Adding upstream version 4.19.249.upstream/4.19.249upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1054 insertions, 0 deletions

diff --git a/drivers/thermal/of-thermal.c b/drivers/thermal/of-thermal.c
new file mode 100644
index 000000000..4f2816559
--- /dev/null
+++ b/drivers/thermal/of-thermal.c
@@ -0,0 +1,1054 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  of-thermal.c - Generic Thermal Management device tree support.
+ *
+ *  Copyright (C) 2013 Texas Instruments
+ *  Copyright (C) 2013 Eduardo Valentin <eduardo.valentin@ti.com>
+ */
+#include <linux/thermal.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <linux/of_device.h>
+#include <linux/of_platform.h>
+#include <linux/err.h>
+#include <linux/export.h>
+#include <linux/string.h>
+
+#include "thermal_core.h"
+
+/***   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
+ * @trip_id: the trip point index
+ * @usage: the percentage (from 0 to 100) of cooling contribution
+ * @min: minimum cooling state used at this trip point
+ * @max: maximum cooling state used at this trip point
+ */
+
+struct __thermal_bind_params {
+	struct device_node *cooling_device;
+	unsigned int trip_id;
+	unsigned int usage;
+	unsigned long min;
+	unsigned long max;
+};
+
+/**
+ * struct __thermal_zone - internal representation of a thermal zone
+ * @mode: current thermal zone device mode (enabled/disabled)
+ * @passive_delay: polling interval while passive cooling is activated
+ * @polling_delay: zone polling interval
+ * @slope: slope of the temperature adjustment curve
+ * @offset: offset of the temperature adjustment curve
+ * @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)
+ * @sensor_data: sensor private data used while reading temperature and trend
+ * @ops: set of callbacks to handle the thermal zone based on DT
+ */
+
+struct __thermal_zone {
+	enum thermal_device_mode mode;
+	int passive_delay;
+	int polling_delay;
+	int slope;
+	int offset;
+
+	/* trip data */
+	int ntrips;
+	struct thermal_trip *trips;
+
+	/* cooling binding data */
+	int num_tbps;
+	struct __thermal_bind_params *tbps;
+
+	/* sensor interface */
+	void *sensor_data;
+	const struct thermal_zone_of_device_ops *ops;
+};
+
+/***   DT thermal zone device callbacks   ***/
+
+static int of_thermal_get_temp(struct thermal_zone_device *tz,
+			       int *temp)
+{
+	struct __thermal_zone *data = tz->devdata;
+
+	if (!data->ops->get_temp)
+		return -EINVAL;
+
+	return data->ops->get_temp(data->sensor_data, temp);
+}
+
+static int of_thermal_set_trips(struct thermal_zone_device *tz,
+				int low, int high)
+{
+	struct __thermal_zone *data = tz->devdata;
+
+	if (!data->ops || !data->ops->set_trips)
+		return -EINVAL;
+
+	return data->ops->set_trips(data->sensor_data, low, high);
+}
+
+/**
+ * of_thermal_get_ntrips - function to export number of available trip
+ *			   points.
+ * @tz: pointer to a thermal zone
+ *
+ * This function is a globally visible wrapper to get number of trip points
+ * stored in the local struct __thermal_zone
+ *
+ * Return: number of available trip points, -ENODEV when data not available
+ */
+int of_thermal_get_ntrips(struct thermal_zone_device *tz)
+{
+	struct __thermal_zone *data = tz->devdata;
+
+	if (!data || IS_ERR(data))
+		return -ENODEV;
+
+	return data->ntrips;
+}
+EXPORT_SYMBOL_GPL(of_thermal_get_ntrips);
+
+/**
+ * of_thermal_is_trip_valid - function to check if trip point is valid
+ *
+ * @tz:	pointer to a thermal zone
+ * @trip:	trip point to evaluate
+ *
+ * This function is responsible for checking if passed trip point is valid
+ *
+ * Return: true if trip point is valid, false otherwise
+ */
+bool of_thermal_is_trip_valid(struct thermal_zone_device *tz, int trip)
+{
+	struct __thermal_zone *data = tz->devdata;
+
+	if (!data || trip >= data->ntrips || trip < 0)
+		return false;
+
+	return true;
+}
+EXPORT_SYMBOL_GPL(of_thermal_is_trip_valid);
+
+/**
+ * of_thermal_get_trip_points - function to get access to a globally exported
+ *				trip points
+ *
+ * @tz:	pointer to a thermal zone
+ *
+ * This function provides a pointer to trip points table
+ *
+ * Return: pointer to trip points table, NULL otherwise
+ */
+const struct thermal_trip *
+of_thermal_get_trip_points(struct thermal_zone_device *tz)
+{
+	struct __thermal_zone *data = tz->devdata;
+
+	if (!data)
+		return NULL;
+
+	return data->trips;
+}
+EXPORT_SYMBOL_GPL(of_thermal_get_trip_points);
+
+/**
+ * of_thermal_set_emul_temp - function to set emulated temperature
+ *
+ * @tz:	pointer to a thermal zone
+ * @temp:	temperature to set
+ *
+ * This function gives the ability to set emulated value of temperature,
+ * which is handy for debugging
+ *
+ * Return: zero on success, error code otherwise
+ */
+static int of_thermal_set_emul_temp(struct thermal_zone_device *tz,
+				    int temp)
+{
+	struct __thermal_zone *data = tz->devdata;
+
+	return data->ops->set_emul_temp(data->sensor_data, temp);
+}
+
+static int of_thermal_get_trend(struct thermal_zone_device *tz, int trip,
+				enum thermal_trend *trend)
+{
+	struct __thermal_zone *data = tz->devdata;
+
+	if (!data->ops->get_trend)
+		return -EINVAL;
+
+	return data->ops->get_trend(data->sensor_data, trip, trend);
+}
+
+static int of_thermal_bind(struct thermal_zone_device *thermal,
+			   struct thermal_cooling_device *cdev)
+{
+	struct __thermal_zone *data = thermal->devdata;
+	int i;
+
+	if (!data || IS_ERR(data))
+		return -ENODEV;
+
+	/* find where to bind */
+	for (i = 0; i < data->num_tbps; i++) {
+		struct __thermal_bind_params *tbp = data->tbps + i;
+
+		if (tbp->cooling_device == cdev->np) {
+			int ret;
+
+			ret = thermal_zone_bind_cooling_device(thermal,
+						tbp->trip_id, cdev,
+						tbp->max,
+						tbp->min,
+						tbp->usage);
+			if (ret)
+				return ret;
+		}
+	}
+
+	return 0;
+}
+
+static int of_thermal_unbind(struct thermal_zone_device *thermal,
+			     struct thermal_cooling_device *cdev)
+{
+	struct __thermal_zone *data = thermal->devdata;
+	int i;
+
+	if (!data || IS_ERR(data))
+		return -ENODEV;
+
+	/* find where to unbind */
+	for (i = 0; i < data->num_tbps; i++) {
+		struct __thermal_bind_params *tbp = data->tbps + i;
+
+		if (tbp->cooling_device == cdev->np) {
+			int ret;
+
+			ret = thermal_zone_unbind_cooling_device(thermal,
+						tbp->trip_id, cdev);
+			if (ret)
+				return ret;
+		}
+	}
+
+	return 0;
+}
+
+static int of_thermal_get_mode(struct thermal_zone_device *tz,
+			       enum thermal_device_mode *mode)
+{
+	struct __thermal_zone *data = tz->devdata;
+
+	*mode = data->mode;
+
+	return 0;
+}
+
+static int of_thermal_set_mode(struct thermal_zone_device *tz,
+			       enum thermal_device_mode mode)
+{
+	struct __thermal_zone *data = tz->devdata;
+
+	mutex_lock(&tz->lock);
+
+	if (mode == THERMAL_DEVICE_ENABLED) {
+		tz->polling_delay = data->polling_delay;
+		tz->passive_delay = data->passive_delay;
+	} else {
+		tz->polling_delay = 0;
+		tz->passive_delay = 0;
+	}
+
+	mutex_unlock(&tz->lock);
+
+	data->mode = mode;
+	thermal_zone_device_update(tz, THERMAL_EVENT_UNSPECIFIED);
+
+	return 0;
+}
+
+static int of_thermal_get_trip_type(struct thermal_zone_device *tz, int trip,
+				    enum thermal_trip_type *type)
+{
+	struct __thermal_zone *data = tz->devdata;
+
+	if (trip >= data->ntrips || trip < 0)
+		return -EDOM;
+
+	*type = data->trips[trip].type;
+
+	return 0;
+}
+
+static int of_thermal_get_trip_temp(struct thermal_zone_device *tz, int trip,
+				    int *temp)
+{
+	struct __thermal_zone *data = tz->devdata;
+
+	if (trip >= data->ntrips || trip < 0)
+		return -EDOM;
+
+	*temp = data->trips[trip].temperature;
+
+	return 0;
+}
+
+static int of_thermal_set_trip_temp(struct thermal_zone_device *tz, int trip,
+				    int temp)
+{
+	struct __thermal_zone *data = tz->devdata;
+
+	if (trip >= data->ntrips || trip < 0)
+		return -EDOM;
+
+	if (data->ops->set_trip_temp) {
+		int ret;
+
+		ret = data->ops->set_trip_temp(data->sensor_data, trip, temp);
+		if (ret)
+			return ret;
+	}
+
+	/* thermal framework should take care of data->mask & (1 << trip) */
+	data->trips[trip].temperature = temp;
+
+	return 0;
+}
+
+static int of_thermal_get_trip_hyst(struct thermal_zone_device *tz, int trip,
+				    int *hyst)
+{
+	struct __thermal_zone *data = tz->devdata;
+
+	if (trip >= data->ntrips || trip < 0)
+		return -EDOM;
+
+	*hyst = data->trips[trip].hysteresis;
+
+	return 0;
+}
+
+static int of_thermal_set_trip_hyst(struct thermal_zone_device *tz, int trip,
+				    int hyst)
+{
+	struct __thermal_zone *data = tz->devdata;
+
+	if (trip >= data->ntrips || trip < 0)
+		return -EDOM;
+
+	/* thermal framework should take care of data->mask & (1 << trip) */
+	data->trips[trip].hysteresis = hyst;
+
+	return 0;
+}
+
+static int of_thermal_get_crit_temp(struct thermal_zone_device *tz,
+				    int *temp)
+{
+	struct __thermal_zone *data = tz->devdata;
+	int i;
+
+	for (i = 0; i < data->ntrips; i++)
+		if (data->trips[i].type == THERMAL_TRIP_CRITICAL) {
+			*temp = data->trips[i].temperature;
+			return 0;
+		}
+
+	return -EINVAL;
+}
+
+static struct thermal_zone_device_ops of_thermal_ops = {
+	.get_mode = of_thermal_get_mode,
+	.set_mode = of_thermal_set_mode,
+
+	.get_trip_type = of_thermal_get_trip_type,
+	.get_trip_temp = of_thermal_get_trip_temp,
+	.set_trip_temp = of_thermal_set_trip_temp,
+	.get_trip_hyst = of_thermal_get_trip_hyst,
+	.set_trip_hyst = of_thermal_set_trip_hyst,
+	.get_crit_temp = of_thermal_get_crit_temp,
+
+	.bind = of_thermal_bind,
+	.unbind = of_thermal_unbind,
+};
+
+/***   sensor API   ***/
+
+static struct thermal_zone_device *
+thermal_zone_of_add_sensor(struct device_node *zone,
+			   struct device_node *sensor, void *data,
+			   const struct thermal_zone_of_device_ops *ops)
+{
+	struct thermal_zone_device *tzd;
+	struct __thermal_zone *tz;
+
+	tzd = thermal_zone_get_zone_by_name(zone->name);
+	if (IS_ERR(tzd))
+		return ERR_PTR(-EPROBE_DEFER);
+
+	tz = tzd->devdata;
+
+	if (!ops)
+		return ERR_PTR(-EINVAL);
+
+	mutex_lock(&tzd->lock);
+	tz->ops = ops;
+	tz->sensor_data = data;
+
+	tzd->ops->get_temp = of_thermal_get_temp;
+	tzd->ops->get_trend = of_thermal_get_trend;
+
+	/*
+	 * The thermal zone core will calculate the window if they have set the
+	 * optional set_trips pointer.
+	 */
+	if (ops->set_trips)
+		tzd->ops->set_trips = of_thermal_set_trips;
+
+	if (ops->set_emul_temp)
+		tzd->ops->set_emul_temp = of_thermal_set_emul_temp;
+
+	mutex_unlock(&tzd->lock);
+
+	return tzd;
+}
+
+/**
+ * thermal_zone_of_sensor_register - registers a sensor to a DT thermal zone
+ * @dev: a valid struct device pointer of a sensor device. Must contain
+ *       a valid .of_node, for the sensor node.
+ * @sensor_id: a sensor identifier, in case the sensor IP has more
+ *             than one sensors
+ * @data: a private pointer (owned by the caller) that will be passed
+ *        back, when a temperature reading is needed.
+ * @ops: struct thermal_zone_of_device_ops *. Must contain at least .get_temp.
+ *
+ * This function will search the list of thermal zones described in device
+ * tree and look for the zone that refer to the sensor device pointed by
+ * @dev->of_node as temperature providers. For the zone pointing to the
+ * sensor node, the sensor will be added to the DT thermal zone device.
+ *
+ * The thermal zone temperature is provided by the @get_temp function
+ * pointer. When called, it will have the private pointer @data back.
+ *
+ * The thermal zone temperature trend is provided by the @get_trend function
+ * pointer. When called, it will have the private pointer @data back.
+ *
+ * TODO:
+ * 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
+ * check the return value with help of IS_ERR() helper.
+ */
+struct thermal_zone_device *
+thermal_zone_of_sensor_register(struct device *dev, int sensor_id, void *data,
+				const struct thermal_zone_of_device_ops *ops)
+{
+	struct device_node *np, *child, *sensor_np;
+	struct thermal_zone_device *tzd = ERR_PTR(-ENODEV);
+
+	np = of_find_node_by_name(NULL, "thermal-zones");
+	if (!np)
+		return ERR_PTR(-ENODEV);
+
+	if (!dev || !dev->of_node) {
+		of_node_put(np);
+		return ERR_PTR(-EINVAL);
+	}
+
+	sensor_np = of_node_get(dev->of_node);
+
+	for_each_available_child_of_node(np, child) {
+		struct of_phandle_args sensor_specs;
+		int ret, id;
+
+		/* For now, thermal framework supports only 1 sensor per zone */
+		ret = of_parse_phandle_with_args(child, "thermal-sensors",
+						 "#thermal-sensor-cells",
+						 0, &sensor_specs);
+		if (ret)
+			continue;
+
+		if (sensor_specs.args_count >= 1) {
+			id = sensor_specs.args[0];
+			WARN(sensor_specs.args_count > 1,
+			     "%s: too many cells in sensor specifier %d\n",
+			     sensor_specs.np->name, sensor_specs.args_count);
+		} else {
+			id = 0;
+		}
+
+		if (sensor_specs.np == sensor_np && id == sensor_id) {
+			tzd = thermal_zone_of_add_sensor(child, sensor_np,
+							 data, ops);
+			if (!IS_ERR(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);
+
+	return tzd;
+}
+EXPORT_SYMBOL_GPL(thermal_zone_of_sensor_register);
+
+/**
+ * thermal_zone_of_sensor_unregister - unregisters a sensor from a DT thermal zone
+ * @dev: a valid struct device pointer of a sensor device. Must contain
+ *       a valid .of_node, for the sensor node.
+ * @tzd: a pointer to struct thermal_zone_device where the sensor is registered.
+ *
+ * This function removes the sensor callbacks and private data from the
+ * thermal zone device registered with thermal_zone_of_sensor_register()
+ * API. It will also silent the zone by remove the .get_temp() and .get_trend()
+ * thermal zone device callbacks.
+ *
+ * TODO: When the support to several sensors per zone is added, this
+ * function must search the sensor list based on @dev parameter.
+ *
+ */
+void thermal_zone_of_sensor_unregister(struct device *dev,
+				       struct thermal_zone_device *tzd)
+{
+	struct __thermal_zone *tz;
+
+	if (!dev || !tzd || !tzd->devdata)
+		return;
+
+	tz = tzd->devdata;
+
+	/* no __thermal_zone, nothing to be done */
+	if (!tz)
+		return;
+
+	mutex_lock(&tzd->lock);
+	tzd->ops->get_temp = NULL;
+	tzd->ops->get_trend = NULL;
+	tzd->ops->set_emul_temp = NULL;
+
+	tz->ops = NULL;
+	tz->sensor_data = NULL;
+	mutex_unlock(&tzd->lock);
+}
+EXPORT_SYMBOL_GPL(thermal_zone_of_sensor_unregister);
+
+static void devm_thermal_zone_of_sensor_release(struct device *dev, void *res)
+{
+	thermal_zone_of_sensor_unregister(dev,
+					  *(struct thermal_zone_device **)res);
+}
+
+static int devm_thermal_zone_of_sensor_match(struct device *dev, void *res,
+					     void *data)
+{
+	struct thermal_zone_device **r = res;
+
+	if (WARN_ON(!r || !*r))
+		return 0;
+
+	return *r == data;
+}
+
+/**
+ * devm_thermal_zone_of_sensor_register - Resource managed version of
+ *				thermal_zone_of_sensor_register()
+ * @dev: a valid struct device pointer of a sensor device. Must contain
+ *       a valid .of_node, for the sensor node.
+ * @sensor_id: a sensor identifier, in case the sensor IP has more
+ *	       than one sensors
+ * @data: a private pointer (owned by the caller) that will be passed
+ *	  back, when a temperature reading is needed.
+ * @ops: struct thermal_zone_of_device_ops *. Must contain at least .get_temp.
+ *
+ * Refer thermal_zone_of_sensor_register() for more details.
+ *
+ * Return: On success returns a valid struct thermal_zone_device,
+ * otherwise, it returns a corresponding ERR_PTR(). Caller must
+ * check the return value with help of IS_ERR() helper.
+ * Registered thermal_zone_device device will automatically be
+ * released when device is unbounded.
+ */
+struct thermal_zone_device *devm_thermal_zone_of_sensor_register(
+	struct device *dev, int sensor_id,
+	void *data, const struct thermal_zone_of_device_ops *ops)
+{
+	struct thermal_zone_device **ptr, *tzd;
+
+	ptr = devres_alloc(devm_thermal_zone_of_sensor_release, sizeof(*ptr),
+			   GFP_KERNEL);
+	if (!ptr)
+		return ERR_PTR(-ENOMEM);
+
+	tzd = thermal_zone_of_sensor_register(dev, sensor_id, data, ops);
+	if (IS_ERR(tzd)) {
+		devres_free(ptr);
+		return tzd;
+	}
+
+	*ptr = tzd;
+	devres_add(dev, ptr);
+
+	return tzd;
+}
+EXPORT_SYMBOL_GPL(devm_thermal_zone_of_sensor_register);
+
+/**
+ * devm_thermal_zone_of_sensor_unregister - Resource managed version of
+ *				thermal_zone_of_sensor_unregister().
+ * @dev: Device for which which resource was allocated.
+ * @tzd: a pointer to struct thermal_zone_device where the sensor is registered.
+ *
+ * This function removes the sensor callbacks and private data from the
+ * thermal zone device registered with devm_thermal_zone_of_sensor_register()
+ * API. It will also silent the zone by remove the .get_temp() and .get_trend()
+ * thermal zone device callbacks.
+ * Normally this function will not need to be called and the resource
+ * management code will ensure that the resource is freed.
+ */
+void devm_thermal_zone_of_sensor_unregister(struct device *dev,
+					    struct thermal_zone_device *tzd)
+{
+	WARN_ON(devres_release(dev, devm_thermal_zone_of_sensor_release,
+			       devm_thermal_zone_of_sensor_match, tzd));
+}
+EXPORT_SYMBOL_GPL(devm_thermal_zone_of_sensor_unregister);
+
+/***   functions parsing device tree nodes   ***/
+
+/**
+ * thermal_of_populate_bind_params - parse and fill cooling map data
+ * @np: DT node containing a cooling-map node
+ * @__tbp: data structure to be filled with cooling map info
+ * @trips: array of thermal zone trip points
+ * @ntrips: number of trip points inside trips.
+ *
+ * This function parses a cooling-map type of node represented by
+ * @np parameter and fills the read data into @__tbp data structure.
+ * It needs the already parsed array of trip points of the thermal zone
+ * in consideration.
+ *
+ * Return: 0 on success, proper error code otherwise
+ */
+static int thermal_of_populate_bind_params(struct device_node *np,
+					   struct __thermal_bind_params *__tbp,
+					   struct thermal_trip *trips,
+					   int ntrips)
+{
+	struct of_phandle_args cooling_spec;
+	struct device_node *trip;
+	int ret, i;
+	u32 prop;
+
+	/* Default weight. Usage is optional */
+	__tbp->usage = THERMAL_WEIGHT_DEFAULT;
+	ret = of_property_read_u32(np, "contribution", &prop);
+	if (ret == 0)
+		__tbp->usage = prop;
+
+	trip = of_parse_phandle(np, "trip", 0);
+	if (!trip) {
+		pr_err("missing trip property\n");
+		return -ENODEV;
+	}
+
+	/* match using device_node */
+	for (i = 0; i < ntrips; i++)
+		if (trip == trips[i].np) {
+			__tbp->trip_id = i;
+			break;
+		}
+
+	if (i == ntrips) {
+		ret = -ENODEV;
+		goto end;
+	}
+
+	ret = of_parse_phandle_with_args(np, "cooling-device", "#cooling-cells",
+					 0, &cooling_spec);
+	if (ret < 0) {
+		pr_err("missing cooling_device property\n");
+		goto end;
+	}
+	__tbp->cooling_device = cooling_spec.np;
+	if (cooling_spec.args_count >= 2) { /* at least min and max */
+		__tbp->min = cooling_spec.args[0];
+		__tbp->max = cooling_spec.args[1];
+	} else {
+		pr_err("wrong reference to cooling device, missing limits\n");
+	}
+
+end:
+	of_node_put(trip);
+
+	return ret;
+}
+
+/**
+ * It maps 'enum thermal_trip_type' found in include/linux/thermal.h
+ * into the device tree binding of 'trip', property type.
+ */
+static const char * const trip_types[] = {
+	[THERMAL_TRIP_ACTIVE]	= "active",
+	[THERMAL_TRIP_PASSIVE]	= "passive",
+	[THERMAL_TRIP_HOT]	= "hot",
+	[THERMAL_TRIP_CRITICAL]	= "critical",
+};
+
+/**
+ * thermal_of_get_trip_type - Get phy mode for given device_node
+ * @np:	Pointer to the given device_node
+ * @type: Pointer to resulting trip type
+ *
+ * The function gets trip type string from property 'type',
+ * and store its index in trip_types table in @type,
+ *
+ * Return: 0 on success, or errno in error case.
+ */
+static int thermal_of_get_trip_type(struct device_node *np,
+				    enum thermal_trip_type *type)
+{
+	const char *t;
+	int err, i;
+
+	err = of_property_read_string(np, "type", &t);
+	if (err < 0)
+		return err;
+
+	for (i = 0; i < ARRAY_SIZE(trip_types); i++)
+		if (!strcasecmp(t, trip_types[i])) {
+			*type = i;
+			return 0;
+		}
+
+	return -ENODEV;
+}
+
+/**
+ * thermal_of_populate_trip - parse and fill one trip point data
+ * @np: DT node containing a trip point node
+ * @trip: trip point data structure to be filled up
+ *
+ * This function parses a trip point type of node represented by
+ * @np parameter and fills the read data into @trip data structure.
+ *
+ * Return: 0 on success, proper error code otherwise
+ */
+static int thermal_of_populate_trip(struct device_node *np,
+				    struct thermal_trip *trip)
+{
+	int prop;
+	int ret;
+
+	ret = of_property_read_u32(np, "temperature", &prop);
+	if (ret < 0) {
+		pr_err("missing temperature property\n");
+		return ret;
+	}
+	trip->temperature = prop;
+
+	ret = of_property_read_u32(np, "hysteresis", &prop);
+	if (ret < 0) {
+		pr_err("missing hysteresis property\n");
+		return ret;
+	}
+	trip->hysteresis = prop;
+
+	ret = thermal_of_get_trip_type(np, &trip->type);
+	if (ret < 0) {
+		pr_err("wrong trip type property\n");
+		return ret;
+	}
+
+	/* Required for cooling map matching */
+	trip->np = np;
+	of_node_get(np);
+
+	return 0;
+}
+
+/**
+ * thermal_of_build_thermal_zone - parse and fill one thermal zone data
+ * @np: DT node containing a thermal zone node
+ *
+ * This function parses a thermal zone type of node represented by
+ * @np parameter and fills the read data into a __thermal_zone data structure
+ * and return this pointer.
+ *
+ * TODO: Missing properties to parse: thermal-sensor-names
+ *
+ * Return: On success returns a valid struct __thermal_zone,
+ * otherwise, it returns a corresponding ERR_PTR(). Caller must
+ * check the return value with help of IS_ERR() helper.
+ */
+static struct __thermal_zone
+__init *thermal_of_build_thermal_zone(struct device_node *np)
+{
+	struct device_node *child = NULL, *gchild;
+	struct __thermal_zone *tz;
+	int ret, i;
+	u32 prop, coef[2];
+
+	if (!np) {
+		pr_err("no thermal zone np\n");
+		return ERR_PTR(-EINVAL);
+	}
+
+	tz = kzalloc(sizeof(*tz), GFP_KERNEL);
+	if (!tz)
+		return ERR_PTR(-ENOMEM);
+
+	ret = of_property_read_u32(np, "polling-delay-passive", &prop);
+	if (ret < 0) {
+		pr_err("missing polling-delay-passive property\n");
+		goto free_tz;
+	}
+	tz->passive_delay = prop;
+
+	ret = of_property_read_u32(np, "polling-delay", &prop);
+	if (ret < 0) {
+		pr_err("missing polling-delay property\n");
+		goto free_tz;
+	}
+	tz->polling_delay = prop;
+
+	/*
+	 * REVIST: for now, the thermal framework supports only
+	 * one sensor per thermal zone. Thus, we are considering
+	 * only the first two values as slope and offset.
+	 */
+	ret = of_property_read_u32_array(np, "coefficients", coef, 2);
+	if (ret == 0) {
+		tz->slope = coef[0];
+		tz->offset = coef[1];
+	} else {
+		tz->slope = 1;
+		tz->offset = 0;
+	}
+
+	/* trips */
+	child = of_get_child_by_name(np, "trips");
+
+	/* No trips provided */
+	if (!child)
+		goto finish;
+
+	tz->ntrips = of_get_child_count(child);
+	if (tz->ntrips == 0) /* must have at least one child */
+		goto finish;
+
+	tz->trips = kcalloc(tz->ntrips, sizeof(*tz->trips), GFP_KERNEL);
+	if (!tz->trips) {
+		ret = -ENOMEM;
+		goto free_tz;
+	}
+
+	i = 0;
+	for_each_child_of_node(child, gchild) {
+		ret = thermal_of_populate_trip(gchild, &tz->trips[i++]);
+		if (ret)
+			goto free_trips;
+	}
+
+	of_node_put(child);
+
+	/* cooling-maps */
+	child = of_get_child_by_name(np, "cooling-maps");
+
+	/* cooling-maps not provided */
+	if (!child)
+		goto finish;
+
+	tz->num_tbps = of_get_child_count(child);
+	if (tz->num_tbps == 0)
+		goto finish;
+
+	tz->tbps = kcalloc(tz->num_tbps, sizeof(*tz->tbps), GFP_KERNEL);
+	if (!tz->tbps) {
+		ret = -ENOMEM;
+		goto free_trips;
+	}
+
+	i = 0;
+	for_each_child_of_node(child, gchild) {
+		ret = thermal_of_populate_bind_params(gchild, &tz->tbps[i++],
+						      tz->trips, tz->ntrips);
+		if (ret)
+			goto free_tbps;
+	}
+
+finish:
+	of_node_put(child);
+	tz->mode = THERMAL_DEVICE_DISABLED;
+
+	return tz;
+
+free_tbps:
+	for (i = i - 1; i >= 0; i--)
+		of_node_put(tz->tbps[i].cooling_device);
+	kfree(tz->tbps);
+free_trips:
+	for (i = 0; i < tz->ntrips; i++)
+		of_node_put(tz->trips[i].np);
+	kfree(tz->trips);
+	of_node_put(gchild);
+free_tz:
+	kfree(tz);
+	of_node_put(child);
+
+	return ERR_PTR(ret);
+}
+
+static inline void of_thermal_free_zone(struct __thermal_zone *tz)
+{
+	int i;
+
+	for (i = 0; i < tz->num_tbps; i++)
+		of_node_put(tz->tbps[i].cooling_device);
+	kfree(tz->tbps);
+	for (i = 0; i < tz->ntrips; i++)
+		of_node_put(tz->trips[i].np);
+	kfree(tz->trips);
+	kfree(tz);
+}
+
+/**
+ * of_parse_thermal_zones - parse device tree thermal data
+ *
+ * Initialization function that can be called by machine initialization
+ * code to parse thermal data and populate the thermal framework
+ * with hardware thermal zones info. This function only parses thermal zones.
+ * Cooling devices and sensor devices nodes are supposed to be parsed
+ * by their respective drivers.
+ *
+ * Return: 0 on success, proper error code otherwise
+ *
+ */
+int __init of_parse_thermal_zones(void)
+{
+	struct device_node *np, *child;
+	struct __thermal_zone *tz;
+	struct thermal_zone_device_ops *ops;
+
+	np = of_find_node_by_name(NULL, "thermal-zones");
+	if (!np) {
+		pr_debug("unable to find thermal zones\n");
+		return 0; /* Run successfully on systems without thermal DT */
+	}
+
+	for_each_available_child_of_node(np, child) {
+		struct thermal_zone_device *zone;
+		struct thermal_zone_params *tzp;
+		int i, mask = 0;
+		u32 prop;
+
+		tz = thermal_of_build_thermal_zone(child);
+		if (IS_ERR(tz)) {
+			pr_err("failed to build thermal zone %s: %ld\n",
+			       child->name,
+			       PTR_ERR(tz));
+			continue;
+		}
+
+		ops = kmemdup(&of_thermal_ops, sizeof(*ops), GFP_KERNEL);
+		if (!ops)
+			goto exit_free;
+
+		tzp = kzalloc(sizeof(*tzp), GFP_KERNEL);
+		if (!tzp) {
+			kfree(ops);
+			goto exit_free;
+		}
+
+		/* No hwmon because there might be hwmon drivers registering */
+		tzp->no_hwmon = true;
+
+		if (!of_property_read_u32(child, "sustainable-power", &prop))
+			tzp->sustainable_power = prop;
+
+		for (i = 0; i < tz->ntrips; i++)
+			mask |= 1 << i;
+
+		/* these two are left for temperature drivers to use */
+		tzp->slope = tz->slope;
+		tzp->offset = tz->offset;
+
+		zone = thermal_zone_device_register(child->name, tz->ntrips,
+						    mask, tz,
+						    ops, tzp,
+						    tz->passive_delay,
+						    tz->polling_delay);
+		if (IS_ERR(zone)) {
+			pr_err("Failed to build %s zone %ld\n", child->name,
+			       PTR_ERR(zone));
+			kfree(tzp);
+			kfree(ops);
+			of_thermal_free_zone(tz);
+			/* attempting to build remaining zones still */
+		}
+	}
+	of_node_put(np);
+
+	return 0;
+
+exit_free:
+	of_node_put(child);
+	of_node_put(np);
+	of_thermal_free_zone(tz);
+
+	/* no memory available, so free what we have built */
+	of_thermal_destroy_zones();
+
+	return -ENOMEM;
+}
+
+/**
+ * of_thermal_destroy_zones - remove all zones parsed and allocated resources
+ *
+ * Finds all zones parsed and added to the thermal framework and remove them
+ * from the system, together with their resources.
+ *
+ */
+void of_thermal_destroy_zones(void)
+{
+	struct device_node *np, *child;
+
+	np = of_find_node_by_name(NULL, "thermal-zones");
+	if (!np) {
+		pr_debug("unable to find thermal zones\n");
+		return;
+	}
+
+	for_each_available_child_of_node(np, child) {
+		struct thermal_zone_device *zone;
+
+		zone = thermal_zone_get_zone_by_name(child->name);
+		if (IS_ERR(zone))
+			continue;
+
+		thermal_zone_device_unregister(zone);
+		kfree(zone->tzp);
+		kfree(zone->ops);
+		of_thermal_free_zone(zone->devdata);
+	}
+	of_node_put(np);
+}