Quelle  ts72xx_wdt.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Watchdog driver for Technologic Systems TS-72xx based SBCs
 * (TS-7200, TS-7250 and TS-7260). These boards have external
 * glue logic CPLD chip, which includes programmable watchdog
 * timer.
 *
 * Copyright (c) 2009 Mika Westerberg <mika.westerberg@iki.fi>
 *
 * This driver is based on ep93xx_wdt and wm831x_wdt drivers.
 *
 */

#include <linux/platform_device.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/watchdog.h>
#include <linux/io.h>

#define TS72XX_WDT_DEFAULT_TIMEOUT 30

static int timeout;
module_param(timeout, int, 0);
MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds.");

static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");

/* priv->control_reg */
#define TS72XX_WDT_CTRL_DISABLE  0x00
#define TS72XX_WDT_CTRL_250MS  0x01
#define TS72XX_WDT_CTRL_500MS  0x02
#define TS72XX_WDT_CTRL_1SEC  0x03
#define TS72XX_WDT_CTRL_RESERVED 0x04
#define TS72XX_WDT_CTRL_2SEC  0x05
#define TS72XX_WDT_CTRL_4SEC  0x06
#define TS72XX_WDT_CTRL_8SEC  0x07

/* priv->feed_reg */
#define TS72XX_WDT_FEED_VAL  0x05

struct ts72xx_wdt_priv {
 void __iomem *control_reg;
 void __iomem *feed_reg;
 struct watchdog_device wdd;
 unsigned char regval;
};

static int ts72xx_wdt_start(struct watchdog_device *wdd)
{
 struct ts72xx_wdt_priv *priv = watchdog_get_drvdata(wdd);

 writeb(TS72XX_WDT_FEED_VAL, priv->feed_reg);
 writeb(priv->regval, priv->control_reg);

 return 0;
}

static int ts72xx_wdt_stop(struct watchdog_device *wdd)
{
 struct ts72xx_wdt_priv *priv = watchdog_get_drvdata(wdd);

 writeb(TS72XX_WDT_FEED_VAL, priv->feed_reg);
 writeb(TS72XX_WDT_CTRL_DISABLE, priv->control_reg);

 return 0;
}

static int ts72xx_wdt_ping(struct watchdog_device *wdd)
{
 struct ts72xx_wdt_priv *priv = watchdog_get_drvdata(wdd);

 writeb(TS72XX_WDT_FEED_VAL, priv->feed_reg);

 return 0;
}

static int ts72xx_wdt_settimeout(struct watchdog_device *wdd, unsigned int to)
{
 struct ts72xx_wdt_priv *priv = watchdog_get_drvdata(wdd);

 if (to == 1) {
  priv->regval = TS72XX_WDT_CTRL_1SEC;
 } else if (to == 2) {
  priv->regval = TS72XX_WDT_CTRL_2SEC;
 } else if (to <= 4) {
  priv->regval = TS72XX_WDT_CTRL_4SEC;
  to = 4;
 } else {
  priv->regval = TS72XX_WDT_CTRL_8SEC;
  if (to <= 8)
   to = 8;
 }

 wdd->timeout = to;

 if (watchdog_active(wdd)) {
  ts72xx_wdt_stop(wdd);
  ts72xx_wdt_start(wdd);
 }

 return 0;
}

static const struct watchdog_info ts72xx_wdt_ident = {
 .options  = WDIOF_KEEPALIVEPING |
      WDIOF_SETTIMEOUT |
      WDIOF_MAGICCLOSE,
 .firmware_version = 1,
 .identity  = "TS-72XX WDT",
};

static const struct watchdog_ops ts72xx_wdt_ops = {
 .owner  = THIS_MODULE,
 .start  = ts72xx_wdt_start,
 .stop  = ts72xx_wdt_stop,
 .ping  = ts72xx_wdt_ping,
 .set_timeout = ts72xx_wdt_settimeout,
};

static int ts72xx_wdt_probe(struct platform_device *pdev)
{
 struct device *dev = &pdev->dev;
 struct ts72xx_wdt_priv *priv;
 struct watchdog_device *wdd;
 int ret;

 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 if (!priv)
  return -ENOMEM;

 priv->control_reg = devm_platform_ioremap_resource(pdev, 0);
 if (IS_ERR(priv->control_reg))
  return PTR_ERR(priv->control_reg);

 priv->feed_reg = devm_platform_ioremap_resource(pdev, 1);
 if (IS_ERR(priv->feed_reg))
  return PTR_ERR(priv->feed_reg);

 wdd = &priv->wdd;
 wdd->info = &ts72xx_wdt_ident;
 wdd->ops = &ts72xx_wdt_ops;
 wdd->min_timeout = 1;
 wdd->max_hw_heartbeat_ms = 8000;
 wdd->parent = dev;

 watchdog_set_nowayout(wdd, nowayout);

 wdd->timeout = TS72XX_WDT_DEFAULT_TIMEOUT;
 watchdog_init_timeout(wdd, timeout, dev);

 watchdog_set_drvdata(wdd, priv);

 ret = devm_watchdog_register_device(dev, wdd);
 if (ret)
  return ret;

 dev_info(dev, "TS-72xx Watchdog driver\n");

 return 0;
}

static const struct of_device_id ts72xx_wdt_of_ids[] = {
 { .compatible = "technologic,ts7200-wdt" },
 { /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, ts72xx_wdt_of_ids);

static struct platform_driver ts72xx_wdt_driver = {
 .probe  = ts72xx_wdt_probe,
 .driver  = {
  .name = "ts72xx-wdt",
  .of_match_table = ts72xx_wdt_of_ids,
 },
};

module_platform_driver(ts72xx_wdt_driver);

MODULE_AUTHOR("Mika Westerberg ");
MODULE_DESCRIPTION("TS-72xx SBC Watchdog");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:ts72xx-wdt");