From 5f634c6527249275df4199a294ee9cec2f3ff3b1 Mon Sep 17 00:00:00 2001 From: Corentin Chary Date: Fri, 28 Aug 2009 12:56:45 +0000 Subject: [PATCH] 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 Signed-off-by: Corentin Chary Signed-off-by: Len Brown --- Documentation/ABI/testing/sysfs-class-led | 28 +++++++++++++++++++++++ Documentation/leds-class.txt | 9 ++++---- 2 files changed, 33 insertions(+), 4 deletions(-) create mode 100644 Documentation/ABI/testing/sysfs-class-led 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//brightness +Date: March 2006 +KernelVersion: 2.6.17 +Contact: Richard Purdie +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//max_brightness. + +What: /sys/class/leds//max_brightness +Date: March 2006 +KernelVersion: 2.6.17 +Contact: Richard Purdie +Description: + Maximum brightness level for this led, default is 255 (LED_FULL). + +What: /sys/class/leds//trigger +Date: March 2006 +KernelVersion: 2.6.17 +Contact: Richard Purdie +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/ 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