Commit 785205fd authored by James Calligeros's avatar James Calligeros Committed by Guenter Roeck
Browse files

hwmon: Add Apple Silicon SMC hwmon driver 



The System Management Controller on Apple Silicon devices is responsible
for integrating and exposing the data reported by the vast array of
hardware monitoring sensors present on these devices. It is also
responsible for fan control, and allows users to manually set fan
speeds if they so desire. Add a hwmon driver to expose current,
power, temperature, and voltage monitoring sensors, as well as
fan speed monitoring and control via the SMC on Apple Silicon devices.

The SMC firmware has no consistency between devices, even when they
share an SoC. The FourCC keys used to access sensors are almost
random. An M1 Mac mini will have different FourCCs for its CPU core
temperature sensors to an M1 MacBook Pro, for example. For this
reason, the valid sensors for a given device are specified in a
child of the SMC Devicetree node. The driver uses this information
to determine which sensors to make available at runtime.

Reviewed-by: default avatarNeal Gompa <neal@gompa.dev>
Acked-by: default avatarGuenter Roeck <linux@roeck-us.net>
Co-developed-by: default avatarJanne Grunau <j@jannau.net>
Signed-off-by: default avatarJanne Grunau <j@jannau.net>
Signed-off-by: default avatarJames Calligeros <jcalligeros99@gmail.com>
Link: https://lore.kernel.org/r/20251112-macsmc-subdevs-v5-6-728e4b91fe81@gmail.com


[groeck: Added Documentation to index]
Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
parent d5c0ae87

Documentation/hwmon/index.rst

+1 −0
Original line number Diff line number Diff line
@@ -144,6 +144,7 @@ Hardware Monitoring Kernel Drivers 
   ltc4261

   ltc4282

   ltc4286

   macsmc-hwmon

   max127

   max15301

   max16064

Documentation/hwmon/macsmc-hwmon.rst

0 → 100644
+71 −0
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.. SPDX-License-Identifier: GPL-2.0-only



Kernel driver macsmc-hwmon

==========================



Supported hardware



    * Apple Silicon Macs (M1 and up)



Author: James Calligeros <jcalligeros99@gmail.com>



Description

-----------



macsmc-hwmon exposes the Apple System Management controller's

temperature, voltage, current and power sensors, as well as

fan speed and control capabilities, via hwmon.



Because each Apple Silicon Mac exposes a different set of sensors

(e.g. the MacBooks expose battery telemetry that is not present on

the desktop Macs), sensors present on any given machine are described

via Devicetree. The driver picks these up and registers them with

hwmon when probed.



Manual fan speed is supported via the fan_control module parameter. This

is disabled by default and marked as unsafe, as it cannot be proven that

the system will fail safe if overheating due to manual fan control being

used.



sysfs interface

---------------



currX_input

    Ammeter value



currX_label

    Ammeter label



fanX_input

    Current fan speed



fanX_label

    Fan label



fanX_min

    Minimum possible fan speed



fanX_max

    Maximum possible fan speed



fanX_target

    Current fan setpoint



inX_input

    Voltmeter value



inX_label

    Voltmeter label



powerX_input

    Power meter value



powerX_label

    Power meter label



tempX_input

    Temperature sensor value



tempX_label

    Temperature sensor label

MAINTAINERS

+2 −0
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@@ -2438,12 +2438,14 @@ F: Documentation/devicetree/bindings/pwm/apple,s5l-fpwm.yaml 
F:	Documentation/devicetree/bindings/spi/apple,spi.yaml

F:	Documentation/devicetree/bindings/spmi/apple,spmi.yaml

F:	Documentation/devicetree/bindings/watchdog/apple,wdt.yaml

F:	Documentation/hwmon/macsmc-hwmon.rst

F:	arch/arm64/boot/dts/apple/

F:	drivers/bluetooth/hci_bcm4377.c

F:	drivers/clk/clk-apple-nco.c

F:	drivers/cpufreq/apple-soc-cpufreq.c

F:	drivers/dma/apple-admac.c

F:	drivers/gpio/gpio-macsmc.c

F:	drivers/hwmon/macsmc-hwmon.c

F:	drivers/pmdomain/apple/

F:	drivers/i2c/busses/i2c-pasemi-core.c

F:	drivers/i2c/busses/i2c-pasemi-platform.c

drivers/hwmon/Kconfig

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Original line number Diff line number Diff line
@@ -1174,6 +1174,18 @@ config SENSORS_LTQ_CPUTEMP 
	  If you say yes here you get support for the temperature

	  sensor inside your CPU.



config SENSORS_MACSMC_HWMON

	tristate "Apple SMC (Apple Silicon)"

	depends on MFD_MACSMC && OF

	help

	  This driver enables hwmon support for current, power, temperature,

	  and voltage sensors, as well as fan speed reporting and control

	  on Apple Silicon devices. Say Y here if you have an Apple Silicon

	  device.



	  This driver can also be built as a module. If so, the module will

	  be called macsmc-hwmon.



config SENSORS_MAX1111

	tristate "Maxim MAX1111 Serial 8-bit ADC chip and compatibles"

	depends on SPI_MASTER

drivers/hwmon/Makefile

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@@ -148,6 +148,7 @@ obj-$(CONFIG_SENSORS_LTC4260) += ltc4260.o 
obj-$(CONFIG_SENSORS_LTC4261)	+= ltc4261.o

obj-$(CONFIG_SENSORS_LTC4282)	+= ltc4282.o

obj-$(CONFIG_SENSORS_LTQ_CPUTEMP) += ltq-cputemp.o

obj-$(CONFIG_SENSORS_MACSMC_HWMON)	+= macsmc-hwmon.o

obj-$(CONFIG_SENSORS_MAX1111)	+= max1111.o

obj-$(CONFIG_SENSORS_MAX127)	+= max127.o

obj-$(CONFIG_SENSORS_MAX16065)	+= max16065.o