// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  MEN 14F021P00 Board Management Controller (BMC) MFD Core Driver.
 *
 *  Copyright (C) 2014 MEN Mikro Elektronik Nuernberg GmbH
 */

#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/mfd/core.h>

#define BMC_CMD_WDT_EXIT_PROD   0x18
#define BMC_CMD_WDT_PROD_STAT   0x19
#define BMC_CMD_REV_MAJOR       0x80
#define BMC_CMD_REV_MINOR       0x81
#define BMC_CMD_REV_MAIN        0x82

static struct mfd_cell menf21bmc_cell[] = {
        { .name = "menf21bmc_wdt", },
        { .name = "menf21bmc_led", },
        { .name = "menf21bmc_hwmon", }
};

static int menf21bmc_wdt_exit_prod_mode(struct i2c_client *client)
{
        int val, ret;

        val = i2c_smbus_read_byte_data(client, BMC_CMD_WDT_PROD_STAT);
        if (val < 0)
                return val;

        /*
         * Production mode should be not active after delivery of the Board.
         * To be sure we check it, inform the user and exit the mode
         * if active.
         */
        if (val == 0x00) {
                dev_info(&client->dev,
                        "BMC in production mode. Exit production mode\n");

                ret = i2c_smbus_write_byte(client, BMC_CMD_WDT_EXIT_PROD);
                if (ret < 0)
                        return ret;
        }

        return 0;
}

static int
menf21bmc_probe(struct i2c_client *client)
{
        int rev_major, rev_minor, rev_main;
        int ret;

        ret = i2c_check_functionality(client->adapter,
                                      I2C_FUNC_SMBUS_BYTE_DATA |
                                      I2C_FUNC_SMBUS_WORD_DATA |
                                      I2C_FUNC_SMBUS_BYTE);
        if (!ret)
                return -ENODEV;

        rev_major = i2c_smbus_read_word_data(client, BMC_CMD_REV_MAJOR);
        if (rev_major < 0) {
                dev_err(&client->dev, "failed to get BMC major revision\n");
                return rev_major;
        }

        rev_minor = i2c_smbus_read_word_data(client, BMC_CMD_REV_MINOR);
        if (rev_minor < 0) {
                dev_err(&client->dev, "failed to get BMC minor revision\n");
                return rev_minor;
        }

        rev_main = i2c_smbus_read_word_data(client, BMC_CMD_REV_MAIN);
        if (rev_main < 0) {
                dev_err(&client->dev, "failed to get BMC main revision\n");
                return rev_main;
        }

        dev_info(&client->dev, "FW Revision: %02d.%02d.%02d\n",
                 rev_major, rev_minor, rev_main);

        /*
         * We have to exit the Production Mode of the BMC to activate the
         * Watchdog functionality and the BIOS life sign monitoring.
         */
        ret = menf21bmc_wdt_exit_prod_mode(client);
        if (ret < 0) {
                dev_err(&client->dev, "failed to leave production mode\n");
                return ret;
        }

        ret = devm_mfd_add_devices(&client->dev, 0, menf21bmc_cell,
                                   ARRAY_SIZE(menf21bmc_cell), NULL, 0, NULL);
        if (ret < 0) {
                dev_err(&client->dev, "failed to add BMC sub-devices\n");
                return ret;
        }

        return 0;
}

static const struct i2c_device_id menf21bmc_id_table[] = {
        { "menf21bmc" },
        { }
};
MODULE_DEVICE_TABLE(i2c, menf21bmc_id_table);

static struct i2c_driver menf21bmc_driver = {
        .driver.name    = "menf21bmc",
        .id_table       = menf21bmc_id_table,
        .probe          = menf21bmc_probe,
};

module_i2c_driver(menf21bmc_driver);

MODULE_DESCRIPTION("MEN 14F021P00 BMC mfd core driver");
MODULE_AUTHOR("Andreas Werner <andreas.werner@men.de>");
MODULE_LICENSE("GPL v2");