Merge tag 'platform-drivers-x86-v4.7-2' of git://git.infradead.org/users/dvhart/linux...

[deliverable/linux.git] / drivers / thermal / gov_bang_bang.c

diff --git a/drivers/thermal/gov_bang_bang.c b/drivers/thermal/gov_bang_bang.c
index 70836c5b89bc411d3a1b91ebea91c3b8f92b4dba..fc52016d4e85be590e15f4e1976b8378d2c456d2 100644 (file)
--- a/drivers/thermal/gov_bang_bang.c
+++ b/drivers/thermal/gov_bang_bang.c
@@ -29,7 +29,13 @@ static void thermal_zone_trip_update(struct thermal_zone_device *tz, int trip)
        struct thermal_instance *instance;
 
        tz->ops->get_trip_temp(tz, trip, &trip_temp);
-       tz->ops->get_trip_hyst(tz, trip, &trip_hyst);
+
+       if (!tz->ops->get_trip_hyst) {
+               pr_warn_once("Undefined get_trip_hyst for thermal zone %s - "
+                               "running with default hysteresis zero\n", tz->type);
+               trip_hyst = 0;
+       } else
+               tz->ops->get_trip_hyst(tz, trip, &trip_hyst);
 
        dev_dbg(&tz->device, "Trip%d[temp=%d]:temp=%d:hyst=%d\n",
                                trip, trip_temp, tz->temperature,