Re: [PATCH v9 13/15] leds: lp55xx: Update the lp55xx to use the multi color framework

[Jacek Anaszewski]

Dan,

On 9/26/19 2:02 PM, Dan Murphy wrote:
> Jacek
> 
> On 9/25/19 5:00 PM, Jacek Anaszewski wrote:
>> Dan,
>>
>> On 9/25/19 7:46 PM, Dan Murphy wrote:
>>> Update the lp5523 to allow the use of the multi color framework.
>>>
>>> Signed-off-by: Dan Murphy <dmurphy@xxxxxx>
>>> ---
>>> Â drivers/leds/KconfigÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |ÂÂ 1 +
>>> Â drivers/leds/leds-lp5523.cÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ |Â 13 ++
>>> Â drivers/leds/leds-lp55xx-common.cÂÂÂÂÂÂÂÂ | 150 ++++++++++++++++++----
>>> Â drivers/leds/leds-lp55xx-common.hÂÂÂÂÂÂÂÂ |Â 11 ++
>>> Â include/linux/platform_data/leds-lp55xx.h |ÂÂ 6 +
>>> Â 5 files changed, 157 insertions(+), 24 deletions(-)
>>>
>>> diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
>>> index 84f60e35c5ee..dc3d9f2194cd 100644
>>> --- a/drivers/leds/Kconfig
>>> +++ b/drivers/leds/Kconfig
>>> @@ -377,6 +377,7 @@ config LEDS_LP50XX
>>> Â config LEDS_LP55XX_COMMON
>>> ÂÂÂÂÂ tristate "Common Driver for TI/National
>>> LP5521/5523/55231/5562/8501"
>>> ÂÂÂÂÂ depends on LEDS_LP5521 || LEDS_LP5523 || LEDS_LP5562 ||
>>> LEDS_LP8501
>>> +ÂÂÂ depends on LEDS_CLASS_MULTI_COLOR && OF
>>> ÂÂÂÂÂ select FW_LOADER
>>> ÂÂÂÂÂ select FW_LOADER_USER_HELPER
>>> ÂÂÂÂÂ help
>>> diff --git a/drivers/leds/leds-lp5523.c b/drivers/leds/leds-lp5523.c
>>> index d0b931a136b9..8b2cdb98fed6 100644
>>> --- a/drivers/leds/leds-lp5523.c
>>> +++ b/drivers/leds/leds-lp5523.c
>>> @@ -791,6 +791,18 @@ static ssize_t store_master_fader_leds(struct
>>> device *dev,
>>> ÂÂÂÂÂ return ret;
>>> Â }
>>> Â +static int lp5523_led_intensity(struct lp55xx_led *led, int chan_num)
>> Why do we need this function? brightness op will not suffice?
> 
> I looked at this before sending it in. This API adds the chan_num to
> write to.
> 
> The brightness_fn does not it takes it from the led structure.
> 
>>
>>> +{
>>> +ÂÂÂ struct lp55xx_chip *chip = led->chip;
>>> +ÂÂÂ int ret;
>>> +
>>> +ÂÂÂ mutex_lock(&chip->lock);
>>> +ÂÂÂ ret = lp55xx_write(chip, LP5523_REG_LED_PWM_BASE + chan_num,
>>> +ÂÂÂÂÂÂÂÂÂÂÂÂ led->brightness);
>>> +ÂÂÂ mutex_unlock(&chip->lock);
>>> +ÂÂÂ return ret;
>>> +}
>>> +
>>> Â static int lp5523_led_brightness(struct lp55xx_led *led)
>>> Â {
>>> ÂÂÂÂÂ struct lp55xx_chip *chip = led->chip;
>>> @@ -857,6 +869,7 @@ static struct lp55xx_device_config lp5523_cfg = {
>>>  .max_channel = LP5523_MAX_LEDS,
>>> ÂÂÂÂÂ .post_init_deviceÂÂ = lp5523_post_init_device,
>>> ÂÂÂÂÂ .brightness_fnÂÂÂÂÂ = lp5523_led_brightness,
>>> +ÂÂÂ .color_intensity_fn = lp5523_led_intensity,
>>> ÂÂÂÂÂ .set_led_currentÂÂÂ = lp5523_set_led_current,
>>> ÂÂÂÂÂ .firmware_cbÂÂÂÂÂÂÂ = lp5523_firmware_loaded,
>>> ÂÂÂÂÂ .run_engineÂÂÂÂÂÂÂÂ = lp5523_run_engine,
>>> diff --git a/drivers/leds/leds-lp55xx-common.c
>>> b/drivers/leds/leds-lp55xx-common.c
>>> index 44ced02b49f9..0e4b3a9d3047 100644
>>> --- a/drivers/leds/leds-lp55xx-common.c
>>> +++ b/drivers/leds/leds-lp55xx-common.c
>>> @@ -136,9 +136,26 @@ static int lp55xx_set_brightness(struct
>>> led_classdev *cdev,
>>> Â {
>>> ÂÂÂÂÂ struct lp55xx_led *led = cdev_to_lp55xx_led(cdev);
>>> ÂÂÂÂÂ struct lp55xx_device_config *cfg = led->chip->cfg;
>>> +ÂÂÂ int brightness_val[LP55XX_MAX_GROUPED_CHAN];
>>> +ÂÂÂ int ret;
>>> +ÂÂÂ int i;
>>> +
>>> +ÂÂÂ if (led->mc_cdev.num_leds > 1) {
>>> +ÂÂÂÂÂÂÂ led_mc_calc_brightness(&led->mc_cdev,
>>> +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ brightness, brightness_val);
>>> +ÂÂÂÂÂÂÂ for (i = 0; i < led->mc_cdev.num_leds; i++) {
>>> +ÂÂÂÂÂÂÂÂÂÂÂ led->brightness = brightness_val[i];
>>> +ÂÂÂÂÂÂÂÂÂÂÂ ret = cfg->color_intensity_fn(led,
>>> +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ led->grouped_channels[i]);
>> Now we will have three separate calls for each color component
>> (and possibly sleeping on mutex on contention).
>>
>> Probably LED mc class use case will need a bit different design.
>>
>> Also, instead of grouped_channels we could possibly have
>>
>> led_mc_get_color_id(&led->mc_dev, i)
> color_id and grouped_channels are not a 1:1 mapping

OK, they're channel numbers.

>> which would map entry position index to color_id.
>>
>> I will stop reviewing here and will continue after taking
>> deeper look at this lp55xx design.

I've analyzed that design in greater detail and have started
to wonder why you can't pass two arrays to the new op:
channel numbers and corresponding calculated channel intensities?

-- 
Best regards,
Jacek Anaszewski