thermal: sysfs: Rework the reading of trip point attributes

Rework the _show() callback functions for the trip point temperature,
hysteresis and type attributes to avoid copying the values of struct
thermal_trip fields that they do not use and make them carry out the
same validation checks as the corresponding _store() callback functions.

No intentional functional impact.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Daniel Lezcano <daniel.lezcano@linaro.org>

drivers/thermal/thermal_sysfs.c

@@ -83,25 +83,24 @@ trip_point_type_show(struct device *dev, struct device_attribute *attr,
 		     char *buf)
 {
 	struct thermal_zone_device *tz = to_thermal_zone(dev);
-	struct thermal_trip trip;
-	int trip_id, result;
+	enum thermal_trip_type type;
+	int trip_id;
 
 	if (sscanf(attr->attr.name, "trip_point_%d_type", &trip_id) != 1)
 		return -EINVAL;
 
 	mutex_lock(&tz->lock);
 
-	if (device_is_registered(dev))
-		result = __thermal_zone_get_trip(tz, trip_id, &trip);
-	else
-		result = -ENODEV;
-
+	if (!device_is_registered(dev)) {
 		mutex_unlock(&tz->lock);
+		return -ENODEV;
+	}
 
-	if (result)
-		return result;
+	type = tz->trips[trip_id].type;
 
-	switch (trip.type) {
+	mutex_unlock(&tz->lock);
+
+	switch (type) {
 	case THERMAL_TRIP_CRITICAL:
 		return sprintf(buf, "critical\n");
 	case THERMAL_TRIP_HOT:
@@ -163,25 +162,23 @@ trip_point_temp_show(struct device *dev, struct device_attribute *attr,
 		     char *buf)
 {
 	struct thermal_zone_device *tz = to_thermal_zone(dev);
-	struct thermal_trip trip;
-	int trip_id, ret;
+	int trip_id, temp;
 
 	if (sscanf(attr->attr.name, "trip_point_%d_temp", &trip_id) != 1)
 		return -EINVAL;
 
 	mutex_lock(&tz->lock);
 
-	if (device_is_registered(dev))
-		ret = __thermal_zone_get_trip(tz, trip_id, &trip);
-	else
-		ret = -ENODEV;
-
+	if (!device_is_registered(dev)) {
 		mutex_unlock(&tz->lock);
+		return -ENODEV;
+	}
 
-	if (ret)
-		return ret;
+	temp = tz->trips[trip_id].temperature;
 
-	return sprintf(buf, "%d\n", trip.temperature);
+	mutex_unlock(&tz->lock);
+
+	return sprintf(buf, "%d\n", temp);
 }
 
 static ssize_t
@@ -232,22 +229,23 @@ trip_point_hyst_show(struct device *dev, struct device_attribute *attr,
 		     char *buf)
 {
 	struct thermal_zone_device *tz = to_thermal_zone(dev);
-	struct thermal_trip trip;
-	int trip_id, ret;
+	int trip_id, hyst;
 
 	if (sscanf(attr->attr.name, "trip_point_%d_hyst", &trip_id) != 1)
 		return -EINVAL;
 
 	mutex_lock(&tz->lock);
 
-	if (device_is_registered(dev))
-		ret = __thermal_zone_get_trip(tz, trip_id, &trip);
-	else
-		ret = -ENODEV;
+	if (!device_is_registered(dev)) {
+		mutex_unlock(&tz->lock);
+		return -ENODEV;
+	}
+
+	hyst = tz->trips[trip_id].hysteresis;
 
 	mutex_unlock(&tz->lock);
 
-	return ret ? ret : sprintf(buf, "%d\n", trip.hysteresis);
+	return sprintf(buf, "%d\n", hyst);
 }
 
 static ssize_t