Linux 5.9 Introducing A Multi-Color LED Framework

Longtime Linux kernel developer Pavel Machek has taken over as sole maintainer of the LED subsystem. For this first pull request going into Linux 5.9 is a big addition... The multi-color LED framework code has finally been merged.

This multi-color framework for the Linux kernel has been in the works by Texas Instruments and is about exposing clusters of colored LEDs as an array to user-space that it can then adjust the brightness of said cluster using a single file write. This approach still allows controlling the intensity of individual LEDs as part of the array/cluster and the benefit of the framework is being able to do so in a single write.

This multi-color framework was worked on with the initial user being TI's lp55xx driver for their LP5521 / LP5523 / LP55231 / LP5562 LED display drivers that in turn are used by a variety of devices.

More details on the multi-color interface exposed to user-space via sysfs can be seen via this patch.

The full list of LED subsystem changes for Linux 5.9 via the pull request.