Re: [PATCH v5 3/3] arm64: dts: qcom: x1e78100-t14s: Add thermal zones for keyboard skin and charging sensors

[Dmitry Baryshkov]

On Mon, Jul 06, 2026 at 08:46:48PM +0200, Daniel Lezcano wrote:
> The Lenovo ThinkPad T14s embedded controller exposes several platform
> temperature sensors that are already used by the firmware for thermal
> management.
> 
> Expose the EC as a thermal sensor provider and describe the keyboard
> skin and charging circuitry sensors as thermal zones in the device
> tree.
> 
> The keyboard thermal zone defines passive and hot trip points, while
> the charging thermal zone also associates a cooling map with the CPU
> clusters, allowing the generic thermal framework to apply CPU
> throttling when the charging circuitry temperature exceeds the passive
> threshold.
> 
> This integrates the EC temperature sensors with the Linux thermal
> framework and enables platform thermal management using standard
> thermal zone definitions.
> 
> The EC protocol currently does not provide a mechanism to program trip
> points from Linux. Consequently, the thermal zones rely on periodic
> polling to detect threshold crossings.
> 
> Using the charging circuitry temperature for thermal mitigation provides
> a conservative approximation of the platform thermal state and prevents
> the platform from reaching critical temperatures under sustained heavy
> CPU load.
> 
> Without this change the platform reaches a critical thermal condition
> and resets under heavy load.
> 
> Reviewed-by: Konrad Dybcio <konrad.dybcio@xxxxxxxxxxxxxxxx>
> Tested-by: Neil Armstrong <neil.armstrong@xxxxxxxxxx> # on T14s OLED
> Signed-off-by: Daniel Lezcano <daniel.lezcano@xxxxxxxxxxxxxxxx>
> ---
>  .../qcom/x1e78100-lenovo-thinkpad-t14s.dtsi   | 67 ++++++++++++++++++-
>  1 file changed, 66 insertions(+), 1 deletion(-)

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxxxxxxxx>

> 
-- 
With best wishes
Dmitry