thermal/core: Add a generic thermal_zone_set_trip() function

The thermal zone ops defines a set_trip callback where we can invoke
the backend driver to set an interrupt for the next trip point
temperature being crossed the way up or down, or setting the low level
with the hysteresis.

The ops is only called from the thermal sysfs code where the userspace
has the ability to modify a trip point characteristic.

With the effort of encapsulating the thermal framework core code,
let's create a thermal_zone_set_trip() which is the writable side of
the thermal_zone_get_trip() and put there all the ops encapsulation.
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lore.kernel.org/r/20221003092602.1323944-4-daniel.lezcano@linaro.org

drivers/thermal/thermal_core.c

@@ -1228,6 +1228,45 @@ int thermal_zone_get_trip(struct thermal_zone_device *tz, int trip_id,
 }
 EXPORT_SYMBOL_GPL(thermal_zone_get_trip);
 
+int thermal_zone_set_trip(struct thermal_zone_device *tz, int trip_id,
+			  const struct thermal_trip *trip)
+{
+	struct thermal_trip t;
+	int ret;
+
+	if (!tz->ops->set_trip_temp && !tz->ops->set_trip_hyst && !tz->trips)
+		return -EINVAL;
+
+	ret = __thermal_zone_get_trip(tz, trip_id, &t);
+	if (ret)
+		return ret;
+
+	if (t.type != trip->type)
+		return -EINVAL;
+
+	if (t.temperature != trip->temperature && tz->ops->set_trip_temp) {
+		ret = tz->ops->set_trip_temp(tz, trip_id, trip->temperature);
+		if (ret)
+			return ret;
+	}
+
+	if (t.hysteresis != trip->hysteresis && tz->ops->set_trip_hyst) {
+		ret = tz->ops->set_trip_hyst(tz, trip_id, trip->hysteresis);
+		if (ret)
+			return ret;
+	}
+
+	if (tz->trips && (t.temperature != trip->temperature || t.hysteresis != trip->hysteresis))
+		tz->trips[trip_id] = *trip;
+
+	thermal_notify_tz_trip_change(tz->id, trip_id, trip->type,
+				      trip->temperature, trip->hysteresis);
+
+	__thermal_zone_device_update(tz, THERMAL_TRIP_CHANGED);
+	
+	return 0;
+}
+
 /**
  * thermal_zone_device_register_with_trips() - register a new thermal zone device
  * @type:	the thermal zone device type

drivers/thermal/thermal_sysfs.c

@@ -123,15 +123,9 @@ trip_point_temp_store(struct device *dev, struct device_attribute *attr,
 	struct thermal_trip trip;
 	int trip_id, ret;
 
-	if (!tz->ops->set_trip_temp && !tz->trips)
-		return -EPERM;
-
 	if (sscanf(attr->attr.name, "trip_point_%d_temp", &trip_id) != 1)
 		return -EINVAL;
 
-	if (kstrtoint(buf, 10, &trip.temperature))
-		return -EINVAL;
-
 	mutex_lock(&tz->lock);
 
 	if (!device_is_registered(dev)) {
@@ -139,31 +133,19 @@ trip_point_temp_store(struct device *dev, struct device_attribute *attr,
 		goto unlock;
 	}
 
-	if (tz->ops->set_trip_temp) {
-		ret = tz->ops->set_trip_temp(tz, trip_id, trip.temperature);
+	ret = __thermal_zone_get_trip(tz, trip_id, &trip);
 	if (ret)
 		goto unlock;
-	}
-
-	if (tz->trips)
-		tz->trips[trip_id].temperature = trip.temperature;
 
-	ret = __thermal_zone_get_trip(tz, trip_id, &trip);
+	ret = kstrtoint(buf, 10, &trip.temperature);
 	if (ret)
 		goto unlock;
 
-	thermal_notify_tz_trip_change(tz->id, trip_id, trip.type,
-				      trip.temperature, trip.hysteresis);
-
-	__thermal_zone_device_update(tz, THERMAL_EVENT_UNSPECIFIED);
-
+	ret = thermal_zone_set_trip(tz, trip_id, &trip);
 unlock:
 	mutex_unlock(&tz->lock);
 	
-	if (ret)
-		return ret;
-
-	return count;
+	return ret ? ret : count;
 }
 
 static ssize_t
@@ -197,16 +179,13 @@ trip_point_hyst_store(struct device *dev, struct device_attribute *attr,
 		      const char *buf, size_t count)
 {
 	struct thermal_zone_device *tz = to_thermal_zone(dev);
-	int trip, ret;
-	int temperature;
-
-	if (!tz->ops->set_trip_hyst)
-		return -EPERM;
+	struct thermal_trip trip;
+	int trip_id, ret;
 
-	if (sscanf(attr->attr.name, "trip_point_%d_hyst", &trip) != 1)
+	if (sscanf(attr->attr.name, "trip_point_%d_hyst", &trip_id) != 1)
 		return -EINVAL;
 
-	if (kstrtoint(buf, 10, &temperature))
+	if (kstrtoint(buf, 10, &trip.hysteresis))
 		return -EINVAL;
 
 	mutex_lock(&tz->lock);
@@ -216,16 +195,11 @@ trip_point_hyst_store(struct device *dev, struct device_attribute *attr,
 		goto unlock;
 	}
 
-	/*
-	 * We are not doing any check on the 'temperature' value
-	 * here. The driver implementing 'set_trip_hyst' has to
-	 * take care of this.
-	 */
-	ret = tz->ops->set_trip_hyst(tz, trip, temperature);
-
-	if (!ret)
-		__thermal_zone_set_trips(tz);
+	ret = __thermal_zone_get_trip(tz, trip_id, &trip);
+	if (ret)
+		goto unlock;
 	
+	ret = thermal_zone_set_trip(tz, trip_id, &trip);
 unlock:
 	mutex_unlock(&tz->lock);
 

include/linux/thermal.h

@@ -337,6 +337,9 @@ static inline void devm_thermal_of_zone_unregister(struct device *dev,
 int thermal_zone_get_trip(struct thermal_zone_device *tz, int trip_id,
 			  struct thermal_trip *trip);
 
+int thermal_zone_set_trip(struct thermal_zone_device *tz, int trip_id,
+			  const struct thermal_trip *trip);
+
 int thermal_zone_get_num_trips(struct thermal_zone_device *tz);
 
 int thermal_zone_get_crit_temp(struct thermal_zone_device *tz, int *temp);