Message-ID: <20250501110306.GF1567507@google.com>
Date: Thu, 1 May 2025 12:03:06 +0100
From: Lee Jones <lee@...nel.org>
To: Matthias Fend <matthias.fend@...end.at>
Cc: Pavel Machek <pavel@....cz>, Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>, Pavel Machek <pavel@...nel.org>,
	linux-leds@...r.kernel.org, devicetree@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	bsp-development.geo@...ca-geosystems.com
Subject: Re: [PATCH v3 2/2] leds: tps6131x: add support for Texas Instruments
 TPS6131X flash LED driver

On Wed, 23 Apr 2025, Matthias Fend wrote:

> The TPS61310/TPS61311 is a flash LED driver with I2C interface. Its power
> stage is capable of supplying a maximum total current of roughly 1500mA.
> The TPS6131x provides three constant-current sinks, capable of sinking up
> to 2 × 400mA (LED1 and LED3) and 800mA (LED2) in flash mode. In torch mode
> each sink (LED1, LED2, LED3) supports currents up to 175mA.
> 
> Signed-off-by: Matthias Fend <matthias.fend@...end.at>
> ---
>  MAINTAINERS                        |   7 +
>  drivers/leds/flash/Kconfig         |  11 +
>  drivers/leds/flash/Makefile        |   1 +
>  drivers/leds/flash/leds-tps6131x.c | 798 +++++++++++++++++++++++++++++++++++++
>  4 files changed, 817 insertions(+)

Looks pretty good in general.  Just a few nits, really.

> diff --git a/MAINTAINERS b/MAINTAINERS
> index fa1e04e87d1d63c1b01b59744d7ade00fe5a1885..67e7c165efd332dfe3bc5ec64a4cc10845d7bbd6 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -23983,6 +23983,13 @@ F:	Documentation/devicetree/bindings/hwmon/ti,tps23861.yaml
>  F:	Documentation/hwmon/tps23861.rst
>  F:	drivers/hwmon/tps23861.c
>  
> +TEXAS INSTRUMENTS TPS6131X FLASH LED DRIVER
> +M:	Matthias Fend <matthias.fend@...end.at>
> +L:	linux-leds@...r.kernel.org
> +S:	Maintained
> +F:	Documentation/devicetree/bindings/leds/ti,tps6131x.yaml
> +F:	drivers/leds/flash/leds-tps6131x.c
> +
>  TEXAS INSTRUMENTS' DAC7612 DAC DRIVER
>  M:	Ricardo Ribalda <ribalda@...nel.org>
>  L:	linux-iio@...r.kernel.org
> diff --git a/drivers/leds/flash/Kconfig b/drivers/leds/flash/Kconfig
> index f39f0bfe6eefcd376405d9d35dc36e323a485002..55ca663ca506ad8be627f58f6d6308368ea2b928 100644
> --- a/drivers/leds/flash/Kconfig
> +++ b/drivers/leds/flash/Kconfig
> @@ -132,4 +132,15 @@ config LEDS_SY7802
>  
>  	  This driver can be built as a module, it will be called "leds-sy7802".
>  
> +config LEDS_TPS6131X
> +	tristate "LED support for TI TPS6131x flash LED driver"
> +	depends on I2C && OF
> +	depends on GPIOLIB
> +	select REGMAP_I2C
> +	help
> +	  This option enables support for Texas Instruments TPS61310/TPS61311
> +	  flash LED driver.
> +
> +	  This driver can be built as a module, it will be called "leds-tps6131x".
> +
>  endif # LEDS_CLASS_FLASH
> diff --git a/drivers/leds/flash/Makefile b/drivers/leds/flash/Makefile
> index 48860eeced79513a0ed303e4af3db9bfe9724b7e..712fb737a428e42747e1aa339058dc4306ade9c8 100644
> --- a/drivers/leds/flash/Makefile
> +++ b/drivers/leds/flash/Makefile
> @@ -12,3 +12,4 @@ obj-$(CONFIG_LEDS_RT4505)	+= leds-rt4505.o
>  obj-$(CONFIG_LEDS_RT8515)	+= leds-rt8515.o
>  obj-$(CONFIG_LEDS_SGM3140)	+= leds-sgm3140.o
>  obj-$(CONFIG_LEDS_SY7802)	+= leds-sy7802.o
> +obj-$(CONFIG_LEDS_TPS6131X)	+= leds-tps6131x.o
> diff --git a/drivers/leds/flash/leds-tps6131x.c b/drivers/leds/flash/leds-tps6131x.c
> new file mode 100644
> index 0000000000000000000000000000000000000000..c123fb3f908c865f8a9e60b0339067cdb5a864f6
> --- /dev/null
> +++ b/drivers/leds/flash/leds-tps6131x.c
> @@ -0,0 +1,798 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Texas Instruments TPS61310/TPS61311 flash LED driver with I2C interface
> + *
> + * Copyright 2025 Matthias Fend <matthias.fend@...end.at>
> + */
> +
> +#include <linux/gpio/consumer.h>
> +#include <linux/i2c.h>
> +#include <linux/led-class-flash.h>
> +#include <linux/leds.h>
> +#include <linux/module.h>
> +#include <linux/regmap.h>
> +#include <media/v4l2-flash-led-class.h>
> +
> +/* Registers */

This little header comments are superfluous IMHO.

The nomenclature of the defines is good enough.

> +#define TPS6131X_REG_0				0x00
> +#define TPS6131X_REG_0_RESET			BIT(7)

Suggest adding a space or two before the bit defines, like:

#define TPS6131X_REG_0                          0x00
#define   TPS6131X_REG_0_RESET                  BIT(7)

> +#define TPS6131X_REG_0_DCLC13			GENMASK(5, 3)
> +#define TPS6131X_REG_0_DCLC13_SHIFT		3
> +#define TPS6131X_REG_0_DCLC2			GENMASK(2, 0)
> +#define TPS6131X_REG_0_DCLC2_SHIFT		0
> +
> +#define TPS6131X_REG_1				0x01
> +#define TPS6131X_REG_1_MODE			GENMASK(7, 6)
> +#define TPS6131X_REG_1_MODE_SHIFT		6
> +#define TPS6131X_REG_1_FC2			GENMASK(5, 0)
> +#define TPS6131X_REG_1_FC2_SHIFT		0
> +
> +#define TPS6131X_REG_2				0x02
> +#define TPS6131X_REG_2_MODE			GENMASK(7, 6)
> +#define TPS6131X_REG_2_MODE_SHIFT		6
> +#define TPS6131X_REG_2_ENVM			BIT(5)
> +#define TPS6131X_REG_2_FC13			GENMASK(4, 0)
> +#define TPS6131X_REG_2_FC13_SHIFT		0
> +
> +#define TPS6131X_REG_3				0x03
> +#define TPS6131X_REG_3_STIM			GENMASK(7, 5)
> +#define TPS6131X_REG_3_STIM_SHIFT		5
> +#define TPS6131X_REG_3_HPFL			BIT(4)
> +#define TPS6131X_REG_3_SELSTIM_TO		BIT(3)
> +#define TPS6131X_REG_3_STT			BIT(2)
> +#define TPS6131X_REG_3_SFT			BIT(1)
> +#define TPS6131X_REG_3_TXMASK			BIT(0)
> +
> +#define TPS6131X_REG_4				0x04
> +#define TPS6131X_REG_4_PG			BIT(7)
> +#define TPS6131X_REG_4_HOTDIE_HI		BIT(6)
> +#define TPS6131X_REG_4_HOTDIE_LO		BIT(5)
> +#define TPS6131X_REG_4_ILIM			BIT(4)
> +#define TPS6131X_REG_4_INDC			GENMASK(3, 0)
> +#define TPS6131X_REG_4_INDC_SHIFT		0
> +
> +#define TPS6131X_REG_5				0x05
> +#define TPS6131X_REG_5_SELFCAL			BIT(7)
> +#define TPS6131X_REG_5_ENPSM			BIT(6)
> +#define TPS6131X_REG_5_STSTRB1_DIR		BIT(5)
> +#define TPS6131X_REG_5_GPIO			BIT(4)
> +#define TPS6131X_REG_5_GPIOTYPE			BIT(3)
> +#define TPS6131X_REG_5_ENLED3			BIT(2)
> +#define TPS6131X_REG_5_ENLED2			BIT(1)
> +#define TPS6131X_REG_5_ENLED1			BIT(0)
> +
> +#define TPS6131X_REG_6				0x06
> +#define TPS6131X_REG_6_ENTS			BIT(7)
> +#define TPS6131X_REG_6_LEDHOT			BIT(6)
> +#define TPS6131X_REG_6_LEDWARN			BIT(5)
> +#define TPS6131X_REG_6_LEDHDR			BIT(4)
> +#define TPS6131X_REG_6_OV			GENMASK(3, 0)
> +#define TPS6131X_REG_6_OV_SHIFT			0
> +
> +#define TPS6131X_REG_7				0x07
> +#define TPS6131X_REG_7_ENBATMON			BIT(7)
> +#define TPS6131X_REG_7_BATDROOP			GENMASK(6, 4)
> +#define TPS6131X_REG_7_BATDROOP_SHIFT		4
> +#define TPS6131X_REG_7_REVID			GENMASK(2, 0)
> +#define TPS6131X_REG_7_REVID_SHIFT		0
> +
> +/* Constants */
> +
> +#define TPS6131X_MAX_CHANNELS			3
> +
> +#define TPS6131X_FLASH_MAX_I_CHAN13_MA		400
> +#define TPS6131X_FLASH_MAX_I_CHAN2_MA		800
> +#define TPS6131X_FLASH_STEP_I_MA		25
> +
> +#define TPS6131X_TORCH_MAX_I_CHAN13_MA		175
> +#define TPS6131X_TORCH_MAX_I_CHAN2_MA		175
> +#define TPS6131X_TORCH_STEP_I_MA		25
> +
> +#define TPS6131X_TORCH_REFRESH_INTERVAL_JIFFIES msecs_to_jiffies(10000)

Why 10s?

> +#define UA_TO_MA(UA)				((UA) / 1000)

I'm surprised a generic macro like this doesn't exist already.

> +enum tps6131x_mode {
> +	TPS6131X_MODE_SHUTDOWN = 0x0,
> +	TPS6131X_MODE_TORCH = 0x1,
> +	TPS6131X_MODE_FLASH = 0x2,

Are these set in stone or are they arbitrary?

> +};
> +
> +struct tps6131x {
> +	struct device *dev;
> +	struct regmap *regmap;
> +	struct gpio_desc *reset_gpio;
> +	/*
> +	 * Registers 0, 1, 2, and 3 control parts of the controller that are not completely
> +	 * independent of each other. Since some operations require the registers to be written in
> +	 * a specific order to avoid unwanted side effects, they are synchronized with a lock.
> +	 */
> +	struct mutex lock; /* Hardware access lock for register 0, 1, 2 and 3 */
> +	struct delayed_work torch_refresh_work;
> +	bool valley_current_limit;
> +	bool chan1_en;
> +	bool chan2_en;
> +	bool chan3_en;
> +	struct fwnode_handle *led_node;
> +	u32 max_flash_current_ma;
> +	u32 step_flash_current_ma;
> +	u32 max_torch_current_ma;
> +	u32 step_torch_current_ma;
> +	u32 max_timeout_us;
> +	struct led_classdev_flash fled_cdev;
> +	struct v4l2_flash *v4l2_flash;
> +};
> +
> +static struct tps6131x *fled_cdev_to_tps6131x(struct led_classdev_flash *fled_cdev)
> +{
> +	return container_of(fled_cdev, struct tps6131x, fled_cdev);
> +}
> +
> +/*
> + * Register contents after a power on/reset. These values cannot be changed.
> + */
> +static const struct reg_default tps6131x_regmap_defaults[] = {
> +	{ TPS6131X_REG_0, (1 << TPS6131X_REG_0_DCLC13_SHIFT) | (2 << TPS6131X_REG_0_DCLC2_SHIFT) },

Real values should be defined.  What does 2 even do, etc?

> +	{ TPS6131X_REG_1, (0 << TPS6131X_REG_1_MODE_SHIFT) | (16 << TPS6131X_REG_1_FC2_SHIFT) },

What's the point in oring 0 values?  Can't you just omit them?

> +	{ TPS6131X_REG_2, (0 << TPS6131X_REG_2_MODE_SHIFT) | (8 << TPS6131X_REG_2_FC13_SHIFT) },
> +	{ TPS6131X_REG_3, (6 << TPS6131X_REG_3_STIM_SHIFT) | TPS6131X_REG_3_TXMASK },
> +	{ TPS6131X_REG_4, (0 << TPS6131X_REG_4_INDC_SHIFT) },
> +	{ TPS6131X_REG_5, TPS6131X_REG_5_ENPSM | TPS6131X_REG_5_STSTRB1_DIR |
> +				  TPS6131X_REG_5_GPIOTYPE | TPS6131X_REG_5_ENLED2 },
> +	{ TPS6131X_REG_6, (9 << TPS6131X_REG_6_OV_SHIFT) },
> +	{ TPS6131X_REG_7, (4 << TPS6131X_REG_7_BATDROOP_SHIFT) },
> +};
> +
> +/*
> + * These registers contain flags that are reset when read. Ensure that these registers are not read
> + * outside of a call from the driver.

You can simplify to just the first sentence.  The rest is implied.

> + */
> +static bool tps6131x_regmap_precious(struct device *dev, unsigned int reg)
> +{
> +	switch (reg) {
> +	case TPS6131X_REG_3:
> +	case TPS6131X_REG_4:
> +	case TPS6131X_REG_6:
> +		return true;
> +	default:
> +		return false;
> +	}
> +}
> +
> +static const struct regmap_config tps6131x_regmap = {
> +	.reg_bits = 8,
> +	.val_bits = 8,
> +	.max_register = TPS6131X_REG_7,
> +	.reg_defaults = tps6131x_regmap_defaults,
> +	.num_reg_defaults = ARRAY_SIZE(tps6131x_regmap_defaults),
> +	.cache_type = REGCACHE_FLAT,

This is new to me.  Why was this chosen over the usual REGCACHE_MAPLE?
> +	.precious_reg = &tps6131x_regmap_precious,
> +};
> +
> +struct tps6131x_timer_config {
> +	u8 val;
> +	u8 range;
> +	u32 time_us;
> +};
> +
> +static const struct tps6131x_timer_config tps6131x_timer_configs[] = {
> +	{ .val = 0, .range = 1, .time_us = 5300 },
> +	{ .val = 1, .range = 1, .time_us = 10700 },
> +	{ .val = 2, .range = 1, .time_us = 16000 },
> +	{ .val = 3, .range = 1, .time_us = 21300 },
> +	{ .val = 4, .range = 1, .time_us = 26600 },
> +	{ .val = 5, .range = 1, .time_us = 32000 },
> +	{ .val = 6, .range = 1, .time_us = 37300 },
> +	{ .val = 0, .range = 0, .time_us = 68200 },
> +	{ .val = 7, .range = 1, .time_us = 71500 },
> +	{ .val = 1, .range = 0, .time_us = 102200 },
> +	{ .val = 2, .range = 0, .time_us = 136300 },
> +	{ .val = 3, .range = 0, .time_us = 170400 },
> +	{ .val = 4, .range = 0, .time_us = 204500 },
> +	{ .val = 5, .range = 0, .time_us = 340800 },
> +	{ .val = 6, .range = 0, .time_us = 579300 },
> +	{ .val = 7, .range = 0, .time_us = 852000 },
> +};
> +
> +static const struct tps6131x_timer_config *tps6131x_find_closest_timer_config(u32 timeout_us)
> +{
> +	const struct tps6131x_timer_config *timer_config = &tps6131x_timer_configs[0];
> +	u32 diff, min_diff = U32_MAX;
> +	int i;
> +
> +	for (i = 0; i < ARRAY_SIZE(tps6131x_timer_configs); i++) {
> +		diff = abs(tps6131x_timer_configs[i].time_us - timeout_us);
> +		if (diff < min_diff) {
> +			timer_config = &tps6131x_timer_configs[i];
> +			min_diff = diff;
> +			if (!min_diff)
> +				break;
> +		}
> +	}
> +
> +	return timer_config;
> +}
> +
> +static int tps6131x_reset_chip(struct tps6131x *tps6131x)
> +{
> +	int ret;
> +
> +	if (tps6131x->reset_gpio) {
> +		gpiod_set_value_cansleep(tps6131x->reset_gpio, 1);
> +		fsleep(10);
> +		gpiod_set_value_cansleep(tps6131x->reset_gpio, 0);
> +		fsleep(100);
> +	} else {
> +		ret = regmap_update_bits(tps6131x->regmap, TPS6131X_REG_0, TPS6131X_REG_0_RESET,
> +					 TPS6131X_REG_0_RESET);
> +		if (ret)
> +			return ret;
> +
> +		fsleep(100);
> +
> +		ret = regmap_update_bits(tps6131x->regmap, TPS6131X_REG_0, TPS6131X_REG_0_RESET, 0);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static int tps6131x_init_chip(struct tps6131x *tps6131x)
> +{
> +	u32 reg4, reg5, reg6;

Why cant we just reuse a single variable called 'value'?

> +	int ret;
> +
> +	reg4 = tps6131x->valley_current_limit ? TPS6131X_REG_4_ILIM : 0;

Nicer on the eye if we un-squidge these.

No need to group everything like this.

> +	ret = regmap_write(tps6131x->regmap, TPS6131X_REG_4, reg4);
> +	if (ret)
> +		return ret;
> +
> +	reg5 = TPS6131X_REG_5_ENPSM | TPS6131X_REG_5_STSTRB1_DIR | TPS6131X_REG_5_GPIOTYPE;
> +	if (tps6131x->chan1_en)
> +		reg5 |= TPS6131X_REG_5_ENLED1;
> +
> +	if (tps6131x->chan2_en)
> +		reg5 |= TPS6131X_REG_5_ENLED2;
> +
> +	if (tps6131x->chan3_en)
> +		reg5 |= TPS6131X_REG_5_ENLED3;
> +	ret = regmap_write(tps6131x->regmap, TPS6131X_REG_5, reg5);
> +	if (ret)
> +		return ret;
> +
> +	reg6 = TPS6131X_REG_6_ENTS;
> +	ret = regmap_write(tps6131x->regmap, TPS6131X_REG_6, reg6);
> +	if (ret)
> +		return ret;
> +
> +	return 0;
> +}
> +
> +static int tps6131x_set_mode(struct tps6131x *tps6131x, enum tps6131x_mode mode, bool force)
> +{
> +	u8 val;
> +
> +	val = mode << TPS6131X_REG_1_MODE_SHIFT;

You could do this during assignment.  Or, seeing as there is already a
line break required, in the call itself.

> +
> +	return regmap_update_bits_base(tps6131x->regmap, TPS6131X_REG_1, TPS6131X_REG_1_MODE, val,
> +				       NULL, false, force);
> +}
> +
> +static void tps6131x_torch_refresh_handler(struct work_struct *work)
> +{
> +	struct tps6131x *tps6131x = container_of(work, struct tps6131x, torch_refresh_work.work);
> +
> +	guard(mutex)(&tps6131x->lock);
> +
> +	tps6131x_set_mode(tps6131x, TPS6131X_MODE_TORCH, true);

This can fail.

> +
> +	schedule_delayed_work(&tps6131x->torch_refresh_work,
> +			      TPS6131X_TORCH_REFRESH_INTERVAL_JIFFIES);
> +}
> +
> +static int tps6131x_brightness_set(struct led_classdev *cdev, enum led_brightness brightness)
> +{
> +	struct led_classdev_flash *fled_cdev = lcdev_to_flcdev(cdev);
> +	struct tps6131x *tps6131x = fled_cdev_to_tps6131x(fled_cdev);

> +	u32 num_chans;
> +	u32 steps_chan13, steps_chan2;
> +	u32 steps_remaining;

Why not group these?

> +	u8 reg0;
> +	int ret;
> +
> +	cancel_delayed_work_sync(&tps6131x->torch_refresh_work);
> +
> +	/*
> +	 * The brightness parameter uses the number of current steps as the unit (not the current
> +	 * value itself). Since the reported step size can vary depending on the configuration,
> +	 * this value must be converted into actual register steps.
> +	 */
> +	steps_remaining = (brightness * tps6131x->step_torch_current_ma) / TPS6131X_TORCH_STEP_I_MA;
> +
> +	num_chans = tps6131x->chan1_en + tps6131x->chan2_en + tps6131x->chan3_en;
> +
> +	/*
> +	 * The currents are distributed as evenly as possible across the activated channels.
> +	 * Since channels 1 and 3 share the same register setting, they always use the same current
> +	 * value. Channel 2 supports higher currents and thus takes over the remaining additional
> +	 * portion that cannot be covered by the other channels.
> +	 */
> +	steps_chan13 = min_t(u32, steps_remaining / num_chans,
> +			     TPS6131X_TORCH_MAX_I_CHAN13_MA / TPS6131X_TORCH_STEP_I_MA);
> +	if (tps6131x->chan1_en)
> +		steps_remaining -= steps_chan13;
> +	if (tps6131x->chan3_en)
> +		steps_remaining -= steps_chan13;
> +
> +	steps_chan2 = min_t(u32, steps_remaining,
> +			    TPS6131X_TORCH_MAX_I_CHAN2_MA / TPS6131X_TORCH_STEP_I_MA);
> +
> +	guard(mutex)(&tps6131x->lock);
> +
> +	reg0 = (steps_chan13 << TPS6131X_REG_0_DCLC13_SHIFT) |
> +	       (steps_chan2 << TPS6131X_REG_0_DCLC2_SHIFT);

Indent.

> +	ret = regmap_update_bits(tps6131x->regmap, TPS6131X_REG_0,
> +				 TPS6131X_REG_0_DCLC13 | TPS6131X_REG_0_DCLC2, reg0);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = tps6131x_set_mode(tps6131x, brightness ? TPS6131X_MODE_TORCH : TPS6131X_MODE_SHUTDOWN,
> +				true);
> +	if (ret < 0)
> +		return ret;
> +
> +	/*
> +	 * In order to use both the flash and the video light functions purely via the I2C
> +	 * interface, STRB1 must be low. If STRB1 is low, then the video light watchdog timer
> +	 * is also active, which puts the device into the shutdown state after around 13 seconds.
> +	 * To prevent this, the mode must be refreshed within the watchdog timeout.
> +	 */
> +	if (brightness)
> +		schedule_delayed_work(&tps6131x->torch_refresh_work,
> +				      TPS6131X_TORCH_REFRESH_INTERVAL_JIFFIES);
> +
> +	return 0;
> +}
> +
> +static int tps6131x_strobe_set(struct led_classdev_flash *fled_cdev, bool state)
> +{
> +	struct tps6131x *tps6131x = fled_cdev_to_tps6131x(fled_cdev);
> +	int ret;
> +
> +	guard(mutex)(&tps6131x->lock);
> +
> +	ret = tps6131x_set_mode(tps6131x, state ? TPS6131X_MODE_FLASH : TPS6131X_MODE_SHUTDOWN,
> +				true);
> +	if (ret < 0)
> +		return ret;
> +
> +	if (state) {
> +		ret = regmap_update_bits_base(tps6131x->regmap, TPS6131X_REG_3, TPS6131X_REG_3_SFT,
> +					      TPS6131X_REG_3_SFT, NULL, false, true);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	ret = regmap_update_bits_base(tps6131x->regmap, TPS6131X_REG_3, TPS6131X_REG_3_SFT, 0, NULL,
> +				      false, true);
> +	if (ret)
> +		return ret;
> +
> +	return 0;
> +}
> +
> +static int tps6131x_flash_brightness_set(struct led_classdev_flash *fled_cdev, u32 brightness)
> +{
> +	struct tps6131x *tps6131x = fled_cdev_to_tps6131x(fled_cdev);
> +	u32 num_chans;
> +	u32 steps_chan13, steps_chan2;
> +	u32 steps_remaining;
> +	int ret;
> +
> +	steps_remaining = brightness / TPS6131X_FLASH_STEP_I_MA;
> +	num_chans = tps6131x->chan1_en + tps6131x->chan2_en + tps6131x->chan3_en;
> +	steps_chan13 = min_t(u32, steps_remaining / num_chans,
> +			     TPS6131X_FLASH_MAX_I_CHAN13_MA / TPS6131X_FLASH_STEP_I_MA);
> +	if (tps6131x->chan1_en)
> +		steps_remaining -= steps_chan13;
> +	if (tps6131x->chan3_en)
> +		steps_remaining -= steps_chan13;
> +	steps_chan2 = min_t(u32, steps_remaining,
> +			    TPS6131X_FLASH_MAX_I_CHAN2_MA / TPS6131X_FLASH_STEP_I_MA);
> +
> +	guard(mutex)(&tps6131x->lock);
> +
> +	ret = regmap_update_bits(tps6131x->regmap, TPS6131X_REG_2, TPS6131X_REG_2_FC13,
> +				 steps_chan13 << TPS6131X_REG_2_FC13_SHIFT);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = regmap_update_bits(tps6131x->regmap, TPS6131X_REG_1, TPS6131X_REG_1_FC2,
> +				 steps_chan2 << TPS6131X_REG_1_FC2_SHIFT);
> +	if (ret < 0)
> +		return ret;
> +
> +	fled_cdev->brightness.val = brightness;
> +
> +	return 0;
> +}
> +
> +static int tps6131x_flash_timeout_set(struct led_classdev_flash *fled_cdev, u32 timeout_us)
> +{
> +	const struct tps6131x_timer_config *timer_config;
> +	struct tps6131x *tps6131x = fled_cdev_to_tps6131x(fled_cdev);
> +	u8 reg3;
> +	int ret;
> +
> +	guard(mutex)(&tps6131x->lock);
> +
> +	timer_config = tps6131x_find_closest_timer_config(timeout_us);
> +
> +	reg3 = timer_config->val << TPS6131X_REG_3_STIM_SHIFT;
> +	if (timer_config->range)
> +		reg3 |= TPS6131X_REG_3_SELSTIM_TO;
> +
> +	ret = regmap_update_bits(tps6131x->regmap, TPS6131X_REG_3,
> +				 TPS6131X_REG_3_STIM | TPS6131X_REG_3_SELSTIM_TO, reg3);
> +	if (ret < 0)
> +		return ret;
> +
> +	fled_cdev->timeout.val = timer_config->time_us;
> +
> +	return 0;
> +}
> +
> +static int tps6131x_strobe_get(struct led_classdev_flash *fled_cdev, bool *state)
> +{
> +	struct tps6131x *tps6131x = fled_cdev_to_tps6131x(fled_cdev);
> +	unsigned int reg3;
> +	int ret;
> +
> +	ret = regmap_read_bypassed(tps6131x->regmap, TPS6131X_REG_3, &reg3);
> +	if (ret)
> +		return ret;
> +
> +	*state = !!(reg3 & TPS6131X_REG_3_SFT);
> +
> +	return 0;
> +}
> +
> +static int tps6131x_flash_fault_get(struct led_classdev_flash *fled_cdev, u32 *fault)
> +{
> +	struct tps6131x *tps6131x = fled_cdev_to_tps6131x(fled_cdev);
> +	unsigned int reg3, reg4, reg6;
> +	int ret;
> +
> +	*fault = 0;
> +
> +	ret = regmap_read_bypassed(tps6131x->regmap, TPS6131X_REG_3, &reg3);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = regmap_read_bypassed(tps6131x->regmap, TPS6131X_REG_4, &reg4);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = regmap_read_bypassed(tps6131x->regmap, TPS6131X_REG_6, &reg6);
> +	if (ret < 0)
> +		return ret;
> +
> +	if (reg3 & TPS6131X_REG_3_HPFL)
> +		*fault |= LED_FAULT_SHORT_CIRCUIT;
> +
> +	if (reg3 & TPS6131X_REG_3_SELSTIM_TO)
> +		*fault |= LED_FAULT_TIMEOUT;
> +
> +	if (reg4 & TPS6131X_REG_4_HOTDIE_HI)
> +		*fault |= LED_FAULT_OVER_TEMPERATURE;
> +
> +	if (reg6 & (TPS6131X_REG_6_LEDHOT | TPS6131X_REG_6_LEDWARN))
> +		*fault |= LED_FAULT_LED_OVER_TEMPERATURE;
> +
> +	if (!(reg6 & TPS6131X_REG_6_LEDHDR))
> +		*fault |= LED_FAULT_UNDER_VOLTAGE;
> +
> +	if (reg6 & TPS6131X_REG_6_LEDHOT) {
> +		ret = regmap_update_bits_base(tps6131x->regmap, TPS6131X_REG_6,
> +					      TPS6131X_REG_6_LEDHOT, 0, NULL, false, true);
> +		if (ret < 0)
> +			return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static const struct led_flash_ops flash_ops = {
> +	.flash_brightness_set = tps6131x_flash_brightness_set,
> +	.strobe_set = tps6131x_strobe_set,
> +	.strobe_get = tps6131x_strobe_get,
> +	.timeout_set = tps6131x_flash_timeout_set,
> +	.fault_get = tps6131x_flash_fault_get,
> +};
> +
> +static int tps6131x_parse_node(struct tps6131x *tps6131x)
> +{
> +	const struct tps6131x_timer_config *timer_config;
> +	struct device *dev = tps6131x->dev;
> +	u32 channels[TPS6131X_MAX_CHANNELS];
> +	u32 current_step_multiplier;
> +	u32 current_ua;
> +	u32 max_current_flash_ma, max_current_torch_ma;
> +	u32 timeout_us;
> +	int num_channels;
> +	int i;
> +	int ret;
> +
> +	tps6131x->valley_current_limit = device_property_read_bool(dev, "ti,valley-current-limit");
> +
> +	tps6131x->led_node = fwnode_get_next_available_child_node(dev->fwnode, NULL);
> +	if (!tps6131x->led_node) {
> +		dev_err(dev, "Missing LED node\n");
> +		return -EINVAL;
> +	}
> +
> +	num_channels = fwnode_property_count_u32(tps6131x->led_node, "led-sources");
> +	if (num_channels <= 0) {
> +		dev_err(dev, "Failed to read led-sources property\n");
> +		return -EINVAL;
> +	}
> +
> +	if (num_channels > TPS6131X_MAX_CHANNELS) {
> +		dev_err(dev, "led-sources count %u exceeds maximum channel count %u\n",
> +			num_channels, TPS6131X_MAX_CHANNELS);
> +		return -EINVAL;
> +	}
> +
> +	ret = fwnode_property_read_u32_array(tps6131x->led_node, "led-sources", channels,
> +					     num_channels);
> +	if (ret < 0) {
> +		dev_err(dev, "Failed to read led-sources property\n");
> +		return ret;
> +	}
> +
> +	max_current_flash_ma = 0;
> +	max_current_torch_ma = 0;
> +	for (i = 0; i < num_channels; i++) {
> +		switch (channels[i]) {
> +		case 1:
> +			tps6131x->chan1_en = true;
> +			max_current_flash_ma += TPS6131X_FLASH_MAX_I_CHAN13_MA;
> +			max_current_torch_ma += TPS6131X_TORCH_MAX_I_CHAN13_MA;
> +			break;
> +		case 2:
> +			tps6131x->chan2_en = true;
> +			max_current_flash_ma += TPS6131X_FLASH_MAX_I_CHAN2_MA;
> +			max_current_torch_ma += TPS6131X_TORCH_MAX_I_CHAN2_MA;
> +			break;
> +		case 3:
> +			tps6131x->chan3_en = true;
> +			max_current_flash_ma += TPS6131X_FLASH_MAX_I_CHAN13_MA;
> +			max_current_torch_ma += TPS6131X_TORCH_MAX_I_CHAN13_MA;
> +			break;
> +		default:
> +			dev_err(dev, "led-source out of range [1-3]\n");
> +			return -EINVAL;
> +		}
> +	}
> +
> +	/*
> +	 * If only channels 1 and 3 are used, the step size is doubled because the two channels
> +	 * share the same current control register.
> +	 */
> +	current_step_multiplier =
> +		(tps6131x->chan1_en && tps6131x->chan3_en && !tps6131x->chan2_en) ? 2 : 1;
> +	tps6131x->step_flash_current_ma = current_step_multiplier * TPS6131X_FLASH_STEP_I_MA;
> +	tps6131x->step_torch_current_ma = current_step_multiplier * TPS6131X_TORCH_STEP_I_MA;
> +
> +	ret = fwnode_property_read_u32(tps6131x->led_node, "led-max-microamp", &current_ua);
> +	if (ret < 0) {
> +		dev_err(dev, "Failed to read led-max-microamp property\n");
> +		return ret;
> +	}
> +
> +	tps6131x->max_torch_current_ma = UA_TO_MA(current_ua);
> +
> +	if (!tps6131x->max_torch_current_ma ||
> +	    tps6131x->max_torch_current_ma > max_current_torch_ma ||
> +	    (tps6131x->max_torch_current_ma % tps6131x->step_torch_current_ma)) {
> +		dev_err(dev, "led-max-microamp out of range or not a multiple of %u\n",
> +			tps6131x->step_torch_current_ma);
> +		return -EINVAL;
> +	}
> +
> +	ret = fwnode_property_read_u32(tps6131x->led_node, "flash-max-microamp", &current_ua);
> +	if (ret < 0) {
> +		dev_err(dev, "Failed to read flash-max-microamp property\n");
> +		return ret;
> +	}
> +
> +	tps6131x->max_flash_current_ma = UA_TO_MA(current_ua);
> +
> +	if (!tps6131x->max_flash_current_ma ||
> +	    tps6131x->max_flash_current_ma > max_current_flash_ma ||
> +	    (tps6131x->max_flash_current_ma % tps6131x->step_flash_current_ma)) {
> +		dev_err(dev, "flash-max-microamp out of range or not a multiple of %u\n",
> +			tps6131x->step_flash_current_ma);
> +		return -EINVAL;
> +	}
> +
> +	ret = fwnode_property_read_u32(tps6131x->led_node, "flash-max-timeout-us", &timeout_us);
> +	if (ret < 0) {
> +		dev_err(dev, "Failed to read flash-max-timeout-us property\n");
> +		return ret;
> +	}
> +
> +	timer_config = tps6131x_find_closest_timer_config(timeout_us);
> +	tps6131x->max_timeout_us = timer_config->time_us;> +
> +	if (tps6131x->max_timeout_us != timeout_us)
> +		dev_warn(dev, "flash-max-timeout-us %u not supported (using %u)\n", timeout_us,
> +			 tps6131x->max_timeout_us);
> +
> +	return 0;
> +}
> +
> +static int tps6131x_led_class_setup(struct tps6131x *tps6131x)
> +{
> +	const struct tps6131x_timer_config *timer_config;
> +	struct led_classdev *led_cdev;
> +	struct led_flash_setting *setting;
> +	struct led_init_data init_data = {};
> +	int ret;
> +
> +	tps6131x->fled_cdev.ops = &flash_ops;
> +
> +	setting = &tps6131x->fled_cdev.timeout;
> +	timer_config = tps6131x_find_closest_timer_config(0);
> +	setting->min = timer_config->time_us;
> +	setting->max = tps6131x->max_timeout_us;
> +	setting->step = 1; /* Only some specific time periods are supported. No fixed step size. */
> +	setting->val = setting->min;
> +
> +	setting = &tps6131x->fled_cdev.brightness;
> +	setting->min = tps6131x->step_flash_current_ma;
> +	setting->max = tps6131x->max_flash_current_ma;
> +	setting->step = tps6131x->step_flash_current_ma;
> +	setting->val = setting->min;
> +
> +	led_cdev = &tps6131x->fled_cdev.led_cdev;
> +	led_cdev->brightness_set_blocking = tps6131x_brightness_set;
> +	led_cdev->max_brightness = tps6131x->max_torch_current_ma;
> +	led_cdev->flags |= LED_DEV_CAP_FLASH;
> +
> +	init_data.fwnode = tps6131x->led_node;
> +	init_data.devicename = NULL;
> +	init_data.default_label = NULL;
> +	init_data.devname_mandatory = false;
> +
> +	ret = devm_led_classdev_flash_register_ext(tps6131x->dev, &tps6131x->fled_cdev,
> +						   &init_data);
> +	if (ret)
> +		return ret;
> +
> +	return 0;
> +}
> +
> +static int tps6131x_flash_external_strobe_set(struct v4l2_flash *v4l2_flash, bool enable)
> +{
> +	struct led_classdev_flash *fled_cdev = v4l2_flash->fled_cdev;
> +	struct tps6131x *tps6131x = fled_cdev_to_tps6131x(fled_cdev);
> +
> +	guard(mutex)(&tps6131x->lock);
> +
> +	return tps6131x_set_mode(tps6131x, enable ? TPS6131X_MODE_FLASH : TPS6131X_MODE_SHUTDOWN,
> +				 false);
> +}
> +
> +static const struct v4l2_flash_ops tps6131x_v4l2_flash_ops = {
> +	.external_strobe_set = tps6131x_flash_external_strobe_set,
> +};
> +
> +static int tps6131x_v4l2_setup(struct tps6131x *tps6131x)
> +{
> +	struct v4l2_flash_config v4l2_cfg = { 0 };
> +	struct led_flash_setting *intensity = &v4l2_cfg.intensity;
> +
> +	intensity->min = tps6131x->step_torch_current_ma;
> +	intensity->max = tps6131x->max_torch_current_ma;
> +	intensity->step = tps6131x->step_torch_current_ma;
> +	intensity->val = intensity->min;
> +
> +	strscpy(v4l2_cfg.dev_name, tps6131x->fled_cdev.led_cdev.dev->kobj.name,
> +		sizeof(v4l2_cfg.dev_name));
> +
> +	v4l2_cfg.has_external_strobe = true;
> +	v4l2_cfg.flash_faults = LED_FAULT_TIMEOUT | LED_FAULT_OVER_TEMPERATURE |
> +				LED_FAULT_SHORT_CIRCUIT | LED_FAULT_UNDER_VOLTAGE |
> +				LED_FAULT_LED_OVER_TEMPERATURE;
> +
> +	tps6131x->v4l2_flash = v4l2_flash_init(tps6131x->dev, tps6131x->led_node,
> +					       &tps6131x->fled_cdev, &tps6131x_v4l2_flash_ops,
> +					       &v4l2_cfg);
> +	if (IS_ERR(tps6131x->v4l2_flash)) {
> +		dev_err(tps6131x->dev, "Failed to initialize v4l2 flash LED\n");
> +		return PTR_ERR(tps6131x->v4l2_flash);
> +	}
> +
> +	return 0;
> +}
> +
> +static int tps6131x_probe(struct i2c_client *client)
> +{
> +	struct tps6131x *tps6131x;
> +	int ret;
> +
> +	tps6131x = devm_kzalloc(&client->dev, sizeof(*tps6131x), GFP_KERNEL);
> +	if (!tps6131x)
> +		return -ENOMEM;
> +
> +	tps6131x->dev = &client->dev;
> +	i2c_set_clientdata(client, tps6131x);

If you already have client, to fetch this, you'll already have access to dev.

> +	mutex_init(&tps6131x->lock);
> +	INIT_DELAYED_WORK(&tps6131x->torch_refresh_work, tps6131x_torch_refresh_handler);
> +
> +	ret = tps6131x_parse_node(tps6131x);
> +	if (ret)
> +		return -ENODEV;

Why aren't we propagating the real error?

> +	tps6131x->regmap = devm_regmap_init_i2c(client, &tps6131x_regmap);
> +	if (IS_ERR(tps6131x->regmap)) {
> +		ret = PTR_ERR(tps6131x->regmap);

Use dev_err_ptr_probe() instead.

> +		return dev_err_probe(&client->dev, ret, "Failed to allocate register map\n");
> +	}
> +
> +	tps6131x->reset_gpio = devm_gpiod_get_optional(&client->dev, "reset", GPIOD_OUT_HIGH);
> +	if (IS_ERR(tps6131x->reset_gpio)) {
> +		ret = PTR_ERR(tps6131x->reset_gpio);
> +		return dev_err_probe(&client->dev, ret, "Failed to get reset GPIO\n");
> +	}
> +
> +	ret = tps6131x_reset_chip(tps6131x);
> +	if (ret)
> +		return dev_err_probe(&client->dev, ret, "Failed to reset LED controller\n");
> +
> +	ret = tps6131x_init_chip(tps6131x);
> +	if (ret)
> +		return dev_err_probe(&client->dev, ret, "Failed to initialize LED controller\n");
> +
> +	ret = tps6131x_led_class_setup(tps6131x);
> +	if (ret)
> +		return dev_err_probe(&client->dev, ret, "Failed to setup LED class\n");
> +
> +	ret = tps6131x_v4l2_setup(tps6131x);
> +	if (ret)
> +		return dev_err_probe(&client->dev, ret, "Failed to setup v4l2 flash\n");
> +
> +	return 0;
> +}
> +
> +static void tps6131x_remove(struct i2c_client *client)
> +{
> +	struct tps6131x *tps6131x = i2c_get_clientdata(client);
> +
> +	v4l2_flash_release(tps6131x->v4l2_flash);
> +
> +	cancel_delayed_work_sync(&tps6131x->torch_refresh_work);
> +}
> +
> +static const struct of_device_id of_tps6131x_leds_match[] = {
> +	{ .compatible = "ti,tps61310" },
> +	{}
> +};
> +MODULE_DEVICE_TABLE(of, of_tps6131x_leds_match);
> +
> +static struct i2c_driver tps6131x_i2c_driver = {
> +	.driver = {
> +		.name = "tps6131x",
> +		.of_match_table = of_tps6131x_leds_match,
> +	},
> +	.probe = tps6131x_probe,
> +	.remove = tps6131x_remove,
> +};
> +module_i2c_driver(tps6131x_i2c_driver);
> +
> +MODULE_DESCRIPTION("Texas Instruments TPS6131X flash LED driver");
> +MODULE_AUTHOR("Matthias Fend <matthias.fend@...end.at>");
> +MODULE_LICENSE("GPL");
> 
> -- 
> 2.34.1
> 

-- 
Lee Jones [李琼斯]

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