Re: [Patch v2 1/3] dt-bindings: rtc: pcf2127: Add bindings for nxp,pcf2127
From: Uwe Kleine-König
Date: Thu Sep 24 2020 - 03:05:16 EST
Hello,
On Thu, Sep 24, 2020 at 03:20:33AM +0000, Qiang Zhao wrote:
> On 21/09/2020 13:48:19+0800, Qiang Zhao wrote:
>
> > -----Original Message-----
> > From: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxx>
> > Sent: 2020年9月23日 17:45
> > To: Qiang Zhao <qiang.zhao@xxxxxxx>
> > Cc: Wim Van Sebroeck <wim@xxxxxxxxxxxxxxxxxx>; Guenter Roeck
> > <linux@xxxxxxxxxxxx>; linux-watchdog@xxxxxxxxxxxxxxx;
> > a.zummo@xxxxxxxxxxxx; robh+dt@xxxxxxxxxx; linux-rtc@xxxxxxxxxxxxxxx;
> > devicetree@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Uwe Kleine-König
> > <u.kleine-koenig@xxxxxxxxxxxxxx>
> > Subject: Re: [Patch v2 1/3] dt-bindings: rtc: pcf2127: Add bindings for
> > nxp,pcf2127
> >
> > Hi,
> >
> > You forgot to copy the watchdog maintainers, I think such a property should be
> > discussed with them.
> >
> > Note that I'm still convinced this is not a complete solution, see:
> > https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.kern
> > el.org%2Flinux-rtc%2F20200716181816.GF3428%40piout.net%2F&data=
> > 02%7C01%7Cqiang.zhao%40nxp.com%7Cb71f79a044b0493d6d4f08d85fa551c
> > b%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C1%7C637364510931174
> > 355&sdata=%2BOxrzB8RIuxM9Let5slhfCVmMm6PMNoERDeHC9%2Fdxng
> > %3D&reserved=0
haha
> Yes, you are right, There is not a fundamental solution.
> However it somewhat avoid this situation at least.
>
> And if without this issue,
> is it correct to register a rtc device as watchdog no matter it is used as watchdog on the board?
> Every time Linux are booted up, watchdog device should be configured to the right one manually.
> So the patch are useful, even though it is not for the issue.
>
> What should we do to really resolve this issue?
I still think we need a kernel solution here. I would expect that most
assembled pcf2127 chips are unable to act as a watchdog (i.e. don't have
the RST output connected to something that resets the machine).
So my favoured solution would be a positive property like:
has-watchdog;
or something similar. In my eyes this is definitely something we want to
specify in the device tree because it is a relevant hardware property.
I consider it a bug to give a watchdog device to userspace that isn't
functional.
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | https://www.pengutronix.de/ |
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