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

9 files changed, 380 insertions, 94 deletions

diff --git a/Documentation/devicetree/bindings/watchdog/brcm,bcm7038-wdt.txt b/Documentation/devicetree/bindings/watchdog/brcm,bcm7038-wdt.txt
new file mode 100644
index 000000000000..84122270be8f
--- /dev/null
+++ b/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>;
+};
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 79e1aa1b0959..7a8a6c6952e9 100644
--- a/drivers/watchdog/Kconfig
+++ b/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
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 0c616e3f67bb..53d4827ddfe1 100644
--- a/drivers/watchdog/Makefile
+++ b/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
diff --git a/drivers/watchdog/bcm7038_wdt.c b/drivers/watchdog/bcm7038_wdt.c
new file mode 100644
index 000000000000..4245b65d645c
--- /dev/null
+++ b/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");
diff --git a/drivers/watchdog/imx2_wdt.c b/drivers/watchdog/imx2_wdt.c
index 0bb1a1d1b170..29ef719a6a3c 100644
--- a/drivers/watchdog/imx2_wdt.c
+++ b/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);
diff --git a/drivers/watchdog/intel-mid_wdt.c b/drivers/watchdog/intel-mid_wdt.c
index 0a436b5d1e84..db36d12e2b52 100644
--- a/drivers/watchdog/intel-mid_wdt.c
+++ b/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 = {
diff --git a/drivers/watchdog/watchdog_core.c b/drivers/watchdog/watchdog_core.c
index 1a8059455413..873f13972cf4 100644
--- a/drivers/watchdog/watchdog_core.c
+++ b/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;
diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c
index 6aaefbad303e..56a649e66eb2 100644
--- a/drivers/watchdog/watchdog_dev.c
+++ b/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;
         }
diff --git a/include/linux/watchdog.h b/include/linux/watchdog.h
index d74a0e907b9e..027b1f43f12d 100644
--- a/include/linux/watchdog.h
+++ b/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 */