thermal: of: Extend of-thermal.c to provide check if trip point is valid

This patch extends the of-thermal.c to provide check if trip point is
valid.

Signed-off-by: Lukasz Majewski <l.majewski@samsung.com>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>

drivers/thermal/of-thermal.c

@@ -133,6 +133,27 @@ int of_thermal_get_ntrips(struct thermal_zone_device *tz)
 }
 EXPORT_SYMBOL_GPL(of_thermal_get_ntrips);
 
+/**
+ * of_thermal_is_trip_valid - function to check if trip point is valid
+ *
+ * @tz:	pointer to a thermal zone
+ * @trip:	trip point to evaluate
+ *
+ * This function is responsible for checking if passed trip point is valid
+ *
+ * Return: true if trip point is valid, false otherwise
+ */
+bool of_thermal_is_trip_valid(struct thermal_zone_device *tz, int trip)
+{
+	struct __thermal_zone *data = tz->devdata;
+
+	if (!data || trip >= data->ntrips || trip < 0)
+		return false;
+
+	return true;
+}
+EXPORT_SYMBOL_GPL(of_thermal_is_trip_valid);
+
 static int of_thermal_get_trend(struct thermal_zone_device *tz, int trip,
 				enum thermal_trend *trend)
 {