Re: [PATCH v2] arm64: dts: allwinner: a64: Enable eMMC on A64-OLinuXino

[Chen-Yu Tsai <wens@csie.org>]

On Wed, Aug 7, 2019 at 10:45 PM Maxime Ripard <maxime.ripard@bootlin.com> wrote:
>
> Hi,
>
> On Wed, Aug 07, 2019 at 08:09:19PM +0800, Chen-Yu Tsai wrote:
> > On Wed, Aug 7, 2019 at 8:01 PM Maxime Ripard <maxime.ripard@bootlin.com> wrote:
> > >
> > > On Tue, Aug 06, 2019 at 02:25:17PM +0800, Chen-Yu Tsai wrote:
> > > > On Mon, Aug 5, 2019 at 8:58 PM Martin Ayotte <martinayotte@gmail.com> wrote:
> > > > >
> > > > > Fine for me too.
> > > > >
> > > > > Thanks .
> > > > >
> > > > > -----Message d'origine-----
> > > > > De : Sunil Mohan Adapa [mailto:sunil@medhas.org]
> > > > > Envoyé : Monday, August 05, 2019 1:25 AM
> > > > > Ą : Chen-Yu Tsai
> > > > > Cc : Maxime Ripard; Martin Ayotte; linux-arm-kernel
> > > > > Objet : Re: [PATCH v2] arm64: dts: allwinner: a64: Enable eMMC on
> > > > > A64-OLinuXino
> > > > >
> > > > > On 04/08/19 8:33 pm, Chen-Yu Tsai wrote:
> > > > > > On Fri, Aug 2, 2019 at 2:47 AM Sunil Mohan Adapa <sunil@medhas.org> wrote:
> > > > > >>
> > > > > >> On 01/08/19 6:49 am, Martin Ayotte wrote:
> > > > > >>> If my SOB could help here, I don't mind since I've done the commit
> > > > > >>> more than a year ago for Armbian ...
> > > > > >>>
> > > > > >>> Signed-off-by: Martin Ayotte <martinayotte@gmai.com>
> > > > > >>> Tested-by: Martin Ayotte <martinayotte@gmai.com>
> > > > > >> gmai.com is likely a typo.
> > > > > >>
> > > > > >>> On Wed, Jul 31, 2019 at 10:42 PM Chen-Yu Tsai <wens@csie.org
> > > > > >>>
> > > > > >>>> Thanks. The patch looks good overall. The authorship is a little
> > > > > >>>> confusing though. If it was initially done by Martin (CC-ed), then
> > > > > >>>> he should be the author, and we should get his Signed-off-by if
> > > > > >>>> possible.
> > > > > >>
> > > > > >> Martin is indeed the original author of the patch. Thank you for
> > > > > reviewing.
> > > > > >
> > > > > > I'd like to apply this patch with Martin as the author, if that's OK with
> > > > > you
> > > > > > both?
> > > > >
> > > > > That is completely okay with me.
> > > >
> > > > Applied for 5.4.
> > > >
> > > > I reordered the tags so they make more sense:
> > > >
> > > > https://git.kernel.org/pub/scm/linux/kernel/git/sunxi/linux.git/commit/?h=sunxi/dt-for-5.4&id=0834887732df5af41b59b2e4d530fc1f5478965f
> > >
> > > Sorry for being late on this, but it looks like the eMMC, NAND and SPI
> > > pins are conflicting on the A64-Olinuxino design.
> > >
> > > There's no configuration with a NAND, so we don't really need to worry
> > > about that, but if we merge this in the main DT, we'll prevent anyone
> > > from using that DT on an olinuxino with a SPI flash.
> > >
> > > I think we should just create emmc and SPI-flash variants of that DT.
> >
> > Actually they aren't. Olimex specifically uses eMMC modules that don't
> > use the data strobe line, so SPI can be used together.
>
> Ah, right.
>
> Still, this creates a precedent that I'm not really comfortable
> with. Three actually.
>
> Merging this in the main DT means three things:
>   - We're not consistent anymore, including within the olinuxino
>     boards only. A20 Olinuxino is pretty much in the same situation,
>     yet we dealt with it differently.
>   - This means that this will create a spurious device and report
>     errors in the kernel message and whenever someone will try to
>     access the device on boards that don't have it wired. This
>     shouldn't happen and we really shouldn't expose devices that just
>     aren't there, just like you don't have all the devices that are
>     not connected on your USB connector.
>   - Finally, this means that in order to keep it somewhat consistent,
>     we would have to merge the SPI flash in the main DT too. This will
>     prevent people without a SPI flash to use the SPI signals on the
>     UEXT connector for something else, which again goes against the
>     policy we've had for basically any other board.

OK. Shall we back it out and figure out something else?

ChenYu

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