[PATCHv3 2/3] thermal: expose thermal_zone_get_temp API

[Eduardo Valentin <eduardo.valentin@ti.com>]

This patch exports the thermal_zone_get_temp API so that driver
writers can fetch temperature of thermal zones managed by other
drivers.

Acked-by: Durgadoss R <durgadoss.r@intel.com>
Signed-off-by: Eduardo Valentin <eduardo.valentin@ti.com>
---
 drivers/thermal/thermal_sys.c |   20 +++++++++++++++++---
 include/linux/thermal.h       |    1 +
 2 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/drivers/thermal/thermal_sys.c b/drivers/thermal/thermal_sys.c
index e9b636b..83bfa0d 100644
--- a/drivers/thermal/thermal_sys.c
+++ b/drivers/thermal/thermal_sys.c
@@ -371,16 +371,28 @@ static void handle_thermal_trip(struct thermal_zone_device *tz, int trip)
 	monitor_thermal_zone(tz);
 }
 
-static int thermal_zone_get_temp(struct thermal_zone_device *tz,
-				unsigned long *temp)
+/**
+ * thermal_zone_get_temp() - returns its the temperature of thermal zone
+ * @tz: a valid pointer to a struct thermal_zone_device
+ * @temp: a valid pointer to where to store the resulting temperature.
+ *
+ * When a valid thermal zone reference is passed, it will fetch its
+ * temperature and fill @temp.
+ *
+ * Return: On success returns 0, an error code otherwise
+ */
+int thermal_zone_get_temp(struct thermal_zone_device *tz, unsigned long *temp)
 {
-	int ret = 0;
+	int ret = -EINVAL;
 #ifdef CONFIG_THERMAL_EMULATION
 	int count;
 	unsigned long crit_temp = -1UL;
 	enum thermal_trip_type type;
 #endif
 
+	if (IS_ERR_OR_NULL(tz))
+		goto exit;
+
 	mutex_lock(&tz->lock);
 
 	ret = tz->ops->get_temp(tz, temp);
@@ -404,8 +416,10 @@ static int thermal_zone_get_temp(struct thermal_zone_device *tz,
 skip_emul:
 #endif
 	mutex_unlock(&tz->lock);
+exit:
 	return ret;
 }
+EXPORT_SYMBOL_GPL(thermal_zone_get_temp);
 
 static void update_temperature(struct thermal_zone_device *tz)
 {
diff --git a/include/linux/thermal.h b/include/linux/thermal.h
index 0cf9eb5..8eea86c 100644
--- a/include/linux/thermal.h
+++ b/include/linux/thermal.h
@@ -238,6 +238,7 @@ struct thermal_cooling_device *thermal_cooling_device_register(char *, void *,
 		const struct thermal_cooling_device_ops *);
 void thermal_cooling_device_unregister(struct thermal_cooling_device *);
 struct thermal_zone_device *thermal_zone_get_zone_by_name(const char *name);
+int thermal_zone_get_temp(struct thermal_zone_device *tz, unsigned long *temp);
 
 int thermal_zone_trend_get(struct thermal_zone_device *, int);
 struct thermal_instance *thermal_instance_get(struct thermal_zone_device *,
-- 
1.7.7.1.488.ge8e1c