3 files changed, 59 insertions, 2 deletions

diff --git a/drivers/acpi/thermal.c b/drivers/acpi/thermal.c
index d7ef69d835f..bb95709a6be 100644
--- a/drivers/acpi/thermal.c
+++ b/drivers/acpi/thermal.c
@@ -706,6 +706,38 @@ static int thermal_get_crit_temp(struct thermal_zone_device *thermal,
                 return -EINVAL;
 }
 
+static int thermal_get_trend(struct thermal_zone_device *thermal,
+                                int trip, enum thermal_trend *trend)
+{
+        struct acpi_thermal *tz = thermal->devdata;
+        enum thermal_trip_type type;
+        int i;
+
+        if (thermal_get_trip_type(thermal, trip, &type))
+                return -EINVAL;
+
+        /* Only PASSIVE trip points need TREND */
+        if (type != THERMAL_TRIP_PASSIVE)
+                return -EINVAL;
+
+        /*
+         * tz->temperature has already been updated by generic thermal layer,
+         * before this callback being invoked
+         */
+        i = (tz->trips.passive.tc1 * (tz->temperature - tz->last_temperature))
+                + (tz->trips.passive.tc2
+                * (tz->temperature - tz->trips.passive.temperature));
+
+        if (i > 0)
+                *trend = THERMAL_TREND_RAISING;
+        else if (i < 0)
+                *trend = THERMAL_TREND_DROPPING;
+        else
+                *trend = THERMAL_TREND_STABLE;
+        return 0;
+}
+
+
 static int thermal_notify(struct thermal_zone_device *thermal, int trip,
                            enum thermal_trip_type trip_type)
 {
@@ -838,6 +870,7 @@ static const struct thermal_zone_device_ops acpi_thermal_zone_ops = {
         .get_trip_type = thermal_get_trip_type,
         .get_trip_temp = thermal_get_trip_temp,
         .get_crit_temp = thermal_get_crit_temp,
+        .get_trend = thermal_get_trend,
         .notify = thermal_notify,
 };
 
diff --git a/drivers/thermal/thermal_sys.c b/drivers/thermal/thermal_sys.c
index b04fe2c4b0d..146aa043f15 100644
--- a/drivers/thermal/thermal_sys.c
+++ b/drivers/thermal/thermal_sys.c
@@ -723,6 +723,20 @@ static void thermal_zone_device_passive(struct thermal_zone_device *tz,
         struct thermal_cooling_device *cdev;
         long state, max_state;
 
+        if (!tz->ops->get_trend ||
+            tz->ops->get_trend(tz, trip, (enum thermal_trend *)&trend)) {
+                /*
+                 * compare the current temperature and previous temperature
+                 * to get the thermal trend, if no special requirement
+                 */
+                if (tz->temperature > tz->last_temperature)
+                        trend = THERMAL_TREND_RAISING;
+                else if (tz->temperature < tz->last_temperature)
+                        trend = THERMAL_TREND_DROPPING;
+                else
+                        trend = THERMAL_TREND_STABLE;
+        }
+
         /*
          * Above Trip?
          * -----------
@@ -1091,6 +1105,9 @@ void thermal_zone_device_update(struct thermal_zone_device *tz)
                 goto leave;
         }
 
+        tz->last_temperature = tz->temperature;
+        tz->temperature = temp;
+
         for (count = 0; count < tz->trips; count++) {
                 tz->ops->get_trip_type(tz, count, &trip_type);
                 tz->ops->get_trip_temp(tz, count, &trip_temp);
@@ -1150,8 +1167,6 @@ void thermal_zone_device_update(struct thermal_zone_device *tz)
                 thermal_zone_device_passive(tz, temp, tz->forced_passive,
                                             THERMAL_TRIPS_NONE);
 
-        tz->last_temperature = temp;
-
 leave:
         if (tz->passive)
                 thermal_zone_device_set_polling(tz, tz->passive_delay);
diff --git a/include/linux/thermal.h b/include/linux/thermal.h
index 5946a3b90bb..6a1d43d2ec9 100644
--- a/include/linux/thermal.h
+++ b/include/linux/thermal.h
@@ -44,6 +44,12 @@ enum thermal_trip_type {
         THERMAL_TRIP_CRITICAL,
 };
 
+enum thermal_trend {
+        THERMAL_TREND_STABLE, /* temperature is stable */
+        THERMAL_TREND_RAISING, /* temperature is raising */
+        THERMAL_TREND_DROPPING, /* temperature is dropping */
+};
+
 struct thermal_zone_device_ops {
         int (*bind) (struct thermal_zone_device *,
                      struct thermal_cooling_device *);
@@ -65,6 +71,8 @@ struct thermal_zone_device_ops {
         int (*set_trip_hyst) (struct thermal_zone_device *, int,
                               unsigned long);
         int (*get_crit_temp) (struct thermal_zone_device *, unsigned long *);
+        int (*get_trend) (struct thermal_zone_device *, int,
+                          enum thermal_trend *);
         int (*notify) (struct thermal_zone_device *, int,
                        enum thermal_trip_type);
 };
@@ -111,6 +119,7 @@ struct thermal_zone_device {
         int tc2;
         int passive_delay;
         int polling_delay;
+        int temperature;
         int last_temperature;
         bool passive;
         unsigned int forced_passive;