[PATCH v2 5/9] watchdog: msc313e: Fix spurious reset on suspend

[Tzung-Bi Shih]

If the hardware watchdog was started by the bootloader and the device is
suspended before userspace opens it, the ping worker (from watchdog
core) is frozen and the active hardware timer continues running.  This
leads to a spurious system reset.

Check both watchdog_active() and watchdog_hw_running() when deciding
whether to start or stop the watchdog during suspend and resume.

Additionally, call watchdog_stop_ping_on_suspend() to ensure the ping
worker be correctly paused and restarted during suspend and resume.

Fixes: ffd264bd152c ("watchdog: msc313e: Check if the WDT was running at boot")
Signed-off-by: Tzung-Bi Shih <tzungbi@xxxxxxxxxx>
---
v2:
- New to the series.
---
 drivers/watchdog/msc313e_wdt.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/watchdog/msc313e_wdt.c b/drivers/watchdog/msc313e_wdt.c
index 7c4593566781..c7d558fefc86 100644
--- a/drivers/watchdog/msc313e_wdt.c
+++ b/drivers/watchdog/msc313e_wdt.c
@@ -156,6 +156,7 @@ static int msc313e_wdt_probe(struct platform_device *pdev)
 	watchdog_init_timeout(&priv->wdev, timeout, dev);
 	watchdog_stop_on_reboot(&priv->wdev);
 	watchdog_stop_on_unregister(&priv->wdev);
+	watchdog_stop_ping_on_suspend(&priv->wdev);
 
 	ret = devm_watchdog_register_device(dev, &priv->wdev);
 
@@ -170,7 +171,7 @@ static int __maybe_unused msc313e_wdt_suspend(struct device *dev)
 {
 	struct msc313e_wdt_priv *priv = dev_get_drvdata(dev);
 
-	if (watchdog_active(&priv->wdev))
+	if (watchdog_active(&priv->wdev) || watchdog_hw_running(&priv->wdev))
 		msc313e_wdt_stop(&priv->wdev);
 
 	return 0;
@@ -180,7 +181,7 @@ static int __maybe_unused msc313e_wdt_resume(struct device *dev)
 {
 	struct msc313e_wdt_priv *priv = dev_get_drvdata(dev);
 
-	if (watchdog_active(&priv->wdev))
+	if (watchdog_active(&priv->wdev) || watchdog_hw_running(&priv->wdev))
 		msc313e_wdt_start(&priv->wdev);
 
 	return 0;
-- 
2.53.0