// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Hardware monitoring driver for LTC2978 and compatible chips.
 *
 * Copyright (c) 2011 Ericsson AB.
 * Copyright (c) 2013, 2014, 2015 Guenter Roeck
 * Copyright (c) 2015 Linear Technology
 * Copyright (c) 2018 Analog Devices Inc.
 */

#include <linux/delay.h>
#include <linux/jiffies.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include <linux/regulator/driver.h>
#include "pmbus.h"

enum chips {
        /* Managers */
        ltc2972, ltc2974, ltc2975, ltc2977, ltc2978, ltc2979, ltc2980,
        /* Controllers */
        ltc3880, ltc3882, ltc3883, ltc3884, ltc3886, ltc3887, ltc3889, ltc7880,
        /* Modules */
        ltm2987, ltm4664, ltm4675, ltm4676, ltm4677, ltm4678, ltm4680, ltm4686,
        ltm4700,
};

/* Common for all chips */
#define LTC2978_MFR_VOUT_PEAK           0xdd
#define LTC2978_MFR_VIN_PEAK            0xde
#define LTC2978_MFR_TEMPERATURE_PEAK    0xdf
#define LTC2978_MFR_SPECIAL_ID          0xe7    /* Undocumented on LTC3882 */
#define LTC2978_MFR_COMMON              0xef

/* LTC2974, LTC2975, LCT2977, LTC2980, LTC2978, and LTM2987 */
#define LTC2978_MFR_VOUT_MIN            0xfb
#define LTC2978_MFR_VIN_MIN             0xfc
#define LTC2978_MFR_TEMPERATURE_MIN     0xfd

/* LTC2974, LTC2975 */
#define LTC2974_MFR_IOUT_PEAK           0xd7
#define LTC2974_MFR_IOUT_MIN            0xd8

/* LTC3880, LTC3882, LTC3883, LTC3887, LTM4675, and LTM4676 */
#define LTC3880_MFR_IOUT_PEAK           0xd7
#define LTC3880_MFR_CLEAR_PEAKS         0xe3
#define LTC3880_MFR_TEMPERATURE2_PEAK   0xf4

/* LTC3883, LTC3884, LTC3886, LTC3889 and LTC7880 only */
#define LTC3883_MFR_IIN_PEAK            0xe1


/* LTC2975 only */
#define LTC2975_MFR_IIN_PEAK            0xc4
#define LTC2975_MFR_IIN_MIN             0xc5
#define LTC2975_MFR_PIN_PEAK            0xc6
#define LTC2975_MFR_PIN_MIN             0xc7

#define LTC2978_ID_MASK                 0xfff0

#define LTC2972_ID                      0x0310
#define LTC2974_ID                      0x0210
#define LTC2975_ID                      0x0220
#define LTC2977_ID                      0x0130
#define LTC2978_ID_REV1                 0x0110  /* Early revision */
#define LTC2978_ID_REV2                 0x0120
#define LTC2979_ID_A                    0x8060
#define LTC2979_ID_B                    0x8070
#define LTC2980_ID_A                    0x8030  /* A/B for two die IDs */
#define LTC2980_ID_B                    0x8040
#define LTC3880_ID                      0x4020
#define LTC3882_ID                      0x4200
#define LTC3882_ID_D1                   0x4240  /* Dash 1 */
#define LTC3883_ID                      0x4300
#define LTC3884_ID                      0x4C00
#define LTC3886_ID                      0x4600
#define LTC3887_ID                      0x4700
#define LTM2987_ID_A                    0x8010  /* A/B for two die IDs */
#define LTM2987_ID_B                    0x8020
#define LTC3889_ID                      0x4900
#define LTC7880_ID                      0x49E0
#define LTM4664_ID                      0x4120
#define LTM4675_ID                      0x47a0
#define LTM4676_ID_REV1                 0x4400
#define LTM4676_ID_REV2                 0x4480
#define LTM4676A_ID                     0x47e0
#define LTM4677_ID_REV1                 0x47B0
#define LTM4677_ID_REV2                 0x47D0
#define LTM4678_ID_REV1                 0x4100
#define LTM4678_ID_REV2                 0x4110
#define LTM4680_ID                      0x4140
#define LTM4686_ID                      0x4770
#define LTM4700_ID                      0x4130

#define LTC2972_NUM_PAGES               2
#define LTC2974_NUM_PAGES               4
#define LTC2978_NUM_PAGES               8
#define LTC3880_NUM_PAGES               2
#define LTC3883_NUM_PAGES               1

#define LTC_POLL_TIMEOUT                100     /* in milli-seconds */

#define LTC_NOT_BUSY                    BIT(6)
#define LTC_NOT_PENDING                 BIT(5)

/*
 * LTC2978 clears peak data whenever the CLEAR_FAULTS command is executed, which
 * happens pretty much each time chip data is updated. Raw peak data therefore
 * does not provide much value. To be able to provide useful peak data, keep an
 * internal cache of measured peak data, which is only cleared if an explicit
 * "clear peak" command is executed for the sensor in question.
 */

struct ltc2978_data {
        enum chips id;
        u16 vin_min, vin_max;
        u16 temp_min[LTC2974_NUM_PAGES], temp_max[LTC2974_NUM_PAGES];
        u16 vout_min[LTC2978_NUM_PAGES], vout_max[LTC2978_NUM_PAGES];
        u16 iout_min[LTC2974_NUM_PAGES], iout_max[LTC2974_NUM_PAGES];
        u16 iin_min, iin_max;
        u16 pin_min, pin_max;
        u16 temp2_max;
        struct pmbus_driver_info info;
        u32 features;
};
#define to_ltc2978_data(x)  container_of(x, struct ltc2978_data, info)

#define FEAT_CLEAR_PEAKS        BIT(0)
#define FEAT_NEEDS_POLLING      BIT(1)

#define has_clear_peaks(d)      ((d)->features & FEAT_CLEAR_PEAKS)
#define needs_polling(d)        ((d)->features & FEAT_NEEDS_POLLING)

static int ltc_wait_ready(struct i2c_client *client)
{
        unsigned long timeout = jiffies + msecs_to_jiffies(LTC_POLL_TIMEOUT);
        const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
        struct ltc2978_data *data = to_ltc2978_data(info);
        int status;
        u8 mask;

        if (!needs_polling(data))
                return 0;

        /*
         * LTC3883 does not support LTC_NOT_PENDING, even though
         * the datasheet claims that it does.
         */
        mask = LTC_NOT_BUSY;
        if (data->id != ltc3883)
                mask |= LTC_NOT_PENDING;

        do {
                status = pmbus_read_byte_data(client, 0, LTC2978_MFR_COMMON);
                if (status == -EBADMSG || status == -ENXIO) {
                        /* PEC error or NACK: chip may be busy, try again */
                        usleep_range(50, 100);
                        continue;
                }
                if (status < 0)
                        return status;

                if ((status & mask) == mask)
                        return 0;

                usleep_range(50, 100);
        } while (time_before(jiffies, timeout));

        return -ETIMEDOUT;
}

static int ltc_read_word_data(struct i2c_client *client, int page, int phase,
                              int reg)
{
        int ret;

        ret = ltc_wait_ready(client);
        if (ret < 0)
                return ret;

        return pmbus_read_word_data(client, page, 0xff, reg);
}

static int ltc_read_byte_data(struct i2c_client *client, int page, int reg)
{
        int ret;

        ret = ltc_wait_ready(client);
        if (ret < 0)
                return ret;

        return pmbus_read_byte_data(client, page, reg);
}

static int ltc_write_byte(struct i2c_client *client, int page, u8 byte)
{
        int ret;

        ret = ltc_wait_ready(client);
        if (ret < 0)
                return ret;

        return pmbus_write_byte(client, page, byte);
}

static inline int lin11_to_val(int data)
{
        s16 e = ((s16)data) >> 11;
        s32 m = (((s16)(data << 5)) >> 5);

        /*
         * mantissa is 10 bit + sign, exponent adds up to 15 bit.
         * Add 6 bit to exponent for maximum accuracy (10 + 15 + 6 = 31).
         */
        e += 6;
        return (e < 0 ? m >> -e : m << e);
}

static int ltc_get_max(struct ltc2978_data *data, struct i2c_client *client,
                       int page, int reg, u16 *pmax)
{
        int ret;

        ret = ltc_read_word_data(client, page, 0xff, reg);
        if (ret >= 0) {
                if (lin11_to_val(ret) > lin11_to_val(*pmax))
                        *pmax = ret;
                ret = *pmax;
        }
        return ret;
}

static int ltc_get_min(struct ltc2978_data *data, struct i2c_client *client,
                       int page, int reg, u16 *pmin)
{
        int ret;

        ret = ltc_read_word_data(client, page, 0xff, reg);
        if (ret >= 0) {
                if (lin11_to_val(ret) < lin11_to_val(*pmin))
                        *pmin = ret;
                ret = *pmin;
        }
        return ret;
}

static int ltc2978_read_word_data_common(struct i2c_client *client, int page,
                                         int reg)
{
        const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
        struct ltc2978_data *data = to_ltc2978_data(info);
        int ret;

        switch (reg) {
        case PMBUS_VIRT_READ_VIN_MAX:
                ret = ltc_get_max(data, client, page, LTC2978_MFR_VIN_PEAK,
                                  &data->vin_max);
                break;
        case PMBUS_VIRT_READ_VOUT_MAX:
                ret = ltc_read_word_data(client, page, 0xff,
                                         LTC2978_MFR_VOUT_PEAK);
                if (ret >= 0) {
                        /*
                         * VOUT is 16 bit unsigned with fixed exponent,
                         * so we can compare it directly
                         */
                        if (ret > data->vout_max[page])
                                data->vout_max[page] = ret;
                        ret = data->vout_max[page];
                }
                break;
        case PMBUS_VIRT_READ_TEMP_MAX:
                ret = ltc_get_max(data, client, page,
                                  LTC2978_MFR_TEMPERATURE_PEAK,
                                  &data->temp_max[page]);
                break;
        case PMBUS_VIRT_RESET_VOUT_HISTORY:
        case PMBUS_VIRT_RESET_VIN_HISTORY:
        case PMBUS_VIRT_RESET_TEMP_HISTORY:
                ret = 0;
                break;
        default:
                ret = ltc_wait_ready(client);
                if (ret < 0)
                        return ret;
                ret = -ENODATA;
                break;
        }
        return ret;
}

static int ltc2978_read_word_data(struct i2c_client *client, int page,
                                  int phase, int reg)
{
        const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
        struct ltc2978_data *data = to_ltc2978_data(info);
        int ret;

        switch (reg) {
        case PMBUS_VIRT_READ_VIN_MIN:
                ret = ltc_get_min(data, client, page, LTC2978_MFR_VIN_MIN,
                                  &data->vin_min);
                break;
        case PMBUS_VIRT_READ_VOUT_MIN:
                ret = ltc_read_word_data(client, page, phase,
                                         LTC2978_MFR_VOUT_MIN);
                if (ret >= 0) {
                        /*
                         * VOUT_MIN is known to not be supported on some lots
                         * of LTC2978 revision 1, and will return the maximum
                         * possible voltage if read. If VOUT_MAX is valid and
                         * lower than the reading of VOUT_MIN, use it instead.
                         */
                        if (data->vout_max[page] && ret > data->vout_max[page])
                                ret = data->vout_max[page];
                        if (ret < data->vout_min[page])
                                data->vout_min[page] = ret;
                        ret = data->vout_min[page];
                }
                break;
        case PMBUS_VIRT_READ_TEMP_MIN:
                ret = ltc_get_min(data, client, page,
                                  LTC2978_MFR_TEMPERATURE_MIN,
                                  &data->temp_min[page]);
                break;
        case PMBUS_VIRT_READ_IOUT_MAX:
        case PMBUS_VIRT_RESET_IOUT_HISTORY:
        case PMBUS_VIRT_READ_TEMP2_MAX:
        case PMBUS_VIRT_RESET_TEMP2_HISTORY:
                ret = -ENXIO;
                break;
        default:
                ret = ltc2978_read_word_data_common(client, page, reg);
                break;
        }
        return ret;
}

static int ltc2974_read_word_data(struct i2c_client *client, int page,
                                  int phase, int reg)
{
        const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
        struct ltc2978_data *data = to_ltc2978_data(info);
        int ret;

        switch (reg) {
        case PMBUS_VIRT_READ_IOUT_MAX:
                ret = ltc_get_max(data, client, page, LTC2974_MFR_IOUT_PEAK,
                                  &data->iout_max[page]);
                break;
        case PMBUS_VIRT_READ_IOUT_MIN:
                ret = ltc_get_min(data, client, page, LTC2974_MFR_IOUT_MIN,
                                  &data->iout_min[page]);
                break;
        case PMBUS_VIRT_RESET_IOUT_HISTORY:
                ret = 0;
                break;
        default:
                ret = ltc2978_read_word_data(client, page, phase, reg);
                break;
        }
        return ret;
}

static int ltc2975_read_word_data(struct i2c_client *client, int page,
                                  int phase, int reg)
{
        const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
        struct ltc2978_data *data = to_ltc2978_data(info);
        int ret;

        switch (reg) {
        case PMBUS_VIRT_READ_IIN_MAX:
                ret = ltc_get_max(data, client, page, LTC2975_MFR_IIN_PEAK,
                                  &data->iin_max);
                break;
        case PMBUS_VIRT_READ_IIN_MIN:
                ret = ltc_get_min(data, client, page, LTC2975_MFR_IIN_MIN,
                                  &data->iin_min);
                break;
        case PMBUS_VIRT_READ_PIN_MAX:
                ret = ltc_get_max(data, client, page, LTC2975_MFR_PIN_PEAK,
                                  &data->pin_max);
                break;
        case PMBUS_VIRT_READ_PIN_MIN:
                ret = ltc_get_min(data, client, page, LTC2975_MFR_PIN_MIN,
                                  &data->pin_min);
                break;
        case PMBUS_VIRT_RESET_IIN_HISTORY:
        case PMBUS_VIRT_RESET_PIN_HISTORY:
                ret = 0;
                break;
        default:
                ret = ltc2978_read_word_data(client, page, phase, reg);
                break;
        }
        return ret;
}

static int ltc3880_read_word_data(struct i2c_client *client, int page,
                                  int phase, int reg)
{
        const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
        struct ltc2978_data *data = to_ltc2978_data(info);
        int ret;

        switch (reg) {
        case PMBUS_VIRT_READ_IOUT_MAX:
                ret = ltc_get_max(data, client, page, LTC3880_MFR_IOUT_PEAK,
                                  &data->iout_max[page]);
                break;
        case PMBUS_VIRT_READ_TEMP2_MAX:
                ret = ltc_get_max(data, client, page,
                                  LTC3880_MFR_TEMPERATURE2_PEAK,
                                  &data->temp2_max);
                break;
        case PMBUS_VIRT_READ_VIN_MIN:
        case PMBUS_VIRT_READ_VOUT_MIN:
        case PMBUS_VIRT_READ_TEMP_MIN:
                ret = -ENXIO;
                break;
        case PMBUS_VIRT_RESET_IOUT_HISTORY:
        case PMBUS_VIRT_RESET_TEMP2_HISTORY:
                ret = 0;
                break;
        default:
                ret = ltc2978_read_word_data_common(client, page, reg);
                break;
        }
        return ret;
}

static int ltc3883_read_word_data(struct i2c_client *client, int page,
                                  int phase, int reg)
{
        const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
        struct ltc2978_data *data = to_ltc2978_data(info);
        int ret;

        switch (reg) {
        case PMBUS_VIRT_READ_IIN_MAX:
                ret = ltc_get_max(data, client, page, LTC3883_MFR_IIN_PEAK,
                                  &data->iin_max);
                break;
        case PMBUS_VIRT_RESET_IIN_HISTORY:
                ret = 0;
                break;
        default:
                ret = ltc3880_read_word_data(client, page, phase, reg);
                break;
        }
        return ret;
}

static int ltc2978_clear_peaks(struct ltc2978_data *data,
                               struct i2c_client *client, int page)
{
        int ret;

        if (has_clear_peaks(data))
                ret = ltc_write_byte(client, 0, LTC3880_MFR_CLEAR_PEAKS);
        else
                ret = ltc_write_byte(client, page, PMBUS_CLEAR_FAULTS);

        return ret;
}

static int ltc2978_write_word_data(struct i2c_client *client, int page,
                                    int reg, u16 word)
{
        const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
        struct ltc2978_data *data = to_ltc2978_data(info);
        int ret;

        switch (reg) {
        case PMBUS_VIRT_RESET_IIN_HISTORY:
                data->iin_max = 0x7c00;
                data->iin_min = 0x7bff;
                ret = ltc2978_clear_peaks(data, client, 0);
                break;
        case PMBUS_VIRT_RESET_PIN_HISTORY:
                data->pin_max = 0x7c00;
                data->pin_min = 0x7bff;
                ret = ltc2978_clear_peaks(data, client, 0);
                break;
        case PMBUS_VIRT_RESET_IOUT_HISTORY:
                data->iout_max[page] = 0x7c00;
                data->iout_min[page] = 0xfbff;
                ret = ltc2978_clear_peaks(data, client, page);
                break;
        case PMBUS_VIRT_RESET_TEMP2_HISTORY:
                data->temp2_max = 0x7c00;
                ret = ltc2978_clear_peaks(data, client, page);
                break;
        case PMBUS_VIRT_RESET_VOUT_HISTORY:
                data->vout_min[page] = 0xffff;
                data->vout_max[page] = 0;
                ret = ltc2978_clear_peaks(data, client, page);
                break;
        case PMBUS_VIRT_RESET_VIN_HISTORY:
                data->vin_min = 0x7bff;
                data->vin_max = 0x7c00;
                ret = ltc2978_clear_peaks(data, client, page);
                break;
        case PMBUS_VIRT_RESET_TEMP_HISTORY:
                data->temp_min[page] = 0x7bff;
                data->temp_max[page] = 0x7c00;
                ret = ltc2978_clear_peaks(data, client, page);
                break;
        default:
                ret = ltc_wait_ready(client);
                if (ret < 0)
                        return ret;
                ret = -ENODATA;
                break;
        }
        return ret;
}

static const struct i2c_device_id ltc2978_id[] = {
        {"ltc2972", ltc2972},
        {"ltc2974", ltc2974},
        {"ltc2975", ltc2975},
        {"ltc2977", ltc2977},
        {"ltc2978", ltc2978},
        {"ltc2979", ltc2979},
        {"ltc2980", ltc2980},
        {"ltc3880", ltc3880},
        {"ltc3882", ltc3882},
        {"ltc3883", ltc3883},
        {"ltc3884", ltc3884},
        {"ltc3886", ltc3886},
        {"ltc3887", ltc3887},
        {"ltc3889", ltc3889},
        {"ltc7880", ltc7880},
        {"ltm2987", ltm2987},
        {"ltm4664", ltm4664},
        {"ltm4675", ltm4675},
        {"ltm4676", ltm4676},
        {"ltm4677", ltm4677},
        {"ltm4678", ltm4678},
        {"ltm4680", ltm4680},
        {"ltm4686", ltm4686},
        {"ltm4700", ltm4700},
        {}
};
MODULE_DEVICE_TABLE(i2c, ltc2978_id);

#if IS_ENABLED(CONFIG_SENSORS_LTC2978_REGULATOR)
static const struct regulator_desc ltc2978_reg_desc[] = {
        PMBUS_REGULATOR("vout", 0),
        PMBUS_REGULATOR("vout", 1),
        PMBUS_REGULATOR("vout", 2),
        PMBUS_REGULATOR("vout", 3),
        PMBUS_REGULATOR("vout", 4),
        PMBUS_REGULATOR("vout", 5),
        PMBUS_REGULATOR("vout", 6),
        PMBUS_REGULATOR("vout", 7),
};
#endif /* CONFIG_SENSORS_LTC2978_REGULATOR */

static int ltc2978_get_id(struct i2c_client *client)
{
        int chip_id;

        chip_id = i2c_smbus_read_word_data(client, LTC2978_MFR_SPECIAL_ID);
        if (chip_id < 0) {
                const struct i2c_device_id *id;
                u8 buf[I2C_SMBUS_BLOCK_MAX];
                int ret;

                if (!i2c_check_functionality(client->adapter,
                                             I2C_FUNC_SMBUS_READ_BLOCK_DATA))
                        return -ENODEV;

                ret = i2c_smbus_read_block_data(client, PMBUS_MFR_ID, buf);
                if (ret < 0)
                        return ret;
                if (ret < 3 || strncmp(buf, "LTC", 3))
                        return -ENODEV;

                ret = i2c_smbus_read_block_data(client, PMBUS_MFR_MODEL, buf);
                if (ret < 0)
                        return ret;
                for (id = &ltc2978_id[0]; strlen(id->name); id++) {
                        if (!strncasecmp(id->name, buf, strlen(id->name)))
                                return (int)id->driver_data;
                }
                return -ENODEV;
        }

        chip_id &= LTC2978_ID_MASK;

        if (chip_id == LTC2972_ID)
                return ltc2972;
        else if (chip_id == LTC2974_ID)
                return ltc2974;
        else if (chip_id == LTC2975_ID)
                return ltc2975;
        else if (chip_id == LTC2977_ID)
                return ltc2977;
        else if (chip_id == LTC2978_ID_REV1 || chip_id == LTC2978_ID_REV2)
                return ltc2978;
        else if (chip_id == LTC2979_ID_A || chip_id == LTC2979_ID_B)
                return ltc2979;
        else if (chip_id == LTC2980_ID_A || chip_id == LTC2980_ID_B)
                return ltc2980;
        else if (chip_id == LTC3880_ID)
                return ltc3880;
        else if (chip_id == LTC3882_ID || chip_id == LTC3882_ID_D1)
                return ltc3882;
        else if (chip_id == LTC3883_ID)
                return ltc3883;
        else if (chip_id == LTC3884_ID)
                return ltc3884;
        else if (chip_id == LTC3886_ID)
                return ltc3886;
        else if (chip_id == LTC3887_ID)
                return ltc3887;
        else if (chip_id == LTC3889_ID)
                return ltc3889;
        else if (chip_id == LTC7880_ID)
                return ltc7880;
        else if (chip_id == LTM2987_ID_A || chip_id == LTM2987_ID_B)
                return ltm2987;
        else if (chip_id == LTM4664_ID)
                return ltm4664;
        else if (chip_id == LTM4675_ID)
                return ltm4675;
        else if (chip_id == LTM4676_ID_REV1 || chip_id == LTM4676_ID_REV2 ||
                 chip_id == LTM4676A_ID)
                return ltm4676;
        else if (chip_id == LTM4677_ID_REV1 || chip_id == LTM4677_ID_REV2)
                return ltm4677;
        else if (chip_id == LTM4678_ID_REV1 || chip_id == LTM4678_ID_REV2)
                return ltm4678;
        else if (chip_id == LTM4680_ID)
                return ltm4680;
        else if (chip_id == LTM4686_ID)
                return ltm4686;
        else if (chip_id == LTM4700_ID)
                return ltm4700;

        dev_err(&client->dev, "Unsupported chip ID 0x%x\n", chip_id);
        return -ENODEV;
}

static int ltc2978_probe(struct i2c_client *client)
{
        int i, chip_id;
        struct ltc2978_data *data;
        struct pmbus_driver_info *info;
        const struct i2c_device_id *id;

        if (!i2c_check_functionality(client->adapter,
                                     I2C_FUNC_SMBUS_READ_WORD_DATA))
                return -ENODEV;

        data = devm_kzalloc(&client->dev, sizeof(struct ltc2978_data),
                            GFP_KERNEL);
        if (!data)
                return -ENOMEM;

        chip_id = ltc2978_get_id(client);
        if (chip_id < 0)
                return chip_id;

        data->id = chip_id;
        id = i2c_match_id(ltc2978_id, client);
        if (data->id != id->driver_data)
                dev_warn(&client->dev,
                         "Device mismatch: Configured %s (%d), detected %d\n",
                         id->name,
                         (int) id->driver_data,
                         chip_id);

        info = &data->info;
        info->write_word_data = ltc2978_write_word_data;
        info->write_byte = ltc_write_byte;
        info->read_word_data = ltc_read_word_data;
        info->read_byte_data = ltc_read_byte_data;

        data->vin_min = 0x7bff;
        data->vin_max = 0x7c00;
        for (i = 0; i < ARRAY_SIZE(data->vout_min); i++)
                data->vout_min[i] = 0xffff;
        for (i = 0; i < ARRAY_SIZE(data->iout_min); i++)
                data->iout_min[i] = 0xfbff;
        for (i = 0; i < ARRAY_SIZE(data->iout_max); i++)
                data->iout_max[i] = 0x7c00;
        for (i = 0; i < ARRAY_SIZE(data->temp_min); i++)
                data->temp_min[i] = 0x7bff;
        for (i = 0; i < ARRAY_SIZE(data->temp_max); i++)
                data->temp_max[i] = 0x7c00;
        data->temp2_max = 0x7c00;

        switch (data->id) {
        case ltc2972:
                info->read_word_data = ltc2975_read_word_data;
                info->pages = LTC2972_NUM_PAGES;
                info->func[0] = PMBUS_HAVE_IIN | PMBUS_HAVE_PIN
                  | PMBUS_HAVE_VIN | PMBUS_HAVE_STATUS_INPUT
                  | PMBUS_HAVE_TEMP2;
                for (i = 0; i < info->pages; i++) {
                        info->func[i] |= PMBUS_HAVE_VOUT
                          | PMBUS_HAVE_STATUS_VOUT | PMBUS_HAVE_POUT
                          | PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP
                          | PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT;
                }
                break;
        case ltc2974:
                info->read_word_data = ltc2974_read_word_data;
                info->pages = LTC2974_NUM_PAGES;
                info->func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_STATUS_INPUT
                  | PMBUS_HAVE_TEMP2;
                for (i = 0; i < info->pages; i++) {
                        info->func[i] |= PMBUS_HAVE_VOUT
                          | PMBUS_HAVE_STATUS_VOUT | PMBUS_HAVE_POUT
                          | PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP
                          | PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT;
                }
                break;
        case ltc2975:
                info->read_word_data = ltc2975_read_word_data;
                info->pages = LTC2974_NUM_PAGES;
                info->func[0] = PMBUS_HAVE_IIN | PMBUS_HAVE_PIN
                  | PMBUS_HAVE_VIN | PMBUS_HAVE_STATUS_INPUT
                  | PMBUS_HAVE_TEMP2;
                for (i = 0; i < info->pages; i++) {
                        info->func[i] |= PMBUS_HAVE_VOUT
                          | PMBUS_HAVE_STATUS_VOUT | PMBUS_HAVE_POUT
                          | PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP
                          | PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT;
                }
                break;

        case ltc2977:
        case ltc2978:
        case ltc2979:
        case ltc2980:
        case ltm2987:
                info->read_word_data = ltc2978_read_word_data;
                info->pages = LTC2978_NUM_PAGES;
                info->func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_STATUS_INPUT
                  | PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT
                  | PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP;
                for (i = 1; i < LTC2978_NUM_PAGES; i++) {
                        info->func[i] = PMBUS_HAVE_VOUT
                          | PMBUS_HAVE_STATUS_VOUT;
                }
                break;
        case ltc3880:
        case ltc3887:
        case ltm4675:
        case ltm4676:
        case ltm4677:
        case ltm4686:
                data->features |= FEAT_CLEAR_PEAKS | FEAT_NEEDS_POLLING;
                info->read_word_data = ltc3880_read_word_data;
                info->pages = LTC3880_NUM_PAGES;
                info->func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_IIN
                  | PMBUS_HAVE_STATUS_INPUT
                  | PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT
                  | PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT
                  | PMBUS_HAVE_POUT | PMBUS_HAVE_TEMP
                  | PMBUS_HAVE_TEMP2 | PMBUS_HAVE_STATUS_TEMP;
                info->func[1] = PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT
                  | PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT
                  | PMBUS_HAVE_POUT
                  | PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP;
                break;
        case ltc3882:
                data->features |= FEAT_CLEAR_PEAKS | FEAT_NEEDS_POLLING;
                info->read_word_data = ltc3880_read_word_data;
                info->pages = LTC3880_NUM_PAGES;
                info->func[0] = PMBUS_HAVE_VIN
                  | PMBUS_HAVE_STATUS_INPUT
                  | PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT
                  | PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT
                  | PMBUS_HAVE_POUT | PMBUS_HAVE_TEMP
                  | PMBUS_HAVE_TEMP2 | PMBUS_HAVE_STATUS_TEMP;
                info->func[1] = PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT
                  | PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT
                  | PMBUS_HAVE_POUT
                  | PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP;
                break;
        case ltc3883:
                data->features |= FEAT_CLEAR_PEAKS | FEAT_NEEDS_POLLING;
                info->read_word_data = ltc3883_read_word_data;
                info->pages = LTC3883_NUM_PAGES;
                info->func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_IIN
                  | PMBUS_HAVE_STATUS_INPUT
                  | PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT
                  | PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT
                  | PMBUS_HAVE_PIN | PMBUS_HAVE_POUT | PMBUS_HAVE_TEMP
                  | PMBUS_HAVE_TEMP2 | PMBUS_HAVE_STATUS_TEMP;
                break;
        case ltc3884:
        case ltc3886:
        case ltc3889:
        case ltc7880:
        case ltm4664:
        case ltm4678:
        case ltm4680:
        case ltm4700:
                data->features |= FEAT_CLEAR_PEAKS | FEAT_NEEDS_POLLING;
                info->read_word_data = ltc3883_read_word_data;
                info->pages = LTC3880_NUM_PAGES;
                info->func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_IIN
                  | PMBUS_HAVE_STATUS_INPUT
                  | PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT
                  | PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT
                  | PMBUS_HAVE_PIN | PMBUS_HAVE_POUT | PMBUS_HAVE_TEMP
                  | PMBUS_HAVE_TEMP2 | PMBUS_HAVE_STATUS_TEMP;
                info->func[1] = PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT
                  | PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT
                  | PMBUS_HAVE_POUT
                  | PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP;
                break;
        default:
                return -ENODEV;
        }

#if IS_ENABLED(CONFIG_SENSORS_LTC2978_REGULATOR)
        info->num_regulators = info->pages;
        info->reg_desc = ltc2978_reg_desc;
        if (info->num_regulators > ARRAY_SIZE(ltc2978_reg_desc)) {
                dev_err(&client->dev, "num_regulators too large!");
                info->num_regulators = ARRAY_SIZE(ltc2978_reg_desc);
        }
#endif

        return pmbus_do_probe(client, info);
}


#ifdef CONFIG_OF
static const struct of_device_id ltc2978_of_match[] = {
        { .compatible = "lltc,ltc2972" },
        { .compatible = "lltc,ltc2974" },
        { .compatible = "lltc,ltc2975" },
        { .compatible = "lltc,ltc2977" },
        { .compatible = "lltc,ltc2978" },
        { .compatible = "lltc,ltc2979" },
        { .compatible = "lltc,ltc2980" },
        { .compatible = "lltc,ltc3880" },
        { .compatible = "lltc,ltc3882" },
        { .compatible = "lltc,ltc3883" },
        { .compatible = "lltc,ltc3884" },
        { .compatible = "lltc,ltc3886" },
        { .compatible = "lltc,ltc3887" },
        { .compatible = "lltc,ltc3889" },
        { .compatible = "lltc,ltc7880" },
        { .compatible = "lltc,ltm2987" },
        { .compatible = "lltc,ltm4664" },
        { .compatible = "lltc,ltm4675" },
        { .compatible = "lltc,ltm4676" },
        { .compatible = "lltc,ltm4677" },
        { .compatible = "lltc,ltm4678" },
        { .compatible = "lltc,ltm4680" },
        { .compatible = "lltc,ltm4686" },
        { .compatible = "lltc,ltm4700" },
        { }
};
MODULE_DEVICE_TABLE(of, ltc2978_of_match);
#endif

static struct i2c_driver ltc2978_driver = {
        .driver = {
                   .name = "ltc2978",
                   .of_match_table = of_match_ptr(ltc2978_of_match),
                   },
        .probe_new = ltc2978_probe,
        .id_table = ltc2978_id,
};

module_i2c_driver(ltc2978_driver);

MODULE_AUTHOR("Guenter Roeck");
MODULE_DESCRIPTION("PMBus driver for LTC2978 and compatible chips");
MODULE_LICENSE("GPL");
MODULE_IMPORT_NS(PMBUS);