Re: [PATCH RFC v2 5/9] dt-bindings: watchdog: renesas,r9a09g057-wdt: Add SYS syscon support

[Lad, Prabhakar]

Hi Geert,

Thank you for the review.

On Mon, Jul 13, 2026 at 4:55 PM Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> wrote:
>
> Hi Prabhakar,
>
> On Thu, 2 Jul 2026 at 14:31, Prabhakar <prabhakar.csengg@xxxxxxxxx> wrote:
> > From: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>
> >
> > On the Renesas RZ/T2H SoC, the Watchdog Timer Control Register (WDTDCR)
> > resides within the System Controller (SYS) block rather than the WDT
> > address space itself.
> >
> > Previously, this was handled by including a second register range in the
> > "reg" property. However, this is architecturally incorrect as the SYS
> > block consists of two distinct regions (0x80290000 and 0x81290000) that
> > contain registers for multiple peripheral blocks.
> >
> > Now that the SYS driver provides a unified syscon regmap, introduce the
> > "renesas,sys" phandle-array property to allow the WDT driver to
> > access its control register via the system controller.
> >
> > Mark the use of a second "reg" entry as deprecated in favor of the
> > new phandle-array approach for SoCs that require WDTDCR access.
> >
> > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>
> > ---
> > v1->v2:
> > - No change.
>
> Thanks for the update!
>
> > --- a/Documentation/devicetree/bindings/watchdog/renesas,r9a09g057-wdt.yaml
> > +++ b/Documentation/devicetree/bindings/watchdog/renesas,r9a09g057-wdt.yaml
> > @@ -48,6 +48,17 @@ properties:
> >    resets:
> >      maxItems: 1
> >
> > +  renesas,sys:
>
> In Documentation/devicetree/bindings/pci/renesas,r9a08g045-pcie.yaml,
> the similar property is called "renesas,sysc".
>
Ok, I will rename this to "renesas,sysc".

> > +    description:
> > +      System controller registers control the start/stop of the WDT, and halt debug.
> > +    $ref: /schemas/types.yaml#/definitions/phandle-array
> > +    items:
> > +      - items:
> > +          - description: phandle to system controller
> > +          - description: watchdog IP instance index
> > +            minimum: 0
> > +            maximum: 5
> > +
> >    timeout-sec: true
> >
> >  required:
> > @@ -73,15 +84,29 @@ allOf:
> >            minItems: 2
> >          clock-names:
> >            minItems: 2
> > +        renesas,sys: false
> >      else:
> >        properties:
> >          clocks:
> >            maxItems: 1
> >          clock-names:
> >            maxItems: 1
> > -        reg:
> > -          minItems: 2
> >          resets: false
> > +      allOf:
> > +        - if:
> > +            required:
> > +              - renesas,sys
> > +          then:
> > +            properties:
> > +              reg:
> > +                maxItems: 1
> > +          else:
> > +            properties:
> > +              reg:
> > +                description: Deprecated. Use renesas,sys to pass the offset
> > +                             of WDTDCR register instead.
>
> the index of the watchdog IP instance?
>
I will update the description to "Deprecated. Use the renesas,sysc
property along with the watchdog IP instance index instead."

Cheers,
Prabhakar