drivers/mfd/menf21bmc.c

   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
  24 static struct mfd_cell menf21bmc_cell[] = {
  25         { .name = "menf21bmc_wdt", },
  26         { .name = "menf21bmc_led", },
  27         { .name = "menf21bmc_hwmon", }
  28 };
  29
  30 static 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
  55 static int
  56 menf21bmc_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
 109 static const struct i2c_device_id menf21bmc_id_table[] = {
 110         { "menf21bmc" },
 111         { }
 112 };
 113 MODULE_DEVICE_TABLE(i2c, menf21bmc_id_table);
 114
 115 static struct i2c_driver menf21bmc_driver = {
 116         .driver.name    = "menf21bmc",
 117         .id_table       = menf21bmc_id_table,
 118         .probe          = menf21bmc_probe,
 119 };
 120
 121 module_i2c_driver(menf21bmc_driver);
 122
 123 MODULE_DESCRIPTION("MEN 14F021P00 BMC mfd core driver");
 124 MODULE_AUTHOR("Andreas Werner <andreas.werner@men.de>");
 125 MODULE_LICENSE("GPL v2");