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From: Guenter Roeck <linux@roeck-us.net>
To: Chris Packham <chris.packham@alliedtelesis.co.nz>,
	a.zummo@towertech.it, alexandre.belloni@bootlin.com
Cc: linux-rtc@vger.kernel.org, linux-watchdog@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] rtc: ds1307: provide an indication that the watchdog has fired
Date: Fri, 24 Jul 2020 07:32:43 -0700
Message-ID: <5d6aaac5-0ce2-cf54-61fa-cfbc3f6bc0b3@roeck-us.net> (raw)
In-Reply-To: <20200724045009.7293-1-chris.packham@alliedtelesis.co.nz>

On 7/23/20 9:50 PM, Chris Packham wrote:
> There's not much feedback when the ds1388 watchdog fires. Generally it
> yanks on the reset line and the board reboots. To provide some feedback
> indicate that the watchdog has fired in the past. This should help
> distinguish a watchdog triggered reset from a power interruption.
> 
> Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
> ---
>  drivers/rtc/rtc-ds1307.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/drivers/rtc/rtc-ds1307.c b/drivers/rtc/rtc-ds1307.c
> index 49702942bb08..431b1a50c483 100644
> --- a/drivers/rtc/rtc-ds1307.c
> +++ b/drivers/rtc/rtc-ds1307.c
> @@ -868,6 +868,14 @@ static int ds1388_wdt_start(struct watchdog_device *wdt_dev)
>  	struct ds1307 *ds1307 = watchdog_get_drvdata(wdt_dev);
>  	u8 regs[2];
>  	int ret;
> +	int val;
> +
> +	ret = regmap_read(ds1307->regmap, DS1388_REG_FLAG, &val);
> +	if (ret)
> +		return ret;
> +
> +	if (val & DS1388_BIT_WF)
> +		dev_notice(ds1307->dev, "detected watchdog alarm flag\n");
>  
>  	ret = regmap_update_bits(ds1307->regmap, DS1388_REG_FLAG,
>  				 DS1388_BIT_WF, 0);
> 

This should be reported with WDIOC_GETBOOTSTATUS / WDIOF_CARDRESET,
not as log message when starting the watchdog.

Guenter

      reply index

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-24  4:50 Chris Packham
2020-07-24 14:32 ` Guenter Roeck [this message]

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