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Commit e6e238c3 authored by Amit Daniel Kachhap's avatar Amit Daniel Kachhap Committed by Zhang Rui
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thermal: sysfs: Add a new sysfs node emul_temp for thermal emulation 



This patch adds support to set the emulated temperature method in
thermal zone (sensor). After setting this feature thermal zone may
report this temperature and not the actual temperature. The emulation
implementation may be based on sensor capability through platform
specific handler or pure software emulation if no platform handler defined.

This is useful in debugging different temperature threshold and its
associated cooling action. Critical threshold's cannot be emulated.
Writing 0 on this node should disable emulation.

Signed-off-by: default avatarAmit Daniel Kachhap <amit.daniel@samsung.com>
Acked-by: default avatarKukjin Kim <kgene.kim@samsung.com>
Signed-off-by: default avatarZhang Rui <rui.zhang@intel.com>
parent c8165dc0

Documentation/thermal/sysfs-api.txt

+13 −0
Original line number Diff line number Diff line
@@ -55,6 +55,8 @@ temperature) and throttle appropriate devices. 
	.get_trip_type: get the type of certain trip point.

	.get_trip_temp: get the temperature above which the certain trip point

			will be fired.

	.set_emul_temp: set the emulation temperature which helps in debugging

			different threshold temperature points.



1.1.2 void thermal_zone_device_unregister(struct thermal_zone_device *tz)
@@ -153,6 +155,7 @@ Thermal zone device sys I/F, created once it's registered: 
    |---trip_point_[0-*]_temp:	Trip point temperature

    |---trip_point_[0-*]_type:	Trip point type

    |---trip_point_[0-*]_hyst:	Hysteresis value for this trip point

    |---emul_temp:		Emulated temperature set node



Thermal cooling device sys I/F, created once it's registered:

/sys/class/thermal/cooling_device[0-*]:
@@ -252,6 +255,16 @@ passive 
	Valid values: 0 (disabled) or greater than 1000

	RW, Optional



emul_temp

	Interface to set the emulated temperature method in thermal zone

	(sensor). After setting this temperature, the thermal zone may pass

	this temperature to platform emulation function if registered or

	cache it locally. This is useful in debugging different temperature

	threshold and its associated cooling action. This is write only node

	and writing 0 on this node should disable emulation.

	Unit: millidegree Celsius

	WO, Optional



*****************************

* Cooling device attributes *

*****************************

drivers/thermal/Kconfig

+8 −0
Original line number Diff line number Diff line
@@ -78,6 +78,14 @@ config CPU_THERMAL 
	  and not the ACPI interface.

	  If you want this support, you should say Y here.



config THERMAL_EMULATION

	bool "Thermal emulation mode support"

	help

	  Enable this option to make a emul_temp sysfs node in thermal zone

	  directory to support temperature emulation. With emulation sysfs node,

	  user can manually input temperature and test the different trip

	  threshold behaviour for simulation purpose.



config SPEAR_THERMAL

	bool "SPEAr thermal sensor driver"

	depends on PLAT_SPEAR

drivers/thermal/thermal_sys.c

+68 −11
Original line number Diff line number Diff line
@@ -378,24 +378,54 @@ static void handle_thermal_trip(struct thermal_zone_device *tz, int trip) 
	monitor_thermal_zone(tz);

}



static int thermal_zone_get_temp(struct thermal_zone_device *tz,

				unsigned long *temp)

{

	int ret = 0, count;

	unsigned long crit_temp = -1UL;

	enum thermal_trip_type type;



	mutex_lock(&tz->lock);



	ret = tz->ops->get_temp(tz, temp);

#ifdef CONFIG_THERMAL_EMULATION

	if (!tz->emul_temperature)

		goto skip_emul;



	for (count = 0; count < tz->trips; count++) {

		ret = tz->ops->get_trip_type(tz, count, &type);

		if (!ret && type == THERMAL_TRIP_CRITICAL) {

			ret = tz->ops->get_trip_temp(tz, count, &crit_temp);

			break;

		}

	}



	if (ret)

		goto skip_emul;



	if (*temp < crit_temp)

		*temp = tz->emul_temperature;

skip_emul:

#endif

	mutex_unlock(&tz->lock);

	return ret;

}



static void update_temperature(struct thermal_zone_device *tz)

{

	long temp;

	int ret;



	mutex_lock(&tz->lock);



	ret = tz->ops->get_temp(tz, &temp);

	ret = thermal_zone_get_temp(tz, &temp);

	if (ret) {

		dev_warn(&tz->device, "failed to read out thermal zone %d\n",

			 tz->id);

		goto exit;

		return;

	}



	mutex_lock(&tz->lock);

	tz->last_temperature = tz->temperature;

	tz->temperature = temp;



exit:

	mutex_unlock(&tz->lock);

}
@@ -438,10 +468,7 @@ temp_show(struct device *dev, struct device_attribute *attr, char *buf) 
	long temperature;

	int ret;



	if (!tz->ops->get_temp)

		return -EPERM;



	ret = tz->ops->get_temp(tz, &temperature);

	ret = thermal_zone_get_temp(tz, &temperature);



	if (ret)

		return ret;
@@ -701,6 +728,31 @@ policy_show(struct device *dev, struct device_attribute *devattr, char *buf) 
	return sprintf(buf, "%s\n", tz->governor->name);

}



#ifdef CONFIG_THERMAL_EMULATION

static ssize_t

emul_temp_store(struct device *dev, struct device_attribute *attr,

		     const char *buf, size_t count)

{

	struct thermal_zone_device *tz = to_thermal_zone(dev);

	int ret = 0;

	unsigned long temperature;



	if (kstrtoul(buf, 10, &temperature))

		return -EINVAL;



	if (!tz->ops->set_emul_temp) {

		mutex_lock(&tz->lock);

		tz->emul_temperature = temperature;

		mutex_unlock(&tz->lock);

	} else {

		ret = tz->ops->set_emul_temp(tz, temperature);

	}



	return ret ? ret : count;

}

static DEVICE_ATTR(emul_temp, S_IWUSR, NULL, emul_temp_store);

#endif/*CONFIG_THERMAL_EMULATION*/



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);
@@ -843,7 +895,7 @@ temp_input_show(struct device *dev, struct device_attribute *attr, char *buf) 
				       temp_input);

	struct thermal_zone_device *tz = temp->tz;



	ret = tz->ops->get_temp(tz, &temperature);

	ret = thermal_zone_get_temp(tz, &temperature);



	if (ret)

		return ret;
@@ -1596,6 +1648,11 @@ struct thermal_zone_device *thermal_zone_device_register(const char *type, 
			goto unregister;

	}



#ifdef CONFIG_THERMAL_EMULATION

	result = device_create_file(&tz->device, &dev_attr_emul_temp);

	if (result)

		goto unregister;

#endif

	/* Create policy attribute */

	result = device_create_file(&tz->device, &dev_attr_policy);

	if (result)

include/linux/thermal.h

+2 −0
Original line number Diff line number Diff line
@@ -123,6 +123,7 @@ struct thermal_zone_device_ops { 
	int (*set_trip_hyst) (struct thermal_zone_device *, int,

			      unsigned long);

	int (*get_crit_temp) (struct thermal_zone_device *, unsigned long *);

	int (*set_emul_temp) (struct thermal_zone_device *, unsigned long);

	int (*get_trend) (struct thermal_zone_device *, int,

			  enum thermal_trend *);

	int (*notify) (struct thermal_zone_device *, int,
@@ -165,6 +166,7 @@ struct thermal_zone_device { 
	int polling_delay;

	int temperature;

	int last_temperature;

	int emul_temperature;

	int passive;

	unsigned int forced_passive;

	const struct thermal_zone_device_ops *ops;