kernel/linux.git/drivers/leds/led-core.c, branch v6.12.80

leds: Fix LED_OFF brightness race

2025-04-10T12:39:21+00:00

[ Upstream commit 2c70953b6f535f7698ccbf22c1f5ba26cb6c2816 ] While commit fa15d8c69238 ("leds: Fix set_brightness_delayed() race") successfully forces led_set_brightness() to be called with LED_OFF at least once when switching from blinking to LED on state so that hw-blinking can be disabled, another race remains. Indeed in led_set_brightness(LED_OFF) followed by led_set_brightness(any) scenario the following CPU scheduling can happen: CPU0 CPU1 ---- ---- set_brightness_delayed() { test_and_clear_bit(BRIGHTNESS_OFF) led_set_brightness(LED_OFF) { set_bit(BRIGHTNESS_OFF) queue_work() } led_set_brightness(any) { set_bit(BRIGHTNESS) queue_work() //already queued } test_and_clear_bit(BRIGHTNESS) /* LED set with brightness any */ } /* From previous CPU1 queue_work() */ set_brightness_delayed() { test_and_clear_bit(BRIGHTNESS_OFF) /* LED turned off */ test_and_clear_bit(BRIGHTNESS) /* Clear from previous run, LED remains off */ In that case the led_set_brightness(LED_OFF)/led_set_brightness(any) sequence will be effectively executed in reverse order and LED will remain off. With the introduction of commit 32360bf6a5d4 ("leds: Introduce ordered workqueue for LEDs events instead of system_wq") the race is easier to trigger as sysfs brightness configuration does not wait for set_brightness_delayed() work to finish (flush_work() removal). Use delayed_set_value to optionnally re-configure brightness after a LED_OFF. That way a LED state could be configured more that once but final state will always be as expected. Ensure that delayed_set_value modification is seen before set_bit() using smp_mb__before_atomic(). Fixes: fa15d8c69238 ("leds: Fix set_brightness_delayed() race") Signed-off-by: Remi Pommarel Reviewed-by: Hans de Goede Link: https://lore.kernel.org/r/19c81177059dab7b656c42063958011a8e4d1a66.1740050412.git.repk@triplefau.lt Signed-off-by: Lee Jones Signed-off-by: Sasha Levin

leds: core: Omit set_brightness error message for a LED supporting hw trigger only

2024-06-26T15:55:44+00:00

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 Cc: linux-leds@vger.kernel.org Suggested-by: Heiner Kallweit Reviewed-by: Heiner Kallweit Signed-off-by: Lee Jones

Merge branches 'ib-leds-mfd-6.11', 'ib-leds-platform-power-6.11' and 'ib-mfd-leds-platform-6.11' into ibs-for-leds-merged

2024-06-21T10:54:35+00:00

leds: core: Unexport led_colors[] array

2024-06-21T10:41:39+00:00

There are no external users left, make the array static. Signed-off-by: Thomas Weißschuh Link: https://lore.kernel.org/r/20240613-cros_ec-led-v3-3-500b50f41e0f@weissschuh.net Signed-off-by: Lee Jones

leds: core: Introduce led_get_color_name() function

2024-06-21T10:41:32+00:00

This is similar to the existing led_colors[] array but is safer to use and usable by everyone. Getting string representations of color ids is useful for drivers which are handling color IDs anyways, for example for the multicolor API. Signed-off-by: Thomas Weißschuh Link: https://lore.kernel.org/r/20240613-cros_ec-led-v3-1-500b50f41e0f@weissschuh.net Signed-off-by: Lee Jones

leds: core: Add led_mc_set_brightness() function

2024-05-31T11:57:41+00:00

Add a new led_mc_set_brightness() function for in kernel color/brightness changing of multi-color LEDs. led-class-multicolor can be build as a module and led_mc_set_brightness() will have the builtin callers, so put led_mc_set_brightness() inside led-core instead, just like how led_set_brightness() is part of the core and not of the led-class object. This also adds a new LED_MULTI_COLOR led_classdev flag to allow led_mc_set_brightness() to verify that it is operating on a multi-color LED classdev, avoiding casting the passed in LED classdev to a multi-color LED classdev, when it actually is not a multi-color LED. Signed-off-by: Hans de Goede Reviewed-by: Jacek Anaszewski Reviewed-by: Andy Shevchenko Link: https://lore.kernel.org/r/20240531114124.45346-5-hdegoede@redhat.com Signed-off-by: Lee Jones

Merge tag 'leds-next-6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/leds

2023-11-03T00:53:19+00:00

Pull LED updates from Lee Jones: "Core Frameworks: - Add support for a bunch more colours New Drivers: - Add support for Kinetic KTD2026/7 RGB/White LEDs New Functionality: - Add support for device to enter HW Controlled Mode to Turris Omnia LEDs - Add support for HW Gamma Correction to Turris Omnia LEDs Fix-ups: - Apply new __counted_by() annotation to several data structures containing flexible arrays - Rid the return value from Platform's .remove() operation - Use *_cansleep() variants for instances were threads can sleep - Improve the semantics when setting the brightness - Generic clean-ups; code reduction, coding style, standard patterns - Replace strncpy() with strscpy() - Fix-up / add various documentation - Re-author the GPIO associated Trigger to use trigger-sources - Move to using standard APIs and helpers - Improve error checking - Stop using static GPIO bases Bug Fixes: - Fix Pointer to Enum casing warnings - Do not pretend that I2C backed device supports SMBUS - Ensure PWM LEDs are extinguished when disabled, rather than held in a state - Fix 'output may be truncated' warnings" * tag 'leds-next-6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/leds: (43 commits) leds: lp5521: Add an error check in lp5521_post_init_device leds: gpio: Update headers leds: gpio: Remove unneeded assignment leds: gpio: Move temporary variable for struct device to gpio_led_probe() leds: gpio: Refactor code to use devm_gpiod_get_index_optional() leds: gpio: Utilise PTR_ERR_OR_ZERO() leds: gpio: Keep driver firmware interface agnostic leds: core: Refactor led_update_brightness() to use standard pattern leds: turris-omnia: Fix brightness setting and trigger activating leds: sc27xx: Move mutex_init() down leds: trigger: netdev: Move size check in set_device_name leds: Add ktd202x driver dt-bindings: leds: Add Kinetic KTD2026/2027 LED leds: core: Add more colors from DT bindings to led_colors dt-bindings: leds: Last color ID is now 14 (LED_COLOR_ID_LIME) leds: tca6507: Don't use fixed GPIO base leds: lp3952: Convert to use maple tree register cache leds: lm392x: Convert to use maple tree register cache leds: aw200xx: Convert to use maple tree register cache leds: lm3601x: Convert to use maple tree register cache ...

leds: core: Refactor led_update_brightness() to use standard pattern

2023-11-01T11:29:18+00:00

The standard conditional pattern is to check for errors first and bail out if any. Refactor led_update_brightness() accordingly. While at it, drop unneeded assignment and return 0 unconditionally on success. Signed-off-by: Andy Shevchenko Acked-by: Denis Osterland-Heim Reviewed-by: Hans de Goede Link: https://lore.kernel.org/r/20231016153051.1409074-1-andriy.shevchenko@linux.intel.com Signed-off-by: Lee Jones

leds: core: Add more colors from DT bindings to led_colors

2023-11-01T11:29:06+00:00

The colors are already part of DT bindings. Make sure the kernel is able to convert them to strings. Signed-off-by: Ondrej Jirman Link: https://lore.kernel.org/r/20231008144014.1180334-1-megi@xff.cz Signed-off-by: Lee Jones

leds: Drop BUG_ON check for LED_COLOR_ID_MULTI

2023-09-19T14:16:23+00:00

Commit c3f853184bed ("leds: Fix BUG_ON check for LED_COLOR_ID_MULTI that is always false") fixed a no-op BUG_ON. This turned out to cause a regression, since some in-tree device-tree files already use LED_COLOR_ID_MULTI. Drop the BUG_ON altogether. Fixes: c3f853184bed ("leds: Fix BUG_ON check for LED_COLOR_ID_MULTI that is always false") Reported-by: Da Xue Closes: https://lore.kernel.org/linux-leds/ZQLelWcNjjp2xndY@duo.ucw.cz/T/ Signed-off-by: Marek Behún Link: https://lore.kernel.org/r/20230918140724.18634-1-kabel@kernel.org Signed-off-by: Lee Jones