
+module_usb_driver(sd_driver);