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

[Neil Armstrong <neil.armstrong@linaro.org>]

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@linaro.org> # on T14s OLED