Re: [PATCH v3 0/2] Lenovo ThinkPad T14s EC thermal monitoring and thermal zone integration

[Neil Armstrong]

On 7/3/26 16:09, Neil Armstrong wrote:
> On 7/3/26 12:32, Neil Armstrong wrote:
> > On 7/1/26 12:37, Daniel Lezcano wrote:
> > > Hi,
> > >
> > > This series extends the Lenovo ThinkPad T14s embedded controller driver
> > > with environmental monitoring capabilities and integrates the exposed
> > > sensors into the Linux thermal framework.
> > >
> > > The EC provides access to several platform temperature sensors
> > > covering the SoC, keyboard area, bottom cover, charging circuitry, QTM
> > > module and SSD. These sensors are currently used by the firmware for
> > > thermal management but are not exposed to Linux.
> > >
> > > The first patch adds hwmon support for the EC temperature sensors.
> > >
> > > The second patch exposes the EC as a thermal sensor provider in the
> > > device tree and defines thermal zones for the keyboard skin
> > > temperature and the charging circuitry temperature. This allows the
> > > generic thermal framework to react to EC-reported temperatures and
> > > apply standard Linux thermal mitigation policies.
> > >
> > > As the EC protocol is not fully decoded, the passive trip points
> > > get/set actions are missing, so it is not possible to program a
> > > threshold and receive an interrupt when crossed the way up or
> > > down. Consequently, the thermal zone related to the charging circuitry
> > > is polled every two seconds until we can set the trip points in the
> > > EC.
> > >
> > > This series fixes critical thermal issues happening on this platform
> > > where a kernel compilation, or heavy workloads, lead to a system
> > > reboot.
> > >
> > > Tested on a Lenovo ThinkPad T14s Gen 6 (Snapdragon X Elite).
> > >
> > > Thanks,
> > >
> > > Daniel
> > >
> > > ---
> > >   Changelog:
> > >     v3:
> > >      - Removed event based because trip point are not yet well supported
> > >      - Added an empty line after variable declaration (Ilpo Järvinen)
> > >      - Used MILLIDEGREE_PER_DEGREE from units.h (Ilpo Järvinen)
> > >      - Made switch consistent (Ilpo Järvinen)
> > >     v2:
> > >      - Fixed patch 1 subject prefix
> > >      - Removed the fan information part
> > >      - Added HWMON_T_ALARM
> > >      - Fixed DT change description to reflect what it does really
> > >
> > > Daniel Lezcano (2):
> > >    platform: arm64: lenovo-thinkpad-t14s-ec: Add hwmon support for
> > >      temperatures
> > >    arm64: dts: qcom: x1e78100-t14s: Add thermal zones for keyboard skin
> > >      and charging sensors
> > >
> > >   .../qcom/x1e78100-lenovo-thinkpad-t14s.dtsi   |  68 ++++++++-
> > >   drivers/platform/arm64/lenovo-thinkpad-t14s.c | 130 ++++++++++++++++++
> > >   2 files changed, 197 insertions(+), 1 deletion(-)
> >
> > Tested-by: Neil Armstrong <neil.armstrong@xxxxxxxxxx> # on T14s OLED
>
> The charging sensor can go very high aswell and when cpu load is high the charging
> is throttled down, so perhaps it would be nice to also have a thermal zone for the
> charging sensors.

Ignore this sentence as there's already a charging thermal node...

Neil

> On my setup when charging the battery at 60W the charging sensor reports ~63C but
> goes up to 80C when building a kernel, but stays around ~70C if the charger is not
> connected.
>
> Neil