arm64: dts: qcom: pm8998: Add pm8998 thermal zone

The thermal zone uses spmi-temp-alarm as sensor, the trip points
correspond to the PMIC thermal stages 1 and 2. The critical trip
point at 125°C disables the partial PMIC shutdown at stage 2.

Without an IIO input the sensor only reports a limited number of
temperatures:

- 37°C for temperatures below 105°C
- 107°C for temperatures >= 105°C and < 125°C
- 127°C for temperatures >= 125°C

(the numbers correspond to a stage 1 threshold of 105°C)

Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Andy Gross <andy.gross@linaro.org>

arch/arm64/boot/dts/qcom/pm8998.dtsi

@@ -5,7 +5,31 @@
 #include <dt-bindings/input/linux-event-codes.h>
 #include <dt-bindings/interrupt-controller/irq.h>
 #include <dt-bindings/spmi/spmi.h>
+#include <dt-bindings/thermal/thermal.h>
 
+/ {
+	thermal-zones {
+		pm8998 {
+			polling-delay-passive = <250>;
+			polling-delay = <1000>;
+
+			thermal-sensors = <&pm8998_temp>;
+
+			trips {
+				pm8998_alert0: pm8998-alert0 {
+					temperature = <105000>;
+					hysteresis = <2000>;
+					type = "passive";
+				};
+				pm8998_crit: pm8998-crit {
+					temperature = <125000>;
+					hysteresis = <2000>;
+					type = "critical";
+				};
+			};
+		};
+	};
+};
 
 &spmi_bus {
 	pm8998_lsid0: pmic@0 {