thermal: tegra: add get_trend ops

Add support for get_trend ops that allows soctherm
sensors to be used with the step-wise governor.
Signed-off-by: Wei Ni <wni@nvidia.com>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>

drivers/thermal/tegra/soctherm.c

@@ -488,9 +488,41 @@ static int tegra_thermctl_set_trip_temp(void *data, int trip, int temp)
 	return 0;
 }
 
+static int tegra_thermctl_get_trend(void *data, int trip,
+				    enum thermal_trend *trend)
+{
+	struct tegra_thermctl_zone *zone = data;
+	struct thermal_zone_device *tz = zone->tz;
+	int trip_temp, temp, last_temp, ret;
+
+	if (!tz)
+		return -EINVAL;
+
+	ret = tz->ops->get_trip_temp(zone->tz, trip, &trip_temp);
+	if (ret)
+		return ret;
+
+	temp = READ_ONCE(tz->temperature);
+	last_temp = READ_ONCE(tz->last_temperature);
+
+	if (temp > trip_temp) {
+		if (temp >= last_temp)
+			*trend = THERMAL_TREND_RAISING;
+		else
+			*trend = THERMAL_TREND_STABLE;
+	} else if (temp < trip_temp) {
+		*trend = THERMAL_TREND_DROPPING;
+	} else {
+		*trend = THERMAL_TREND_STABLE;
+	}
+
+	return 0;
+}
+
 static const struct thermal_zone_of_device_ops tegra_of_thermal_ops = {
 	.get_temp = tegra_thermctl_get_temp,
 	.set_trip_temp = tegra_thermctl_set_trip_temp,
+	.get_trend = tegra_thermctl_get_trend,
 };
 
 static int get_hot_temp(struct thermal_zone_device *tz, int *trip, int *temp)