Linux Backlight class digital display backlights

A digital display which has a backlight may have a Linux backlight driver which provides a sysfs API. Typically these are implemented via PWM signals allowing a variable brightness or a GPIO signal allowing a simple on/off.

Mapping A backlight driver to a PWM, GPIO, or other controller is done in the board support file or in the case of more modern kernels such as Ventana in the device-tree. See the backlight node in the gw54xx device-tree for example.

To list available backlight controllers:

ls /sys/class/backlight

To see current/available brightness values:

cat /sys/class/backlight/*/brightness # current brightness
cat /sys/class/backlight/*/max_brightness # max brightness

To set brightness (to a value equal or less than max_brightness)

echo 0 > /sys/class/backlight/*/brightness # turn off backlight


Other References

Here are some other useful references from our wiki:

Last modified 5 years ago Last modified on 01/15/2018 05:44:24 PM