Re: [PATCH v17 RESEND 2/3] leds: flash: mt6370: Add MediaTek MT6370 flashlight support

[Lee Jones]

On Thu, 23 Feb 2023, ChiaEn Wu wrote:

> From: ChiYuan Huang <cy_huang@xxxxxxxxxxx>
> 
> The MediaTek MT6370 is a highly-integrated smart power management IC,
> which includes a single cell Li-Ion/Li-Polymer switching battery
> charger, a USB Type-C & Power Delivery (PD) controller, dual Flash
> LED current sources, a RGB LED driver, a backlight WLED driver,
> a display bias driver and a general LDO for portable devices.
> 
> Add support for the MT6370 Flash LED driver. Flash LED in MT6370
> has 2 channels and support torch/strobe mode.
> 
> Acked-by: Jacek Anaszewski <jacek.anaszewski@xxxxxxxxx>
> Co-developed-by: Alice Chen <alice_chen@xxxxxxxxxxx>
> Signed-off-by: Alice Chen <alice_chen@xxxxxxxxxxx>
> Signed-off-by: ChiYuan Huang <cy_huang@xxxxxxxxxxx>
> Signed-off-by: ChiaEn Wu <chiaen_wu@xxxxxxxxxxx>
> ---
> v17
> - Update the year of Copyright from 2022 to 2023
> 
> ---
>  drivers/leds/flash/Kconfig             |  13 +
>  drivers/leds/flash/Makefile            |   1 +
>  drivers/leds/flash/leds-mt6370-flash.c | 596 +++++++++++++++++++++++++++++++++
>  3 files changed, 610 insertions(+)
>  create mode 100644 drivers/leds/flash/leds-mt6370-flash.c

Please unwrap to 100-chars throughout.
 
> diff --git a/drivers/leds/flash/Kconfig b/drivers/leds/flash/Kconfig
> index d3eb689..49d8922 100644
> --- a/drivers/leds/flash/Kconfig
> +++ b/drivers/leds/flash/Kconfig
> @@ -61,6 +61,19 @@ config LEDS_MT6360
>  	  Independent current sources supply for each flash LED support torch
>  	  and strobe mode.
>  
> +config LEDS_MT6370_FLASH
> +	tristate "Flash LED Support for MediaTek MT6370 PMIC"
> +	depends on LEDS_CLASS
> +	depends on V4L2_FLASH_LED_CLASS || !V4L2_FLASH_LED_CLASS
> +	depends on MFD_MT6370
> +	help
> +	  Support 2 channels and torch/strobe mode.
> +	  Say Y here to enable support for
> +	  MT6370_FLASH_LED device.
> +
> +	  This driver can also be built as a module. If so, the module
> +	  will be called "leds-mt6370-flash".
> +
>  config LEDS_RT4505
>  	tristate "LED support for RT4505 flashlight controller"
>  	depends on I2C && OF
> diff --git a/drivers/leds/flash/Makefile b/drivers/leds/flash/Makefile
> index 0acbddc..4665e8e 100644
> --- a/drivers/leds/flash/Makefile
> +++ b/drivers/leds/flash/Makefile
> @@ -1,6 +1,7 @@
>  # SPDX-License-Identifier: GPL-2.0
>  
>  obj-$(CONFIG_LEDS_MT6360)	+= leds-mt6360.o
> +obj-$(CONFIG_LEDS_MT6370_FLASH)	+= leds-mt6370-flash.o
>  obj-$(CONFIG_LEDS_AAT1290)	+= leds-aat1290.o
>  obj-$(CONFIG_LEDS_AS3645A)	+= leds-as3645a.o
>  obj-$(CONFIG_LEDS_KTD2692)	+= leds-ktd2692.o
> diff --git a/drivers/leds/flash/leds-mt6370-flash.c b/drivers/leds/flash/leds-mt6370-flash.c
> new file mode 100644
> index 00000000..b03617f
> --- /dev/null
> +++ b/drivers/leds/flash/leds-mt6370-flash.c
> @@ -0,0 +1,596 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (C) 2023 Richtek Technology Corp.
> + *
> + * Authors:
> + *   Alice Chen <alice_chen@xxxxxxxxxxx>
> + *   ChiYuan Huang <cy_huang@xxxxxxxxxxx>
> + */
> +
> +#include <linux/bitops.h>
> +#include <linux/delay.h>
> +#include <linux/init.h>
> +#include <linux/interrupt.h>
> +#include <linux/kernel.h>
> +#include <linux/led-class-flash.h>
> +#include <linux/module.h>
> +#include <linux/mutex.h>
> +#include <linux/platform_device.h>
> +#include <linux/property.h>
> +#include <linux/regmap.h>
> +
> +#include <media/v4l2-flash-led-class.h>
> +
> +enum {
> +	MT6370_LED_FLASH1 = 0,
> +	MT6370_LED_FLASH2,
> +	MT6370_MAX_LEDS
> +};
> +
> +/* Virtual definition for multicolor */
> +
> +#define MT6370_REG_FLEDEN		0x17E
> +#define MT6370_REG_STRBTO		0x173
> +#define MT6370_REG_CHGSTAT2		0x1D1
> +#define MT6370_REG_FLEDSTAT1		0x1D9
> +#define MT6370_REG_FLEDISTRB(_id)	(0x174 + 4 * (_id))
> +#define MT6370_REG_FLEDITOR(_id)	(0x175 + 4 * (_id))
> +#define MT6370_ITORCH_MASK		GENMASK(4, 0)
> +#define MT6370_ISTROBE_MASK		GENMASK(6, 0)
> +#define MT6370_STRBTO_MASK		GENMASK(6, 0)
> +#define MT6370_TORCHEN_MASK		BIT(3)
> +#define MT6370_STROBEN_MASK		BIT(2)
> +#define MT6370_FLCSEN_MASK(_id)		BIT(MT6370_LED_FLASH2 - (_id))
> +#define MT6370_FLCSEN_MASK_ALL		GENMASK(1, 0)
> +#define MT6370_FLEDCHGVINOVP_MASK	BIT(3)
> +#define MT6370_FLED1STRBTO_MASK		BIT(11)
> +#define MT6370_FLED2STRBTO_MASK		BIT(10)
> +#define MT6370_FLED1STRB_MASK		BIT(9)
> +#define MT6370_FLED2STRB_MASK		BIT(8)
> +#define MT6370_FLED1SHORT_MASK		BIT(7)
> +#define MT6370_FLED2SHORT_MASK		BIT(6)
> +#define MT6370_FLEDLVF_MASK		BIT(3)
> +
> +#define MT6370_LED_JOINT		2
> +#define MT6370_RANGE_FLED_REG		4
> +#define MT6370_ITORCH_MIN_uA		25000
> +#define MT6370_ITORCH_STEP_uA		12500
> +#define MT6370_ITORCH_MAX_uA		400000
> +#define MT6370_ITORCH_DOUBLE_MAX_uA	800000
> +#define MT6370_ISTRB_MIN_uA		50000
> +#define MT6370_ISTRB_STEP_uA		12500
> +#define MT6370_ISTRB_MAX_uA		1500000
> +#define MT6370_ISTRB_DOUBLE_MAX_uA	3000000
> +#define MT6370_STRBTO_MIN_US		64000
> +#define MT6370_STRBTO_STEP_US		32000
> +#define MT6370_STRBTO_MAX_US		2432000
> +
> +#define to_mt6370_led(ptr, member) container_of(ptr, struct mt6370_led, member)
> +
> +struct mt6370_led {
> +	struct led_classdev_flash flash;
> +	struct v4l2_flash *v4l2_flash;
> +	struct mt6370_priv *priv;
> +	u8 led_no;
> +};
> +
> +struct mt6370_priv {
> +	struct regmap *regmap;
> +	struct mutex lock;
> +	unsigned int fled_strobe_used;
> +	unsigned int fled_torch_used;
> +	unsigned int leds_active;
> +	unsigned int leds_count;
> +	struct mt6370_led leds[];
> +};
> +
> +static int mt6370_torch_brightness_set(struct led_classdev *lcdev,
> +				       enum led_brightness level)
> +{
> +	struct mt6370_led *led = to_mt6370_led(lcdev, flash.led_cdev);
> +	struct mt6370_priv *priv = led->priv;
> +	u32 led_enable_mask = led->led_no == MT6370_LED_JOINT ?
> +			      MT6370_FLCSEN_MASK_ALL :
> +			      MT6370_FLCSEN_MASK(led->led_no);
> +	u32 enable_mask = MT6370_TORCHEN_MASK | led_enable_mask;
> +	u32 val = level ? led_enable_mask : 0;
> +	u32 curr;
> +	int ret, i;
> +
> +	mutex_lock(&priv->lock);
> +
> +	/*
> +	 * There is only one set of flash control logic, and this
> +	 * flag is used to check if 'strobe' is currently being used.
> +	 */
> +	if (priv->fled_strobe_used) {
> +		dev_warn(lcdev->dev, "Please disable strobe first [%d]\n",
> +			 priv->fled_strobe_used);
> +		ret = -EBUSY;
> +		goto unlock;
> +	}
> +
> +	if (level)
> +		curr = priv->fled_torch_used | BIT(led->led_no);
> +	else
> +		curr = priv->fled_torch_used & ~BIT(led->led_no);
> +
> +	if (curr)
> +		val |= MT6370_TORCHEN_MASK;
> +
> +	if (level) {
> +		level -= 1;
> +		if (led->led_no == MT6370_LED_JOINT) {
> +			u32 flevel[MT6370_MAX_LEDS];
> +
> +			flevel[0] = level / 2;
> +			flevel[1] = level - flevel[0];
> +			for (i = 0; i < MT6370_MAX_LEDS; i++) {
> +				ret = regmap_update_bits(priv->regmap,
> +						MT6370_REG_FLEDITOR(i),
> +						MT6370_ITORCH_MASK, flevel[i]);
> +				if (ret)
> +					goto unlock;
> +			}
> +		} else {
> +			ret = regmap_update_bits(priv->regmap,
> +					MT6370_REG_FLEDITOR(led->led_no),
> +					MT6370_ITORCH_MASK, level);
> +			if (ret)
> +				goto unlock;
> +		}
> +	}
> +
> +	ret = regmap_update_bits(priv->regmap, MT6370_REG_FLEDEN,
> +				 enable_mask, val);
> +	if (ret)
> +		goto unlock;
> +
> +	priv->fled_torch_used = curr;
> +
> +unlock:
> +	mutex_unlock(&priv->lock);
> +	return ret;
> +}
> +
> +static int mt6370_flash_brightness_set(struct led_classdev_flash *fl_cdev,
> +				       u32 brightness)
> +{
> +	/*
> +	 * Because of the current spikes when turning on the flash,
> +	 * the brightness should be kept by the LED framework. This
> +	 * empty function is used to prevent checking failure when
> +	 * led_classdev_flash registers ops.
> +	 */
> +	return 0;
> +}
> +
> +static int _mt6370_flash_brightness_set(struct led_classdev_flash *fl_cdev,
> +					u32 brightness)
> +{
> +	struct mt6370_led *led = to_mt6370_led(fl_cdev, flash);
> +	struct mt6370_priv *priv = led->priv;
> +	struct led_flash_setting *setting = &fl_cdev->brightness;
> +	u32 val = (brightness - setting->min) / setting->step;
> +	int ret, i;
> +
> +	if (led->led_no == MT6370_LED_JOINT) {

What is a "JOINT"?

> +		u32 flevel[MT6370_MAX_LEDS];
> +
> +		flevel[0] = val / 2;
> +		flevel[1] = val - flevel[0];

Please provide a comment describing what's going on here.

> +		for (i = 0; i < MT6370_MAX_LEDS; i++) {
> +			ret = regmap_update_bits(priv->regmap,
> +						 MT6370_REG_FLEDISTRB(i),
> +						 MT6370_ISTROBE_MASK, flevel[i]);
> +			if (ret)
> +				break;
> +		}
> +	} else
> +		ret = regmap_update_bits(priv->regmap,
> +					 MT6370_REG_FLEDISTRB(led->led_no),
> +					 MT6370_ISTROBE_MASK, val);
> +
> +	return ret;
> +}
> +
> +static int mt6370_strobe_set(struct led_classdev_flash *fl_cdev, bool state)
> +{
> +	struct mt6370_led *led = to_mt6370_led(fl_cdev, flash);
> +	struct mt6370_priv *priv = led->priv;
> +	struct led_classdev *lcdev = &fl_cdev->led_cdev;
> +	struct led_flash_setting *s = &fl_cdev->brightness;
> +	u32 led_enable_mask = led->led_no == MT6370_LED_JOINT ?
> +			      MT6370_FLCSEN_MASK_ALL :
> +			      MT6370_FLCSEN_MASK(led->led_no);
> +	u32 enable_mask = MT6370_STROBEN_MASK | led_enable_mask;
> +	u32 val = state ? led_enable_mask : 0;
> +	u32 curr;
> +	int ret;
> +
> +	mutex_lock(&priv->lock);
> +
> +	/*
> +	 * There is only one set of flash control logic, and this
> +	 * flag is used to check if 'torch' is currently being used.
> +	 */
> +	if (priv->fled_torch_used) {
> +		dev_warn(lcdev->dev, "Please disable torch first [0x%x]\n",
> +				      priv->fled_torch_used);
> +		ret = -EBUSY;
> +		goto unlock;
> +	}
> +
> +	if (state)
> +		curr = priv->fled_strobe_used | BIT(led->led_no);
> +	else
> +		curr = priv->fled_strobe_used & ~BIT(led->led_no);
> +
> +	if (curr)
> +		val |= MT6370_STROBEN_MASK;
> +
> +	ret = regmap_update_bits(priv->regmap, MT6370_REG_FLEDEN, enable_mask,
> +				 val);
> +	if (ret) {
> +		dev_err(lcdev->dev, "[%d] control current source %d fail\n",
> +				     led->led_no, state);
> +		goto unlock;
> +	}
> +
> +	/*
> +	 * If the flash needs to turn on, configure the flash current to
> +	 * ramp up to the setting value. Otherwise, always revert to the
> +	 * minimum one.
> +	 */
> +	ret = _mt6370_flash_brightness_set(fl_cdev, state ? s->val : s->min);
> +	if (ret) {
> +		dev_err(lcdev->dev, "[%d] Failed to set brightness\n", led->led_no);
> +		goto unlock;
> +	}
> +
> +	/*
> +	 * For the flash to turn on/off, we must wait for HW ramping
> +	 * up/down time 5ms/500us to prevent the unexpected problem.
> +	 */
> +	if (!priv->fled_strobe_used && curr)
> +		usleep_range(5000, 6000);
> +	else if (priv->fled_strobe_used && !curr)
> +		usleep_range(500, 600);
> +
> +	priv->fled_strobe_used = curr;
> +
> +unlock:
> +	mutex_unlock(&priv->lock);
> +	return ret;
> +}
> +
> +static int mt6370_strobe_get(struct led_classdev_flash *fl_cdev, bool *state)
> +{
> +	struct mt6370_led *led = to_mt6370_led(fl_cdev, flash);
> +	struct mt6370_priv *priv = led->priv;
> +
> +	mutex_lock(&priv->lock);
> +	*state = !!(priv->fled_strobe_used & BIT(led->led_no));
> +	mutex_unlock(&priv->lock);
> +
> +	return 0;
> +}
> +
> +static int mt6370_timeout_set(struct led_classdev_flash *fl_cdev, u32 timeout)
> +{
> +	struct mt6370_led *led = to_mt6370_led(fl_cdev, flash);
> +	struct mt6370_priv *priv = led->priv;
> +	struct led_flash_setting *s = &fl_cdev->timeout;
> +	u32 val = (timeout - s->min) / s->step;
> +
> +	return regmap_update_bits(priv->regmap, MT6370_REG_STRBTO,
> +				  MT6370_STRBTO_MASK, val);
> +}
> +
> +static int mt6370_fault_get(struct led_classdev_flash *fl_cdev, u32 *fault)
> +{
> +	struct mt6370_led *led = to_mt6370_led(fl_cdev, flash);
> +	struct mt6370_priv *priv = led->priv;
> +	u16 fled_stat;
> +	unsigned int chg_stat, strobe_timeout_mask, fled_short_mask;
> +	u32 rfault = 0;
> +	int ret;
> +
> +	ret = regmap_read(priv->regmap, MT6370_REG_CHGSTAT2, &chg_stat);
> +	if (ret)
> +		return ret;
> +
> +	ret = regmap_raw_read(priv->regmap, MT6370_REG_FLEDSTAT1, &fled_stat,
> +			      sizeof(fled_stat));
> +	if (ret)
> +		return ret;
> +
> +	switch (led->led_no) {
> +	case MT6370_LED_FLASH1:
> +		strobe_timeout_mask = MT6370_FLED1STRBTO_MASK;
> +		fled_short_mask = MT6370_FLED1SHORT_MASK;
> +		break;
> +
> +	case MT6370_LED_FLASH2:
> +		strobe_timeout_mask = MT6370_FLED2STRBTO_MASK;
> +		fled_short_mask = MT6370_FLED2SHORT_MASK;
> +		break;
> +
> +	case MT6370_LED_JOINT:
> +		strobe_timeout_mask = MT6370_FLED1STRBTO_MASK |
> +				      MT6370_FLED2STRBTO_MASK;
> +		fled_short_mask = MT6370_FLED1SHORT_MASK |
> +				  MT6370_FLED2SHORT_MASK;
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	if (chg_stat & MT6370_FLEDCHGVINOVP_MASK)
> +		rfault |= LED_FAULT_INPUT_VOLTAGE;
> +
> +	if (fled_stat & strobe_timeout_mask)
> +		rfault |= LED_FAULT_TIMEOUT;
> +
> +	if (fled_stat & fled_short_mask)
> +		rfault |= LED_FAULT_SHORT_CIRCUIT;
> +
> +	if (fled_stat & MT6370_FLEDLVF_MASK)
> +		rfault |= LED_FAULT_UNDER_VOLTAGE;
> +
> +	*fault = rfault;
> +	return ret;
> +}
> +
> +static const struct led_flash_ops mt6370_flash_ops = {
> +	.flash_brightness_set = mt6370_flash_brightness_set,
> +	.strobe_set = mt6370_strobe_set,
> +	.strobe_get = mt6370_strobe_get,
> +	.timeout_set = mt6370_timeout_set,
> +	.fault_get = mt6370_fault_get,
> +};
> +
> +#if IS_ENABLED(CONFIG_V4L2_FLASH_LED_CLASS)
> +static int mt6370_flash_external_strobe_set(struct v4l2_flash *v4l2_flash,
> +					    bool enable)
> +{
> +	struct led_classdev_flash *flash = v4l2_flash->fled_cdev;
> +	struct mt6370_led *led = to_mt6370_led(flash, flash);
> +	struct mt6370_priv *priv = led->priv;
> +	u32 mask = led->led_no == MT6370_LED_JOINT ? MT6370_FLCSEN_MASK_ALL :
> +		   MT6370_FLCSEN_MASK(led->led_no);
> +	u32 val = enable ? mask : 0;
> +	int ret;
> +
> +	mutex_lock(&priv->lock);
> +
> +	ret = regmap_update_bits(priv->regmap, MT6370_REG_FLEDEN, mask, val);
> +	if (ret)
> +		goto unlock;
> +
> +	if (enable)
> +		priv->fled_strobe_used |= BIT(led->led_no);
> +	else
> +		priv->fled_strobe_used &= ~BIT(led->led_no);
> +
> +unlock:
> +	mutex_unlock(&priv->lock);
> +	return ret;
> +}
> +
> +static const struct v4l2_flash_ops v4l2_flash_ops = {
> +	.external_strobe_set = mt6370_flash_external_strobe_set,
> +};
> +
> +static void mt6370_init_v4l2_flash_config(struct mt6370_led *led,
> +					  struct v4l2_flash_config *cfg)
> +{
> +	struct led_classdev *lcdev;
> +	struct led_flash_setting *s = &cfg->intensity;
> +
> +	lcdev = &led->flash.led_cdev;
> +
> +	s->min = MT6370_ITORCH_MIN_uA;
> +	s->step = MT6370_ITORCH_STEP_uA;
> +	s->val = s->max = s->min + (lcdev->max_brightness - 1) * s->step;
> +
> +	cfg->has_external_strobe = 1;

has_external_strobe is a bool.

> +	strscpy(cfg->dev_name, dev_name(lcdev->dev), sizeof(cfg->dev_name));
> +
> +	cfg->flash_faults = LED_FAULT_SHORT_CIRCUIT | LED_FAULT_TIMEOUT |
> +			    LED_FAULT_INPUT_VOLTAGE | LED_FAULT_UNDER_VOLTAGE;
> +}
> +#else
> +static const struct v4l2_flash_ops v4l2_flash_ops;
> +static void mt6370_init_v4l2_flash_config(struct mt6370_led *led,
> +					  struct v4l2_flash_config *cfg)
> +{
> +}
> +#endif
> +
> +static void mt6370_v4l2_flash_release(void *v4l2_flash)
> +{
> +	v4l2_flash_release(v4l2_flash);
> +}
> +
> +static int mt6370_led_register(struct device *parent, struct mt6370_led *led,
> +				struct fwnode_handle *fwnode)
> +{
> +	struct led_init_data init_data = { .fwnode = fwnode };
> +	struct v4l2_flash_config v4l2_config = {};
> +	int ret;
> +
> +	ret = devm_led_classdev_flash_register_ext(parent, &led->flash,
> +						   &init_data);
> +	if (ret)
> +		return dev_err_probe(parent, ret,
> +				     "Couldn't register flash %d\n", led->led_no);
> +
> +	mt6370_init_v4l2_flash_config(led, &v4l2_config);
> +	led->v4l2_flash = v4l2_flash_init(parent, fwnode, &led->flash,
> +					  &v4l2_flash_ops, &v4l2_config);
> +	if (IS_ERR(led->v4l2_flash))
> +		return dev_err_probe(parent, PTR_ERR(led->v4l2_flash),
> +				     "Failed to register %d v4l2 sd\n", led->led_no);
> +
> +	return devm_add_action_or_reset(parent, mt6370_v4l2_flash_release,
> +					led->v4l2_flash);
> +}
> +
> +static u32 mt6370_clamp(u32 val, u32 min, u32 max, u32 step)
> +{
> +	u32 retval;
> +
> +	retval = clamp_val(val, min, max);
> +	if (step > 1)
> +		retval = rounddown(retval - min, step) + min;
> +
> +	return retval;
> +}
> +
> +static int mt6370_init_flash_properties(struct device *dev,
> +					struct mt6370_led *led,
> +					struct fwnode_handle *fwnode)
> +{
> +	struct led_classdev_flash *flash = &led->flash;
> +	struct led_classdev *lcdev = &flash->led_cdev;
> +	struct mt6370_priv *priv = led->priv;
> +	struct led_flash_setting *s;
> +	u32 sources[MT6370_MAX_LEDS];
> +	u32 max_ua, val;
> +	int i, ret, num;
> +
> +	num = fwnode_property_count_u32(fwnode, "led-sources");
> +	if (num < 1)
> +		return dev_err_probe(dev, -EINVAL,
> +				     "Not specified or wrong number of led-sources\n");
> +
> +	ret = fwnode_property_read_u32_array(fwnode, "led-sources", sources, num);
> +	if (ret)
> +		return ret;
> +
> +	for (i = 0; i < num; i++) {
> +		if (sources[i] >= MT6370_MAX_LEDS)
> +			return -EINVAL;
> +		if (priv->leds_active & BIT(sources[i]))
> +			return -EINVAL;
> +		priv->leds_active |= BIT(sources[i]);
> +	}
> +
> +	led->led_no = num == 2 ? MT6370_LED_JOINT : sources[0];
> +
> +	max_ua = num == 2 ? MT6370_ITORCH_DOUBLE_MAX_uA : MT6370_ITORCH_MAX_uA;
> +	val = MT6370_ITORCH_MIN_uA;

In what scenario does this not get overwritten?

> +	ret = fwnode_property_read_u32(fwnode, "led-max-microamp", &val);
> +	if (!ret)
> +		val = mt6370_clamp(val, MT6370_ITORCH_MIN_uA, max_ua,
> +				   MT6370_ITORCH_STEP_uA);
> +
> +	lcdev->max_brightness = (val - MT6370_ITORCH_MIN_uA) /
> +				 MT6370_ITORCH_STEP_uA + 1;
> +	lcdev->brightness_set_blocking = mt6370_torch_brightness_set;
> +	lcdev->flags |= LED_DEV_CAP_FLASH;
> +
> +	max_ua = num == 2 ? MT6370_ISTRB_DOUBLE_MAX_uA : MT6370_ISTRB_MAX_uA;
> +	val = MT6370_ISTRB_MIN_uA;
> +	ret = fwnode_property_read_u32(fwnode, "flash-max-microamp", &val);
> +	if (!ret)
> +		val = mt6370_clamp(val, MT6370_ISTRB_MIN_uA, max_ua,
> +				   MT6370_ISTRB_STEP_uA);
> +
> +	s = &flash->brightness;
> +	s->min = MT6370_ISTRB_MIN_uA;
> +	s->step = MT6370_ISTRB_STEP_uA;
> +	s->val = s->max = val;
> +
> +	/*
> +	 * Always configure to the minimum level when
> +	 * off to prevent flash current spikes.
> +	 */
> +	ret = _mt6370_flash_brightness_set(flash, s->min);
> +	if (ret)
> +		return ret;
> +
> +
> +	val = MT6370_STRBTO_MIN_US;

As above.

> +	ret = fwnode_property_read_u32(fwnode, "flash-max-timeout-us", &val);
> +	if (!ret)
> +		val = mt6370_clamp(val, MT6370_STRBTO_MIN_US,
> +				   MT6370_STRBTO_MAX_US, MT6370_STRBTO_STEP_US);
> +
> +	s = &flash->timeout;
> +	s->min = MT6370_STRBTO_MIN_US;
> +	s->step = MT6370_STRBTO_STEP_US;
> +	s->val = s->max = val;
> +
> +	flash->ops = &mt6370_flash_ops;
> +
> +	return 0;
> +}
> +
> +static int mt6370_led_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct mt6370_priv *priv;
> +	struct fwnode_handle *child;
> +	size_t count;
> +	int i = 0, ret;
> +
> +	count = device_get_child_node_count(dev);
> +	if (!count || count > MT6370_MAX_LEDS)
> +		return dev_err_probe(dev, -EINVAL,
> +		       "No child node or node count over max led number %zu\n", count);
> +
> +	priv = devm_kzalloc(dev, struct_size(priv, leds, count), GFP_KERNEL);
> +	if (!priv)
> +		return -ENOMEM;
> +
> +	priv->leds_count = count;
> +	mutex_init(&priv->lock);
> +
> +	priv->regmap = dev_get_regmap(dev->parent, NULL);
> +	if (!priv->regmap)
> +		return dev_err_probe(dev, -ENODEV, "Failed to get parent regmap\n");
> +
> +	device_for_each_child_node(dev, child) {
> +		struct mt6370_led *led = priv->leds + i;
> +
> +		led->priv = priv;
> +
> +		ret = mt6370_init_flash_properties(dev, led, child);
> +		if (ret) {
> +			fwnode_handle_put(child);
> +			return ret;
> +		}
> +
> +		ret = mt6370_led_register(dev, led, child);
> +		if (ret) {
> +			fwnode_handle_put(child);
> +			return ret;
> +		}
> +
> +		i++;
> +	}
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id mt6370_led_of_id[] = {
> +	{ .compatible = "mediatek,mt6370-flashlight" },
> +	{ /* sentinel */ }

Please remove this comment.  We know how NULL terminators work. :)

> +};
> +MODULE_DEVICE_TABLE(of, mt6370_led_of_id);
> +
> +static struct platform_driver mt6370_led_driver = {
> +	.driver = {
> +		.name = "mt6370-flashlight",
> +		.of_match_table = mt6370_led_of_id,
> +	},
> +	.probe = mt6370_led_probe,
> +};
> +module_platform_driver(mt6370_led_driver);
> +
> +MODULE_AUTHOR("Alice Chen <alice_chen@xxxxxxxxxxx>");
> +MODULE_AUTHOR("ChiYuan Huang <cy_huang@xxxxxxxxxxx>");
> +MODULE_DESCRIPTION("MT6370 FLASH LED Driver");
> +MODULE_LICENSE("GPL");
> -- 
> 2.7.4
> 

-- 
Lee Jones [李琼斯]