[PATCH 51/52] Thermal: Add Hysteresis attributes

Len Brown
2012-07-25T03:43:53Z

From: Durgadoss R <dugardoss.r@intel.com>

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>
---
Documentation/thermal/sysfs-api.txt | 6 +++
drivers/thermal/thermal_sys.c | 88 ++++++++++++++++++++++++++++++++++---
include/linux/thermal.h | 5 +++
3 files changed, 94 insertions(+), 5 deletions(-)

diff --git a/Documentation/thermal/sysfs-api.txt b/Documentation/thermal/sysfs-api.txt
index 4c10593..2ba4c9b 100644
--- 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 5feb335..2d7a9fe 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);
}

/**
diff --git a/include/linux/thermal.h b/include/linux/thermal.h
index 6eaf914..cfc8d90 100644
--- 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;
--
1.7.12.rc0