linux-kernel - Re: [PATCH v5 06/11] hwmon: Add Apple Silicon SMC hwmon driver

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Message-ID: <7a445358-ce9e-4180-99dd-1a771c8ffa98@roeck-us.net>
Date: Mon, 17 Nov 2025 11:00:48 -0800
From: Guenter Roeck <linux@...ck-us.net>
To: James Calligeros <jcalligeros99@...il.com>
Cc: Sven Peter <sven@...nel.org>, Janne Grunau <j@...nau.net>,
	Alyssa Rosenzweig <alyssa@...enzweig.io>,
	Neal Gompa <neal@...pa.dev>, Lee Jones <lee@...nel.org>,
	Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>,
	Alexandre Belloni <alexandre.belloni@...tlin.com>,
	Jean Delvare <jdelvare@...e.com>,
	Dmitry Torokhov <dmitry.torokhov@...il.com>,
	Jonathan Corbet <corbet@....net>, asahi@...ts.linux.dev,
	linux-arm-kernel@...ts.infradead.org, devicetree@...r.kernel.org,
	linux-kernel@...r.kernel.org, linux-rtc@...r.kernel.org,
	linux-hwmon@...r.kernel.org, linux-input@...r.kernel.org,
	linux-doc@...r.kernel.org
Subject: Re: [PATCH v5 06/11] hwmon: Add Apple Silicon SMC hwmon driver

On Wed, Nov 12, 2025 at 09:16:52PM +1000, James Calligeros wrote:
> 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: Neal Gompa <neal@...pa.dev>
> Acked-by: Guenter Roeck <linux@...ck-us.net>
> Co-developed-by: Janne Grunau <j@...nau.net>
> Signed-off-by: Janne Grunau <j@...nau.net>
> Signed-off-by: James Calligeros <jcalligeros99@...il.com>

Applied to hwmon-next.

Note that I can not apply the devicetree patch (2/11), presumably since it depends
on the first patch of the series.

Guenter