led: document sysfs interface
Also fix Documentation/led-class.txt, the acceptable
range of values for brightness is 0-max_brightness, not 0-255.
Cc: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Corentin Chary <corentincj@iksaif.net>
Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/Documentation/ABI/testing/sysfs-class-led b/Documentation/ABI/testing/sysfs-class-led
new file mode 100644
index 0000000..9e4541d
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-class-led
@@ -0,0 +1,28 @@
+What: /sys/class/leds/<led>/brightness
+Date: March 2006
+KernelVersion: 2.6.17
+Contact: Richard Purdie <rpurdie@rpsys.net>
+Description:
+ Set the brightness of the LED. Most LEDs don't
+ have hardware brightness support so will just be turned on for
+ non-zero brightness settings. The value is between 0 and
+ /sys/class/leds/<led>/max_brightness.
+
+What: /sys/class/leds/<led>/max_brightness
+Date: March 2006
+KernelVersion: 2.6.17
+Contact: Richard Purdie <rpurdie@rpsys.net>
+Description:
+ Maximum brightness level for this led, default is 255 (LED_FULL).
+
+What: /sys/class/leds/<led>/trigger
+Date: March 2006
+KernelVersion: 2.6.17
+Contact: Richard Purdie <rpurdie@rpsys.net>
+Description:
+ Set the trigger for this LED. A trigger is a kernel based source
+ of led events.
+ You can change triggers in a similar manner to the way an IO
+ scheduler is chosen. Trigger specific parameters can appear in
+ /sys/class/leds/<led> once a given trigger is selected.
+