Re: [PATCH v2 1/3] dt-bindings: arm: renesas: Document Renesas RZ/V2M System Configuration

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Hi Biju,

On Mon, Nov 14, 2022 at 8:22 PM Biju Das <biju.das.jz@xxxxxxxxxxxxxx> wrote:
> > Subject: Re: [PATCH v2 1/3] dt-bindings: arm: renesas: Document Renesas
> > RZ/V2M System Configuration
> > On Mon, Nov 14, 2022 at 6:05 PM Biju Das <biju.das.jz@xxxxxxxxxxxxxx> wrote:
> > > > From: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx> On
> > > > 14/11/2022 17:44, Biju Das wrote:
> > > > >>>>> If the hardware manual said this is called "foo-whatever-name"
> > > > >>>>> or "rz85736dfnx2", you would use it as well?
> > > > >>>>>
> > > > >>>>> Node names should be generic.
> > > > >>>
> > > > >>> I got the following feedback from LSI team.
> > > > >>>
> > > > >>> *The reason why we use "configuration" and not "controller" is
> > > > >>> the possibility that users might take it to mean "control" of
> > > > >>> system operation (product operation). This unit determines how
> > > > >>> the whole LSI
> > > > >> configure to operate LSI, so we use "configuration" for this IP name.
> > > > >>>
> > > > >>> As per this it is not a controller. It is a Configuration IP.
> > > > >>>
> > > > >>> What should be generic node name for system configuration IP?
> > > > >>
> > > > >> Then it's closer to chipid and should be in hwinfo?
> > > > >
> > > > > You mean, sys: hwinfo@a3f03000 instead of sys: system-
> > > > configuration@a3f03000 ??
> > > >
> > > > Rather be put in hwinfo directory. Typical name is "chipid", but I
> > > > don't know if your device is a chipid.
> > >
> > > This IP is for sure not a chipid. We can detect SoC version. That is
> > > one of the functions provided by this IP.
> > >
> > > > > Also the same IP block is present on rz/v2ma as well?
> > > > >
> > > > > Shall I use the same file renesas,rzv2m-sys.yaml for both
> > > > > r9a09g011-sys and
> > > > r9a09g055-sys?
> >
> > Are they sufficiently similar? E.g. we have renesas,rst.yaml for the various
> > R-Car reset controllers, which have different register layouts.
>
> I have been told both RZ/V2M and RZ/V2MA are exactly same, but later does not have ISP module.

OK...

> > If the SoC version register is located at the same offset, it might be
> > worthwhile to add a family-specific compatible value, too, so the soc_device
> > driver doesn't have to contain a big list to match against.
>
> The SoC version registers are located at the same offset.
> But there is no way to distinguish both the SoCs.

So they really are the same SoC, with the ISP disabled (by fuses?).

Then I guess the most sensible thing to do is to just use

    compatible = "renesas,r9a09g055", "renesas,r9a09g011"

at the top level, and keep all other compatible values unchanged?
Cfr. what we did for R-Car Gen3e (r8a779mX).

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds



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