Re: Debugging CPU-side DAI hardware with a dummy codec

[Nicolas Frattaroli <nicolas.frattaroli@collabora.com>]

On Thursday, 10 April 2025 13:23:21 Central European Summer Time Nicolas Frattaroli wrote:
> On Thursday, 10 April 2025 12:54:16 Central European Summer Time Daniel Baluta wrote:
> > > > I hope someone can shed some light on this, as it seems like something audio
> > > > controller developers would be doing all the time.
> > >
> > > I suspect most people test with an actual system.  A bunch of things get
> > > easier if you can actually play and record sound.
> > 
> > Mark, that's true in most of the cases. But for silicon IP
> > pre-validation using emulation
> > environments most of the SoC creators use a synthetic codec so things like being
> > able to probe a dummy-codec does make some sense.
> > 
> > Nicolas,
> > 
> > Can you please paste your patches (dts and the rest)?
> > 
> > thanks,
> > Daniel.
> > 
> 
> Hi Daniel,
> 
> I'll send the test-component changes in a proper patch submission later.
> 
> The DTS in my case looks like this though. `sai0` here is the SoC-side
> audio interface. Don't worry about the pinctrl/dma overriding, that's
> me disabling capture.
> 
> ---
> diff --git a/arch/arm64/boot/dts/rockchip/rk3576-armsom-sige5.dts b/arch/arm64/boot/dts/rockchip/rk3576-armsom-sige5.dts
> index de63b053a06c..6e78713b1a99 100644
> --- a/arch/arm64/boot/dts/rockchip/rk3576-armsom-sige5.dts
> +++ b/arch/arm64/boot/dts/rockchip/rk3576-armsom-sige5.dts
> @@ -84,6 +84,25 @@ simple-audio-card,codec {
>  		};
>  	};
>  
> +	dummy_codec: dummy-codec {
> +		compatible = "test-codec-verbose";
> +		dai-tdm-slot-num = <8>;
> +		dai-tdm-slot-width = <16>;
> +		#sound-dai-cells = <0>;
> +
> +		port {
> +			codec_endpoint: endpoint {
> +				remote-endpoint = <&sai0_endpoint>;
> +			};
> +		};
> +	};

Gah, major blunder from my side, the dai-tdm-slot-* properties should be
inside the endpoint node of the codec here like this:

	dummy_codec: dummy-codec {
		compatible = "test-codec-verbose";
		#sound-dai-cells = <0>;

		port {
			codec_endpoint: endpoint {
				dai-tdm-slot-num = <8>;
				dai-tdm-slot-width = <16>;
				remote-endpoint = <&sai0_endpoint>;
			};
		};
	};

Sorry about the confusion.

Cheers,
Nicolas Frattaroli

> [...]
> 
> Cheers,
> Nicolas Frattaroli