thermal/core: Compute low and high boundaries in thermal_zone_device_update()

In order to set the scene for the thresholds support which have to
manipulate the low and high temperature boundaries for the interrupt
support, we must pass the low and high values to the incoming
thresholds routine.

The variables are set from the thermal_zone_set_trips() where the
function loops the thermal trips to figure out the next and the
previous temperatures to set the interrupt to be triggered when they
are crossed.

These variables will be needed by the function in charge of handling
the thresholds in the incoming changes but they are local to the
aforementioned function thermal_zone_set_trips().

Move the low and high boundaries computation out of the function in
thermal_zone_device_update() so they are accessible from there.

The positive side effect is they are computed in the same loop as
handle_thermal_trip(), so we remove one loop.

Co-developed-by: Rafael J. Wysocki <[e-mail]>
Signed-off-by: Daniel Lezcano <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Rafael J. Wysocki <[e-mail]>

drivers/thermal/thermal_core.c

···
 	struct thermal_trip_desc *td;
 	LIST_HEAD(way_down_list);
 	LIST_HEAD(way_up_list);
+	int low = -INT_MAX, high = INT_MAX;
 	int temp, ret;
 
 	if (tz->suspended)
···
 
 	tz->notify_event = event;
 
-	for_each_trip_desc(tz, td)
+	for_each_trip_desc(tz, td) {
 		handle_thermal_trip(tz, td, &way_up_list, &way_down_list);
 
-	thermal_zone_set_trips(tz);
+		if (td->threshold <= tz->temperature && td->threshold > low)
+			low = td->threshold;
+
+		if (td->threshold >= tz->temperature && td->threshold < high)
+			high = td->threshold;
+	}
+
+	thermal_zone_set_trips(tz, low, high);
 
 	list_sort(NULL, &way_up_list, thermal_trip_notify_cmp);
 	list_for_each_entry(td, &way_up_list, notify_list_node)

drivers/thermal/thermal_core.h

···
 
 const char *thermal_trip_type_name(enum thermal_trip_type trip_type);
 
-void thermal_zone_set_trips(struct thermal_zone_device *tz);
+void thermal_zone_set_trips(struct thermal_zone_device *tz, int low, int high);
 int thermal_zone_trip_id(const struct thermal_zone_device *tz,
 			 const struct thermal_trip *trip);
 int __thermal_zone_get_temp(struct thermal_zone_device *tz, int *temp);

drivers/thermal/thermal_trip.c

···
 }
 EXPORT_SYMBOL_GPL(thermal_zone_for_each_trip);
 
-/**
- * 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).
- *
- * This function must be called with tz->lock held. Both tz and tz->ops
- * must be valid pointers.
- *
- * It does not return a value
- */
-void thermal_zone_set_trips(struct thermal_zone_device *tz)
+void thermal_zone_set_trips(struct thermal_zone_device *tz, int low, int high)
 {
-	const struct thermal_trip_desc *td;
-	int low = -INT_MAX, high = INT_MAX;
 	int ret;
 
 	lockdep_assert_held(&tz->lock);
 
 	if (!tz->ops.set_trips)
 		return;
-
-	for_each_trip_desc(tz, td) {
-		if (td->threshold <= tz->temperature && td->threshold > low)
-			low = td->threshold;
-
-		if (td->threshold >= tz->temperature && td->threshold < high)
-			high = td->threshold;
-	}
 
 	/* No need to change trip points */
 	if (tz->prev_low_trip == low && tz->prev_high_trip == high)