[PATCH v3 6/8] ARM: zte: Bring back zx29 UART support

Linus Walleij linusw at kernel.org
Tue Apr 21 01:55:05 PDT 2026


On Mon, Apr 20, 2026 at 11:22 PM Stefan Dösinger
<stefandoesinger at gmail.com> wrote:

> > Interesting with the AMBA pseudo-ID, but I kind of like the idea.
>
> It wasn't my idea. That's - as the description says - the code that was once
> upstream before it got removed in 89d4f98ae90d. This is also why the
> ZX_UART011_* defines still exist.

Aha!

> I re-checked if the device identifies itself in the mmio area in any way, and
> that I maybe got the size wrong - but that was not the case, everything past
> the ZX_UART011_* registers is zero until the next device starts.

Yeah it's common that vendors just forget about this and set it all
to zero.

> Another idea I considered is using ZTE's 0x8c (assuming that "Microelectronics
> Institute ZTE" is the same ZTE that made the board), but then I would have to
> invent a device number, ideally without clashing with an existing ZTE device.

I think that's a great idea! At least that is what was supposed to be done,
maybe the ZTE HW engineers will get the message one day.

Yours,
Linus Walleij



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