thermal: core: Make thermal_zone_set_trips private

The function thermal_zone_set_trips() is used by the thermal core code
in order to update the next trip points, there are no other users.

Move the function definition in the thermal_core.h, remove the
EXPORT_SYMBOL_GPL and document the function.
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
Reviewed-by: Amit Kucheria <amit.kucheria@linaro.org>
Link: https://lore.kernel.org/r/20200331165449.30355-1-daniel.lezcano@linaro.org

drivers/thermal/thermal_core.h

@@ -69,6 +69,9 @@ void thermal_zone_device_unbind_exception(struct thermal_zone_device *,
 int thermal_zone_device_set_policy(struct thermal_zone_device *, char *);
 int thermal_build_list_of_policies(char *buf);
 
+/* Helpers */
+void thermal_zone_set_trips(struct thermal_zone_device *tz);
+
 /* sysfs I/F */
 int thermal_zone_create_device_groups(struct thermal_zone_device *, int);
 void thermal_zone_destroy_device_groups(struct thermal_zone_device *);

drivers/thermal/thermal_helpers.c

@@ -113,6 +113,18 @@ int thermal_zone_get_temp(struct thermal_zone_device *tz, int *temp)
 }
 EXPORT_SYMBOL_GPL(thermal_zone_get_temp);
 
+/**
+ * thermal_zone_set_trips - Computes the next trip points for the driver
+ * @tz: a pointer to a thermal zone device structure
+ *
+ * The function computes the next temperature boundaries by browsing
+ * the trip points. The result is the closer low and high trip points
+ * to the current temperature. These values are passed to the backend
+ * driver to let it set its own notification mechanism (usually an
+ * interrupt).
+ *
+ * It does not return a value
+ */
 void thermal_zone_set_trips(struct thermal_zone_device *tz)
 {
 	int low = -INT_MAX;
@@ -161,7 +173,6 @@ void thermal_zone_set_trips(struct thermal_zone_device *tz)
 exit:
 	mutex_unlock(&tz->lock);
 }
-EXPORT_SYMBOL_GPL(thermal_zone_set_trips);
 
 void thermal_cdev_update(struct thermal_cooling_device *cdev)
 {

include/linux/thermal.h

@@ -439,7 +439,6 @@ int thermal_zone_unbind_cooling_device(struct thermal_zone_device *, int,
 				       struct thermal_cooling_device *);
 void thermal_zone_device_update(struct thermal_zone_device *,
 				enum thermal_notify_event);
-void thermal_zone_set_trips(struct thermal_zone_device *);
 
 struct thermal_cooling_device *thermal_cooling_device_register(const char *,
 		void *, const struct thermal_cooling_device_ops *);
@@ -497,8 +496,6 @@ static inline int thermal_zone_unbind_cooling_device(
 static inline void thermal_zone_device_update(struct thermal_zone_device *tz,
 					      enum thermal_notify_event event)
 { }
-static inline void thermal_zone_set_trips(struct thermal_zone_device *tz)
-{ }
 static inline struct thermal_cooling_device *
 thermal_cooling_device_register(char *type, void *devdata,
 	const struct thermal_cooling_device_ops *ops)