Zero 3W; Using the 22-Pin MIPI CSI for touchscreen?

[InfiniteBSOD]

Hello,

Since the Zero 3W has a 22-Pin MIPI CSI (4-lane) I was wondering if it could be used to connect a touchscreen such as the Radxa Display 10 FHD?

It (Zero 3W) isn’t listed as compatible for the monitor and checking the Zero 2 Pro which is listed compatible:
31-pin MIPI CSI
39-pin MIPI DSI

So I don’t know the first thing about MIPI but DSI seems to be short for “Display Serial Interface” and CSI to be short for “Camera Serial Interface”.

So there is a hardware limitation for this in the Zero 3W so it will (never) be supported?
Looking for an easy way to connect a touchscreen that supports orientation.

Best Regards

[Histo_Shape]

Ooops, me too - getting a 4"&5" round TOUCH Display and thought to drive them with ZERO or ROCK 3E.
We will see 🤷🏻

[Frankie_Yuen]

Hello have you had any success?

[Histo_Shape]

So far no success connecting the DSI display to Radxa Zero or Rock 3c. Either a DSI to DMI board or the corresponding connections on the Radxa’s are missing. The 5" display has an HDMI board & works.

You could or must connect to the Radxa’s via GPIO. This is new territory for me… like the whole topic.
I have ordered 2 other displays that are already connected to Android boards and then try to derive it from them.

It’s tedious how secretive the manufacturers/sellers are - they know the customer’s needs in advance and are too vague about problems. That’s annoying

[Histo_Shape]

[Histo_Shape]

…this is what you get AFTER buying Displays

[Frankie_Yuen]

I am trying to create custom overlay to get the DSI port of Radxa Zero 2 Pro working with the Waveshare 4 inch DSI LCD

Waveshare do push the overlay dts file to Raspberry Pi Linux GitHub here but I am surprised that I cannot find any overlay done by Radxa for Radxa Zero 2 Pro regarding the DSI interface here

As for what you are trying to achieve: If I understand it correctly, you are trying to use the 22 Pin MIPI CSI interface to drive a DSI monitor? AFAIK it’s not possible, at least to my ability. I think for example the Radxa Zero 2 Pro’s MIPI DSI interface routes some of its pins to some kind of DisplayPort while normally a MIPI CSI interface routes it to the SoC’s ISP to process the sensor’s raw data, which is completely different.

If you want to achieve a ‘one cable’ solution for a touch screen for Radxa Zero 3W/E, a custom PCB with a USB and HDM layout and cable-wrap the USB cable and HDMI into one could be a neat solution.

[Histo_Shape]

No…i kniw i cant connet to csi
Radxa boards poorly fit my needs. Got 2 other displays with attached Android boards RK3566/88’s, problem is to connect the other displays via Fpc-30 pins, breakout boards ect blabla - not familiar to that stuff. All that connectors

[Frankie_Yuen]

I got a custom panel working with a Raspberry Pi 5, using some breakout boards to match the pin mapping between the panel and the host. And MIPI DSI is definitely not plug and play, I had to write my own panel driver and implement the touch panel driver from some Android source and then write my own device tree overlay to make it work in mainline Linux kernel.

Now moving on to make a customised PCB with IO expander to save some GPIO pins from the 40-pin GPIO.

Current Linux and for Radxa / Rockchip is not mainline, but somehow Rockchip included a ‘generic’ DSI driver in their kernel device tree but I am not sure how well it works (I highly doubt it is generic as most panels will have different ways of initialisation for example)