drivers/watchdog/tqmx86_wdt.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Watchdog driver for TQMx86 PLD.
   4  *
   5  * The watchdog supports power of 2 timeouts from 1 to 4096sec.
   6  * Once started, it cannot be stopped.
   7  *
   8  * Based on the vendor code written by Vadim V.Vlasov
   9  * <vvlasov@dev.rtsoft.ru>
  10  */
  11
  12 #include <linux/io.h>
  13 #include <linux/log2.h>
  14 #include <linux/module.h>
  15 #include <linux/platform_device.h>
  16 #include <linux/timer.h>
  17 #include <linux/watchdog.h>
  18
  19 /* default timeout (secs) */
  20 #define WDT_TIMEOUT 32
  21
  22 static unsigned int timeout;
  23 module_param(timeout, uint, 0);
  24 MODULE_PARM_DESC(timeout,
  25         "Watchdog timeout in seconds. (1<=timeout<=4096, default="
  26                                 __MODULE_STRING(WDT_TIMEOUT) ")");
  27 struct tqmx86_wdt {
  28         struct watchdog_device wdd;
  29         void __iomem *io_base;
  30 };
  31
  32 #define TQMX86_WDCFG    0x00 /* Watchdog Configuration Register */
  33 #define TQMX86_WDCS     0x01 /* Watchdog Config/Status Register */
  34
  35 static int tqmx86_wdt_start(struct watchdog_device *wdd)
  36 {
  37         struct tqmx86_wdt *priv = watchdog_get_drvdata(wdd);
  38
  39         iowrite8(0x81, priv->io_base + TQMX86_WDCS);
  40
  41         return 0;
  42 }
  43
  44 static int tqmx86_wdt_set_timeout(struct watchdog_device *wdd, unsigned int t)
  45 {
  46         struct tqmx86_wdt *priv = watchdog_get_drvdata(wdd);
  47         u8 val;
  48
  49         t = roundup_pow_of_two(t);
  50         val = ilog2(t) | 0x90;
  51         val += 3; /* values 0,1,2 correspond to 0.125,0.25,0.5s timeouts */
  52         iowrite8(val, priv->io_base + TQMX86_WDCFG);
  53
  54         wdd->timeout = t;
  55
  56         return 0;
  57 }
  58
  59 static const struct watchdog_info tqmx86_wdt_info = {
  60         .options        = WDIOF_SETTIMEOUT |
  61                           WDIOF_KEEPALIVEPING,
  62         .identity       = "TQMx86 Watchdog",
  63 };
  64
  65 static struct watchdog_ops tqmx86_wdt_ops = {
  66         .owner          = THIS_MODULE,
  67         .start          = tqmx86_wdt_start,
  68         .set_timeout    = tqmx86_wdt_set_timeout,
  69 };
  70
  71 static int tqmx86_wdt_probe(struct platform_device *pdev)
  72 {
  73         struct device *dev = &pdev->dev;
  74         struct tqmx86_wdt *priv;
  75         struct resource *res;
  76         int err;
  77
  78         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
  79         if (!priv)
  80                 return -ENOMEM;
  81
  82         res = platform_get_resource(pdev, IORESOURCE_IO, 0);
  83         if (!res)
  84                 return -ENODEV;
  85
  86         priv->io_base = devm_ioport_map(dev, res->start, resource_size(res));
  87         if (!priv->io_base)
  88                 return -ENOMEM;
  89
  90         watchdog_set_drvdata(&priv->wdd, priv);
  91
  92         priv->wdd.parent = dev;
  93         priv->wdd.info = &tqmx86_wdt_info;
  94         priv->wdd.ops = &tqmx86_wdt_ops;
  95         priv->wdd.min_timeout = 1;
  96         priv->wdd.max_timeout = 4096;
  97         priv->wdd.max_hw_heartbeat_ms = 4096*1000;
  98         priv->wdd.timeout = WDT_TIMEOUT;
  99
 100         watchdog_init_timeout(&priv->wdd, timeout, dev);
 101         watchdog_set_nowayout(&priv->wdd, WATCHDOG_NOWAYOUT);
 102
 103         tqmx86_wdt_set_timeout(&priv->wdd, priv->wdd.timeout);
 104
 105         err = devm_watchdog_register_device(dev, &priv->wdd);
 106         if (err)
 107                 return err;
 108
 109         dev_info(dev, "TQMx86 watchdog\n");
 110
 111         return 0;
 112 }
 113
 114 static struct platform_driver tqmx86_wdt_driver = {
 115         .driver         = {
 116                 .name   = "tqmx86-wdt",
 117         },
 118         .probe          = tqmx86_wdt_probe,
 119 };
 120
 121 module_platform_driver(tqmx86_wdt_driver);
 122
 123 MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch>");
 124 MODULE_DESCRIPTION("TQMx86 Watchdog");
 125 MODULE_ALIAS("platform:tqmx86-wdt");
 126 MODULE_LICENSE("GPL");