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Commit d29230b5 authored by Ram Chandrasekar's avatar Ram Chandrasekar
Browse files

drivers: of-thermal: Relate thermal zones using same sensor 



A sensor may need to be monitored by two or more thermal governors to
deploy different mitigation strategies to control the device temperature.
To achieve this the sensors driver has to register the same sensor as
multiple thermal zones and then let the different governors monitor and
mitigate. The sensor driver should handle the aggregation of thresholds,
trip notification and synchronization between thermal zones.

Add support in of-thermal to create and handle sibling thermal zones.
Thermal zones that share the same sensor are siblings. To establish a
relationship between then the sibling zones, a sensor meta data is shared
across multiple sibling thermal zones. This meta data will aid in
traversing through all the sibling thermal zones.

Change-Id: I910c0ee15b575daff8c7636a8197da72b94ae72e
Signed-off-by: default avatarRam Chandrasekar <rkumbako@codeaurora.org>
parent e34ced65

drivers/thermal/of-thermal.c

+45 −21
Original line number Diff line number Diff line
@@ -31,11 +31,16 @@ 
#include <linux/export.h>

#include <linux/string.h>

#include <linux/thermal.h>

#include <linux/list.h>



#include "thermal_core.h"



/***   Private data structures to represent thermal device tree data ***/

#define for_each_tz_sibling(pos, head)                                         \

	for (pos = list_first_entry((head), struct __thermal_zone, list);\

		&(pos->list) != (head);                                  \

		pos = list_next_entry(pos, list))                        \



/***   Private data structures to represent thermal device tree data ***/

/**

 * struct __thermal_bind_param - a match between trip and cooling device

 * @cooling_device: a pointer to identify the referred cooling device
@@ -57,10 +62,12 @@ struct __thermal_bind_params { 
 * struct __sensor_param - Holds individual sensor data

 * @sensor_data: sensor driver private data passed as input argument

 * @ops: sensor driver ops

 * @first_tz: list head pointing the first thermal zone

 */

struct __sensor_param {

	void *sensor_data;

	const struct thermal_zone_of_device_ops *ops;

	struct list_head first_tz;

};



/**
@@ -70,10 +77,12 @@ struct __sensor_param { 
 * @polling_delay: zone polling interval

 * @slope: slope of the temperature adjustment curve

 * @offset: offset of the temperature adjustment curve

 * @tzd: thermal zone device pointer for this sensor

 * @ntrips: number of trip points

 * @trips: an array of trip points (0..ntrips - 1)

 * @num_tbps: number of thermal bind params

 * @tbps: an array of thermal bind params (0..num_tbps - 1)

 * @list: sibling thermal zone pointer

 * @senps: sensor related parameters

 */
@@ -83,6 +92,7 @@ struct __thermal_zone { 
	int polling_delay;

	int slope;

	int offset;

	struct thermal_zone_device *tzd;



	/* trip data */

	int ntrips;
@@ -92,6 +102,7 @@ struct __thermal_zone { 
	int num_tbps;

	struct __thermal_bind_params *tbps;



	struct list_head list;

	/* sensor interface */

	struct __sensor_param *senps;

};
@@ -444,6 +455,7 @@ thermal_zone_of_add_sensor(struct device_node *zone, 
	if (sens_param->ops->set_emul_temp)

		tzd->ops->set_emul_temp = of_thermal_set_emul_temp;



	list_add_tail(&tz->list, &sens_param->first_tz);

	mutex_unlock(&tzd->lock);



	return tzd;
@@ -474,11 +486,10 @@ thermal_zone_of_add_sensor(struct device_node *zone, 
 * 01 - This function must enqueue the new sensor instead of using

 * it as the only source of temperature values.

 *

 * 02 - There must be a way to match the sensor with all thermal zones

 * that refer to it.

 *

 * Return: On success returns a valid struct thermal_zone_device,

 * otherwise, it returns a corresponding ERR_PTR(). Caller must

 * otherwise, it returns a corresponding ERR_PTR(). Incase there are multiple

 * thermal zones referencing the same sensor, the return value will be

 * thermal_zone_device pointer of the first thermal zone. Caller must

 * check the return value with help of IS_ERR() helper.

 */

struct thermal_zone_device *
@@ -487,6 +498,7 @@ thermal_zone_of_sensor_register(struct device *dev, int sensor_id, void *data, 
{

	struct device_node *np, *child, *sensor_np;

	struct thermal_zone_device *tzd = ERR_PTR(-ENODEV);

	struct thermal_zone_device *first_tzd = NULL;

	struct __sensor_param *sens_param = NULL;



	np = of_find_node_by_name(NULL, "thermal-zones");
@@ -505,6 +517,7 @@ thermal_zone_of_sensor_register(struct device *dev, int sensor_id, void *data, 
	}

	sens_param->sensor_data = data;

	sens_param->ops = ops;

	INIT_LIST_HEAD(&sens_param->first_tz);

	sensor_np = of_node_get(dev->of_node);



	for_each_available_child_of_node(np, child) {
@@ -530,22 +543,22 @@ thermal_zone_of_sensor_register(struct device *dev, int sensor_id, void *data, 
		if (sensor_specs.np == sensor_np && id == sensor_id) {

			tzd = thermal_zone_of_add_sensor(child, sensor_np,

							 sens_param);

			if (!IS_ERR(tzd))

			if (!IS_ERR(tzd)) {

				if (!first_tzd)

					first_tzd = tzd;

				tzd->ops->set_mode(tzd, THERMAL_DEVICE_ENABLED);



			of_node_put(sensor_specs.np);

			of_node_put(child);

			goto exit;

			}

		}

		of_node_put(sensor_specs.np);

	}

exit:

	of_node_put(sensor_np);

	of_node_put(np);



	if (tzd == ERR_PTR(-ENODEV))

	if (!first_tzd) {

		first_tzd = ERR_PTR(-ENODEV);

		kfree(sens_param);

	return tzd;

	}

	return first_tzd;

}

EXPORT_SYMBOL_GPL(thermal_zone_of_sensor_register);
@@ -568,6 +581,8 @@ void thermal_zone_of_sensor_unregister(struct device *dev, 
				       struct thermal_zone_device *tzd)

{

	struct __thermal_zone *tz;

	struct thermal_zone_device *pos;

	struct list_head *head;



	if (!dev || !tzd || !tzd->devdata)

		return;
@@ -578,14 +593,20 @@ void thermal_zone_of_sensor_unregister(struct device *dev, 
	if (!tz)

		return;



	mutex_lock(&tzd->lock);

	tzd->ops->get_temp = NULL;

	tzd->ops->get_trend = NULL;

	tzd->ops->set_emul_temp = NULL;

	head = &tz->senps->first_tz;

	for_each_tz_sibling(tz, head) {

		pos = tz->tzd;

		mutex_lock(&pos->lock);

		pos->ops->get_temp = NULL;

		pos->ops->get_trend = NULL;

		pos->ops->set_emul_temp = NULL;



		list_del(&tz->list);

		if (list_empty(&tz->senps->first_tz))

			kfree(tz->senps);

		tz->senps = NULL;

	mutex_unlock(&tzd->lock);

		mutex_unlock(&pos->lock);

	}

}

EXPORT_SYMBOL_GPL(thermal_zone_of_sensor_unregister);
@@ -854,6 +875,7 @@ __init *thermal_of_build_thermal_zone(struct device_node *np) 
	if (!tz)

		return ERR_PTR(-ENOMEM);



	INIT_LIST_HEAD(&tz->list);

	ret = of_property_read_u32(np, "polling-delay-passive", &prop);

	if (ret < 0) {

		pr_err("missing polling-delay-passive property\n");
@@ -1044,7 +1066,9 @@ int __init of_parse_thermal_zones(void) 
			kfree(ops);

			of_thermal_free_zone(tz);

			/* attempting to build remaining zones still */

			continue;

		}

		tz->tzd = zone;

	}

	of_node_put(np);