Hi again
According to Documentation/devicetree/bindings/graph.txt section "Links between endpoints", the endpoint/remote-endpoint links are bi-directional and describe the physical links: the audio port of the codec is connected to the audio controller and reverse. There is no reverse link from the codec to the 'simple-card'.
(snip)
The codec associated to the HDMI transmitter declares 2 DAIs. It may choose to define the DAI numbers either in a fixed order (say 0 is always S/PDIF and 1 is always I2S), or dynamically, following the declaration of the ports (in the example, 0 is I2S and 1 is S/PDIF).
My assumption was video/audio are using same port, but indeed we need to care about more.
But, if we need to describe both "video port" and "audio port" separately in graph, simple-card side doesn't need graph style IMO. Because normal phandle style (= non graph style) is working already.
I thought that describing both "video" and "audio" is too much. -> assume that video/audio can share same port -> this patch -> but thoughtless :P
I'm not sure, but do you think snd_soc_get_dai_name()::of_xlate_dai_name can works for us ?
My concern is if audio side need to care/support "formal" graph style, I think all cpu/codec/card driver (and soc-core too ?) need to be updated, but it is too much for me. if fake graph style (like this patch) is OK, I'm happy to hack it more.
This "fake graph style" means it is supporting both graph's "remote-endpoint" and current simple-card's "sound-dai" (= not 100% graph style).