More Apple M1 Bring-Up For Linux Continues: SPI, SimpleDRM, PMU

One year after Apple introduced the M1 SoC and the effort began to bring-up this Apple Silicon under Linux, the effort remains ongoing and more code is inching closer to the mainline kernel.

Recently work got underway on the new M1 Pro / M1 Max for Linux that fortunately isn't too invasive for changes over the original M1. With the Linux 5.16 kernel there is the M1 PCIe driver, Apple CD321X USB, and then ahead for Linux 5.17 already queued up is an Apple PMGR driver, PCIe clock gating, and DT updates.

The latest out this weekend are the patches for an Apple SPI controller driver. This SPI driver is based on SiFive's driver and was adapted to work with Apple SoCs. The driver has been successfully tested with a patched version of the Apple SPI keyboard driver for Linux, but the Asahi Linux crew says they are going to be writing a new driver for the keyboard.

Also posted today was the v3 patches getting the SimpleDRM support. This series simply gets the SimpleDRM code working nicely as an alternative to using SimpleFB. Ultimately the Apple M1 Linux developers are still working towards a proper full-featured Direct Rendering Manager driver to go along with Mesa drivers for OpenGL/Vulkan, but that is all still a big work-in-progress effort.

Rounding out the recent Apple M1 activity on the Linux kernel mailing list are recent Apple PMU patches.

Everything continues moving forward for the project and will be interesting to see how well it all works out once there is a convenient Asahi Linux installer and the 3D graphics support begins to take shape for a usable daily desktop/laptop system.