// SPDX-License-Identifier: GPL-2.0
/*
 *  power_supply_hwmon.c - power supply hwmon support.
 */

#include <linux/err.h>
#include <linux/hwmon.h>
#include <linux/power_supply.h>
#include <linux/slab.h>
#include "power_supply.h"

struct power_supply_hwmon {
        struct power_supply *psy;
        unsigned long *props;
};

static const char *const ps_temp_label[] = {
        "temp",
        "ambient temp",
};

static int power_supply_hwmon_in_to_property(u32 attr)
{
        switch (attr) {
        case hwmon_in_average:
                return POWER_SUPPLY_PROP_VOLTAGE_AVG;
        case hwmon_in_min:
                return POWER_SUPPLY_PROP_VOLTAGE_MIN;
        case hwmon_in_max:
                return POWER_SUPPLY_PROP_VOLTAGE_MAX;
        case hwmon_in_input:
                return POWER_SUPPLY_PROP_VOLTAGE_NOW;
        default:
                return -EINVAL;
        }
}

static int power_supply_hwmon_curr_to_property(u32 attr)
{
        switch (attr) {
        case hwmon_curr_average:
                return POWER_SUPPLY_PROP_CURRENT_AVG;
        case hwmon_curr_max:
                return POWER_SUPPLY_PROP_CURRENT_MAX;
        case hwmon_curr_input:
                return POWER_SUPPLY_PROP_CURRENT_NOW;
        default:
                return -EINVAL;
        }
}

static int power_supply_hwmon_power_to_property(u32 attr)
{
        switch (attr) {
        case hwmon_power_input:
                return POWER_SUPPLY_PROP_POWER_NOW;
        case hwmon_power_average:
                return POWER_SUPPLY_PROP_POWER_AVG;
        default:
                return -EINVAL;
        }
}

static int power_supply_hwmon_temp_to_property(u32 attr, int channel)
{
        if (channel) {
                switch (attr) {
                case hwmon_temp_input:
                        return POWER_SUPPLY_PROP_TEMP_AMBIENT;
                case hwmon_temp_min_alarm:
                        return POWER_SUPPLY_PROP_TEMP_AMBIENT_ALERT_MIN;
                case hwmon_temp_max_alarm:
                        return POWER_SUPPLY_PROP_TEMP_AMBIENT_ALERT_MAX;
                default:
                        break;
                }
        } else {
                switch (attr) {
                case hwmon_temp_input:
                        return POWER_SUPPLY_PROP_TEMP;
                case hwmon_temp_max:
                        return POWER_SUPPLY_PROP_TEMP_MAX;
                case hwmon_temp_min:
                        return POWER_SUPPLY_PROP_TEMP_MIN;
                case hwmon_temp_min_alarm:
                        return POWER_SUPPLY_PROP_TEMP_ALERT_MIN;
                case hwmon_temp_max_alarm:
                        return POWER_SUPPLY_PROP_TEMP_ALERT_MAX;
                default:
                        break;
                }
        }

        return -EINVAL;
}

static int
power_supply_hwmon_to_property(enum hwmon_sensor_types type,
                               u32 attr, int channel)
{
        switch (type) {
        case hwmon_in:
                return power_supply_hwmon_in_to_property(attr);
        case hwmon_curr:
                return power_supply_hwmon_curr_to_property(attr);
        case hwmon_power:
                return power_supply_hwmon_power_to_property(attr);
        case hwmon_temp:
                return power_supply_hwmon_temp_to_property(attr, channel);
        default:
                return -EINVAL;
        }
}

static bool power_supply_hwmon_is_a_label(enum hwmon_sensor_types type,
                                           u32 attr)
{
        return type == hwmon_temp && attr == hwmon_temp_label;
}

struct hwmon_type_attr_list {
        const u32 *attrs;
        size_t n_attrs;
};

static const u32 ps_temp_attrs[] = {
        hwmon_temp_input,
        hwmon_temp_min, hwmon_temp_max,
        hwmon_temp_min_alarm, hwmon_temp_max_alarm,
};

static const struct hwmon_type_attr_list ps_type_attrs[hwmon_max] = {
        [hwmon_temp] = { ps_temp_attrs, ARRAY_SIZE(ps_temp_attrs) },
};

static bool power_supply_hwmon_has_input(
        const struct power_supply_hwmon *psyhw,
        enum hwmon_sensor_types type, int channel)
{
        const struct hwmon_type_attr_list *attr_list = &ps_type_attrs[type];
        size_t i;

        for (i = 0; i < attr_list->n_attrs; ++i) {
                int prop = power_supply_hwmon_to_property(type,
                        attr_list->attrs[i], channel);

                if (prop >= 0 && test_bit(prop, psyhw->props))
                        return true;
        }

        return false;
}

static bool power_supply_hwmon_is_writable(enum hwmon_sensor_types type,
                                           u32 attr)
{
        switch (type) {
        case hwmon_in:
                return attr == hwmon_in_min ||
                       attr == hwmon_in_max;
        case hwmon_curr:
                return attr == hwmon_curr_max;
        case hwmon_temp:
                return attr == hwmon_temp_max ||
                       attr == hwmon_temp_min ||
                       attr == hwmon_temp_min_alarm ||
                       attr == hwmon_temp_max_alarm;
        default:
                return false;
        }
}

static umode_t power_supply_hwmon_is_visible(const void *data,
                                             enum hwmon_sensor_types type,
                                             u32 attr, int channel)
{
        const struct power_supply_hwmon *psyhw = data;
        int prop;

        if (power_supply_hwmon_is_a_label(type, attr)) {
                if (power_supply_hwmon_has_input(psyhw, type, channel))
                        return 0444;
                else
                        return 0;
        }

        prop = power_supply_hwmon_to_property(type, attr, channel);
        if (prop < 0 || !test_bit(prop, psyhw->props))
                return 0;

        if (power_supply_property_is_writeable(psyhw->psy, prop) > 0 &&
            power_supply_hwmon_is_writable(type, attr))
                return 0644;

        return 0444;
}

static int power_supply_hwmon_read_string(struct device *dev,
                                          enum hwmon_sensor_types type,
                                          u32 attr, int channel,
                                          const char **str)
{
        switch (type) {
        case hwmon_temp:
                *str = ps_temp_label[channel];
                break;
        default:
                /* unreachable, but see:
                 * gcc bug #51513 [1] and clang bug #978 [2]
                 *
                 * [1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=51513
                 * [2] https://github.com/ClangBuiltLinux/linux/issues/978
                 */
                break;
        }

        return 0;
}

static int
power_supply_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
                        u32 attr, int channel, long *val)
{
        struct power_supply_hwmon *psyhw = dev_get_drvdata(dev);
        struct power_supply *psy = psyhw->psy;
        union power_supply_propval pspval;
        int ret, prop;

        prop = power_supply_hwmon_to_property(type, attr, channel);
        if (prop < 0)
                return prop;

        ret  = power_supply_get_property(psy, prop, &pspval);
        if (ret)
                return ret;

        switch (type) {
        /*
         * Both voltage and current is reported in units of
         * microvolts/microamps, so we need to adjust it to
         * milliamps(volts)
         */
        case hwmon_curr:
        case hwmon_in:
                pspval.intval = DIV_ROUND_CLOSEST(pspval.intval, 1000);
                break;
        case hwmon_power:
                /*
                 * Power properties are already in microwatts.
                 */
                break;
        /*
         * Temp needs to be converted from 1/10 C to milli-C
         */
        case hwmon_temp:
                if (check_mul_overflow(pspval.intval, 100,
                                       &pspval.intval))
                        return -EOVERFLOW;
                break;
        default:
                return -EINVAL;
        }

        *val = pspval.intval;

        return 0;
}

static int
power_supply_hwmon_write(struct device *dev, enum hwmon_sensor_types type,
                         u32 attr, int channel, long val)
{
        struct power_supply_hwmon *psyhw = dev_get_drvdata(dev);
        struct power_supply *psy = psyhw->psy;
        union power_supply_propval pspval;
        int prop;

        prop = power_supply_hwmon_to_property(type, attr, channel);
        if (prop < 0)
                return prop;

        pspval.intval = val;

        switch (type) {
        /*
         * Both voltage and current is reported in units of
         * microvolts/microamps, so we need to adjust it to
         * milliamps(volts)
         */
        case hwmon_curr:
        case hwmon_in:
                if (check_mul_overflow(pspval.intval, 1000,
                                       &pspval.intval))
                        return -EOVERFLOW;
                break;
        /*
         * Temp needs to be converted from 1/10 C to milli-C
         */
        case hwmon_temp:
                pspval.intval = DIV_ROUND_CLOSEST(pspval.intval, 100);
                break;
        default:
                return -EINVAL;
        }

        return power_supply_set_property(psy, prop, &pspval);
}

static const struct hwmon_ops power_supply_hwmon_ops = {
        .is_visible     = power_supply_hwmon_is_visible,
        .read           = power_supply_hwmon_read,
        .write          = power_supply_hwmon_write,
        .read_string    = power_supply_hwmon_read_string,
};

static const struct hwmon_channel_info * const power_supply_hwmon_info[] = {
        HWMON_CHANNEL_INFO(temp,
                           HWMON_T_LABEL     |
                           HWMON_T_INPUT     |
                           HWMON_T_MAX       |
                           HWMON_T_MIN       |
                           HWMON_T_MIN_ALARM |
                           HWMON_T_MAX_ALARM,

                           HWMON_T_LABEL     |
                           HWMON_T_INPUT     |
                           HWMON_T_MIN_ALARM |
                           HWMON_T_MAX_ALARM),

        HWMON_CHANNEL_INFO(curr,
                           HWMON_C_AVERAGE |
                           HWMON_C_MAX     |
                           HWMON_C_INPUT),

        HWMON_CHANNEL_INFO(power,
                           HWMON_P_INPUT |
                           HWMON_P_AVERAGE),

        HWMON_CHANNEL_INFO(in,
                           HWMON_I_AVERAGE |
                           HWMON_I_MIN     |
                           HWMON_I_MAX     |
                           HWMON_I_INPUT),
        NULL
};

static const struct hwmon_chip_info power_supply_hwmon_chip_info = {
        .ops = &power_supply_hwmon_ops,
        .info = power_supply_hwmon_info,
};

static const enum power_supply_property power_supply_hwmon_props[] = {
        POWER_SUPPLY_PROP_CURRENT_AVG,
        POWER_SUPPLY_PROP_CURRENT_MAX,
        POWER_SUPPLY_PROP_CURRENT_NOW,
        POWER_SUPPLY_PROP_POWER_AVG,
        POWER_SUPPLY_PROP_POWER_NOW,
        POWER_SUPPLY_PROP_TEMP,
        POWER_SUPPLY_PROP_TEMP_MAX,
        POWER_SUPPLY_PROP_TEMP_MIN,
        POWER_SUPPLY_PROP_TEMP_ALERT_MIN,
        POWER_SUPPLY_PROP_TEMP_ALERT_MAX,
        POWER_SUPPLY_PROP_TEMP_AMBIENT,
        POWER_SUPPLY_PROP_TEMP_AMBIENT_ALERT_MIN,
        POWER_SUPPLY_PROP_TEMP_AMBIENT_ALERT_MAX,
        POWER_SUPPLY_PROP_VOLTAGE_AVG,
        POWER_SUPPLY_PROP_VOLTAGE_MIN,
        POWER_SUPPLY_PROP_VOLTAGE_MAX,
        POWER_SUPPLY_PROP_VOLTAGE_NOW,
};

int power_supply_add_hwmon_sysfs(struct power_supply *psy)
{
        struct power_supply_hwmon *psyhw;
        struct device *dev = &psy->dev;
        struct device *hwmon;
        int ret, i;
        const char *name;

        if (!devres_open_group(dev, power_supply_add_hwmon_sysfs,
                               GFP_KERNEL))
                return -ENOMEM;

        psyhw = devm_kzalloc(dev, sizeof(*psyhw), GFP_KERNEL);
        if (!psyhw) {
                ret = -ENOMEM;
                goto error;
        }

        psyhw->psy = psy;
        psyhw->props = devm_bitmap_zalloc(dev,
                                          POWER_SUPPLY_PROP_TIME_TO_FULL_AVG + 1,
                                          GFP_KERNEL);
        if (!psyhw->props) {
                ret = -ENOMEM;
                goto error;
        }

        for (i = 0; i < ARRAY_SIZE(power_supply_hwmon_props); i++) {
                const enum power_supply_property prop = power_supply_hwmon_props[i];

                if (power_supply_has_property(psy, prop))
                        set_bit(prop, psyhw->props);
        }

        name = psy->desc->name;
        if (strchr(name, '-')) {
                char *new_name;

                new_name = devm_kstrdup(dev, name, GFP_KERNEL);
                if (!new_name) {
                        ret = -ENOMEM;
                        goto error;
                }
                strreplace(new_name, '-', '_');
                name = new_name;
        }
        hwmon = devm_hwmon_device_register_with_info(dev, name,
                                                psyhw,
                                                &power_supply_hwmon_chip_info,
                                                NULL);
        ret = PTR_ERR_OR_ZERO(hwmon);
        if (ret)
                goto error;

        devres_close_group(dev, power_supply_add_hwmon_sysfs);
        return 0;
error:
        devres_release_group(dev, NULL);
        return ret;
}

void power_supply_remove_hwmon_sysfs(struct power_supply *psy)
{
        devres_release_group(&psy->dev, power_supply_add_hwmon_sysfs);
}