Re: [PATCH v1 1/3] drivers/platform: lenovo-t14s-ec: Add hwmon support for temperatures and fan speed

[Konrad Dybcio]

On 6/28/26 4:02 PM, Guenter Roeck wrote:
> On 6/28/26 06:50, Sebastian Reichel wrote:
>> Hi,
>>
>> On Wed, Jun 24, 2026 at 11:08:23PM +0200, Daniel Lezcano wrote:
>>> Expose the Lenovo ThinkPad T14s EC environmental sensors through
>>> the hwmon subsystem.
>>>
>>> The driver now registers a hwmon device providing access to six EC
>>> temperature sensors corresponding to the SoC, keyboard area, base
>>> cover, PMIC/charging circuitry, QTM module and SSD. Sensor labels
>>> are exported to allow user space to identify each measurement.
>>>
>>> Additionally, expose the system fan speed by reading the fan RPM
>>> registers from the embedded controller.
>>>
>>> This allows standard monitoring tools such as lm-sensors to report
>>> platform temperatures and fan speed.
>>>
>>> Signed-off-by: Daniel Lezcano daniel.lezcano@xxxxxxxxxxxxxxxx
>>> ---
>>
>> I gave this a try and for me the fan data is always 65535 (i.e. -1):
>>
>> $ cat /sys/class/hwmon/hwmon66/{name,fan1_input}
>> t14s_ec
>> 65535
>>
>> This is with the fan running:
>>
>> $ cat /sys/class/hwmon/hwmon57/{name,fan1_input}
>> fan-controller
>> 2564
>>
> 
> Not really my concern, but those names really add zero value,
> and I would argue that they do not "allow user space to identify
> each measurement".
> 
> Also, do you really have 66 hwmon devices on those systems ?
> Seems unusual.

There's a couple dozen thermal sensors on the SoC and each one is
registered with a thermal zone, plus a couple here and there for
other onboard peripherals (PMICs and whatnot)

Konrad