watchdog: imx2: Convert to use infrastructure triggered keepalives

The watchdog infrastructure now supports handling watchdog keepalive
if the watchdog is running while the watchdog device is closed.
Convert the driver to use this infrastructure.
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

drivers/watchdog/imx2_wdt.c

@@ -25,14 +25,12 @@
 #include <linux/delay.h>
 #include <linux/init.h>
 #include <linux/io.h>
-#include <linux/jiffies.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/of_address.h>
 #include <linux/platform_device.h>
 #include <linux/regmap.h>
-#include <linux/timer.h>
 #include <linux/watchdog.h>
 
 #define DRIVER_NAME "imx2-wdt"
@@ -60,7 +58,6 @@
 struct imx2_wdt_device {
 	struct clk *clk;
 	struct regmap *regmap;
-	struct timer_list timer;	/* Pings the watchdog when closed */
 	struct watchdog_device wdog;
 };
 
@@ -147,16 +144,6 @@ static int imx2_wdt_ping(struct watchdog_device *wdog)
 	return 0;
 }
 
-static void imx2_wdt_timer_ping(unsigned long arg)
-{
-	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 int imx2_wdt_set_timeout(struct watchdog_device *wdog,
 				unsigned int new_timeout)
 {
@@ -173,40 +160,19 @@ static int imx2_wdt_start(struct watchdog_device *wdog)
 {
 	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
 
-	if (imx2_wdt_is_running(wdev)) {
-		/* delete the timer that pings the watchdog after close */
-		del_timer_sync(&wdev->timer);
+	if (imx2_wdt_is_running(wdev))
 		imx2_wdt_set_timeout(wdog, wdog->timeout);
-	} else
+	else
 		imx2_wdt_setup(wdog);
 
-	return imx2_wdt_ping(wdog);
-}
-
-static int imx2_wdt_stop(struct watchdog_device *wdog)
-{
-	/*
-	 * 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 inline void imx2_wdt_ping_if_active(struct watchdog_device *wdog)
-{
-	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
+	set_bit(WDOG_HW_RUNNING, &wdog->status);
 
-	if (imx2_wdt_is_running(wdev)) {
-		imx2_wdt_set_timeout(wdog, wdog->timeout);
-		imx2_wdt_timer_ping((unsigned long)wdog);
-	}
+	return imx2_wdt_ping(wdog);
 }
 
 static const struct watchdog_ops imx2_wdt_ops = {
 	.owner = THIS_MODULE,
 	.start = imx2_wdt_start,
-	.stop = imx2_wdt_stop,
 	.ping = imx2_wdt_ping,
 	.set_timeout = imx2_wdt_set_timeout,
 	.restart = imx2_wdt_restart,
@@ -254,7 +220,7 @@ static int __init imx2_wdt_probe(struct platform_device *pdev)
 	wdog->info		= &imx2_wdt_info;
 	wdog->ops		= &imx2_wdt_ops;
 	wdog->min_timeout	= 1;
-	wdog->max_timeout	= IMX2_WDT_MAX_TIME;
+	wdog->max_hw_heartbeat_ms = IMX2_WDT_MAX_TIME * 1000;
 	wdog->parent		= &pdev->dev;
 
 	ret = clk_prepare_enable(wdev->clk);
@@ -275,9 +241,10 @@ static int __init imx2_wdt_probe(struct platform_device *pdev)
 	watchdog_set_restart_priority(wdog, 128);
 	watchdog_init_timeout(wdog, timeout, &pdev->dev);
 
-	setup_timer(&wdev->timer, imx2_wdt_timer_ping, (unsigned long)wdog);
-
-	imx2_wdt_ping_if_active(wdog);
+	if (imx2_wdt_is_running(wdev)) {
+		imx2_wdt_set_timeout(wdog, wdog->timeout);
+		set_bit(WDOG_HW_RUNNING, &wdog->status);
+	}
 
 	/*
 	 * Disable the watchdog power down counter at boot. Otherwise the power
@@ -310,7 +277,6 @@ static int __exit imx2_wdt_remove(struct platform_device *pdev)
 	watchdog_unregister_device(wdog);
 
 	if (imx2_wdt_is_running(wdev)) {
-		del_timer_sync(&wdev->timer);
 		imx2_wdt_ping(wdog);
 		dev_crit(&pdev->dev, "Device removed: Expect reboot!\n");
 	}
@@ -324,10 +290,9 @@ static void imx2_wdt_shutdown(struct platform_device *pdev)
 
 	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
+		 * We are running, configure 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");
@@ -345,10 +310,6 @@ static int imx2_wdt_suspend(struct device *dev)
 	if (imx2_wdt_is_running(wdev)) {
 		imx2_wdt_set_timeout(wdog, IMX2_WDT_MAX_TIME);
 		imx2_wdt_ping(wdog);
-
-		/* The watchdog is not active */
-		if (!watchdog_active(wdog))
-			del_timer_sync(&wdev->timer);
 	}
 
 	clk_disable_unprepare(wdev->clk);
@@ -374,19 +335,10 @@ static int imx2_wdt_resume(struct device *dev)
 		 * watchdog again.
 		 */
 		imx2_wdt_setup(wdog);
+	}
+	if (imx2_wdt_is_running(wdev)) {
 		imx2_wdt_set_timeout(wdog, wdog->timeout);
 		imx2_wdt_ping(wdog);
-	} else if (imx2_wdt_is_running(wdev)) {
-		/* Resuming from non-deep sleep state. */
-		imx2_wdt_set_timeout(wdog, wdog->timeout);
-		imx2_wdt_ping(wdog);
-		/*
-		 * But the watchdog is not active, then start
-		 * the timer again.
-		 */
-		if (!watchdog_active(wdog))
-			mod_timer(&wdev->timer,
-				  jiffies + wdog->timeout * HZ / 2);
 	}
 
 	return 0;