[PATCH V4 1/3] Thermal: initialize thermal zone device correctly

[Zhang Rui <rui.zhang@intel.com>]

After thermal zone device registered, as we have not read any
temperature before, thus tz->temperature should not be 0, which actually
means 0C, and thermal trend is not available.
In this case, we need specially handling for the first
thermal_zone_device_update().

Both thermal core framework and step_wise governor is enhanced to handle this.

CC: <stable@vger.kernel.org> #3.18+
Tested-by: Manuel Krause <manuelkrause@netscape.net>
Tested-by: szegad <szegadlo@poczta.onet.pl>
Tested-by: prash <prash.n.rao@gmail.com>
Tested-by: amish <ammdispose-arch@yahoo.com>
Tested-by: Matthias <morpheusxyz123@yahoo.de>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
---
 drivers/thermal/step_wise.c    | 15 +++++++++++++--
 drivers/thermal/thermal_core.c | 19 +++++++++++++++++--
 drivers/thermal/thermal_core.h |  1 +
 include/linux/thermal.h        |  3 +++
 4 files changed, 34 insertions(+), 4 deletions(-)

diff --git a/drivers/thermal/step_wise.c b/drivers/thermal/step_wise.c
index 5a0f12d..c2bb37c 100644
--- a/drivers/thermal/step_wise.c
+++ b/drivers/thermal/step_wise.c
@@ -63,6 +63,16 @@ static unsigned long get_target_state(struct thermal_instance *instance,
 	next_target = instance->target;
 	dev_dbg(&cdev->device, "cur_state=%ld\n", cur_state);
 
+	if (!instance->initialized) {
+		if (throttle) {
+			next_target = (cur_state + 1) >= instance->upper ?
+					instance->upper :
+					((cur_state + 1) < instance->lower ?
+					instance->lower : (cur_state + 1));
+		} else
+			next_target = THERMAL_NO_TARGET;
+	}
+
 	switch (trend) {
 	case THERMAL_TREND_RAISING:
 		if (throttle) {
@@ -149,7 +159,8 @@ static void thermal_zone_trip_update(struct thermal_zone_device *tz, int trip)
 		dev_dbg(&instance->cdev->device, "old_target=%d, target=%d\n",
 					old_target, (int)instance->target);
 
-		if (old_target == instance->target)
+		if (instance->initialized &&
+		    old_target == instance->target)
 			continue;
 
 		/* Activate a passive thermal instance */
@@ -161,7 +172,7 @@ static void thermal_zone_trip_update(struct thermal_zone_device *tz, int trip)
 			instance->target == THERMAL_NO_TARGET)
 			update_passive_instance(tz, trip_type, -1);
 
-
+		instance->initialized = true;
 		instance->cdev->updated = false; /* cdev needs update */
 	}
 
diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
index 174d3bc..9d6f71b 100644
--- a/drivers/thermal/thermal_core.c
+++ b/drivers/thermal/thermal_core.c
@@ -469,8 +469,22 @@ static void update_temperature(struct thermal_zone_device *tz)
 	mutex_unlock(&tz->lock);
 
 	trace_thermal_temperature(tz);
-	dev_dbg(&tz->device, "last_temperature=%d, current_temperature=%d\n",
-				tz->last_temperature, tz->temperature);
+	if (tz->last_temperature == THERMAL_TEMP_INVALID)
+		dev_dbg(&tz->device, "last_temperature N/A, current_temperature=%d\n",
+			tz->temperature);
+	else
+		dev_dbg(&tz->device, "last_temperature=%d, current_temperature=%d\n",
+			tz->last_temperature, tz->temperature);
+}
+
+static void thermal_zone_device_reset(struct thermal_zone_device *tz)
+{
+	struct thermal_instance *pos;
+
+	tz->temperature = THERMAL_TEMP_INVALID;
+	tz->passive = 0;
+	list_for_each_entry(pos, &tz->thermal_instances, tz_node)
+		pos->initialized = false;
 }
 
 void thermal_zone_device_update(struct thermal_zone_device *tz)
@@ -1574,6 +1588,7 @@ struct thermal_zone_device *thermal_zone_device_register(const char *type,
 	if (!tz->ops->get_temp)
 		thermal_zone_device_set_polling(tz, 0);
 
+	thermal_zone_device_reset(tz);
 	thermal_zone_device_update(tz);
 
 	return tz;
diff --git a/drivers/thermal/thermal_core.h b/drivers/thermal/thermal_core.h
index 0531c75..6d9ffa5 100644
--- a/drivers/thermal/thermal_core.h
+++ b/drivers/thermal/thermal_core.h
@@ -41,6 +41,7 @@ struct thermal_instance {
 	struct thermal_zone_device *tz;
 	struct thermal_cooling_device *cdev;
 	int trip;
+	bool initialized;
 	unsigned long upper;	/* Highest cooling state for this trip point */
 	unsigned long lower;	/* Lowest cooling state for this trip point */
 	unsigned long target;	/* expected cooling state */
diff --git a/include/linux/thermal.h b/include/linux/thermal.h
index 5eac316..fb96b15 100644
--- a/include/linux/thermal.h
+++ b/include/linux/thermal.h
@@ -40,6 +40,9 @@
 /* No upper/lower limit requirement */
 #define THERMAL_NO_LIMIT	((u32)~0)
 
+/* use value, which < 0K, to indicate an invalid/uninitialized temperature */
+#define THERMAL_TEMP_INVALID	-274000
+
 /* Unit conversion macros */
 #define KELVIN_TO_CELSIUS(t)	(long)(((long)t-2732 >= 0) ?	\
 				((long)t-2732+5)/10 : ((long)t-2732-5)/10)
-- 
1.9.1