[PATCH/RFC v5 11/57] Documentation: leds: Add description of brightness_set* ops
From: Jacek Anaszewski
Date: Tue Aug 11 2015 - 05:39:04 EST
This patch adds description of brightness_set and a recently introduced
Signed-off-by: Jacek Anaszewski <j.anaszewski@xxxxxxxxxxx>
Cc: Bryan Wu <cooloney@xxxxxxxxx>
Cc: Andrew Lunn <andrew@xxxxxxx>
Cc: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
Cc: Pavel Machek <pavel@xxxxxx>
Cc: Stas Sergeev <stsp@xxxxxxxxxxxxxxxxxxxxx>
Documentation/leds/leds-class.txt | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
diff --git a/Documentation/leds/leds-class.txt b/Documentation/leds/leds-class.txt
index 62261c0..fde8fef 100644
@@ -52,6 +52,26 @@ above leaves scope for further attributes should they be needed. If sections
of the name don't apply, just leave that section blank.
+Brightness setting callbacks
+LED subsystem core exposes two function pointers for setting brightness:
+ - brightness_set : Intended for drivers that may set brightness in
+ a blocking way. For a long time this was the only
+ op for setting brightness and it was drivers'
+ responsibility to assure that it will not block the
+ caller. With the new approach drivers are required to set
+ LED_BRIGHTNESS_BLOCKING flag, when using this op, to make
+ LED core aware that it should call it from a work queue
+ task, when brightness is set with led_set_brightness API.
+ In case synchronous operation is needed it should be
+ explicitly requested with led_set_brightness_sync API.
+ - brightness_set_nonblocking : Intended for drivers that set brightness in
+ a non-blocking way.
Hardware accelerated blink of LEDs
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