// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * max6639.c - Support for Maxim MAX6639
 *
 * 2-Channel Temperature Monitor with Dual PWM Fan-Speed Controller
 *
 * Copyright (C) 2010, 2011 Roland Stigge <stigge@antcom.de>
 *
 * based on the initial MAX6639 support from semptian.net
 * by He Changqing <hechangqing@semptian.com>
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/jiffies.h>
#include <linux/i2c.h>
#include <linux/hwmon.h>
#include <linux/err.h>
#include <linux/regmap.h>
#include <linux/util_macros.h>

/* Addresses to scan */
static const unsigned short normal_i2c[] = { 0x2c, 0x2e, 0x2f, I2C_CLIENT_END };

/* The MAX6639 registers, valid channel numbers: 0, 1 */
#define MAX6639_REG_TEMP(ch)                    (0x00 + (ch))
#define MAX6639_REG_STATUS                      0x02
#define MAX6639_REG_OUTPUT_MASK                 0x03
#define MAX6639_REG_GCONFIG                     0x04
#define MAX6639_REG_TEMP_EXT(ch)                (0x05 + (ch))
#define MAX6639_REG_ALERT_LIMIT(ch)             (0x08 + (ch))
#define MAX6639_REG_OT_LIMIT(ch)                (0x0A + (ch))
#define MAX6639_REG_THERM_LIMIT(ch)             (0x0C + (ch))
#define MAX6639_REG_FAN_CONFIG1(ch)             (0x10 + (ch) * 4)
#define MAX6639_REG_FAN_CONFIG2a(ch)            (0x11 + (ch) * 4)
#define MAX6639_REG_FAN_CONFIG2b(ch)            (0x12 + (ch) * 4)
#define MAX6639_REG_FAN_CONFIG3(ch)             (0x13 + (ch) * 4)
#define MAX6639_REG_FAN_CNT(ch)                 (0x20 + (ch))
#define MAX6639_REG_TARGET_CNT(ch)              (0x22 + (ch))
#define MAX6639_REG_FAN_PPR(ch)                 (0x24 + (ch))
#define MAX6639_REG_TARGTDUTY(ch)               (0x26 + (ch))
#define MAX6639_REG_FAN_START_TEMP(ch)          (0x28 + (ch))
#define MAX6639_REG_DEVID                       0x3D
#define MAX6639_REG_MANUID                      0x3E
#define MAX6639_REG_DEVREV                      0x3F

/* Register bits */
#define MAX6639_GCONFIG_STANDBY                 0x80
#define MAX6639_GCONFIG_POR                     0x40
#define MAX6639_GCONFIG_DISABLE_TIMEOUT         0x20
#define MAX6639_GCONFIG_CH2_LOCAL               0x10
#define MAX6639_GCONFIG_PWM_FREQ_HI             0x08

#define MAX6639_FAN_CONFIG1_PWM                 0x80
#define MAX6639_FAN_CONFIG3_FREQ_MASK           0x03
#define MAX6639_FAN_CONFIG3_THERM_FULL_SPEED    0x40

#define MAX6639_NUM_CHANNELS                    2

static const int rpm_ranges[] = { 2000, 4000, 8000, 16000 };

/* Supported PWM frequency */
static const unsigned int freq_table[] = { 20, 33, 50, 100, 5000, 8333, 12500,
                                           25000 };

#define FAN_FROM_REG(val, rpm_range)    ((val) == 0 || (val) == 255 ? \
                                0 : (rpm_ranges[rpm_range] * 30) / (val))
#define TEMP_LIMIT_TO_REG(val)  clamp_val((val) / 1000, 0, 255)

/*
 * Client data (each client gets its own)
 */
struct max6639_data {
        struct regmap *regmap;

        /* Register values initialized only once */
        u8 ppr[MAX6639_NUM_CHANNELS];   /* Pulses per rotation 0..3 for 1..4 ppr */
        u8 rpm_range[MAX6639_NUM_CHANNELS]; /* Index in above rpm_ranges table */
        u32 target_rpm[MAX6639_NUM_CHANNELS];

        /* Optional regulator for FAN supply */
        struct regulator *reg;
};

static int max6639_temp_read_input(struct device *dev, int channel, long *temp)
{
        u32 regs[2] = { MAX6639_REG_TEMP_EXT(channel), MAX6639_REG_TEMP(channel) };
        struct max6639_data *data = dev_get_drvdata(dev);
        u8 regvals[2];
        int res;

        res = regmap_multi_reg_read(data->regmap, regs, regvals, 2);
        if (res < 0)
                return res;

        *temp = ((regvals[0] >> 5) | (regvals[1] << 3)) * 125;

        return 0;
}

static int max6639_temp_read_fault(struct device *dev, int channel, long *fault)
{
        struct max6639_data *data = dev_get_drvdata(dev);
        unsigned int val;
        int res;

        res = regmap_read(data->regmap, MAX6639_REG_TEMP_EXT(channel), &val);
        if (res < 0)
                return res;

        *fault = val & 1;

        return 0;
}

static int max6639_temp_read_max(struct device *dev, int channel, long *max)
{
        struct max6639_data *data = dev_get_drvdata(dev);
        unsigned int val;
        int res;

        res = regmap_read(data->regmap, MAX6639_REG_THERM_LIMIT(channel), &val);
        if (res < 0)
                return res;

        *max = (long)val * 1000;

        return 0;
}

static int max6639_temp_read_crit(struct device *dev, int channel, long *crit)
{
        struct max6639_data *data = dev_get_drvdata(dev);
        unsigned int val;
        int res;

        res = regmap_read(data->regmap, MAX6639_REG_ALERT_LIMIT(channel), &val);
        if (res < 0)
                return res;

        *crit = (long)val * 1000;

        return 0;
}

static int max6639_temp_read_emergency(struct device *dev, int channel, long *emerg)
{
        struct max6639_data *data = dev_get_drvdata(dev);
        unsigned int val;
        int res;

        res = regmap_read(data->regmap, MAX6639_REG_OT_LIMIT(channel), &val);
        if (res < 0)
                return res;

        *emerg = (long)val * 1000;

        return 0;
}

static int max6639_get_status(struct device *dev, unsigned int *status)
{
        struct max6639_data *data = dev_get_drvdata(dev);
        unsigned int val;
        int res;

        res = regmap_read(data->regmap, MAX6639_REG_STATUS, &val);
        if (res < 0)
                return res;

        *status = val;

        return 0;
}

static int max6639_temp_set_max(struct max6639_data *data, int channel, long val)
{
        int res;

        res = regmap_write(data->regmap, MAX6639_REG_THERM_LIMIT(channel),
                           TEMP_LIMIT_TO_REG(val));
        return res;
}

static int max6639_temp_set_crit(struct max6639_data *data, int channel, long val)
{
        int res;

        res = regmap_write(data->regmap, MAX6639_REG_ALERT_LIMIT(channel), TEMP_LIMIT_TO_REG(val));

        return res;
}

static int max6639_temp_set_emergency(struct max6639_data *data, int channel, long val)
{
        int res;

        res = regmap_write(data->regmap, MAX6639_REG_OT_LIMIT(channel), TEMP_LIMIT_TO_REG(val));

        return res;
}

static int max6639_read_fan(struct device *dev, u32 attr, int channel,
                            long *fan_val)
{
        struct max6639_data *data = dev_get_drvdata(dev);
        unsigned int val;
        int res;

        switch (attr) {
        case hwmon_fan_input:
                res = regmap_read(data->regmap, MAX6639_REG_FAN_CNT(channel), &val);
                if (res < 0)
                        return res;
                *fan_val = FAN_FROM_REG(val, data->rpm_range[channel]);
                return 0;
        case hwmon_fan_fault:
                res = max6639_get_status(dev, &val);
                if (res < 0)
                        return res;
                *fan_val = !!(val & BIT(1 - channel));
                return 0;
        case hwmon_fan_pulses:
                *fan_val = data->ppr[channel];
                return 0;
        default:
                return -EOPNOTSUPP;
        }
}

static int max6639_set_ppr(struct max6639_data *data, int channel, u8 ppr)
{
        /* Decrement the PPR value and shift left by 6 to match the register format */
        return regmap_write(data->regmap, MAX6639_REG_FAN_PPR(channel), --ppr << 6);
}

static int max6639_write_fan(struct device *dev, u32 attr, int channel,
                             long val)
{
        struct max6639_data *data = dev_get_drvdata(dev);
        int err;

        switch (attr) {
        case hwmon_fan_pulses:
                if (val <= 0 || val > 4)
                        return -EINVAL;

                /* Set Fan pulse per revolution */
                err = max6639_set_ppr(data, channel, val);
                if (err < 0)
                        return err;
                data->ppr[channel] = val;
                return 0;
        default:
                return -EOPNOTSUPP;
        }
}

static umode_t max6639_fan_is_visible(const void *_data, u32 attr, int channel)
{
        switch (attr) {
        case hwmon_fan_input:
        case hwmon_fan_fault:
                return 0444;
        case hwmon_fan_pulses:
                return 0644;
        default:
                return 0;
        }
}

static int max6639_read_pwm(struct device *dev, u32 attr, int channel,
                            long *pwm_val)
{
        u32 regs[2] = { MAX6639_REG_FAN_CONFIG3(channel), MAX6639_REG_GCONFIG };
        struct max6639_data *data = dev_get_drvdata(dev);
        unsigned int val;
        u8 regvals[2];
        int res;
        u8 i;

        switch (attr) {
        case hwmon_pwm_input:
                res = regmap_read(data->regmap, MAX6639_REG_TARGTDUTY(channel), &val);
                if (res < 0)
                        return res;
                *pwm_val = val * 255 / 120;
                return 0;
        case hwmon_pwm_freq:
                res = regmap_multi_reg_read(data->regmap, regs, regvals, 2);
                if (res < 0)
                        return res;
                i = regvals[0] & MAX6639_FAN_CONFIG3_FREQ_MASK;
                if (regvals[1] & MAX6639_GCONFIG_PWM_FREQ_HI)
                        i |= 0x4;
                *pwm_val = freq_table[i];
                return 0;
        default:
                return -EOPNOTSUPP;
        }
}

static int max6639_write_pwm(struct device *dev, u32 attr, int channel,
                             long val)
{
        struct max6639_data *data = dev_get_drvdata(dev);
        int err;
        u8 i;

        switch (attr) {
        case hwmon_pwm_input:
                if (val < 0 || val > 255)
                        return -EINVAL;
                return regmap_write(data->regmap, MAX6639_REG_TARGTDUTY(channel),
                                    val * 120 / 255);
        case hwmon_pwm_freq:
                val = clamp_val(val, 0, 25000);

                i = find_closest(val, freq_table, ARRAY_SIZE(freq_table));

                err = regmap_update_bits(data->regmap, MAX6639_REG_FAN_CONFIG3(channel),
                                         MAX6639_FAN_CONFIG3_FREQ_MASK, i);
                if (err < 0)
                        return err;

                if (i >> 2)
                        err = regmap_set_bits(data->regmap, MAX6639_REG_GCONFIG,
                                              MAX6639_GCONFIG_PWM_FREQ_HI);
                else
                        err = regmap_clear_bits(data->regmap, MAX6639_REG_GCONFIG,
                                                MAX6639_GCONFIG_PWM_FREQ_HI);

                return err;
        default:
                return -EOPNOTSUPP;
        }
}

static umode_t max6639_pwm_is_visible(const void *_data, u32 attr, int channel)
{
        switch (attr) {
        case hwmon_pwm_input:
        case hwmon_pwm_freq:
                return 0644;
        default:
                return 0;
        }
}

static int max6639_read_temp(struct device *dev, u32 attr, int channel,
                             long *val)
{
        unsigned int status;
        int res;

        switch (attr) {
        case hwmon_temp_input:
                res = max6639_temp_read_input(dev, channel, val);
                return res;
        case hwmon_temp_fault:
                res = max6639_temp_read_fault(dev, channel, val);
                return res;
        case hwmon_temp_max:
                res = max6639_temp_read_max(dev, channel, val);
                return res;
        case hwmon_temp_crit:
                res = max6639_temp_read_crit(dev, channel, val);
                return res;
        case hwmon_temp_emergency:
                res = max6639_temp_read_emergency(dev, channel, val);
                return res;
        case hwmon_temp_max_alarm:
                res = max6639_get_status(dev, &status);
                if (res < 0)
                        return res;
                *val = !!(status & BIT(3 - channel));
                return 0;
        case hwmon_temp_crit_alarm:
                res = max6639_get_status(dev, &status);
                if (res < 0)
                        return res;
                *val = !!(status & BIT(7 - channel));
                return 0;
        case hwmon_temp_emergency_alarm:
                res = max6639_get_status(dev, &status);
                if (res < 0)
                        return res;
                *val = !!(status & BIT(5 - channel));
                return 0;
        default:
                return -EOPNOTSUPP;
        }
}

static int max6639_write_temp(struct device *dev, u32 attr, int channel,
                              long val)
{
        struct max6639_data *data = dev_get_drvdata(dev);

        switch (attr) {
        case hwmon_temp_max:
                return max6639_temp_set_max(data, channel, val);
        case hwmon_temp_crit:
                return max6639_temp_set_crit(data, channel, val);
        case hwmon_temp_emergency:
                return max6639_temp_set_emergency(data, channel, val);
        default:
                return -EOPNOTSUPP;
        }
}

static umode_t max6639_temp_is_visible(const void *_data, u32 attr, int channel)
{
        switch (attr) {
        case hwmon_temp_input:
        case hwmon_temp_fault:
        case hwmon_temp_max_alarm:
        case hwmon_temp_crit_alarm:
        case hwmon_temp_emergency_alarm:
                return 0444;
        case hwmon_temp_max:
        case hwmon_temp_crit:
        case hwmon_temp_emergency:
                return 0644;
        default:
                return 0;
        }
}

static int max6639_read(struct device *dev, enum hwmon_sensor_types type,
                        u32 attr, int channel, long *val)
{
        switch (type) {
        case hwmon_fan:
                return max6639_read_fan(dev, attr, channel, val);
        case hwmon_pwm:
                return max6639_read_pwm(dev, attr, channel, val);
        case hwmon_temp:
                return max6639_read_temp(dev, attr, channel, val);
        default:
                return -EOPNOTSUPP;
        }
}

static int max6639_write(struct device *dev, enum hwmon_sensor_types type,
                         u32 attr, int channel, long val)
{
        switch (type) {
        case hwmon_fan:
                return max6639_write_fan(dev, attr, channel, val);
        case hwmon_pwm:
                return max6639_write_pwm(dev, attr, channel, val);
        case hwmon_temp:
                return max6639_write_temp(dev, attr, channel, val);
        default:
                return -EOPNOTSUPP;
        }
}

static umode_t max6639_is_visible(const void *data,
                                  enum hwmon_sensor_types type,
                                  u32 attr, int channel)
{
        switch (type) {
        case hwmon_fan:
                return max6639_fan_is_visible(data, attr, channel);
        case hwmon_pwm:
                return max6639_pwm_is_visible(data, attr, channel);
        case hwmon_temp:
                return max6639_temp_is_visible(data, attr, channel);
        default:
                return 0;
        }
}

static const struct hwmon_channel_info * const max6639_info[] = {
        HWMON_CHANNEL_INFO(fan,
                           HWMON_F_INPUT | HWMON_F_FAULT | HWMON_F_PULSES,
                           HWMON_F_INPUT | HWMON_F_FAULT | HWMON_F_PULSES),
        HWMON_CHANNEL_INFO(pwm,
                           HWMON_PWM_INPUT | HWMON_PWM_FREQ,
                           HWMON_PWM_INPUT | HWMON_PWM_FREQ),
        HWMON_CHANNEL_INFO(temp,
                           HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_MAX | HWMON_T_MAX_ALARM |
                           HWMON_T_CRIT | HWMON_T_CRIT_ALARM | HWMON_T_EMERGENCY |
                           HWMON_T_EMERGENCY_ALARM,
                           HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_MAX | HWMON_T_MAX_ALARM |
                           HWMON_T_CRIT | HWMON_T_CRIT_ALARM | HWMON_T_EMERGENCY |
                           HWMON_T_EMERGENCY_ALARM),
        NULL
};

static const struct hwmon_ops max6639_hwmon_ops = {
        .is_visible = max6639_is_visible,
        .read = max6639_read,
        .write = max6639_write,
};

static const struct hwmon_chip_info max6639_chip_info = {
        .ops = &max6639_hwmon_ops,
        .info = max6639_info,
};

/*
 *  returns respective index in rpm_ranges table
 *  1 by default on invalid range
 */
static int rpm_range_to_reg(int range)
{
        int i;

        for (i = 0; i < ARRAY_SIZE(rpm_ranges); i++) {
                if (rpm_ranges[i] == range)
                        return i;
        }

        return 1; /* default: 4000 RPM */
}

static int max6639_probe_child_from_dt(struct i2c_client *client,
                                       struct device_node *child,
                                       struct max6639_data *data)

{
        struct device *dev = &client->dev;
        u32 i, val;
        int err;

        err = of_property_read_u32(child, "reg", &i);
        if (err) {
                dev_err(dev, "missing reg property of %pOFn\n", child);
                return err;
        }

        if (i > 1) {
                dev_err(dev, "Invalid fan index reg %d\n", i);
                return -EINVAL;
        }

        err = of_property_read_u32(child, "pulses-per-revolution", &val);
        if (!err) {
                if (val < 1 || val > 4) {
                        dev_err(dev, "invalid pulses-per-revolution %u of %pOFn\n", val, child);
                        return -EINVAL;
                }
                data->ppr[i] = val;
        }

        err = of_property_read_u32(child, "max-rpm", &val);
        if (!err)
                data->rpm_range[i] = rpm_range_to_reg(val);

        err = of_property_read_u32(child, "target-rpm", &val);
        if (!err)
                data->target_rpm[i] = val;

        return 0;
}

static int max6639_init_client(struct i2c_client *client,
                               struct max6639_data *data)
{
        struct device *dev = &client->dev;
        const struct device_node *np = dev->of_node;
        int i, err;
        u8 target_duty;

        /* Reset chip to default values, see below for GCONFIG setup */
        err = regmap_write(data->regmap, MAX6639_REG_GCONFIG, MAX6639_GCONFIG_POR);
        if (err)
                return err;

        /* Fans pulse per revolution is 2 by default */
        data->ppr[0] = 2;
        data->ppr[1] = 2;

        /* default: 4000 RPM */
        data->rpm_range[0] = 1;
        data->rpm_range[1] = 1;
        data->target_rpm[0] = 4000;
        data->target_rpm[1] = 4000;

        for_each_child_of_node_scoped(np, child) {
                if (strcmp(child->name, "fan"))
                        continue;

                err = max6639_probe_child_from_dt(client, child, data);
                if (err)
                        return err;
        }

        for (i = 0; i < MAX6639_NUM_CHANNELS; i++) {
                err = regmap_set_bits(data->regmap, MAX6639_REG_OUTPUT_MASK, BIT(1 - i));
                if (err)
                        return err;

                /* Set Fan pulse per revolution */
                err = max6639_set_ppr(data, i, data->ppr[i]);
                if (err)
                        return err;

                /* Fans config PWM, RPM */
                err = regmap_write(data->regmap, MAX6639_REG_FAN_CONFIG1(i),
                                   MAX6639_FAN_CONFIG1_PWM | data->rpm_range[i]);
                if (err)
                        return err;

                /* Fans PWM polarity high by default */
                err = regmap_write(data->regmap, MAX6639_REG_FAN_CONFIG2a(i), 0x02);
                if (err)
                        return err;

                /*
                 * /THERM full speed enable,
                 * PWM frequency 25kHz, see also GCONFIG below
                 */
                err = regmap_write(data->regmap, MAX6639_REG_FAN_CONFIG3(i),
                                   MAX6639_FAN_CONFIG3_THERM_FULL_SPEED | 0x03);
                if (err)
                        return err;

                /* Max. temp. 80C/90C/100C */
                err = regmap_write(data->regmap, MAX6639_REG_THERM_LIMIT(i), 80);
                if (err)
                        return err;
                err = regmap_write(data->regmap, MAX6639_REG_ALERT_LIMIT(i), 90);
                if (err)
                        return err;
                err = regmap_write(data->regmap, MAX6639_REG_OT_LIMIT(i), 100);
                if (err)
                        return err;

                /* Set PWM based on target RPM if specified */
                if (data->target_rpm[i] >  rpm_ranges[data->rpm_range[i]])
                        data->target_rpm[i] = rpm_ranges[data->rpm_range[i]];

                target_duty = 120 * data->target_rpm[i] / rpm_ranges[data->rpm_range[i]];
                err = regmap_write(data->regmap, MAX6639_REG_TARGTDUTY(i), target_duty);
                if (err)
                        return err;
        }
        /* Start monitoring */
        return regmap_write(data->regmap, MAX6639_REG_GCONFIG,
                            MAX6639_GCONFIG_DISABLE_TIMEOUT | MAX6639_GCONFIG_CH2_LOCAL |
                            MAX6639_GCONFIG_PWM_FREQ_HI);

}

/* Return 0 if detection is successful, -ENODEV otherwise */
static int max6639_detect(struct i2c_client *client,
                          struct i2c_board_info *info)
{
        struct i2c_adapter *adapter = client->adapter;
        int dev_id, manu_id;

        if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
                return -ENODEV;

        /* Actual detection via device and manufacturer ID */
        dev_id = i2c_smbus_read_byte_data(client, MAX6639_REG_DEVID);
        manu_id = i2c_smbus_read_byte_data(client, MAX6639_REG_MANUID);
        if (dev_id != 0x58 || manu_id != 0x4D)
                return -ENODEV;

        strscpy(info->type, "max6639", I2C_NAME_SIZE);

        return 0;
}

static void max6639_regulator_disable(void *data)
{
        regulator_disable(data);
}

static bool max6639_regmap_is_volatile(struct device *dev, unsigned int reg)
{
        switch (reg) {
        case MAX6639_REG_TEMP(0):
        case MAX6639_REG_TEMP_EXT(0):
        case MAX6639_REG_TEMP(1):
        case MAX6639_REG_TEMP_EXT(1):
        case MAX6639_REG_STATUS:
        case MAX6639_REG_FAN_CNT(0):
        case MAX6639_REG_FAN_CNT(1):
        case MAX6639_REG_TARGTDUTY(0):
        case MAX6639_REG_TARGTDUTY(1):
                return true;
        default:
                return false;
        }
}

static const struct regmap_config max6639_regmap_config = {
        .reg_bits = 8,
        .val_bits = 8,
        .max_register = MAX6639_REG_DEVREV,
        .cache_type = REGCACHE_MAPLE,
        .volatile_reg = max6639_regmap_is_volatile,
};

static int max6639_probe(struct i2c_client *client)
{
        struct device *dev = &client->dev;
        struct max6639_data *data;
        struct device *hwmon_dev;
        int err;

        data = devm_kzalloc(dev, sizeof(struct max6639_data), GFP_KERNEL);
        if (!data)
                return -ENOMEM;

        data->regmap = devm_regmap_init_i2c(client, &max6639_regmap_config);
        if (IS_ERR(data->regmap))
                return dev_err_probe(dev,
                                     PTR_ERR(data->regmap),
                                     "regmap initialization failed\n");

        data->reg = devm_regulator_get_optional(dev, "fan");
        if (IS_ERR(data->reg)) {
                if (PTR_ERR(data->reg) != -ENODEV)
                        return PTR_ERR(data->reg);

                data->reg = NULL;
        } else {
                /* Spin up fans */
                err = regulator_enable(data->reg);
                if (err) {
                        dev_err(dev, "Failed to enable fan supply: %d\n", err);
                        return err;
                }
                err = devm_add_action_or_reset(dev, max6639_regulator_disable,
                                               data->reg);
                if (err) {
                        dev_err(dev, "Failed to register action: %d\n", err);
                        return err;
                }
        }

        /* Initialize the max6639 chip */
        err = max6639_init_client(client, data);
        if (err < 0)
                return err;

        hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
                                                         data, &max6639_chip_info,
                                                         NULL);

        return PTR_ERR_OR_ZERO(hwmon_dev);
}

static int max6639_suspend(struct device *dev)
{
        struct max6639_data *data = dev_get_drvdata(dev);

        if (data->reg)
                regulator_disable(data->reg);

        return regmap_write_bits(data->regmap, MAX6639_REG_GCONFIG, MAX6639_GCONFIG_STANDBY,
                                 MAX6639_GCONFIG_STANDBY);
}

static int max6639_resume(struct device *dev)
{
        struct max6639_data *data = dev_get_drvdata(dev);
        int ret;

        if (data->reg) {
                ret = regulator_enable(data->reg);
                if (ret) {
                        dev_err(dev, "Failed to enable fan supply: %d\n", ret);
                        return ret;
                }
        }

        return regmap_write_bits(data->regmap, MAX6639_REG_GCONFIG, MAX6639_GCONFIG_STANDBY,
                                 ~MAX6639_GCONFIG_STANDBY);
}

static const struct i2c_device_id max6639_id[] = {
        {"max6639"},
        { }
};

MODULE_DEVICE_TABLE(i2c, max6639_id);

static DEFINE_SIMPLE_DEV_PM_OPS(max6639_pm_ops, max6639_suspend, max6639_resume);

static const struct of_device_id max6639_of_match[] = {
        { .compatible = "maxim,max6639", },
        { },
};

static struct i2c_driver max6639_driver = {
        .class = I2C_CLASS_HWMON,
        .driver = {
                   .name = "max6639",
                   .pm = pm_sleep_ptr(&max6639_pm_ops),
                   .of_match_table = max6639_of_match,
                   },
        .probe = max6639_probe,
        .id_table = max6639_id,
        .detect = max6639_detect,
        .address_list = normal_i2c,
};

module_i2c_driver(max6639_driver);

MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
MODULE_DESCRIPTION("max6639 driver");
MODULE_LICENSE("GPL");