cleanup LED documentation and make it match reality

sysfs-class-led fails to mention some important details. Also fix led
vs LED and english.
Signed-off-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Jacek Anaszewski <j.anaszewski@samsung.com>

Documentation/ABI/testing/sysfs-class-led

@@ -4,16 +4,24 @@ 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
+		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.
 
+		Writing 0 to this file clears active trigger.
+
+		Writing non-zero to this file while trigger is active changes the
+		top brightness trigger is going to use.
+
 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).
+		Maximum brightness level for this LED, default is 255 (LED_FULL).
+
+		If the LED does not support different brightness levels, this
+		should be 1.
 
 What:		/sys/class/leds/<led>/trigger
 Date:		March 2006
@@ -21,7 +29,7 @@ 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.
+		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. For