Patch "watchdog: dw_wdt: add stop watchdog operation" has been added to the 4.15-stable tree

This is a note to let you know that I've just added the patch titled

watchdog: dw_wdt: add stop watchdog operation

to the 4.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
watchdog-dw_wdt-add-stop-watchdog-operation.patch
and it can be found in the queue-4.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Oleksij Rempel <[email protected]>
Date: Tue, 26 Sep 2017 08:11:22 +0200
Subject: watchdog: dw_wdt: add stop watchdog operation

From: Oleksij Rempel <[email protected]>

[ Upstream commit 1bfe8889380890efe4943d125124f5a7b48571b0 ]

The only way of stopping the watchdog is by resetting it. Add the watchdog op for stopping the device and reset if a reset line is provided.

At same time WDOG_HW_RUNNING should be remove from dw_wdt_start. As commented by Guenter Roeck:
dw_wdt sets WDOG_HW_RUNNING in its open function. Result is that the kref_get() in watchdog_open() won't be executed. But then kref_put() in close will be called since the watchdog now does stop. This causes the imbalance.

---
 drivers/watchdog/dw_wdt.c |   18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

@@ -127,14 +127,27 @@ static int dw_wdt_start(struct watchdog_
 
 	dw_wdt_set_timeout(wdd, wdd->timeout);
 
-	set_bit(WDOG_HW_RUNNING, &wdd->status);
-
 	writel(WDOG_CONTROL_REG_WDT_EN_MASK,
 	       dw_wdt->regs + WDOG_CONTROL_REG_OFFSET);
 
 	return 0;
 }
 
+static int dw_wdt_stop(struct watchdog_device *wdd)
+{
+	struct dw_wdt *dw_wdt = to_dw_wdt(wdd);
+
+	if (!dw_wdt->rst) {
+		set_bit(WDOG_HW_RUNNING, &wdd->status);
+		return 0;
+	}
+
+	reset_control_assert(dw_wdt->rst);
+	reset_control_deassert(dw_wdt->rst);
+
+	return 0;
+}
+
 static int dw_wdt_restart(struct watchdog_device *wdd,
 			  unsigned long action, void *data)
 {

@@ -173,6 +186,7 @@ static const struct watchdog_info dw_wdt
 static const struct watchdog_ops dw_wdt_ops = {
 	.owner		= THIS_MODULE,
 	.start		= dw_wdt_start,
+	.stop		= dw_wdt_stop,
 	.ping		= dw_wdt_ping,
 	.set_timeout	= dw_wdt_set_timeout,
 	.get_timeleft	= dw_wdt_get_timeleft,

Patches currently in stable-queue which might be from [email protected] are

queue-4.15/watchdog-dw_wdt-add-stop-watchdog-operation.patch