[PATCH v1 1/2] dt-bindings: watchdog: Add NPCM reset status support

[Tomer Maimon]

On Mon, 16 Feb 2026 at 20:03, Krzysztof Kozlowski <krzk at kernel.org> wrote:

> On Mon, Feb 16, 2026 at 04:59:18PM +0200, Tomer Maimon wrote:
> > On Mon, 16 Feb 2026 at 16:48, Krzysztof Kozlowski <krzk at kernel.org>
> wrote:
> > > >>>>> +  syscon:
> > > >>>>
> > > >>>> First iteration. See "How to Get Your DT Schema Bindings Accepted
> in
> > > >>>> Less Than 10 Iterations"
> > > >>>>
> > > >>> Thanks, it was very helpful.
> > > >>> the syscon property is already found in the WD node
> > > >>> in nuvoton-common-npcm8xx.dtsi file, what should I do:
> > > >>
> > > >> How is that file related to this binding?
> > > >>
> > > >> Either you document existing ABI or you add new (for new device).
> Commit
> > > >> msg MUST be explicit about it and provide the reasons. If wrong
> (e.g.
> > > >> discouraged) ABI was already used then it depends how and when it
> got
> > > >> into the kernel, e.g. if someone bypassed DT completely just to get
> it
> > > >> inside.
> > > >>
> > > > The syscon property is already used in the upstream NPCM8xx DTSI
> watchdog
> > > > node, so I will document it as existing ABI and mark it deprecated. I
> > > will
> > >
> > > And how it is used? I cannot find its usage, so I do not agree on
> > > documenting it. Property should be removed or at least provide the
> > > justification/impact of removal, if you need it to stay.
> > >
> > > Understood. The syscon phandle is used by the watchdog driver to read
> and
>
> You messed up quotes.
>
> Can you point me to the line? I REALLY want to be sure that we are not
> wasting each other time, e.g. me looking at wrong code or you telling me
> some bollocks from downstream.
>
The syscon property is not used in the current upstream npcm_wdt driver.
It is used *in this patch set*, which introduces the function
npcm_get_reset_status(). Inside that function, the code calls:
gcr_regmap = syscon_regmap_lookup_by_phandle(dev->of_node, "syscon");
to obtain the GCR regmap, read the reset‑status registers, clear them, and
report the reset cause via the watchdog bootstatus.
This usage is shown here:
https://www.spinics.net/lists/kernel/msg6045622.html
In addition, the watchdog maintainer confirmed that the reset cause can be
exposed without the deprecated reset‑type DT properties:
https://www.spinics.net/lists/kernel/msg6052106.html

Given this, should I remove the unused syscon phandle from the NPCM8xx DTSI
first, since no upstream driver currently uses it and it is therefore not
part of the ABI?
In this patch set, I am adding the first upstream usage of the GCR regmap
in the watchdog driver, so I plan to introduce the new, preferred
nuvoton,sysgcr property in the binding and use it in the DTSI, without
keeping the old syscon name unless you think backward compatibility is
needed.

Please let me know if you prefer that I update the DTSI first or include
the DTSI and binding changes in the same series.

>
> > clear the GCR reset‑status registers and then report the reset cause
> > through the watchdog bootstatus bits.
> > Therefore, this property should appear in the binding only because the
> > watchdog driver actually uses it — which I am implementing in this patch
> > set.
> > I will document it accordingly, and also add the new nuvoton,sysgcr
> phandle
> > as the preferred name.
>
> Best regards,
> Krzysztof
>
>
Best regards,

Tomer
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.ozlabs.org/pipermail/openbmc/attachments/20260217/5b8813d0/attachment.htm>