LXR linux/drivers/watchdog/tqmx86

   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
  22static unsigned int timeout;
  23module_param(timeout, uint, 0);
  24MODULE_PARM_DESC(timeout,
  25        "Watchdog timeout in seconds. (1<=timeout<=4096, default="
  26                                __MODULE_STRING(WDT_TIMEOUT) ")");
  27struct 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
  35static 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
  44static 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
  59static const struct watchdog_info tqmx86_wdt_info = {
  60        .options        = WDIOF_SETTIMEOUT |
  61                          WDIOF_KEEPALIVEPING,
  62        .identity       = "TQMx86 Watchdog",
  63};
  64
  65static struct watchdog_ops tqmx86_wdt_ops = {
  66        .owner          = THIS_MODULE,
  67        .start          = tqmx86_wdt_start,
  68        .set_timeout    = tqmx86_wdt_set_timeout,
  69};
  70
  71static 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
 114static struct platform_driver tqmx86_wdt_driver = {
 115        .driver         = {
 116                .name   = "tqmx86-wdt",
 117        },
 118        .probe          = tqmx86_wdt_probe,
 119};
 120
 121module_platform_driver(tqmx86_wdt_driver);
 122
 123MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch>");
 124MODULE_DESCRIPTION("TQMx86 Watchdog");
 125MODULE_ALIAS("platform:tqmx86-wdt");
 126MODULE_LICENSE("GPL");
 127