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: e038d985c9 ("mfd: Add Apple Silicon System Management Controller")
Signed-off-by: Janne Grunau <j@jannau.net>
Reviewed-by: Sven Peter <sven@kernel.org>
Reviewed-by: Neal Gompa <neal@gompa.dev>
Link: https://patch.msgid.link/20251231-macsmc-mutex_init-v2-1-5818c9dc9b29@jannau.net
Signed-off-by: Lee Jones <lee@kernel.org>
Mark the write buffer arguments in apple_smc_write(), apple_smc_rw(),
and apple_smc_write_atomic() as const. These functions do not modify
the data provided by the caller, so the parameters should be const
qualified.
Signed-off-by: Atharva Tiwari <atharvatiwarilinuxdev@gmail.com>
Reviewed-by: Sven Peter <sven@kernel.org>
Signed-off-by: Lee Jones <lee@kernel.org>
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 <waqar.hameed@axis.com>
Reviewed-by: Sven Peter <sven@kernel.org>
Link: https://lore.kernel.org/r/pnd8qjym7td.a.out@axis.com
Signed-off-by: Lee Jones <lee@kernel.org>
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>
