Compute Module • Re: How to Enable DSI1 on Raspberry Pi CM4 (Debian Bookworm) with DS90UH941AS + DS90UH948

Questions:
1. How can I properly enable DSI1 with my custom configuration on the Raspberry Pi CM4?

You write a driver for the DS90UH941AS and DS90UH948, and create the appropriate chain of bridges and panel in device tree.

2. Do I need to modify the device tree overlay (`dtoverlay`)?

You need to create your own overlay that describes the hardware configuration, yes.

3. How do I ensure the Raspberry Pi outputs the correct timing over DSI to my DS90UH941AS?

Your panel definition in device tree should be set to define the appropriate timings.

4. What additional configurations or drivers are needed for proper synchronization?

A driver for each FPDLink device, and a dtoverlay configuring DSI->DS90UH941AS->DS90UH948->panel should do the trick.

Does the DS90UH948 get configuration over the FPDLink from the DS90UH941AS? If not then things could be interesting.

If you have a search on these forums, you'll find the threads where aBUGSworstnightmare has sorted the relevant device tree overlay required for the TI SN65DSI83 DSI to LVDS bridge. Your setup isn't that dissimilar, but needs an extra node in the chain.

Statistics: Posted by 6by9 — Thu Mar 20, 2025 6:12 pm

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