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

[Daniel Lezcano]

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@xxxxxxxxxxxxxxxx>
---
 .../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
@@ -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;
+	};
+};
-- 
2.53.0