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From:   Daniel Baluta <daniel.baluta@gmail.com>
Date:   Tue, 21 Nov 2023 16:02:43 +0200
Message-ID: <CAEnQRZD8zbgRzBrx+iHTbDqG5tOedNLyJByNNtSHTRtxFsgyGw@mail.gmail.com>
Subject: Re: [RFC PATCH] ASoC: simple-card: Use dai_id from node description
To:     Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Cc:     Daniel Baluta <daniel.baluta@oss.nxp.com>,
        "broonie@kernel.org" <broonie@kernel.org>,
        "alsa-devel@alsa-project.org" <alsa-devel@alsa-project.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "iuliana.prodan@nxp.com" <iuliana.prodan@nxp.com>,
        "shengjiu.wang@nxp.com" <shengjiu.wang@nxp.com>
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On Tue, Nov 21, 2023 at 1:04=E2=80=AFAM Kuninori Morimoto
<kuninori.morimoto.gx@renesas.com> wrote:
>
> Hi Daniel, Mark
>
> > > > -     args.args_count =3D (of_graph_get_endpoint_count(node) > 1);
> > > > +     args.args_count =3D (of_graph_get_endpoint_count(node) >=3D 1=
);
> > >
> > > If my understanding was correct, for example you want to use 2nd DAI
> > > but your DT has only 1 port (thus, it is using reg property) ?
> >
> > Yes.
>
> But hmm... in your case, you need to setup 2ports, and use 2nd port
> is assumed approach.
> Why you don't setup full port ? Do you have some reason ??

I'm not sure I understand what is a full port setup. But let me
describe my scenario so that we have a common ground.

I want to use audio-graph-card2 machine driver to setup Sound Open
Firrmware cards.

Here we start with a normal link with the following components:

Component 0 (DAI) : 3b6e8000.dsp (See sound/soc/sof/core.c: 280)
                                  -> for imx8m this has 3 statically
defined DAIs
See sound/soc/sof/imx/imx8m.c:

static struct snd_soc_dai_driver imx8m_dai[] =3D {
{     // DAI with index 0
=C2=BB       .name =3D "sai1",
},
{      // DAI with index 1
=C2=BB       .name =3D "sai3",
},
{ /   // DAI with index 2
=C2=BB       .name =3D "micfil",
},
};

Component 1 (Codec): wm8960-hifi
                                    -> with 1 DAI

static struct snd_soc_dai_driver wm8960_dai =3D {
=C2=BB       .name =3D "wm8960-hifi",
};

Now, I want to write a DTS description where my DAI link uses
Component 0 (CPU) (with its DAI index 1) connected with Component 1
(codec) (with its DAI index 0).

So, for this I use the following dts snippet:

sof-sound-wm8960 {
=C2=BB       =C2=BB       compatible =3D "audio-graph-card2";
=C2=BB       =C2=BB       links =3D <&cpu>;
}

dsp: dsp@3b6e8000 {
    cpu: port@1 {
=C2=BB       =C2=BB       reg =3D <1>;
=C2=BB       =C2=BB       cpu_ep: endpoint { remote-endpoint =3D <&codec_ep=
>; };
=C2=BB       };
}

wm8960 {

=C2=BB       port {
=C2=BB       =C2=BB       codec_ep: endpoint { remote-endpoint =3D <&cpu_ep=
>; };
=C2=BB       };
}

So, property reg =3D <1> refferes to DAI with index 1 associated with
component DSP.