// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Hardware monitoring driver for MPS Multi-phase Digital VR Controllers(MP2925)
 */

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

/*
 * Vender specific register MFR_VR_MULTI_CONFIG(0x08).
 * This register is used to obtain vid scale.
 */
#define MFR_VR_MULTI_CONFIG     0x08

#define MP2925_VOUT_DIV 512
#define MP2925_VOUT_OVUV_UINT   195
#define MP2925_VOUT_OVUV_DIV    100

#define MP2925_PAGE_NUM 2

#define MP2925_RAIL1_FUNC       (PMBUS_HAVE_VIN | PMBUS_HAVE_PIN | \
                                                         PMBUS_HAVE_VOUT | PMBUS_HAVE_IOUT | \
                                                         PMBUS_HAVE_POUT | PMBUS_HAVE_TEMP | \
                                                         PMBUS_HAVE_STATUS_VOUT | \
                                                         PMBUS_HAVE_STATUS_IOUT | \
                                                         PMBUS_HAVE_STATUS_TEMP | \
                                                         PMBUS_HAVE_STATUS_INPUT)

#define MP2925_RAIL2_FUNC       (PMBUS_HAVE_PIN | PMBUS_HAVE_VOUT | \
                                                         PMBUS_HAVE_IOUT | PMBUS_HAVE_POUT | \
                                                         PMBUS_HAVE_TEMP | PMBUS_HAVE_IIN | \
                                                         PMBUS_HAVE_STATUS_VOUT | \
                                                         PMBUS_HAVE_STATUS_IOUT | \
                                                         PMBUS_HAVE_STATUS_TEMP | \
                                                         PMBUS_HAVE_STATUS_INPUT)

struct mp2925_data {
        struct pmbus_driver_info info;
        int vout_scale[MP2925_PAGE_NUM];
        int vid_offset[MP2925_PAGE_NUM];
};

#define to_mp2925_data(x) container_of(x, struct mp2925_data, info)

static u16 mp2925_linear_exp_transfer(u16 word, u16 expect_exponent)
{
        s16 exponent, mantissa, target_exponent;

        exponent = ((s16)word) >> 11;
        mantissa = ((s16)((word & 0x7ff) << 5)) >> 5;
        target_exponent = (s16)((expect_exponent & 0x1f) << 11) >> 11;

        if (exponent > target_exponent)
                mantissa = mantissa << (exponent - target_exponent);
        else
                mantissa = mantissa >> (target_exponent - exponent);

        return (mantissa & 0x7ff) | ((expect_exponent << 11) & 0xf800);
}

static int mp2925_read_byte_data(struct i2c_client *client, int page, int reg)
{
        int ret;

        switch (reg) {
        case PMBUS_VOUT_MODE:
                /*
                 * The MP2925 does not follow standard PMBus protocol completely,
                 * and 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 mp2925_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 mp2925_data *data = to_mp2925_data(info);
        int ret;

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

                /*
                 * In vid mode, the MP2925 vout telemetry has 49 vid step offset, but
                 * PMBUS_VOUT_OV_FAULT_LIMIT and PMBUS_VOUT_UV_FAULT_LIMIT do not take
                 * this into consideration, its resolution is 1.95mV/LSB, as a result,
                 * format[PSC_VOLTAGE_OUT] can not be set to vid directly. Adding extra
                 * vid_offset variable for vout telemetry.
                 */
                ret = DIV_ROUND_CLOSEST(((ret & GENMASK(11, 0)) + data->vid_offset[page]) *
                                        data->vout_scale[page], MP2925_VOUT_DIV);
                break;
        case PMBUS_VOUT_OV_FAULT_LIMIT:
        case PMBUS_VOUT_UV_FAULT_LIMIT:
                ret = pmbus_read_word_data(client, page, phase, reg);
                if (ret < 0)
                        return ret;

                ret = DIV_ROUND_CLOSEST((ret & GENMASK(11, 0)) * MP2925_VOUT_OVUV_UINT,
                                        MP2925_VOUT_OVUV_DIV);
                break;
        case PMBUS_STATUS_WORD:
        case PMBUS_READ_VIN:
        case PMBUS_READ_IOUT:
        case PMBUS_READ_POUT:
        case PMBUS_READ_PIN:
        case PMBUS_READ_IIN:
        case PMBUS_READ_TEMPERATURE_1:
        case PMBUS_VIN_OV_FAULT_LIMIT:
        case PMBUS_VIN_OV_WARN_LIMIT:
        case PMBUS_VIN_UV_WARN_LIMIT:
        case PMBUS_VIN_UV_FAULT_LIMIT:
        case PMBUS_IOUT_OC_FAULT_LIMIT:
        case PMBUS_IOUT_OC_WARN_LIMIT:
        case PMBUS_OT_FAULT_LIMIT:
        case PMBUS_OT_WARN_LIMIT:
                ret = -ENODATA;
                break;
        default:
                ret = -EINVAL;
                break;
        }

        return ret;
}

static int mp2925_write_word_data(struct i2c_client *client, int page, int reg,
                                  u16 word)
{
        int ret;

        switch (reg) {
        case PMBUS_VIN_OV_FAULT_LIMIT:
        case PMBUS_VIN_OV_WARN_LIMIT:
        case PMBUS_VIN_UV_WARN_LIMIT:
        case PMBUS_VIN_UV_FAULT_LIMIT:
                /*
                 * The PMBUS_VIN_OV_FAULT_LIMIT, PMBUS_VIN_OV_WARN_LIMIT,
                 * PMBUS_VIN_UV_WARN_LIMIT and PMBUS_VIN_UV_FAULT_LIMIT
                 * of MP2925 is linear11 format, and the exponent is a
                 * constant value(5'b11100)， so the exponent of word
                 * parameter should be converted to 5'b11100(0x1C).
                 */
                ret = pmbus_write_word_data(client, page, reg,
                                            mp2925_linear_exp_transfer(word, 0x1C));
                break;
        case PMBUS_VOUT_OV_FAULT_LIMIT:
        case PMBUS_VOUT_UV_FAULT_LIMIT:
                /*
                 * The bit0-bit11 is the limit value, and bit12-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(11, 0)) |
                                FIELD_PREP(GENMASK(11, 0),
                                           DIV_ROUND_CLOSEST(word * MP2925_VOUT_OVUV_DIV,
                                                             MP2925_VOUT_OVUV_UINT)));
                break;
        case PMBUS_OT_FAULT_LIMIT:
        case PMBUS_OT_WARN_LIMIT:
                /*
                 * The PMBUS_OT_FAULT_LIMIT and PMBUS_OT_WARN_LIMIT of
                 * MP2925 is linear11 format, and the exponent is a
                 * constant value(5'b00000), so the exponent of word
                 * parameter should be converted to 5'b00000.
                 */
                ret = pmbus_write_word_data(client, page, reg,
                                            mp2925_linear_exp_transfer(word, 0x00));
                break;
        case PMBUS_IOUT_OC_FAULT_LIMIT:
        case PMBUS_IOUT_OC_WARN_LIMIT:
                /*
                 * The PMBUS_IOUT_OC_FAULT_LIMIT and PMBUS_IOUT_OC_WARN_LIMIT
                 * of MP2925 is linear11 format, and the exponent can 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,
                                            mp2925_linear_exp_transfer(word,
                                                                       FIELD_GET(GENMASK(15, 11),
                                                                                 ret)));
                break;
        default:
                ret = -EINVAL;
                break;
        }

        return ret;
}

static int
mp2925_identify_vout_scale(struct i2c_client *client, struct pmbus_driver_info *info,
                           int page)
{
        struct mp2925_data *data = to_mp2925_data(info);
        int ret;

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

        ret = i2c_smbus_read_byte_data(client, PMBUS_VOUT_MODE);
        if (ret < 0)
                return ret;

        if (FIELD_GET(GENMASK(5, 5), ret)) {
                ret = i2c_smbus_write_byte_data(client, PMBUS_PAGE,
                                                page == 0 ? 3 : 4);
                if (ret < 0)
                        return ret;

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

                if (FIELD_GET(GENMASK(5, 5), ret))
                        data->vout_scale[page] = 2560;
                else
                        data->vout_scale[page] = 5120;

                /*
                 * In vid mode, the MP2925 vout telemetry has 49 vid step offset, but
                 * PMBUS_VOUT_OV_FAULT_LIMIT and PMBUS_VOUT_UV_FAULT_LIMIT do not take
                 * this into consideration, its resolution is 1.95mV/LSB, as a result,
                 * format[PSC_VOLTAGE_OUT] can not be set to vid directly. Adding extra
                 * vid_offset variable for vout telemetry.
                 */
                data->vid_offset[page] = 49;
        } else if (FIELD_GET(GENMASK(4, 4), ret)) {
                data->vout_scale[page] = 1;
                data->vid_offset[page] = 0;
        } else {
                data->vout_scale[page] = 512;
                data->vid_offset[page] = 0;
        }

        return 0;
}

static int mp2925_identify(struct i2c_client *client, struct pmbus_driver_info *info)
{
        int ret;

        ret = mp2925_identify_vout_scale(client, info, 0);
        if (ret < 0)
                return ret;

        return mp2925_identify_vout_scale(client, info, 1);
}

static const struct pmbus_driver_info mp2925_info = {
        .pages = MP2925_PAGE_NUM,
        .format[PSC_VOLTAGE_IN] = linear,
        .format[PSC_CURRENT_IN] = linear,
        .format[PSC_CURRENT_OUT] = linear,
        .format[PSC_POWER] = linear,
        .format[PSC_TEMPERATURE] = linear,
        .format[PSC_VOLTAGE_OUT] = direct,

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

        .func[0] = MP2925_RAIL1_FUNC,
        .func[1] = MP2925_RAIL2_FUNC,
        .read_word_data = mp2925_read_word_data,
        .read_byte_data = mp2925_read_byte_data,
        .write_word_data = mp2925_write_word_data,
        .identify = mp2925_identify,
};

static int mp2925_probe(struct i2c_client *client)
{
        struct mp2925_data *data;

        data = devm_kzalloc(&client->dev, sizeof(struct mp2925_data), GFP_KERNEL);
        if (!data)
                return -ENOMEM;

        memcpy(&data->info, &mp2925_info, sizeof(mp2925_info));

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

static const struct i2c_device_id mp2925_id[] = {
        {"mp2925"},
        {"mp2929"},
        {}
};
MODULE_DEVICE_TABLE(i2c, mp2925_id);

static const struct of_device_id __maybe_unused mp2925_of_match[] = {
        {.compatible = "mps,mp2925"},
        {.compatible = "mps,mp2929"},
        {}
};
MODULE_DEVICE_TABLE(of, mp2925_of_match);

static struct i2c_driver mp2925_driver = {
        .driver = {
                .name = "mp2925",
                .of_match_table = mp2925_of_match,
        },
        .probe = mp2925_probe,
        .id_table = mp2925_id,
};

module_i2c_driver(mp2925_driver);

MODULE_AUTHOR("Wensheng Wang <wenswang@yeah.net>");
MODULE_DESCRIPTION("PMBus driver for MPS MP2925");
MODULE_LICENSE("GPL");
MODULE_IMPORT_NS("PMBUS");