About Kernel Documentation Linux Kernel Contact Linux Resources Linux Blog

Documentation / ABI / testing / sysfs-class-led




Custom Search

Based on kernel version 4.13.3. Page generated on 2017-09-23 13:54 EST.

1	What:		/sys/class/leds/<led>/brightness
2	Date:		March 2006
3	KernelVersion:	2.6.17
4	Contact:	Richard Purdie <rpurdie@rpsys.net>
5	Description:
6			Set the brightness of the LED. Most LEDs don't
7			have hardware brightness support, so will just be turned on for
8			non-zero brightness settings. The value is between 0 and
9			/sys/class/leds/<led>/max_brightness.
10	
11			Writing 0 to this file clears active trigger.
12	
13			Writing non-zero to this file while trigger is active changes the
14			top brightness trigger is going to use.
15	
16	What:		/sys/class/leds/<led>/max_brightness
17	Date:		March 2006
18	KernelVersion:	2.6.17
19	Contact:	Richard Purdie <rpurdie@rpsys.net>
20	Description:
21			Maximum brightness level for this LED, default is 255 (LED_FULL).
22	
23			If the LED does not support different brightness levels, this
24			should be 1.
25	
26	What:		/sys/class/leds/<led>/brightness_hw_changed
27	Date:		January 2017
28	KernelVersion:	4.11
29	Description:
30			Last hardware set brightness level for this LED. Some LEDs
31			may be changed autonomously by hardware/firmware. Only LEDs
32			where this happens and the driver can detect this, will have
33			this file.
34	
35			This file supports poll() to detect when the hardware changes
36			the brightness.
37	
38			Reading this file will return the last brightness level set
39			by the hardware, this may be different from the current
40			brightness. Reading this file when no hw brightness change
41			event has happened will return an ENODATA error.
42	
43	What:		/sys/class/leds/<led>/trigger
44	Date:		March 2006
45	KernelVersion:	2.6.17
46	Contact:	Richard Purdie <rpurdie@rpsys.net>
47	Description:
48			Set the trigger for this LED. A trigger is a kernel based source
49			of LED events.
50			You can change triggers in a similar manner to the way an IO
51			scheduler is chosen. Trigger specific parameters can appear in
52			/sys/class/leds/<led> once a given trigger is selected. For
53			their documentation see sysfs-class-led-trigger-*.
54	
55	What:		/sys/class/leds/<led>/inverted
56	Date:		January 2011
57	KernelVersion:	2.6.38
58	Contact:	Richard Purdie <rpurdie@rpsys.net>
59	Description:
60			Invert the LED on/off state. This parameter is specific to
61			gpio and backlight triggers. In case of the backlight trigger,
62			it is useful when driving a LED which is intended to indicate
63			a device in a standby like state.
Hide Line Numbers
About Kernel Documentation Linux Kernel Contact Linux Resources Linux Blog

Information is copyright its respective author. All material is available from the Linux Kernel Source distributed under a GPL License. This page is provided as a free service by mjmwired.net.