1What:		/sys/class/leds/<led>/brightness
 2Date:		March 2006
 3KernelVersion:	2.6.17
 4Contact:	Richard Purdie <rpurdie@rpsys.net>
 5Description:
 6		Set the brightness of the LED.
 7
 8		Most LEDs don't have hardware brightness support, so will
 9		just be turned on for non-zero brightness settings.
10
11		.. Note::
12
13		  For multicolor LEDs, writing to this file will update all
14		  LEDs within the group to a calculated percentage of what
15		  each color LED intensity is set to.
16
17		  The percentage is calculated for each grouped LED via
18		  the equation below::
19
20		    led_brightness = brightness * multi_intensity/max_brightness
21
22		  For additional details please refer to
23		  Documentation/leds/leds-class-multicolor.rst.
24
25		The value is between 0 and
26		/sys/class/leds/<led>/max_brightness.
27
28		Writing 0 to this file clears active trigger.
29
30		Writing non-zero to this file while trigger is active changes the
31		top brightness trigger is going to use.
32
33
34
35What:		/sys/class/leds/<led>/max_brightness
36Date:		March 2006
37KernelVersion:	2.6.17
38Contact:	Richard Purdie <rpurdie@rpsys.net>
39Description:
40		Maximum brightness level for this LED, default is 255 (LED_FULL).
41
42		If the LED does not support different brightness levels, this
43		should be 1.
44
45What:		/sys/class/leds/<led>/brightness_hw_changed
46Date:		January 2017
47KernelVersion:	4.11
48Description:
49		Last hardware set brightness level for this LED. Some LEDs
50		may be changed autonomously by hardware/firmware. Only LEDs
51		where this happens and the driver can detect this, will have
52		this file.
53
54		This file supports poll() to detect when the hardware changes
55		the brightness.
56
57		Reading this file will return the last brightness level set
58		by the hardware, this may be different from the current
59		brightness. Reading this file when no hw brightness change
60		event has happened will return an ENODATA error.
61
62What:		/sys/class/leds/<led>/trigger
63Date:		March 2006
64KernelVersion:	2.6.17
65Contact:	Richard Purdie <rpurdie@rpsys.net>
66Description:
67		Set the trigger for this LED. A trigger is a kernel based source
68		of LED events.
69
70		You can change triggers in a similar manner to the way an IO
71		scheduler is chosen. Trigger specific parameters can appear in
72		/sys/class/leds/<led> once a given trigger is selected. For
73		their documentation see `sysfs-class-led-trigger-*`.
74
75What:		/sys/class/leds/<led>/inverted
76Date:		January 2011
77KernelVersion:	2.6.38
78Contact:	Richard Purdie <rpurdie@rpsys.net>
79Description:
80		Invert the LED on/off state. This parameter is specific to
81		gpio and backlight triggers. In case of the backlight trigger,
82		it is useful when driving a LED which is intended to indicate
83		a device in a standby like state.

 1What:		/sys/class/leds/<led>/brightness
 2Date:		March 2006
 3KernelVersion:	2.6.17
 4Contact:	Richard Purdie <rpurdie@rpsys.net>
 5Description:
 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
 
 
16What:		/sys/class/leds/<led>/max_brightness
17Date:		March 2006
18KernelVersion:	2.6.17
19Contact:	Richard Purdie <rpurdie@rpsys.net>
20Description:
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
26What:		/sys/class/leds/<led>/brightness_hw_changed
27Date:		January 2017
28KernelVersion:	4.11
29Description:
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
43What:		/sys/class/leds/<led>/trigger
44Date:		March 2006
45KernelVersion:	2.6.17
46Contact:	Richard Purdie <rpurdie@rpsys.net>
47Description:
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
55What:		/sys/class/leds/<led>/inverted
56Date:		January 2011
57KernelVersion:	2.6.38
58Contact:	Richard Purdie <rpurdie@rpsys.net>
59Description:
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.