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Commit 27365a6c authored by Durgadoss R's avatar Durgadoss R Committed by Len Brown
Browse files

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: default avatarDurgadoss R <durgadoss.r@intel.com>
Signed-off-by: default avatarZhang Rui <rui.zhang@intel.com>
Signed-off-by: default avatarLen Brown <len.brown@intel.com>
parent c56f5c03

Documentation/thermal/sysfs-api.txt

+6 −0
Original line number Diff line number Diff line
@@ -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.

drivers/thermal/thermal_sys.c

+83 −5
Original line number Diff line number Diff line
@@ -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);

}



/**

include/linux/thermal.h

+5 −0
Original line number Diff line number Diff line
@@ -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;