// SPDX-License-Identifier: GPL-2.0+
/*
 * Hardware monitoring driver for Infineon TDA38640
 *
 * Copyright (c) 2023 9elements GmbH
 *
 */

#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/regulator/driver.h>
#include "pmbus.h"

static const struct regulator_desc __maybe_unused tda38640_reg_desc[] = {
        PMBUS_REGULATOR_ONE_NODE("vout"),
};

struct tda38640_data {
        struct pmbus_driver_info info;
        u32 en_pin_lvl;
};

#define to_tda38640_data(x)  container_of(x, struct tda38640_data, info)

/*
 * Map PB_ON_OFF_CONFIG_POLARITY_HIGH to PB_OPERATION_CONTROL_ON.
 */
static int tda38640_read_byte_data(struct i2c_client *client, int page, int reg)
{
        const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
        struct tda38640_data *data = to_tda38640_data(info);
        int ret, on_off_config, enabled;

        if (reg != PMBUS_OPERATION)
                return -ENODATA;

        ret = pmbus_read_byte_data(client, page, reg);
        if (ret < 0)
                return ret;

        on_off_config = pmbus_read_byte_data(client, page,
                                             PMBUS_ON_OFF_CONFIG);
        if (on_off_config < 0)
                return on_off_config;

        enabled = !!(on_off_config & PB_ON_OFF_CONFIG_POLARITY_HIGH);

        enabled ^= data->en_pin_lvl;
        if (enabled)
                ret &= ~PB_OPERATION_CONTROL_ON;
        else
                ret |= PB_OPERATION_CONTROL_ON;

        return ret;
}

/*
 * Map PB_OPERATION_CONTROL_ON to PB_ON_OFF_CONFIG_POLARITY_HIGH.
 */
static int tda38640_write_byte_data(struct i2c_client *client, int page,
                                    int reg, u8 byte)
{
        const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
        struct tda38640_data *data = to_tda38640_data(info);
        int enable, ret;

        if (reg != PMBUS_OPERATION)
                return -ENODATA;

        enable = !!(byte & PB_OPERATION_CONTROL_ON);

        byte &= ~PB_OPERATION_CONTROL_ON;
        ret = pmbus_write_byte_data(client, page, reg, byte);
        if (ret < 0)
                return ret;

        enable ^= data->en_pin_lvl;

        return pmbus_update_byte_data(client, page, PMBUS_ON_OFF_CONFIG,
                                      PB_ON_OFF_CONFIG_POLARITY_HIGH,
                                      enable ? 0 : PB_ON_OFF_CONFIG_POLARITY_HIGH);
}

static int svid_mode(struct i2c_client *client, struct tda38640_data *data)
{
        /* PMBUS_MFR_READ(0xD0) + MTP Address offset */
        u8 write_buf[] = {0xd0, 0x44, 0x00};
        u8 read_buf[2];
        int ret, svid;
        bool off, reg_en_pin_pol;

        struct i2c_msg msgs[2] = {
                {
                        .addr = client->addr,
                        .flags = 0,
                        .buf = write_buf,
                        .len = sizeof(write_buf),
                },
                {
                        .addr = client->addr,
                        .flags = I2C_M_RD,
                        .buf = read_buf,
                        .len = sizeof(read_buf),
                }
        };

        ret = i2c_transfer(client->adapter, msgs, 2);
        if (ret < 0) {
                dev_err(&client->dev, "i2c_transfer failed. %d", ret);
                return ret;
        }

        /*
         * 0x44[15] determines PMBus Operating Mode
         * If bit is set then it is SVID mode.
         */
        svid = !!(read_buf[1] & BIT(7));

        /*
         * Determine EN pin level for use in SVID mode.
         * This is done with help of STATUS_BYTE bit 6(OFF) & ON_OFF_CONFIG bit 2(EN pin polarity).
         */
        if (svid) {
                ret = i2c_smbus_read_byte_data(client, PMBUS_STATUS_BYTE);
                if (ret < 0)
                        return ret;
                off = !!(ret & PB_STATUS_OFF);

                ret = i2c_smbus_read_byte_data(client, PMBUS_ON_OFF_CONFIG);
                if (ret < 0)
                        return ret;
                reg_en_pin_pol = !!(ret & PB_ON_OFF_CONFIG_POLARITY_HIGH);
                data->en_pin_lvl = off ^ reg_en_pin_pol;
        }

        return svid;
}

static struct pmbus_driver_info tda38640_info = {
        .pages = 1,
        .format[PSC_VOLTAGE_IN] = linear,
        .format[PSC_VOLTAGE_OUT] = linear,
        .format[PSC_CURRENT_OUT] = linear,
        .format[PSC_CURRENT_IN] = linear,
        .format[PSC_POWER] = linear,
        .format[PSC_TEMPERATURE] = linear,
        .func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_STATUS_INPUT
            | PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP
            | PMBUS_HAVE_IIN
            | PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT
            | PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT
            | PMBUS_HAVE_POUT | PMBUS_HAVE_PIN,
#if IS_ENABLED(CONFIG_SENSORS_TDA38640_REGULATOR)
        .num_regulators = 1,
        .reg_desc = tda38640_reg_desc,
#endif
};

static int tda38640_probe(struct i2c_client *client)
{
        struct tda38640_data *data;
        int svid;

        data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
        if (!data)
                return -ENOMEM;
        memcpy(&data->info, &tda38640_info, sizeof(tda38640_info));

        if (IS_ENABLED(CONFIG_SENSORS_TDA38640_REGULATOR) &&
            of_property_read_bool(client->dev.of_node, "infineon,en-pin-fixed-level")) {
                svid = svid_mode(client, data);
                if (svid < 0) {
                        dev_err_probe(&client->dev, svid, "Could not determine operating mode.");
                        return svid;
                }

                /*
                 * Apply ON_OFF_CONFIG workaround as enabling the regulator using the
                 * OPERATION register doesn't work in SVID mode.
                 *
                 * One should configure PMBUS_ON_OFF_CONFIG here, but
                 * PB_ON_OFF_CONFIG_POWERUP_CONTROL and PB_ON_OFF_CONFIG_EN_PIN_REQ
                 * are ignored by the device.
                 * Only PB_ON_OFF_CONFIG_POLARITY_HIGH has an effect.
                 */
                if (svid) {
                        data->info.read_byte_data = tda38640_read_byte_data;
                        data->info.write_byte_data = tda38640_write_byte_data;
                }
        }
        return pmbus_do_probe(client, &data->info);
}

static const struct i2c_device_id tda38640_id[] = {
        {"tda38640"},
        {}
};
MODULE_DEVICE_TABLE(i2c, tda38640_id);

static const struct of_device_id __maybe_unused tda38640_of_match[] = {
        { .compatible = "infineon,tda38640"},
        { },
};
MODULE_DEVICE_TABLE(of, tda38640_of_match);

/* This is the driver that will be inserted */
static struct i2c_driver tda38640_driver = {
        .driver = {
                .name = "tda38640",
                .of_match_table = of_match_ptr(tda38640_of_match),
        },
        .probe = tda38640_probe,
        .id_table = tda38640_id,
};

module_i2c_driver(tda38640_driver);

MODULE_AUTHOR("Patrick Rudolph <patrick.rudolph@9elements.com>");
MODULE_DESCRIPTION("PMBus driver for Infineon TDA38640");
MODULE_LICENSE("GPL");
MODULE_IMPORT_NS("PMBUS");