Thermal: Add get trend, get instance API's to thermal_sys

This patch adds the following API's to thermal_sys.c, that
can be used by other Thermal drivers.
 * get_tz_trend: obtain the trend of the given thermal zone
 * get_thermal_instance: obtain the instance corresponding
   to the given tz, cdev and the trip point.
Signed-off-by: Durgadoss R <durgadoss.r@intel.com>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>

drivers/thermal/thermal_sys.c

@@ -82,6 +82,46 @@ static void release_idr(struct idr *idr, struct mutex *lock, int id)
 		mutex_unlock(lock);
 }
 
+int get_tz_trend(struct thermal_zone_device *tz, int trip)
+{
+	enum thermal_trend trend;
+
+	if (!tz->ops->get_trend || tz->ops->get_trend(tz, trip, &trend)) {
+		if (tz->temperature > tz->last_temperature)
+			trend = THERMAL_TREND_RAISING;
+		else if (tz->temperature < tz->last_temperature)
+			trend = THERMAL_TREND_DROPPING;
+		else
+			trend = THERMAL_TREND_STABLE;
+	}
+
+	return trend;
+}
+EXPORT_SYMBOL(get_tz_trend);
+
+struct thermal_instance *get_thermal_instance(struct thermal_zone_device *tz,
+			struct thermal_cooling_device *cdev, int trip)
+{
+	struct thermal_instance *pos = NULL;
+	struct thermal_instance *target_instance = NULL;
+
+	mutex_lock(&tz->lock);
+	mutex_lock(&cdev->lock);
+
+	list_for_each_entry(pos, &tz->thermal_instances, tz_node) {
+		if (pos->tz == tz && pos->trip == trip && pos->cdev == cdev) {
+			target_instance = pos;
+			break;
+		}
+	}
+
+	mutex_unlock(&cdev->lock);
+	mutex_unlock(&tz->lock);
+
+	return target_instance;
+}
+EXPORT_SYMBOL(get_thermal_instance);
+
 /* sys I/F for thermal zone */
 
 #define to_thermal_zone(_dev) \

include/linux/thermal.h

@@ -185,6 +185,10 @@ struct thermal_cooling_device *thermal_cooling_device_register(char *, void *,
 		const struct thermal_cooling_device_ops *);
 void thermal_cooling_device_unregister(struct thermal_cooling_device *);
 
+int get_tz_trend(struct thermal_zone_device *, int);
+struct thermal_instance *get_thermal_instance(struct thermal_zone_device *,
+		struct thermal_cooling_device *, int);
+
 #ifdef CONFIG_NET
 extern int thermal_generate_netlink_event(u32 orig, enum events event);
 #else