Thermal: thermal zone governor fix

This patch does a cleanup about the thermal zone govenor,
setting and make the following rule.
1. For thermal zone devices that are registered w/o tz->tzp,
   they can use the default thermal governor only.
2. For thermal zone devices w/ governor name specified in
   tz->tzp->governor_name, we will use the default govenor
   if the governor specified is not available at the moment,
   and update tz->governor when the matched governor is registered.

This also fixes a problem that OF registered thermal zones
are running with no governor.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Acked-by: Javi Merino <javi.merino@arm.com>

diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
index 02f57af04e3f51d3b4968f011882a6d289664dd0..71b0ec0c370d73aad18d685118c197735c5b2833 100644 (file)
--- a/drivers/thermal/thermal_core.c
+++ b/drivers/thermal/thermal_core.c
@@ -56,10 +56,15 @@ static LIST_HEAD(thermal_governor_list);
 static DEFINE_MUTEX(thermal_list_lock);
 static DEFINE_MUTEX(thermal_governor_lock);
 
+static struct thermal_governor *def_governor;
+
 static struct thermal_governor *__find_governor(const char *name)
 {
        struct thermal_governor *pos;
 
+       if (!name || !name[0])
+               return def_governor;
+
        list_for_each_entry(pos, &thermal_governor_list, governor_list)
                if (!strnicmp(name, pos->name, THERMAL_NAME_LENGTH))
                        return pos;
@@ -82,17 +87,23 @@ int thermal_register_governor(struct thermal_governor *governor)
        if (__find_governor(governor->name) == NULL) {
                err = 0;
                list_add(&governor->governor_list, &thermal_governor_list);
+               if (!def_governor && !strncmp(governor->name,
+                       DEFAULT_THERMAL_GOVERNOR, THERMAL_NAME_LENGTH))
+                       def_governor = governor;
        }
 
        mutex_lock(&thermal_list_lock);
 
        list_for_each_entry(pos, &thermal_tz_list, node) {
+               /*
+                * only thermal zones with specified tz->tzp->governor_name
+                * may run with tz->govenor unset
+                */
                if (pos->governor)
                        continue;
-               if (pos->tzp)
-                       name = pos->tzp->governor_name;
-               else
-                       name = DEFAULT_THERMAL_GOVERNOR;
+
+               name = pos->tzp->governor_name;
+
                if (!strnicmp(name, governor->name, THERMAL_NAME_LENGTH))
                        pos->governor = governor;
        }
@@ -342,8 +353,8 @@ static void monitor_thermal_zone(struct thermal_zone_device *tz)
 static void handle_non_critical_trips(struct thermal_zone_device *tz,
                        int trip, enum thermal_trip_type trip_type)
 {
-       if (tz->governor)
-               tz->governor->throttle(tz, trip);
+       tz->governor ? tz->governor->throttle(tz, trip) :
+                      def_governor->throttle(tz, trip);
 }
 
 static void handle_critical_trips(struct thermal_zone_device *tz,
@@ -1533,7 +1544,7 @@ struct thermal_zone_device *thermal_zone_device_register(const char *type,
        if (tz->tzp)
                tz->governor = __find_governor(tz->tzp->governor_name);
        else
-               tz->governor = __find_governor(DEFAULT_THERMAL_GOVERNOR);
+               tz->governor = def_governor;
 
        mutex_unlock(&thermal_governor_lock);