// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Driver for MAX20710, MAX20730, MAX20734, and MAX20743 Integrated,
 * Step-Down Switching Regulators
 *
 * Copyright 2019 Google LLC.
 * Copyright 2020 Maxim Integrated
 */

#include <linux/bits.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/of_device.h>
#include <linux/pmbus.h>
#include <linux/util_macros.h>
#include "pmbus.h"

enum chips {
        max20710,
        max20730,
        max20734,
        max20743
};

struct max20730_data {
        enum chips id;
        struct pmbus_driver_info info;
        struct mutex lock;      /* Used to protect against parallel writes */
        u16 mfr_devset1;
};

#define to_max20730_data(x)  container_of(x, struct max20730_data, info)

#define MAX20730_MFR_DEVSET1    0xd2

/*
 * Convert discreet value to direct data format. Strictly speaking, all passed
 * values are constants, so we could do that calculation manually. On the
 * downside, that would make the driver more difficult to maintain, so lets
 * use this approach.
 */
static u16 val_to_direct(int v, enum pmbus_sensor_classes class,
                         const struct pmbus_driver_info *info)
{
        int R = info->R[class] - 3;     /* take milli-units into account */
        int b = info->b[class] * 1000;
        long d;

        d = v * info->m[class] + b;
        /*
         * R < 0 is true for all callers, so we don't need to bother
         * about the R > 0 case.
         */
        while (R < 0) {
                d = DIV_ROUND_CLOSEST(d, 10);
                R++;
        }
        return (u16)d;
}

static long direct_to_val(u16 w, enum pmbus_sensor_classes class,
                          const struct pmbus_driver_info *info)
{
        int R = info->R[class] - 3;
        int b = info->b[class] * 1000;
        int m = info->m[class];
        long d = (s16)w;

        if (m == 0)
                return 0;

        while (R < 0) {
                d *= 10;
                R++;
        }
        d = (d - b) / m;
        return d;
}

static u32 max_current[][5] = {
        [max20710] = { 6200, 8000, 9700, 11600 },
        [max20730] = { 13000, 16600, 20100, 23600 },
        [max20734] = { 21000, 27000, 32000, 38000 },
        [max20743] = { 18900, 24100, 29200, 34100 },
};

static int max20730_read_word_data(struct i2c_client *client, int page,
                                   int phase, int reg)
{
        const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
        const struct max20730_data *data = to_max20730_data(info);
        int ret = 0;
        u32 max_c;

        switch (reg) {
        case PMBUS_OT_FAULT_LIMIT:
                switch ((data->mfr_devset1 >> 11) & 0x3) {
                case 0x0:
                        ret = val_to_direct(150000, PSC_TEMPERATURE, info);
                        break;
                case 0x1:
                        ret = val_to_direct(130000, PSC_TEMPERATURE, info);
                        break;
                default:
                        ret = -ENODATA;
                        break;
                }
                break;
        case PMBUS_IOUT_OC_FAULT_LIMIT:
                max_c = max_current[data->id][(data->mfr_devset1 >> 5) & 0x3];
                ret = val_to_direct(max_c, PSC_CURRENT_OUT, info);
                break;
        default:
                ret = -ENODATA;
                break;
        }
        return ret;
}

static int max20730_write_word_data(struct i2c_client *client, int page,
                                    int reg, u16 word)
{
        struct pmbus_driver_info *info;
        struct max20730_data *data;
        u16 devset1;
        int ret = 0;
        int idx;

        info = (struct pmbus_driver_info *)pmbus_get_driver_info(client);
        data = to_max20730_data(info);

        mutex_lock(&data->lock);
        devset1 = data->mfr_devset1;

        switch (reg) {
        case PMBUS_OT_FAULT_LIMIT:
                devset1 &= ~(BIT(11) | BIT(12));
                if (direct_to_val(word, PSC_TEMPERATURE, info) < 140000)
                        devset1 |= BIT(11);
                break;
        case PMBUS_IOUT_OC_FAULT_LIMIT:
                devset1 &= ~(BIT(5) | BIT(6));

                idx = find_closest(direct_to_val(word, PSC_CURRENT_OUT, info),
                                   max_current[data->id], 4);
                devset1 |= (idx << 5);
                break;
        default:
                ret = -ENODATA;
                break;
        }

        if (!ret && devset1 != data->mfr_devset1) {
                ret = i2c_smbus_write_word_data(client, MAX20730_MFR_DEVSET1,
                                                devset1);
                if (!ret) {
                        data->mfr_devset1 = devset1;
                        pmbus_clear_cache(client);
                }
        }
        mutex_unlock(&data->lock);
        return ret;
}

static const struct pmbus_driver_info max20730_info[] = {
        [max20710] = {
                .pages = 1,
                .read_word_data = max20730_read_word_data,
                .write_word_data = max20730_write_word_data,

                /* Source : Maxim AN6140 and AN6042 */
                .format[PSC_TEMPERATURE] = direct,
                .m[PSC_TEMPERATURE] = 21,
                .b[PSC_TEMPERATURE] = 5887,
                .R[PSC_TEMPERATURE] = -1,

                .format[PSC_VOLTAGE_IN] = direct,
                .m[PSC_VOLTAGE_IN] = 3609,
                .b[PSC_VOLTAGE_IN] = 0,
                .R[PSC_VOLTAGE_IN] = -2,

                .format[PSC_CURRENT_OUT] = direct,
                .m[PSC_CURRENT_OUT] = 153,
                .b[PSC_CURRENT_OUT] = 4976,
                .R[PSC_CURRENT_OUT] = -1,

                .format[PSC_VOLTAGE_OUT] = linear,

                .func[0] = PMBUS_HAVE_VIN |
                        PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT |
                        PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT |
                        PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP |
                        PMBUS_HAVE_STATUS_INPUT,
        },
        [max20730] = {
                .pages = 1,
                .read_word_data = max20730_read_word_data,
                .write_word_data = max20730_write_word_data,

                /* Source : Maxim AN6042 */
                .format[PSC_TEMPERATURE] = direct,
                .m[PSC_TEMPERATURE] = 21,
                .b[PSC_TEMPERATURE] = 5887,
                .R[PSC_TEMPERATURE] = -1,

                .format[PSC_VOLTAGE_IN] = direct,
                .m[PSC_VOLTAGE_IN] = 3609,
                .b[PSC_VOLTAGE_IN] = 0,
                .R[PSC_VOLTAGE_IN] = -2,

                /*
                 * Values in the datasheet are adjusted for temperature and
                 * for the relationship between Vin and Vout.
                 * Unfortunately, the data sheet suggests that Vout measurement
                 * may be scaled with a resistor array. This is indeed the case
                 * at least on the evaulation boards. As a result, any in-driver
                 * adjustments would either be wrong or require elaborate means
                 * to configure the scaling. Instead of doing that, just report
                 * raw values and let userspace handle adjustments.
                 */
                .format[PSC_CURRENT_OUT] = direct,
                .m[PSC_CURRENT_OUT] = 153,
                .b[PSC_CURRENT_OUT] = 4976,
                .R[PSC_CURRENT_OUT] = -1,

                .format[PSC_VOLTAGE_OUT] = linear,

                .func[0] = PMBUS_HAVE_VIN |
                        PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT |
                        PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT |
                        PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP |
                        PMBUS_HAVE_STATUS_INPUT,
        },
        [max20734] = {
                .pages = 1,
                .read_word_data = max20730_read_word_data,
                .write_word_data = max20730_write_word_data,

                /* Source : Maxim AN6209 */
                .format[PSC_TEMPERATURE] = direct,
                .m[PSC_TEMPERATURE] = 21,
                .b[PSC_TEMPERATURE] = 5887,
                .R[PSC_TEMPERATURE] = -1,

                .format[PSC_VOLTAGE_IN] = direct,
                .m[PSC_VOLTAGE_IN] = 3592,
                .b[PSC_VOLTAGE_IN] = 0,
                .R[PSC_VOLTAGE_IN] = -2,

                .format[PSC_CURRENT_OUT] = direct,
                .m[PSC_CURRENT_OUT] = 111,
                .b[PSC_CURRENT_OUT] = 3461,
                .R[PSC_CURRENT_OUT] = -1,

                .format[PSC_VOLTAGE_OUT] = linear,

                .func[0] = PMBUS_HAVE_VIN |
                        PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT |
                        PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT |
                        PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP |
                        PMBUS_HAVE_STATUS_INPUT,
        },
        [max20743] = {
                .pages = 1,
                .read_word_data = max20730_read_word_data,
                .write_word_data = max20730_write_word_data,

                /* Source : Maxim AN6042 */
                .format[PSC_TEMPERATURE] = direct,
                .m[PSC_TEMPERATURE] = 21,
                .b[PSC_TEMPERATURE] = 5887,
                .R[PSC_TEMPERATURE] = -1,

                .format[PSC_VOLTAGE_IN] = direct,
                .m[PSC_VOLTAGE_IN] = 3597,
                .b[PSC_VOLTAGE_IN] = 0,
                .R[PSC_VOLTAGE_IN] = -2,

                .format[PSC_CURRENT_OUT] = direct,
                .m[PSC_CURRENT_OUT] = 95,
                .b[PSC_CURRENT_OUT] = 5014,
                .R[PSC_CURRENT_OUT] = -1,

                .format[PSC_VOLTAGE_OUT] = linear,

                .func[0] = PMBUS_HAVE_VIN |
                        PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT |
                        PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT |
                        PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP |
                        PMBUS_HAVE_STATUS_INPUT,
        },
};

static int max20730_probe(struct i2c_client *client,
                          const struct i2c_device_id *id)
{
        struct device *dev = &client->dev;
        u8 buf[I2C_SMBUS_BLOCK_MAX + 1];
        struct max20730_data *data;
        enum chips chip_id;
        int ret;

        if (!i2c_check_functionality(client->adapter,
                                     I2C_FUNC_SMBUS_READ_BYTE_DATA |
                                     I2C_FUNC_SMBUS_READ_WORD_DATA |
                                     I2C_FUNC_SMBUS_BLOCK_DATA))
                return -ENODEV;

        ret = i2c_smbus_read_block_data(client, PMBUS_MFR_ID, buf);
        if (ret < 0) {
                dev_err(&client->dev, "Failed to read Manufacturer ID\n");
                return ret;
        }
        if (ret != 5 || strncmp(buf, "MAXIM", 5)) {
                buf[ret] = '\0';
                dev_err(dev, "Unsupported Manufacturer ID '%s'\n", buf);
                return -ENODEV;
        }

        /*
         * The chips support reading PMBUS_MFR_MODEL. On both MAX20730
         * and MAX20734, reading it returns M20743. Presumably that is
         * the reason why the command is not documented. Unfortunately,
         * that means that there is no reliable means to detect the chip.
         * However, we can at least detect the chip series. Compare
         * the returned value against 'M20743' and bail out if there is
         * a mismatch. If that doesn't work for all chips, we may have
         * to remove this check.
         */
        ret = i2c_smbus_read_block_data(client, PMBUS_MFR_MODEL, buf);
        if (ret < 0) {
                dev_err(dev, "Failed to read Manufacturer Model\n");
                return ret;
        }
        if (ret != 6 || strncmp(buf, "M20743", 6)) {
                buf[ret] = '\0';
                dev_err(dev, "Unsupported Manufacturer Model '%s'\n", buf);
                return -ENODEV;
        }

        ret = i2c_smbus_read_block_data(client, PMBUS_MFR_REVISION, buf);
        if (ret < 0) {
                dev_err(dev, "Failed to read Manufacturer Revision\n");
                return ret;
        }
        if (ret != 1 || buf[0] != 'F') {
                buf[ret] = '\0';
                dev_err(dev, "Unsupported Manufacturer Revision '%s'\n", buf);
                return -ENODEV;
        }

        if (client->dev.of_node)
                chip_id = (enum chips)of_device_get_match_data(dev);
        else
                chip_id = id->driver_data;

        data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
        if (!data)
                return -ENOMEM;
        data->id = chip_id;
        mutex_init(&data->lock);
        memcpy(&data->info, &max20730_info[chip_id], sizeof(data->info));

        ret = i2c_smbus_read_word_data(client, MAX20730_MFR_DEVSET1);
        if (ret < 0)
                return ret;
        data->mfr_devset1 = ret;

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

static const struct i2c_device_id max20730_id[] = {
        { "max20710", max20710 },
        { "max20730", max20730 },
        { "max20734", max20734 },
        { "max20743", max20743 },
        { },
};

MODULE_DEVICE_TABLE(i2c, max20730_id);

static const struct of_device_id max20730_of_match[] = {
        { .compatible = "maxim,max20710", .data = (void *)max20710 },
        { .compatible = "maxim,max20730", .data = (void *)max20730 },
        { .compatible = "maxim,max20734", .data = (void *)max20734 },
        { .compatible = "maxim,max20743", .data = (void *)max20743 },
        { },
};

MODULE_DEVICE_TABLE(of, max20730_of_match);

static struct i2c_driver max20730_driver = {
        .driver = {
                .name = "max20730",
                .of_match_table = max20730_of_match,
        },
        .probe = max20730_probe,
        .remove = pmbus_do_remove,
        .id_table = max20730_id,
};

module_i2c_driver(max20730_driver);

MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
MODULE_DESCRIPTION("PMBus driver for Maxim MAX20710 / MAX20730 / MAX20734 / MAX20743");
MODULE_LICENSE("GPL");