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SubjectRe: [PATCH v1 1/2] watchdog: dw_wdt: add stop watchdog operation
On Thu, Sep 14, 2017 at 10:14:01AM +0200, Oleksij Rempel wrote:
> From: Steffen Trumtrar <s.trumtrar@pengutronix.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@pengutronix.de>
> Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
> Cc: Wim Van Sebroeck <wim@iguana.be>
> Cc: Guenter Roeck <linux@roeck-us.net>
> Cc: linux-watchdog@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 36be987ff9ef..50d8a6a5b5ac 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 (IS_ERR(dw_wdt->rst)) {
> + dev_warn(wdd->parent, "No reset line. Will not stop.\n");
> + return PTR_ERR(dw_wdt->rst);
> + }

This is a change in behavior. Previously, with no stop function,
the watchdog core would keep pinging the watchdog in this situation.
Now it would end up spitting a warning and resetting the system.

> +
> + 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
>

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