[PATCH v11 20/24] arm64: dts: rockchip: enable vop2 and hdmi tx on rock-3a

[Piotr Oniszczuk]

> Wiadomość napisana przez Peter Geis <pgwipeout at gmail.com> w dniu 09.05.2022, o godz. 18:00:
> 
> If you want to confirm the hardware is configured correctly you can
> remove the cec pin from the hdmi node and set up a cec-gpio node.
> https://elixir.bootlin.com/linux/v5.18-rc5/source/Documentation/devicetree/bindings/media/cec-gpio.txt

Peter, Sascha

I configured cec-gpio and can confirm: with gpio cec works on my rock3-a board v1.31.

So summarising my tests:

                                        rock3-a v1.1   rock3-a v1.31   rock3-b

radxa debian:                               ok             ok                ok

other ppl mainline 5.18:               ok             n/t                n/t

me with mainline 5.18:                 n/t            nok              ok

me with mainline 5.18 gpio-cec:  n/t             ok                n/t

Non-working combination is: rock3-a v1.31 hw on mainline 5.18. 
For me it looks like there is bug in case when rk3568 using cec on hdmitxm1_cec line.
(The same binaries working ok on my rock3-b where cec is on hdmitxm0_cec line. It also works on Peter's rock3a v1.1 - which also uses hdmitxm0_cec line).

It looks like upper cec driver can talk to lower driver (dw-hdmi?) but nothing is received from lower driver, as my app says:
CECAdapter: CEC device can't poll TV: TV does not respond to CEC polls

btw: I verified with oscilloscope connected to hdmitxm1_cec line: starting cec-compliance -v -T shows expected series of 0V pulses on hdmitxm1_cec line....