Re: [PATCH v2] arm64: dts: qcom: x1e78100-thinkpad-t14s: Add thermal zones for PMICs

[Hans de Goede]

Hi,

On 1-Oct-26 20:10, Daniel Lezcano wrote:
> Add thermal zones for the ThinkPad T14s and describe the board
> temperature sensors exposed through the PMK8550 VADC.
> 
> Add a passive thermal zone for the keyboard area, which is the main
> thermal constraint under sustained load. The EC reports a thermal alert
> at 57.85°C, so use this value as the passive trip point and allow the
> thermal framework to throttle all CPUs and the GPU when the threshold is
> reached. Use a 1000 m°C hysteresis and a 500 ms passive polling interval.
> 
> An earlier approach used staged CPU cluster throttling in an attempt to
> start thermal mitigation before reaching the target temperature. Testing
> did not show a significant improvement compared to throttling all CPUs at
> the EC thermal alert threshold. It also introduced a latency imbalance
> between the different CPU clusters, which could negatively affect
> workloads depending on where tasks are scheduled.
> 
> A more optimal solution would require a significantly more complex,
> system-wide approach, accounting for the workload distribution and the
> available power and thermal headroom across the CPU clusters and other
> devices. Such an approach would also require kernel mechanisms which are
> not currently available. Keep the thermal policy simple here and use a
> single passive trip, which at least ensures that the system is actively
> mitigated before reaching temperatures that could ultimately lead to a
> thermal shutdown.
> 
> The mitigation temperature is derived from the platform behaviour when
> using the balanced power profile available under Windows. A separate
> change will adjust this trip point dynamically according to events
> reported by the embedded controller. Name the trip
> "keyboard-ec-alert" so that the EC driver can identify the corresponding
> trip point in the device tree.
> 
> Also add a 73°C critical trip to shut the system down if the keyboard
> temperature reaches an unsafe level.
> 
> Add a thermal zone for the back cover with a 73°C critical shutdown
> trip.
> 
> Describe the SoC, SMB, SDX, east and west board temperature sensors as
> monitoring-only thermal zones.
> 
> Thermal camera measurements were also used to compare the reported
> temperatures with the physical temperature of the chassis. The measured
> values appear to primarily represent temperatures inside the enclosure
> rather than the user-contact surface temperature. No unsafe external
> surface temperature was observed during these tests, although this should
> not be considered a substitute for formal platform thermal qualification.
> 
> Finally, enable ADC thermal monitoring on the corresponding PMK8550 VADC
> channels used by these thermal zones.
> 
> Signed-off-by: Daniel Lezcano <daniel.lezcano@xxxxxxxxxxxxxxxx>

Thank you for your work in this.

> ---
>  .../qcom/x1e78100-lenovo-thinkpad-t14s.dtsi   | 105 ++++++++++++++++++
>  1 file changed, 105 insertions(+)
> 
> diff --git a/arch/arm64/boot/dts/qcom/x1e78100-lenovo-thinkpad-t14s.dtsi b/arch/arm64/boot/dts/qcom/x1e78100-lenovo-thinkpad-t14s.dtsi
> index 75ad74bcb042..5d3a0a5ead68 100644
> --- a/arch/arm64/boot/dts/qcom/x1e78100-lenovo-thinkpad-t14s.dtsi
> +++ b/arch/arm64/boot/dts/qcom/x1e78100-lenovo-thinkpad-t14s.dtsi
> @@ -20,6 +20,81 @@ / {
>  	compatible = "lenovo,thinkpad-t14s", "qcom,x1e78100", "qcom,x1e80100";
>  	chassis-type = "laptop";
>  
> +	thermal-zones {

I believe all nodes should be shorted by label, then name which is why
the first node before this was "wcd938x: audio-codec" since "audio-codec"
starts with an a.

So this should be at the end of the global nodes.


> +		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_ec_alert: keyboard-ec-alert {
> +					temperature = <57850>;
> +					hysteresis = <1000>;
> +					type = "passive";
> +				};
> +
> +				keyboard-critical {
> +					temperature = <73000>;
> +					hysteresis = <1000>;
> +					type = "critical";
> +				};
> +			};
> +
> +			cooling-maps {
> +				map0 {
> +					trip = <&keyboard_ec_alert>;
> +					cooling-device = <&cpu0 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> +							 <&cpu1 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> +							 <&cpu2 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> +							 <&cpu3 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> +							 <&cpu4 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> +							 <&cpu5 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> +							 <&cpu6 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> +							 <&cpu7 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> +							 <&cpu8 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> +							 <&cpu9 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> +							 <&cpu10 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> +							 <&cpu11 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> +							 <&gpu THERMAL_NO_LIMIT THERMAL_NO_LIMIT>;
> +				};
> +			};
> +		};
> +
> +		backcover-thermal {
> +			critical-action = "shutdown";
> +			thermal-sensors = <&pmk8550_vadc ADC5_GEN3_AMUX1_THM_100K_PU(1)>;
> +
> +			trips {
> +				backcover-critical {
> +					temperature = <73000>;
> +					hysteresis = <1000>;
> +					type = "critical";
> +				};
> +			};
> +		};
> +
> +		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)>;
> +		};
> +	};
> +
>  	wcd938x: audio-codec {
>  		compatible = "qcom,wcd9385-codec";
>  
> @@ -1612,6 +1687,36 @@ wwan_sw_en: wwan-sw-en-state {
>  	};
>  };
>  
> +&pmk8550_vadc {

Idem, referenced existing nodes should also be sorted
alphabetically, so this should be the first node after
the existing &pmc8380_5_gpios reference.

Regards,

Hans



> +	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;
> +	};
> +};
> +
>  &usb_1_ss0_hsphy {
>  	vdd-supply = <&vreg_l3j_0p8>;
>  	vdda12-supply = <&vreg_l2j_1p2>;