kernel/linux.git/drivers/mfd/macsmc.c, branch v6.18.22

mfd: macsmc: Initialize mutex

2026-03-04T12:21:12+00:00

[ Upstream commit 414f65d6736342c77d4ec5e7373039f4a09250dd ] Initialize struct apple_smc's mutex in apple_smc_probe(). Using the mutex uninitialized surprisingly resulted only in occasional NULL pointer dereferences in apple_smc_read() calls from the probe() functions of sub devices. Cc: stable@vger.kernel.org Fixes: e038d985c9823 ("mfd: Add Apple Silicon System Management Controller") Signed-off-by: Janne Grunau Reviewed-by: Sven Peter Reviewed-by: Neal Gompa Link: https://patch.msgid.link/20251231-macsmc-mutex_init-v2-1-5818c9dc9b29@jannau.net Signed-off-by: Lee Jones Signed-off-by: Sasha Levin

mfd: macsmc: Add "apple,t8103-smc" compatible

2025-10-01T09:28:38+00:00

After discussion with the devicetree maintainers we agreed to not extend lists with the generic compatible "apple,smc" anymore [1]. Use "apple,t8103-smc" as base compatible as it is the SoC the driver and bindings were written for. [1]: https://lore.kernel.org/asahi/12ab93b7-1fc2-4ce0-926e-c8141cfe81bf@kernel.org/ Signed-off-by: Janne Grunau Link: https://lore.kernel.org/r/20250828-dt-apple-t6020-v1-18-507ba4c4b98e@jannau.net Signed-off-by: Lee Jones

mfd: macsmc: Remove error prints for devm_add_action_or_reset()

2025-10-01T09:28:19+00:00

When `devm_add_action_or_reset()` fails, it is due to a failed memory allocation and will thus return `-ENOMEM`. `dev_err_probe()` doesn't do anything when error is `-ENOMEM`. Therefore, remove the useless call to `dev_err_probe()` when `devm_add_action_or_reset()` fails, and just return the value instead. Signed-off-by: Waqar Hameed Reviewed-by: Sven Peter Link: https://lore.kernel.org/r/pnd8qjym7td.a.out@axis.com Signed-off-by: Lee Jones

mfd: Add Apple Silicon System Management Controller

2025-07-24T08:47:33+00:00

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 Signed-off-by: Hector Martin Reviewed-by: Alyssa Rosenzweig Reviewed-by: Neal Gompa Signed-off-by: Sven Peter Link: https://lore.kernel.org/r/20250610-smc-6-15-v7-5-556cafd771d3@kernel.org Signed-off-by: Lee Jones