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>

1 files changed, 83 insertions, 5 deletions

diff --git a/drivers/thermal/thermal_sys.c b/drivers/thermal/thermal_sys.c
index 5feb3353213f..2d7a9fe8f365 100644
--- a/drivers/thermal/thermal_sys.c
+++ b/drivers/thermal/thermal_sys.c
@@ -240,6 +240,52 @@ trip_point_temp_show(struct device *dev, struct device_attribute *attr,
 }
 
 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);
 }
 
 /**