[PATCH v13 3/4] gpio: rpmsg: add generic rpmsg GPIO driver

[Mathieu Poirier]

On Mon, 11 May 2026 at 12:18, Andrew Lunn <andrew at lunn.ch> wrote:
>
> > Arnaud, Beleswar, Andrew and I are all advocating for one endpoint per
> > GPIO controller.  The remaining issue it about the best way to work
> > out source and destination addresses between Linux and the remote
> > processor.  I'm running out of time for today but I'll return to this
> > thread with a final analysis by the end of the week.
>
> How many of the participants here will be in Minneapolis next week for
> the Embedded Linux Conference? There is even a talk about this:
>
> https://osselcna2026.sched.com/event/2JQpx/building-virtual-drivers-with-rpmsg-key-design-principles-challenges-trade-offs-beleswar-prasad-padhi-texas-instruments?iframe=yes&w=100%&sidebar=yes&bg=no
>
> Maybe we can get together and decide on the final design after the
> session.
>

I will not be in Minneapolis next week.  At this point I think things
are converging into 2 main takeaways:

1) A serious refactoring of the protocol to include only what is
available in the virtio-gpio specification [1].
2) The specification of GPIO controller number in an extension of the
namespace announcement [2].

Shenwei proposed embedding the GPIO controller number in the
endpoint's source address [3], something I'm ambivalent about and
still have to look into.  I also have to read Tanmay's latest
comments.  I'm hoping to be done with all that by the end of the week.
With the above (1) and (2), a new patchset will be required to reset
this thread.

Thanks,
Mathieu

[1]. https://lwn.net/ml/all/afjyH5JT0JS2j0L5@p14s/
[2]. https://lwn.net/ml/all/afzIABSh1xtMEGbf%40p14s/
[3]. https://lwn.net/ml/all/PAXPR04MB9185BFA6E7375FAD0B15B021893C2@PAXPR04MB9185.eurprd04.prod.outlook.com/

>         Andrew