Message-ID: <20230928144230.GL9999@google.com>
Date:   Thu, 28 Sep 2023 15:42:30 +0100
From:   Lee Jones <lee@...nel.org>
To:     André Apitzsch <git@...tzsch.eu>
Cc:     Pavel Machek <pavel@....cz>, Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Conor Dooley <conor+dt@...nel.org>, linux-leds@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        phone-devel@...r.kernel.org, ~postmarketos/upstreaming@...ts.sr.ht,
        Uwe Kleine-König 
        <u.kleine-koenig@...gutronix.de>
Subject: Re: [PATCH v4 2/2] leds: add ktd202x driver

On Sat, 23 Sep 2023, André Apitzsch wrote:

> This commit adds support for Kinetic KTD2026/7 RGB/White LED driver.
> 
> Signed-off-by: André Apitzsch <git@...tzsch.eu>
> ---
>  drivers/leds/rgb/Kconfig        |  13 +
>  drivers/leds/rgb/Makefile       |   1 +
>  drivers/leds/rgb/leds-ktd202x.c | 625 ++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 639 insertions(+)
> 
> diff --git a/drivers/leds/rgb/Kconfig b/drivers/leds/rgb/Kconfig
> index 183bccc06cf3..a6a21f564673 100644
> --- a/drivers/leds/rgb/Kconfig
> +++ b/drivers/leds/rgb/Kconfig
> @@ -14,6 +14,19 @@ config LEDS_GROUP_MULTICOLOR
>  	  To compile this driver as a module, choose M here: the module
>  	  will be called leds-group-multicolor.
>  
> +config LEDS_KTD202X
> +	tristate "LED support for KTD202x Chips"
> +	depends on I2C
> +	depends on OF
> +	select REGMAP_I2C
> +	help
> +	  This option enables support for the Kinetic KTD2026/KTD2027
> +	  RGB/White LED driver found in different BQ mobile phones.
> +	  It is a 3 or 4 channel LED driver programmed via an I2C interface.
> +
> +	  To compile this driver as a module, choose M here: the module
> +	  will be called leds-ktd202x.
> +
>  config LEDS_PWM_MULTICOLOR
>  	tristate "PWM driven multi-color LED Support"
>  	depends on PWM
> diff --git a/drivers/leds/rgb/Makefile b/drivers/leds/rgb/Makefile
> index c11cc56384e7..243f31e4d70d 100644
> --- a/drivers/leds/rgb/Makefile
> +++ b/drivers/leds/rgb/Makefile
> @@ -1,6 +1,7 @@
>  # SPDX-License-Identifier: GPL-2.0
>  
>  obj-$(CONFIG_LEDS_GROUP_MULTICOLOR)	+= leds-group-multicolor.o
> +obj-$(CONFIG_LEDS_KTD202X)		+= leds-ktd202x.o
>  obj-$(CONFIG_LEDS_PWM_MULTICOLOR)	+= leds-pwm-multicolor.o
>  obj-$(CONFIG_LEDS_QCOM_LPG)		+= leds-qcom-lpg.o
>  obj-$(CONFIG_LEDS_MT6370_RGB)		+= leds-mt6370-rgb.o
> diff --git a/drivers/leds/rgb/leds-ktd202x.c b/drivers/leds/rgb/leds-ktd202x.c
> new file mode 100644
> index 000000000000..b328ecd34664
> --- /dev/null
> +++ b/drivers/leds/rgb/leds-ktd202x.c
> @@ -0,0 +1,625 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Kinetic KTD2026/7 RGB/White LED driver with I2C interface
> + *
> + * Copyright 2023 André Apitzsch <git@...tzsch.eu>
> + *
> + * Datasheet: https://www.kinet-ic.com/uploads/KTD2026-7-04h.pdf
> + */
> +
> +#include <linux/i2c.h>
> +#include <linux/led-class-multicolor.h>
> +#include <linux/module.h>
> +#include <linux/mutex.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>
> +#include <linux/regmap.h>
> +#include <linux/regulator/consumer.h>
> +
> +#define KTD2026_NUM_LEDS 3
> +#define KTD2027_NUM_LEDS 4
> +#define KTD202X_MAX_LEDS 4
> +
> +/* Register bank */
> +#define KTD202X_REG_RESET_CONTROL	0x00
> +#define KTD202X_REG_FLASH_PERIOD	0x01
> +#define KTD202X_REG_PWM1_TIMER		0x02
> +#define KTD202X_REG_PWM2_TIMER		0x03
> +#define KTD202X_REG_CHANNEL_CTRL	0x04
> +#define KTD202X_REG_TRISE_FALL		0x05
> +#define KTD202X_REG_LED_IOUT(x)		(0x06 + (x))
> +
> +/* Register 0 */
> +#define KTD202X_TIMER_SLOT_CONTROL_TSLOT1	0x00
> +#define KTD202X_TIMER_SLOT_CONTROL_TSLOT2	0x01
> +#define KTD202X_TIMER_SLOT_CONTROL_TSLOT3	0x02
> +#define KTD202X_TIMER_SLOT_CONTROL_TSLOT4	0x03
> +#define KTD202X_RSTR_RESET			0x07
> +
> +#define KTD202X_ENABLE_CTRL_WAKE	0x00 /* SCL High & SDA High */
> +#define KTD202X_ENABLE_CTRL_SLEEP	0x08 /* SCL High & SDA Toggling */
> +
> +#define KTD202X_TRISE_FALL_SCALE_NORMAL		0x00
> +#define KTD202X_TRISE_FALL_SCALE_SLOW_X2	0x20
> +#define KTD202X_TRISE_FALL_SCALE_SLOW_X4	0x40
> +#define KTD202X_TRISE_FALL_SCALE_FAST_X8	0x60
> +
> +/* Register 1 */
> +#define KTD202X_FLASH_PERIOD_256_MS_LOG_RAMP	0x00
> +
> +/* Register 2-3 */
> +#define KTD202X_FLASH_ON_TIME_0_4_PERCENT	0x01
> +
> +/* Register 4 */
> +#define KTD202X_CHANNEL_CTRL_MASK(x) (BIT(2 * (x)) | BIT(2 * (x) + 1))
> +#define KTD202X_CHANNEL_CTRL_OFF 0x00
> +#define KTD202X_CHANNEL_CTRL_ON(x) BIT(2 * (x))
> +#define KTD202X_CHANNEL_CTRL_PWM1(x) BIT(2 * (x) + 1)
> +#define KTD202X_CHANNEL_CTRL_PWM2(x) (BIT(2 * (x)) | BIT(2 * (x) + 1))
> +
> +/* Register 5 */
> +#define KTD202X_RAMP_TIMES_2_MS			0x00
> +
> +/* Register 6-9 */
> +#define KTD202X_LED_CURRENT_10_mA		0x4f
> +
> +#define KTD202X_FLASH_PERIOD_MIN_MS 256
> +#define KTD202X_FLASH_PERIOD_STEP_MS 128
> +#define KTD202X_FLASH_PERIOD_MAX_STEPS 126
> +#define KTD202X_FLASH_ON_MAX 256
> +
> +#define KTD202X_MAX_BRIGHTNESS 192
> +
> +static const struct reg_default ktd202x_reg_defaults[] = {
> +	{ KTD202X_REG_RESET_CONTROL, KTD202X_TIMER_SLOT_CONTROL_TSLOT1 |
> +		KTD202X_ENABLE_CTRL_WAKE | KTD202X_TRISE_FALL_SCALE_NORMAL },
> +	{ KTD202X_REG_FLASH_PERIOD, KTD202X_FLASH_PERIOD_256_MS_LOG_RAMP },
> +	{ KTD202X_REG_PWM1_TIMER, KTD202X_FLASH_ON_TIME_0_4_PERCENT },
> +	{ KTD202X_REG_PWM2_TIMER, KTD202X_FLASH_ON_TIME_0_4_PERCENT },
> +	{ KTD202X_REG_CHANNEL_CTRL, KTD202X_CHANNEL_CTRL_OFF },
> +	{ KTD202X_REG_TRISE_FALL, KTD202X_RAMP_TIMES_2_MS },
> +	{ KTD202X_REG_LED_IOUT(0), KTD202X_LED_CURRENT_10_mA },
> +	{ KTD202X_REG_LED_IOUT(1), KTD202X_LED_CURRENT_10_mA },
> +	{ KTD202X_REG_LED_IOUT(2), KTD202X_LED_CURRENT_10_mA },
> +	{ KTD202X_REG_LED_IOUT(3), KTD202X_LED_CURRENT_10_mA },
> +};
> +
> +struct ktd202x_led {
> +	struct ktd202x *chip;
> +	union {
> +		struct led_classdev cdev;
> +		struct led_classdev_mc mcdev;
> +	};
> +	u32 index;
> +};
> +
> +struct ktd202x {
> +	struct mutex mutex;
> +	struct regulator_bulk_data regulators[2];
> +	struct device *dev;
> +	struct regmap *regmap;
> +	bool enabled;
> +	int num_leds;
> +	struct ktd202x_led leds[] __counted_by(num_leds);
> +};
> +
> +static int ktd202x_chip_disable(struct ktd202x *chip)
> +{
> +	int ret;
> +
> +	if (!chip->enabled)
> +		return 0;
> +
> +	regmap_write(chip->regmap, KTD202X_REG_RESET_CONTROL,
> +		     KTD202X_ENABLE_CTRL_SLEEP);
> +
> +	ret = regulator_bulk_disable(ARRAY_SIZE(chip->regulators),
> +				     chip->regulators);
> +	if (ret) {
> +		dev_err(chip->dev, "Failed to disable regulators: %d\n", ret);
> +		return ret;
> +	}
> +
> +	chip->enabled = false;
> +	return 0;
> +}
> +
> +static int ktd202x_chip_enable(struct ktd202x *chip)
> +{
> +	int ret;
> +
> +	if (chip->enabled)
> +		return 0;
> +
> +	ret = regulator_bulk_enable(ARRAY_SIZE(chip->regulators),
> +				    chip->regulators);
> +	if (ret) {
> +		dev_err(chip->dev, "Failed to enable regulators: %d\n", ret);
> +		return ret;
> +	}
> +	chip->enabled = true;
> +
> +	ret = regmap_write(chip->regmap, KTD202X_REG_RESET_CONTROL,
> +			   KTD202X_ENABLE_CTRL_WAKE);
> +
> +	if (ret) {
> +		dev_err(chip->dev, "Failed to enable the chip: %d\n", ret);
> +		ktd202x_chip_disable(chip);
> +	}
> +
> +	return ret;
> +}
> +
> +static bool ktd202x_chip_in_use(struct ktd202x *chip)
> +{
> +	int i;
> +
> +	for (i = 0; i < chip->num_leds; i++) {
> +		if (chip->leds[i].cdev.brightness)
> +			return true;
> +	}

Nit: '\n' here.

> +	return false;
> +}
> +
> +static int ktd202x_brightness_set(struct ktd202x_led *led,
> +				  struct mc_subled *subleds,
> +				  unsigned int num_channels)
> +{
> +	enum led_brightness brightness;
> +	bool mode_blink;
> +	int common_mode;
> +	int channel;
> +	int state;
> +	int mode;
> +	int ret;
> +	int i;

This makes me happy! :)

> +	if (ktd202x_chip_in_use(led->chip)) {
> +		ret = ktd202x_chip_enable(led->chip);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	ret = regmap_read(led->chip->regmap, KTD202X_REG_CHANNEL_CTRL, &state);
> +	if (ret)
> +		return ret;
> +
> +	for (i = 0; i < num_channels; i++) {
> +		channel = subleds[i].channel;
> +		common_mode |= (state >> 2*channel) & (BIT(0) | BIT(1));

Nit: There should be spaces around the '*'.

This whole line needs a comment really.

Please define the BIT() macros: SOMETHING_SOMETHING_MASK

> +	}
> +	mode_blink = common_mode == KTD202X_CHANNEL_CTRL_PWM1(0);

Make is really easy for us - comment please.

  Assume blink mode since PWM is set to ... etc

> +	for (i = 0; i < num_channels; i++) {
> +		brightness = subleds[i].brightness;
> +		channel = subleds[i].channel;
> +
> +		ret = regmap_write(led->chip->regmap,
> +				   KTD202X_REG_LED_IOUT(channel),
> +				   brightness ? brightness-1 : 0);

Comment please. Why the -1?

Spaces around the '-'.

> +		if (ret)
> +			return ret;
> +
> +		if (brightness) {
> +			if (mode_blink)
> +				mode = KTD202X_CHANNEL_CTRL_PWM1(channel);
> +			else
> +				mode = KTD202X_CHANNEL_CTRL_ON(channel);
> +		} else {
> +			mode = KTD202X_CHANNEL_CTRL_OFF;
> +		}
> +		ret = regmap_update_bits(led->chip->regmap,
> +					 KTD202X_REG_CHANNEL_CTRL,
> +					 KTD202X_CHANNEL_CTRL_MASK(channel),
> +					 mode);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	if (!ktd202x_chip_in_use(led->chip))
> +		return ktd202x_chip_disable(led->chip);
> +
> +	return 0;
> +}
> +
> +static int ktd202x_brightness_single_set(struct led_classdev *cdev,
> +					 enum led_brightness value)
> +{
> +	struct ktd202x_led *led = container_of(cdev, struct ktd202x_led, cdev);
> +	struct mc_subled info;
> +	int ret;
> +
> +	cdev->brightness = value;
> +
> +	mutex_lock(&led->chip->mutex);
> +
> +	info.brightness = value;
> +	info.channel = led->index;
> +	ret = ktd202x_brightness_set(led, &info, 1);
> +
> +	mutex_unlock(&led->chip->mutex);
> +
> +	return ret;
> +}
> +
> +static int ktd202x_brightness_mc_set(struct led_classdev *cdev,
> +				     enum led_brightness value)
> +{
> +	struct led_classdev_mc *mc = lcdev_to_mccdev(cdev);
> +	struct ktd202x_led *led = container_of(mc, struct ktd202x_led, mcdev);
> +	int ret;
> +
> +	cdev->brightness = value;
> +
> +	mutex_lock(&led->chip->mutex);
> +
> +	led_mc_calc_color_components(mc, value);
> +	ret = ktd202x_brightness_set(led, mc->subled_info, mc->num_colors);
> +
> +	mutex_unlock(&led->chip->mutex);
> +
> +	return ret;
> +}
> +
> +static int ktd202x_blink_set(struct ktd202x_led *led, unsigned long *delay_on,
> +			     unsigned long *delay_off, struct mc_subled *subleds,
> +			     unsigned int num_channels)
> +{
> +	unsigned long delay_total_ms;
> +	int ret, num_steps, on;
> +	u8 ctrl_mask = 0;
> +	u8 ctrl_pwm1 = 0;
> +	u8 ctrl_on = 0;
> +	int i, channel;
> +
> +	mutex_lock(&led->chip->mutex);
> +
> +	for (i = 0; i < num_channels; i++) {
> +		channel = subleds[i].channel;
> +		ctrl_mask |= KTD202X_CHANNEL_CTRL_MASK(channel);
> +		ctrl_on |= KTD202X_CHANNEL_CTRL_ON(channel);
> +		ctrl_pwm1 |= KTD202X_CHANNEL_CTRL_PWM1(channel);
> +	}
> +
> +	/* Never off - brightness is already set, disable blinking */
> +	if (!*delay_off) {
> +		ret = regmap_update_bits(led->chip->regmap,
> +					 KTD202X_REG_CHANNEL_CTRL,
> +					 ctrl_mask,
> +					 ctrl_on);
> +		goto out;
> +	}
> +
> +	/* Convert into values the HW will understand. */

I'm guessing this describes the whole chunk?

If so, '\n' here - if not, merge it with the one below and turn it into
a multi-line comment.

> +	/* Integer representation of time of flash period */
> +	num_steps = (*delay_on + *delay_off - KTD202X_FLASH_PERIOD_MIN_MS) /
> +		    KTD202X_FLASH_PERIOD_STEP_MS;
> +	num_steps = clamp(num_steps, 0, KTD202X_FLASH_PERIOD_MAX_STEPS);

'\n' - lay it out to make is easy on the reader.

> +	/* Integer representation of percentage of LED ON time */
> +	on = (*delay_on * KTD202X_FLASH_ON_MAX) / (*delay_on + *delay_off);
> +
> +	/* Actually used delay_{on,off} values */
> +	delay_total_ms = num_steps * KTD202X_FLASH_PERIOD_STEP_MS +
> +			 KTD202X_FLASH_PERIOD_MIN_MS;
> +	*delay_on = (delay_total_ms * on) / KTD202X_FLASH_ON_MAX;
> +	*delay_off = delay_total_ms - *delay_on;
> +
> +	/* Set timings */
> +	ret = regmap_write(led->chip->regmap, KTD202X_REG_FLASH_PERIOD,
> +			   num_steps);
> +	if (ret)
> +		goto out;
> +
> +	ret = regmap_write(led->chip->regmap, KTD202X_REG_PWM1_TIMER, on);
> +	if (ret)
> +		goto out;
> +
> +	ret = regmap_update_bits(led->chip->regmap, KTD202X_REG_CHANNEL_CTRL,
> +				 ctrl_mask,
> +				 ctrl_pwm1);
> +out:
> +	mutex_unlock(&led->chip->mutex);
> +	return ret;
> +}
> +
> +static int ktd202x_blink_single_set(struct led_classdev *cdev,
> +				    unsigned long *delay_on,
> +				    unsigned long *delay_off)
> +{
> +	struct ktd202x_led *led = container_of(cdev, struct ktd202x_led, cdev);
> +	struct mc_subled info;
> +	int ret;
> +
> +	if (!cdev->brightness) {
> +		ret = ktd202x_brightness_single_set(cdev, KTD202X_MAX_BRIGHTNESS);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	/* If no blink specified, default to 1 Hz. */
> +	if (!*delay_off && !*delay_on) {
> +		*delay_off = 500;
> +		*delay_on = 500;
> +	}
> +
> +	/* Never on - just set to off */
> +	if (!*delay_on)
> +		return ktd202x_brightness_single_set(cdev, LED_OFF);
> +
> +	info.channel = led->index;
> +
> +	return ktd202x_blink_set(led, delay_on, delay_off, &info, 1);
> +}
> +
> +static int ktd202x_blink_mc_set(struct led_classdev *cdev,
> +				unsigned long *delay_on,
> +				unsigned long *delay_off)
> +{
> +	struct led_classdev_mc *mc = lcdev_to_mccdev(cdev);
> +	struct ktd202x_led *led = container_of(mc, struct ktd202x_led, mcdev);
> +	int ret;
> +
> +	if (!cdev->brightness) {
> +		ret = ktd202x_brightness_mc_set(cdev, KTD202X_MAX_BRIGHTNESS);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	/* If no blink specified, default to 1 Hz. */
> +	if (!*delay_off && !*delay_on) {
> +		*delay_off = 500;
> +		*delay_on = 500;
> +	}
> +
> +	/* Never on - just set to off */
> +	if (!*delay_on)
> +		return ktd202x_brightness_mc_set(cdev, LED_OFF);
> +
> +	return ktd202x_blink_set(led, delay_on, delay_off, mc->subled_info,
> +				 mc->num_colors);
> +}
> +
> +static int ktd202x_add_led(struct ktd202x *chip, struct device_node *np,
> +			   unsigned int index)
> +{
> +	struct ktd202x_led *led = &chip->leds[index];
> +	struct led_init_data init_data = {};
> +	struct led_classdev *cdev;
> +	struct device_node *child;
> +	struct mc_subled *info;
> +	int num_channels;
> +	u32 color = 0;
> +	u32 reg;
> +	int ret;
> +	int i;
> +
> +	/* Color property is optional in single color case */
> +	ret = of_property_read_u32(np, "color", &color);
> +	if (ret < 0 && ret != -EINVAL) {
> +		dev_err(chip->dev, "failed to parse 'color' of %pOF\n", np);
> +		return ret;
> +	}
> +
> +	if (color == LED_COLOR_ID_RGB) {
> +		num_channels = of_get_available_child_count(np);
> +		if (!num_channels || num_channels > chip->num_leds)
> +			return -EINVAL;
> +	} else {
> +		num_channels = 1;
> +	}
> +
> +	led->chip = chip;
> +
> +	if (color == LED_COLOR_ID_RGB) {
> +		info = devm_kcalloc(chip->dev, num_channels, sizeof(*info),
> +				    GFP_KERNEL);
> +		if (!info)
> +			return -ENOMEM;
> +
> +		i = 0;
> +		for_each_available_child_of_node(np, child) {
> +			u32 mono_color = 0;
> +
> +			ret = of_property_read_u32(child, "reg", &reg);
> +			if (ret != 0 || reg >= chip->num_leds) {
> +				dev_err(chip->dev, "invalid 'reg' of %pOFn\n",
> +					np);

There are a lot of little line-wraps in this file.

I would open them out and set your new max-chars 80 -> 100.

Much easier on the eye.

> +				return -EINVAL;
> +			}
> +
> +			ret = of_property_read_u32(child, "color", &mono_color);
> +			if (ret < 0 && ret != -EINVAL) {
> +				dev_err(chip->dev,
> +					"failed to parse 'color' of %pOF\n",
> +					np);
> +				return ret;
> +			}
> +
> +			info[i].color_index = mono_color;
> +			info[i].channel = reg;
> +			info[i].intensity = 0;
> +			i++;
> +		}
> +
> +		led->mcdev.subled_info = info;
> +		led->mcdev.num_colors = num_channels;
> +
> +		cdev = &led->mcdev.led_cdev;
> +		cdev->brightness_set_blocking = ktd202x_brightness_mc_set;
> +		cdev->blink_set = ktd202x_blink_mc_set;

Maybe these need to be in their own functions:

ktd202x_setup_led_rgb()
ktd202x_setup_led_single()

?

> +	} else {
> +		ret = of_property_read_u32(np, "reg", &reg);
> +		if (ret != 0 || reg >= chip->num_leds) {
> +			dev_err(chip->dev, "invalid 'reg' of %pOFn\n", np);
> +			return -EINVAL;
> +		}
> +		led->index = reg;
> +
> +		cdev = &led->cdev;
> +		cdev->brightness_set_blocking = ktd202x_brightness_single_set;
> +		cdev->blink_set = ktd202x_blink_single_set;
> +	}
> +
> +	cdev->max_brightness = KTD202X_MAX_BRIGHTNESS;
> +
> +	init_data.fwnode = of_fwnode_handle(np);

Do this before calling the above new functions.

> +	if (color == LED_COLOR_ID_RGB)

... then put these into the functions.

> +		ret = devm_led_classdev_multicolor_register_ext(chip->dev,
> +								&led->mcdev,
> +								&init_data);
> +	else
> +		ret = devm_led_classdev_register_ext(chip->dev, &led->cdev,
> +						     &init_data);
> +	if (ret) {
> +		dev_err(chip->dev, "unable to register %s\n", cdev->name);
> +		of_node_put(np);
> +	}
> +
> +	return ret;
> +}
> +
> +static int ktd202x_probe_dt(struct ktd202x *chip)
> +{
> +	struct device_node *np = dev_of_node(chip->dev), *child;
> +	unsigned int i;
> +	int count, ret;
> +
> +	chip->num_leds = (int)(unsigned long)of_device_get_match_data(chip->dev);

There are a bunch of recent patches converting these to:

  i2c_get_match_data()

... is that also applicable here?

> +	count = of_get_available_child_count(np);
> +	if (!count || count > chip->num_leds)
> +		return -EINVAL;
> +
> +	regmap_write(chip->regmap, KTD202X_REG_RESET_CONTROL,
> +		     KTD202X_RSTR_RESET);
> +
> +	/* Allow the device to execute the complete reset */
> +	usleep_range(200, 300);
> +
> +	i = 0;
> +	for_each_available_child_of_node(np, child) {
> +		ret = ktd202x_add_led(chip, child, i);
> +		if (ret)
> +			return ret;
> +		i++;
> +	}
> +
> +	return 0;
> +}
> +
> +static const struct regmap_config ktd202x_regmap_config = {
> +	.reg_bits = 8,
> +	.val_bits = 8,
> +	.max_register = 0x09,
> +	.cache_type = REGCACHE_FLAT,
> +	.reg_defaults = ktd202x_reg_defaults,
> +	.num_reg_defaults = ARRAY_SIZE(ktd202x_reg_defaults),
> +};
> +
> +static int ktd202x_probe(struct i2c_client *client)
> +{
> +	struct device *dev = &client->dev;
> +	struct ktd202x *chip;
> +	int count;
> +	int ret;
> +
> +	count = device_get_child_node_count(dev);
> +	if (!count || count > KTD202X_MAX_LEDS)
> +		return dev_err_probe(dev, -EINVAL,
> +				     "Incorrect number of leds (%d)", count);
> +
> +	chip = devm_kzalloc(dev, struct_size(chip, leds, count), GFP_KERNEL);
> +	if (!chip)
> +		return -ENOMEM;
> +
> +	mutex_init(&chip->mutex);
> +
> +	chip->dev = dev;
> +	i2c_set_clientdata(client, chip);
> +
> +	chip->regmap = devm_regmap_init_i2c(client, &ktd202x_regmap_config);
> +	if (IS_ERR(chip->regmap)) {
> +		ret = dev_err_probe(dev, PTR_ERR(chip->regmap),
> +				    "Failed to allocate register map.\n");
> +		goto error;

Where is the mutex first used?

I'd suggest moving mutex_init() as late as possible and omitting as many
of these gotos as you can.

> +	}
> +
> +	chip->regulators[0].supply = "vin";
> +	chip->regulators[1].supply = "vio";
> +	ret = devm_regulator_bulk_get(dev, ARRAY_SIZE(chip->regulators),
> +				      chip->regulators);
> +	if (ret < 0) {
> +		dev_err_probe(dev, ret, "Failed to request regulators.\n");
> +		goto error;
> +	}
> +
> +	ret = regulator_bulk_enable(ARRAY_SIZE(chip->regulators),
> +				    chip->regulators);
> +	if (ret) {
> +		dev_err_probe(dev, ret, "Failed to enable regulators.\n");
> +		goto error;
> +	}
> +
> +	ret = ktd202x_probe_dt(chip);
> +	if (ret < 0)
> +		goto error_reg;
> +
> +	ret = regulator_bulk_disable(ARRAY_SIZE(chip->regulators),
> +				     chip->regulators);
> +	if (ret) {
> +		dev_err_probe(dev, ret, "Failed to disable regulators.\n");
> +		goto error;
> +	}
> +
> +	return 0;
> +
> +error_reg:
> +	regulator_bulk_disable(ARRAY_SIZE(chip->regulators),
> +			       chip->regulators);
> +
> +error:
> +	mutex_destroy(&chip->mutex);
> +	return ret;
> +}
> +
> +static void ktd202x_remove(struct i2c_client *client)
> +{
> +	struct ktd202x *chip = i2c_get_clientdata(client);
> +
> +	ktd202x_chip_disable(chip);
> +
> +	mutex_destroy(&chip->mutex);
> +}
> +
> +static void ktd202x_shutdown(struct i2c_client *client)
> +{
> +	struct ktd202x *chip = i2c_get_clientdata(client);
> +
> +	/* Reset registers to make sure all off before shutdown */

Grammar.

> +	regmap_write(chip->regmap, KTD202X_REG_RESET_CONTROL,
> +		     KTD202X_RSTR_RESET);
> +}
> +
> +static const struct of_device_id ktd202x_match_table[] = {
> +	{ .compatible = "kinetic,ktd2026", .data = (void *)KTD2026_NUM_LEDS },
> +	{ .compatible = "kinetic,ktd2027", .data = (void *)KTD2027_NUM_LEDS },
> +	{},
> +};
> +

Remove these line.

> +MODULE_DEVICE_TABLE(of, ktd202x_match_table);
> +
> +static struct i2c_driver ktd202x_driver = {
> +	.driver = {
> +		.name = "leds-ktd202x",
> +		.of_match_table = ktd202x_match_table,
> +	},
> +	.probe = ktd202x_probe,
> +	.remove = ktd202x_remove,
> +	.shutdown = ktd202x_shutdown,
> +};
> +module_i2c_driver(ktd202x_driver);
> +
> +MODULE_AUTHOR("André Apitzsch <git@...tzsch.eu>");
> +MODULE_DESCRIPTION("Kinetic KTD2026/7 LED driver");
> +MODULE_LICENSE("GPL");
> 
> -- 
> 2.42.0
> 

-- 
8)
3)
Lee Jones [李琼斯]

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