Hi Kuninori,

Am 2019-12-03 01:54, schrieb Kuninori Morimoto:

Hi Michael

...

sound { compatible = "simple-audio-card"; simple-audio-card,format = "i2s"; [snip] simple-audio-card,bitclock-master = <&dailink0_master>; simple-audio-card,frame-master = <&dailink0_master>;

simple-audio-card,cpu@0 { sound-dai = <&sai6>; };

simple-audio-card,cpu@1 { sound-dai = <&sai5>; };

dailink0_master: simple-audio-card,codec { sound-dai = <&wm8904>; }; };

Just for the background, I have hardware with the LS1028A which only have unidirectional SAIs. But two of those SAIs (one for playback and one for capture) are connected to one codec (with a shared bit and frame clock).

So I thought the example in the simple-card bindings makes sense for my case. Although I don't really know what "(Mixing)" means.

Nevertheless, using the fragment above, the kernel oopses or fails to probe the hardware. I've traced that back to the following:

• the count is correct: the kernel reports "link 2, dais 3, ccnf

0". please note the 3 dais here.

• but simple_dai_link_of() will always "allocate" two dais from the

pool:

    cpu_dai                 =
    dai_props->cpu_dai      = &priv->dais[li->dais++];
    codec_dai               =
    dai_props->codec_dai    = &priv->dais[li->dais++];

While this still works for the first link, the second one will fail because codec_dai will not be valid.

Btw, converting that to two explicit dai-link nodes, the dai count will be 4 and it will work.

Is my use case correct or should I use the two explicit dai-link nodes? But in any case there seems to be a bug in simple-card.

I guess you want to use "simple-scu-audio-card" instead of "simple-audio-card" in this case ?

sound {

• compatible = "simple-audio-card";
  

• compatible = "simple-scu-audio-card";
  

Thanks, I'll try that tomorrow.

But nevertheless, shouldn't there be a check for a misconfiguration? At least the bindings document should mention that this configuration is only valid for for the "scu" case. Oh and I've just had a look, the compatible string of this configuration is "simple-audio-card" in Documentation/devicetree/bindings/sound/simple-card.txt.

-michael