Janne Grunau <j@jannau.net> says:
The Linux device trees for Apple silicon devices cover now most of the
hardware as u-boot's internal device trees for M1 devices. Linux has in
addition device trees M2 and M1 and M2 Pro/Max/Ultra devices which were
never added in u-boot.
The most common use case for u-boot on Apple silicon devices does not
use DTBs from u-boot but passes runtime modified device trees from an
earlier boot loader (m1n1).
This change regresses support for the SPI on M1 and M1 Pro/Max notebooks
as SPI keyboard support is not in upstream Linux. This regression is in
my opinion acceptable due to the limited use of u-boot's DTBs for these
targets.
Link: https://lore.kernel.org/r/20260507-apple-dt-upstream-v2-0-35181f2b0509@jannau.net