Commit 822c91e7 authored by Heiner Kallweit's avatar Heiner Kallweit Committed by Lee Jones
Browse files

leds: trigger: Store brightness set by led_trigger_event() 



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: default avatarHeiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: default avatarTakashi Iwai <tiwai@suse.de>
Link: https://lore.kernel.org/r/b1358b25-3f30-458d-8240-5705ae007a8a@gmail.com


Signed-off-by: default avatarLee Jones <lee@kernel.org>
parent 4cece764

drivers/leds/led-triggers.c

+4 −2
Original line number Diff line number Diff line
@@ -194,11 +194,11 @@ 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;
@@ -387,6 +387,8 @@ 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);

include/linux/leds.h

+15 −0
Original line number Diff line number Diff line
@@ -455,6 +455,9 @@ 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;
@@ -508,6 +511,12 @@ 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)
@@ -544,6 +553,12 @@ 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 enum */