Merge git://www.linux-watchdog.org/linux-watchdog

Pull watchdog update from Wim Van Sebroeck:

 - New driver for Broadcom 7038 Set-Top Box
 - imx2_wdt: Use register definition in regmap_write()
 - intel-mid: add Magic Closure flag
 - watchdog framework improvements:
      - Use device tree alias for naming watchdogs
      - propagate ping error code to the user space
      - Always evaluate new timeout against min_timeout
      - Use single variable name for struct watchdog_device
 - include clean-ups

* git://www.linux-watchdog.org/linux-watchdog:
  watchdog: include: add units for timeout values in kerneldoc
  watchdog: include: fix some typos
  watchdog: core: propagate ping error code to the user space
  watchdog: watchdog_dev: Use single variable name for struct watchdog_device
  watchdog: Always evaluate new timeout against min_timeout
  watchdog: intel-mid: add Magic Closure flag
  watchdog: imx2_wdt: Use register definition in regmap_write()
  watchdog: watchdog_dev: Use device tree alias for naming watchdogs
  watchdog: Watchdog driver for Broadcom Set-Top Box
  watchdog: bcm7038: add device tree binding documentation

Documentation/devicetree/bindings/watchdog/brcm,bcm7038-wdt.txt

@@ -0,0 +1,19 @@
+BCM7038 Watchdog timer
+
+Required properties:
+
+- compatible : should be "brcm,bcm7038-wdt"
+- reg : Specifies base physical address and size of the registers.
+
+Optional properties:
+
+- clocks: The clock running the watchdog. If no clock is found the
+	  driver will default to 27000000 Hz.
+
+Example:
+
+watchdog@f040a7e8 {
+	compatible = "brcm,bcm7038-wdt";
+	clocks = <&upg_fixed>;
+	reg = <0xf040a7e8 0x16>;
+};

drivers/watchdog/Kconfig

@@ -1313,6 +1313,14 @@ config BCM_KONA_WDT_DEBUG
 
 	  If in doubt, say 'N'.
 
+config BCM7038_WDT
+	tristate "BCM7038 Watchdog"
+	select WATCHDOG_CORE
+	help
+	 Watchdog driver for the built-in hardware in Broadcom 7038 SoCs.
+
+	 Say 'Y or 'M' here to enable the driver.
+
 config IMGPDC_WDT
 	tristate "Imagination Technologies PDC Watchdog Timer"
 	depends on HAS_IOMEM

drivers/watchdog/Makefile

@@ -68,6 +68,7 @@ obj-$(CONFIG_MESON_WATCHDOG) += meson_wdt.o
 obj-$(CONFIG_MEDIATEK_WATCHDOG) += mtk_wdt.o
 obj-$(CONFIG_DIGICOLOR_WATCHDOG) += digicolor_wdt.o
 obj-$(CONFIG_LPC18XX_WATCHDOG) += lpc18xx_wdt.o
+obj-$(CONFIG_BCM7038_WDT) += bcm7038_wdt.o
 
 # AVR32 Architecture
 obj-$(CONFIG_AT32AP700X_WDT) += at32ap700x_wdt.o

drivers/watchdog/bcm7038_wdt.c

@@ -0,0 +1,237 @@
+/*
+ * Copyright (C) 2015 Broadcom Corporation
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/clk.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pm.h>
+#include <linux/watchdog.h>
+
+#define WDT_START_1		0xff00
+#define WDT_START_2		0x00ff
+#define WDT_STOP_1		0xee00
+#define WDT_STOP_2		0x00ee
+
+#define WDT_TIMEOUT_REG		0x0
+#define WDT_CMD_REG		0x4
+
+#define WDT_MIN_TIMEOUT		1 /* seconds */
+#define WDT_DEFAULT_TIMEOUT	30 /* seconds */
+#define WDT_DEFAULT_RATE	27000000
+
+struct bcm7038_watchdog {
+	void __iomem		*base;
+	struct watchdog_device	wdd;
+	u32			rate;
+	struct clk		*clk;
+};
+
+static bool nowayout = WATCHDOG_NOWAYOUT;
+
+static void bcm7038_wdt_set_timeout_reg(struct watchdog_device *wdog)
+{
+	struct bcm7038_watchdog *wdt = watchdog_get_drvdata(wdog);
+	u32 timeout;
+
+	timeout = wdt->rate * wdog->timeout;
+
+	writel(timeout, wdt->base + WDT_TIMEOUT_REG);
+}
+
+static int bcm7038_wdt_ping(struct watchdog_device *wdog)
+{
+	struct bcm7038_watchdog *wdt = watchdog_get_drvdata(wdog);
+
+	writel(WDT_START_1, wdt->base + WDT_CMD_REG);
+	writel(WDT_START_2, wdt->base + WDT_CMD_REG);
+
+	return 0;
+}
+
+static int bcm7038_wdt_start(struct watchdog_device *wdog)
+{
+	bcm7038_wdt_set_timeout_reg(wdog);
+	bcm7038_wdt_ping(wdog);
+
+	return 0;
+}
+
+static int bcm7038_wdt_stop(struct watchdog_device *wdog)
+{
+	struct bcm7038_watchdog *wdt = watchdog_get_drvdata(wdog);
+
+	writel(WDT_STOP_1, wdt->base + WDT_CMD_REG);
+	writel(WDT_STOP_2, wdt->base + WDT_CMD_REG);
+
+	return 0;
+}
+
+static int bcm7038_wdt_set_timeout(struct watchdog_device *wdog,
+				   unsigned int t)
+{
+	/* Can't modify timeout value if watchdog timer is running */
+	bcm7038_wdt_stop(wdog);
+	wdog->timeout = t;
+	bcm7038_wdt_start(wdog);
+
+	return 0;
+}
+
+static unsigned int bcm7038_wdt_get_timeleft(struct watchdog_device *wdog)
+{
+	struct bcm7038_watchdog *wdt = watchdog_get_drvdata(wdog);
+	u32 time_left;
+
+	time_left = readl(wdt->base + WDT_CMD_REG);
+
+	return time_left / wdt->rate;
+}
+
+static struct watchdog_info bcm7038_wdt_info = {
+	.identity	= "Broadcom BCM7038 Watchdog Timer",
+	.options	= WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
+				WDIOF_MAGICCLOSE
+};
+
+static struct watchdog_ops bcm7038_wdt_ops = {
+	.owner		= THIS_MODULE,
+	.start		= bcm7038_wdt_start,
+	.stop		= bcm7038_wdt_stop,
+	.set_timeout	= bcm7038_wdt_set_timeout,
+	.get_timeleft	= bcm7038_wdt_get_timeleft,
+};
+
+static int bcm7038_wdt_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct bcm7038_watchdog *wdt;
+	struct resource *res;
+	int err;
+
+	wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
+	if (!wdt)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, wdt);
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	wdt->base = devm_ioremap_resource(dev, res);
+	if (IS_ERR(wdt->base))
+		return PTR_ERR(wdt->base);
+
+	wdt->clk = devm_clk_get(dev, NULL);
+	/* If unable to get clock, use default frequency */
+	if (!IS_ERR(wdt->clk)) {
+		clk_prepare_enable(wdt->clk);
+		wdt->rate = clk_get_rate(wdt->clk);
+		/* Prevent divide-by-zero exception */
+		if (!wdt->rate)
+			wdt->rate = WDT_DEFAULT_RATE;
+	} else {
+		wdt->rate = WDT_DEFAULT_RATE;
+		wdt->clk = NULL;
+	}
+
+	wdt->wdd.info		= &bcm7038_wdt_info;
+	wdt->wdd.ops		= &bcm7038_wdt_ops;
+	wdt->wdd.min_timeout	= WDT_MIN_TIMEOUT;
+	wdt->wdd.timeout	= WDT_DEFAULT_TIMEOUT;
+	wdt->wdd.max_timeout	= 0xffffffff / wdt->rate;
+	wdt->wdd.parent		= dev;
+	watchdog_set_drvdata(&wdt->wdd, wdt);
+
+	err = watchdog_register_device(&wdt->wdd);
+	if (err) {
+		dev_err(dev, "Failed to register watchdog device\n");
+		clk_disable_unprepare(wdt->clk);
+		return err;
+	}
+
+	dev_info(dev, "Registered BCM7038 Watchdog\n");
+
+	return 0;
+}
+
+static int bcm7038_wdt_remove(struct platform_device *pdev)
+{
+	struct bcm7038_watchdog *wdt = platform_get_drvdata(pdev);
+
+	if (!nowayout)
+		bcm7038_wdt_stop(&wdt->wdd);
+
+	watchdog_unregister_device(&wdt->wdd);
+	clk_disable_unprepare(wdt->clk);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int bcm7038_wdt_suspend(struct device *dev)
+{
+	struct bcm7038_watchdog *wdt = dev_get_drvdata(dev);
+
+	if (watchdog_active(&wdt->wdd))
+		return bcm7038_wdt_stop(&wdt->wdd);
+
+	return 0;
+}
+
+static int bcm7038_wdt_resume(struct device *dev)
+{
+	struct bcm7038_watchdog *wdt = dev_get_drvdata(dev);
+
+	if (watchdog_active(&wdt->wdd))
+		return bcm7038_wdt_start(&wdt->wdd);
+
+	return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(bcm7038_wdt_pm_ops, bcm7038_wdt_suspend,
+			 bcm7038_wdt_resume);
+
+static void bcm7038_wdt_shutdown(struct platform_device *pdev)
+{
+	struct bcm7038_watchdog *wdt = platform_get_drvdata(pdev);
+
+	if (watchdog_active(&wdt->wdd))
+		bcm7038_wdt_stop(&wdt->wdd);
+}
+
+static const struct of_device_id bcm7038_wdt_match[] = {
+	{ .compatible = "brcm,bcm7038-wdt" },
+	{},
+};
+
+static struct platform_driver bcm7038_wdt_driver = {
+	.probe		= bcm7038_wdt_probe,
+	.remove		= bcm7038_wdt_remove,
+	.shutdown	= bcm7038_wdt_shutdown,
+	.driver		= {
+		.name		= "bcm7038-wdt",
+		.of_match_table	= bcm7038_wdt_match,
+		.pm		= &bcm7038_wdt_pm_ops,
+	}
+};
+module_platform_driver(bcm7038_wdt_driver);
+
+module_param(nowayout, bool, 0);
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
+	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Driver for Broadcom 7038 SoCs Watchdog");
+MODULE_AUTHOR("Justin Chen");

drivers/watchdog/imx2_wdt.c

@@ -91,7 +91,7 @@ static int imx2_restart_handler(struct notifier_block *this, unsigned long mode,
 						    struct imx2_wdt_device,
 						    restart_handler);
 	/* Assert SRS signal */
-	regmap_write(wdev->regmap, 0, wcr_enable);
+	regmap_write(wdev->regmap, IMX2_WDT_WCR, wcr_enable);
 	/*
 	 * Due to imx6q errata ERR004346 (WDOG: WDOG SRS bit requires to be
 	 * written twice), we add another two writes to ensure there must be at
@@ -99,8 +99,8 @@ static int imx2_restart_handler(struct notifier_block *this, unsigned long mode,
 	 * the target check here, since the writes shouldn't be a huge burden
 	 * for other platforms.
 	 */
-	regmap_write(wdev->regmap, 0, wcr_enable);
-	regmap_write(wdev->regmap, 0, wcr_enable);
+	regmap_write(wdev->regmap, IMX2_WDT_WCR, wcr_enable);
+	regmap_write(wdev->regmap, IMX2_WDT_WCR, wcr_enable);
 
 	/* wait for reset to assert... */
 	mdelay(500);

drivers/watchdog/intel-mid_wdt.c

@@ -101,7 +101,7 @@ static irqreturn_t mid_wdt_irq(int irq, void *dev_id)
 
 static const struct watchdog_info mid_wdt_info = {
 	.identity = "Intel MID SCU watchdog",
-	.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT,
+	.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
 };
 
 static const struct watchdog_ops mid_wdt_ops = {

drivers/watchdog/watchdog_core.c

@@ -139,7 +139,7 @@ EXPORT_SYMBOL_GPL(watchdog_init_timeout);
 
 static int __watchdog_register_device(struct watchdog_device *wdd)
 {
-	int ret, id, devno;
+	int ret, id = -1, devno;
 
 	if (wdd == NULL || wdd->info == NULL || wdd->ops == NULL)
 		return -EINVAL;
@@ -157,7 +157,18 @@ static int __watchdog_register_device(struct watchdog_device *wdd)
 	 */
 
 	mutex_init(&wdd->lock);
-	id = ida_simple_get(&watchdog_ida, 0, MAX_DOGS, GFP_KERNEL);
+
+	/* Use alias for watchdog id if possible */
+	if (wdd->parent) {
+		ret = of_alias_get_id(wdd->parent->of_node, "watchdog");
+		if (ret >= 0)
+			id = ida_simple_get(&watchdog_ida, ret,
+					    ret + 1, GFP_KERNEL);
+	}
+
+	if (id < 0)
+		id = ida_simple_get(&watchdog_ida, 0, MAX_DOGS, GFP_KERNEL);
+
 	if (id < 0)
 		return id;
 	wdd->id = id;

drivers/watchdog/watchdog_dev.c

@@ -51,7 +51,7 @@ static struct watchdog_device *old_wdd;
 
 /*
  *	watchdog_ping: ping the watchdog.
- *	@wddev: the watchdog device to ping
+ *	@wdd: the watchdog device to ping
  *
  *	If the watchdog has no own ping operation then it needs to be
  *	restarted via the start operation. This wrapper function does
@@ -59,65 +59,65 @@ static struct watchdog_device *old_wdd;
  *	We only ping when the watchdog device is running.
  */
 
-static int watchdog_ping(struct watchdog_device *wddev)
+static int watchdog_ping(struct watchdog_device *wdd)
 {
 	int err = 0;
 
-	mutex_lock(&wddev->lock);
+	mutex_lock(&wdd->lock);
 
-	if (test_bit(WDOG_UNREGISTERED, &wddev->status)) {
+	if (test_bit(WDOG_UNREGISTERED, &wdd->status)) {
 		err = -ENODEV;
 		goto out_ping;
 	}
 
-	if (!watchdog_active(wddev))
+	if (!watchdog_active(wdd))
 		goto out_ping;
 
-	if (wddev->ops->ping)
-		err = wddev->ops->ping(wddev);  /* ping the watchdog */
+	if (wdd->ops->ping)
+		err = wdd->ops->ping(wdd);	/* ping the watchdog */
 	else
-		err = wddev->ops->start(wddev); /* restart watchdog */
+		err = wdd->ops->start(wdd);	/* restart watchdog */
 
 out_ping:
-	mutex_unlock(&wddev->lock);
+	mutex_unlock(&wdd->lock);
 	return err;
 }
 
 /*
  *	watchdog_start: wrapper to start the watchdog.
- *	@wddev: the watchdog device to start
+ *	@wdd: the watchdog device to start
  *
  *	Start the watchdog if it is not active and mark it active.
  *	This function returns zero on success or a negative errno code for
  *	failure.
  */
 
-static int watchdog_start(struct watchdog_device *wddev)
+static int watchdog_start(struct watchdog_device *wdd)
 {
 	int err = 0;
 
-	mutex_lock(&wddev->lock);
+	mutex_lock(&wdd->lock);
 
-	if (test_bit(WDOG_UNREGISTERED, &wddev->status)) {
+	if (test_bit(WDOG_UNREGISTERED, &wdd->status)) {
 		err = -ENODEV;
 		goto out_start;
 	}
 
-	if (watchdog_active(wddev))
+	if (watchdog_active(wdd))
 		goto out_start;
 
-	err = wddev->ops->start(wddev);
+	err = wdd->ops->start(wdd);
 	if (err == 0)
-		set_bit(WDOG_ACTIVE, &wddev->status);
+		set_bit(WDOG_ACTIVE, &wdd->status);
 
 out_start:
-	mutex_unlock(&wddev->lock);
+	mutex_unlock(&wdd->lock);
 	return err;
 }
 
 /*
  *	watchdog_stop: wrapper to stop the watchdog.
- *	@wddev: the watchdog device to stop
+ *	@wdd: the watchdog device to stop
  *
  *	Stop the watchdog if it is still active and unmark it active.
  *	This function returns zero on success or a negative errno code for
@@ -125,155 +125,154 @@ out_start:
  *	If the 'nowayout' feature was set, the watchdog cannot be stopped.
  */
 
-static int watchdog_stop(struct watchdog_device *wddev)
+static int watchdog_stop(struct watchdog_device *wdd)
 {
 	int err = 0;
 
-	mutex_lock(&wddev->lock);
+	mutex_lock(&wdd->lock);
 
-	if (test_bit(WDOG_UNREGISTERED, &wddev->status)) {
+	if (test_bit(WDOG_UNREGISTERED, &wdd->status)) {
 		err = -ENODEV;
 		goto out_stop;
 	}
 
-	if (!watchdog_active(wddev))
+	if (!watchdog_active(wdd))
 		goto out_stop;
 
-	if (test_bit(WDOG_NO_WAY_OUT, &wddev->status)) {
-		dev_info(wddev->dev, "nowayout prevents watchdog being stopped!\n");
+	if (test_bit(WDOG_NO_WAY_OUT, &wdd->status)) {
+		dev_info(wdd->dev, "nowayout prevents watchdog being stopped!\n");
 		err = -EBUSY;
 		goto out_stop;
 	}
 
-	err = wddev->ops->stop(wddev);
+	err = wdd->ops->stop(wdd);
 	if (err == 0)
-		clear_bit(WDOG_ACTIVE, &wddev->status);
+		clear_bit(WDOG_ACTIVE, &wdd->status);
 
 out_stop:
-	mutex_unlock(&wddev->lock);
+	mutex_unlock(&wdd->lock);
 	return err;
 }
 
 /*
  *	watchdog_get_status: wrapper to get the watchdog status
- *	@wddev: the watchdog device to get the status from
+ *	@wdd: the watchdog device to get the status from
  *	@status: the status of the watchdog device
  *
  *	Get the watchdog's status flags.
  */
 
-static int watchdog_get_status(struct watchdog_device *wddev,
+static int watchdog_get_status(struct watchdog_device *wdd,
 							unsigned int *status)
 {
 	int err = 0;
 
 	*status = 0;
-	if (!wddev->ops->status)
+	if (!wdd->ops->status)
 		return -EOPNOTSUPP;
 
-	mutex_lock(&wddev->lock);
+	mutex_lock(&wdd->lock);
 
-	if (test_bit(WDOG_UNREGISTERED, &wddev->status)) {
+	if (test_bit(WDOG_UNREGISTERED, &wdd->status)) {
 		err = -ENODEV;
 		goto out_status;
 	}
 
-	*status = wddev->ops->status(wddev);
+	*status = wdd->ops->status(wdd);
 
 out_status:
-	mutex_unlock(&wddev->lock);
+	mutex_unlock(&wdd->lock);
 	return err;
 }
 
 /*
  *	watchdog_set_timeout: set the watchdog timer timeout
- *	@wddev: the watchdog device to set the timeout for
+ *	@wdd: the watchdog device to set the timeout for
  *	@timeout: timeout to set in seconds
  */
 
-static int watchdog_set_timeout(struct watchdog_device *wddev,
+static int watchdog_set_timeout(struct watchdog_device *wdd,
 							unsigned int timeout)
 {
 	int err;
 
-	if ((wddev->ops->set_timeout == NULL) ||
-	    !(wddev->info->options & WDIOF_SETTIMEOUT))
+	if (!wdd->ops->set_timeout || !(wdd->info->options & WDIOF_SETTIMEOUT))
 		return -EOPNOTSUPP;
 
-	if (watchdog_timeout_invalid(wddev, timeout))
+	if (watchdog_timeout_invalid(wdd, timeout))
 		return -EINVAL;
 
-	mutex_lock(&wddev->lock);
+	mutex_lock(&wdd->lock);
 
-	if (test_bit(WDOG_UNREGISTERED, &wddev->status)) {
+	if (test_bit(WDOG_UNREGISTERED, &wdd->status)) {
 		err = -ENODEV;
 		goto out_timeout;
 	}
 
-	err = wddev->ops->set_timeout(wddev, timeout);
+	err = wdd->ops->set_timeout(wdd, timeout);
 
 out_timeout:
-	mutex_unlock(&wddev->lock);
+	mutex_unlock(&wdd->lock);
 	return err;
 }
 
 /*
  *	watchdog_get_timeleft: wrapper to get the time left before a reboot
- *	@wddev: the watchdog device to get the remaining time from
+ *	@wdd: the watchdog device to get the remaining time from
  *	@timeleft: the time that's left
  *
  *	Get the time before a watchdog will reboot (if not pinged).
  */
 
-static int watchdog_get_timeleft(struct watchdog_device *wddev,
+static int watchdog_get_timeleft(struct watchdog_device *wdd,
 							unsigned int *timeleft)
 {
 	int err = 0;
 
 	*timeleft = 0;
-	if (!wddev->ops->get_timeleft)
+	if (!wdd->ops->get_timeleft)
 		return -EOPNOTSUPP;
 
-	mutex_lock(&wddev->lock);
+	mutex_lock(&wdd->lock);
 
-	if (test_bit(WDOG_UNREGISTERED, &wddev->status)) {
+	if (test_bit(WDOG_UNREGISTERED, &wdd->status)) {
 		err = -ENODEV;
 		goto out_timeleft;
 	}
 
-	*timeleft = wddev->ops->get_timeleft(wddev);
+	*timeleft = wdd->ops->get_timeleft(wdd);
 
 out_timeleft:
-	mutex_unlock(&wddev->lock);
+	mutex_unlock(&wdd->lock);
 	return err;
 }
 
 /*
  *	watchdog_ioctl_op: call the watchdog drivers ioctl op if defined
- *	@wddev: the watchdog device to do the ioctl on
+ *	@wdd: the watchdog device to do the ioctl on
  *	@cmd: watchdog command
  *	@arg: argument pointer
  */
 
-static int watchdog_ioctl_op(struct watchdog_device *wddev, unsigned int cmd,
+static int watchdog_ioctl_op(struct watchdog_device *wdd, unsigned int cmd,
 							unsigned long arg)
 {
 	int err;
 
-	if (!wddev->ops->ioctl)
+	if (!wdd->ops->ioctl)
 		return -ENOIOCTLCMD;
 
-	mutex_lock(&wddev->lock);
+	mutex_lock(&wdd->lock);
 
-	if (test_bit(WDOG_UNREGISTERED, &wddev->status)) {
+	if (test_bit(WDOG_UNREGISTERED, &wdd->status)) {
 		err = -ENODEV;
 		goto out_ioctl;
 	}
 
-	err = wddev->ops->ioctl(wddev, cmd, arg);
+	err = wdd->ops->ioctl(wdd, cmd, arg);
 
 out_ioctl:
-	mutex_unlock(&wddev->lock);
+	mutex_unlock(&wdd->lock);
 	return err;
 }
 
@@ -295,6 +294,7 @@ static ssize_t watchdog_write(struct file *file, const char __user *data,
 	struct watchdog_device *wdd = file->private_data;
 	size_t i;
 	char c;
+	int err;
 
 	if (len == 0)
 		return 0;
@@ -314,7 +314,9 @@ static ssize_t watchdog_write(struct file *file, const char __user *data,
 	}
 
 	/* someone wrote to us, so we send the watchdog a keepalive ping */
-	watchdog_ping(wdd);
+	err = watchdog_ping(wdd);
+	if (err < 0)
+		return err;
 
 	return len;
 }
@@ -370,8 +372,7 @@ static long watchdog_ioctl(struct file *file, unsigned int cmd,
 	case WDIOC_KEEPALIVE:
 		if (!(wdd->info->options & WDIOF_KEEPALIVEPING))
 			return -EOPNOTSUPP;
-		watchdog_ping(wdd);
-		return 0;
+		return watchdog_ping(wdd);
 	case WDIOC_SETTIMEOUT:
 		if (get_user(val, p))
 			return -EFAULT;
@@ -381,7 +382,9 @@ static long watchdog_ioctl(struct file *file, unsigned int cmd,
 		/* If the watchdog is active then we send a keepalive ping
 		 * to make sure that the watchdog keep's running (and if
 		 * possible that it takes the new timeout) */
-		watchdog_ping(wdd);
+		err = watchdog_ping(wdd);
+		if (err < 0)
+			return err;
 		/* Fall */
 	case WDIOC_GETTIMEOUT:
 		/* timeout == 0 means that we don't know the timeout */
@@ -513,43 +516,43 @@ static struct miscdevice watchdog_miscdev = {
 
 /*
  *	watchdog_dev_register: register a watchdog device
- *	@watchdog: watchdog device
+ *	@wdd: watchdog device
  *
  *	Register a watchdog device including handling the legacy
  *	/dev/watchdog node. /dev/watchdog is actually a miscdevice and
  *	thus we set it up like that.
  */
 
-int watchdog_dev_register(struct watchdog_device *watchdog)
+int watchdog_dev_register(struct watchdog_device *wdd)
 {
 	int err, devno;
 
-	if (watchdog->id == 0) {
-		old_wdd = watchdog;
-		watchdog_miscdev.parent = watchdog->parent;
+	if (wdd->id == 0) {
+		old_wdd = wdd;
+		watchdog_miscdev.parent = wdd->parent;
 		err = misc_register(&watchdog_miscdev);
 		if (err != 0) {
 			pr_err("%s: cannot register miscdev on minor=%d (err=%d).\n",
-				watchdog->info->identity, WATCHDOG_MINOR, err);
+				wdd->info->identity, WATCHDOG_MINOR, err);
 			if (err == -EBUSY)
 				pr_err("%s: a legacy watchdog module is probably present.\n",
-					watchdog->info->identity);
+					wdd->info->identity);
 			old_wdd = NULL;
 			return err;
 		}
 	}
 
 	/* Fill in the data structures */
-	devno = MKDEV(MAJOR(watchdog_devt), watchdog->id);
-	cdev_init(&watchdog->cdev, &watchdog_fops);
-	watchdog->cdev.owner = watchdog->ops->owner;
+	devno = MKDEV(MAJOR(watchdog_devt), wdd->id);
+	cdev_init(&wdd->cdev, &watchdog_fops);
+	wdd->cdev.owner = wdd->ops->owner;
 
 	/* Add the device */
-	err  = cdev_add(&watchdog->cdev, devno, 1);
+	err  = cdev_add(&wdd->cdev, devno, 1);
 	if (err) {
 		pr_err("watchdog%d unable to add device %d:%d\n",
-			watchdog->id,  MAJOR(watchdog_devt), watchdog->id);
-		if (watchdog->id == 0) {
+			wdd->id,  MAJOR(watchdog_devt), wdd->id);
+		if (wdd->id == 0) {
 			misc_deregister(&watchdog_miscdev);
 			old_wdd = NULL;
 		}
@@ -564,14 +567,14 @@ int watchdog_dev_register(struct watchdog_device *watchdog)
  *	Unregister the watchdog and if needed the legacy /dev/watchdog device.
  */
 
-int watchdog_dev_unregister(struct watchdog_device *watchdog)
+int watchdog_dev_unregister(struct watchdog_device *wdd)
 {
-	mutex_lock(&watchdog->lock);
-	set_bit(WDOG_UNREGISTERED, &watchdog->status);
-	mutex_unlock(&watchdog->lock);
+	mutex_lock(&wdd->lock);
+	set_bit(WDOG_UNREGISTERED, &wdd->status);
+	mutex_unlock(&wdd->lock);
 
-	cdev_del(&watchdog->cdev);
-	if (watchdog->id == 0) {
+	cdev_del(&wdd->cdev);
+	if (wdd->id == 0) {
 		misc_deregister(&watchdog_miscdev);
 		old_wdd = NULL;
 	}

include/linux/watchdog.h

@@ -24,8 +24,8 @@ struct watchdog_device;
  * @stop:	The routine for stopping the watchdog device.
  * @ping:	The routine that sends a keepalive ping to the watchdog device.
  * @status:	The routine that shows the status of the watchdog device.
- * @set_timeout:The routine for setting the watchdog devices timeout value.
- * @get_timeleft:The routine that get's the time that's left before a reset.
+ * @set_timeout:The routine for setting the watchdog devices timeout value (in seconds).
+ * @get_timeleft:The routine that gets the time left before a reset (in seconds).
  * @ref:	The ref operation for dyn. allocated watchdog_device structs
  * @unref:	The unref operation for dyn. allocated watchdog_device structs
  * @ioctl:	The routines that handles extra ioctl calls.
@@ -33,7 +33,7 @@ struct watchdog_device;
  * The watchdog_ops structure contains a list of low-level operations
  * that control a watchdog device. It also contains the module that owns
  * these operations. The start and stop function are mandatory, all other
- * functions are optonal.
+ * functions are optional.
  */
 struct watchdog_ops {
 	struct module *owner;
@@ -59,9 +59,9 @@ struct watchdog_ops {
  * @info:	Pointer to a watchdog_info structure.
  * @ops:	Pointer to the list of watchdog operations.
  * @bootstatus:	Status of the watchdog device at boot.
- * @timeout:	The watchdog devices timeout value.
- * @min_timeout:The watchdog devices minimum timeout value.
- * @max_timeout:The watchdog devices maximum timeout value.
+ * @timeout:	The watchdog devices timeout value (in seconds).
+ * @min_timeout:The watchdog devices minimum timeout value (in seconds).
+ * @max_timeout:The watchdog devices maximum timeout value (in seconds).
  * @driver-data:Pointer to the drivers private data.
  * @lock:	Lock for watchdog core internal use only.
  * @status:	Field that contains the devices internal status bits.
@@ -119,8 +119,15 @@ static inline void watchdog_set_nowayout(struct watchdog_device *wdd, bool noway
 /* Use the following function to check if a timeout value is invalid */
 static inline bool watchdog_timeout_invalid(struct watchdog_device *wdd, unsigned int t)
 {
-	return ((wdd->max_timeout != 0) &&
-		(t < wdd->min_timeout || t > wdd->max_timeout));
+	/*
+	 * The timeout is invalid if
+	 * - the requested value is smaller than the configured minimum timeout,
+	 * or
+	 * - a maximum timeout is configured, and the requested value is larger
+	 *   than the maximum timeout.
+	 */
+	return t < wdd->min_timeout ||
+		(wdd->max_timeout && t > wdd->max_timeout);
 }
 
 /* Use the following functions to manipulate watchdog driver specific data */