// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Hardware monitoring driver for MPS Single-phase Digital VR Controllers(MP9945)
 */

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

#define MFR_VR_MULTI_CONFIG_R1  0x08
#define MFR_SVID_CFG_R1         0xBD

/* VOUT_MODE register values */
#define VOUT_MODE_LINEAR16      0x17
#define VOUT_MODE_VID           0x21
#define VOUT_MODE_DIRECT        0x40

#define MP9945_PAGE_NUM         1

#define MP9945_RAIL1_FUNC       (PMBUS_HAVE_VIN | PMBUS_HAVE_VOUT | \
                                PMBUS_HAVE_IIN | PMBUS_HAVE_IOUT | \
                                PMBUS_HAVE_PIN | PMBUS_HAVE_POUT | \
                                PMBUS_HAVE_TEMP | \
                                PMBUS_HAVE_STATUS_VOUT | \
                                PMBUS_HAVE_STATUS_IOUT | \
                                PMBUS_HAVE_STATUS_TEMP | \
                                PMBUS_HAVE_STATUS_INPUT)

enum mp9945_vout_mode {
        MP9945_VOUT_MODE_VID,
        MP9945_VOUT_MODE_DIRECT,
        MP9945_VOUT_MODE_LINEAR16,
};

struct mp9945_data {
        struct pmbus_driver_info info;
        enum mp9945_vout_mode vout_mode;
        int vid_resolution;
        int vid_offset;
};

#define to_mp9945_data(x) container_of(x, struct mp9945_data, info)

static int mp9945_read_vout(struct i2c_client *client, struct mp9945_data *data)
{
        int ret;

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

        ret &= GENMASK(11, 0);

        switch (data->vout_mode) {
        case MP9945_VOUT_MODE_VID:
                if (ret > 0)
                        ret = (ret + data->vid_offset) * data->vid_resolution;
                break;
        case MP9945_VOUT_MODE_DIRECT:
                break;
        case MP9945_VOUT_MODE_LINEAR16:
                /* LSB: 1000 * 2^-9 (mV) */
                ret = DIV_ROUND_CLOSEST(ret * 125, 64);
                break;
        default:
                return -ENODEV;
        }

        return ret;
}

static int mp9945_read_byte_data(struct i2c_client *client, int page, int reg)
{
        int ret;

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

        switch (reg) {
        case PMBUS_VOUT_MODE:
                /*
                 * Override VOUT_MODE to DIRECT as the driver handles custom
                 * VOUT format conversions internally.
                 */
                return PB_VOUT_MODE_DIRECT;
        default:
                return -ENODATA;
        }
}

static int mp9945_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 mp9945_data *data = to_mp9945_data(info);
        int ret;

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

        switch (reg) {
        case PMBUS_READ_VOUT:
                ret = mp9945_read_vout(client, data);
                break;
        case PMBUS_VOUT_OV_FAULT_LIMIT:
        case PMBUS_VOUT_UV_FAULT_LIMIT:
                ret = i2c_smbus_read_word_data(client, reg);
                if (ret < 0)
                        return ret;

                /* LSB: 1.95 (mV) */
                ret = DIV_ROUND_CLOSEST((ret & GENMASK(11, 0)) * 39, 20);
                break;
        case PMBUS_VOUT_UV_WARN_LIMIT:
                ret = i2c_smbus_read_word_data(client, reg);
                if (ret < 0)
                        return ret;

                ret &= GENMASK(9, 0);
                if (ret > 0)
                        ret = (ret + data->vid_offset) * data->vid_resolution;
                break;
        default:
                ret = -ENODATA;
                break;
        }

        return ret;
}

static int mp9945_identify(struct i2c_client *client,
                           struct pmbus_driver_info *info)
{
        struct mp9945_data *data = to_mp9945_data(info);
        int ret;

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

        switch (ret) {
        case VOUT_MODE_LINEAR16:
                data->vout_mode = MP9945_VOUT_MODE_LINEAR16;
                break;
        case VOUT_MODE_VID:
                data->vout_mode = MP9945_VOUT_MODE_VID;
                break;
        case VOUT_MODE_DIRECT:
                data->vout_mode = MP9945_VOUT_MODE_DIRECT;
                break;
        default:
                return -ENODEV;
        }

        ret = i2c_smbus_write_byte_data(client, PMBUS_PAGE, 3);
        if (ret < 0)
                return ret;

        ret = i2c_smbus_read_word_data(client, MFR_VR_MULTI_CONFIG_R1);
        if (ret < 0)
                return ret;

        data->vid_resolution = (FIELD_GET(BIT(2), ret)) ? 5 : 10;

        ret = i2c_smbus_read_word_data(client, MFR_SVID_CFG_R1);
        if (ret < 0)
                return ret;

        data->vid_offset = (FIELD_GET(BIT(15), ret)) ? 19 : 49;

        return i2c_smbus_write_byte_data(client, PMBUS_PAGE, 0);
}

static struct pmbus_driver_info mp9945_info = {
        .pages = MP9945_PAGE_NUM,
        .format[PSC_VOLTAGE_IN] = linear,
        .format[PSC_VOLTAGE_OUT] = direct,
        .format[PSC_CURRENT_IN] = linear,
        .format[PSC_CURRENT_OUT] = linear,
        .format[PSC_POWER] = linear,
        .format[PSC_TEMPERATURE] = linear,
        .m[PSC_VOLTAGE_OUT] = 1,
        .R[PSC_VOLTAGE_OUT] = 3,
        .b[PSC_VOLTAGE_OUT] = 0,
        .func[0] = MP9945_RAIL1_FUNC,
        .read_word_data = mp9945_read_word_data,
        .read_byte_data = mp9945_read_byte_data,
        .identify = mp9945_identify,
};

static int mp9945_probe(struct i2c_client *client)
{
        struct mp9945_data *data;
        int ret;

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

        memcpy(&data->info, &mp9945_info, sizeof(mp9945_info));

        /*
         * Set page 0 before probe. The core reads paged registers which are
         * only on page 0 for this device.
         */
        ret = i2c_smbus_write_byte_data(client, PMBUS_PAGE, 0);
        if (ret < 0)
                return ret;

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

static const struct i2c_device_id mp9945_id[] = {
        {"mp9945"},
        {}
};
MODULE_DEVICE_TABLE(i2c, mp9945_id);

static const struct of_device_id __maybe_unused mp9945_of_match[] = {
        {.compatible = "mps,mp9945"},
        {}
};
MODULE_DEVICE_TABLE(of, mp9945_of_match);

static struct i2c_driver mp9945_driver = {
        .driver = {
                .name = "mp9945",
                .of_match_table = of_match_ptr(mp9945_of_match),
        },
        .probe = mp9945_probe,
        .id_table = mp9945_id,
};

module_i2c_driver(mp9945_driver);

MODULE_AUTHOR("Cosmo Chou <chou.cosmo@gmail.com>");
MODULE_DESCRIPTION("PMBus driver for MPS MP9945");
MODULE_LICENSE("GPL");
MODULE_IMPORT_NS("PMBUS");