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Message-ID: <20200125231126.GA25513@roeck-us.net>
Date: Sat, 25 Jan 2020 15:11:26 -0800
From: Guenter Roeck <linux@...ck-us.net>
To: Marco Felsch <m.felsch@...gutronix.de>
Cc: support.opensource@...semi.com, stwiss.opensource@...semi.com,
Adam.Thomson.Opensource@...semi.com,
linux-watchdog@...r.kernel.org, linux-kernel@...r.kernel.org,
kernel@...gutronix.de
Subject: Re: [PATCH] watchdog: da9062: do not ping the hw during stop()
On Mon, Jan 20, 2020 at 10:17:29AM +0100, Marco Felsch wrote:
> The da9062 hw has a minimum ping cool down phase of at least 200ms. The
> driver takes that into account by setting the min_hw_heartbeat_ms to
> 300ms and the core guarantees that the hw limit is observed for the
> ping() calls. But the core can't guarantees the required minimum ping
guarantee
> cool down phase if a stop() command is send immediately after the ping()
> command. So it is not allowed to ping the watchdog within the stop()
> command as the driver do. Remove the ping can be done without doubts
does
> because the watchdog gets disabled anyway and a (re)start reset the
resets
> watchdog counter too.
>
> Signed-off-by: Marco Felsch <m.felsch@...gutronix.de>
Reviewed-by: Guenter Roeck <linux@...ck-us.net>
> ---
> drivers/watchdog/da9062_wdt.c | 7 -------
> 1 file changed, 7 deletions(-)
>
> diff --git a/drivers/watchdog/da9062_wdt.c b/drivers/watchdog/da9062_wdt.c
> index 77b6b5336067..0ad15d55071c 100644
> --- a/drivers/watchdog/da9062_wdt.c
> +++ b/drivers/watchdog/da9062_wdt.c
> @@ -97,13 +97,6 @@ static int da9062_wdt_stop(struct watchdog_device *wdd)
> struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
> int ret;
>
> - ret = da9062_reset_watchdog_timer(wdt);
> - if (ret) {
> - dev_err(wdt->hw->dev, "Failed to ping the watchdog (err = %d)\n",
> - ret);
> - return ret;
> - }
> -
> ret = regmap_update_bits(wdt->hw->regmap,
> DA9062AA_CONTROL_D,
> DA9062AA_TWDSCALE_MASK,
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