While the Linux v6.17 merge window only wrapped up earlier this month, Apple Silicon DeviceTree “DT” updates have already begun queuing for the Linux 6.18 merge window that will happen in October.
Due to the alignment of work between the different development trees, these Apple SoC DT changes missed the recent 6.17 merge window. Sven Peter who has been working on upstreaming the relevant Asahi Linux changes to the mainline Linux kernel explained that these patches could have made v6.17 but the DT binding changes were only picked up after he already sent out his pull request that in turn was already very late.
These DT patches add the System Management Controller (SMC) nodes for the Apple M1 and M2 SoCs, including the new PMU GPIO controller and reboot sub-nodes. These are the DT additions for the Apple SMC driver added to Linux 6.17 notably for allowing modern Macs to actually reboot under Linux with the mainline kernel.
Sven Peter also noted those Apple SMC nodes are also needed for later enabling the power GPIO line for the WiFi board.
These early Apple SOC DT changes for Linux 6.18 also add the i2c nodes for the older Apple A7 through A11 SoCs.
More details on these early Linux 6.18 changes via this pull request