/*
   *  MEN 14F021P00 Board Management Controller (BMC) MFD Core Driver.
   *
   *  Copyright (C) 2014 MEN Mikro Elektronik Nuernberg GmbH
   *
   *  This program is free software; you can redistribute  it and/or modify it
   *  under  the terms of  the GNU General  Public License as published by the
   *  Free Software Foundation;  either version 2 of the  License, or (at your
   *  option) any later version.
   */
  
  #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
  ");
  
  		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, const struct i2c_device_id *ids)
  {
  	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
  ");
  		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
  ");
  		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
  ");
  		return rev_main;
  	}
  
  	dev_info(&client->dev, "FW Revision: %02d.%02d.%02d
  ",
  		 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
  ");
  		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
  ");
  		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");