> It seems RZ/G1C has two slighty different types of SD card interfaces:
>   1. SDHI0 and SDHI2 use SYS-DMAC,
>   2. SDHI1 can also be used as an MMC interface, and has an internal DMAC.
> 
> Do we need to distinguish between them using the compatible value, or
> are there other ways?

Yes, that seems to need an update to our current implementation which is
per-SoC only. One idea from my side would be to whitelist SYS-DMAC for
this compatible and then check if dma-properties are present, otherwise
fall back to internal DMAC?

Fabrizio, did you have any plans how to handle that?