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

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

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@linaro.org> # 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