linux-kernel - Re: [PATCH v2] hwmon: Add thermal sensor driver for Surface Aggregator Module

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Message-ID: <4464d0f5-1a40-40b9-8d53-7f0d75b9d062@gmail.com>
Date: Sat, 10 Aug 2024 03:04:20 +0200
From: Maximilian Luz <luzmaximilian@...il.com>
To: Konrad Dybcio <konradybcio@...nel.org>, Guenter Roeck <linux@...ck-us.net>
Cc: Jean Delvare <jdelvare@...e.com>, Hans de Goede <hdegoede@...hat.com>,
 Ivor Wanders <ivor@...nders.net>, linux-kernel@...r.kernel.org,
 linux-hwmon@...r.kernel.org
Subject: Re: [PATCH v2] hwmon: Add thermal sensor driver for Surface
 Aggregator Module

On 8/10/24 1:35 AM, Konrad Dybcio wrote:
> On 5.08.2024 1:08 AM, Maximilian Luz wrote:
>> Some of the newer Microsoft Surface devices (such as the Surface Book
>> 3 and Pro 9) have thermal sensors connected via the Surface Aggregator
>> Module (the embedded controller on those devices). Add a basic driver
>> to read out the temperature values of those sensors.
>>
>> The EC can have up to 16 thermal sensors connected via a single
>> sub-device, each providing temperature readings and a label string.
>>
>> Link: https://github.com/linux-surface/surface-aggregator-module/issues/59
>> Reviewed-by: Hans de Goede <hdegoede@...hat.com>
>> Co-developed-by: Ivor Wanders <ivor@...nders.net>
>> Signed-off-by: Ivor Wanders <ivor@...nders.net>
>> Signed-off-by: Maximilian Luz <luzmaximilian@...il.com>
>>
>> ---
> 
> Gave it a shot on SL7, some names are repeated and one sensor is
> totally busted
> 
> /sys/class/hwmon/hwmon66/name:surface_thermal
> /sys/class/hwmon/hwmon66/temp10_input:32200
> /sys/class/hwmon/hwmon66/temp10_label:I_RTS2
> /sys/class/hwmon/hwmon66/temp11_input:31600
> /sys/class/hwmon/hwmon66/temp11_label:I_RTS3
> /sys/class/hwmon/hwmon66/temp12_input:38000
> /sys/class/hwmon/hwmon66/temp12_label:I_RTS4
> /sys/class/hwmon/hwmon66/temp1_input:43900
> /sys/class/hwmon/hwmon66/temp1_label:I_RTS1
> /sys/class/hwmon/hwmon66/temp2_input:44000
> /sys/class/hwmon/hwmon66/temp2_label:I_RTS2
> /sys/class/hwmon/hwmon66/temp3_input:47300
> /sys/class/hwmon/hwmon66/temp3_label:I_RTS3
> /sys/class/hwmon/hwmon66/temp4_input:-273100
> /sys/class/hwmon/hwmon66/temp4_label:I_RTS4
> /sys/class/hwmon/hwmon66/temp5_input:31300
> /sys/class/hwmon/hwmon66/temp5_label:I_RTS5
> /sys/class/hwmon/hwmon66/temp9_input:37100
> /sys/class/hwmon/hwmon66/temp9_label:I_RTS1

Hmm, on the SPX it looks like this:

I_RTS1:       +31.9°C
I_RTS2:       +31.3°C
I_RTS3:       +31.4°C
I_RTS4:       +28.3°C
I_RTS5:       +29.3°C
I_RTS6:       +29.3°C
I_RTS7:       +29.3°C
I_RTS8:       +29.3°C
VTS1:         +30.2°C
VTS2:          +0.0°C
VTS3:          +0.0°C
VTS4:          +0.0°C
VTS5:          +0.0°C

So VTS2-5 seem like they may not actually be connected, but the rest at
least look somewhat sensible. I'd probably still keep the names as they
at least might give an indication what the sensors could be for.

But there's a good chance that we're missing something on how MS
envisions these sensors to work exactly.

Regards,
Max