Re: [PATCH v3 2/2] leds: tps6131x: add support for Texas Instruments TPS6131X flash LED driver

Matthias Fend
2025-05-02T10:18:56Z

Hi Lee,

thank you for taking the time for this review.

Am 01.05.2025 um 13:03 schrieb Lee Jones:
> 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@emfend.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@emfend.at>
>> +L: linux-leds@vger.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@kernel.org>
>> L: linux-iio@vger.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@emfend.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.

Okay, I'll remove them.

>
>> +#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)

I actually like that too, but I couldn't convince clang-format to keep
the spaces. The automatic formatting was more valuable to me in the end.
If you know how to have both, I'd be very happy :)

>
>> +#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?

At the point where the timer starts, there's a comment that says the
register must be updated within a timeout of 13 seconds.
So I thought 10 seconds would be a nice, appropriate interval.

>
>> +#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?

The values ​​are fixed because they are written directly to a register.
In V1, I used an enum without values ​​and mapped it to the register
value in a function. I was asked to omit this mapping and use the enum
directly.

TLDR:
[x] stone
[ ] 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?

Initially, I only had the bare values ​​here, so that no one would
mistakenly think that something could be changed here.
This information only contains the information about the reset state of
the registers from the datasheet.
The contents are only needed for correct cache handling and have no
meaning for the driver itself.
If I now create a separate 'INITIAL' define for each value, which is
only used here, it would probably make it a bit harder to read, wouldn't
it? What do you think?

>
>> + { 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?

Of course, I could simply omit that. But the point was that I had to
describe which fields have which values.
If I omitted that, the information would somehow disappear.

>
>> + { 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.

ACK.

>
>> + */
>> +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?

Since the register space for this chip is very small, simple, compact,
and contiguous, I think this is the right cache type for it. Did I miss
something here?

>> + .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'?

This way, it's easy to spot a mistake. Each line can only contain parts
that use the same 'reg<x>'.
But I can easily change it and use only one variable.

>
>> + 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.

I'm happy to adapt the code here as well, but unfortunately I haven't
quite figured out how you'd like it to look. Could you please tell me
more specifically what I should change?

>
>> + 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.

ACK.

>
>> +
>> + 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.

That's true. I wasn't sure how to respond to this, other than just keep
trying.
What do you think about not starting the timer in case of an error and
instead outputting a message with dev_err?

>
>> +
>> + 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?

I will do so.

>
>> + 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.

The indent was intention ;) The operands of arithmetic assignments are
at least intentionally and automatically aligned to be on the same
column. This is also the case elsewhere in the code.
What is the alternative expectation here?

>
>> + 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.

I understand that in principle. However, I'm still not entirely sure
what exactly I should change. Could you please provide me with some
further guidance?

>
>> + 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?

Good point. I'll change that.

>
>> + 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.

Hmm, I don't quite understand that. dev_err_ptr_probe() returns an error
pointer instead of an int, right?

Thanks again for your review.
~Matthias

>
>> + 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@emfend.at>");
>> +MODULE_LICENSE("GPL");
>>
>> --
>> 2.34.1
>>
>