treewide: remove redundant IS_ERR() before error code check

[linux/fpc-iii.git] / drivers / thermal / thermal_core.c

// SPDX-License-Identifier: GPL-2.0
/*
 *  thermal.c - Generic Thermal Management Sysfs support.
 *
 *  Copyright (C) 2008 Intel Corp
 *  Copyright (C) 2008 Zhang Rui <rui.zhang@intel.com>
 *  Copyright (C) 2008 Sujith Thomas <sujith.thomas@intel.com>
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/kdev_t.h>
#include <linux/idr.h>
#include <linux/thermal.h>
#include <linux/reboot.h>
#include <linux/string.h>
#include <linux/of.h>
#include <linux/suspend.h>

#define CREATE_TRACE_POINTS
#include <trace/events/thermal.h>

#include "thermal_core.h"
#include "thermal_hwmon.h"

MODULE_AUTHOR("Zhang Rui");
MODULE_DESCRIPTION("Generic thermal management sysfs support");
MODULE_LICENSE("GPL v2");

static DEFINE_IDA(thermal_tz_ida);
static DEFINE_IDA(thermal_cdev_ida);

static LIST_HEAD(thermal_tz_list);
static LIST_HEAD(thermal_cdev_list);
static LIST_HEAD(thermal_governor_list);

static DEFINE_MUTEX(thermal_list_lock);
static DEFINE_MUTEX(thermal_governor_lock);
static DEFINE_MUTEX(poweroff_lock);

static atomic_t in_suspend;
static bool power_off_triggered;

static struct thermal_governor *def_governor;

/*
 * Governor section: set of functions to handle thermal governors
 *
 * Functions to help in the life cycle of thermal governors within
 * the thermal core and by the thermal governor code.
 */

static struct thermal_governor *__find_governor(const char *name)
{
        struct thermal_governor *pos;

        if (!name || !name[0])
                return def_governor;

        list_for_each_entry(pos, &thermal_governor_list, governor_list)
                if (!strncasecmp(name, pos->name, THERMAL_NAME_LENGTH))
                        return pos;

        return NULL;
}

/**
 * bind_previous_governor() - bind the previous governor of the thermal zone
 * @tz:         a valid pointer to a struct thermal_zone_device
 * @failed_gov_name:    the name of the governor that failed to register
 *
 * Register the previous governor of the thermal zone after a new
 * governor has failed to be bound.
 */
static void bind_previous_governor(struct thermal_zone_device *tz,
                                   const char *failed_gov_name)
{
        if (tz->governor && tz->governor->bind_to_tz) {
                if (tz->governor->bind_to_tz(tz)) {
                        dev_err(&tz->device,
                                "governor %s failed to bind and the previous one (%s) failed to bind again, thermal zone %s has no governor\n",
                                failed_gov_name, tz->governor->name, tz->type);
                        tz->governor = NULL;
                }
        }
}

/**
 * thermal_set_governor() - Switch to another governor
 * @tz:         a valid pointer to a struct thermal_zone_device
 * @new_gov:    pointer to the new governor
 *
 * Change the governor of thermal zone @tz.
 *
 * Return: 0 on success, an error if the new governor's bind_to_tz() failed.
 */
static int thermal_set_governor(struct thermal_zone_device *tz,
                                struct thermal_governor *new_gov)
{
        int ret = 0;

        if (tz->governor && tz->governor->unbind_from_tz)
                tz->governor->unbind_from_tz(tz);

        if (new_gov && new_gov->bind_to_tz) {
                ret = new_gov->bind_to_tz(tz);
                if (ret) {
                        bind_previous_governor(tz, new_gov->name);

                        return ret;
                }
        }

        tz->governor = new_gov;

        return ret;
}

int thermal_register_governor(struct thermal_governor *governor)
{
        int err;
        const char *name;
        struct thermal_zone_device *pos;

        if (!governor)
                return -EINVAL;

        mutex_lock(&thermal_governor_lock);

        err = -EBUSY;
        if (!__find_governor(governor->name)) {
                bool match_default;

                err = 0;
                list_add(&governor->governor_list, &thermal_governor_list);
                match_default = !strncmp(governor->name,
                                         DEFAULT_THERMAL_GOVERNOR,
                                         THERMAL_NAME_LENGTH);

                if (!def_governor && match_default)
                        def_governor = governor;
        }

        mutex_lock(&thermal_list_lock);

        list_for_each_entry(pos, &thermal_tz_list, node) {
                /*
                 * only thermal zones with specified tz->tzp->governor_name
                 * may run with tz->govenor unset
                 */
                if (pos->governor)
                        continue;

                name = pos->tzp->governor_name;

                if (!strncasecmp(name, governor->name, THERMAL_NAME_LENGTH)) {
                        int ret;

                        ret = thermal_set_governor(pos, governor);
                        if (ret)
                                dev_err(&pos->device,
                                        "Failed to set governor %s for thermal zone %s: %d\n",
                                        governor->name, pos->type, ret);
                }
        }

        mutex_unlock(&thermal_list_lock);
        mutex_unlock(&thermal_governor_lock);

        return err;
}

void thermal_unregister_governor(struct thermal_governor *governor)
{
        struct thermal_zone_device *pos;

        if (!governor)
                return;

        mutex_lock(&thermal_governor_lock);

        if (!__find_governor(governor->name))
                goto exit;

        mutex_lock(&thermal_list_lock);

        list_for_each_entry(pos, &thermal_tz_list, node) {
                if (!strncasecmp(pos->governor->name, governor->name,
                                 THERMAL_NAME_LENGTH))
                        thermal_set_governor(pos, NULL);
        }

        mutex_unlock(&thermal_list_lock);
        list_del(&governor->governor_list);
exit:
        mutex_unlock(&thermal_governor_lock);
}

int thermal_zone_device_set_policy(struct thermal_zone_device *tz,
                                   char *policy)
{
        struct thermal_governor *gov;
        int ret = -EINVAL;

        mutex_lock(&thermal_governor_lock);
        mutex_lock(&tz->lock);

        gov = __find_governor(strim(policy));
        if (!gov)
                goto exit;

        ret = thermal_set_governor(tz, gov);

exit:
        mutex_unlock(&tz->lock);
        mutex_unlock(&thermal_governor_lock);

        return ret;
}

int thermal_build_list_of_policies(char *buf)
{
        struct thermal_governor *pos;
        ssize_t count = 0;
        ssize_t size = PAGE_SIZE;

        mutex_lock(&thermal_governor_lock);

        list_for_each_entry(pos, &thermal_governor_list, governor_list) {
                size = PAGE_SIZE - count;
                count += scnprintf(buf + count, size, "%s ", pos->name);
        }
        count += scnprintf(buf + count, size, "\n");

        mutex_unlock(&thermal_governor_lock);

        return count;
}

static void __init thermal_unregister_governors(void)
{
        struct thermal_governor **governor;

        for_each_governor_table(governor)
                thermal_unregister_governor(*governor);
}

static int __init thermal_register_governors(void)
{
        int ret = 0;
        struct thermal_governor **governor;

        for_each_governor_table(governor) {
                ret = thermal_register_governor(*governor);
                if (ret) {
                        pr_err("Failed to register governor: '%s'",
                               (*governor)->name);
                        break;
                }

                pr_info("Registered thermal governor '%s'",
                        (*governor)->name);
        }

        if (ret) {
                struct thermal_governor **gov;

                for_each_governor_table(gov) {
                        if (gov == governor)
                                break;
                        thermal_unregister_governor(*gov);
                }
        }

        return ret;
}

/*
 * Zone update section: main control loop applied to each zone while monitoring
 *
 * in polling mode. The monitoring is done using a workqueue.
 * Same update may be done on a zone by calling thermal_zone_device_update().
 *
 * An update means:
 * - Non-critical trips will invoke the governor responsible for that zone;
 * - Hot trips will produce a notification to userspace;
 * - Critical trip point will cause a system shutdown.
 */
static void thermal_zone_device_set_polling(struct thermal_zone_device *tz,
                                            int delay)
{
        if (delay > 1000)
                mod_delayed_work(system_freezable_power_efficient_wq,
                                 &tz->poll_queue,
                                 round_jiffies(msecs_to_jiffies(delay)));
        else if (delay)
                mod_delayed_work(system_freezable_power_efficient_wq,
                                 &tz->poll_queue,
                                 msecs_to_jiffies(delay));
        else
                cancel_delayed_work(&tz->poll_queue);
}

static void monitor_thermal_zone(struct thermal_zone_device *tz)
{
        mutex_lock(&tz->lock);

        if (tz->passive)
                thermal_zone_device_set_polling(tz, tz->passive_delay);
        else if (tz->polling_delay)
                thermal_zone_device_set_polling(tz, tz->polling_delay);
        else
                thermal_zone_device_set_polling(tz, 0);

        mutex_unlock(&tz->lock);
}

static void handle_non_critical_trips(struct thermal_zone_device *tz, int trip)
{
        tz->governor ? tz->governor->throttle(tz, trip) :
                       def_governor->throttle(tz, trip);
}

/**
 * thermal_emergency_poweroff_func - emergency poweroff work after a known delay
 * @work: work_struct associated with the emergency poweroff function
 *
 * This function is called in very critical situations to force
 * a kernel poweroff after a configurable timeout value.
 */
static void thermal_emergency_poweroff_func(struct work_struct *work)
{
        /*
         * We have reached here after the emergency thermal shutdown
         * Waiting period has expired. This means orderly_poweroff has
         * not been able to shut off the system for some reason.
         * Try to shut down the system immediately using kernel_power_off
         * if populated
         */
        WARN(1, "Attempting kernel_power_off: Temperature too high\n");
        kernel_power_off();

        /*
         * Worst of the worst case trigger emergency restart
         */
        WARN(1, "Attempting emergency_restart: Temperature too high\n");
        emergency_restart();
}

static DECLARE_DELAYED_WORK(thermal_emergency_poweroff_work,
                            thermal_emergency_poweroff_func);

/**
 * thermal_emergency_poweroff - Trigger an emergency system poweroff
 *
 * This may be called from any critical situation to trigger a system shutdown
 * after a known period of time. By default this is not scheduled.
 */
static void thermal_emergency_poweroff(void)
{
        int poweroff_delay_ms = CONFIG_THERMAL_EMERGENCY_POWEROFF_DELAY_MS;
        /*
         * poweroff_delay_ms must be a carefully profiled positive value.
         * Its a must for thermal_emergency_poweroff_work to be scheduled
         */
        if (poweroff_delay_ms <= 0)
                return;
        schedule_delayed_work(&thermal_emergency_poweroff_work,
                              msecs_to_jiffies(poweroff_delay_ms));
}

static void handle_critical_trips(struct thermal_zone_device *tz,
                                  int trip, enum thermal_trip_type trip_type)
{
        int trip_temp;

        tz->ops->get_trip_temp(tz, trip, &trip_temp);

        /* If we have not crossed the trip_temp, we do not care. */
        if (trip_temp <= 0 || tz->temperature < trip_temp)
                return;

        trace_thermal_zone_trip(tz, trip, trip_type);

        if (tz->ops->notify)
                tz->ops->notify(tz, trip, trip_type);

        if (trip_type == THERMAL_TRIP_CRITICAL) {
                dev_emerg(&tz->device,
                          "critical temperature reached (%d C), shutting down\n",
                          tz->temperature / 1000);
                mutex_lock(&poweroff_lock);
                if (!power_off_triggered) {
                        /*
                         * Queue a backup emergency shutdown in the event of
                         * orderly_poweroff failure
                         */
                        thermal_emergency_poweroff();
                        orderly_poweroff(true);
                        power_off_triggered = true;
                }
                mutex_unlock(&poweroff_lock);
        }
}

static void handle_thermal_trip(struct thermal_zone_device *tz, int trip)
{
        enum thermal_trip_type type;

        /* Ignore disabled trip points */
        if (test_bit(trip, &tz->trips_disabled))
                return;

        tz->ops->get_trip_type(tz, trip, &type);

        if (type == THERMAL_TRIP_CRITICAL || type == THERMAL_TRIP_HOT)
                handle_critical_trips(tz, trip, type);
        else
                handle_non_critical_trips(tz, trip);
        /*
         * Alright, we handled this trip successfully.
         * So, start monitoring again.
         */
        monitor_thermal_zone(tz);
}

static void update_temperature(struct thermal_zone_device *tz)
{
        int temp, ret;

        ret = thermal_zone_get_temp(tz, &temp);
        if (ret) {
                if (ret != -EAGAIN)
                        dev_warn(&tz->device,
                                 "failed to read out thermal zone (%d)\n",
                                 ret);
                return;
        }

        mutex_lock(&tz->lock);
        tz->last_temperature = tz->temperature;
        tz->temperature = temp;
        mutex_unlock(&tz->lock);

        trace_thermal_temperature(tz);
        if (tz->last_temperature == THERMAL_TEMP_INVALID)
                dev_dbg(&tz->device, "last_temperature N/A, current_temperature=%d\n",
                        tz->temperature);
        else
                dev_dbg(&tz->device, "last_temperature=%d, current_temperature=%d\n",
                        tz->last_temperature, tz->temperature);
}

static void thermal_zone_device_init(struct thermal_zone_device *tz)
{
        struct thermal_instance *pos;
        tz->temperature = THERMAL_TEMP_INVALID;
        list_for_each_entry(pos, &tz->thermal_instances, tz_node)
                pos->initialized = false;
}

static void thermal_zone_device_reset(struct thermal_zone_device *tz)
{
        tz->passive = 0;
        thermal_zone_device_init(tz);
}

void thermal_zone_device_update(struct thermal_zone_device *tz,
                                enum thermal_notify_event event)
{
        int count;

        if (atomic_read(&in_suspend))
                return;

        if (!tz->ops->get_temp)
                return;

        update_temperature(tz);

        thermal_zone_set_trips(tz);

        tz->notify_event = event;

        for (count = 0; count < tz->trips; count++)
                handle_thermal_trip(tz, count);
}
EXPORT_SYMBOL_GPL(thermal_zone_device_update);

/**
 * thermal_notify_framework - Sensor drivers use this API to notify framework
 * @tz:         thermal zone device
 * @trip:       indicates which trip point has been crossed
 *
 * This function handles the trip events from sensor drivers. It starts
 * throttling the cooling devices according to the policy configured.
 * For CRITICAL and HOT trip points, this notifies the respective drivers,
 * and does actual throttling for other trip points i.e ACTIVE and PASSIVE.
 * The throttling policy is based on the configured platform data; if no
 * platform data is provided, this uses the step_wise throttling policy.
 */
void thermal_notify_framework(struct thermal_zone_device *tz, int trip)
{
        handle_thermal_trip(tz, trip);
}
EXPORT_SYMBOL_GPL(thermal_notify_framework);

static void thermal_zone_device_check(struct work_struct *work)
{
        struct thermal_zone_device *tz = container_of(work, struct
                                                      thermal_zone_device,
                                                      poll_queue.work);
        thermal_zone_device_update(tz, THERMAL_EVENT_UNSPECIFIED);
}

/*
 * Power actor section: interface to power actors to estimate power
 *
 * Set of functions used to interact to cooling devices that know
 * how to estimate their devices power consumption.
 */

/**
 * power_actor_get_max_power() - get the maximum power that a cdev can consume
 * @cdev:       pointer to &thermal_cooling_device
 * @tz:         a valid thermal zone device pointer
 * @max_power:  pointer in which to store the maximum power
 *
 * Calculate the maximum power consumption in milliwats that the
 * cooling device can currently consume and store it in @max_power.
 *
 * Return: 0 on success, -EINVAL if @cdev doesn't support the
 * power_actor API or -E* on other error.
 */
int power_actor_get_max_power(struct thermal_cooling_device *cdev,
                              struct thermal_zone_device *tz, u32 *max_power)
{
        if (!cdev_is_power_actor(cdev))
                return -EINVAL;

        return cdev->ops->state2power(cdev, tz, 0, max_power);
}

/**
 * power_actor_get_min_power() - get the mainimum power that a cdev can consume
 * @cdev:       pointer to &thermal_cooling_device
 * @tz:         a valid thermal zone device pointer
 * @min_power:  pointer in which to store the minimum power
 *
 * Calculate the minimum power consumption in milliwatts that the
 * cooling device can currently consume and store it in @min_power.
 *
 * Return: 0 on success, -EINVAL if @cdev doesn't support the
 * power_actor API or -E* on other error.
 */
int power_actor_get_min_power(struct thermal_cooling_device *cdev,
                              struct thermal_zone_device *tz, u32 *min_power)
{
        unsigned long max_state;
        int ret;

        if (!cdev_is_power_actor(cdev))
                return -EINVAL;

        ret = cdev->ops->get_max_state(cdev, &max_state);
        if (ret)
                return ret;

        return cdev->ops->state2power(cdev, tz, max_state, min_power);
}

/**
 * power_actor_set_power() - limit the maximum power a cooling device consumes
 * @cdev:       pointer to &thermal_cooling_device
 * @instance:   thermal instance to update
 * @power:      the power in milliwatts
 *
 * Set the cooling device to consume at most @power milliwatts. The limit is
 * expected to be a cap at the maximum power consumption.
 *
 * Return: 0 on success, -EINVAL if the cooling device does not
 * implement the power actor API or -E* for other failures.
 */
int power_actor_set_power(struct thermal_cooling_device *cdev,
                          struct thermal_instance *instance, u32 power)
{
        unsigned long state;
        int ret;

        if (!cdev_is_power_actor(cdev))
                return -EINVAL;

        ret = cdev->ops->power2state(cdev, instance->tz, power, &state);
        if (ret)
                return ret;

        instance->target = state;
        mutex_lock(&cdev->lock);
        cdev->updated = false;
        mutex_unlock(&cdev->lock);
        thermal_cdev_update(cdev);

        return 0;
}

void thermal_zone_device_rebind_exception(struct thermal_zone_device *tz,
                                          const char *cdev_type, size_t size)
{
        struct thermal_cooling_device *cdev = NULL;

        mutex_lock(&thermal_list_lock);
        list_for_each_entry(cdev, &thermal_cdev_list, node) {
                /* skip non matching cdevs */
                if (strncmp(cdev_type, cdev->type, size))
                        continue;

                /* re binding the exception matching the type pattern */
                thermal_zone_bind_cooling_device(tz, THERMAL_TRIPS_NONE, cdev,
                                                 THERMAL_NO_LIMIT,
                                                 THERMAL_NO_LIMIT,
                                                 THERMAL_WEIGHT_DEFAULT);
        }
        mutex_unlock(&thermal_list_lock);
}

void thermal_zone_device_unbind_exception(struct thermal_zone_device *tz,
                                          const char *cdev_type, size_t size)
{
        struct thermal_cooling_device *cdev = NULL;

        mutex_lock(&thermal_list_lock);
        list_for_each_entry(cdev, &thermal_cdev_list, node) {
                /* skip non matching cdevs */
                if (strncmp(cdev_type, cdev->type, size))
                        continue;
                /* unbinding the exception matching the type pattern */
                thermal_zone_unbind_cooling_device(tz, THERMAL_TRIPS_NONE,
                                                   cdev);
        }
        mutex_unlock(&thermal_list_lock);
}

/*
 * Device management section: cooling devices, zones devices, and binding
 *
 * Set of functions provided by the thermal core for:
 * - cooling devices lifecycle: registration, unregistration,
 *                              binding, and unbinding.
 * - thermal zone devices lifecycle: registration, unregistration,
 *                                   binding, and unbinding.
 */

/**
 * thermal_zone_bind_cooling_device() - bind a cooling device to a thermal zone
 * @tz:         pointer to struct thermal_zone_device
 * @trip:       indicates which trip point the cooling devices is
 *              associated with in this thermal zone.
 * @cdev:       pointer to struct thermal_cooling_device
 * @upper:      the Maximum cooling state for this trip point.
 *              THERMAL_NO_LIMIT means no upper limit,
 *              and the cooling device can be in max_state.
 * @lower:      the Minimum cooling state can be used for this trip point.
 *              THERMAL_NO_LIMIT means no lower limit,
 *              and the cooling device can be in cooling state 0.
 * @weight:     The weight of the cooling device to be bound to the
 *              thermal zone. Use THERMAL_WEIGHT_DEFAULT for the
 *              default value
 *
 * This interface function bind a thermal cooling device to the certain trip
 * point of a thermal zone device.
 * This function is usually called in the thermal zone device .bind callback.
 *
 * Return: 0 on success, the proper error value otherwise.
 */
int thermal_zone_bind_cooling_device(struct thermal_zone_device *tz,
                                     int trip,
                                     struct thermal_cooling_device *cdev,
                                     unsigned long upper, unsigned long lower,
                                     unsigned int weight)
{
        struct thermal_instance *dev;
        struct thermal_instance *pos;
        struct thermal_zone_device *pos1;
        struct thermal_cooling_device *pos2;
        unsigned long max_state;
        int result, ret;

        if (trip >= tz->trips || (trip < 0 && trip != THERMAL_TRIPS_NONE))
                return -EINVAL;

        list_for_each_entry(pos1, &thermal_tz_list, node) {
                if (pos1 == tz)
                        break;
        }
        list_for_each_entry(pos2, &thermal_cdev_list, node) {
                if (pos2 == cdev)
                        break;
        }

        if (tz != pos1 || cdev != pos2)
                return -EINVAL;

        ret = cdev->ops->get_max_state(cdev, &max_state);
        if (ret)
                return ret;

        /* lower default 0, upper default max_state */
        lower = lower == THERMAL_NO_LIMIT ? 0 : lower;
        upper = upper == THERMAL_NO_LIMIT ? max_state : upper;

        if (lower > upper || upper > max_state)
                return -EINVAL;

        dev = kzalloc(sizeof(*dev), GFP_KERNEL);
        if (!dev)
                return -ENOMEM;
        dev->tz = tz;
        dev->cdev = cdev;
        dev->trip = trip;
        dev->upper = upper;
        dev->lower = lower;
        dev->target = THERMAL_NO_TARGET;
        dev->weight = weight;

        result = ida_simple_get(&tz->ida, 0, 0, GFP_KERNEL);
        if (result < 0)
                goto free_mem;

        dev->id = result;
        sprintf(dev->name, "cdev%d", dev->id);
        result =
            sysfs_create_link(&tz->device.kobj, &cdev->device.kobj, dev->name);
        if (result)
                goto release_ida;

        sprintf(dev->attr_name, "cdev%d_trip_point", dev->id);
        sysfs_attr_init(&dev->attr.attr);
        dev->attr.attr.name = dev->attr_name;
        dev->attr.attr.mode = 0444;
        dev->attr.show = trip_point_show;
        result = device_create_file(&tz->device, &dev->attr);
        if (result)
                goto remove_symbol_link;

        sprintf(dev->weight_attr_name, "cdev%d_weight", dev->id);
        sysfs_attr_init(&dev->weight_attr.attr);
        dev->weight_attr.attr.name = dev->weight_attr_name;
        dev->weight_attr.attr.mode = S_IWUSR | S_IRUGO;
        dev->weight_attr.show = weight_show;
        dev->weight_attr.store = weight_store;
        result = device_create_file(&tz->device, &dev->weight_attr);
        if (result)
                goto remove_trip_file;

        mutex_lock(&tz->lock);
        mutex_lock(&cdev->lock);
        list_for_each_entry(pos, &tz->thermal_instances, tz_node)
                if (pos->tz == tz && pos->trip == trip && pos->cdev == cdev) {
                        result = -EEXIST;
                        break;
                }
        if (!result) {
                list_add_tail(&dev->tz_node, &tz->thermal_instances);
                list_add_tail(&dev->cdev_node, &cdev->thermal_instances);
                atomic_set(&tz->need_update, 1);
        }
        mutex_unlock(&cdev->lock);
        mutex_unlock(&tz->lock);

        if (!result)
                return 0;

        device_remove_file(&tz->device, &dev->weight_attr);
remove_trip_file:
        device_remove_file(&tz->device, &dev->attr);
remove_symbol_link:
        sysfs_remove_link(&tz->device.kobj, dev->name);
release_ida:
        ida_simple_remove(&tz->ida, dev->id);
free_mem:
        kfree(dev);
        return result;
}
EXPORT_SYMBOL_GPL(thermal_zone_bind_cooling_device);

/**
 * thermal_zone_unbind_cooling_device() - unbind a cooling device from a
 *                                        thermal zone.
 * @tz:         pointer to a struct thermal_zone_device.
 * @trip:       indicates which trip point the cooling devices is
 *              associated with in this thermal zone.
 * @cdev:       pointer to a struct thermal_cooling_device.
 *
 * This interface function unbind a thermal cooling device from the certain
 * trip point of a thermal zone device.
 * This function is usually called in the thermal zone device .unbind callback.
 *
 * Return: 0 on success, the proper error value otherwise.
 */
int thermal_zone_unbind_cooling_device(struct thermal_zone_device *tz,
                                       int trip,
                                       struct thermal_cooling_device *cdev)
{
        struct thermal_instance *pos, *next;

        mutex_lock(&tz->lock);
        mutex_lock(&cdev->lock);
        list_for_each_entry_safe(pos, next, &tz->thermal_instances, tz_node) {
                if (pos->tz == tz && pos->trip == trip && pos->cdev == cdev) {
                        list_del(&pos->tz_node);
                        list_del(&pos->cdev_node);
                        mutex_unlock(&cdev->lock);
                        mutex_unlock(&tz->lock);
                        goto unbind;
                }
        }
        mutex_unlock(&cdev->lock);
        mutex_unlock(&tz->lock);

        return -ENODEV;

unbind:
        device_remove_file(&tz->device, &pos->weight_attr);
        device_remove_file(&tz->device, &pos->attr);
        sysfs_remove_link(&tz->device.kobj, pos->name);
        ida_simple_remove(&tz->ida, pos->id);
        kfree(pos);
        return 0;
}
EXPORT_SYMBOL_GPL(thermal_zone_unbind_cooling_device);

static void thermal_release(struct device *dev)
{
        struct thermal_zone_device *tz;
        struct thermal_cooling_device *cdev;

        if (!strncmp(dev_name(dev), "thermal_zone",
                     sizeof("thermal_zone") - 1)) {
                tz = to_thermal_zone(dev);
                thermal_zone_destroy_device_groups(tz);
                kfree(tz);
        } else if (!strncmp(dev_name(dev), "cooling_device",
                            sizeof("cooling_device") - 1)) {
                cdev = to_cooling_device(dev);
                kfree(cdev);
        }
}

static struct class thermal_class = {
        .name = "thermal",
        .dev_release = thermal_release,
};

static inline
void print_bind_err_msg(struct thermal_zone_device *tz,
                        struct thermal_cooling_device *cdev, int ret)
{
        dev_err(&tz->device, "binding zone %s with cdev %s failed:%d\n",
                tz->type, cdev->type, ret);
}

static void __bind(struct thermal_zone_device *tz, int mask,
                   struct thermal_cooling_device *cdev,
                   unsigned long *limits,
                   unsigned int weight)
{
        int i, ret;

        for (i = 0; i < tz->trips; i++) {
                if (mask & (1 << i)) {
                        unsigned long upper, lower;

                        upper = THERMAL_NO_LIMIT;
                        lower = THERMAL_NO_LIMIT;
                        if (limits) {
                                lower = limits[i * 2];
                                upper = limits[i * 2 + 1];
                        }
                        ret = thermal_zone_bind_cooling_device(tz, i, cdev,
                                                               upper, lower,
                                                               weight);
                        if (ret)
                                print_bind_err_msg(tz, cdev, ret);
                }
        }
}

static void bind_cdev(struct thermal_cooling_device *cdev)
{
        int i, ret;
        const struct thermal_zone_params *tzp;
        struct thermal_zone_device *pos = NULL;

        mutex_lock(&thermal_list_lock);

        list_for_each_entry(pos, &thermal_tz_list, node) {
                if (!pos->tzp && !pos->ops->bind)
                        continue;

                if (pos->ops->bind) {
                        ret = pos->ops->bind(pos, cdev);
                        if (ret)
                                print_bind_err_msg(pos, cdev, ret);
                        continue;
                }

                tzp = pos->tzp;
                if (!tzp || !tzp->tbp)
                        continue;

                for (i = 0; i < tzp->num_tbps; i++) {
                        if (tzp->tbp[i].cdev || !tzp->tbp[i].match)
                                continue;
                        if (tzp->tbp[i].match(pos, cdev))
                                continue;
                        tzp->tbp[i].cdev = cdev;
                        __bind(pos, tzp->tbp[i].trip_mask, cdev,
                               tzp->tbp[i].binding_limits,
                               tzp->tbp[i].weight);
                }
        }

        mutex_unlock(&thermal_list_lock);
}

/**
 * __thermal_cooling_device_register() - register a new thermal cooling device
 * @np:         a pointer to a device tree node.
 * @type:       the thermal cooling device type.
 * @devdata:    device private data.
 * @ops:                standard thermal cooling devices callbacks.
 *
 * This interface function adds a new thermal cooling device (fan/processor/...)
 * to /sys/class/thermal/ folder as cooling_device[0-*]. It tries to bind itself
 * to all the thermal zone devices registered at the same time.
 * It also gives the opportunity to link the cooling device to a device tree
 * node, so that it can be bound to a thermal zone created out of device tree.
 *
 * Return: a pointer to the created struct thermal_cooling_device or an
 * ERR_PTR. Caller must check return value with IS_ERR*() helpers.
 */
static struct thermal_cooling_device *
__thermal_cooling_device_register(struct device_node *np,
                                  const char *type, void *devdata,
                                  const struct thermal_cooling_device_ops *ops)
{
        struct thermal_cooling_device *cdev;
        struct thermal_zone_device *pos = NULL;
        int result;

        if (type && strlen(type) >= THERMAL_NAME_LENGTH)
                return ERR_PTR(-EINVAL);

        if (!ops || !ops->get_max_state || !ops->get_cur_state ||
            !ops->set_cur_state)
                return ERR_PTR(-EINVAL);

        cdev = kzalloc(sizeof(*cdev), GFP_KERNEL);
        if (!cdev)
                return ERR_PTR(-ENOMEM);

        result = ida_simple_get(&thermal_cdev_ida, 0, 0, GFP_KERNEL);
        if (result < 0) {
                kfree(cdev);
                return ERR_PTR(result);
        }

        cdev->id = result;
        strlcpy(cdev->type, type ? : "", sizeof(cdev->type));
        mutex_init(&cdev->lock);
        INIT_LIST_HEAD(&cdev->thermal_instances);
        cdev->np = np;
        cdev->ops = ops;
        cdev->updated = false;
        cdev->device.class = &thermal_class;
        cdev->devdata = devdata;
        thermal_cooling_device_setup_sysfs(cdev);
        dev_set_name(&cdev->device, "cooling_device%d", cdev->id);
        result = device_register(&cdev->device);
        if (result) {
                ida_simple_remove(&thermal_cdev_ida, cdev->id);
                put_device(&cdev->device);
                return ERR_PTR(result);
        }

        /* Add 'this' new cdev to the global cdev list */
        mutex_lock(&thermal_list_lock);
        list_add(&cdev->node, &thermal_cdev_list);
        mutex_unlock(&thermal_list_lock);

        /* Update binding information for 'this' new cdev */
        bind_cdev(cdev);

        mutex_lock(&thermal_list_lock);
        list_for_each_entry(pos, &thermal_tz_list, node)
                if (atomic_cmpxchg(&pos->need_update, 1, 0))
                        thermal_zone_device_update(pos,
                                                   THERMAL_EVENT_UNSPECIFIED);
        mutex_unlock(&thermal_list_lock);

        return cdev;
}

/**
 * thermal_cooling_device_register() - register a new thermal cooling device
 * @type:       the thermal cooling device type.
 * @devdata:    device private data.
 * @ops:                standard thermal cooling devices callbacks.
 *
 * This interface function adds a new thermal cooling device (fan/processor/...)
 * to /sys/class/thermal/ folder as cooling_device[0-*]. It tries to bind itself
 * to all the thermal zone devices registered at the same time.
 *
 * Return: a pointer to the created struct thermal_cooling_device or an
 * ERR_PTR. Caller must check return value with IS_ERR*() helpers.
 */
struct thermal_cooling_device *
thermal_cooling_device_register(const char *type, void *devdata,
                                const struct thermal_cooling_device_ops *ops)
{
        return __thermal_cooling_device_register(NULL, type, devdata, ops);
}
EXPORT_SYMBOL_GPL(thermal_cooling_device_register);

/**
 * thermal_of_cooling_device_register() - register an OF thermal cooling device
 * @np:         a pointer to a device tree node.
 * @type:       the thermal cooling device type.
 * @devdata:    device private data.
 * @ops:                standard thermal cooling devices callbacks.
 *
 * This function will register a cooling device with device tree node reference.
 * This interface function adds a new thermal cooling device (fan/processor/...)
 * to /sys/class/thermal/ folder as cooling_device[0-*]. It tries to bind itself
 * to all the thermal zone devices registered at the same time.
 *
 * Return: a pointer to the created struct thermal_cooling_device or an
 * ERR_PTR. Caller must check return value with IS_ERR*() helpers.
 */
struct thermal_cooling_device *
thermal_of_cooling_device_register(struct device_node *np,
                                   const char *type, void *devdata,
                                   const struct thermal_cooling_device_ops *ops)
{
        return __thermal_cooling_device_register(np, type, devdata, ops);
}
EXPORT_SYMBOL_GPL(thermal_of_cooling_device_register);

static void thermal_cooling_device_release(struct device *dev, void *res)
{
        thermal_cooling_device_unregister(
                                *(struct thermal_cooling_device **)res);
}

/**
 * devm_thermal_of_cooling_device_register() - register an OF thermal cooling
 *                                             device
 * @dev:        a valid struct device pointer of a sensor device.
 * @np:         a pointer to a device tree node.
 * @type:       the thermal cooling device type.
 * @devdata:    device private data.
 * @ops:        standard thermal cooling devices callbacks.
 *
 * This function will register a cooling device with device tree node reference.
 * This interface function adds a new thermal cooling device (fan/processor/...)
 * to /sys/class/thermal/ folder as cooling_device[0-*]. It tries to bind itself
 * to all the thermal zone devices registered at the same time.
 *
 * Return: a pointer to the created struct thermal_cooling_device or an
 * ERR_PTR. Caller must check return value with IS_ERR*() helpers.
 */
struct thermal_cooling_device *
devm_thermal_of_cooling_device_register(struct device *dev,
                                struct device_node *np,
                                char *type, void *devdata,
                                const struct thermal_cooling_device_ops *ops)
{
        struct thermal_cooling_device **ptr, *tcd;

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

        tcd = __thermal_cooling_device_register(np, type, devdata, ops);
        if (IS_ERR(tcd)) {
                devres_free(ptr);
                return tcd;
        }

        *ptr = tcd;
        devres_add(dev, ptr);

        return tcd;
}
EXPORT_SYMBOL_GPL(devm_thermal_of_cooling_device_register);

static void __unbind(struct thermal_zone_device *tz, int mask,
                     struct thermal_cooling_device *cdev)
{
        int i;

        for (i = 0; i < tz->trips; i++)
                if (mask & (1 << i))
                        thermal_zone_unbind_cooling_device(tz, i, cdev);
}

/**
 * thermal_cooling_device_unregister - removes a thermal cooling device
 * @cdev:       the thermal cooling device to remove.
 *
 * thermal_cooling_device_unregister() must be called when a registered
 * thermal cooling device is no longer needed.
 */
void thermal_cooling_device_unregister(struct thermal_cooling_device *cdev)
{
        int i;
        const struct thermal_zone_params *tzp;
        struct thermal_zone_device *tz;
        struct thermal_cooling_device *pos = NULL;

        if (!cdev)
                return;

        mutex_lock(&thermal_list_lock);
        list_for_each_entry(pos, &thermal_cdev_list, node)
                if (pos == cdev)
                        break;
        if (pos != cdev) {
                /* thermal cooling device not found */
                mutex_unlock(&thermal_list_lock);
                return;
        }
        list_del(&cdev->node);

        /* Unbind all thermal zones associated with 'this' cdev */
        list_for_each_entry(tz, &thermal_tz_list, node) {
                if (tz->ops->unbind) {
                        tz->ops->unbind(tz, cdev);
                        continue;
                }

                if (!tz->tzp || !tz->tzp->tbp)
                        continue;

                tzp = tz->tzp;
                for (i = 0; i < tzp->num_tbps; i++) {
                        if (tzp->tbp[i].cdev == cdev) {
                                __unbind(tz, tzp->tbp[i].trip_mask, cdev);
                                tzp->tbp[i].cdev = NULL;
                        }
                }
        }

        mutex_unlock(&thermal_list_lock);

        ida_simple_remove(&thermal_cdev_ida, cdev->id);
        device_del(&cdev->device);
        thermal_cooling_device_destroy_sysfs(cdev);
        put_device(&cdev->device);
}
EXPORT_SYMBOL_GPL(thermal_cooling_device_unregister);

static void bind_tz(struct thermal_zone_device *tz)
{
        int i, ret;
        struct thermal_cooling_device *pos = NULL;
        const struct thermal_zone_params *tzp = tz->tzp;

        if (!tzp && !tz->ops->bind)
                return;

        mutex_lock(&thermal_list_lock);

        /* If there is ops->bind, try to use ops->bind */
        if (tz->ops->bind) {
                list_for_each_entry(pos, &thermal_cdev_list, node) {
                        ret = tz->ops->bind(tz, pos);
                        if (ret)
                                print_bind_err_msg(tz, pos, ret);
                }
                goto exit;
        }

        if (!tzp || !tzp->tbp)
                goto exit;

        list_for_each_entry(pos, &thermal_cdev_list, node) {
                for (i = 0; i < tzp->num_tbps; i++) {
                        if (tzp->tbp[i].cdev || !tzp->tbp[i].match)
                                continue;
                        if (tzp->tbp[i].match(tz, pos))
                                continue;
                        tzp->tbp[i].cdev = pos;
                        __bind(tz, tzp->tbp[i].trip_mask, pos,
                               tzp->tbp[i].binding_limits,
                               tzp->tbp[i].weight);
                }
        }
exit:
        mutex_unlock(&thermal_list_lock);
}

/**
 * thermal_zone_device_register() - register a new thermal zone device
 * @type:       the thermal zone device type
 * @trips:      the number of trip points the thermal zone support
 * @mask:       a bit string indicating the writeablility of trip points
 * @devdata:    private device data
 * @ops:        standard thermal zone device callbacks
 * @tzp:        thermal zone platform parameters
 * @passive_delay: number of milliseconds to wait between polls when
 *                 performing passive cooling
 * @polling_delay: number of milliseconds to wait between polls when checking
 *                 whether trip points have been crossed (0 for interrupt
 *                 driven systems)
 *
 * This interface function adds a new thermal zone device (sensor) to
 * /sys/class/thermal folder as thermal_zone[0-*]. It tries to bind all the
 * thermal cooling devices registered at the same time.
 * thermal_zone_device_unregister() must be called when the device is no
 * longer needed. The passive cooling depends on the .get_trend() return value.
 *
 * Return: a pointer to the created struct thermal_zone_device or an
 * in case of error, an ERR_PTR. Caller must check return value with
 * IS_ERR*() helpers.
 */
struct thermal_zone_device *
thermal_zone_device_register(const char *type, int trips, int mask,
                             void *devdata, struct thermal_zone_device_ops *ops,
                             struct thermal_zone_params *tzp, int passive_delay,
                             int polling_delay)
{
        struct thermal_zone_device *tz;
        enum thermal_trip_type trip_type;
        int trip_temp;
        int id;
        int result;
        int count;
        struct thermal_governor *governor;

        if (!type || strlen(type) == 0) {
                pr_err("Error: No thermal zone type defined\n");
                return ERR_PTR(-EINVAL);
        }

        if (type && strlen(type) >= THERMAL_NAME_LENGTH) {
                pr_err("Error: Thermal zone name (%s) too long, should be under %d chars\n",
                       type, THERMAL_NAME_LENGTH);
                return ERR_PTR(-EINVAL);
        }

        if (trips > THERMAL_MAX_TRIPS || trips < 0 || mask >> trips) {
                pr_err("Error: Incorrect number of thermal trips\n");
                return ERR_PTR(-EINVAL);
        }

        if (!ops) {
                pr_err("Error: Thermal zone device ops not defined\n");
                return ERR_PTR(-EINVAL);
        }

        if (trips > 0 && (!ops->get_trip_type || !ops->get_trip_temp))
                return ERR_PTR(-EINVAL);

        tz = kzalloc(sizeof(*tz), GFP_KERNEL);
        if (!tz)
                return ERR_PTR(-ENOMEM);

        INIT_LIST_HEAD(&tz->thermal_instances);
        ida_init(&tz->ida);
        mutex_init(&tz->lock);
        id = ida_simple_get(&thermal_tz_ida, 0, 0, GFP_KERNEL);
        if (id < 0) {
                result = id;
                goto free_tz;
        }

        tz->id = id;
        strlcpy(tz->type, type, sizeof(tz->type));
        tz->ops = ops;
        tz->tzp = tzp;
        tz->device.class = &thermal_class;
        tz->devdata = devdata;
        tz->trips = trips;
        tz->passive_delay = passive_delay;
        tz->polling_delay = polling_delay;

        /* sys I/F */
        /* Add nodes that are always present via .groups */
        result = thermal_zone_create_device_groups(tz, mask);
        if (result)
                goto remove_id;

        /* A new thermal zone needs to be updated anyway. */
        atomic_set(&tz->need_update, 1);

        dev_set_name(&tz->device, "thermal_zone%d", tz->id);
        result = device_register(&tz->device);
        if (result)
                goto release_device;

        for (count = 0; count < trips; count++) {
                if (tz->ops->get_trip_type(tz, count, &trip_type))
                        set_bit(count, &tz->trips_disabled);
                if (tz->ops->get_trip_temp(tz, count, &trip_temp))
                        set_bit(count, &tz->trips_disabled);
                /* Check for bogus trip points */
                if (trip_temp == 0)
                        set_bit(count, &tz->trips_disabled);
        }

        /* Update 'this' zone's governor information */
        mutex_lock(&thermal_governor_lock);

        if (tz->tzp)
                governor = __find_governor(tz->tzp->governor_name);
        else
                governor = def_governor;

        result = thermal_set_governor(tz, governor);
        if (result) {
                mutex_unlock(&thermal_governor_lock);
                goto unregister;
        }

        mutex_unlock(&thermal_governor_lock);

        if (!tz->tzp || !tz->tzp->no_hwmon) {
                result = thermal_add_hwmon_sysfs(tz);
                if (result)
                        goto unregister;
        }

        mutex_lock(&thermal_list_lock);
        list_add_tail(&tz->node, &thermal_tz_list);
        mutex_unlock(&thermal_list_lock);

        /* Bind cooling devices for this zone */
        bind_tz(tz);

        INIT_DELAYED_WORK(&tz->poll_queue, thermal_zone_device_check);

        thermal_zone_device_reset(tz);
        /* Update the new thermal zone and mark it as already updated. */
        if (atomic_cmpxchg(&tz->need_update, 1, 0))
                thermal_zone_device_update(tz, THERMAL_EVENT_UNSPECIFIED);

        return tz;

unregister:
        device_del(&tz->device);
release_device:
        put_device(&tz->device);
        tz = NULL;
remove_id:
        ida_simple_remove(&thermal_tz_ida, id);
free_tz:
        kfree(tz);
        return ERR_PTR(result);
}
EXPORT_SYMBOL_GPL(thermal_zone_device_register);

/**
 * thermal_device_unregister - removes the registered thermal zone device
 * @tz: the thermal zone device to remove
 */
void thermal_zone_device_unregister(struct thermal_zone_device *tz)
{
        int i;
        const struct thermal_zone_params *tzp;
        struct thermal_cooling_device *cdev;
        struct thermal_zone_device *pos = NULL;

        if (!tz)
                return;

        tzp = tz->tzp;

        mutex_lock(&thermal_list_lock);
        list_for_each_entry(pos, &thermal_tz_list, node)
                if (pos == tz)
                        break;
        if (pos != tz) {
                /* thermal zone device not found */
                mutex_unlock(&thermal_list_lock);
                return;
        }
        list_del(&tz->node);

        /* Unbind all cdevs associated with 'this' thermal zone */
        list_for_each_entry(cdev, &thermal_cdev_list, node) {
                if (tz->ops->unbind) {
                        tz->ops->unbind(tz, cdev);
                        continue;
                }

                if (!tzp || !tzp->tbp)
                        break;

                for (i = 0; i < tzp->num_tbps; i++) {
                        if (tzp->tbp[i].cdev == cdev) {
                                __unbind(tz, tzp->tbp[i].trip_mask, cdev);
                                tzp->tbp[i].cdev = NULL;
                        }
                }
        }

        mutex_unlock(&thermal_list_lock);

        cancel_delayed_work_sync(&tz->poll_queue);

        thermal_set_governor(tz, NULL);

        thermal_remove_hwmon_sysfs(tz);
        ida_simple_remove(&thermal_tz_ida, tz->id);
        ida_destroy(&tz->ida);
        mutex_destroy(&tz->lock);
        device_unregister(&tz->device);
}
EXPORT_SYMBOL_GPL(thermal_zone_device_unregister);

/**
 * thermal_zone_get_zone_by_name() - search for a zone and returns its ref
 * @name: thermal zone name to fetch the temperature
 *
 * When only one zone is found with the passed name, returns a reference to it.
 *
 * Return: On success returns a reference to an unique thermal zone with
 * matching name equals to @name, an ERR_PTR otherwise (-EINVAL for invalid
 * paramenters, -ENODEV for not found and -EEXIST for multiple matches).
 */
struct thermal_zone_device *thermal_zone_get_zone_by_name(const char *name)
{
        struct thermal_zone_device *pos = NULL, *ref = ERR_PTR(-EINVAL);
        unsigned int found = 0;

        if (!name)
                goto exit;

        mutex_lock(&thermal_list_lock);
        list_for_each_entry(pos, &thermal_tz_list, node)
                if (!strncasecmp(name, pos->type, THERMAL_NAME_LENGTH)) {
                        found++;
                        ref = pos;
                }
        mutex_unlock(&thermal_list_lock);

        /* nothing has been found, thus an error code for it */
        if (found == 0)
                ref = ERR_PTR(-ENODEV);
        else if (found > 1)
        /* Success only when an unique zone is found */
                ref = ERR_PTR(-EEXIST);

exit:
        return ref;
}
EXPORT_SYMBOL_GPL(thermal_zone_get_zone_by_name);

static int thermal_pm_notify(struct notifier_block *nb,
                             unsigned long mode, void *_unused)
{
        struct thermal_zone_device *tz;
        enum thermal_device_mode tz_mode;

        switch (mode) {
        case PM_HIBERNATION_PREPARE:
        case PM_RESTORE_PREPARE:
        case PM_SUSPEND_PREPARE:
                atomic_set(&in_suspend, 1);
                break;
        case PM_POST_HIBERNATION:
        case PM_POST_RESTORE:
        case PM_POST_SUSPEND:
                atomic_set(&in_suspend, 0);
                list_for_each_entry(tz, &thermal_tz_list, node) {
                        tz_mode = THERMAL_DEVICE_ENABLED;
                        if (tz->ops->get_mode)
                                tz->ops->get_mode(tz, &tz_mode);

                        if (tz_mode == THERMAL_DEVICE_DISABLED)
                                continue;

                        thermal_zone_device_init(tz);
                        thermal_zone_device_update(tz,
                                                   THERMAL_EVENT_UNSPECIFIED);
                }
                break;
        default:
                break;
        }
        return 0;
}

static struct notifier_block thermal_pm_nb = {
        .notifier_call = thermal_pm_notify,
};

static int __init thermal_init(void)
{
        int result;

        mutex_init(&poweroff_lock);
        result = thermal_register_governors();
        if (result)
                goto error;

        result = class_register(&thermal_class);
        if (result)
                goto unregister_governors;

        result = of_parse_thermal_zones();
        if (result)
                goto unregister_class;

        result = register_pm_notifier(&thermal_pm_nb);
        if (result)
                pr_warn("Thermal: Can not register suspend notifier, return %d\n",
                        result);

        return 0;

unregister_class:
        class_unregister(&thermal_class);
unregister_governors:
        thermal_unregister_governors();
error:
        ida_destroy(&thermal_tz_ida);
        ida_destroy(&thermal_cdev_ida);
        mutex_destroy(&thermal_list_lock);
        mutex_destroy(&thermal_governor_lock);
        mutex_destroy(&poweroff_lock);
        return result;
}
core_initcall(thermal_init);