linux/drivers/thermal/thermal_of.c

// 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>
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/err.h>
#include <linux/export.h>
#include <linux/of.h>
#include <linux/slab.h>
#include <linux/thermal.h>
#include <linux/types.h>
#include <linux/string.h>

#include "thermal_core.h"

/***   functions parsing device tree nodes   ***/

/*
 * 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;
}

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;
	}

	trip->flags = THERMAL_TRIP_FLAG_RW_TEMP;

	trip->priv = np;

	return 0;
}

static struct thermal_trip *thermal_of_trips_init(struct device_node *np, int *ntrips)
{
	int ret, count;

	*ntrips = 0;
	
	struct device_node *trips __free(device_node) = of_get_child_by_name(np, "trips");
	if (!trips)
		return NULL;

	count = of_get_child_count(trips);
	if (!count)
		return NULL;

	struct thermal_trip *tt __free(kfree) = kzalloc(sizeof(*tt) * count, GFP_KERNEL);
	if (!tt)
		return ERR_PTR(-ENOMEM);

	count = 0;
	for_each_child_of_node_scoped(trips, trip) {
		ret = thermal_of_populate_trip(trip, &tt[count++]);
		if (ret)
			return ERR_PTR(ret);
	}

	*ntrips = count;

	return no_free_ptr(tt);
}

static struct device_node *of_thermal_zone_find(struct device_node *sensor, int id)
{
	struct of_phandle_args sensor_specs;

	struct device_node *np __free(device_node) = of_find_node_by_name(NULL, "thermal-zones");
	if (!np) {
		pr_debug("No thermal zones description\n");
		return ERR_PTR(-ENODEV);
	}

	/*
	 * Search for each thermal zone, a defined sensor
	 * corresponding to the one passed as parameter
	 */
	for_each_available_child_of_node_scoped(np, child) {

		int count, i;

		count = of_count_phandle_with_args(child, "thermal-sensors",
						   "#thermal-sensor-cells");
		if (count <= 0) {
			pr_err("%pOFn: missing thermal sensor\n", child);
			return ERR_PTR(-EINVAL);
		}

		for (i = 0; i < count; i++) {

			int ret;

			ret = of_parse_phandle_with_args(child, "thermal-sensors",
							 "#thermal-sensor-cells",
							 i, &sensor_specs);
			if (ret < 0) {
				pr_err("%pOFn: Failed to read thermal-sensors cells: %d\n", child, ret);
				return ERR_PTR(ret);
			}

			if ((sensor == sensor_specs.np) && id == (sensor_specs.args_count ?
								  sensor_specs.args[0] : 0)) {
				pr_debug("sensor %pOFn id=%d belongs to %pOFn\n", sensor, id, child);
				return no_free_ptr(child);
			}
		}
	}

	return ERR_PTR(-ENODEV);
}

static int thermal_of_monitor_init(struct device_node *np, int *delay, int *pdelay)
{
	int ret;

	ret = of_property_read_u32(np, "polling-delay-passive", pdelay);
	if (ret == -EINVAL) {
		*pdelay = 0;
	} else if (ret < 0) {
		pr_err("%pOFn: Couldn't get polling-delay-passive: %d\n", np, ret);
		return ret;
	}

	ret = of_property_read_u32(np, "polling-delay", delay);
	if (ret == -EINVAL) {
		*delay = 0;
	} else if (ret < 0) {
		pr_err("%pOFn: Couldn't get polling-delay: %d\n", np, ret);
		return ret;
	}

	return 0;
}

static void thermal_of_parameters_init(struct device_node *np,
				       struct thermal_zone_params *tzp)
{
	int coef[2];
	int ncoef = ARRAY_SIZE(coef);
	int prop, ret;

	tzp->no_hwmon = true;

	if (!of_property_read_u32(np, "sustainable-power", &prop))
		tzp->sustainable_power = prop;

	/*
	 * 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, ncoef);
	if (ret) {
		coef[0] = 1;
		coef[1] = 0;
	}

	tzp->slope = coef[0];
	tzp->offset = coef[1];
}

static struct device_node *thermal_of_zone_get_by_name(struct thermal_zone_device *tz)
{
	struct device_node *np, *tz_np;

	np = of_find_node_by_name(NULL, "thermal-zones");
	if (!np)
		return ERR_PTR(-ENODEV);

	tz_np = of_get_child_by_name(np, tz->type);

	of_node_put(np);

	if (!tz_np)
		return ERR_PTR(-ENODEV);

	return tz_np;
}

static bool thermal_of_get_cooling_spec(struct device_node *map_np, int index,
					struct thermal_cooling_device *cdev,
					struct cooling_spec *c)
{
	struct of_phandle_args cooling_spec;
	int ret, weight = THERMAL_WEIGHT_DEFAULT;

	of_property_read_u32(map_np, "contribution", &weight);

	ret = of_parse_phandle_with_args(map_np, "cooling-device", "#cooling-cells",
					 index, &cooling_spec);

	if (ret < 0) {
		pr_err("Invalid cooling-device entry\n");
		return false;
	}

	of_node_put(cooling_spec.np);

	if (cooling_spec.args_count < 2) {
		pr_err("wrong reference to cooling device, missing limits\n");
		return false;
	}

	if (cooling_spec.np != cdev->np)
		return false;

	c->lower = cooling_spec.args[0];
	c->upper = cooling_spec.args[1];
	c->weight = weight;

	return true;
}

static bool thermal_of_should_bind(struct thermal_zone_device *tz,
				   const struct thermal_trip *trip,
				   struct thermal_cooling_device *cdev,
				   struct cooling_spec *c)
{
	struct device_node *tz_np, *cm_np;
	bool result = false;

	tz_np = thermal_of_zone_get_by_name(tz);
	if (IS_ERR(tz_np)) {
		pr_err("Failed to get node tz by name\n");
		return false;
	}

	cm_np = of_get_child_by_name(tz_np, "cooling-maps");
	if (!cm_np)
		goto out;

	/* Look up the trip and the cdev in the cooling maps. */
	for_each_child_of_node_scoped(cm_np, child) {
		struct device_node *tr_np;
		int count, i;

		tr_np = of_parse_phandle(child, "trip", 0);
		if (tr_np != trip->priv)
			continue;

		/* The trip has been found, look up the cdev. */
		count = of_count_phandle_with_args(child, "cooling-device", "#cooling-cells");
		if (count <= 0)
			pr_err("Add a cooling_device property with at least one device\n");

		for (i = 0; i < count; i++) {
			result = thermal_of_get_cooling_spec(child, i, cdev, c);
			if (result)
				break;
		}

		break;
	}

	of_node_put(cm_np);
out:
	of_node_put(tz_np);

	return result;
}

/**
 * thermal_of_zone_unregister - Cleanup the specific allocated ressources
 *
 * This function disables the thermal zone and frees the different
 * ressources allocated specific to the thermal OF.
 *
 * @tz: a pointer to the thermal zone structure
 */
static void thermal_of_zone_unregister(struct thermal_zone_device *tz)
{
	thermal_zone_device_disable(tz);
	thermal_zone_device_unregister(tz);
}

/**
 * thermal_of_zone_register - Register a thermal zone with device node
 * sensor
 *
 * The thermal_of_zone_register() parses a device tree given a device
 * node sensor and identifier. It searches for the thermal zone
 * associated to the couple sensor/id and retrieves all the thermal
 * zone properties and registers new thermal zone with those
 * properties.
 *
 * @sensor: A device node pointer corresponding to the sensor in the device tree
 * @id: An integer as sensor identifier
 * @data: A private data to be stored in the thermal zone dedicated private area
 * @ops: A set of thermal sensor ops
 *
 * Return: a valid thermal zone structure pointer on success.
 *	- EINVAL: if the device tree thermal description is malformed
 *	- ENOMEM: if one structure can not be allocated
 *	- Other negative errors are returned by the underlying called functions
 */
static struct thermal_zone_device *thermal_of_zone_register(struct device_node *sensor, int id, void *data,
							    const struct thermal_zone_device_ops *ops)
{
	struct thermal_zone_device_ops of_ops = *ops;
	struct thermal_zone_device *tz;
	struct thermal_trip *trips;
	struct thermal_zone_params tzp = {};
	struct device_node *np;
	const char *action;
	int delay, pdelay;
	int ntrips;
	int ret;

	np = of_thermal_zone_find(sensor, id);
	if (IS_ERR(np)) {
		if (PTR_ERR(np) != -ENODEV)
			pr_err("Failed to find thermal zone for %pOFn id=%d\n", sensor, id);
		return ERR_CAST(np);
	}

	trips = thermal_of_trips_init(np, &ntrips);
	if (IS_ERR(trips)) {
		pr_err("Failed to parse trip points for %pOFn id=%d\n", sensor, id);
		ret = PTR_ERR(trips);
		goto out_of_node_put;
	}

	if (!trips)
		pr_info("No trip points found for %pOFn id=%d\n", sensor, id);

	ret = thermal_of_monitor_init(np, &delay, &pdelay);
	if (ret) {
		pr_err("Failed to initialize monitoring delays from %pOFn\n", np);
		goto out_kfree_trips;
	}

	thermal_of_parameters_init(np, &tzp);

	of_ops.should_bind = thermal_of_should_bind;

	ret = of_property_read_string(np, "critical-action", &action);
	if (!ret)
		if (!of_ops.critical && !strcasecmp(action, "reboot"))
			of_ops.critical = thermal_zone_device_critical_reboot;

	tz = thermal_zone_device_register_with_trips(np->name, trips, ntrips,
						     data, &of_ops, &tzp,
						     pdelay, delay);
	if (IS_ERR(tz)) {
		ret = PTR_ERR(tz);
		pr_err("Failed to register thermal zone %pOFn: %d\n", np, ret);
		goto out_kfree_trips;
	}

	of_node_put(np);
	kfree(trips);

	ret = thermal_zone_device_enable(tz);
	if (ret) {
		pr_err("Failed to enabled thermal zone '%s', id=%d: %d\n",
		       tz->type, tz->id, ret);
		thermal_of_zone_unregister(tz);
		return ERR_PTR(ret);
	}

	return tz;

out_kfree_trips:
	kfree(trips);
out_of_node_put:
	of_node_put(np);

	return ERR_PTR(ret);
}

static void devm_thermal_of_zone_release(struct device *dev, void *res)
{
	thermal_of_zone_unregister(*(struct thermal_zone_device **)res);
}

static int devm_thermal_of_zone_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_of_zone_register - register a thermal tied with the sensor life cycle
 *
 * This function is the device version of the thermal_of_zone_register() function.
 *
 * @dev: a device structure pointer to sensor to be tied with the thermal zone OF life cycle
 * @sensor_id: the sensor identifier
 * @data: a pointer to a private data to be stored in the thermal zone 'devdata' field
 * @ops: a pointer to the ops structure associated with the sensor
 */
struct thermal_zone_device *devm_thermal_of_zone_register(struct device *dev, int sensor_id, void *data,
							  const struct thermal_zone_device_ops *ops)
{
	struct thermal_zone_device **ptr, *tzd;

	ptr = devres_alloc(devm_thermal_of_zone_release, sizeof(*ptr),
			   GFP_KERNEL);
	if (!ptr)
		return ERR_PTR(-ENOMEM);

	tzd = thermal_of_zone_register(dev->of_node, 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_of_zone_register);

/**
 * devm_thermal_of_zone_unregister - Resource managed version of
 *				thermal_of_zone_unregister().
 * @dev: Device for which which resource was allocated.
 * @tz: a pointer to struct thermal_zone 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_of_zone_unregister(struct device *dev, struct thermal_zone_device *tz)
{
	WARN_ON(devres_release(dev, devm_thermal_of_zone_release,
			       devm_thermal_of_zone_match, tz));
}
EXPORT_SYMBOL_GPL(devm_thermal_of_zone_unregister);