Documentation: leds: Add description of brightness setting API

This patch adds description of the LED subsystem API for
setting an LED brightness.

Signed-off-by: Jacek Anaszewski <j.anaszewski@samsung.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>

diff --git a/Documentation/leds/leds-class.txt b/Documentation/leds/leds-class.txt
index 62261c04060a73bef82a3a6784cef794d39e5d50..d406d98339b25abbe3d1f5f05c4ac7f9856d3e9c 100644 (file)
--- a/Documentation/leds/leds-class.txt
+++ b/Documentation/leds/leds-class.txt
@@ -52,6 +52,19 @@ 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 API
+======================
+
+LED subsystem core exposes following API for setting brightness:
+
+    - led_set_brightness : it is guaranteed not to sleep, passing LED_OFF stops
+               blinking,
+    - led_set_brightness_sync : for use cases when immediate effect is desired -
+               it can block the caller for the time required for accessing
+               device registers and can sleep, passing LED_OFF stops hardware
+               blinking, returns -EBUSY if software blink fallback is enabled.
+
+
 Hardware accelerated blink of LEDs
 ==================================