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

Lee Jones
2024-06-13T07:57:21Z

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>
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