linux-kernel - [PATCH v2 1/2] watchdog: dw_wdt: add stop watchdog operation

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Message-Id: <20170914113013.19157-1-o.rempel@pengutronix.de>
Date:   Thu, 14 Sep 2017 13:30:12 +0200
From:   Oleksij Rempel <o.rempel@...gutronix.de>
To:     Wim Van Sebroeck <wim@...ana.be>,
        Guenter Roeck <linux@...ck-us.net>,
        Dinh Nguyen <dinguyen@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>
Cc:     Steffen Trumtrar <s.trumtrar@...gutronix.de>,
        Oleksij Rempel <o.rempel@...gutronix.de>,
        linux-watchdog@...r.kernel.org, kernel@...gutronix.de,
        Russell King <linux@...linux.org.uk>,
        devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH v2 1/2] watchdog: dw_wdt: add stop watchdog operation

From: Steffen Trumtrar <s.trumtrar@...gutronix.de>

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.

Signed-off-by: Steffen Trumtrar <s.trumtrar@...gutronix.de>
Signed-off-by: Oleksij Rempel <o.rempel@...gutronix.de>
Cc: Wim Van Sebroeck <wim@...ana.be>
Cc: Guenter Roeck <linux@...ck-us.net>
Cc: linux-watchdog@...r.kernel.org
---

changes v2:
 - test if dw_wdt->rst is NULL instead of IS_ERR

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

diff --git a/drivers/watchdog/dw_wdt.c b/drivers/watchdog/dw_wdt.c
index 36be987ff9ef..a507f36302e1 100644
--- a/drivers/watchdog/dw_wdt.c
+++ b/drivers/watchdog/dw_wdt.c
@@ -135,6 +135,21 @@ static int dw_wdt_start(struct watchdog_device *wdd)
 	return 0;
 }
 
+static int dw_wdt_stop(struct watchdog_device *wdd)
+{
+	struct dw_wdt *dw_wdt = to_dw_wdt(wdd);
+
+	if (!dw_wdt->rst) {
+		dev_warn(wdd->parent, "No reset line. Will not stop.\n");
+		return -EOPNOTSUPP;
+	}
+
+	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 +188,7 @@ static const struct watchdog_info dw_wdt_ident = {
 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,
-- 
2.11.0