// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Hardware monitoring driver for MPS Multi-phase Digital VR Controllers(MP2993)
 */

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

#define MP2993_VOUT_OVUV_UINT   125
#define MP2993_VOUT_OVUV_DIV    64
#define MP2993_VIN_LIMIT_UINT   1
#define MP2993_VIN_LIMIT_DIV    8
#define MP2993_READ_VIN_UINT    1
#define MP2993_READ_VIN_DIV     32

#define MP2993_PAGE_NUM 2

#define MP2993_RAIL1_FUNC       (PMBUS_HAVE_VIN | PMBUS_HAVE_VOUT | \
                                                        PMBUS_HAVE_IOUT | PMBUS_HAVE_POUT | \
                                                        PMBUS_HAVE_TEMP | PMBUS_HAVE_PIN | \
                                                        PMBUS_HAVE_IIN | \
                                                        PMBUS_HAVE_STATUS_VOUT | \
                                                        PMBUS_HAVE_STATUS_IOUT | \
                                                        PMBUS_HAVE_STATUS_TEMP | \
                                                        PMBUS_HAVE_STATUS_INPUT)

#define MP2993_RAIL2_FUNC       (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)

/* Converts a linear11 data exponent to a specified value */
static u16 mp2993_linear11_exponent_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
mp2993_set_vout_format(struct i2c_client *client, int page, int format)
{
        int ret;

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

        return i2c_smbus_write_byte_data(client, PMBUS_VOUT_MODE, format);
}

static int mp2993_identify(struct i2c_client *client, struct pmbus_driver_info *info)
{
        int ret;

        /* Set vout to direct format for rail1. */
        ret = mp2993_set_vout_format(client, 0, PB_VOUT_MODE_DIRECT);
        if (ret < 0)
                return ret;

        /* Set vout to direct format for rail2. */
        return mp2993_set_vout_format(client, 1, PB_VOUT_MODE_DIRECT);
}

static int mp2993_read_word_data(struct i2c_client *client, int page, int phase,
                                 int reg)
{
        int ret;

        switch (reg) {
        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 * MP2993_VOUT_OVUV_UINT, MP2993_VOUT_OVUV_DIV);
                break;
        case PMBUS_OT_FAULT_LIMIT:
        case PMBUS_OT_WARN_LIMIT:
                /*
                 * The MP2993 ot fault limit value and ot warn limit value
                 * per rail are always the same, so only PMBUS_OT_FAULT_LIMIT
                 * and PMBUS_OT_WARN_LIMIT register in page 0 are defined to
                 * indicates the limit value.
                 */
                ret = pmbus_read_word_data(client, 0, phase, reg);
                break;
        case PMBUS_READ_VIN:
                /* The MP2993 vin scale is (1/32V)/Lsb */
                ret = pmbus_read_word_data(client, page, phase, reg);
                if (ret < 0)
                        return ret;

                ret = DIV_ROUND_CLOSEST((ret & GENMASK(9, 0)) * MP2993_READ_VIN_UINT,
                                        MP2993_READ_VIN_DIV);
                break;
        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 MP2993 vin limit scale is (1/8V)/Lsb */
                ret = pmbus_read_word_data(client, page, phase, reg);
                if (ret < 0)
                        return ret;

                ret = DIV_ROUND_CLOSEST((ret & GENMASK(7, 0)) * MP2993_VIN_LIMIT_UINT,
                                        MP2993_VIN_LIMIT_DIV);
                break;
        case PMBUS_READ_IOUT:
        case PMBUS_READ_IIN:
        case PMBUS_IIN_OC_WARN_LIMIT:
        case PMBUS_IOUT_OC_FAULT_LIMIT:
        case PMBUS_IOUT_OC_WARN_LIMIT:
        case PMBUS_READ_VOUT:
        case PMBUS_READ_PIN:
        case PMBUS_READ_POUT:
        case PMBUS_READ_TEMPERATURE_1:
                ret = -ENODATA;
                break;
        default:
                ret = -EINVAL;
                break;
        }

        return ret;
}

static int mp2993_write_word_data(struct i2c_client *client, int page, int reg,
                                  u16 word)
{
        int ret;

        switch (reg) {
        case PMBUS_VOUT_OV_FAULT_LIMIT:
        case PMBUS_VOUT_UV_FAULT_LIMIT:
                ret = DIV_ROUND_CLOSEST(word * MP2993_VOUT_OVUV_DIV, MP2993_VOUT_OVUV_UINT);
                ret = pmbus_write_word_data(client, 0, reg, ret);
                break;
        case PMBUS_OT_FAULT_LIMIT:
        case PMBUS_OT_WARN_LIMIT:
                /*
                 * The MP2993 ot fault limit value and ot warn limit value
                 * per rail are always the same, so only PMBUS_OT_FAULT_LIMIT
                 * and PMBUS_OT_WARN_LIMIT register in page 0 are defined to
                 * config the ot limit value.
                 */
                ret = pmbus_write_word_data(client, 0, reg, word);
                break;
        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 MP2993 vin limit scale is (1/8V)/Lsb */
                ret = pmbus_write_word_data(client, 0, reg,
                                            DIV_ROUND_CLOSEST(word * MP2993_VIN_LIMIT_DIV,
                                                              MP2993_VIN_LIMIT_UINT));
                break;
        case PMBUS_IIN_OC_WARN_LIMIT:
                /*
                 * The PMBUS_IIN_OC_WARN_LIMIT of MP2993 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,
                                            mp2993_linear11_exponent_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 MP2993 can be regarded as linear11 format, and the
                 * exponent is a 5'b00001 or 5'b00000. To ensure a larger
                 * range of limit value, so the exponent of word parameter
                 * should be converted to 5'b00001.
                 */
                ret = pmbus_write_word_data(client, page, reg,
                                            mp2993_linear11_exponent_transfer(word, 0x01));
                break;
        default:
                ret = -EINVAL;
                break;
        }

        return ret;
}

static struct pmbus_driver_info mp2993_info = {
        .pages = MP2993_PAGE_NUM,
        .format[PSC_VOLTAGE_IN] = direct,
        .format[PSC_CURRENT_IN] = linear,
        .format[PSC_CURRENT_OUT] = linear,
        .format[PSC_TEMPERATURE] = direct,
        .format[PSC_POWER] = linear,
        .format[PSC_VOLTAGE_OUT] = direct,

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

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

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

        .func[0] = MP2993_RAIL1_FUNC,
        .func[1] = MP2993_RAIL2_FUNC,
        .read_word_data = mp2993_read_word_data,
        .write_word_data = mp2993_write_word_data,
        .identify = mp2993_identify,
};

static int mp2993_probe(struct i2c_client *client)
{
        return pmbus_do_probe(client, &mp2993_info);
}

static const struct i2c_device_id mp2993_id[] = {
        { "mp2993" },
        { }
};
MODULE_DEVICE_TABLE(i2c, mp2993_id);

static const struct of_device_id __maybe_unused mp2993_of_match[] = {
        {.compatible = "mps,mp2993"},
        {}
};
MODULE_DEVICE_TABLE(of, mp2993_of_match);

static struct i2c_driver mp2993_driver = {
        .driver = {
                .name = "mp2993",
                .of_match_table = mp2993_of_match,
        },
        .probe = mp2993_probe,
        .id_table = mp2993_id,
};

module_i2c_driver(mp2993_driver);

MODULE_AUTHOR("Noah Wang <noahwang.wang@outlook.com>");
MODULE_DESCRIPTION("PMBus driver for MPS MP2993");
MODULE_LICENSE("GPL");
MODULE_IMPORT_NS("PMBUS");