[PATCHv2 3/3] thermal: improve hot trip handling

[Eduardo Valentin <edubezval@gmail.com>]

The idea is to add the choice to be notified only when temperature
crosses trip points. The trip points affected are the non-passive
trip points.

It will check last temperature and current temperature against
the trip point temperature and its hysteresis.
In case the check shows temperature has changed enought indicating
a trip point crossing, a uevent will be sent to userspace.

The uevent contains the thermal zone type, the current temperature,
the last temperature and the trip point in which the current temperature
now resides.

The behavior of ops->notify() callback remains the same.

Cc: Zhang Rui <rui.zhang@intel.com>
Cc: linux-pm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
---
V1->V2: none
---
 drivers/thermal/thermal_core.c | 52 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 52 insertions(+)

diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
index a229c84..e0f1f4e 100644
--- a/drivers/thermal/thermal_core.c
+++ b/drivers/thermal/thermal_core.c
@@ -423,6 +423,56 @@ static void handle_non_critical_trips(struct thermal_zone_device *tz,
 		       def_governor->throttle(tz, trip);
 }
 
+static void thermal_tripped_notify(struct thermal_zone_device *tz,
+				   int trip, enum thermal_trip_type trip_type,
+				   int trip_temp)
+{
+	char tuv_name[THERMAL_NAME_LENGTH + 15], tuv_temp[25],
+		tuv_ltemp[25], tuv_trip[25], tuv_type[25];
+	char *msg[6] = { tuv_name, tuv_temp, tuv_ltemp, tuv_trip, tuv_type,
+			NULL };
+	int upper_trip_hyst, upper_trip_temp, trip_hyst = 0;
+	int ret = 0;
+
+	snprintf(tuv_name, sizeof(tuv_name), "THERMAL_ZONE=%s", tz->type);
+	snprintf(tuv_temp, sizeof(tuv_temp), "TEMP=%d", tz->temperature);
+	snprintf(tuv_ltemp, sizeof(tuv_ltemp), "LAST_TEMP=%d",
+		 tz->last_temperature);
+	snprintf(tuv_trip, sizeof(tuv_trip), "TRIP=%d", trip);
+	snprintf(tuv_type, sizeof(tuv_type), "TRIP_TYPE=%d", trip_type);
+
+	mutex_lock(&tz->lock);
+
+	/* crossing up */
+	if (tz->last_temperature < trip_temp && trip_temp < tz->temperature)
+		kobject_uevent_env(&tz->device.kobj, KOBJ_CHANGE, msg);
+
+	if (tz->ops->get_trip_hyst)
+		tz->ops->get_trip_hyst(tz, trip, &trip_hyst);
+
+	/* crossing down, check for hyst */
+	trip_temp -= trip_hyst;
+	if (tz->last_temperature > trip_temp && trip_temp > tz->temperature) {
+		snprintf(tuv_trip, sizeof(tuv_trip), "TRIP=%d", trip - 1);
+		kobject_uevent_env(&tz->device.kobj, KOBJ_CHANGE, msg);
+	}
+
+	ret = tz->ops->get_trip_temp(tz, trip + 1, &upper_trip_temp);
+	if (ret)
+		goto unlock;
+
+	if (tz->ops->get_trip_hyst)
+		tz->ops->get_trip_hyst(tz, trip + 1, &upper_trip_hyst);
+
+	upper_trip_temp -= upper_trip_hyst;
+	if (tz->last_temperature > upper_trip_temp &&
+	    upper_trip_temp > tz->temperature)
+		kobject_uevent_env(&tz->device.kobj, KOBJ_CHANGE, msg);
+
+unlock:
+	mutex_unlock(&tz->lock);
+}
+
 static void handle_critical_trips(struct thermal_zone_device *tz,
 				int trip, enum thermal_trip_type trip_type)
 {
@@ -430,6 +480,8 @@ static void handle_critical_trips(struct thermal_zone_device *tz,
 
 	tz->ops->get_trip_temp(tz, trip, &trip_temp);
 
+	thermal_tripped_notify(tz, trip, trip_type, trip_temp);
+
 	/* If we have not crossed the trip_temp, we do not care. */
 	if (trip_temp <= 0 || tz->temperature < trip_temp)
 		return;
-- 
2.5.0