[PATCH v3 0/5] Add generic-display-mux driver and bindings

[Chen-Yu Tsai]

On Thu, Mar 30, 2023 at 2:10 AM Jagan Teki <jagan at amarulasolutions.com> wrote:
>
> On Sat, Feb 18, 2023 at 4:47 PM Pin-yen Lin <treapking at chromium.org> wrote:
> >
> > This series is developed for and tested on MT8173 board, and the layout is:
> >
> >                                   /-- anx7688
> > -- MT8173 HDMI bridge -- GPIO mux
> >                                   \-- native HDMI
>
> What is the part number of this GPIO mux? Does mux gpio interrupt
> based and able to switch output HDMI and DP. If so, how this gpio
> interrupt is different than the HPD in native HDMI? I mean does HPD
> have any detection bottlenecks with mux gpio interrupt?

It's a full blown HDMI 1:2 demultiplexer, so DDC and HPD signals are muxed
as well. The anx7688 handles all the Type-C stuff, and our EC talks to it.
If HDMI output from the SoC needs to be muxed over for DP alt-mode, the EC
will signal the SoC.

> I do have GPIO Mux that input DSI and two outputs DMD/HDMI Input and
> HDMI Out. 2x1 with 1x2 mux.
>
> I'm thinking having a generic mux to select the specific out number of
> outputs with associated interface outputs can be a viable solution to
> address all use cases here.

AFAIK DRM doesn't allow dynamically changing the constitution of a display
pipeline, so it doesn't really work out for us.

If you're just muxing between different outputs with passive/dumb bridges,
it may still work for you.

ChenYu