Thermal: Introduce thermal_zone_trip_update()

This function is used to update the cooling state of
all the cooling devices that are bound to an active trip point.

This will be used for passive cooling as well, in the future patches.
as both active and passive cooling can share the same algorithm,
which is

1. if the temperature is higher than a trip point,
   a. if the trend is THERMAL_TREND_RAISING, use higher cooling
      state for this trip point
   b. if the trend is THERMAL_TREND_DROPPING, use lower cooling
      state for this trip point

2. if the temperature is lower than a trip point, use lower
   cooling state for this trip point.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Reviewed-by: Rafael J. Wysocki <rjw@sisk.pl>
Reviewed-by: Eduardo Valentin <eduardo.valentin@ti.com>

1 files changed, 5 insertions, 3 deletions

diff --git a/drivers/acpi/thermal.c b/drivers/acpi/thermal.c
index 07cb2172bd09..bd66bd28a43f 100644
--- a/drivers/acpi/thermal.c
+++ b/drivers/acpi/thermal.c
@@ -716,9 +716,11 @@ static int thermal_get_trend(struct thermal_zone_device *thermal,
         if (thermal_get_trip_type(thermal, trip, &type))
                 return -EINVAL;
 
-        /* Only PASSIVE trip points need TREND */
-        if (type != THERMAL_TRIP_PASSIVE)
-                return -EINVAL;
+        if (type == THERMAL_TRIP_ACTIVE) {
+                /* aggressive active cooling */
+                *trend = THERMAL_TREND_RAISING;
+                return 0;
+        }
 
         /*
          * tz->temperature has already been updated by generic thermal layer,