[PATCH] dts: Re-add aliases for imx6qdl-sabrelite devices

[Fabio Estevam]

On Mon, Dec 5, 2022 at 12:37 PM Tom Rini <trini at konsulko.com> wrote:

> I'm not really happy with this approach.  It's not that upstream doesn't
> have aliases now, it's that it has different aliases, right? That's why
> they won't accept these?

imx6q.dtsi does have the default mmc aliases:

mmc0 = &usdhc1;
mmc1 = &usdhc2;
mmc2 = &usdhc3;
mmc3 = &usdhc4;

Upstream does not want to change mmc alias because users may rely on
this mmc aliases.

Changing it now may cause the board not to boot anymore as the rootfs
cannot be found.

It is OK to change mmc alias for a newly introduced board, but please
keep in mind that
wandboard and sabrelite have been launched many many years ago.

So for upstream Linux the message was clear: don't change the mmc
alias for these boards.

Now let's talk about U-Boot.

Prior to d0399a46e7cd ("imx6dl/imx6qdl: synchronise device trees with
linux") the mmc alias for sabrelite was present:

               mmc0 = &usdhc3;
               mmc1 = &usdhc4;

After this commit, the mmc alias is gone and causes the boot
regression as reported by Detlev.

We don't want to cause regressions in U-Boot as well, so that's why I
propose just adding the alias into u-boot.dtsi.

There are many boards that does the same.

> But this also highlights that we really need to get these kind of
> aliases and similar (a) re-synced with upstream ASAP and (b) do that at

imx6 dts files are already synced with Linux.

> the start. I don't know which group of "users are broken by this change"
> is bigger, the group that needs the aliases we have or the group that
> needs the other aliases, but the group that gets changes upstream first
> "wins" here is how the OSS world works.

I prefer to not break things for anyone, hence my proposal.

If you are still not happy with it, please feel free to submit a patch
with your proposal.