Thermal: Add a policy sysfs attribute

This patch adds a policy sysfs attribute to a thermal zone.
This attribute denotes the throttling governor used for the
zone. This is a RW attribute.

Signed-off-by: Durgadoss R <durgadoss.r@intel.com>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>

1 files changed, 39 insertions, 3 deletions

diff --git a/drivers/thermal/thermal_sys.c b/drivers/thermal/thermal_sys.c
index 0afd84cb127d..a6933dad3bab 100644
--- a/drivers/thermal/thermal_sys.c
+++ b/drivers/thermal/thermal_sys.c
@@ -454,10 +454,41 @@ passive_show(struct device *dev, struct device_attribute *attr,
         return sprintf(buf, "%d\n", tz->forced_passive);
 }
 
+static ssize_t
+policy_store(struct device *dev, struct device_attribute *attr,
+                    const char *buf, size_t count)
+{
+        int ret = -EINVAL;
+        struct thermal_zone_device *tz = to_thermal_zone(dev);
+        struct thermal_governor *gov;
+
+        mutex_lock(&thermal_governor_lock);
+
+        gov = __find_governor(buf);
+        if (!gov)
+                goto exit;
+
+        tz->governor = gov;
+        ret = count;
+
+exit:
+        mutex_unlock(&thermal_governor_lock);
+        return ret;
+}
+
+static ssize_t
+policy_show(struct device *dev, struct device_attribute *devattr, char *buf)
+{
+        struct thermal_zone_device *tz = to_thermal_zone(dev);
+
+        return sprintf(buf, "%s\n", tz->governor->name);
+}
+
 static DEVICE_ATTR(type, 0444, type_show, NULL);
 static DEVICE_ATTR(temp, 0444, temp_show, NULL);
 static DEVICE_ATTR(mode, 0644, mode_show, mode_store);
 static DEVICE_ATTR(passive, S_IRUGO | S_IWUSR, passive_show, passive_store);
+static DEVICE_ATTR(policy, S_IRUGO | S_IWUSR, policy_show, policy_store);
 
 /* sys I/F for cooling device */
 #define to_cooling_device(_dev) \
@@ -1509,10 +1540,14 @@ struct thermal_zone_device *thermal_zone_device_register(const char *type,
                         passive = 1;
         }
 
-        if (!passive)
-                result = device_create_file(&tz->device,
-                                            &dev_attr_passive);
+        if (!passive) {
+                result = device_create_file(&tz->device, &dev_attr_passive);
+                if (result)
+                        goto unregister;
+        }
 
+        /* Create policy attribute */
+        result = device_create_file(&tz->device, &dev_attr_policy);
         if (result)
                 goto unregister;
 
@@ -1588,6 +1623,7 @@ void thermal_zone_device_unregister(struct thermal_zone_device *tz)
         device_remove_file(&tz->device, &dev_attr_temp);
         if (tz->ops->get_mode)
                 device_remove_file(&tz->device, &dev_attr_mode);
+        device_remove_file(&tz->device, &dev_attr_policy);
         remove_trip_attrs(tz);
         tz->governor = NULL;