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From:   Geert Uytterhoeven <geert@linux-m68k.org>
Date:   Fri, 30 Oct 2020 10:14:03 +0100
Message-ID: <CAMuHMdXW6FVZ0xXm_d+u2FXKcnMx42tV=UYgWhYai3k-4O8VCg@mail.gmail.com>
Subject: Re: [PATCH 2/2] arm64: dts: renesas: r8a77961: ulcb-kf: Initial
 device tree
To:     Eugeniu Rosca <erosca@de.adit-jv.com>
Cc:     Linux-Renesas <linux-renesas-soc@vger.kernel.org>,
        Magnus Damm <magnus.damm@gmail.com>,
        Rob Herring <robh+dt@kernel.org>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Steffen Pengel <spengel@de.adit-jv.com>,
        Eugeniu Rosca <roscaeugeniu@gmail.com>
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Hi Eugeniu,

On Fri, Oct 30, 2020 at 10:07 AM Eugeniu Rosca <erosca@de.adit-jv.com> wrote:
> On Thu, Oct 29, 2020 at 07:23:53PM +0100, Geert Uytterhoeven wrote:
> > On Thu, Oct 29, 2020 at 5:34 PM Eugeniu Rosca <erosca@de.adit-jv.com> wrote:
>
> [..]
>
> > I don't think we want to add new compatible string to describe each
> > combo. Just add "renesas,r8a77961" to the last enum?
>
> I'm afraid I misinterpreted your request. I've pushed your proposal to
> https://lore.kernel.org/linux-renesas-soc/20201030083051.18752-4-erosca@de.adit-jv.com/

Thanks, got it!

> > > IMHO one thing which is certainly worth clarifying and fixing is the
> > > KF revision currently documented in renesas.yaml, i.e. M03.
> > >
> > > Shimafuji released at least M04, M05 and M06 revisions of KF (nicely
> > > compared at https://elinux.org/R-Car/Boards/Kingfisher#Change_point).
> > >
> > > The question is, does the community intend to support M03 through M06
> > > (in which case all of them might need an entry in the documentation) or
> > > anything which is earlier than M06 has to be considered deprecated (in
> > > which case renesas.yaml would need a simple s/M03/M06/ update)?
> >
> > I'm not that familiar with KingFisher and the various revisions.
> > Do these differences have an impact on the software side?
> > The diodes and filters probably don't.
>
> I personally no longer use KF M03, since its major limitation is not
> being able to update the contents of Hyperflash using Lauterbach if
> ULCB is stacked on the expansion board (unplugging ULCB each time
> it is flashed is absolutely not practical).

Note that if you build ATF with RCAR_RPC_HYPERFLASH_LOCKED=0,
you can access HF from U-Boot or Linux.

> I've heard from audio engineers that recent revisions are more suitable
> for audio use-cases, but I don't know the full details.
>
> > The I2C repeaters are PCA9548ADB on M03, hence they use a Linux
> > driver. By what have they been replaced?
> > What's the nature of the MOST ↔ GPS Function select register change?
>
> I will try to collect more information and, if I succeed, I will come
> back with feedback. Thank you for your patience.

Thanks!

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