of: Add bindings of thermtrip for Tegra soctherm

Add optional property "nvidia,thermtrips".
If present, these trips will be used as HW shutdown trips,
and critical trips will be used as SW shutdown trips.
Signed-off-by: Wei Ni <wni@nvidia.com>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>

Documentation/devicetree/bindings/thermal/nvidia,tegra124-soctherm.txt

@@ -55,10 +55,21 @@ Required properties :
       - #cooling-cells: Should be 1. This cooling device only support on/off state.
         See ./thermal.txt for a description of this property.
 
+Optional properties:
+- nvidia,thermtrips : When present, this property specifies the temperature at
+  which the soctherm hardware will assert the thermal trigger signal to the
+  Power Management IC, which can be configured to reset or shutdown the device.
+  It is an array of pairs where each pair represents a tsensor id followed by a
+  temperature in milli Celcius. In the absence of this property the critical
+  trip point will be used for thermtrip temperature.
+
 Note:
-- the "critical" type trip points will be set to SOC_THERM hardware as the
-shut down temperature. Once the temperature of this thermal zone is higher
-than it, the system will be shutdown or reset by hardware.
+- the "critical" type trip points will be used to set the temperature at which
+the SOC_THERM hardware will assert a thermal trigger if the "nvidia,thermtrips"
+property is missing. When the thermtrips property is present, the breach of a
+critical trip point is reported back to the thermal framework to implement
+software shutdown.
+
 - the "hot" type trip points will be set to SOC_THERM hardware as the throttle
 temperature. Once the the temperature of this thermal zone is higher
 than it, it will trigger the HW throttle event.
@@ -79,6 +90,9 @@ Example :
 
 		#thermal-sensor-cells = <1>;
 
+		nvidia,thermtrips = <TEGRA124_SOCTHERM_SENSOR_CPU 102500
+				     TEGRA124_SOCTHERM_SENSOR_GPU 103000>;
+
 		throttle-cfgs {
 			/*
 			 * When the "heavy" cooling device triggered,