| Message ID | 20230829101546.483189-2-f.suligoi@asem.it (mailing list archive) |
|---|---|
| State | Handled Elsewhere |
| Headers | show |
| Series | [v1,1/2] dt-bindings: backlight: Add MPS MP3309C | expand |
On 29/08/2023 12:15, Flavio Suligoi wrote: > The Monolithic Power (MPS) MP3309C is a WLED step-up converter, featuring a > programmable switching frequency to optimize efficiency. > The brightness can be controlled either by I2C commands (called "analog" > mode) or by a PWM input signal (PWM mode). > This driver supports both modes. > > For DT configuration details, please refer to: > - Documentation/devicetree/bindings/leds/backlight/mps,mp3309c.yaml > > The datasheet is available at: > - https://www.monolithicpower.com/en/mp3309c.html > > Signed-off-by: Flavio Suligoi <f.suligoi@asem.it> > --- > MAINTAINERS | 6 + > drivers/video/backlight/Kconfig | 13 + > drivers/video/backlight/Makefile | 1 + > drivers/video/backlight/mp3309c_bl.c | 491 +++++++++++++++++++++++++++ > 4 files changed, 511 insertions(+) > create mode 100644 drivers/video/backlight/mp3309c_bl.c > > diff --git a/MAINTAINERS b/MAINTAINERS > index 3be1bdfe8ecc..895c56ff4f1e 100644 > --- a/MAINTAINERS > +++ b/MAINTAINERS > @@ -14333,6 +14333,12 @@ S: Maintained > F: Documentation/driver-api/tty/moxa-smartio.rst > F: drivers/tty/mxser.* > > +MP3309C BACKLIGHT DRIVER > +M: Flavio Suligoi <f.suligoi@asem.it> > +S: Maintained > +F: Documentation/devicetree/bindings/leds/backlight/mps,mp3309c.yaml > +F: drivers/video/backlight/mp3309c_bl.c > + > MR800 AVERMEDIA USB FM RADIO DRIVER > M: Alexey Klimov <klimov.linux@gmail.com> > L: linux-media@vger.kernel.org > diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig > index 51387b1ef012..65d0ac9f611d 100644 > --- a/drivers/video/backlight/Kconfig > +++ b/drivers/video/backlight/Kconfig > @@ -389,6 +389,19 @@ config BACKLIGHT_LM3639 > help > This supports TI LM3639 Backlight + 1.5A Flash LED Driver > > +config BACKLIGHT_MP3309C Why is this placed between LM and LP entries? Keep things ordered. > + tristate "Backlight Driver for MPS MP3309C" > + depends on I2C > + select REGMAP_I2C > + select NEW_LEDS > + select LEDS_CLASS > + help > + This supports MPS MP3309C backlight WLED Driver in both PWM and > + analog/I2C dimming modes. > + > + To compile this driver as a module, choose M here: the module will > + be called mp3309c_bl. > + > config BACKLIGHT_LP855X > tristate "Backlight driver for TI LP855X" > depends on I2C && PWM > diff --git a/drivers/video/backlight/Makefile b/drivers/video/backlight/Makefile > index f72e1c3c59e9..c42c5bccc5ac 100644 > --- a/drivers/video/backlight/Makefile > +++ b/drivers/video/backlight/Makefile > @@ -44,6 +44,7 @@ obj-$(CONFIG_BACKLIGHT_LP855X) += lp855x_bl.o > obj-$(CONFIG_BACKLIGHT_LP8788) += lp8788_bl.o > obj-$(CONFIG_BACKLIGHT_LV5207LP) += lv5207lp.o > obj-$(CONFIG_BACKLIGHT_MAX8925) += max8925_bl.o > +obj-$(CONFIG_BACKLIGHT_MP3309C) += mp3309c_bl.o > obj-$(CONFIG_BACKLIGHT_MT6370) += mt6370-backlight.o > obj-$(CONFIG_BACKLIGHT_OMAP1) += omap1_bl.o > obj-$(CONFIG_BACKLIGHT_PANDORA) += pandora_bl.o > diff --git a/drivers/video/backlight/mp3309c_bl.c b/drivers/video/backlight/mp3309c_bl.c > new file mode 100644 > index 000000000000..7cb7a542ceca > --- /dev/null > +++ b/drivers/video/backlight/mp3309c_bl.c > @@ -0,0 +1,491 @@ > +// SPDX-License-Identifier: GPL-2.0+ > +/* > + * Driver for MPS MP3309C White LED driver with I2C interface > + * > + * Copyright (C) 2023 ASEM Srl > + * Author: Flavio Suligoi <f.suligoi@asem.it> > + */ > + > +#include <linux/backlight.h> > +#include <linux/delay.h> > +#include <linux/gpio/consumer.h> > +#include <linux/i2c.h> > +#include <linux/pwm.h> > +#include <linux/regmap.h> > +#include <linux/workqueue.h> > + > +#define REG_I2C_0 0x00 > +#define REG_I2C_1 0x01 > + > +#define REG_I2C_0_EN 0x80 > +#define REG_I2C_0_D0 0x40 > +#define REG_I2C_0_D1 0x20 > +#define REG_I2C_0_D2 0x10 > +#define REG_I2C_0_D3 0x08 > +#define REG_I2C_0_D4 0x04 > +#define REG_I2C_0_RSRV1 0x02 > +#define REG_I2C_0_RSRV2 0x01 > + > +#define REG_I2C_1_RSRV1 0x80 > +#define REG_I2C_1_DIMS 0x40 > +#define REG_I2C_1_SYNC 0x20 > +#define REG_I2C_1_OVP0 0x10 > +#define REG_I2C_1_OVP1 0x08 > +#define REG_I2C_1_VOS 0x04 > +#define REG_I2C_1_LEDO 0x02 > +#define REG_I2C_1_OTP 0x01 > + > +#define ANALOG_MAX_VAL 31 > +#define ANALOG_REG_MASK 0x7c > + > +enum backlight_status { > + FIRST_POWER_ON, > + BACKLIGHT_OFF, > + BACKLIGHT_ON, > +}; > + > +enum dimming_mode_value { > + DIMMING_PWM, > + DIMMING_ANALOG_I2C, > +}; > + > +struct mp3309c_platform_data { > + u32 max_brightness; > + u32 brightness; > + u32 switch_on_delay_ms; > + u32 switch_off_delay_ms; > + u32 reset_on_delay_ms; > + u32 reset_on_length_ms; > + u8 dimming_mode; > + u8 reset_pulse_enable; > + u8 over_voltage_protection; > + > + unsigned int status; > +}; > + > +struct mp3309c_chip { > + struct device *dev; > + struct mp3309c_platform_data *pdata; > + struct backlight_device *bl; > + struct gpio_desc *enable_gpio; > + struct regmap *regmap; > + struct pwm_device *pwmd; > + > + struct delayed_work enable_work; > + struct delayed_work reset_gpio_work; > + int irq; > + > + struct gpio_desc *reset_gpio; > +}; > + > +static const struct regmap_config mp3309c_regmap = { > + .name = "mp3309c_regmap", > + .reg_bits = 8, > + .reg_stride = 1, > + .val_bits = 8, > + .max_register = REG_I2C_1, > +}; > + > +static int pm3309c_parse_dt_node(struct mp3309c_chip *chip, > + struct mp3309c_platform_data *pdata) This should be just before probe function. It is part of probe path. > +{ > + struct device_node *node = chip->dev->of_node; > + const char *tmp_string; > + int ret; > + > + if (!node) { > + dev_err(chip->dev, "failed to get DT node\n"); > + return -ENODEV; > + } > + > + /* > + * Dimming mode: the MP3309C provides two dimming methods: > + * > + * - PWM mode > + * - Analog by I2C control mode > + */ > + ret = of_property_read_string(node, "mps,dimming-mode", &tmp_string); > + if (ret < 0) { > + dev_err(chip->dev, "missed dimming-mode in DT\n"); > + return ret; > + } > + if (!strcmp(tmp_string, "pwm")) { > + dev_info(chip->dev, "dimming method: PWM\n"); Drop > + pdata->dimming_mode = DIMMING_PWM; > + } > + if (!strcmp(tmp_string, "analog-i2c")) { > + dev_info(chip->dev, "dimming method: analog by I2C commands\n"); Drop > + pdata->dimming_mode = DIMMING_ANALOG_I2C; > + } > + > + /* PWM steps (levels): 0 .. max_brightness */ > + ret = of_property_read_u32(node, "max-brightness", > + &pdata->max_brightness); > + if (ret < 0) { > + dev_err(chip->dev, "failed to get max-brightness from DT\n"); > + return ret; > + } > + > + /* Default brightness at startup */ > + ret = of_property_read_u32(node, "default-brightness", > + &pdata->brightness); > + if (ret < 0) { > + dev_err(chip->dev, > + "failed to get default-brightness from DT\n"); > + return ret; > + } > + > + /* > + * Optional backlight switch-on/off delay > + * > + * Note: set 10ms as minimal value for switch-on delay, to stabilize > + * video data > + */ > + pdata->switch_on_delay_ms = 50; > + of_property_read_u32(node, "mps,switch-on-delay-ms", > + &pdata->switch_on_delay_ms); > + if (pdata->switch_on_delay_ms < 10) { > + pdata->switch_on_delay_ms = 10; You miss constraints in the bindings. > + dev_warn(chip->dev, > + "switch-on-delay-ms set to 10ms as minimal value\n"); > + } > + pdata->switch_off_delay_ms = 0; > + of_property_read_u32(node, "mps,switch-off-delay-ms", > + &pdata->switch_off_delay_ms); > + > + /* > + * Reset: GPIO, initial delay and pulse length > + * > + * Use this optional GPIO to reset an external device (LCD panel, video > + * FPGA, etc) when the backlight is switched on > + */ > + pdata->reset_pulse_enable = 0; > + chip->reset_gpio = devm_gpiod_get_optional(chip->dev, "mps,reset", > + GPIOD_OUT_LOW); > + if (IS_ERR(chip->reset_gpio)) { > + ret = PTR_ERR(chip->reset_gpio); > + dev_err(chip->dev, "error acquiring reset gpio: %d\n", ret); > + return ret; return dev_err_probe() > + } > + if (chip->reset_gpio) { > + pdata->reset_pulse_enable = 1; > + > + pdata->reset_on_delay_ms = 10; > + of_property_read_u32(node, "mps,reset-on-delay-ms", > + &pdata->reset_on_delay_ms); > + pdata->reset_on_length_ms = 10; > + of_property_read_u32(node, "mps,reset-on-length-ms", > + &pdata->reset_on_length_ms); > + } > + > + /* > + * Over-voltage protection (OVP) > + * > + * These (optional) properties are: > + * > + * - overvoltage-protection-13v --> OVP point set to 13.5V > + * - overvoltage-protection-24v --> OVP point set to 24V > + * - overvoltage-protection-35v --> OVP point set to 35.5V > + * > + * If not chosen, the hw default value for OVP is 35.5V > + */ > + pdata->over_voltage_protection = REG_I2C_1_OVP1; > + if (of_property_read_bool(node, "mps,overvoltage-protection-13v")) > + pdata->over_voltage_protection = 0x00; > + if (of_property_read_bool(node, "mps,overvoltage-protection-24v")) > + pdata->over_voltage_protection = REG_I2C_1_OVP0; > + if (of_property_read_bool(node, "mps,overvoltage-protection-35v")) > + pdata->over_voltage_protection = REG_I2C_1_OVP1; > + > + return 0; > +} > + ... > + > +static const struct backlight_ops mp3309c_bl_ops = { > + .update_status = mp3309c_bl_update_status, > +}; > + > +static int mp3309c_probe(struct i2c_client *client) > +{ > + struct mp3309c_platform_data *pdata = dev_get_platdata(&client->dev); > + struct mp3309c_chip *chip; > + struct backlight_properties props; > + int ret; > + > + if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) { > + dev_err(&client->dev, "failed to check i2c functionality\n"); > + return -EOPNOTSUPP; > + } > + > + chip = devm_kzalloc(&client->dev, sizeof(struct mp3309c_chip), sizeof(*) > + GFP_KERNEL); > + if (!chip) > + return -ENOMEM; > + chip->dev = &client->dev; > + > + chip->regmap = devm_regmap_init_i2c(client, &mp3309c_regmap); > + if (IS_ERR(chip->regmap)) { > + ret = PTR_ERR(chip->regmap); > + dev_err(&client->dev, "failed to allocate register map\n"); Are you sure regmap allocation should be followed by error message? Allocations must not... so if this is not allocation, then syntax is: return dev_err_probe() > + return ret; > + } > + > + i2c_set_clientdata(client, chip); > + > + if (!pdata) { > + pdata = devm_kzalloc(chip->dev, > + sizeof(struct mp3309c_platform_data), sizeof(*) > + GFP_KERNEL); > + if (!pdata) > + return -ENOMEM; > + > + ret = pm3309c_parse_dt_node(chip, pdata); > + if (ret) { > + dev_err(&client->dev, "failed parsing DT node\n"); Why do you print errors multiple times? parse_dt_node already does it. > + return ret; > + } > + } > + chip->pdata = pdata; > + > + chip->enable_gpio = devm_gpiod_get_optional(&client->dev, "enable", > + GPIOD_OUT_HIGH); > + if (IS_ERR(chip->enable_gpio)) { > + ret = PTR_ERR(chip->enable_gpio); > + return ret; return dev_err_probe() > + } > + > + /* Backlight */ > + props.type = BACKLIGHT_RAW; > + props.brightness = pdata->brightness; > + props.max_brightness = pdata->max_brightness; > + props.scale = BACKLIGHT_SCALE_LINEAR; > + chip->bl = > + devm_backlight_device_register(chip->dev, "mp3309c_bl", > + chip->dev, chip, &mp3309c_bl_ops, > + &props); > + if (IS_ERR(chip->bl)) { > + dev_err(&client->dev, "failed registering backlight\n"); > + return PTR_ERR(chip->bl); return dev_err_probe() > + } > + pdata->status = FIRST_POWER_ON; > + > + /* Enable PWM, if required */ > + if (pdata->dimming_mode == DIMMING_PWM) { > + chip->pwmd = devm_pwm_get(chip->dev, NULL); > + if (IS_ERR(chip->pwmd)) { > + dev_err(&client->dev, "failed getting pwm device\n"); > + return PTR_ERR(chip->pwmd); return dev_err_probe() > + } > + pwm_apply_args(chip->pwmd); > + } > + > + /* > + * Workqueue for delayed backlight enabling > + */ > + INIT_DELAYED_WORK(&chip->enable_work, mp3309c_enable); > + > + /* > + * Workqueue for (optional) external device GPIO reset > + */ > + if (pdata->reset_pulse_enable) { > + dev_info(&client->dev, "reset pulse enabled\n"); Drop, not really helpful. > + INIT_DELAYED_WORK(&chip->reset_gpio_work, mp3309c_reset_gpio); > + } > + > + dev_info(&client->dev, "MP3309C backlight initialized"); Drop simple tracing messages. > + return 0; > +} > + > +static int mp3309c_backlight_switch_off(struct pwm_device *pwmd) > +{ > + struct pwm_state pwmstate; > + > + /* Switch-off the backlight */ > + pwm_get_state(pwmd, &pwmstate); > + pwmstate.duty_cycle = 0; > + pwmstate.enabled = false; > + pwm_apply_state(pwmd, &pwmstate); > + > + return 0; > +} > + > +static void mp3309c_remove(struct i2c_client *client) > +{ > + struct mp3309c_chip *chip = i2c_get_clientdata(client); > + > + if (chip->pdata->dimming_mode == DIMMING_PWM) > + mp3309c_backlight_switch_off(chip->pwmd); > + if (chip->pdata->reset_pulse_enable) > + cancel_delayed_work(&chip->reset_gpio_work); > +} > + > +static void mp3309c_shutdown(struct i2c_client *client) > +{ > + struct mp3309c_chip *chip = i2c_get_clientdata(client); > + > + if (chip->pdata->dimming_mode == DIMMING_PWM) > + mp3309c_backlight_switch_off(chip->pwmd); Why do you need shutdown function? > +} > + > +static const struct of_device_id mp3309c_match_table[] = { > + { .compatible = "mps,mp3309c-backlight", }, > + { }, > +}; > +MODULE_DEVICE_TABLE(of, mp3309c_match_table); > + Best regards, Krzysztof
On Tue, Aug 29, 2023 at 12:15:46PM +0200, Flavio Suligoi wrote: > The Monolithic Power (MPS) MP3309C is a WLED step-up converter, featuring a > programmable switching frequency to optimize efficiency. > The brightness can be controlled either by I2C commands (called "analog" > mode) or by a PWM input signal (PWM mode). > This driver supports both modes. > > For DT configuration details, please refer to: > - Documentation/devicetree/bindings/leds/backlight/mps,mp3309c.yaml > > The datasheet is available at: > - https://www.monolithicpower.com/en/mp3309c.html > > Signed-off-by: Flavio Suligoi <f.suligoi@asem.it> > diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig > index 51387b1ef012..65d0ac9f611d 100644 > --- a/drivers/video/backlight/Kconfig > +++ b/drivers/video/backlight/Kconfig > @@ -389,6 +389,19 @@ config BACKLIGHT_LM3639 > help > This supports TI LM3639 Backlight + 1.5A Flash LED Driver > > +config BACKLIGHT_MP3309C > + tristate "Backlight Driver for MPS MP3309C" > + depends on I2C > + select REGMAP_I2C > + select NEW_LEDS > + select LEDS_CLASS This doesn't seem right. Shouldn't PWM and GPIOLIB be listed here? Why are NEW_LEDS and LEDS_CLASS needed? > + help > + This supports MPS MP3309C backlight WLED Driver in both PWM and > + analog/I2C dimming modes. > + > + To compile this driver as a module, choose M here: the module will > + be called mp3309c_bl. > + > config BACKLIGHT_LP855X > tristate "Backlight driver for TI LP855X" > depends on I2C && PWM > +static int mp3309c_bl_update_status(struct backlight_device *bl) > +{ > + struct mp3309c_chip *chip = bl_get_data(bl); > + int brightness = backlight_get_brightness(bl); > + struct pwm_state pwmstate; > + unsigned int analog_val, bits_val; > + int i, ret; > + > + if (chip->pdata->dimming_mode == DIMMING_PWM) { > + /* > + * PWM dimming mode > + */ > + pwm_init_state(chip->pwmd, &pwmstate); > + pwm_set_relative_duty_cycle(&pwmstate, brightness, > + chip->pdata->max_brightness); > + pwmstate.enabled = true; > + ret = pwm_apply_state(chip->pwmd, &pwmstate); > + if (ret) > + return ret; > + } else { > + /* > + * Analog dimming mode by I2C commands > + * > + * The 5 bits of the dimming analog value D4..D0 is allocated > + * in the I2C register #0, in the following way: > + * > + * +--+--+--+--+--+--+--+--+ > + * |EN|D0|D1|D2|D3|D4|XX|XX| > + * +--+--+--+--+--+--+--+--+ > + */ > + analog_val = DIV_ROUND_UP(ANALOG_MAX_VAL * brightness, > + chip->pdata->max_brightness); > + bits_val = 0; > + for (i = 0; i <= 5; i++) > + bits_val += ((analog_val >> i) & 0x01) << (6 - i); > + ret = regmap_update_bits(chip->regmap, REG_I2C_0, > + ANALOG_REG_MASK, bits_val); > + if (ret) > + return ret; > + } > + > + if (brightness > 0) { > + switch (chip->pdata->status) { > + case FIRST_POWER_ON: > + /* > + * Only for the first time, wait for the optional > + * switch-on delay and then enable the device. > + * Otherwise enable the backlight immediately. > + */ > + schedule_delayed_work(&chip->enable_work, > + msecs_to_jiffies(chip->pdata->switch_on_delay_ms)); Delaying this work makes no sense to me, especially when it is only going to happen at initial power on. If you are (ab)using this property to try and sequence the backlight power-on with display initialization then this is not the way to do it. Normally backlight drivers that support sequencing versus the panel work by having a backlight property set on the panel linking it to the backlight. When the panel is ready this power status of the backlight will be updated accordingly. All the backlight driver need do is make sure that is the initial power status is "powerdown" on systems when the link is present (e.g. leave the backlight off and wait to be told the display has settled). > + /* > + * Optional external device GPIO reset, with > + * delay pulse length > + */ > + if (chip->pdata->reset_pulse_enable) > + schedule_delayed_work(&chip->reset_gpio_work, > + msecs_to_jiffies(chip->pdata->reset_on_delay_ms)); Similarly I don't understand what this property is for. A backlight is directly perceivable by the user. There is nothing downstream of a light that needs to be reset! What is this used for? Daniel.
HI Daniel, > -----Original Message----- > From: Daniel Thompson <daniel.thompson@linaro.org> > Sent: Tuesday, August 29, 2023 6:28 PM > To: Flavio Suligoi <f.suligoi@asem.it> > Cc: Lee Jones <lee@kernel.org>; Jingoo Han <jingoohan1@gmail.com>; Helge > Deller <deller@gmx.de>; Pavel Machek <pavel@ucw.cz>; Rob Herring > <robh+dt@kernel.org>; Krzysztof Kozlowski > <krzysztof.kozlowski+dt@linaro.org>; Conor Dooley <conor+dt@kernel.org>; > dri-devel@lists.freedesktop.org; linux-leds@vger.kernel.org; > devicetree@vger.kernel.org; linux-fbdev@vger.kernel.org; linux- > kernel@vger.kernel.org > Subject: Re: [PATCH v1 2/2] backlight: mp3309c: Add support for MPS > MP3309C > > On Tue, Aug 29, 2023 at 12:15:46PM +0200, Flavio Suligoi wrote: > > The Monolithic Power (MPS) MP3309C is a WLED step-up converter, > > featuring a programmable switching frequency to optimize efficiency. > > The brightness can be controlled either by I2C commands (called "analog" > > mode) or by a PWM input signal (PWM mode). > > This driver supports both modes. > > > > For DT configuration details, please refer to: > > - Documentation/devicetree/bindings/leds/backlight/mps,mp3309c.yaml > > > > The datasheet is available at: > > - https://www.monolithicpower.com/en/mp3309c.html > > > > Signed-off-by: Flavio Suligoi <f.suligoi@asem.it> > > > diff --git a/drivers/video/backlight/Kconfig > > b/drivers/video/backlight/Kconfig index 51387b1ef012..65d0ac9f611d > > 100644 > > --- a/drivers/video/backlight/Kconfig > > +++ b/drivers/video/backlight/Kconfig > > @@ -389,6 +389,19 @@ config BACKLIGHT_LM3639 > > help > > This supports TI LM3639 Backlight + 1.5A Flash LED Driver > > > > +config BACKLIGHT_MP3309C > > + tristate "Backlight Driver for MPS MP3309C" > > + depends on I2C > > + select REGMAP_I2C > > + select NEW_LEDS > > + select LEDS_CLASS > > This doesn't seem right. > > Shouldn't PWM and GPIOLIB be listed here? Why are NEW_LEDS and > LEDS_CLASS needed? ok, I'll fix it > > > + help > > + This supports MPS MP3309C backlight WLED Driver in both PWM > and > > + analog/I2C dimming modes. > > + > > + To compile this driver as a module, choose M here: the module will > > + be called mp3309c_bl. > > + > > config BACKLIGHT_LP855X > > tristate "Backlight driver for TI LP855X" > > depends on I2C && PWM > > > +static int mp3309c_bl_update_status(struct backlight_device *bl) { > > + struct mp3309c_chip *chip = bl_get_data(bl); > > + int brightness = backlight_get_brightness(bl); > > + struct pwm_state pwmstate; > > + unsigned int analog_val, bits_val; > > + int i, ret; > > + > > + if (chip->pdata->dimming_mode == DIMMING_PWM) { > > + /* > > + * PWM dimming mode > > + */ > > + pwm_init_state(chip->pwmd, &pwmstate); > > + pwm_set_relative_duty_cycle(&pwmstate, brightness, > > + chip->pdata->max_brightness); > > + pwmstate.enabled = true; > > + ret = pwm_apply_state(chip->pwmd, &pwmstate); > > + if (ret) > > + return ret; > > + } else { > > + /* > > + * Analog dimming mode by I2C commands > > + * > > + * The 5 bits of the dimming analog value D4..D0 is allocated > > + * in the I2C register #0, in the following way: > > + * > > + * +--+--+--+--+--+--+--+--+ > > + * |EN|D0|D1|D2|D3|D4|XX|XX| > > + * +--+--+--+--+--+--+--+--+ > > + */ > > + analog_val = DIV_ROUND_UP(ANALOG_MAX_VAL * > brightness, > > + chip->pdata->max_brightness); > > + bits_val = 0; > > + for (i = 0; i <= 5; i++) > > + bits_val += ((analog_val >> i) & 0x01) << (6 - i); > > + ret = regmap_update_bits(chip->regmap, REG_I2C_0, > > + ANALOG_REG_MASK, bits_val); > > + if (ret) > > + return ret; > > + } > > + > > + if (brightness > 0) { > > + switch (chip->pdata->status) { > > + case FIRST_POWER_ON: > > + /* > > + * Only for the first time, wait for the optional > > + * switch-on delay and then enable the device. > > + * Otherwise enable the backlight immediately. > > + */ > > + schedule_delayed_work(&chip->enable_work, > > + msecs_to_jiffies(chip->pdata- > >switch_on_delay_ms)); > > Delaying this work makes no sense to me, especially when it is only going to > happen at initial power on. > > If you are (ab)using this property to try and sequence the backlight power-on > with display initialization then this is not the way to do it. > Normally backlight drivers that support sequencing versus the panel work by > having a backlight property set on the panel linking it to the backlight. When > the panel is ready this power status of the backlight will be updated > accordingly. > > All the backlight driver need do is make sure that is the initial power status is > "powerdown" on systems when the link is present (e.g. > leave the backlight off and wait to be told the display has settled). OK, I'll remove this delay. It was used for one of our boards, as a workaround. > > > > + /* > > + * Optional external device GPIO reset, with > > + * delay pulse length > > + */ > > + if (chip->pdata->reset_pulse_enable) > > + schedule_delayed_work(&chip- > >reset_gpio_work, > > + msecs_to_jiffies(chip- > >pdata->reset_on_delay_ms)); > > Similarly I don't understand what this property is for. A backlight is directly > perceivable by the user. There is nothing downstream of a light that needs to > be reset! > > What is this used for? Also this property, this gpio, was used for one of our boards. It is not necessary, I'll remove it. > > > Daniel. Thanks, Daniel! Flavio
diff --git a/MAINTAINERS b/MAINTAINERS index 3be1bdfe8ecc..895c56ff4f1e 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -14333,6 +14333,12 @@ S: Maintained F: Documentation/driver-api/tty/moxa-smartio.rst F: drivers/tty/mxser.* +MP3309C BACKLIGHT DRIVER +M: Flavio Suligoi <f.suligoi@asem.it> +S: Maintained +F: Documentation/devicetree/bindings/leds/backlight/mps,mp3309c.yaml +F: drivers/video/backlight/mp3309c_bl.c + MR800 AVERMEDIA USB FM RADIO DRIVER M: Alexey Klimov <klimov.linux@gmail.com> L: linux-media@vger.kernel.org diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig index 51387b1ef012..65d0ac9f611d 100644 --- a/drivers/video/backlight/Kconfig +++ b/drivers/video/backlight/Kconfig @@ -389,6 +389,19 @@ config BACKLIGHT_LM3639 help This supports TI LM3639 Backlight + 1.5A Flash LED Driver +config BACKLIGHT_MP3309C + tristate "Backlight Driver for MPS MP3309C" + depends on I2C + select REGMAP_I2C + select NEW_LEDS + select LEDS_CLASS + help + This supports MPS MP3309C backlight WLED Driver in both PWM and + analog/I2C dimming modes. + + To compile this driver as a module, choose M here: the module will + be called mp3309c_bl. + config BACKLIGHT_LP855X tristate "Backlight driver for TI LP855X" depends on I2C && PWM diff --git a/drivers/video/backlight/Makefile b/drivers/video/backlight/Makefile index f72e1c3c59e9..c42c5bccc5ac 100644 --- a/drivers/video/backlight/Makefile +++ b/drivers/video/backlight/Makefile @@ -44,6 +44,7 @@ obj-$(CONFIG_BACKLIGHT_LP855X) += lp855x_bl.o obj-$(CONFIG_BACKLIGHT_LP8788) += lp8788_bl.o obj-$(CONFIG_BACKLIGHT_LV5207LP) += lv5207lp.o obj-$(CONFIG_BACKLIGHT_MAX8925) += max8925_bl.o +obj-$(CONFIG_BACKLIGHT_MP3309C) += mp3309c_bl.o obj-$(CONFIG_BACKLIGHT_MT6370) += mt6370-backlight.o obj-$(CONFIG_BACKLIGHT_OMAP1) += omap1_bl.o obj-$(CONFIG_BACKLIGHT_PANDORA) += pandora_bl.o diff --git a/drivers/video/backlight/mp3309c_bl.c b/drivers/video/backlight/mp3309c_bl.c new file mode 100644 index 000000000000..7cb7a542ceca --- /dev/null +++ b/drivers/video/backlight/mp3309c_bl.c @@ -0,0 +1,491 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Driver for MPS MP3309C White LED driver with I2C interface + * + * Copyright (C) 2023 ASEM Srl + * Author: Flavio Suligoi <f.suligoi@asem.it> + */ + +#include <linux/backlight.h> +#include <linux/delay.h> +#include <linux/gpio/consumer.h> +#include <linux/i2c.h> +#include <linux/pwm.h> +#include <linux/regmap.h> +#include <linux/workqueue.h> + +#define REG_I2C_0 0x00 +#define REG_I2C_1 0x01 + +#define REG_I2C_0_EN 0x80 +#define REG_I2C_0_D0 0x40 +#define REG_I2C_0_D1 0x20 +#define REG_I2C_0_D2 0x10 +#define REG_I2C_0_D3 0x08 +#define REG_I2C_0_D4 0x04 +#define REG_I2C_0_RSRV1 0x02 +#define REG_I2C_0_RSRV2 0x01 + +#define REG_I2C_1_RSRV1 0x80 +#define REG_I2C_1_DIMS 0x40 +#define REG_I2C_1_SYNC 0x20 +#define REG_I2C_1_OVP0 0x10 +#define REG_I2C_1_OVP1 0x08 +#define REG_I2C_1_VOS 0x04 +#define REG_I2C_1_LEDO 0x02 +#define REG_I2C_1_OTP 0x01 + +#define ANALOG_MAX_VAL 31 +#define ANALOG_REG_MASK 0x7c + +enum backlight_status { + FIRST_POWER_ON, + BACKLIGHT_OFF, + BACKLIGHT_ON, +}; + +enum dimming_mode_value { + DIMMING_PWM, + DIMMING_ANALOG_I2C, +}; + +struct mp3309c_platform_data { + u32 max_brightness; + u32 brightness; + u32 switch_on_delay_ms; + u32 switch_off_delay_ms; + u32 reset_on_delay_ms; + u32 reset_on_length_ms; + u8 dimming_mode; + u8 reset_pulse_enable; + u8 over_voltage_protection; + + unsigned int status; +}; + +struct mp3309c_chip { + struct device *dev; + struct mp3309c_platform_data *pdata; + struct backlight_device *bl; + struct gpio_desc *enable_gpio; + struct regmap *regmap; + struct pwm_device *pwmd; + + struct delayed_work enable_work; + struct delayed_work reset_gpio_work; + int irq; + + struct gpio_desc *reset_gpio; +}; + +static const struct regmap_config mp3309c_regmap = { + .name = "mp3309c_regmap", + .reg_bits = 8, + .reg_stride = 1, + .val_bits = 8, + .max_register = REG_I2C_1, +}; + +static int pm3309c_parse_dt_node(struct mp3309c_chip *chip, + struct mp3309c_platform_data *pdata) +{ + struct device_node *node = chip->dev->of_node; + const char *tmp_string; + int ret; + + if (!node) { + dev_err(chip->dev, "failed to get DT node\n"); + return -ENODEV; + } + + /* + * Dimming mode: the MP3309C provides two dimming methods: + * + * - PWM mode + * - Analog by I2C control mode + */ + ret = of_property_read_string(node, "mps,dimming-mode", &tmp_string); + if (ret < 0) { + dev_err(chip->dev, "missed dimming-mode in DT\n"); + return ret; + } + if (!strcmp(tmp_string, "pwm")) { + dev_info(chip->dev, "dimming method: PWM\n"); + pdata->dimming_mode = DIMMING_PWM; + } + if (!strcmp(tmp_string, "analog-i2c")) { + dev_info(chip->dev, "dimming method: analog by I2C commands\n"); + pdata->dimming_mode = DIMMING_ANALOG_I2C; + } + + /* PWM steps (levels): 0 .. max_brightness */ + ret = of_property_read_u32(node, "max-brightness", + &pdata->max_brightness); + if (ret < 0) { + dev_err(chip->dev, "failed to get max-brightness from DT\n"); + return ret; + } + + /* Default brightness at startup */ + ret = of_property_read_u32(node, "default-brightness", + &pdata->brightness); + if (ret < 0) { + dev_err(chip->dev, + "failed to get default-brightness from DT\n"); + return ret; + } + + /* + * Optional backlight switch-on/off delay + * + * Note: set 10ms as minimal value for switch-on delay, to stabilize + * video data + */ + pdata->switch_on_delay_ms = 50; + of_property_read_u32(node, "mps,switch-on-delay-ms", + &pdata->switch_on_delay_ms); + if (pdata->switch_on_delay_ms < 10) { + pdata->switch_on_delay_ms = 10; + dev_warn(chip->dev, + "switch-on-delay-ms set to 10ms as minimal value\n"); + } + pdata->switch_off_delay_ms = 0; + of_property_read_u32(node, "mps,switch-off-delay-ms", + &pdata->switch_off_delay_ms); + + /* + * Reset: GPIO, initial delay and pulse length + * + * Use this optional GPIO to reset an external device (LCD panel, video + * FPGA, etc) when the backlight is switched on + */ + pdata->reset_pulse_enable = 0; + chip->reset_gpio = devm_gpiod_get_optional(chip->dev, "mps,reset", + GPIOD_OUT_LOW); + if (IS_ERR(chip->reset_gpio)) { + ret = PTR_ERR(chip->reset_gpio); + dev_err(chip->dev, "error acquiring reset gpio: %d\n", ret); + return ret; + } + if (chip->reset_gpio) { + pdata->reset_pulse_enable = 1; + + pdata->reset_on_delay_ms = 10; + of_property_read_u32(node, "mps,reset-on-delay-ms", + &pdata->reset_on_delay_ms); + pdata->reset_on_length_ms = 10; + of_property_read_u32(node, "mps,reset-on-length-ms", + &pdata->reset_on_length_ms); + } + + /* + * Over-voltage protection (OVP) + * + * These (optional) properties are: + * + * - overvoltage-protection-13v --> OVP point set to 13.5V + * - overvoltage-protection-24v --> OVP point set to 24V + * - overvoltage-protection-35v --> OVP point set to 35.5V + * + * If not chosen, the hw default value for OVP is 35.5V + */ + pdata->over_voltage_protection = REG_I2C_1_OVP1; + if (of_property_read_bool(node, "mps,overvoltage-protection-13v")) + pdata->over_voltage_protection = 0x00; + if (of_property_read_bool(node, "mps,overvoltage-protection-24v")) + pdata->over_voltage_protection = REG_I2C_1_OVP0; + if (of_property_read_bool(node, "mps,overvoltage-protection-35v")) + pdata->over_voltage_protection = REG_I2C_1_OVP1; + + return 0; +} + +static int mp3309c_enable_device(struct mp3309c_chip *chip) +{ + u8 reg_val = 0; /* Configuration for analog by I2C commands */ + int ret; + + /* I2C register #0 - Device enable */ + ret = regmap_update_bits(chip->regmap, REG_I2C_0, REG_I2C_0_EN, + REG_I2C_0_EN); + if (ret) + return ret; + + /* + * I2C register #1 - Set working mode: + * - set one of the two dimming mode: + * - PWM dimming using an external PWM dimming signal + * - analog dimming using I2C commands + * - enable synchronous mode (fixed for now) + * - set overvoltage protection (OVP) + */ + if (chip->pdata->dimming_mode == DIMMING_PWM) + reg_val = REG_I2C_1_DIMS; + ret = regmap_write(chip->regmap, REG_I2C_1, reg_val | REG_I2C_1_SYNC | + chip->pdata->over_voltage_protection); + if (ret) + return ret; + + return 0; +} + +/* For delayed backlight enabled */ +static void mp3309c_enable(struct work_struct *work) +{ + struct mp3309c_chip *chip = container_of(work, struct mp3309c_chip, + enable_work.work); + if (mp3309c_enable_device(chip)) + dev_err(chip->dev, "failed writing I2C register\n"); +} + +static void mp3309c_reset_gpio(struct work_struct *work) +{ + struct mp3309c_chip *chip = container_of(work, struct mp3309c_chip, + reset_gpio_work.work); + + if (chip->reset_gpio) { + gpiod_set_value_cansleep(chip->reset_gpio, 0); + usleep_range(100, 150); + gpiod_set_value_cansleep(chip->reset_gpio, 1); + usleep_range(chip->pdata->reset_on_length_ms * 1000, + (chip->pdata->reset_on_length_ms * 1000) + 100); + gpiod_set_value_cansleep(chip->reset_gpio, 0); + } +} + +static int mp3309c_bl_update_status(struct backlight_device *bl) +{ + struct mp3309c_chip *chip = bl_get_data(bl); + int brightness = backlight_get_brightness(bl); + struct pwm_state pwmstate; + unsigned int analog_val, bits_val; + int i, ret; + + if (chip->pdata->dimming_mode == DIMMING_PWM) { + /* + * PWM dimming mode + */ + pwm_init_state(chip->pwmd, &pwmstate); + pwm_set_relative_duty_cycle(&pwmstate, brightness, + chip->pdata->max_brightness); + pwmstate.enabled = true; + ret = pwm_apply_state(chip->pwmd, &pwmstate); + if (ret) + return ret; + } else { + /* + * Analog dimming mode by I2C commands + * + * The 5 bits of the dimming analog value D4..D0 is allocated + * in the I2C register #0, in the following way: + * + * +--+--+--+--+--+--+--+--+ + * |EN|D0|D1|D2|D3|D4|XX|XX| + * +--+--+--+--+--+--+--+--+ + */ + analog_val = DIV_ROUND_UP(ANALOG_MAX_VAL * brightness, + chip->pdata->max_brightness); + bits_val = 0; + for (i = 0; i <= 5; i++) + bits_val += ((analog_val >> i) & 0x01) << (6 - i); + ret = regmap_update_bits(chip->regmap, REG_I2C_0, + ANALOG_REG_MASK, bits_val); + if (ret) + return ret; + } + + if (brightness > 0) { + switch (chip->pdata->status) { + case FIRST_POWER_ON: + /* + * Only for the first time, wait for the optional + * switch-on delay and then enable the device. + * Otherwise enable the backlight immediately. + */ + schedule_delayed_work(&chip->enable_work, + msecs_to_jiffies(chip->pdata->switch_on_delay_ms)); + /* + * Optional external device GPIO reset, with + * delay pulse length + */ + if (chip->pdata->reset_pulse_enable) + schedule_delayed_work(&chip->reset_gpio_work, + msecs_to_jiffies(chip->pdata->reset_on_delay_ms)); + break; + case BACKLIGHT_OFF: + /* Enable the backlight immediately */ + if (chip->pdata->reset_pulse_enable) + cancel_delayed_work(&chip->reset_gpio_work); + mp3309c_enable_device(chip); + break; + } + + chip->pdata->status = BACKLIGHT_ON; + } else { + /* Wait for the optional switch-off delay */ + if (chip->pdata->switch_off_delay_ms > 0) { + usleep_range(chip->pdata->switch_off_delay_ms * 1000, + (chip->pdata->switch_off_delay_ms + 1) * + 1000); + } + + chip->pdata->status = BACKLIGHT_OFF; + } + + return 0; +} + +static const struct backlight_ops mp3309c_bl_ops = { + .update_status = mp3309c_bl_update_status, +}; + +static int mp3309c_probe(struct i2c_client *client) +{ + struct mp3309c_platform_data *pdata = dev_get_platdata(&client->dev); + struct mp3309c_chip *chip; + struct backlight_properties props; + int ret; + + if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) { + dev_err(&client->dev, "failed to check i2c functionality\n"); + return -EOPNOTSUPP; + } + + chip = devm_kzalloc(&client->dev, sizeof(struct mp3309c_chip), + GFP_KERNEL); + if (!chip) + return -ENOMEM; + chip->dev = &client->dev; + + chip->regmap = devm_regmap_init_i2c(client, &mp3309c_regmap); + if (IS_ERR(chip->regmap)) { + ret = PTR_ERR(chip->regmap); + dev_err(&client->dev, "failed to allocate register map\n"); + return ret; + } + + i2c_set_clientdata(client, chip); + + if (!pdata) { + pdata = devm_kzalloc(chip->dev, + sizeof(struct mp3309c_platform_data), + GFP_KERNEL); + if (!pdata) + return -ENOMEM; + + ret = pm3309c_parse_dt_node(chip, pdata); + if (ret) { + dev_err(&client->dev, "failed parsing DT node\n"); + return ret; + } + } + chip->pdata = pdata; + + chip->enable_gpio = devm_gpiod_get_optional(&client->dev, "enable", + GPIOD_OUT_HIGH); + if (IS_ERR(chip->enable_gpio)) { + ret = PTR_ERR(chip->enable_gpio); + return ret; + } + + /* Backlight */ + props.type = BACKLIGHT_RAW; + props.brightness = pdata->brightness; + props.max_brightness = pdata->max_brightness; + props.scale = BACKLIGHT_SCALE_LINEAR; + chip->bl = + devm_backlight_device_register(chip->dev, "mp3309c_bl", + chip->dev, chip, &mp3309c_bl_ops, + &props); + if (IS_ERR(chip->bl)) { + dev_err(&client->dev, "failed registering backlight\n"); + return PTR_ERR(chip->bl); + } + pdata->status = FIRST_POWER_ON; + + /* Enable PWM, if required */ + if (pdata->dimming_mode == DIMMING_PWM) { + chip->pwmd = devm_pwm_get(chip->dev, NULL); + if (IS_ERR(chip->pwmd)) { + dev_err(&client->dev, "failed getting pwm device\n"); + return PTR_ERR(chip->pwmd); + } + pwm_apply_args(chip->pwmd); + } + + /* + * Workqueue for delayed backlight enabling + */ + INIT_DELAYED_WORK(&chip->enable_work, mp3309c_enable); + + /* + * Workqueue for (optional) external device GPIO reset + */ + if (pdata->reset_pulse_enable) { + dev_info(&client->dev, "reset pulse enabled\n"); + INIT_DELAYED_WORK(&chip->reset_gpio_work, mp3309c_reset_gpio); + } + + dev_info(&client->dev, "MP3309C backlight initialized"); + return 0; +} + +static int mp3309c_backlight_switch_off(struct pwm_device *pwmd) +{ + struct pwm_state pwmstate; + + /* Switch-off the backlight */ + pwm_get_state(pwmd, &pwmstate); + pwmstate.duty_cycle = 0; + pwmstate.enabled = false; + pwm_apply_state(pwmd, &pwmstate); + + return 0; +} + +static void mp3309c_remove(struct i2c_client *client) +{ + struct mp3309c_chip *chip = i2c_get_clientdata(client); + + if (chip->pdata->dimming_mode == DIMMING_PWM) + mp3309c_backlight_switch_off(chip->pwmd); + if (chip->pdata->reset_pulse_enable) + cancel_delayed_work(&chip->reset_gpio_work); +} + +static void mp3309c_shutdown(struct i2c_client *client) +{ + struct mp3309c_chip *chip = i2c_get_clientdata(client); + + if (chip->pdata->dimming_mode == DIMMING_PWM) + mp3309c_backlight_switch_off(chip->pwmd); +} + +static const struct of_device_id mp3309c_match_table[] = { + { .compatible = "mps,mp3309c-backlight", }, + { }, +}; +MODULE_DEVICE_TABLE(of, mp3309c_match_table); + +static const struct i2c_device_id mp3309c_id[] = { + { "mp3309c", 0 }, + { } +}; +MODULE_DEVICE_TABLE(i2c, mp3309c_id); + +static struct i2c_driver mp3309c_i2c_driver = { + .driver = { + .name = "mp3309c-backlight", + .of_match_table = mp3309c_match_table, + }, + .probe = mp3309c_probe, + .remove = mp3309c_remove, + .shutdown = mp3309c_shutdown, + .id_table = mp3309c_id, +}; + +module_i2c_driver(mp3309c_i2c_driver); + +MODULE_DESCRIPTION("Backlight Driver for MPS MP3309C"); +MODULE_AUTHOR("Flavio Suligoi <f.suligoi@asem.it>"); +MODULE_LICENSE("GPL");
The Monolithic Power (MPS) MP3309C is a WLED step-up converter, featuring a programmable switching frequency to optimize efficiency. The brightness can be controlled either by I2C commands (called "analog" mode) or by a PWM input signal (PWM mode). This driver supports both modes. For DT configuration details, please refer to: - Documentation/devicetree/bindings/leds/backlight/mps,mp3309c.yaml The datasheet is available at: - https://www.monolithicpower.com/en/mp3309c.html Signed-off-by: Flavio Suligoi <f.suligoi@asem.it> --- MAINTAINERS | 6 + drivers/video/backlight/Kconfig | 13 + drivers/video/backlight/Makefile | 1 + drivers/video/backlight/mp3309c_bl.c | 491 +++++++++++++++++++++++++++ 4 files changed, 511 insertions(+) create mode 100644 drivers/video/backlight/mp3309c_bl.c