// SPDX-License-Identifier: GPL-2.0
/*
 *  thermal.c - sysfs interface of thermal devices
 *
 *  Copyright (C) 2016 Eduardo Valentin <edubezval@gmail.com>
 *
 *  Highly based on original thermal_core.c
 *  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/sysfs.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/jiffies.h>

#include "thermal_core.h"

/* sys I/F for thermal zone */

static ssize_t
type_show(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct thermal_zone_device *tz = to_thermal_zone(dev);

        return sprintf(buf, "%s\n", tz->type);
}

static ssize_t
temp_show(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct thermal_zone_device *tz = to_thermal_zone(dev);
        int temperature, ret;

        ret = thermal_zone_get_temp(tz, &temperature);

        if (ret)
                return ret;

        return sprintf(buf, "%d\n", temperature);
}

static ssize_t
mode_show(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct thermal_zone_device *tz = to_thermal_zone(dev);
        int enabled = thermal_zone_device_is_enabled(tz);

        return sprintf(buf, "%s\n", enabled ? "enabled" : "disabled");
}

static ssize_t
mode_store(struct device *dev, struct device_attribute *attr,
           const char *buf, size_t count)
{
        struct thermal_zone_device *tz = to_thermal_zone(dev);
        int result;

        if (!strncmp(buf, "enabled", sizeof("enabled") - 1))
                result = thermal_zone_device_enable(tz);
        else if (!strncmp(buf, "disabled", sizeof("disabled") - 1))
                result = thermal_zone_device_disable(tz);
        else
                result = -EINVAL;

        if (result)
                return result;

        return count;
}

static ssize_t
trip_point_type_show(struct device *dev, struct device_attribute *attr,
                     char *buf)
{
        struct thermal_zone_device *tz = to_thermal_zone(dev);
        enum thermal_trip_type type;
        int trip, result;

        if (!tz->ops->get_trip_type)
                return -EPERM;

        if (sscanf(attr->attr.name, "trip_point_%d_type", &trip) != 1)
                return -EINVAL;

        result = tz->ops->get_trip_type(tz, trip, &type);
        if (result)
                return result;

        switch (type) {
        case THERMAL_TRIP_CRITICAL:
                return sprintf(buf, "critical\n");
        case THERMAL_TRIP_HOT:
                return sprintf(buf, "hot\n");
        case THERMAL_TRIP_PASSIVE:
                return sprintf(buf, "passive\n");
        case THERMAL_TRIP_ACTIVE:
                return sprintf(buf, "active\n");
        default:
                return sprintf(buf, "unknown\n");
        }
}

static ssize_t
trip_point_temp_store(struct device *dev, struct device_attribute *attr,
                      const char *buf, size_t count)
{
        struct thermal_zone_device *tz = to_thermal_zone(dev);
        int trip, ret;
        int temperature, hyst = 0;
        enum thermal_trip_type type;

        if (!tz->ops->set_trip_temp)
                return -EPERM;

        if (sscanf(attr->attr.name, "trip_point_%d_temp", &trip) != 1)
                return -EINVAL;

        if (kstrtoint(buf, 10, &temperature))
                return -EINVAL;

        ret = tz->ops->set_trip_temp(tz, trip, temperature);
        if (ret)
                return ret;

        if (tz->ops->get_trip_hyst) {
                ret = tz->ops->get_trip_hyst(tz, trip, &hyst);
                if (ret)
                        return ret;
        }

        ret = tz->ops->get_trip_type(tz, trip, &type);
        if (ret)
                return ret;

        thermal_notify_tz_trip_change(tz->id, trip, type, temperature, hyst);

        thermal_zone_device_update(tz, THERMAL_EVENT_UNSPECIFIED);

        return count;
}

static ssize_t
trip_point_temp_show(struct device *dev, struct device_attribute *attr,
                     char *buf)
{
        struct thermal_zone_device *tz = to_thermal_zone(dev);
        int trip, ret;
        int temperature;

        if (!tz->ops->get_trip_temp)
                return -EPERM;

        if (sscanf(attr->attr.name, "trip_point_%d_temp", &trip) != 1)
                return -EINVAL;

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

        if (ret)
                return ret;

        return sprintf(buf, "%d\n", temperature);
}

static ssize_t
trip_point_hyst_store(struct device *dev, struct device_attribute *attr,
                      const char *buf, size_t count)
{
        struct thermal_zone_device *tz = to_thermal_zone(dev);
        int trip, ret;
        int temperature;

        if (!tz->ops->set_trip_hyst)
                return -EPERM;

        if (sscanf(attr->attr.name, "trip_point_%d_hyst", &trip) != 1)
                return -EINVAL;

        if (kstrtoint(buf, 10, &temperature))
                return -EINVAL;

        /*
         * We are not doing any check on the 'temperature' value
         * here. The driver implementing 'set_trip_hyst' has to
         * take care of this.
         */
        ret = tz->ops->set_trip_hyst(tz, trip, temperature);

        if (!ret)
                thermal_zone_set_trips(tz);

        return ret ? ret : count;
}

static ssize_t
trip_point_hyst_show(struct device *dev, struct device_attribute *attr,
                     char *buf)
{
        struct thermal_zone_device *tz = to_thermal_zone(dev);
        int trip, ret;
        int temperature;

        if (!tz->ops->get_trip_hyst)
                return -EPERM;

        if (sscanf(attr->attr.name, "trip_point_%d_hyst", &trip) != 1)
                return -EINVAL;

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

        return ret ? ret : sprintf(buf, "%d\n", temperature);
}

static ssize_t
policy_store(struct device *dev, struct device_attribute *attr,
             const char *buf, size_t count)
{
        struct thermal_zone_device *tz = to_thermal_zone(dev);
        char name[THERMAL_NAME_LENGTH];
        int ret;

        snprintf(name, sizeof(name), "%s", buf);

        ret = thermal_zone_device_set_policy(tz, name);
        if (!ret)
                ret = count;

        return ret;
}

static ssize_t
policy_show(struct device *dev, struct device_attribute *devattr, char *buf)
{
        struct thermal_zone_device *tz = to_thermal_zone(dev);

        return sprintf(buf, "%s\n", tz->governor->name);
}

static ssize_t
available_policies_show(struct device *dev, struct device_attribute *devattr,
                        char *buf)
{
        return thermal_build_list_of_policies(buf);
}

#if (IS_ENABLED(CONFIG_THERMAL_EMULATION))
static ssize_t
emul_temp_store(struct device *dev, struct device_attribute *attr,
                const char *buf, size_t count)
{
        struct thermal_zone_device *tz = to_thermal_zone(dev);
        int ret = 0;
        int temperature;

        if (kstrtoint(buf, 10, &temperature))
                return -EINVAL;

        if (!tz->ops->set_emul_temp) {
                mutex_lock(&tz->lock);
                tz->emul_temperature = temperature;
                mutex_unlock(&tz->lock);
        } else {
                ret = tz->ops->set_emul_temp(tz, temperature);
        }

        if (!ret)
                thermal_zone_device_update(tz, THERMAL_EVENT_UNSPECIFIED);

        return ret ? ret : count;
}
static DEVICE_ATTR_WO(emul_temp);
#endif

static ssize_t
sustainable_power_show(struct device *dev, struct device_attribute *devattr,
                       char *buf)
{
        struct thermal_zone_device *tz = to_thermal_zone(dev);

        if (tz->tzp)
                return sprintf(buf, "%u\n", tz->tzp->sustainable_power);
        else
                return -EIO;
}

static ssize_t
sustainable_power_store(struct device *dev, struct device_attribute *devattr,
                        const char *buf, size_t count)
{
        struct thermal_zone_device *tz = to_thermal_zone(dev);
        u32 sustainable_power;

        if (!tz->tzp)
                return -EIO;

        if (kstrtou32(buf, 10, &sustainable_power))
                return -EINVAL;

        tz->tzp->sustainable_power = sustainable_power;

        return count;
}

#define create_s32_tzp_attr(name)                                       \
        static ssize_t                                                  \
        name##_show(struct device *dev, struct device_attribute *devattr, \
                char *buf)                                              \
        {                                                               \
        struct thermal_zone_device *tz = to_thermal_zone(dev);          \
                                                                        \
        if (tz->tzp)                                                    \
                return sprintf(buf, "%d\n", tz->tzp->name);             \
        else                                                            \
                return -EIO;                                            \
        }                                                               \
                                                                        \
        static ssize_t                                                  \
        name##_store(struct device *dev, struct device_attribute *devattr, \
                const char *buf, size_t count)                          \
        {                                                               \
                struct thermal_zone_device *tz = to_thermal_zone(dev);  \
                s32 value;                                              \
                                                                        \
                if (!tz->tzp)                                           \
                        return -EIO;                                    \
                                                                        \
                if (kstrtos32(buf, 10, &value))                         \
                        return -EINVAL;                                 \
                                                                        \
                tz->tzp->name = value;                                  \
                                                                        \
                return count;                                           \
        }                                                               \
        static DEVICE_ATTR_RW(name)

create_s32_tzp_attr(k_po);
create_s32_tzp_attr(k_pu);
create_s32_tzp_attr(k_i);
create_s32_tzp_attr(k_d);
create_s32_tzp_attr(integral_cutoff);
create_s32_tzp_attr(slope);
create_s32_tzp_attr(offset);
#undef create_s32_tzp_attr

/*
 * These are thermal zone device attributes that will always be present.
 * All the attributes created for tzp (create_s32_tzp_attr) also are always
 * present on the sysfs interface.
 */
static DEVICE_ATTR_RO(type);
static DEVICE_ATTR_RO(temp);
static DEVICE_ATTR_RW(policy);
static DEVICE_ATTR_RO(available_policies);
static DEVICE_ATTR_RW(sustainable_power);

/* These thermal zone device attributes are created based on conditions */
static DEVICE_ATTR_RW(mode);

/* These attributes are unconditionally added to a thermal zone */
static struct attribute *thermal_zone_dev_attrs[] = {
        &dev_attr_type.attr,
        &dev_attr_temp.attr,
#if (IS_ENABLED(CONFIG_THERMAL_EMULATION))
        &dev_attr_emul_temp.attr,
#endif
        &dev_attr_policy.attr,
        &dev_attr_available_policies.attr,
        &dev_attr_sustainable_power.attr,
        &dev_attr_k_po.attr,
        &dev_attr_k_pu.attr,
        &dev_attr_k_i.attr,
        &dev_attr_k_d.attr,
        &dev_attr_integral_cutoff.attr,
        &dev_attr_slope.attr,
        &dev_attr_offset.attr,
        NULL,
};

static const struct attribute_group thermal_zone_attribute_group = {
        .attrs = thermal_zone_dev_attrs,
};

static struct attribute *thermal_zone_mode_attrs[] = {
        &dev_attr_mode.attr,
        NULL,
};

static const struct attribute_group thermal_zone_mode_attribute_group = {
        .attrs = thermal_zone_mode_attrs,
};

static const struct attribute_group *thermal_zone_attribute_groups[] = {
        &thermal_zone_attribute_group,
        &thermal_zone_mode_attribute_group,
        /* This is not NULL terminated as we create the group dynamically */
};

/**
 * create_trip_attrs() - create attributes for trip points
 * @tz:         the thermal zone device
 * @mask:       Writeable trip point bitmap.
 *
 * helper function to instantiate sysfs entries for every trip
 * point and its properties of a struct thermal_zone_device.
 *
 * Return: 0 on success, the proper error value otherwise.
 */
static int create_trip_attrs(struct thermal_zone_device *tz, int mask)
{
        struct attribute **attrs;
        int indx;

        /* This function works only for zones with at least one trip */
        if (tz->trips <= 0)
                return -EINVAL;

        tz->trip_type_attrs = kcalloc(tz->trips, sizeof(*tz->trip_type_attrs),
                                      GFP_KERNEL);
        if (!tz->trip_type_attrs)
                return -ENOMEM;

        tz->trip_temp_attrs = kcalloc(tz->trips, sizeof(*tz->trip_temp_attrs),
                                      GFP_KERNEL);
        if (!tz->trip_temp_attrs) {
                kfree(tz->trip_type_attrs);
                return -ENOMEM;
        }

        if (tz->ops->get_trip_hyst) {
                tz->trip_hyst_attrs = kcalloc(tz->trips,
                                              sizeof(*tz->trip_hyst_attrs),
                                              GFP_KERNEL);
                if (!tz->trip_hyst_attrs) {
                        kfree(tz->trip_type_attrs);
                        kfree(tz->trip_temp_attrs);
                        return -ENOMEM;
                }
        }

        attrs = kcalloc(tz->trips * 3 + 1, sizeof(*attrs), GFP_KERNEL);
        if (!attrs) {
                kfree(tz->trip_type_attrs);
                kfree(tz->trip_temp_attrs);
                if (tz->ops->get_trip_hyst)
                        kfree(tz->trip_hyst_attrs);
                return -ENOMEM;
        }

        for (indx = 0; indx < tz->trips; indx++) {
                /* create trip type attribute */
                snprintf(tz->trip_type_attrs[indx].name, THERMAL_NAME_LENGTH,
                         "trip_point_%d_type", indx);

                sysfs_attr_init(&tz->trip_type_attrs[indx].attr.attr);
                tz->trip_type_attrs[indx].attr.attr.name =
                                                tz->trip_type_attrs[indx].name;
                tz->trip_type_attrs[indx].attr.attr.mode = S_IRUGO;
                tz->trip_type_attrs[indx].attr.show = trip_point_type_show;
                attrs[indx] = &tz->trip_type_attrs[indx].attr.attr;

                /* create trip temp attribute */
                snprintf(tz->trip_temp_attrs[indx].name, THERMAL_NAME_LENGTH,
                         "trip_point_%d_temp", indx);

                sysfs_attr_init(&tz->trip_temp_attrs[indx].attr.attr);
                tz->trip_temp_attrs[indx].attr.attr.name =
                                                tz->trip_temp_attrs[indx].name;
                tz->trip_temp_attrs[indx].attr.attr.mode = S_IRUGO;
                tz->trip_temp_attrs[indx].attr.show = trip_point_temp_show;
                if (IS_ENABLED(CONFIG_THERMAL_WRITABLE_TRIPS) &&
                    mask & (1 << indx)) {
                        tz->trip_temp_attrs[indx].attr.attr.mode |= S_IWUSR;
                        tz->trip_temp_attrs[indx].attr.store =
                                                        trip_point_temp_store;
                }
                attrs[indx + tz->trips] = &tz->trip_temp_attrs[indx].attr.attr;

                /* create Optional trip hyst attribute */
                if (!tz->ops->get_trip_hyst)
                        continue;
                snprintf(tz->trip_hyst_attrs[indx].name, THERMAL_NAME_LENGTH,
                         "trip_point_%d_hyst", indx);

                sysfs_attr_init(&tz->trip_hyst_attrs[indx].attr.attr);
                tz->trip_hyst_attrs[indx].attr.attr.name =
                                        tz->trip_hyst_attrs[indx].name;
                tz->trip_hyst_attrs[indx].attr.attr.mode = S_IRUGO;
                tz->trip_hyst_attrs[indx].attr.show = trip_point_hyst_show;
                if (tz->ops->set_trip_hyst) {
                        tz->trip_hyst_attrs[indx].attr.attr.mode |= S_IWUSR;
                        tz->trip_hyst_attrs[indx].attr.store =
                                        trip_point_hyst_store;
                }
                attrs[indx + tz->trips * 2] =
                                        &tz->trip_hyst_attrs[indx].attr.attr;
        }
        attrs[tz->trips * 3] = NULL;

        tz->trips_attribute_group.attrs = attrs;

        return 0;
}

/**
 * destroy_trip_attrs() - destroy attributes for trip points
 * @tz:         the thermal zone device
 *
 * helper function to free resources allocated by create_trip_attrs()
 */
static void destroy_trip_attrs(struct thermal_zone_device *tz)
{
        if (!tz)
                return;

        kfree(tz->trip_type_attrs);
        kfree(tz->trip_temp_attrs);
        if (tz->ops->get_trip_hyst)
                kfree(tz->trip_hyst_attrs);
        kfree(tz->trips_attribute_group.attrs);
}

int thermal_zone_create_device_groups(struct thermal_zone_device *tz,
                                      int mask)
{
        const struct attribute_group **groups;
        int i, size, result;

        /* we need one extra for trips and the NULL to terminate the array */
        size = ARRAY_SIZE(thermal_zone_attribute_groups) + 2;
        /* This also takes care of API requirement to be NULL terminated */
        groups = kcalloc(size, sizeof(*groups), GFP_KERNEL);
        if (!groups)
                return -ENOMEM;

        for (i = 0; i < size - 2; i++)
                groups[i] = thermal_zone_attribute_groups[i];

        if (tz->trips) {
                result = create_trip_attrs(tz, mask);
                if (result) {
                        kfree(groups);

                        return result;
                }

                groups[size - 2] = &tz->trips_attribute_group;
        }

        tz->device.groups = groups;

        return 0;
}

void thermal_zone_destroy_device_groups(struct thermal_zone_device *tz)
{
        if (!tz)
                return;

        if (tz->trips)
                destroy_trip_attrs(tz);

        kfree(tz->device.groups);
}

/* sys I/F for cooling device */
static ssize_t
cdev_type_show(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct thermal_cooling_device *cdev = to_cooling_device(dev);

        return sprintf(buf, "%s\n", cdev->type);
}

static ssize_t max_state_show(struct device *dev, struct device_attribute *attr,
                              char *buf)
{
        struct thermal_cooling_device *cdev = to_cooling_device(dev);
        unsigned long state;
        int ret;

        ret = cdev->ops->get_max_state(cdev, &state);
        if (ret)
                return ret;
        return sprintf(buf, "%ld\n", state);
}

static ssize_t cur_state_show(struct device *dev, struct device_attribute *attr,
                              char *buf)
{
        struct thermal_cooling_device *cdev = to_cooling_device(dev);
        unsigned long state;
        int ret;

        ret = cdev->ops->get_cur_state(cdev, &state);
        if (ret)
                return ret;
        return sprintf(buf, "%ld\n", state);
}

static ssize_t
cur_state_store(struct device *dev, struct device_attribute *attr,
                const char *buf, size_t count)
{
        struct thermal_cooling_device *cdev = to_cooling_device(dev);
        unsigned long state;
        int result;

        if (sscanf(buf, "%ld\n", &state) != 1)
                return -EINVAL;

        if ((long)state < 0)
                return -EINVAL;

        mutex_lock(&cdev->lock);

        result = cdev->ops->set_cur_state(cdev, state);
        if (!result)
                thermal_cooling_device_stats_update(cdev, state);

        mutex_unlock(&cdev->lock);
        return result ? result : count;
}

static struct device_attribute
dev_attr_cdev_type = __ATTR(type, 0444, cdev_type_show, NULL);
static DEVICE_ATTR_RO(max_state);
static DEVICE_ATTR_RW(cur_state);

static struct attribute *cooling_device_attrs[] = {
        &dev_attr_cdev_type.attr,
        &dev_attr_max_state.attr,
        &dev_attr_cur_state.attr,
        NULL,
};

static const struct attribute_group cooling_device_attr_group = {
        .attrs = cooling_device_attrs,
};

static const struct attribute_group *cooling_device_attr_groups[] = {
        &cooling_device_attr_group,
        NULL, /* Space allocated for cooling_device_stats_attr_group */
        NULL,
};

#ifdef CONFIG_THERMAL_STATISTICS
struct cooling_dev_stats {
        spinlock_t lock;
        unsigned int total_trans;
        unsigned long state;
        unsigned long max_states;
        ktime_t last_time;
        ktime_t *time_in_state;
        unsigned int *trans_table;
};

static void update_time_in_state(struct cooling_dev_stats *stats)
{
        ktime_t now = ktime_get(), delta;

        delta = ktime_sub(now, stats->last_time);
        stats->time_in_state[stats->state] =
                ktime_add(stats->time_in_state[stats->state], delta);
        stats->last_time = now;
}

void thermal_cooling_device_stats_update(struct thermal_cooling_device *cdev,
                                         unsigned long new_state)
{
        struct cooling_dev_stats *stats = cdev->stats;

        if (!stats)
                return;

        spin_lock(&stats->lock);

        if (stats->state == new_state)
                goto unlock;

        update_time_in_state(stats);
        stats->trans_table[stats->state * stats->max_states + new_state]++;
        stats->state = new_state;
        stats->total_trans++;

unlock:
        spin_unlock(&stats->lock);
}

static ssize_t total_trans_show(struct device *dev,
                                struct device_attribute *attr, char *buf)
{
        struct thermal_cooling_device *cdev = to_cooling_device(dev);
        struct cooling_dev_stats *stats = cdev->stats;
        int ret;

        spin_lock(&stats->lock);
        ret = sprintf(buf, "%u\n", stats->total_trans);
        spin_unlock(&stats->lock);

        return ret;
}

static ssize_t
time_in_state_ms_show(struct device *dev, struct device_attribute *attr,
                      char *buf)
{
        struct thermal_cooling_device *cdev = to_cooling_device(dev);
        struct cooling_dev_stats *stats = cdev->stats;
        ssize_t len = 0;
        int i;

        spin_lock(&stats->lock);
        update_time_in_state(stats);

        for (i = 0; i < stats->max_states; i++) {
                len += sprintf(buf + len, "state%u\t%llu\n", i,
                               ktime_to_ms(stats->time_in_state[i]));
        }
        spin_unlock(&stats->lock);

        return len;
}

static ssize_t
reset_store(struct device *dev, struct device_attribute *attr, const char *buf,
            size_t count)
{
        struct thermal_cooling_device *cdev = to_cooling_device(dev);
        struct cooling_dev_stats *stats = cdev->stats;
        int i, states = stats->max_states;

        spin_lock(&stats->lock);

        stats->total_trans = 0;
        stats->last_time = ktime_get();
        memset(stats->trans_table, 0,
               states * states * sizeof(*stats->trans_table));

        for (i = 0; i < stats->max_states; i++)
                stats->time_in_state[i] = ktime_set(0, 0);

        spin_unlock(&stats->lock);

        return count;
}

static ssize_t trans_table_show(struct device *dev,
                                struct device_attribute *attr, char *buf)
{
        struct thermal_cooling_device *cdev = to_cooling_device(dev);
        struct cooling_dev_stats *stats = cdev->stats;
        ssize_t len = 0;
        int i, j;

        len += snprintf(buf + len, PAGE_SIZE - len, " From  :    To\n");
        len += snprintf(buf + len, PAGE_SIZE - len, "       : ");
        for (i = 0; i < stats->max_states; i++) {
                if (len >= PAGE_SIZE)
                        break;
                len += snprintf(buf + len, PAGE_SIZE - len, "state%2u  ", i);
        }
        if (len >= PAGE_SIZE)
                return PAGE_SIZE;

        len += snprintf(buf + len, PAGE_SIZE - len, "\n");

        for (i = 0; i < stats->max_states; i++) {
                if (len >= PAGE_SIZE)
                        break;

                len += snprintf(buf + len, PAGE_SIZE - len, "state%2u:", i);

                for (j = 0; j < stats->max_states; j++) {
                        if (len >= PAGE_SIZE)
                                break;
                        len += snprintf(buf + len, PAGE_SIZE - len, "%8u ",
                                stats->trans_table[i * stats->max_states + j]);
                }
                if (len >= PAGE_SIZE)
                        break;
                len += snprintf(buf + len, PAGE_SIZE - len, "\n");
        }

        if (len >= PAGE_SIZE) {
                pr_warn_once("Thermal transition table exceeds PAGE_SIZE. Disabling\n");
                return -EFBIG;
        }
        return len;
}

static DEVICE_ATTR_RO(total_trans);
static DEVICE_ATTR_RO(time_in_state_ms);
static DEVICE_ATTR_WO(reset);
static DEVICE_ATTR_RO(trans_table);

static struct attribute *cooling_device_stats_attrs[] = {
        &dev_attr_total_trans.attr,
        &dev_attr_time_in_state_ms.attr,
        &dev_attr_reset.attr,
        &dev_attr_trans_table.attr,
        NULL
};

static const struct attribute_group cooling_device_stats_attr_group = {
        .attrs = cooling_device_stats_attrs,
        .name = "stats"
};

static void cooling_device_stats_setup(struct thermal_cooling_device *cdev)
{
        struct cooling_dev_stats *stats;
        unsigned long states;
        int var;

        if (cdev->ops->get_max_state(cdev, &states))
                return;

        states++; /* Total number of states is highest state + 1 */

        var = sizeof(*stats);
        var += sizeof(*stats->time_in_state) * states;
        var += sizeof(*stats->trans_table) * states * states;

        stats = kzalloc(var, GFP_KERNEL);
        if (!stats)
                return;

        stats->time_in_state = (ktime_t *)(stats + 1);
        stats->trans_table = (unsigned int *)(stats->time_in_state + states);
        cdev->stats = stats;
        stats->last_time = ktime_get();
        stats->max_states = states;

        spin_lock_init(&stats->lock);

        /* Fill the empty slot left in cooling_device_attr_groups */
        var = ARRAY_SIZE(cooling_device_attr_groups) - 2;
        cooling_device_attr_groups[var] = &cooling_device_stats_attr_group;
}

static void cooling_device_stats_destroy(struct thermal_cooling_device *cdev)
{
        kfree(cdev->stats);
        cdev->stats = NULL;
}

#else

static inline void
cooling_device_stats_setup(struct thermal_cooling_device *cdev) {}
static inline void
cooling_device_stats_destroy(struct thermal_cooling_device *cdev) {}

#endif /* CONFIG_THERMAL_STATISTICS */

void thermal_cooling_device_setup_sysfs(struct thermal_cooling_device *cdev)
{
        cooling_device_stats_setup(cdev);
        cdev->device.groups = cooling_device_attr_groups;
}

void thermal_cooling_device_destroy_sysfs(struct thermal_cooling_device *cdev)
{
        cooling_device_stats_destroy(cdev);
}

/* these helper will be used only at the time of bindig */
ssize_t
trip_point_show(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct thermal_instance *instance;

        instance =
            container_of(attr, struct thermal_instance, attr);

        return sprintf(buf, "%d\n", instance->trip);
}

ssize_t
weight_show(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct thermal_instance *instance;

        instance = container_of(attr, struct thermal_instance, weight_attr);

        return sprintf(buf, "%d\n", instance->weight);
}

ssize_t weight_store(struct device *dev, struct device_attribute *attr,
                     const char *buf, size_t count)
{
        struct thermal_instance *instance;
        int ret, weight;

        ret = kstrtoint(buf, 0, &weight);
        if (ret)
                return ret;

        instance = container_of(attr, struct thermal_instance, weight_attr);
        instance->weight = weight;

        return count;
}