Re: [PATCH] arm64: dts: qcom: x1e78100-thinkpad-t14s: Add thermal zones for PMICs

[johannes.goede@oss.qualcomm.com]

Hi all,

On 22-Sep-26 20:18, Daniel Lezcano wrote:
> Add the thermal zones for the ThinkPad T14s and describe the board
> temperature sensors exposed through the PMK8550 VADC.
> 
> The keyboard area is the main thermal constraint under sustained CPU
> load. Add a passive thermal zone for it and progressively throttle the
> three CPU groups as the temperature approaches the 53°C limit. The
> groups are activated at 49°C, 51°C and 53°C respectively, with a
> 1000 m°C hysteresis and a 500 ms passive polling interval.
> 
> The cooling maps limit each CPU cooling device to state 6, which
> corresponds to approximately 1.9 GHz. Testing showed that the system can
> sustain the workload with all three CPU clusters capped at this
> frequency while maintaining the expected performance, making it a
> suitable upper cooling state for thermal regulation.
> 
> Several configurations were evaluated while tuning the keyboard zone.
> Using a single 53°C trip for all CPUs allowed the temperature to rise
> quickly but resulted in a stable operating point around 54.3°C, about
> 1.3°C above the intended limit. Introducing staged cooling before the
> target significantly reduced the thermal overshoot. A 49/51/53°C
> configuration kept the steady-state temperature close to 53°C, while a
> later 49.5/51.5/53°C configuration improved the heating response but
> shifted the equilibrium slightly above the target. Based on these
> results, keep the earlier 49/51/53°C staging.
> 
> Also add a passive back-cover thermal zone which uses the GPU as a
> cooling device at 64°C, together with a 73°C critical shutdown trip.
> 
> Describe the remaining SMB, SDX, east and west board temperature
> sensors as monitoring-only thermal zones, and enable ADC thermal
> monitoring on the corresponding PMK8550 VADC channels.
> 
> Signed-off-by: Daniel Lezcano <daniel.lezcano@oss.qualcomm.com>
> ---
>  .../qcom/x1e78100-lenovo-thinkpad-t14s.dts    | 142 ++++++++++++++++++
>  1 file changed, 142 insertions(+)
> 
> diff --git a/arch/arm64/boot/dts/qcom/x1e78100-lenovo-thinkpad-t14s.dts b/arch/arm64/boot/dts/qcom/x1e78100-lenovo-thinkpad-t14s.dts
> index 5cc6a63d1ef6..9407868864ad 100644
> --- a/arch/arm64/boot/dts/qcom/x1e78100-lenovo-thinkpad-t14s.dts
> +++ b/arch/arm64/boot/dts/qcom/x1e78100-lenovo-thinkpad-t14s.dts

I just noticed that you're adding the thermal-zones here.

This should go to x1e78100-lenovo-thinkpad-t14s.dtsi note
the extra 'i' at the end, so that the thermal-zones will
also be used on the oled model.

Regards,

Hans




> @@ -10,6 +10,117 @@ / {
>  	compatible = "lenovo,thinkpad-t14s-lcd", "lenovo,thinkpad-t14s",
>  		     "qcom,x1e78100", "qcom,x1e80100";
>  
> +	thermal-zones {
> +		soc-thermal {
> +			thermal-sensors = <&pmk8550_vadc ADC5_GEN3_AMUX1_GPIO_100K_PU(1)>;
> +		};
> +
> +		keyboard-thermal {
> +			critical-action = "shutdown";
> +			polling-delay-passive = <500>;
> +
> +			thermal-sensors = <&pmk8550_vadc ADC5_GEN3_AMUX2_GPIO_100K_PU(1)>;
> +
> +			trips {
> +
> +				keyboard_alert0: trip-point0 {
> +					temperature = <49000>;
> +					hysteresis = <1000>;
> +					type = "passive";
> +				};
> +
> +				keyboard_alert1: trip-point1 {
> +					temperature = <51000>;
> +					hysteresis = <1000>;
> +					type = "passive";
> +				};
> +
> +				keyboard_alert2: trip-point2 {
> +					temperature = <53000>;
> +					hysteresis = <1000>;
> +					type = "passive";
> +				};
> +
> +				keyboard-critical {
> +					temperature = <73000>;
> +					hysteresis = <1000>;
> +					type = "critical";
> +				};
> +			};
> +
> +			cooling-maps {
> +				map0 {
> +					trip = <&keyboard_alert0>;
> +					cooling-device = <&cpu0 THERMAL_NO_LIMIT 6>,
> +							 <&cpu1 THERMAL_NO_LIMIT 6>,
> +							 <&cpu2 THERMAL_NO_LIMIT 6>,
> +							 <&cpu3 THERMAL_NO_LIMIT 6>;
> +				};
> +
> +				map1 {
> +					trip = <&keyboard_alert1>;
> +					cooling-device = <&cpu4 THERMAL_NO_LIMIT 6>,
> +							 <&cpu5 THERMAL_NO_LIMIT 6>,
> +							 <&cpu6 THERMAL_NO_LIMIT 6>,
> +							 <&cpu7 THERMAL_NO_LIMIT 6>;
> +				};
> +
> +				map2 {
> +					trip = <&keyboard_alert2>;
> +					cooling-device = <&cpu8 THERMAL_NO_LIMIT 6>,
> +							 <&cpu9 THERMAL_NO_LIMIT 6>,
> +							 <&cpu10 THERMAL_NO_LIMIT 6>,
> +							 <&cpu11 THERMAL_NO_LIMIT 6>;
> +
> +				};
> +			};
> +		};
> +
> +		backcover-thermal {
> +			critical-action = "shutdown";
> +			polling-delay-passive = <400>;
> +
> +			thermal-sensors = <&pmk8550_vadc ADC5_GEN3_AMUX1_THM_100K_PU(1)>;
> +
> +			trips {
> +				backcover_alert0: trip-point0 {
> +					temperature = <64000>;
> +					hysteresis = <1000>;
> +					type = "passive";
> +				};
> +
> +				backcover-critical {
> +					temperature = <73000>;
> +					hysteresis = <1000>;
> +					type = "critical";
> +				};
> +			};
> +
> +			cooling-maps {
> +				map0 {
> +					trip = <&backcover_alert0>;
> +					cooling-device = <&gpu THERMAL_NO_LIMIT THERMAL_NO_LIMIT>;
> +				};
> +			};
> +		};
> +
> +		smb-thermal {
> +			thermal-sensors = <&pmk8550_vadc ADC5_GEN3_AMUX2_THM_100K_PU(1)>;
> +		};
> +
> +		sdx-thermal {
> +			thermal-sensors = <&pmk8550_vadc ADC5_GEN3_AMUX3_THM_100K_PU(1)>;
> +		};
> +
> +		east-thermal {
> +			thermal-sensors = <&pmk8550_vadc ADC5_GEN3_AMUX4_THM_100K_PU(1)>;
> +		};
> +
> +		west-thermal {
> +			thermal-sensors = <&pmk8550_vadc ADC5_GEN3_AMUX5_THM_100K_PU(1)>;
> +		};
> +	};
> +
>  	backlight: backlight {
>  		compatible = "pwm-backlight";
>  		pwms = <&pmk8550_pwm 0 4266537>;
> @@ -35,6 +146,7 @@ vreg_edp_bl: regulator-edp-bl {
>  
>  		regulator-boot-on;
>  	};
> +
>  };
>  
>  &panel {
> @@ -58,3 +170,33 @@ edp_bl_pwm: edp-bl-pwm-state {
>  &pmk8550_pwm {
>  	status = "okay";
>  };
> +
> +&pmk8550_vadc {
> +	channel@144 {
> +		qcom,adc-tm;
> +	};
> +
> +	channel@145 {
> +		qcom,adc-tm;
> +	};
> +
> +	channel@146 {
> +		qcom,adc-tm;
> +	};
> +
> +	channel@147 {
> +		qcom,adc-tm;
> +	};
> +
> +	channel@148 {
> +		qcom,adc-tm;
> +	};
> +
> +	channel@14a {
> +		qcom,adc-tm;
> +	};
> +
> +	channel@14b {
> +		qcom,adc-tm;
> +	};
> +};