1/*
  2 *  MEN 14F021P00 Board Management Controller (BMC) MFD Core Driver.
  3 *
  4 *  Copyright (C) 2014 MEN Mikro Elektronik Nuernberg GmbH
  5 *
  6 *  This program is free software; you can redistribute  it and/or modify it
  7 *  under  the terms of  the GNU General  Public License as published by the
  8 *  Free Software Foundation;  either version 2 of the  License, or (at your
  9 *  option) any later version.
 10 */
 11
 12#include <linux/kernel.h>
 13#include <linux/device.h>
 14#include <linux/module.h>
 15#include <linux/i2c.h>
 16#include <linux/mfd/core.h>
 17
 18#define BMC_CMD_WDT_EXIT_PROD	0x18
 19#define BMC_CMD_WDT_PROD_STAT	0x19
 20#define BMC_CMD_REV_MAJOR	0x80
 21#define BMC_CMD_REV_MINOR	0x81
 22#define BMC_CMD_REV_MAIN	0x82
 23
 24static struct mfd_cell menf21bmc_cell[] = {
 25	{ .name = "menf21bmc_wdt", },
 26	{ .name = "menf21bmc_led", },
 27	{ .name = "menf21bmc_hwmon", }
 28};
 29
 30static int menf21bmc_wdt_exit_prod_mode(struct i2c_client *client)
 31{
 32	int val, ret;
 33
 34	val = i2c_smbus_read_byte_data(client, BMC_CMD_WDT_PROD_STAT);
 35	if (val < 0)
 36		return val;
 37
 38	/*
 39	 * Production mode should be not active after delivery of the Board.
 40	 * To be sure we check it, inform the user and exit the mode
 41	 * if active.
 42	 */
 43	if (val == 0x00) {
 44		dev_info(&client->dev,
 45			"BMC in production mode. Exit production mode\n");
 46
 47		ret = i2c_smbus_write_byte(client, BMC_CMD_WDT_EXIT_PROD);
 48		if (ret < 0)
 49			return ret;
 50	}
 51
 52	return 0;
 53}
 54
 55static int
 56menf21bmc_probe(struct i2c_client *client, const struct i2c_device_id *ids)
 57{
 58	int rev_major, rev_minor, rev_main;
 59	int ret;
 60
 61	ret = i2c_check_functionality(client->adapter,
 62				      I2C_FUNC_SMBUS_BYTE_DATA |
 63				      I2C_FUNC_SMBUS_WORD_DATA |
 64				      I2C_FUNC_SMBUS_BYTE);
 65	if (!ret)
 66		return -ENODEV;
 67
 68	rev_major = i2c_smbus_read_word_data(client, BMC_CMD_REV_MAJOR);
 69	if (rev_major < 0) {
 70		dev_err(&client->dev, "failed to get BMC major revision\n");
 71		return rev_major;
 72	}
 73
 74	rev_minor = i2c_smbus_read_word_data(client, BMC_CMD_REV_MINOR);
 75	if (rev_minor < 0) {
 76		dev_err(&client->dev, "failed to get BMC minor revision\n");
 77		return rev_minor;
 78	}
 79
 80	rev_main = i2c_smbus_read_word_data(client, BMC_CMD_REV_MAIN);
 81	if (rev_main < 0) {
 82		dev_err(&client->dev, "failed to get BMC main revision\n");
 83		return rev_main;
 84	}
 85
 86	dev_info(&client->dev, "FW Revision: %02d.%02d.%02d\n",
 87		 rev_major, rev_minor, rev_main);
 88
 89	/*
 90	 * We have to exit the Production Mode of the BMC to activate the
 91	 * Watchdog functionality and the BIOS life sign monitoring.
 92	 */
 93	ret = menf21bmc_wdt_exit_prod_mode(client);
 94	if (ret < 0) {
 95		dev_err(&client->dev, "failed to leave production mode\n");
 96		return ret;
 97	}
 98
 99	ret = devm_mfd_add_devices(&client->dev, 0, menf21bmc_cell,
100				   ARRAY_SIZE(menf21bmc_cell), NULL, 0, NULL);
101	if (ret < 0) {
102		dev_err(&client->dev, "failed to add BMC sub-devices\n");
103		return ret;
104	}
105
106	return 0;
107}
108
109static const struct i2c_device_id menf21bmc_id_table[] = {
110	{ "menf21bmc" },
111	{ }
112};
113MODULE_DEVICE_TABLE(i2c, menf21bmc_id_table);
114
115static struct i2c_driver menf21bmc_driver = {
116	.driver.name	= "menf21bmc",
117	.id_table	= menf21bmc_id_table,
118	.probe		= menf21bmc_probe,
119};
120
121module_i2c_driver(menf21bmc_driver);
122
123MODULE_DESCRIPTION("MEN 14F021P00 BMC mfd core driver");
124MODULE_AUTHOR("Andreas Werner <andreas.werner@men.de>");
125MODULE_LICENSE("GPL v2");