Thermal: Add Hysteresis attributes

The Linux Thermal Framework does not support hysteresis
attributes. Most thermal sensors, today, have a
hysteresis value associated with trip points.

This patch adds hysteresis attributes on a per-trip-point
basis, to the Thermal Framework. These attributes are
optionally writable.

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

diff --git a/Documentation/thermal/sysfs-api.txt b/Documentation/thermal/sysfs-api.txt
index 4c105934c59905fb9b4288ef9eab1ae31d733634..2ba4c9bb790a91f10f040e1971059ce73694719e 100644 (file)
--- a/Documentation/thermal/sysfs-api.txt
+++ b/Documentation/thermal/sysfs-api.txt
@@ -121,6 +121,7 @@ Thermal zone device sys I/F, created once it's registered:
     |---mode:                  Working mode of the thermal zone
     |---trip_point_[0-*]_temp: Trip point temperature
     |---trip_point_[0-*]_type: Trip point type
+    |---trip_point_[0-*]_hyst: Hysteresis value for this trip point
 
 Thermal cooling device sys I/F, created once it's registered:
 /sys/class/thermal/cooling_device[0-*]:
@@ -190,6 +191,11 @@ trip_point_[0-*]_type
        thermal zone.
        RO, Optional
 
+trip_point_[0-*]_hyst
+       The hysteresis value for a trip point, represented as an integer
+       Unit: Celsius
+       RW, Optional
+
 cdev[0-*]
        Sysfs link to the thermal cooling device node where the sys I/F
        for cooling device throttling control represents.

diff --git a/drivers/thermal/thermal_sys.c b/drivers/thermal/thermal_sys.c
index 5feb3353213f8c212271660a2912ff2e80cf908e..2d7a9fe8f365b64670dca63b98f925e7b0a15e73 100644 (file)
--- a/drivers/thermal/thermal_sys.c
+++ b/drivers/thermal/thermal_sys.c
@@ -239,6 +239,52 @@ trip_point_temp_show(struct device *dev, struct device_attribute *attr,
        return sprintf(buf, "%ld\n", temperature);
 }
 
+static ssize_t
+trip_point_hyst_store(struct device *dev, struct device_attribute *attr,
+                       const char *buf, size_t count)
+{
+       struct thermal_zone_device *tz = to_thermal_zone(dev);
+       int trip, ret;
+       unsigned long temperature;
+
+       if (!tz->ops->set_trip_hyst)
+               return -EPERM;
+
+       if (!sscanf(attr->attr.name, "trip_point_%d_hyst", &trip))
+               return -EINVAL;
+
+       if (kstrtoul(buf, 10, &temperature))
+               return -EINVAL;
+
+       /*
+        * We are not doing any check on the 'temperature' value
+        * here. The driver implementing 'set_trip_hyst' has to
+        * take care of this.
+        */
+       ret = tz->ops->set_trip_hyst(tz, trip, temperature);
+
+       return ret ? ret : count;
+}
+
+static ssize_t
+trip_point_hyst_show(struct device *dev, struct device_attribute *attr,
+                       char *buf)
+{
+       struct thermal_zone_device *tz = to_thermal_zone(dev);
+       int trip, ret;
+       unsigned long temperature;
+
+       if (!tz->ops->get_trip_hyst)
+               return -EPERM;
+
+       if (!sscanf(attr->attr.name, "trip_point_%d_hyst", &trip))
+               return -EINVAL;
+
+       ret = tz->ops->get_trip_hyst(tz, trip, &temperature);
+
+       return ret ? ret : sprintf(buf, "%ld\n", temperature);
+}
+
 static ssize_t
 passive_store(struct device *dev, struct device_attribute *attr,
                    const char *buf, size_t count)
@@ -1091,21 +1137,29 @@ EXPORT_SYMBOL(thermal_zone_device_update);
 static int create_trip_attrs(struct thermal_zone_device *tz, int mask)
 {
        int indx;
+       int size = sizeof(struct thermal_attr) * tz->trips;
 
-       tz->trip_type_attrs =
-               kzalloc(sizeof(struct thermal_attr) * tz->trips, GFP_KERNEL);
+       tz->trip_type_attrs = kzalloc(size, GFP_KERNEL);
        if (!tz->trip_type_attrs)
                return -ENOMEM;
 
-       tz->trip_temp_attrs =
-               kzalloc(sizeof(struct thermal_attr) * tz->trips, GFP_KERNEL);
+       tz->trip_temp_attrs = kzalloc(size, GFP_KERNEL);
        if (!tz->trip_temp_attrs) {
                kfree(tz->trip_type_attrs);
                return -ENOMEM;
        }
 
-       for (indx = 0; indx < tz->trips; indx++) {
+       if (tz->ops->get_trip_hyst) {
+               tz->trip_hyst_attrs = kzalloc(size, GFP_KERNEL);
+               if (!tz->trip_hyst_attrs) {
+                       kfree(tz->trip_type_attrs);
+                       kfree(tz->trip_temp_attrs);
+                       return -ENOMEM;
+               }
+       }
 
+
+       for (indx = 0; indx < tz->trips; indx++) {
                /* create trip type attribute */
                snprintf(tz->trip_type_attrs[indx].name, THERMAL_NAME_LENGTH,
                         "trip_point_%d_type", indx);
@@ -1136,6 +1190,26 @@ static int create_trip_attrs(struct thermal_zone_device *tz, int mask)
 
                device_create_file(&tz->device,
                                   &tz->trip_temp_attrs[indx].attr);
+
+               /* create Optional trip hyst attribute */
+               if (!tz->ops->get_trip_hyst)
+                       continue;
+               snprintf(tz->trip_hyst_attrs[indx].name, THERMAL_NAME_LENGTH,
+                        "trip_point_%d_hyst", indx);
+
+               sysfs_attr_init(&tz->trip_hyst_attrs[indx].attr.attr);
+               tz->trip_hyst_attrs[indx].attr.attr.name =
+                                       tz->trip_hyst_attrs[indx].name;
+               tz->trip_hyst_attrs[indx].attr.attr.mode = S_IRUGO;
+               tz->trip_hyst_attrs[indx].attr.show = trip_point_hyst_show;
+               if (tz->ops->set_trip_hyst) {
+                       tz->trip_hyst_attrs[indx].attr.attr.mode |= S_IWUSR;
+                       tz->trip_hyst_attrs[indx].attr.store =
+                                       trip_point_hyst_store;
+               }
+
+               device_create_file(&tz->device,
+                                  &tz->trip_hyst_attrs[indx].attr);
        }
        return 0;
 }
@@ -1149,9 +1223,13 @@ static void remove_trip_attrs(struct thermal_zone_device *tz)
                                   &tz->trip_type_attrs[indx].attr);
                device_remove_file(&tz->device,
                                   &tz->trip_temp_attrs[indx].attr);
+               if (tz->ops->get_trip_hyst)
+                       device_remove_file(&tz->device,
+                                 &tz->trip_hyst_attrs[indx].attr);
        }
        kfree(tz->trip_type_attrs);
        kfree(tz->trip_temp_attrs);
+       kfree(tz->trip_hyst_attrs);
 }
 
 /**

diff --git a/include/linux/thermal.h b/include/linux/thermal.h
index 6eaf9146c847e6cffa3497ed6cf7db44f8761dcb..cfc8d908892e849a3bb8a3336a8225bae554d0eb 100644 (file)
--- a/include/linux/thermal.h
+++ b/include/linux/thermal.h
@@ -60,6 +60,10 @@ struct thermal_zone_device_ops {
                              unsigned long *);
        int (*set_trip_temp) (struct thermal_zone_device *, int,
                              unsigned long);
+       int (*get_trip_hyst) (struct thermal_zone_device *, int,
+                             unsigned long *);
+       int (*set_trip_hyst) (struct thermal_zone_device *, int,
+                             unsigned long);
        int (*get_crit_temp) (struct thermal_zone_device *, unsigned long *);
        int (*notify) (struct thermal_zone_device *, int,
                       enum thermal_trip_type);
@@ -98,6 +102,7 @@ struct thermal_zone_device {
        struct device device;
        struct thermal_attr *trip_temp_attrs;
        struct thermal_attr *trip_type_attrs;
+       struct thermal_attr *trip_hyst_attrs;
        void *devdata;
        int trips;
        int tc1;