// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Hardware monitoring driver for MPS Multi-phase Digital VR Controllers(MP2891)
 */

#include <linux/bitfield.h>
#include <linux/i2c.h>
#include <linux/module.h>
#include <linux/of_device.h>
#include "pmbus.h"

/*
 * Vender specific registers, the register MFR_SVI3_IOUT_PRT(0x65),
 * MFR_VOUT_LOOP_CTRL(0xBD), READ_PIN_EST(0x94)and READ_IIN_EST(0x95)
 * redefine the standard PMBUS register. The MFR_SVI3_IOUT_PRT(0x65)
 * is used to identify the iout scale and the MFR_VOUT_LOOP_CTRL(0xBD)
 * is used to identify the vout scale. The READ_PIN_EST(0x94) is used
 * to read input power per rail. The MP2891 does not have standard
 * READ_IIN register(0x89), the iin telemetry can be obtained through
 * the vendor redefined register READ_IIN_EST(0x95).
 */
#define MFR_VOUT_LOOP_CTRL      0xBD
#define READ_PIN_EST    0x94
#define READ_IIN_EST    0x95
#define MFR_SVI3_IOUT_PRT       0x65

#define MP2891_TEMP_LIMIT_OFFSET        40
#define MP2891_PIN_LIMIT_UINT   2
#define MP2891_IOUT_LIMIT_UINT  8
#define MP2891_IOUT_SCALE_DIV   32
#define MP2891_VOUT_SCALE_DIV   100
#define MP2891_OVUV_DELTA_SCALE 50
#define MP2891_OV_LIMIT_SCALE   20
#define MP2891_UV_LIMIT_SCALE   5

#define MP2891_PAGE_NUM 2

#define MP2891_RAIL1_FUNC       (PMBUS_HAVE_VIN | PMBUS_HAVE_VOUT | \
                                                        PMBUS_HAVE_IOUT | PMBUS_HAVE_TEMP | \
                                                        PMBUS_HAVE_POUT | PMBUS_HAVE_PIN | \
                                                        PMBUS_HAVE_IIN | PMBUS_HAVE_STATUS_VOUT | \
                                                        PMBUS_HAVE_STATUS_IOUT | \
                                                        PMBUS_HAVE_STATUS_INPUT | \
                                                        PMBUS_HAVE_STATUS_TEMP)

#define MP2891_RAIL2_FUNC       (PMBUS_HAVE_VOUT | PMBUS_HAVE_IOUT | \
                                                        PMBUS_HAVE_TEMP | PMBUS_HAVE_POUT | \
                                                        PMBUS_HAVE_PIN | PMBUS_HAVE_IIN | \
                                                        PMBUS_HAVE_STATUS_VOUT | \
                                                        PMBUS_HAVE_STATUS_IOUT | \
                                                        PMBUS_HAVE_STATUS_INPUT | \
                                                        PMBUS_HAVE_STATUS_TEMP)

struct mp2891_data {
        struct pmbus_driver_info info;
        int vout_scale[MP2891_PAGE_NUM];
        int iout_scale[MP2891_PAGE_NUM];
};

#define to_mp2891_data(x) container_of(x, struct mp2891_data, info)

/* Converts a LINEAR11 value to DIRECT format */
static u16 mp2891_reg2data_linear11(u16 word)
{
        s16 exponent;
        s32 mantissa;
        s64 val;

        exponent = ((s16)word) >> 11;
        mantissa = ((s16)((word & 0x7ff) << 5)) >> 5;
        val = mantissa;

        if (exponent >= 0)
                val <<= exponent;
        else
                val >>= -exponent;

        return val;
}

static int
mp2891_identify_vout_scale(struct i2c_client *client, struct pmbus_driver_info *info,
                           int page)
{
        struct mp2891_data *data = to_mp2891_data(info);
        int ret;

        ret = i2c_smbus_write_byte_data(client, PMBUS_PAGE, page);
        if (ret < 0)
                return ret;

        ret = i2c_smbus_read_word_data(client, MFR_VOUT_LOOP_CTRL);
        if (ret < 0)
                return ret;

        /*
         * The output voltage is equal to the READ_VOUT(0x8B) register value multiplied
         * by vout_scale.
         * Obtain vout scale from the register MFR_VOUT_LOOP_CTRL, bits 15-14,bit 13.
         * If MFR_VOUT_LOOP_CTRL[13] = 1, the vout scale is below:
         * 2.5mV/LSB
         * If MFR_VOUT_LOOP_CTRL[13] = 0, the vout scale is decided by
         * MFR_VOUT_LOOP_CTRL[15:14]:
         * 00b - 6.25mV/LSB, 01b - 5mV/LSB, 10b - 2mV/LSB, 11b - 1mV
         */
        if (ret & GENMASK(13, 13)) {
                data->vout_scale[page] = 250;
        } else {
                ret = FIELD_GET(GENMASK(15, 14), ret);
                if (ret == 0)
                        data->vout_scale[page] = 625;
                else if (ret == 1)
                        data->vout_scale[page] = 500;
                else if (ret == 2)
                        data->vout_scale[page] = 200;
                else
                        data->vout_scale[page] = 100;
        }

        return 0;
}

static int
mp2891_identify_iout_scale(struct i2c_client *client, struct pmbus_driver_info *info,
                           int page)
{
        struct mp2891_data *data = to_mp2891_data(info);
        int ret;

        ret = i2c_smbus_write_byte_data(client, PMBUS_PAGE, page);
        if (ret < 0)
                return ret;

        ret = i2c_smbus_read_word_data(client, MFR_SVI3_IOUT_PRT);
        if (ret < 0)
                return ret;

        /*
         * The output current is equal to the READ_IOUT(0x8C) register value
         * multiplied by iout_scale.
         * Obtain iout_scale from the register MFR_SVI3_IOUT_PRT[2:0].
         * The value is selected as below:
         * 000b - 1A/LSB, 001b - (1/32)A/LSB, 010b - (1/16)A/LSB,
         * 011b - (1/8)A/LSB, 100b - (1/4)A/LSB, 101b - (1/2)A/LSB
         * 110b - 1A/LSB, 111b - 2A/LSB
         */
        switch (ret & GENMASK(2, 0)) {
        case 0:
        case 6:
                data->iout_scale[page] = 32;
                break;
        case 1:
                data->iout_scale[page] = 1;
                break;
        case 2:
                data->iout_scale[page] = 2;
                break;
        case 3:
                data->iout_scale[page] = 4;
                break;
        case 4:
                data->iout_scale[page] = 8;
                break;
        case 5:
                data->iout_scale[page] = 16;
                break;
        default:
                data->iout_scale[page] = 64;
                break;
        }

        return 0;
}

static int mp2891_identify(struct i2c_client *client, struct pmbus_driver_info *info)
{
        int ret;

        /* Identify vout scale for rail 1. */
        ret = mp2891_identify_vout_scale(client, info, 0);
        if (ret < 0)
                return ret;

        /* Identify vout scale for rail 2. */
        ret = mp2891_identify_vout_scale(client, info, 1);
        if (ret < 0)
                return ret;

        /* Identify iout scale for rail 1. */
        ret = mp2891_identify_iout_scale(client, info, 0);
        if (ret < 0)
                return ret;

        /* Identify iout scale for rail 2. */
        return mp2891_identify_iout_scale(client, info, 1);
}

static int mp2891_read_byte_data(struct i2c_client *client, int page, int reg)
{
        int ret;

        switch (reg) {
        case PMBUS_VOUT_MODE:
                /*
                 * The MP2891 does not follow standard PMBus protocol completely, the
                 * PMBUS_VOUT_MODE(0x20) in MP2891 is reserved and 0x00 is always
                 * returned when the register is read. But the calculation of vout in
                 * this driver is based on direct format. As a result, the format of
                 * vout is enforced to direct.
                 */
                ret = PB_VOUT_MODE_DIRECT;
                break;
        default:
                ret = -ENODATA;
                break;
        }

        return ret;
}

static int mp2891_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 mp2891_data *data = to_mp2891_data(info);
        int ret;

        switch (reg) {
        case PMBUS_READ_VIN:
                ret = pmbus_read_word_data(client, page, phase, reg);
                if (ret < 0)
                        return ret;

                ret = ret & GENMASK(9, 0);
                break;
        case PMBUS_READ_IIN:
                /*
                 * The MP2891 does not have standard PMBUS_READ_IIN register(0x89),
                 * the iin telemetry can be obtained through the vender redefined
                 * register READ_IIN_EST(0x95). The MP2891 PMBUS_READ_IIN register
                 * is linear11 format, But the pout scale is set to 1A/Lsb(using
                 * r/m/b scale). As a result, the iin read from MP2891 should be
                 * calculated to A, then return the result to pmbus core.
                 */
                ret = pmbus_read_word_data(client, page, phase, READ_IIN_EST);
                if (ret < 0)
                        return ret;

                ret = mp2891_reg2data_linear11(ret);
                break;
        case PMBUS_READ_PIN:
                /*
                 * The MP2891 has standard PMBUS_READ_PIN register(0x97), but this
                 * is not used to read the input power per rail. The input power
                 * per rail is read through the vender redefined register
                 * READ_PIN_EST(0x94). The MP2891 PMBUS_READ_PIN register is linear11
                 * format, But the pout scale is set to 1W/Lsb(using r/m/b scale).
                 * As a result, the pin read from MP2891 should be calculated to W,
                 * then return the result to pmbus core.
                 */
                ret = pmbus_read_word_data(client, page, phase, READ_PIN_EST);
                if (ret < 0)
                        return ret;

                ret = mp2891_reg2data_linear11(ret);
                break;
        case PMBUS_READ_POUT:
                /*
                 * The MP2891 PMBUS_READ_POUT register is linear11 format, and the
                 * exponent is not a constant value. But the pout scale is set to
                 * 1W/Lsb(using r/m/b scale). As a result, the pout read from MP2891
                 * should be calculated to W, then return the result to pmbus core.
                 */
                ret = pmbus_read_word_data(client, page, phase, reg);
                if (ret < 0)
                        return ret;

                ret = mp2891_reg2data_linear11(ret);
                break;
        case PMBUS_READ_VOUT:
        case PMBUS_VOUT_UV_WARN_LIMIT:
                ret = pmbus_read_word_data(client, page, phase, reg);
                if (ret < 0)
                        return ret;

                ret = DIV_ROUND_CLOSEST(ret * data->vout_scale[page], MP2891_VOUT_SCALE_DIV);
                break;
        case PMBUS_READ_IOUT:
                ret = pmbus_read_word_data(client, page, phase, reg);
                if (ret < 0)
                        return ret;

                ret = DIV_ROUND_CLOSEST((ret & GENMASK(10, 0)) * data->iout_scale[page],
                                        MP2891_IOUT_SCALE_DIV);
                break;
        case PMBUS_OT_FAULT_LIMIT:
        case PMBUS_OT_WARN_LIMIT:
                /*
                 * The scale of MP2891 PMBUS_OT_FAULT_LIMIT and PMBUS_OT_WARN_LIMIT
                 * is 1°C/LSB and they have 40°C offset.
                 */
                ret = pmbus_read_word_data(client, page, phase, reg);
                if (ret < 0)
                        return ret;

                ret = (ret & GENMASK(7, 0)) - MP2891_TEMP_LIMIT_OFFSET;
                break;
        case PMBUS_VIN_OV_FAULT_LIMIT:
                /*
                 * The MP2891 PMBUS_VIN_OV_FAULT_LIMIT scale is 125mV/Lsb.
                 * but the vin scale is set to 31.25mV/Lsb(using r/m/b scale).
                 * As a result, the limit value should be multiplied by 4.
                 */
                ret = pmbus_read_word_data(client, page, phase, reg);
                if (ret < 0)
                        return ret;

                ret = (ret & GENMASK(7, 0)) * 4;
                break;
        case PMBUS_VOUT_UV_FAULT_LIMIT:
                ret = pmbus_read_word_data(client, page, phase, reg);
                if (ret < 0)
                        return ret;

                if (FIELD_GET(GENMASK(11, 8), ret))
                        ret = FIELD_GET(GENMASK(7, 0), ret) * MP2891_UV_LIMIT_SCALE -
                                (FIELD_GET(GENMASK(11, 8), ret) + 1) * MP2891_OVUV_DELTA_SCALE;
                else
                        ret = FIELD_GET(GENMASK(7, 0), ret) * MP2891_UV_LIMIT_SCALE;

                ret = ret < 0 ? 0 : ret;
                break;
        case PMBUS_VOUT_OV_FAULT_LIMIT:
                ret = pmbus_read_word_data(client, page, phase, reg);
                if (ret < 0)
                        return ret;

                if (FIELD_GET(GENMASK(11, 8), ret))
                        ret = FIELD_GET(GENMASK(7, 0), ret) * MP2891_OV_LIMIT_SCALE +
                                (FIELD_GET(GENMASK(11, 8), ret) + 1) * MP2891_OVUV_DELTA_SCALE;
                else
                        ret = FIELD_GET(GENMASK(7, 0), ret) * MP2891_OV_LIMIT_SCALE;
                break;
        case PMBUS_IOUT_OC_WARN_LIMIT:
        case PMBUS_IOUT_OC_FAULT_LIMIT:
                ret = pmbus_read_word_data(client, page, phase, reg);
                if (ret < 0)
                        return ret;

                ret = DIV_ROUND_CLOSEST((ret & GENMASK(7, 0)) * data->iout_scale[page] *
                                                MP2891_IOUT_LIMIT_UINT, MP2891_IOUT_SCALE_DIV);
                break;
        case PMBUS_IIN_OC_WARN_LIMIT:
                /*
                 * The scale of PMBUS_IIN_OC_WARN_LIMIT is 0.5A/Lsb, but the iin scale
                 * is set to 1A/Lsb(using r/m/b scale), so the word data should be
                 * divided by 2.
                 */
                ret = pmbus_read_word_data(client, 0, phase, reg);
                if (ret < 0)
                        return ret;

                ret = DIV_ROUND_CLOSEST((ret & GENMASK(9, 0)), 2);
                break;
        case PMBUS_PIN_OP_WARN_LIMIT:
                /*
                 * The scale of PMBUS_PIN_OP_WARN_LIMIT is 2W/Lsb, but the pin scale
                 * is set to 1W/Lsb(using r/m/b scale), so the word data should be
                 * multiplied by 2.
                 */
                ret = pmbus_read_word_data(client, 0, phase, reg);
                if (ret < 0)
                        return ret;

                ret = (ret & GENMASK(9, 0)) * MP2891_PIN_LIMIT_UINT;
                break;
        case PMBUS_READ_TEMPERATURE_1:
        case PMBUS_VIN_UV_FAULT_LIMIT:
        case PMBUS_VIN_UV_WARN_LIMIT:
                ret = -ENODATA;
                break;
        default:
                ret = -EINVAL;
                break;
        }

        return ret;
}

static int mp2891_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 mp2891_data *data = to_mp2891_data(info);
        int ret;

        switch (reg) {
        case PMBUS_VOUT_UV_WARN_LIMIT:
                ret = pmbus_write_word_data(client, page, reg,
                                            DIV_ROUND_CLOSEST(word * MP2891_VOUT_SCALE_DIV,
                                                              data->vout_scale[page]));
                break;
        case PMBUS_VOUT_UV_FAULT_LIMIT:
                /*
                 * The PMBUS_VOUT_UV_FAULT_LIMIT[7:0] is the limit value, and bit8-bit15
                 * should not be changed.
                 */
                ret = pmbus_read_word_data(client, page, 0xff, reg);
                if (ret < 0)
                        return ret;

                if (FIELD_GET(GENMASK(11, 8), ret))
                        ret = pmbus_write_word_data(client, page, reg,
                                                    (ret & ~GENMASK(7, 0)) |
                                                        FIELD_PREP(GENMASK(7, 0),
                                                                   DIV_ROUND_CLOSEST(word +
                                                        (FIELD_GET(GENMASK(11, 8), ret) + 1) *
                                                                MP2891_OVUV_DELTA_SCALE,
                                                                MP2891_UV_LIMIT_SCALE)));
                else
                        ret = pmbus_write_word_data(client, page, reg,
                                                    (ret & ~GENMASK(7, 0)) |
                                        FIELD_PREP(GENMASK(7, 0),
                                                   DIV_ROUND_CLOSEST(word,
                                                                     MP2891_UV_LIMIT_SCALE)));
                break;
        case PMBUS_VOUT_OV_FAULT_LIMIT:
                /*
                 * The PMBUS_VOUT_OV_FAULT_LIMIT[7:0] is the limit value, and bit8-bit15
                 * should not be changed.
                 */
                ret = pmbus_read_word_data(client, page, 0xff, reg);
                if (ret < 0)
                        return ret;

                if (FIELD_GET(GENMASK(11, 8), ret))
                        ret = pmbus_write_word_data(client, page, reg,
                                                    (ret & ~GENMASK(7, 0)) |
                                                        FIELD_PREP(GENMASK(7, 0),
                                                                   DIV_ROUND_CLOSEST(word -
                                                        (FIELD_GET(GENMASK(11, 8), ret) + 1) *
                                                                MP2891_OVUV_DELTA_SCALE,
                                                                MP2891_OV_LIMIT_SCALE)));
                else
                        ret = pmbus_write_word_data(client, page, reg,
                                                    (ret & ~GENMASK(7, 0)) |
                                        FIELD_PREP(GENMASK(7, 0),
                                                   DIV_ROUND_CLOSEST(word,
                                                                     MP2891_OV_LIMIT_SCALE)));
                break;
        case PMBUS_VIN_OV_FAULT_LIMIT:
                /*
                 * The PMBUS_VIN_OV_FAULT_LIMIT[7:0] is the limit value, and bit8-bit15
                 * should not be changed. The scale of PMBUS_VIN_OV_FAULT_LIMIT is 125mV/Lsb,
                 * but the vin scale is set to 31.25mV/Lsb(using r/m/b scale), so the word data
                 * should be divided by 4.
                 */
                ret = pmbus_read_word_data(client, page, 0xff, reg);
                if (ret < 0)
                        return ret;

                ret = pmbus_write_word_data(client, page, reg,
                                            (ret & ~GENMASK(7, 0)) |
                                                FIELD_PREP(GENMASK(7, 0),
                                                           DIV_ROUND_CLOSEST(word, 4)));
                break;
        case PMBUS_OT_FAULT_LIMIT:
        case PMBUS_OT_WARN_LIMIT:
                /*
                 * The scale of MP2891 PMBUS_OT_FAULT_LIMIT and PMBUS_OT_WARN_LIMIT
                 * have 40°C offset. The bit0-bit7 is the limit value, and bit8-bit15
                 * should not be changed.
                 */
                ret = pmbus_read_word_data(client, page, 0xff, reg);
                if (ret < 0)
                        return ret;

                ret = pmbus_write_word_data(client, page, reg,
                                            (ret & ~GENMASK(7, 0)) |
                                FIELD_PREP(GENMASK(7, 0), word + MP2891_TEMP_LIMIT_OFFSET));
                break;
        case PMBUS_IOUT_OC_WARN_LIMIT:
        case PMBUS_IOUT_OC_FAULT_LIMIT:
                ret = pmbus_write_word_data(client, page, reg,
                                            DIV_ROUND_CLOSEST(word * MP2891_IOUT_SCALE_DIV,
                                                              MP2891_IOUT_LIMIT_UINT *
                                                                  data->iout_scale[page]));
                break;
        case PMBUS_IIN_OC_WARN_LIMIT:
                /*
                 * The scale of PMBUS_IIN_OC_WARN_LIMIT is 0.5A/Lsb, but the iin scale
                 * is set to 1A/Lsb(using r/m/b scale), so the word data should be
                 * multiplied by 2.
                 */
                ret = pmbus_write_word_data(client, page, reg, word * 2);
                break;
        case PMBUS_PIN_OP_WARN_LIMIT:
                /*
                 * The scale of PMBUS_PIN_OP_WARN_LIMIT is 2W/Lsb, but the pin scale
                 * is set to 1W/Lsb(using r/m/b scale), so the word data should be
                 * divided by 2.
                 */
                ret = pmbus_write_word_data(client, page, reg,
                                            DIV_ROUND_CLOSEST(word, MP2891_PIN_LIMIT_UINT));
                break;
        case PMBUS_VIN_UV_FAULT_LIMIT:
        case PMBUS_VIN_UV_WARN_LIMIT:
                ret = -ENODATA;
                break;
        default:
                ret = -EINVAL;
                break;
        }

        return ret;
}

static const struct pmbus_driver_info mp2891_info = {
        .pages = MP2891_PAGE_NUM,
        .format[PSC_VOLTAGE_IN] = direct,
        .format[PSC_CURRENT_IN] = direct,
        .format[PSC_CURRENT_OUT] = direct,
        .format[PSC_TEMPERATURE] = direct,
        .format[PSC_POWER] = direct,
        .format[PSC_VOLTAGE_OUT] = direct,

        /* set vin scale 31.25mV/Lsb */
        .m[PSC_VOLTAGE_IN] = 32,
        .R[PSC_VOLTAGE_IN] = 0,
        .b[PSC_VOLTAGE_IN] = 0,

        /* set temp scale 1000m°C/Lsb */
        .m[PSC_TEMPERATURE] = 1,
        .R[PSC_TEMPERATURE] = 0,
        .b[PSC_TEMPERATURE] = 0,

        .m[PSC_CURRENT_IN] = 1,
        .R[PSC_CURRENT_IN] = 0,
        .b[PSC_CURRENT_IN] = 0,

        .m[PSC_CURRENT_OUT] = 1,
        .R[PSC_CURRENT_OUT] = 0,
        .b[PSC_CURRENT_OUT] = 0,

        .m[PSC_POWER] = 1,
        .R[PSC_POWER] = 0,
        .b[PSC_POWER] = 0,

        .m[PSC_VOLTAGE_OUT] = 1,
        .R[PSC_VOLTAGE_OUT] = 3,
        .b[PSC_VOLTAGE_OUT] = 0,

        .func[0] = MP2891_RAIL1_FUNC,
        .func[1] = MP2891_RAIL2_FUNC,
        .read_word_data = mp2891_read_word_data,
        .write_word_data = mp2891_write_word_data,
        .read_byte_data = mp2891_read_byte_data,
        .identify = mp2891_identify,
};

static int mp2891_probe(struct i2c_client *client)
{
        struct mp2891_data *data;

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

        memcpy(&data->info, &mp2891_info, sizeof(mp2891_info));

        return pmbus_do_probe(client, &data->info);
}

static const struct i2c_device_id mp2891_id[] = {
        { "mp2891" },
        { }
};
MODULE_DEVICE_TABLE(i2c, mp2891_id);

static const struct of_device_id __maybe_unused mp2891_of_match[] = {
        {.compatible = "mps,mp2891"},
        {}
};
MODULE_DEVICE_TABLE(of, mp2891_of_match);

static struct i2c_driver mp2891_driver = {
        .driver = {
                .name = "mp2891",
                .of_match_table = mp2891_of_match,
        },
        .probe = mp2891_probe,
        .id_table = mp2891_id,
};

module_i2c_driver(mp2891_driver);

MODULE_AUTHOR("Noah Wang <noahwang.wang@outlook.com>");
MODULE_DESCRIPTION("PMBus driver for MPS MP2891");
MODULE_LICENSE("GPL");
MODULE_IMPORT_NS("PMBUS");