Re: [PATCH 1/1] leds: core: Omit set_brightness error message for a LED supporting hw trigger only

Lee Jones
2024-06-20T09:09:36Z

On Thu, 13 Jun 2024, Lee Jones wrote:

> If both set_brightness functions return -ENOTSUPP, then the LED doesn't
> support setting a fixed brightness value, and the error message isn't
> helpful. This can be the case e.g. for LEDs supporting a specific hw
> trigger only.
>
> Pinched the subject line and commit message from Heiner:
> Link: https://lore.kernel.org/all/44177e37-9512-4044-8991-bb23b184bf37@gmail.com/
>
> Reworked the function to provide Heiner's required semantics whilst
> simultaneously increasing readability and flow.
>
> Cc: Pavel Machek <pavel@ucw.cz>
> Cc: linux-leds@vger.kernel.org
> Suggested-by: Heiner Kallweit <hkallweit1@gmail.com>

Heiner, you good with this solution?

A Tested-by or Reviewed-by would be good if you have the time.

> Signed-off-by: Lee Jones <lee@kernel.org>
> ---
> drivers/leds/led-core.c | 19 +++++++++++++------
> 1 file changed, 13 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/leds/led-core.c b/drivers/leds/led-core.c
> index ef7d1c6767ca..3b4db39f2326 100644
> --- a/drivers/leds/led-core.c
> +++ b/drivers/leds/led-core.c
> @@ -123,15 +123,22 @@ static void led_timer_function(struct timer_list *t)
> static void set_brightness_delayed_set_brightness(struct led_classdev *led_cdev,
> unsigned int value)
> {
> - int ret = 0;
> + int ret;
>
> ret = __led_set_brightness(led_cdev, value);
> - if (ret == -ENOTSUPP)
> + if (ret == -ENOTSUPP) {
> ret = __led_set_brightness_blocking(led_cdev, value);
> - if (ret < 0 &&
> - /* LED HW might have been unplugged, therefore don't warn */
> - !(ret == -ENODEV && (led_cdev->flags & LED_UNREGISTERING) &&
> - (led_cdev->flags & LED_HW_PLUGGABLE)))
> + if (ret == -ENOTSUPP)
> + /* No back-end support to set a fixed brightness value */
> + return;
> + }
> +
> + /* LED HW might have been unplugged, therefore don't warn */
> + if (ret == -ENODEV && led_cdev->flags & LED_UNREGISTERING &&
> + led_cdev->flags & LED_HW_PLUGGABLE)
> + return;
> +
> + if (ret < 0)
> dev_err(led_cdev->dev,
> "Setting an LED's brightness failed (%d)\n", ret);
> }
> --
> 2.45.2.505.gda0bf45e8d-goog
>

--
Lee Jones [李琼斯]