[PATCH v2 2/2] watchdog: orion_wdt: stop the watchdog during system suspend

[Igor Velkov via B4 Relay]

From: Igor Velkov <iav at iav.lv>

The watchdog timer keeps counting across system suspend while the
userspace that pings it is frozen, so it expires and resets the system.
On a Kobol Helios4 (Armada 388) with a 60 s timeout the board resets
47-61 s into s2idle, whether the watchdog daemon or systemd's
RuntimeWatchdogSec holds the device.

Stop the timer on suspend and restart it on resume when it is active or
running in hardware, as sp805_wdt does. orion_wdt_start() reloads the
counter, so userspace gets a full timeout after resume.

Assisted-by: LLM
Signed-off-by: Igor Velkov <iav at iav.lv>
---
 drivers/watchdog/orion_wdt.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/drivers/watchdog/orion_wdt.c b/drivers/watchdog/orion_wdt.c
index ef64e3730001..c65042dc2329 100644
--- a/drivers/watchdog/orion_wdt.c
+++ b/drivers/watchdog/orion_wdt.c
@@ -671,6 +671,29 @@ static void orion_wdt_shutdown(struct platform_device *pdev)
 	orion_wdt_stop(wdt_dev);
 }
 
+static int orion_wdt_suspend(struct device *dev)
+{
+	struct watchdog_device *wdt_dev = dev_get_drvdata(dev);
+
+	if (watchdog_active(wdt_dev) || watchdog_hw_running(wdt_dev))
+		return orion_wdt_stop(wdt_dev);
+
+	return 0;
+}
+
+static int orion_wdt_resume(struct device *dev)
+{
+	struct watchdog_device *wdt_dev = dev_get_drvdata(dev);
+
+	if (watchdog_active(wdt_dev) || watchdog_hw_running(wdt_dev))
+		return orion_wdt_start(wdt_dev);
+
+	return 0;
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(orion_wdt_pm_ops, orion_wdt_suspend,
+				orion_wdt_resume);
+
 static struct platform_driver orion_wdt_driver = {
 	.probe		= orion_wdt_probe,
 	.remove		= orion_wdt_remove,
@@ -678,6 +701,7 @@ static struct platform_driver orion_wdt_driver = {
 	.driver		= {
 		.name	= "orion_wdt",
 		.of_match_table = orion_wdt_of_match_table,
+		.pm	= pm_sleep_ptr(&orion_wdt_pm_ops),
 	},
 };
 

-- 
2.43.0