Re: [PATCH] watchdog: max77620: Add support for watchdog timer

[Guenter Roeck]

On 06/08/2016 01:58 AM, Laxman Dewangan wrote:
> Hi Guenter,
>
> Thanks for quick review. I will take care of most of comment.
> I have one query fr following comment.
>
> Thanks,
> Laxman
>
> On Tuesday 07 June 2016 11:26 PM, Guenter Roeck wrote:
> > Hi,
> >
> > On Mon, Jun 06, 2016 at 05:22:44PM +0530, Laxman Dewangan wrote:
> > +    /* Stop watchodog */
> > +    ret = regmap_update_bits(wdt->rmap, MAX77620_REG_CNFGGLBL2,
> > +                 MAX77620_WDTEN, 0);
> > +    if (ret < 0) {
> > +        dev_err(wdt->dev, "Failed to reset WDTEN: %d\n", ret);
> > +        return ret;
> > +    }
> > Alternatively, you could set WDOG_HW_RUNNING to tell the watchdog core
> > that the watchdog is already running. The watchdog core would then ping
> > the watchdog until the watchdog device is opened.
> >
> > That would also require to tell the watchdog core about the current (or default)
> > timeout, which doesn't seem to be set anywhere. That means it won't be set at all
> > unless user space updates it explicitly. This is quite unusual. Is it on purpose
> > or an oversight ? If it is on purpose, please explain.
>
> OK, we have use cases where we have enabled the WDT in BL also. and keep runnign till kernel up.
> Instead of stopping WDT, I can say that WDOG_HW_RUNING and current timeout can be read from the register.
>
> Now, the WDT need to be ping periodically. Is there any flag which enabled the worker thread from core which will keep pinging till user space alive and activate the WDT?
The watchdog core will start the worker if WDOG_HW_RUNNING is set.

Guenter