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From:   Geert Uytterhoeven <geert@linux-m68k.org>
Date:   Mon, 6 Dec 2021 13:16:40 +0100
Message-ID: <CAMuHMdXxO-CP0Ao8q8r4Gw5e5FzCznhSxt2JWz13zbnt2tnzVQ@mail.gmail.com>
Subject: Re: [PATCH v1 3/3] mmc: Add driver for LiteX's LiteSDCard interface
To:     Joel Stanley <joel@jms.id.au>
Cc:     Gabriel Somlo <gsomlo@gmail.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        devicetree <devicetree@vger.kernel.org>,
        Ulf Hansson <ulf.hansson@linaro.org>,
        linux-mmc <linux-mmc@vger.kernel.org>,
        Karol Gugala <kgugala@antmicro.com>,
        Mateusz Holenko <mholenko@antmicro.com>,
        Kamil Rakoczy <krakoczy@antmicro.com>,
        mdudek@internships.antmicro.com,
        Paul Mackerras <paulus@ozlabs.org>,
        Stafford Horne <shorne@gmail.com>,
        david.abdurachmanov@sifive.com,
        Florent Kermarrec <florent@enjoy-digital.fr>
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Hi Joel,

On Mon, Dec 6, 2021 at 11:53 AM Joel Stanley <joel@jms.id.au> wrote:
>  On Fri, 3 Dec 2021 at 23:42, Gabriel Somlo <gsomlo@gmail.com> wrote:
> > LiteX (https://github.com/enjoy-digital/litex) is a SoC framework
> > that targets FPGAs. LiteSDCard is a small footprint, configurable
> > SDCard core commonly used in LiteX designs.
> >
> > The driver was first written in May 2020 and has been maintained
> > cooperatively by the LiteX community. Thanks to all contributors!
> >
> > Co-developed-by: Kamil Rakoczy <krakoczy@antmicro.com>
> > Signed-off-by: Kamil Rakoczy <krakoczy@antmicro.com>
> > Co-developed-by: Maciej Dudek <mdudek@internships.antmicro.com>
> > Signed-off-by: Maciej Dudek <mdudek@internships.antmicro.com>
> > Co-developed-by: Paul Mackerras <paulus@ozlabs.org>
> > Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
> > Signed-off-by: Gabriel Somlo <gsomlo@gmail.com>

> > --- a/drivers/mmc/host/Kconfig
> > +++ b/drivers/mmc/host/Kconfig

> Did you test using this as a module?
>
> > +       depends on OF && LITEX
>
> I don't like having litex drivers depend on the LITEX kconfig. The
> symbol is not user visible, and to enable it we need to build in the
> litex controller driver, which platforms may or may not have.
>
> The microwatt platform is an example of a SoC that embeds some LITEX
> IP, but may or may not be a litex SoC.

I do like the LITEX dependency, as it allows us to gate off a bunch of
related drivers, and avoid annoying users with questions about them,
using a single symbol.

Originally, people told me the system controller is always present,
hence the current logic to have LITEX_SOC_CONTROLLER visible, and
an invisible LITEX (which is shorter to type) for individual drivers
to depend on.

Perhaps the logic should be reworked, now the old assumptions are no
longer true?

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