On 09/22/2016 12:02 AM, Steffen Trumtrar wrote:
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.trumt...@pengutronix.de>
Cc: Wim Van Sebroeck <w...@iguana.be>
Cc: Guenter Roeck <li...@roeck-us.net>
Cc: linux-watch...@vger.kernel.org
---
 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 e024722e8b3b..5b067984d5e8 100644
--- a/drivers/watchdog/dw_wdt.c
+++ b/drivers/watchdog/dw_wdt.c
@@ -137,6 +137,21 @@ 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 (IS_ERR(dw_wdt->rst)) {
+               dev_warn(wdd->parent, "No reset line. Will not stop.\n");

As mentioned in the other patch, this warning is not warranted.

Also, you'll need to inform the watchdog core that the watchdog is still
running, otherwise the system _will_ reset. That would be a definite
and unwanted change in behavior.

+               return PTR_ERR(dw_wdt->rst);

This is not an error. The code handled that situation before without
reporting an error, it can handle it now.

+       }
+
+       reset_control_assert(dw_wdt->rst);
+       reset_control_deassert(dw_wdt->rst);
+
+       return 0;
+}
+
 static int dw_wdt_restart_handle(struct notifier_block *this,
                                 unsigned long mode, void *cmd)
 {
@@ -177,6 +192,7 @@ 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,


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