thermal/sysfs: Always expose hysteresis attributes

Instead of avoiding to expose the hysteresis attributes of a thermal
zone when its get_trip_hyst() operation is not defined, which is
confusing, expose them always and use the default
thermal_zone_get_trip() function returning 0 hysteresis when that
operation is not present.

The hysteresis of 0 is perfectly valid, so this change should not
introduce any backwards compatibility issues.
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/20221003092602.1323944-3-daniel.lezcano@linaro.org

drivers/thermal/thermal_sysfs.c

@@ -477,23 +477,20 @@ static int create_trip_attrs(struct thermal_zone_device *tz, int mask)
 		return -ENOMEM;
 	}
 
-	if (tz->ops->get_trip_hyst) {
-		tz->trip_hyst_attrs = kcalloc(tz->num_trips,
-					      sizeof(*tz->trip_hyst_attrs),
-					      GFP_KERNEL);
-		if (!tz->trip_hyst_attrs) {
-			kfree(tz->trip_type_attrs);
-			kfree(tz->trip_temp_attrs);
-			return -ENOMEM;
-		}
+	tz->trip_hyst_attrs = kcalloc(tz->num_trips,
+				      sizeof(*tz->trip_hyst_attrs),
+				      GFP_KERNEL);
+	if (!tz->trip_hyst_attrs) {
+		kfree(tz->trip_type_attrs);
+		kfree(tz->trip_temp_attrs);
+		return -ENOMEM;
 	}
 
 	attrs = kcalloc(tz->num_trips * 3 + 1, sizeof(*attrs), GFP_KERNEL);
 	if (!attrs) {
 		kfree(tz->trip_type_attrs);
 		kfree(tz->trip_temp_attrs);
-		if (tz->ops->get_trip_hyst)
-			kfree(tz->trip_hyst_attrs);
+		kfree(tz->trip_hyst_attrs);
 		return -ENOMEM;
 	}
 
@@ -526,9 +523,6 @@ static int create_trip_attrs(struct thermal_zone_device *tz, int mask)
 		}
 		attrs[indx + tz->num_trips] = &tz->trip_temp_attrs[indx].attr.attr;
 
-		/* create Optional trip hyst attribute */
-		if (!tz->ops->get_trip_hyst)
-			continue;
 		snprintf(tz->trip_hyst_attrs[indx].name, THERMAL_NAME_LENGTH,
 			 "trip_point_%d_hyst", indx);
 
@@ -565,8 +559,7 @@ static void destroy_trip_attrs(struct thermal_zone_device *tz)
 
 	kfree(tz->trip_type_attrs);
 	kfree(tz->trip_temp_attrs);
-	if (tz->ops->get_trip_hyst)
-		kfree(tz->trip_hyst_attrs);
+	kfree(tz->trip_hyst_attrs);
 	kfree(tz->trips_attribute_group.attrs);
 }