drivers/watchdog/menf21bmc_wdt.c

   1 /*
   2  *  MEN 14F021P00 Board Management Controller (BMC) Watchdog 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/watchdog.h>
  16 #include <linux/platform_device.h>
  17 #include <linux/i2c.h>
  18
  19 #define DEVNAME "menf21bmc_wdt"
  20
  21 #define BMC_CMD_WD_ON           0x11
  22 #define BMC_CMD_WD_OFF          0x12
  23 #define BMC_CMD_WD_TRIG         0x13
  24 #define BMC_CMD_WD_TIME         0x14
  25 #define BMC_CMD_WD_STATE        0x17
  26 #define BMC_WD_OFF_VAL          0x69
  27 #define BMC_CMD_RST_RSN         0x92
  28
  29 #define BMC_WD_TIMEOUT_MIN      1       /* in sec */
  30 #define BMC_WD_TIMEOUT_MAX      6553    /* in sec */
  31
  32 static bool nowayout = WATCHDOG_NOWAYOUT;
  33 module_param(nowayout, bool, 0);
  34 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
  35                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  36
  37 struct menf21bmc_wdt {
  38         struct watchdog_device wdt;
  39         struct i2c_client *i2c_client;
  40 };
  41
  42 static int menf21bmc_wdt_set_bootstatus(struct menf21bmc_wdt *data)
  43 {
  44         int rst_rsn;
  45
  46         rst_rsn = i2c_smbus_read_byte_data(data->i2c_client, BMC_CMD_RST_RSN);
  47         if (rst_rsn < 0)
  48                 return rst_rsn;
  49
  50         if (rst_rsn == 0x02)
  51                 data->wdt.bootstatus |= WDIOF_CARDRESET;
  52         else if (rst_rsn == 0x05)
  53                 data->wdt.bootstatus |= WDIOF_EXTERN1;
  54         else if (rst_rsn == 0x06)
  55                 data->wdt.bootstatus |= WDIOF_EXTERN2;
  56         else if (rst_rsn == 0x0A)
  57                 data->wdt.bootstatus |= WDIOF_POWERUNDER;
  58
  59         return 0;
  60 }
  61
  62 static int menf21bmc_wdt_start(struct watchdog_device *wdt)
  63 {
  64         struct menf21bmc_wdt *drv_data = watchdog_get_drvdata(wdt);
  65
  66         return i2c_smbus_write_byte(drv_data->i2c_client, BMC_CMD_WD_ON);
  67 }
  68
  69 static int menf21bmc_wdt_stop(struct watchdog_device *wdt)
  70 {
  71         struct menf21bmc_wdt *drv_data = watchdog_get_drvdata(wdt);
  72
  73         return i2c_smbus_write_byte_data(drv_data->i2c_client,
  74                                          BMC_CMD_WD_OFF, BMC_WD_OFF_VAL);
  75 }
  76
  77 static int
  78 menf21bmc_wdt_settimeout(struct watchdog_device *wdt, unsigned int timeout)
  79 {
  80         int ret;
  81         struct menf21bmc_wdt *drv_data = watchdog_get_drvdata(wdt);
  82
  83         /*
  84          *  BMC Watchdog does have a resolution of 100ms.
  85          *  Watchdog API defines the timeout in seconds, so we have to
  86          *  multiply the value.
  87          */
  88         ret = i2c_smbus_write_word_data(drv_data->i2c_client,
  89                                         BMC_CMD_WD_TIME, timeout * 10);
  90         if (ret < 0)
  91                 return ret;
  92
  93         wdt->timeout = timeout;
  94
  95         return 0;
  96 }
  97
  98 static int menf21bmc_wdt_ping(struct watchdog_device *wdt)
  99 {
 100         struct menf21bmc_wdt *drv_data = watchdog_get_drvdata(wdt);
 101
 102         return i2c_smbus_write_byte(drv_data->i2c_client, BMC_CMD_WD_TRIG);
 103 }
 104
 105 static const struct watchdog_info menf21bmc_wdt_info = {
 106         .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
 107         .identity = DEVNAME,
 108 };
 109
 110 static const struct watchdog_ops menf21bmc_wdt_ops = {
 111         .owner          = THIS_MODULE,
 112         .start          = menf21bmc_wdt_start,
 113         .stop           = menf21bmc_wdt_stop,
 114         .ping           = menf21bmc_wdt_ping,
 115         .set_timeout    = menf21bmc_wdt_settimeout,
 116 };
 117
 118 static int menf21bmc_wdt_probe(struct platform_device *pdev)
 119 {
 120         int ret, bmc_timeout;
 121         struct menf21bmc_wdt *drv_data;
 122         struct i2c_client *i2c_client = to_i2c_client(pdev->dev.parent);
 123
 124         drv_data = devm_kzalloc(&pdev->dev,
 125                                 sizeof(struct menf21bmc_wdt), GFP_KERNEL);
 126         if (!drv_data)
 127                 return -ENOMEM;
 128
 129         drv_data->wdt.ops = &menf21bmc_wdt_ops;
 130         drv_data->wdt.info = &menf21bmc_wdt_info;
 131         drv_data->wdt.min_timeout = BMC_WD_TIMEOUT_MIN;
 132         drv_data->wdt.max_timeout = BMC_WD_TIMEOUT_MAX;
 133         drv_data->i2c_client = i2c_client;
 134
 135         /*
 136          * Get the current wdt timeout value from the BMC because
 137          * the BMC will save the value set before if the system restarts.
 138          */
 139         bmc_timeout = i2c_smbus_read_word_data(drv_data->i2c_client,
 140                                                BMC_CMD_WD_TIME);
 141         if (bmc_timeout < 0) {
 142                 dev_err(&pdev->dev, "failed to get current WDT timeout\n");
 143                 return bmc_timeout;
 144         }
 145
 146         watchdog_init_timeout(&drv_data->wdt, bmc_timeout / 10, &pdev->dev);
 147         watchdog_set_nowayout(&drv_data->wdt, nowayout);
 148         watchdog_set_drvdata(&drv_data->wdt, drv_data);
 149         platform_set_drvdata(pdev, drv_data);
 150
 151         ret = menf21bmc_wdt_set_bootstatus(drv_data);
 152         if (ret < 0) {
 153                 dev_err(&pdev->dev, "failed to set Watchdog bootstatus\n");
 154                 return ret;
 155         }
 156
 157         ret = watchdog_register_device(&drv_data->wdt);
 158         if (ret) {
 159                 dev_err(&pdev->dev, "failed to register Watchdog device\n");
 160                 return ret;
 161         }
 162
 163         dev_info(&pdev->dev, "MEN 14F021P00 BMC Watchdog device enabled\n");
 164
 165         return 0;
 166 }
 167
 168 static int menf21bmc_wdt_remove(struct platform_device *pdev)
 169 {
 170         struct menf21bmc_wdt *drv_data = platform_get_drvdata(pdev);
 171
 172         dev_warn(&pdev->dev,
 173                  "Unregister MEN 14F021P00 BMC Watchdog device, board may reset\n");
 174
 175         watchdog_unregister_device(&drv_data->wdt);
 176
 177         return 0;
 178 }
 179
 180 static void menf21bmc_wdt_shutdown(struct platform_device *pdev)
 181 {
 182         struct menf21bmc_wdt *drv_data = platform_get_drvdata(pdev);
 183
 184         i2c_smbus_write_word_data(drv_data->i2c_client,
 185                                   BMC_CMD_WD_OFF, BMC_WD_OFF_VAL);
 186 }
 187
 188 static struct  platform_driver menf21bmc_wdt = {
 189         .driver         = {
 190                 .name   = DEVNAME,
 191         },
 192         .probe          = menf21bmc_wdt_probe,
 193         .remove         = menf21bmc_wdt_remove,
 194         .shutdown       = menf21bmc_wdt_shutdown,
 195 };
 196
 197 module_platform_driver(menf21bmc_wdt);
 198
 199 MODULE_DESCRIPTION("MEN 14F021P00 BMC Watchdog driver");
 200 MODULE_AUTHOR("Andreas Werner <andreas.werner@men.de>");
 201 MODULE_LICENSE("GPL v2");
 202 MODULE_ALIAS("platform:menf21bmc_wdt");