[PATCH v6 0/7] mfd: macsmc: add rtc, hwmon and hid subdevices

James Calligeros
2025-12-15T09:38:20Z

Hi all,

This series adds support for the remaining SMC subdevices. These are the
RTC, hwmon, and HID devices. They are being submitted together as the RTC
and hwmon drivers both require changes to the SMC DT schema.

The RTC driver is responsible for getting and setting the system clock,
and requires an NVMEM cell. This series replaces Sven's original RTC driver
submission [1].

The hwmon function is an interesting one. While each Apple Silicon device
exposes pretty similar sets of sensors, these all seem to be paired to
different SMC keys in the firmware interface. This is true even when the
sensors are on the SoC. For example, an M1 MacBook Pro will use different
keys to access the LITTLE core temperature sensors to an M1 Mac mini. This
necessitates describing which keys correspond to which sensors for each
device individually, and populating the hwmon structs at runtime. We do
this with a node in the device tree. This series includes only the keys
for sensors which we know to be common to all devices. The SMC is also
responsible for monitoring and controlling fan speeds on systems with fans,
which we expose via the hwmon driver.

The SMC also handles the hardware power button and lid switch. Power
button presses and lid opening/closing are emitted as HID events, so we
add an input subdevice to handle them.

Since there are no real dependencies between the components of this series,
it should be fine for each subsystem to take the relevant patches through
their trees. The mfd one-liners should be taken in order to avoid trivial
conflicts.

Regards,

James

[1] https://lore.kernel.org/asahi/CAEg-Je84XxLWH7vznQmPRfjf6GxWOu75ZetwN7AdseAwfMLLrQ@mail.gmail.com/T/#t
[2] https://lore.kernel.org/asahi/20251106140050.GQ8064@google.com/

---
Changes in v6:
- Rebase onto 6.19-rc1, dropping already merged commits
- Link to v5: https://lore.kernel.org/r/20251112-macsmc-subdevs-v5-0-728e4b91fe81@gmail.com

Changes in v5:
- Drop inadvertent mfd core includes in rtc and input drivers
- Link to v4: https://lore.kernel.org/r/20251025-macsmc-subdevs-v4-0-374d5c9eba0e@gmail.com

Changes in v4:
- Added Rob's R-b to hwmon Devicetree schema
- Added missing include to hwmon driver
- Dropped superfluous dev_info() from hwmon probe
- Added Guenter's A-b to hwmon driver
- Renamed INPUT_MACSMC_INPUT to INPUT_MACSMC
- Dropped leftover mention of HID in input driver
- Reinstated input driver MODULE_ALIAS
- Trigger a hard wakeup on power button/lid switch when coming out of
s2idle
- Suppress KEY_POWER event on wakeup to prevent an immediate shutdown
when waking up
- Squashed hwmon Devicetree commits into one
- Link to v3: https://lore.kernel.org/r/20251007-macsmc-subdevs-v3-0-d7d3bfd7ae02@gmail.com

Changes in v3:
- Renamed macsmc-hid to macsmc-input
- Switched to pm_wakeup_event in macsmc-input
- macsmc-input now configures its capabilities before registering the device
- Renamed macsmc_hwmon to macsmc-hwmon
- Dropped module aliases in macsmc-input and macsmc_hwmon
- Introduced new SMC FourCC macro to silence GCC errors
- Condensed hwmon binding using $defs
- Made label property optional for hwmon sensors
- Fixed incorrect hwmon is_visible implementation
- Dropped 64-bit math from SMC float ops
- Fixed incorrect use of error numbers in hwmon driver
- Replaced a number of non-fatal dev_errs with dev_dbgs in hwmon driver
- Added hwmon driver documentation
- Added hwmon subdevice directly to the DT SMC node
- Included "common" hwmon sensors in SoC .dtsi files
- Fixed typo in hwmon-common.dtsi
- Added Neal's R-b to series
- Added required nodes to t602x Devicetrees
- Link to v2: https://lore.kernel.org/r/20250827-macsmc-subdevs-v2-0-ce5e99d54c28@gmail.com

Changes in v2:
- Added Rob's R-b tag to RTC DT binding
- Removed redundant nesting from hwmon DT binding
- Dedpulicated property definitions in hwmon DT schema
- Made label a required property for hwmon DT nodes
- Clarified semantics in hwmon DT schema definitions
- Split mfd tree changes into separate commits
- Fixed numerous style errors in hwmon driver
- Removed log messages sysfs read/write functions in hwmon driver
- Removed ignored errors from hwmon driver
- Removed uses of dev_err for non-errors in hwmon driver
- Made it more obvious that a number of hwmon fan properties are optional
- Modified hwmon driver to reflect DT schema changes
- Added compatible property to hwmon node
- Link to v1: https://lore.kernel.org/r/20250819-macsmc-subdevs-v1-0-57df6c3e5f19@gmail.com

---
Hector Martin (1):
input: macsmc-input: New driver to handle the Apple Mac SMC buttons/lid

James Calligeros (5):
dt-bindings: hwmon: Add Apple System Management Controller hwmon schema
mfd: macsmc: Wire up Apple SMC RTC subdevice
mfd: macsmc: Wire up Apple SMC hwmon subdevice
mfd: macsmc: Wire up Apple SMC input subdevice
arm64: dts: apple: t8103, t8112, t60xx: Add hwmon SMC subdevice

Sven Peter (1):
arm64: dts: apple: t8103,t60xx,t8112: Add SMC RTC node

.../bindings/hwmon/apple,smc-hwmon.yaml | 86 ++++++++++
.../bindings/mfd/apple,smc.yaml | 36 +++++
MAINTAINERS | 2 +
.../boot/dts/apple/hwmon-common.dtsi | 33 ++++
.../boot/dts/apple/hwmon-fan-dual.dtsi | 22 +++
arch/arm64/boot/dts/apple/hwmon-fan.dtsi | 17 ++
.../boot/dts/apple/hwmon-laptop.dtsi | 33 ++++
.../boot/dts/apple/hwmon-mac-mini.dtsi | 15 ++
.../arm64/boot/dts/apple/t6001-j375c.dts | 2 +
arch/arm64/boot/dts/apple/t6001.dtsi | 2 +
.../arm64/boot/dts/apple/t6002-j375d.dts | 2 +
.../arm64/boot/dts/apple/t600x-die0.dtsi | 10 ++
.../boot/dts/apple/t600x-j314-j316.dtsi | 3 +
.../arm64/boot/dts/apple/t602x-die0.dtsi | 10 ++
arch/arm64/boot/dts/apple/t8103-j274.dts | 2 +
arch/arm64/boot/dts/apple/t8103-j293.dts | 3 +
arch/arm64/boot/dts/apple/t8103-j313.dts | 2 +
arch/arm64/boot/dts/apple/t8103-j456.dts | 2 +
arch/arm64/boot/dts/apple/t8103-j457.dts | 2 +
arch/arm64/boot/dts/apple/t8103.dtsi | 11 ++
arch/arm64/boot/dts/apple/t8112-j413.dts | 2 +
arch/arm64/boot/dts/apple/t8112-j473.dts | 2 +
arch/arm64/boot/dts/apple/t8112-j493.dts | 3 +
arch/arm64/boot/dts/apple/t8112.dtsi | 11 ++
drivers/input/misc/Kconfig | 11 ++
drivers/input/misc/Makefile | 1 +
drivers/input/misc/macsmc-input.c | 207 +++++++++++++++++++++++++
drivers/mfd/macsmc.c | 3 +
28 files changed, 535 insertions(+)
---
base-commit: 8f0b4cce4481fb22653697cced8d0d04027cb1e8
change-id: 20250816-macsmc-subdevs-87032c017d0c

Best regards,
--
James Calligeros <jcalligeros99@gmail.com>