On Mon, 15 Dec 2025 19:37:45 +1000, James Calligeros wrote:

Apple Silicon devices integrate a vast array of sensors, monitoring
current, power, temperature, and voltage across almost every part of
the system. The sensors themselves are all connected to the System
Management Controller (SMC). The SMC firmware exposes the data
reported by these sensors via its standard FourCC-based key-value
API. The SMC is also responsible for monitoring and controlling any
fans connected to the system, exposing them in the same way.

For reasons known only to Apple, each device exposes its sensors with
an almost totally unique set of keys. This is true even for devices
which share an SoC. An M1 Mac mini, for example, will report its core
temperatures on different keys to an M1 MacBook Pro. Worse still, the
SMC does not provide a way to enumerate the available keys at runtime,
nor do the keys follow any sort of reasonable or consistent naming
rules that could be used to deduce their purpose. We must therefore
know which keys are present on any given device, and which function
they serve, ahead of time.

Add a schema so that we can describe the available sensors for a given
Apple Silicon device in the Devicetree.

Reviewed-by: Neal Gompa <neal@gompa.dev>
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: James Calligeros <redacted>
---
 .../bindings/hwmon/apple,smc-hwmon.yaml  | 86 +++++++++++++++++++++++++
 .../bindings/mfd/apple,smc.yaml          | 36 +++++++++++
 MAINTAINERS                              |  1 +
 3 files changed, 123 insertions(+)

My bot found errors running 'make dt_binding_check' on your patch:

yamllint warnings/errors:
./Documentation/devicetree/bindings/hwmon/apple,smc-hwmon.yaml:73:1: [warning] too many blank lines (2 > 1) (empty-lines)

dtschema/dtc warnings/errors:

doc reference errors (make refcheckdocs):

See https://patchwork.kernel.org/project/devicetree/patch/20251215-macsmc-subdevs-v6-1-0518cb5f28ae@gmail.com

The base for the series is generally the latest rc1. A different dependency
should be noted in *this* patch.

If you already ran 'make dt_binding_check' and didn't see the above
error(s), then make sure 'yamllint' is installed and dt-schema is up to
date:

pip3 install dtschema --upgrade

Please check and re-submit after running the above command yourself. Note
that DT_SCHEMA_FILES can be set to your schema file to speed up checking
your schema. However, it must be unset to test all examples with your schema.