Re: [PATCH v2] arm64: dts: rockchip: add spdif sound node for rock64

[Katsuhiro Suzuki]

Hello,

Sorry for late, thank you for your comments.

On 2018å10æ03æ 18:53, Chen-Yu Tsai wrote:
> Hi,
>
> On Mon, Sep 17, 2018 at 8:28 PM Katsuhiro Suzuki
> <katsuhiro@xxxxxxxxxxxxx> wrote:
> > This patch adds sound card node for rock64. Currently we can support
> > S/PDIF only. It seems the lack of codec driver of rk3328 to enable
> > analog audio out.
> >
> > Signed-off-by: Katsuhiro Suzuki <katsuhiro@xxxxxxxxxxxxx>
> > ---
> >   .../arm64/boot/dts/rockchip/rk3328-rock64.dts | 29 +++++++++++++++++++
> >   1 file changed, 29 insertions(+)
> >
> > diff --git a/arch/arm64/boot/dts/rockchip/rk3328-rock64.dts b/arch/arm64/boot/dts/rockchip/rk3328-rock64.dts
> > index 5852061e497b..9ee4f57557f3 100644
> > --- a/arch/arm64/boot/dts/rockchip/rk3328-rock64.dts
> > +++ b/arch/arm64/boot/dts/rockchip/rk3328-rock64.dts
> > @@ -62,6 +62,23 @@
> >                  regulator-min-microvolt = <5000000>;
> >                  regulator-max-microvolt = <5000000>;
> >          };
> > +
> > +       sound {
> > +               compatible = "audio-graph-card";
> > +               label = "rockchip,rk3328";
>
> I understand that this patch has been merged. However, seeing this label
> I wonder how this works when the analog codec and HDMI audio out are added,
> and how userspace is supposed to select an output.

I don't know detail of HDMI audio of RK3328, but maybe it has cpu or 
codec DAIs. The audio-graph-card is supporting to use multiple DAIs on
a card. This is same as simple-audio-card.

For example, add I2S0 device as hw:X,0
(and move SPDIF to hw:X,0 -> hw:X,1)

sound {
	compatible = "audio-graph-card";
	label = "rockchip,rk3328";
	dais = <&i2s0_p0
		&spdif_p0>;
};

&i2s0 {
	status = "okay";
	#sound-dai-cells = <0>;

	i2s0_p0: port {
		i2s0_p0_0: endpoint {
			dai-format = "i2s";
			remote-endpoint = <&some_codec_abcd>;
		};
	};
};

We should write special card driver for RK3328 sound if audio-graph-card
is not enough to deal with HDMI audio.


> On the side, it seems that extra codecs, such as the rock64 add-on board,
> are easier dealt with by adding a separate simple-audio-card node to couple
> the codec and i2s nodes.

I think multiple DAIs on single card and single DAI on multiple cards
are both OK to work. But I cannot decide the way for this issue.


> ChenYu

Regards,
--
Katsuhiro Suzuki