mfd: Add Apple Silicon System Management Controller

The System Management Controller (SMC) on Apple Silicon machines is a
piece of hardware that exposes various functionalities such as
temperature sensors, voltage/power meters, shutdown/reboot handling,
GPIOs and more.

Communication happens via a shared mailbox using the RTKit protocol
which is also used for other co-processors. The SMC protocol then allows
reading and writing many different keys which implement the various
features. The MFD core device handles this protocol and exposes it
to the sub-devices.

Some of the sub-devices are potentially also useful on pre-M1 Apple
machines and support for SMCs on these machines can be added at a later
time.

Co-developed-by: Hector Martin <marcan@marcan.st>
Signed-off-by: Hector Martin <marcan@marcan.st>
Reviewed-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Reviewed-by: Neal Gompa <neal@gompa.dev>
Signed-off-by: Sven Peter <sven@kernel.org>
Link: https://lore.kernel.org/r/20250610-smc-6-15-v7-5-556cafd771d3@kernel.org
Signed-off-by: Lee Jones <lee@kernel.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index 79495f9f3457..f7bdedd5a66d 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -21,6 +21,7 @@ obj-$(CONFIG_MFD_CS42L43_SDW)	+= cs42l43-sdw.o
 obj-$(CONFIG_MFD_ENE_KB3930)	+= ene-kb3930.o
 obj-$(CONFIG_MFD_EXYNOS_LPASS)	+= exynos-lpass.o
 obj-$(CONFIG_MFD_GATEWORKS_GSC)	+= gateworks-gsc.o
+obj-$(CONFIG_MFD_MACSMC)	+= macsmc.o
 
 obj-$(CONFIG_MFD_TI_LP873X)	+= lp873x.o
 obj-$(CONFIG_MFD_TI_LP87565)	+= lp87565.o