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. 64