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1What: /sys/class/leds/<led>/brightness2Date: March 20063KernelVersion: 2.6.174Contact: Richard Purdie <rpurdie@rpsys.net>5Description:6 Set the brightness of the LED.7 8 Most LEDs don't have hardware brightness support, so will9 just be turned on for non-zero brightness settings.10 11 .. Note::12 13 For multicolor LEDs, writing to this file will update all14 LEDs within the group to a calculated percentage of what15 each color LED intensity is set to.16 17 The percentage is calculated for each grouped LED via18 the equation below::19 20 led_brightness = brightness * multi_intensity/max_brightness21 22 For additional details please refer to23 Documentation/leds/leds-class-multicolor.rst.24 25 The value is between 0 and26 /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 the31 top brightness trigger is going to use.32 33 34 35What: /sys/class/leds/<led>/max_brightness36Date: March 200637KernelVersion: 2.6.1738Contact: 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, this43 should be 1.44 45What: /sys/class/leds/<led>/brightness_hw_changed46Date: January 201747KernelVersion: 4.1148Description:49 Last hardware set brightness level for this LED. Some LEDs50 may be changed autonomously by hardware/firmware. Only LEDs51 where this happens and the driver can detect this, will have52 this file.53 54 This file supports poll() to detect when the hardware changes55 the brightness.56 57 Reading this file will return the last brightness level set58 by the hardware, this may be different from the current59 brightness. Reading this file when no hw brightness change60 event has happened will return an ENODATA error.61 62What: /sys/class/leds/<led>/trigger63Date: March 200664KernelVersion: 2.6.1765Contact: Richard Purdie <rpurdie@rpsys.net>66Description:67 Set the trigger for this LED. A trigger is a kernel based source68 of LED events.69 70 You can change triggers in a similar manner to the way an IO71 scheduler is chosen. Trigger specific parameters can appear in72 /sys/class/leds/<led> once a given trigger is selected. For73 their documentation see `sysfs-class-led-trigger-*`.74 75What: /sys/class/leds/<led>/inverted76Date: January 201177KernelVersion: 2.6.3878Contact: Richard Purdie <rpurdie@rpsys.net>79Description:80 Invert the LED on/off state. This parameter is specific to81 gpio and backlight triggers. In case of the backlight trigger,82 it is useful when driving a LED which is intended to indicate83 a device in a standby like state.84