thermal: helpers: Introduce thermal_trip_is_bound_to_cdev()

Introduce a new helper function thermal_trip_is_bound_to_cdev() for
checking whether or not a given trip point has been bound to a given
cooling device.

The primary user of it will be the Tegra thermal driver.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://patch.msgid.link/13545762.uLZWGnKmhe@rjwysocki.net

drivers/thermal/thermal_helpers.c

@@ -39,30 +39,53 @@ int get_tz_trend(struct thermal_zone_device *tz, const struct thermal_trip *trip
 	return trend;
 }
 
+static struct thermal_instance *get_instance(struct thermal_zone_device *tz,
+					     struct thermal_cooling_device *cdev,
+					     const struct thermal_trip *trip)
+{
+	struct thermal_instance *ti;
+
+	list_for_each_entry(ti, &tz->thermal_instances, tz_node) {
+		if (ti->trip == trip && ti->cdev == cdev)
+			return ti;
+	}
+
+	return NULL;
+}
+
+bool thermal_trip_is_bound_to_cdev(struct thermal_zone_device *tz,
+				   const struct thermal_trip *trip,
+				   struct thermal_cooling_device *cdev)
+{
+	bool ret;
+
+	mutex_lock(&tz->lock);
+	mutex_lock(&cdev->lock);
+
+	ret = !!get_instance(tz, cdev, trip);
+
+	mutex_unlock(&cdev->lock);
+	mutex_unlock(&tz->lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(thermal_trip_is_bound_to_cdev);
+
 struct thermal_instance *
 get_thermal_instance(struct thermal_zone_device *tz,
 		     struct thermal_cooling_device *cdev, int trip_index)
 {
-	struct thermal_instance *pos = NULL;
-	struct thermal_instance *target_instance = NULL;
-	const struct thermal_trip *trip;
+	struct thermal_instance *ti;
 
 	mutex_lock(&tz->lock);
 	mutex_lock(&cdev->lock);
 
-	trip = &tz->trips[trip_index].trip;
-
-	list_for_each_entry(pos, &tz->thermal_instances, tz_node) {
-		if (pos->tz == tz && pos->trip == trip && pos->cdev == cdev) {
-			target_instance = pos;
-			break;
-		}
-	}
+	ti = get_instance(tz, cdev, &tz->trips[trip_index].trip);
 
 	mutex_unlock(&cdev->lock);
 	mutex_unlock(&tz->lock);
 
-	return target_instance;
+	return ti;
 }
 EXPORT_SYMBOL(get_thermal_instance);
 

include/linux/thermal.h

@@ -270,6 +270,9 @@ struct thermal_zone_device *thermal_zone_get_zone_by_name(const char *name);
 int thermal_zone_get_temp(struct thermal_zone_device *tz, int *temp);
 int thermal_zone_get_slope(struct thermal_zone_device *tz);
 int thermal_zone_get_offset(struct thermal_zone_device *tz);
+bool thermal_trip_is_bound_to_cdev(struct thermal_zone_device *tz,
+				   const struct thermal_trip *trip,
+				   struct thermal_cooling_device *cdev);
 
 int thermal_zone_device_enable(struct thermal_zone_device *tz);
 int thermal_zone_device_disable(struct thermal_zone_device *tz);