path: root/Documentation
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authorLinus Torvalds <torvalds@linux-foundation.org>2008-04-25 12:48:44 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-04-25 12:48:44 -0700
commiteb855fd8e7f6b1d8b50f24aa36803e29b367b041 (patch)
tree0d6606a4285f3312c9fd9d7507203c9b095e5443 /Documentation
parentbf16ae250999e76aff0491a362073a552db965fc (diff)
parent060856c799191ffc360105cac49f3f9e68d526b7 (diff)
Merge branch 'for-linus' of git://git.o-hand.com/linux-rpurdie-leds
* 'for-linus' of git://git.o-hand.com/linux-rpurdie-leds: leds: Add default-on trigger leds: Document the context brightness_set needs leds: Add new driver for the LEDs on the Freecom FSG-3 leds: Add support to leds with readable status leds: enable support for blink_set() platform hook in leds-gpio leds: Cleanup various whitespace and code style issues leds: disable triggers on brightness set leds: Add mail LED support for "Clevo D400P"
Diffstat (limited to 'Documentation')
1 files changed, 9 insertions, 3 deletions
diff --git a/Documentation/leds-class.txt b/Documentation/leds-class.txt
index 56757c751d6f..18860ad9935a 100644
--- a/Documentation/leds-class.txt
+++ b/Documentation/leds-class.txt
@@ -19,6 +19,12 @@ optimises away.
Complex triggers whilst available to all LEDs have LED specific
parameters and work on a per LED basis. The timer trigger is an example.
+The timer trigger will periodically change the LED brightness between
+LED_OFF and the current brightness setting. The "on" and "off" time can
+be specified via /sys/class/leds/<device>/delay_{on,off} in milliseconds.
+You can change the brightness value of a LED independently of the timer
+trigger. However, if you set the brightness value to LED_OFF it will
+also disable the timer trigger.
You can change triggers in a similar manner to the way an IO scheduler
is chosen (via /sys/class/leds/<device>/trigger). Trigger specific
@@ -63,9 +69,9 @@ value if it is called with *delay_on==0 && *delay_off==0 parameters. In
this case the driver should give back the chosen value through delay_on
and delay_off parameters to the leds subsystem.
-Any call to the brightness_set() callback function should cancel the
-previously programmed hardware blinking function so setting the brightness
-to 0 can also cancel the blinking of the LED.
+Setting the brightness to zero with brightness_set() callback function
+should completely turn off the LED and cancel the previously programmed
+hardware blinking function, if any.
Known Issues