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From:   Arnd Bergmann <arnd@arndb.de>
Date:   Fri, 30 Jul 2021 18:55:02 +0200
Message-ID: <CAK8P3a1c9bVjACjAN=2d+XiBn+yWgHHs9CEUmik7U61+3MzFhw@mail.gmail.com>
Subject: Re: [PATCH 4/5] ARM: Add basic support for EcoNet EN7523 SoC
To:     John Crispin <john@phrozen.org>
Cc:     Arnd Bergmann <arnd@arndb.de>, Bert Vermeulen <bert@biot.com>,
        DTML <devicetree@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        Russell King <linux@armlinux.org.uk>,
        Linus Walleij <linus.walleij@linaro.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Geert Uytterhoeven <geert+renesas@glider.be>,
        Anshuman Khandual <anshuman.khandual@arm.com>,
        Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>,
        Ard Biesheuvel <ardb@kernel.org>,
        YiFei Zhu <yifeifz2@illinois.edu>,
        Mike Rapoport <rppt@kernel.org>,
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        <u.kleine-koenig@pengutronix.de>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Kees Cook <keescook@chromium.org>,
        Masahiro Yamada <masahiroy@kernel.org>,
        Nathan Chancellor <nathan@kernel.org>,
        Viresh Kumar <viresh.kumar@linaro.org>,
        Felix Fietkau <nbd@nbd.name>,
        Matthias Brugger <matthias.bgg@gmail.com>
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On Fri, Jul 30, 2021 at 5:16 PM John Crispin <john@phrozen.org> wrote:
> On 30.07.21 16:48, Arnd Bergmann wrote:
> > Given how closely related this probably is to MT7623/MT7622, should this
> > perhaps just be part of arch/arm/mach-mediatek? According to
> > https://wikidevi.wi-cat.ru/MediaTek#xPON, the older (mips based) MT752x
> > chips are apparently just rebranded to EN752x after the business unit
> > was spun off, but I guess they are still in the same family.
>
> Hi,
>
> ECNT (what was once known as trendchip) is now a subsidary of MTK (and
> not a BU if I am understanding it correctly).
>
> the EN7523 is rather similar to the MT7622 for some parts, other parts
> (spi, flash, wdt, gpio, .. drivers all needed to be rewritten and will
> be part of the next series).
>
> the older MIPS silicon shares almost no IP with the current ARM silicon.

Ah, so I guess the old Trendchip parts were separately developed separately
from the Ralink parts before the original acquisition, and then Ralink/Mediatek
combined the two product lines before spinning off the dsl products into
a new subsidiary.

> not really my call to decide which folder this should live in. it seemed
> natural to just give it its own folder, as ECNT is not a BU of MTK.
>
> we can change that however if required.

My preference would be to have a common directory for both,
but I'm not going to require that. From the kernel perspective the
main question is actually not who makes the parts but who is going
to maintain the code.

Matthias is doing a good job taking care of the Mediatek parts,
and he's familiar with the arm-soc process. If there is enough overlap
between the Mediatek and EcoNet devices that we would expect
either conflicts between binding/driver patches, or that you would want
each other to review the patches for related parts, then it would
make most sense to have a common directory and maintainer
entry for both, with all patches going through the same git tree.

It would also be nice to have someone listed as second maintainer
for mediatek, since Matthias is currently the only one listed there.
(Doesn't have to be you, I don't mean to drag you into taking up
more work if you don't want to).

Please discuss this between the three of you (Bert, John and
Matthias), and let me know what you think works best for all of
you.

       Arnd