[PATCH] watchdog: imx2_wdt: convert to watchdog core api

[PATCH] watchdog: imx2_wdt: convert to watchdog core api

[Anatolij Gustschin]

Convert the imx2_wdt driver to the new watchdog core api.

Signed-off-by: Anatolij Gustschin <agust@denx.de>
Cc: Wolfram Sang <wsa@the-dreams.de>
Cc: Wim Van Sebroeck <wim@iguana.be>
---
NOTE: This patch applies on top of the imx2_wdt regmap-mmio support
patch series http://comments.gmane.org/gmane.linux.kernel/1677735

 drivers/watchdog/Kconfig    |    1 +
 drivers/watchdog/imx2_wdt.c |  292 ++++++++++++++++++-------------------------
 2 files changed, 124 insertions(+), 169 deletions(-)

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index e1ff4f1..3f14031 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -379,6 +379,7 @@ config IMX2_WDT
 	tristate "IMX2+ Watchdog"
 	depends on ARCH_MXC
 	select REGMAP_MMIO
+	select WATCHDOG_CORE
 	help
 	  This is the driver for the hardware watchdog
 	  on the Freescale IMX2 and later processors.
diff --git a/drivers/watchdog/imx2_wdt.c b/drivers/watchdog/imx2_wdt.c
index 76fa724..c080b76 100644
--- a/drivers/watchdog/imx2_wdt.c
+++ b/drivers/watchdog/imx2_wdt.c
@@ -22,18 +22,15 @@
  */
 
 #include <linux/clk.h>
-#include <linux/fs.h>
 #include <linux/init.h>
 #include <linux/io.h>
 #include <linux/jiffies.h>
 #include <linux/kernel.h>
-#include <linux/miscdevice.h>
 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/platform_device.h>
 #include <linux/regmap.h>
 #include <linux/timer.h>
-#include <linux/uaccess.h>
 #include <linux/watchdog.h>
 
 #define DRIVER_NAME "imx2-wdt"
@@ -56,19 +53,12 @@
 
 #define WDOG_SEC_TO_COUNT(s)	((s * 2 - 1) << 8)
 
-#define IMX2_WDT_STATUS_OPEN	0
-#define IMX2_WDT_STATUS_STARTED	1
-#define IMX2_WDT_EXPECT_CLOSE	2
-
-static struct {
+struct imx2_wdt_device {
 	struct clk *clk;
 	struct regmap *regmap;
-	unsigned timeout;
-	unsigned long status;
 	struct timer_list timer;	/* Pings the watchdog when closed */
-} imx2_wdt;
-
-static struct miscdevice imx2_wdt_miscdev;
+	struct watchdog_device wdog;
+};
 
 static bool nowayout = WATCHDOG_NOWAYOUT;
 module_param(nowayout, bool, 0);
@@ -86,11 +76,12 @@ static const struct watchdog_info imx2_wdt_info = {
 	.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
 };
 
-static inline void imx2_wdt_setup(void)
+static inline void imx2_wdt_setup(struct watchdog_device *wdog)
 {
+	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
 	u32 val;
 
-	regmap_read(imx2_wdt.regmap, IMX2_WDT_WCR, &val);
+	regmap_read(wdev->regmap, IMX2_WDT_WCR, &val);
 
 	/* Suspend timer in low power mode, write once-only */
 	val |= IMX2_WDT_WCR_WDZST;
@@ -101,157 +92,95 @@ static inline void imx2_wdt_setup(void)
 	/* Keep Watchdog Disabled */
 	val &= ~IMX2_WDT_WCR_WDE;
 	/* Set the watchdog's Time-Out value */
-	val |= WDOG_SEC_TO_COUNT(imx2_wdt.timeout);
+	val |= WDOG_SEC_TO_COUNT(wdog->timeout);
 
-	regmap_write(imx2_wdt.regmap, IMX2_WDT_WCR, val);
+	regmap_write(wdev->regmap, IMX2_WDT_WCR, val);
 
 	/* enable the watchdog */
 	val |= IMX2_WDT_WCR_WDE;
-	regmap_write(imx2_wdt.regmap, IMX2_WDT_WCR, val);
+	regmap_write(wdev->regmap, IMX2_WDT_WCR, val);
 }
 
-static inline void imx2_wdt_ping(void)
+static inline bool imx2_wdt_is_running(struct imx2_wdt_device *wdev)
 {
-	regmap_write(imx2_wdt.regmap, IMX2_WDT_WSR, IMX2_WDT_SEQ1);
-	regmap_write(imx2_wdt.regmap, IMX2_WDT_WSR, IMX2_WDT_SEQ2);
-}
+	u32 val;
 
-static void imx2_wdt_timer_ping(unsigned long arg)
-{
-	/* ping it every imx2_wdt.timeout / 2 seconds to prevent reboot */
-	imx2_wdt_ping();
-	mod_timer(&imx2_wdt.timer, jiffies + imx2_wdt.timeout * HZ / 2);
+	regmap_read(wdev->regmap, IMX2_WDT_WCR, &val);
+
+	if (val & IMX2_WDT_WCR_WDE)
+		return true;
+	return false;
 }
 
-static void imx2_wdt_start(void)
+static int imx2_wdt_ping(struct watchdog_device *wdog)
 {
-	if (!test_and_set_bit(IMX2_WDT_STATUS_STARTED, &imx2_wdt.status)) {
-		/* at our first start we enable clock and do initialisations */
-		clk_prepare_enable(imx2_wdt.clk);
-
-		imx2_wdt_setup();
-	} else	/* delete the timer that pings the watchdog after close */
-		del_timer_sync(&imx2_wdt.timer);
+	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
 
-	/* Watchdog is enabled - time to reload the timeout value */
-	imx2_wdt_ping();
+	regmap_write(wdev->regmap, IMX2_WDT_WSR, IMX2_WDT_SEQ1);
+	regmap_write(wdev->regmap, IMX2_WDT_WSR, IMX2_WDT_SEQ2);
+	return 0;
 }
 
-static void imx2_wdt_stop(void)
+static void imx2_wdt_timer_ping(unsigned long arg)
 {
-	/* we don't need a clk_disable, it cannot be disabled once started.
-	 * We use a timer to ping the watchdog while /dev/watchdog is closed */
-	imx2_wdt_timer_ping(0);
+	struct watchdog_device *wdog = (struct watchdog_device *)arg;
+	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
+
+	/* ping it every wdog->timeout / 2 seconds to prevent reboot */
+	imx2_wdt_ping(wdog);
+	mod_timer(&wdev->timer, jiffies + wdog->timeout * HZ / 2);
 }
 
-static void imx2_wdt_set_timeout(int new_timeout)
+static int imx2_wdt_set_timeout(struct watchdog_device *wdog,
+				unsigned int new_timeout)
 {
-	regmap_update_bits(imx2_wdt.regmap, IMX2_WDT_WCR, IMX2_WDT_WCR_WT,
+	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
+
+	regmap_update_bits(wdev->regmap, IMX2_WDT_WCR, IMX2_WDT_WCR_WT,
 			   WDOG_SEC_TO_COUNT(new_timeout));
+	return 0;
 }
 
-static int imx2_wdt_open(struct inode *inode, struct file *file)
+static int imx2_wdt_start(struct watchdog_device *wdog)
 {
-	if (test_and_set_bit(IMX2_WDT_STATUS_OPEN, &imx2_wdt.status))
-		return -EBUSY;
+	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
 
-	imx2_wdt_start();
-	return nonseekable_open(inode, file);
+	if (imx2_wdt_is_running(wdev)) {
+		/* delete the timer that pings the watchdog after close */
+		del_timer_sync(&wdev->timer);
+		imx2_wdt_set_timeout(wdog, wdog->timeout);
+	} else
+		imx2_wdt_setup(wdog);
+
+	return imx2_wdt_ping(wdog);
 }
 
-static int imx2_wdt_close(struct inode *inode, struct file *file)
+static int imx2_wdt_stop(struct watchdog_device *wdog)
 {
-	if (test_bit(IMX2_WDT_EXPECT_CLOSE, &imx2_wdt.status) && !nowayout)
-		imx2_wdt_stop();
-	else {
-		dev_crit(imx2_wdt_miscdev.parent,
-			"Unexpected close: Expect reboot!\n");
-		imx2_wdt_ping();
-	}
-
-	clear_bit(IMX2_WDT_EXPECT_CLOSE, &imx2_wdt.status);
-	clear_bit(IMX2_WDT_STATUS_OPEN, &imx2_wdt.status);
+	/*
+	 * We don't need a clk_disable, it cannot be disabled once started.
+	 * We use a timer to ping the watchdog while /dev/watchdog is closed
+	 */
+	imx2_wdt_timer_ping((unsigned long)wdog);
 	return 0;
 }
 
-static long imx2_wdt_ioctl(struct file *file, unsigned int cmd,
-							unsigned long arg)
+static inline void imx2_wdt_ping_if_active(struct watchdog_device *wdog)
 {
-	void __user *argp = (void __user *)arg;
-	int __user *p = argp;
-	int new_value;
-	u32 val;
+	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
 
-	switch (cmd) {
-	case WDIOC_GETSUPPORT:
-		return copy_to_user(argp, &imx2_wdt_info,
-			sizeof(struct watchdog_info)) ? -EFAULT : 0;
-
-	case WDIOC_GETSTATUS:
-		return put_user(0, p);
-
-	case WDIOC_GETBOOTSTATUS:
-		regmap_read(imx2_wdt.regmap, IMX2_WDT_WRSR, &val);
-		new_value = val & IMX2_WDT_WRSR_TOUT ? WDIOF_CARDRESET : 0;
-		return put_user(new_value, p);
-
-	case WDIOC_KEEPALIVE:
-		imx2_wdt_ping();
-		return 0;
-
-	case WDIOC_SETTIMEOUT:
-		if (get_user(new_value, p))
-			return -EFAULT;
-		if ((new_value < 1) || (new_value > IMX2_WDT_MAX_TIME))
-			return -EINVAL;
-		imx2_wdt_set_timeout(new_value);
-		imx2_wdt.timeout = new_value;
-		imx2_wdt_ping();
-
-		/* Fallthrough to return current value */
-	case WDIOC_GETTIMEOUT:
-		return put_user(imx2_wdt.timeout, p);
-
-	default:
-		return -ENOTTY;
+	if (imx2_wdt_is_running(wdev)) {
+		imx2_wdt_set_timeout(wdog, wdog->timeout);
+		imx2_wdt_timer_ping((unsigned long)wdog);
 	}
 }
 
-static ssize_t imx2_wdt_write(struct file *file, const char __user *data,
-						size_t len, loff_t *ppos)
-{
-	size_t i;
-	char c;
-
-	if (len == 0)	/* Can we see this even ? */
-		return 0;
-
-	clear_bit(IMX2_WDT_EXPECT_CLOSE, &imx2_wdt.status);
-	/* scan to see whether or not we got the magic character */
-	for (i = 0; i != len; i++) {
-		if (get_user(c, data + i))
-			return -EFAULT;
-		if (c == 'V')
-			set_bit(IMX2_WDT_EXPECT_CLOSE, &imx2_wdt.status);
-	}
-
-	imx2_wdt_ping();
-	return len;
-}
-
-static const struct file_operations imx2_wdt_fops = {
+static struct watchdog_ops imx2_wdt_ops = {
 	.owner = THIS_MODULE,
-	.llseek = no_llseek,
-	.unlocked_ioctl = imx2_wdt_ioctl,
-	.open = imx2_wdt_open,
-	.release = imx2_wdt_close,
-	.write = imx2_wdt_write,
-};
-
-static struct miscdevice imx2_wdt_miscdev = {
-	.minor = WATCHDOG_MINOR,
-	.name = "watchdog",
-	.fops = &imx2_wdt_fops,
+	.start = imx2_wdt_start,
+	.stop = imx2_wdt_stop,
+	.ping = imx2_wdt_ping,
+	.set_timeout = imx2_wdt_set_timeout,
 };
 
 static struct regmap_config imx2_wdt_regmap_config = {
@@ -263,76 +192,101 @@ static struct regmap_config imx2_wdt_regmap_config = {
 
 static int __init imx2_wdt_probe(struct platform_device *pdev)
 {
+	struct imx2_wdt_device *wdev;
+	struct watchdog_device *wdog;
 	struct resource *res;
 	void __iomem *base;
 	int ret;
+	u32 val;
+
+	wdev = devm_kzalloc(&pdev->dev, sizeof(*wdev), GFP_KERNEL);
+	if (!wdev)
+		return -ENOMEM;
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	base = devm_ioremap_resource(&pdev->dev, res);
 	if (IS_ERR(base))
 		return PTR_ERR(base);
 
-	imx2_wdt.regmap = devm_regmap_init_mmio_clk(&pdev->dev, NULL, base,
-						    &imx2_wdt_regmap_config);
-	if (IS_ERR(imx2_wdt.regmap)) {
+	wdev->regmap = devm_regmap_init_mmio_clk(&pdev->dev, NULL, base,
+						 &imx2_wdt_regmap_config);
+	if (IS_ERR(wdev->regmap)) {
 		dev_err(&pdev->dev, "regmap init failed\n");
-		return PTR_ERR(imx2_wdt.regmap);
+		return PTR_ERR(wdev->regmap);
 	}
 
-	imx2_wdt.clk = devm_clk_get(&pdev->dev, NULL);
-	if (IS_ERR(imx2_wdt.clk)) {
+	wdev->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(wdev->clk)) {
 		dev_err(&pdev->dev, "can't get Watchdog clock\n");
-		return PTR_ERR(imx2_wdt.clk);
+		return PTR_ERR(wdev->clk);
 	}
 
-	imx2_wdt.timeout = clamp_t(unsigned, timeout, 1, IMX2_WDT_MAX_TIME);
-	if (imx2_wdt.timeout != timeout)
+	wdog			= &wdev->wdog;
+	wdog->info		= &imx2_wdt_info;
+	wdog->ops		= &imx2_wdt_ops;
+	wdog->min_timeout	= 1;
+	wdog->max_timeout	= IMX2_WDT_MAX_TIME;
+
+	clk_prepare_enable(wdev->clk);
+
+	regmap_read(wdev->regmap, IMX2_WDT_WRSR, &val);
+	wdog->bootstatus = val & IMX2_WDT_WRSR_TOUT ? WDIOF_CARDRESET : 0;
+
+	wdog->timeout = clamp_t(unsigned, timeout, 1, IMX2_WDT_MAX_TIME);
+	if (wdog->timeout != timeout)
 		dev_warn(&pdev->dev, "Initial timeout out of range! "
-			"Clamped from %u to %u\n", timeout, imx2_wdt.timeout);
+			"Clamped from %u to %u\n", timeout, wdog->timeout);
 
-	setup_timer(&imx2_wdt.timer, imx2_wdt_timer_ping, 0);
+	platform_set_drvdata(pdev, wdog);
+	watchdog_set_drvdata(wdog, wdev);
+	watchdog_set_nowayout(wdog, nowayout);
+	watchdog_init_timeout(wdog, timeout, &pdev->dev);
 
-	imx2_wdt_miscdev.parent = &pdev->dev;
-	ret = misc_register(&imx2_wdt_miscdev);
-	if (ret)
-		goto fail;
+	setup_timer(&wdev->timer, imx2_wdt_timer_ping, (unsigned long)wdog);
 
-	dev_info(&pdev->dev,
-		"IMX2+ Watchdog Timer enabled. timeout=%ds (nowayout=%d)\n",
-						imx2_wdt.timeout, nowayout);
-	return 0;
+	imx2_wdt_ping_if_active(wdog);
 
-fail:
-	imx2_wdt_miscdev.parent = NULL;
-	return ret;
+	ret = watchdog_register_device(wdog);
+	if (ret) {
+		dev_err(&pdev->dev, "cannot register watchdog device\n");
+		return ret;
+	}
+
+	dev_info(&pdev->dev, "timeout %d sec (nowayout=%d)\n",
+		 wdog->timeout, nowayout);
+
+	return 0;
 }
 
 static int __exit imx2_wdt_remove(struct platform_device *pdev)
 {
-	misc_deregister(&imx2_wdt_miscdev);
+	struct watchdog_device *wdog = platform_get_drvdata(pdev);
+	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
 
-	if (test_bit(IMX2_WDT_STATUS_STARTED, &imx2_wdt.status)) {
-		del_timer_sync(&imx2_wdt.timer);
+	watchdog_unregister_device(wdog);
 
-		dev_crit(imx2_wdt_miscdev.parent,
-			"Device removed: Expect reboot!\n");
+	if (imx2_wdt_is_running(wdev)) {
+		del_timer_sync(&wdev->timer);
+		imx2_wdt_ping(wdog);
+		dev_crit(&pdev->dev, "Device removed: Expect reboot!\n");
 	}
-
-	imx2_wdt_miscdev.parent = NULL;
 	return 0;
 }
 
 static void imx2_wdt_shutdown(struct platform_device *pdev)
 {
-	if (test_bit(IMX2_WDT_STATUS_STARTED, &imx2_wdt.status)) {
-		/* we are running, we need to delete the timer but will give
-		 * max timeout before reboot will take place */
-		del_timer_sync(&imx2_wdt.timer);
-		imx2_wdt_set_timeout(IMX2_WDT_MAX_TIME);
-		imx2_wdt_ping();
-
-		dev_crit(imx2_wdt_miscdev.parent,
-			"Device shutdown: Expect reboot!\n");
+	struct watchdog_device *wdog = platform_get_drvdata(pdev);
+	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
+
+	if (imx2_wdt_is_running(wdev)) {
+		/*
+		 * We are running, we need to delete the timer but will
+		 * give max timeout before reboot will take place
+		 */
+		del_timer_sync(&wdev->timer);
+		imx2_wdt_set_timeout(wdog, IMX2_WDT_MAX_TIME);
+		imx2_wdt_ping(wdog);
+		dev_crit(&pdev->dev, "Device shutdown: Expect reboot!\n");
 	}
 }
 
-- 
1.7.9.5

[PATCH] watchdog: imx2_wdt: convert to watchdog core api

[Guenter Roeck]

On Sat, Apr 05, 2014 at 08:29:40PM +0200, Anatolij Gustschin wrote:
> Convert the imx2_wdt driver to the new watchdog core api.
> 
> Signed-off-by: Anatolij Gustschin <agust@denx.de>
> Cc: Wolfram Sang <wsa@the-dreams.de>
> Cc: Wim Van Sebroeck <wim@iguana.be>

Looks pretty good, just a couple of nitpicks.

> ---
> NOTE: This patch applies on top of the imx2_wdt regmap-mmio support
> patch series http://comments.gmane.org/gmane.linux.kernel/1677735
> 
>  drivers/watchdog/Kconfig    |    1 +
>  drivers/watchdog/imx2_wdt.c |  292 ++++++++++++++++++-------------------------
>  2 files changed, 124 insertions(+), 169 deletions(-)
>  
[ ... ]

> -static void imx2_wdt_timer_ping(unsigned long arg)
> -{
> -	/* ping it every imx2_wdt.timeout / 2 seconds to prevent reboot */
> -	imx2_wdt_ping();
> -	mod_timer(&imx2_wdt.timer, jiffies + imx2_wdt.timeout * HZ / 2);
> +	regmap_read(wdev->regmap, IMX2_WDT_WCR, &val);
> +
> +	if (val & IMX2_WDT_WCR_WDE)
> +		return true;
> +	return false;
>  }

You can simplyfy this to

	return val & IMX2_WDT_WCR_WDE;

since C auto-converts from int to bool. If you feel fancy and don't
trust the C compiler, another option would be

	return !!(val & IMX2_WDT_WCR_WDE);

which would at least drop the if statement.

[ ... ]

> +
> +	wdog->timeout = clamp_t(unsigned, timeout, 1, IMX2_WDT_MAX_TIME);
> +	if (wdog->timeout != timeout)
>  		dev_warn(&pdev->dev, "Initial timeout out of range! "
> -			"Clamped from %u to %u\n", timeout, imx2_wdt.timeout);
> +			"Clamped from %u to %u\n", timeout, wdog->timeout);

Somewhat unrelated, but this results in a checkpatch warning.
I would suggest to put the string in a single line.

		dev_warn(&pdev->dev,
			 "Initial timeout out of range! Clamped from %u to %u\n",
			 timeout, wdog->timeout);

Guenter

[PATCH] watchdog: imx2_wdt: convert to watchdog core api

[Anatolij Gustschin]

On Mon, 7 Apr 2014 09:48:11 -0700
Guenter Roeck <linux@roeck-us.net> wrote:
...
> > +	if (val & IMX2_WDT_WCR_WDE)
> > +		return true;
> > +	return false;
> >  }
> 
> You can simplyfy this to
> 
> 	return val & IMX2_WDT_WCR_WDE;
> 
> since C auto-converts from int to bool. If you feel fancy and don't
> trust the C compiler, another option would be
> 
> 	return !!(val & IMX2_WDT_WCR_WDE);
> 
> which would at least drop the if statement.

I'll simplify it, yes.

> [ ... ]
> 
> > +
> > +	wdog->timeout = clamp_t(unsigned, timeout, 1, IMX2_WDT_MAX_TIME);
> > +	if (wdog->timeout != timeout)
> >  		dev_warn(&pdev->dev, "Initial timeout out of range! "
> > -			"Clamped from %u to %u\n", timeout, imx2_wdt.timeout);
> > +			"Clamped from %u to %u\n", timeout, wdog->timeout);
> 
> Somewhat unrelated, but this results in a checkpatch warning.
> I would suggest to put the string in a single line.
> 
> 		dev_warn(&pdev->dev,
> 			 "Initial timeout out of range! Clamped from %u to %u\n",
> 			 timeout, wdog->timeout);

okay, I'll fix the warning.

Thanks,
Anatolij