Patch "leds: trigger: Store brightness set by led_trigger_event()" has been added to the 5.15-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    leds: trigger: Store brightness set by led_trigger_event()

to the 5.15-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     leds-trigger-store-brightness-set-by-led_trigger_eve.patch
and it can be found in the queue-5.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 25f994fb471bf3fa777063d0db72beb7a9c36513
Author: Heiner Kallweit <hkallweit1@xxxxxxxxx>
Date:   Mon Mar 4 21:57:30 2024 +0100

    leds: trigger: Store brightness set by led_trigger_event()
    
    [ Upstream commit 822c91e72eac568ed8d83765634f00decb45666c ]
    
    If a simple trigger is assigned to a LED, then the LED may be off until
    the next led_trigger_event() call. This may be an issue for simple
    triggers with rare led_trigger_event() calls, e.g. power supply
    charging indicators (drivers/power/supply/power_supply_leds.c).
    Therefore persist the brightness value of the last led_trigger_event()
    call and use this value if the trigger is assigned to a LED.
    In addition add a getter for the trigger brightness value.
    
    Signed-off-by: Heiner Kallweit <hkallweit1@xxxxxxxxx>
    Reviewed-by: Takashi Iwai <tiwai@xxxxxxx>
    Link: https://lore.kernel.org/r/b1358b25-3f30-458d-8240-5705ae007a8a@xxxxxxxxx
    Signed-off-by: Lee Jones <lee@xxxxxxxxxx>
    Stable-dep-of: ab477b766edd ("leds: triggers: Flush pending brightness before activating trigger")
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/leds/led-triggers.c b/drivers/leds/led-triggers.c
index dddfc301d3414..cdb446cb84af2 100644
--- a/drivers/leds/led-triggers.c
+++ b/drivers/leds/led-triggers.c
@@ -193,11 +193,11 @@ int led_trigger_set(struct led_classdev *led_cdev, struct led_trigger *trig)
 		spin_unlock(&trig->leddev_list_lock);
 		led_cdev->trigger = trig;
 
+		ret = 0;
 		if (trig->activate)
 			ret = trig->activate(led_cdev);
 		else
-			ret = 0;
-
+			led_set_brightness(led_cdev, trig->brightness);
 		if (ret)
 			goto err_activate;
 
@@ -372,6 +372,8 @@ void led_trigger_event(struct led_trigger *trig,
 	if (!trig)
 		return;
 
+	trig->brightness = brightness;
+
 	rcu_read_lock();
 	list_for_each_entry_rcu(led_cdev, &trig->led_cdevs, trig_list)
 		led_set_brightness(led_cdev, brightness);
diff --git a/include/linux/leds.h b/include/linux/leds.h
index 2bbff7519b731..79ab2dfd3c72f 100644
--- a/include/linux/leds.h
+++ b/include/linux/leds.h
@@ -356,6 +356,9 @@ struct led_trigger {
 	int		(*activate)(struct led_classdev *led_cdev);
 	void		(*deactivate)(struct led_classdev *led_cdev);
 
+	/* Brightness set by led_trigger_event */
+	enum led_brightness brightness;
+
 	/* LED-private triggers have this set */
 	struct led_hw_trigger_type *trigger_type;
 
@@ -409,6 +412,12 @@ static inline void *led_get_trigger_data(struct led_classdev *led_cdev)
 	return led_cdev->trigger_data;
 }
 
+static inline enum led_brightness
+led_trigger_get_brightness(const struct led_trigger *trigger)
+{
+	return trigger ? trigger->brightness : LED_OFF;
+}
+
 #define module_led_trigger(__led_trigger) \
 	module_driver(__led_trigger, led_trigger_register, \
 		      led_trigger_unregister)
@@ -445,6 +454,12 @@ static inline void *led_get_trigger_data(struct led_classdev *led_cdev)
 	return NULL;
 }
 
+static inline enum led_brightness
+led_trigger_get_brightness(const struct led_trigger *trigger)
+{
+	return LED_OFF;
+}
+
 #endif /* CONFIG_LEDS_TRIGGERS */
 
 /* Trigger specific functions */