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From:   Geert Uytterhoeven <geert@linux-m68k.org>
Date:   Wed, 9 Jun 2021 17:57:43 +0200
Message-ID: <CAMuHMdXQkqyQtXEPWTuAF9LG0HFPEJEWLuME_X0ejrs0G4J4Uw@mail.gmail.com>
Subject: Re: [PATCH 2/3] soc: renesas: Add support to read LSI DEVID register
 of RZ/G2{L,LC} SoC's
To:     "Lad, Prabhakar" <prabhakar.csengg@gmail.com>
Cc:     Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>,
        Magnus Damm <magnus.damm@gmail.com>,
        Rob Herring <robh+dt@kernel.org>,
        Linux-Renesas <linux-renesas-soc@vger.kernel.org>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Biju Das <biju.das.jz@bp.renesas.com>
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Hi Prabhakar,

On Wed, Jun 9, 2021 at 5:50 PM Lad, Prabhakar
<prabhakar.csengg@gmail.com> wrote:
> On Wed, Jun 9, 2021 at 8:27 AM Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> > On Fri, Jun 4, 2021 at 8:09 PM Lad Prabhakar
> > <prabhakar.mahadev-lad.rj@bp.renesas.com> wrote:
> > > Add support for reading the LSI DEVID register which is present in
> > > SYSC block of RZ/G2{L,LC} SoC's.
> > >
> > > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> > > Reviewed-by: Biju Das <biju.das.jz@bp.renesas.com>
> >
> > Thanks for your patch!
> >
> > > --- a/drivers/soc/renesas/renesas-soc.c
> > > +++ b/drivers/soc/renesas/renesas-soc.c
> > > @@ -56,6 +56,11 @@ static const struct renesas_family fam_rzg2 __initconst __maybe_unused = {
> > >         .reg    = 0xfff00044,           /* PRR (Product Register) */
> > >  };
> > >
> > > +static const struct renesas_family fam_rzg2l __initconst __maybe_unused = {
> > > +       .name   = "RZ/G2L",
> > > +       .reg    = 0x11020a04,
> >
> > Please don't add hardcoded register addresses for new SoCs (i.e. drop
> > ".reg").  The "renesas,r9a07g044-sysc" is always present.
> > And if it were missing, the hardcoded fallback would lead into the
> > classic CCCR/PRR scheme, which is not correct for RZ/G2L...
> >
> I wanted to avoid iomap for the entire sysc block for just a single register.

The mapping will be rounded up to PAGE_SIZE anyway
(I know, SYSC is 64 KiB, hence larger than the typical page size).

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

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