drivers/watchdog/ts72xx_wdt.c

   1 /*
   2  * Watchdog driver for Technologic Systems TS-72xx based SBCs
   3  * (TS-7200, TS-7250 and TS-7260). These boards have external
   4  * glue logic CPLD chip, which includes programmable watchdog
   5  * timer.
   6  *
   7  * Copyright (c) 2009 Mika Westerberg <mika.westerberg@iki.fi>
   8  *
   9  * This driver is based on ep93xx_wdt and wm831x_wdt drivers.
  10  *
  11  * This file is licensed under the terms of the GNU General Public
  12  * License version 2. This program is licensed "as is" without any
  13  * warranty of any kind, whether express or implied.
  14  */
  15
  16 #include <linux/platform_device.h>
  17 #include <linux/module.h>
  18 #include <linux/watchdog.h>
  19 #include <linux/io.h>
  20
  21 #define TS72XX_WDT_DEFAULT_TIMEOUT      30
  22
  23 static int timeout;
  24 module_param(timeout, int, 0);
  25 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds.");
  26
  27 static bool nowayout = WATCHDOG_NOWAYOUT;
  28 module_param(nowayout, bool, 0);
  29 MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
  30
  31 /* priv->control_reg */
  32 #define TS72XX_WDT_CTRL_DISABLE         0x00
  33 #define TS72XX_WDT_CTRL_250MS           0x01
  34 #define TS72XX_WDT_CTRL_500MS           0x02
  35 #define TS72XX_WDT_CTRL_1SEC            0x03
  36 #define TS72XX_WDT_CTRL_RESERVED        0x04
  37 #define TS72XX_WDT_CTRL_2SEC            0x05
  38 #define TS72XX_WDT_CTRL_4SEC            0x06
  39 #define TS72XX_WDT_CTRL_8SEC            0x07
  40
  41 /* priv->feed_reg */
  42 #define TS72XX_WDT_FEED_VAL             0x05
  43
  44 struct ts72xx_wdt_priv {
  45         void __iomem    *control_reg;
  46         void __iomem    *feed_reg;
  47         struct watchdog_device wdd;
  48         unsigned char regval;
  49 };
  50
  51 static int ts72xx_wdt_start(struct watchdog_device *wdd)
  52 {
  53         struct ts72xx_wdt_priv *priv = watchdog_get_drvdata(wdd);
  54
  55         writeb(TS72XX_WDT_FEED_VAL, priv->feed_reg);
  56         writeb(priv->regval, priv->control_reg);
  57
  58         return 0;
  59 }
  60
  61 static int ts72xx_wdt_stop(struct watchdog_device *wdd)
  62 {
  63         struct ts72xx_wdt_priv *priv = watchdog_get_drvdata(wdd);
  64
  65         writeb(TS72XX_WDT_FEED_VAL, priv->feed_reg);
  66         writeb(TS72XX_WDT_CTRL_DISABLE, priv->control_reg);
  67
  68         return 0;
  69 }
  70
  71 static int ts72xx_wdt_ping(struct watchdog_device *wdd)
  72 {
  73         struct ts72xx_wdt_priv *priv = watchdog_get_drvdata(wdd);
  74
  75         writeb(TS72XX_WDT_FEED_VAL, priv->feed_reg);
  76
  77         return 0;
  78 }
  79
  80 static int ts72xx_wdt_settimeout(struct watchdog_device *wdd, unsigned int to)
  81 {
  82         struct ts72xx_wdt_priv *priv = watchdog_get_drvdata(wdd);
  83
  84         if (to == 1) {
  85                 priv->regval = TS72XX_WDT_CTRL_1SEC;
  86         } else if (to == 2) {
  87                 priv->regval = TS72XX_WDT_CTRL_2SEC;
  88         } else if (to <= 4) {
  89                 priv->regval = TS72XX_WDT_CTRL_4SEC;
  90                 to = 4;
  91         } else {
  92                 priv->regval = TS72XX_WDT_CTRL_8SEC;
  93                 if (to <= 8)
  94                         to = 8;
  95         }
  96
  97         wdd->timeout = to;
  98
  99         if (watchdog_active(wdd)) {
 100                 ts72xx_wdt_stop(wdd);
 101                 ts72xx_wdt_start(wdd);
 102         }
 103
 104         return 0;
 105 }
 106
 107 static const struct watchdog_info ts72xx_wdt_ident = {
 108         .options                = WDIOF_KEEPALIVEPING |
 109                                   WDIOF_SETTIMEOUT |
 110                                   WDIOF_MAGICCLOSE,
 111         .firmware_version       = 1,
 112         .identity               = "TS-72XX WDT",
 113 };
 114
 115 static const struct watchdog_ops ts72xx_wdt_ops = {
 116         .owner          = THIS_MODULE,
 117         .start          = ts72xx_wdt_start,
 118         .stop           = ts72xx_wdt_stop,
 119         .ping           = ts72xx_wdt_ping,
 120         .set_timeout    = ts72xx_wdt_settimeout,
 121 };
 122
 123 static int ts72xx_wdt_probe(struct platform_device *pdev)
 124 {
 125         struct device *dev = &pdev->dev;
 126         struct ts72xx_wdt_priv *priv;
 127         struct watchdog_device *wdd;
 128         int ret;
 129
 130         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 131         if (!priv)
 132                 return -ENOMEM;
 133
 134         priv->control_reg = devm_platform_ioremap_resource(pdev, 0);
 135         if (IS_ERR(priv->control_reg))
 136                 return PTR_ERR(priv->control_reg);
 137
 138         priv->feed_reg = devm_platform_ioremap_resource(pdev, 1);
 139         if (IS_ERR(priv->feed_reg))
 140                 return PTR_ERR(priv->feed_reg);
 141
 142         wdd = &priv->wdd;
 143         wdd->info = &ts72xx_wdt_ident;
 144         wdd->ops = &ts72xx_wdt_ops;
 145         wdd->min_timeout = 1;
 146         wdd->max_hw_heartbeat_ms = 8000;
 147         wdd->parent = dev;
 148
 149         watchdog_set_nowayout(wdd, nowayout);
 150
 151         wdd->timeout = TS72XX_WDT_DEFAULT_TIMEOUT;
 152         watchdog_init_timeout(wdd, timeout, dev);
 153
 154         watchdog_set_drvdata(wdd, priv);
 155
 156         ret = devm_watchdog_register_device(dev, wdd);
 157         if (ret)
 158                 return ret;
 159
 160         dev_info(dev, "TS-72xx Watchdog driver\n");
 161
 162         return 0;
 163 }
 164
 165 static struct platform_driver ts72xx_wdt_driver = {
 166         .probe          = ts72xx_wdt_probe,
 167         .driver         = {
 168                 .name   = "ts72xx-wdt",
 169         },
 170 };
 171
 172 module_platform_driver(ts72xx_wdt_driver);
 173
 174 MODULE_AUTHOR("Mika Westerberg <mika.westerberg@iki.fi>");
 175 MODULE_DESCRIPTION("TS-72xx SBC Watchdog");
 176 MODULE_LICENSE("GPL");
 177 MODULE_ALIAS("platform:ts72xx-wdt");