drivers/watchdog/ts72xx_wdt.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Watchdog driver for Technologic Systems TS-72xx based SBCs
   4  * (TS-7200, TS-7250 and TS-7260). These boards have external
   5  * glue logic CPLD chip, which includes programmable watchdog
   6  * timer.
   7  *
   8  * Copyright (c) 2009 Mika Westerberg <mika.westerberg@iki.fi>
   9  *
  10  * This driver is based on ep93xx_wdt and wm831x_wdt drivers.
  11  *
  12  */
  13
  14 #include <linux/platform_device.h>
  15 #include <linux/module.h>
  16 #include <linux/watchdog.h>
  17 #include <linux/io.h>
  18
  19 #define TS72XX_WDT_DEFAULT_TIMEOUT      30
  20
  21 static int timeout;
  22 module_param(timeout, int, 0);
  23 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds.");
  24
  25 static bool nowayout = WATCHDOG_NOWAYOUT;
  26 module_param(nowayout, bool, 0);
  27 MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
  28
  29 /* priv->control_reg */
  30 #define TS72XX_WDT_CTRL_DISABLE         0x00
  31 #define TS72XX_WDT_CTRL_250MS           0x01
  32 #define TS72XX_WDT_CTRL_500MS           0x02
  33 #define TS72XX_WDT_CTRL_1SEC            0x03
  34 #define TS72XX_WDT_CTRL_RESERVED        0x04
  35 #define TS72XX_WDT_CTRL_2SEC            0x05
  36 #define TS72XX_WDT_CTRL_4SEC            0x06
  37 #define TS72XX_WDT_CTRL_8SEC            0x07
  38
  39 /* priv->feed_reg */
  40 #define TS72XX_WDT_FEED_VAL             0x05
  41
  42 struct ts72xx_wdt_priv {
  43         void __iomem    *control_reg;
  44         void __iomem    *feed_reg;
  45         struct watchdog_device wdd;
  46         unsigned char regval;
  47 };
  48
  49 static int ts72xx_wdt_start(struct watchdog_device *wdd)
  50 {
  51         struct ts72xx_wdt_priv *priv = watchdog_get_drvdata(wdd);
  52
  53         writeb(TS72XX_WDT_FEED_VAL, priv->feed_reg);
  54         writeb(priv->regval, priv->control_reg);
  55
  56         return 0;
  57 }
  58
  59 static int ts72xx_wdt_stop(struct watchdog_device *wdd)
  60 {
  61         struct ts72xx_wdt_priv *priv = watchdog_get_drvdata(wdd);
  62
  63         writeb(TS72XX_WDT_FEED_VAL, priv->feed_reg);
  64         writeb(TS72XX_WDT_CTRL_DISABLE, priv->control_reg);
  65
  66         return 0;
  67 }
  68
  69 static int ts72xx_wdt_ping(struct watchdog_device *wdd)
  70 {
  71         struct ts72xx_wdt_priv *priv = watchdog_get_drvdata(wdd);
  72
  73         writeb(TS72XX_WDT_FEED_VAL, priv->feed_reg);
  74
  75         return 0;
  76 }
  77
  78 static int ts72xx_wdt_settimeout(struct watchdog_device *wdd, unsigned int to)
  79 {
  80         struct ts72xx_wdt_priv *priv = watchdog_get_drvdata(wdd);
  81
  82         if (to == 1) {
  83                 priv->regval = TS72XX_WDT_CTRL_1SEC;
  84         } else if (to == 2) {
  85                 priv->regval = TS72XX_WDT_CTRL_2SEC;
  86         } else if (to <= 4) {
  87                 priv->regval = TS72XX_WDT_CTRL_4SEC;
  88                 to = 4;
  89         } else {
  90                 priv->regval = TS72XX_WDT_CTRL_8SEC;
  91                 if (to <= 8)
  92                         to = 8;
  93         }
  94
  95         wdd->timeout = to;
  96
  97         if (watchdog_active(wdd)) {
  98                 ts72xx_wdt_stop(wdd);
  99                 ts72xx_wdt_start(wdd);
 100         }
 101
 102         return 0;
 103 }
 104
 105 static const struct watchdog_info ts72xx_wdt_ident = {
 106         .options                = WDIOF_KEEPALIVEPING |
 107                                   WDIOF_SETTIMEOUT |
 108                                   WDIOF_MAGICCLOSE,
 109         .firmware_version       = 1,
 110         .identity               = "TS-72XX WDT",
 111 };
 112
 113 static const struct watchdog_ops ts72xx_wdt_ops = {
 114         .owner          = THIS_MODULE,
 115         .start          = ts72xx_wdt_start,
 116         .stop           = ts72xx_wdt_stop,
 117         .ping           = ts72xx_wdt_ping,
 118         .set_timeout    = ts72xx_wdt_settimeout,
 119 };
 120
 121 static int ts72xx_wdt_probe(struct platform_device *pdev)
 122 {
 123         struct device *dev = &pdev->dev;
 124         struct ts72xx_wdt_priv *priv;
 125         struct watchdog_device *wdd;
 126         int ret;
 127
 128         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 129         if (!priv)
 130                 return -ENOMEM;
 131
 132         priv->control_reg = devm_platform_ioremap_resource(pdev, 0);
 133         if (IS_ERR(priv->control_reg))
 134                 return PTR_ERR(priv->control_reg);
 135
 136         priv->feed_reg = devm_platform_ioremap_resource(pdev, 1);
 137         if (IS_ERR(priv->feed_reg))
 138                 return PTR_ERR(priv->feed_reg);
 139
 140         wdd = &priv->wdd;
 141         wdd->info = &ts72xx_wdt_ident;
 142         wdd->ops = &ts72xx_wdt_ops;
 143         wdd->min_timeout = 1;
 144         wdd->max_hw_heartbeat_ms = 8000;
 145         wdd->parent = dev;
 146
 147         watchdog_set_nowayout(wdd, nowayout);
 148
 149         wdd->timeout = TS72XX_WDT_DEFAULT_TIMEOUT;
 150         watchdog_init_timeout(wdd, timeout, dev);
 151
 152         watchdog_set_drvdata(wdd, priv);
 153
 154         ret = devm_watchdog_register_device(dev, wdd);
 155         if (ret)
 156                 return ret;
 157
 158         dev_info(dev, "TS-72xx Watchdog driver\n");
 159
 160         return 0;
 161 }
 162
 163 static struct platform_driver ts72xx_wdt_driver = {
 164         .probe          = ts72xx_wdt_probe,
 165         .driver         = {
 166                 .name   = "ts72xx-wdt",
 167         },
 168 };
 169
 170 module_platform_driver(ts72xx_wdt_driver);
 171
 172 MODULE_AUTHOR("Mika Westerberg <mika.westerberg@iki.fi>");
 173 MODULE_DESCRIPTION("TS-72xx SBC Watchdog");
 174 MODULE_LICENSE("GPL");
 175 MODULE_ALIAS("platform:ts72xx-wdt");