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

[Daniel Lezcano]

On 6/29/26 10:26, Konrad Dybcio wrote:
> 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)

Yes, the amount of sensors on the SoC is incredibility high and when 
adding the platform sensors it is even more. Here on my laptop there are 
59 thermal zones and 68 hwmon sensors.

I agree with Guenter comment. With all these sensors, from userspace it 
is painful to find out a specific sensor without going through all 
sensors name.

While testing the changes at every reboot, the sensor number changed and 
I have to find out which one it is. It is annoying.

Would it make sense to have a per-name link pointing to the 
corresponding hwmon / thermal zone directory ?