summaryrefslogtreecommitdiffstats
path: root/Documentation
diff options
context:
space:
mode:
authorCorentin Chary <corentincj@iksaif.net>2009-08-28 12:56:45 +0000
committerLen Brown <len.brown@intel.com>2009-08-28 15:21:12 -0400
commit5f634c6527249275df4199a294ee9cec2f3ff3b1 (patch)
tree44c2d69f6e28823a6c1c66683440d7ba2e3890a4 /Documentation
parent243ca3e401bc62e704785d215931f1a51fd53bd7 (diff)
downloadkernel-crypto-5f634c6527249275df4199a294ee9cec2f3ff3b1.tar.gz
kernel-crypto-5f634c6527249275df4199a294ee9cec2f3ff3b1.tar.xz
kernel-crypto-5f634c6527249275df4199a294ee9cec2f3ff3b1.zip
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>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/ABI/testing/sysfs-class-led28
-rw-r--r--Documentation/leds-class.txt9
2 files changed, 33 insertions, 4 deletions
diff --git a/Documentation/ABI/testing/sysfs-class-led b/Documentation/ABI/testing/sysfs-class-led
new file mode 100644
index 00000000000..9e4541d71cb
--- /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.
+
diff --git a/Documentation/leds-class.txt b/Documentation/leds-class.txt
index 6399557cdab..8fd5ca2ae32 100644
--- a/Documentation/leds-class.txt
+++ b/Documentation/leds-class.txt
@@ -1,3 +1,4 @@
+
LED handling under Linux
========================
@@ -5,10 +6,10 @@ If you're reading this and thinking about keyboard leds, these are
handled by the input subsystem and the led class is *not* needed.
In its simplest form, the LED class just allows control of LEDs from
-userspace. LEDs appear in /sys/class/leds/. The brightness file will
-set the brightness of the LED (taking a value 0-255). Most LEDs don't
-have hardware brightness support so will just be turned on for non-zero
-brightness settings.
+userspace. LEDs appear in /sys/class/leds/. The maximum brightness of the
+LED is defined in max_brightness file. The brightness file will set the brightness
+of the LED (taking a value 0-max_brightness). Most LEDs don't have hardware
+brightness support so will just be turned on for non-zero brightness settings.
The class also introduces the optional concept of an LED trigger. A trigger
is a kernel based source of led events. Triggers can either be simple or