[alsa-devel] simple-card: DAI link creation

[alsa-devel] simple-card: DAI link creation

[Daniel Baluta]

Hello Morimoto-san,

I want to know your opinion on enhancing simple-card in order to be
able to create
more flexible links.

So far, simple-card allows the following cases:

1) normal sound

all DAIs are detected as CPU - Codec (+optional platform).

2) DPCM sound

2a) all CPUs are detected CPU - <dummy_codec> [FE]
2b) all codecs are detected <dummy_cpu> - codec [BE]

I will need to have a third case where I need to create
a back end link like this:

link->cpus->of_node  = <&my_dai>;
link->codecs->of_node = <&my_codec>;
link->platforms->of_node = <&my_platform>;
link->no_pcm = 1;

Somehow, similar with qcom_snd_parse_of from
sound/soc/qcom/common.c.

Do you think it would be OK to create another file to handle this case
in sound/soc/generic?

Also, I would really like one day to really understand the role
of cpu/platform/codec for a FE/BE.

In the case of the FE:
- cpu dai
- platform
- codec, here it makes sense to be dummy codec.

In the case of BE:
- cpu_dai
- platform
- codec, here it make sense to be reference to a real codec

In the case of normal link:
- cpu_dai, here it makes sense is a physical DAI
- platform
- codec, here it makes sense it is a physical codec.

thanks,
Daniel.
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Re: [alsa-devel] simple-card: DAI link creation

[Kuninori Morimoto]

Hi Daniel

Thank you for contacting me

> link->cpus->of_node  = <&my_dai>;
> link->codecs->of_node = <&my_codec>;
> link->platforms->of_node = <&my_platform>;
> link->no_pcm = 1;
> 
> Somehow, similar with qcom_snd_parse_of from
> sound/soc/qcom/common.c.
> 
> Do you think it would be OK to create another file to handle this case
> in sound/soc/generic?

Or having extra flag for it ?

	static const struct of_device_id simple_of_match[] = {
		{ .compatible = "simple-audio-card", },
		{ .compatible = "simple-scu-audio-card",
		  .data = (void *)DPCM_SELECTABLE },
+		{ .compatible = "simple-xxx-audio-card",
+		  .data = (void *)DPCM_WITH_PLATFORM },
		{},
	};

This idea is adding new feature on simple-card.
But, in sound card case, many patterns exist,
thus, adding new feature into simple-card will be difficult.

So having new file is not bad idea.
But, I'm thinking some Card driver want to create new driver,
but want to share simple-card code.
Actually, simple-card-utils.c is for it.
But, maybe someone want to share simple-card.c code itself ?

Some overwrite technic can be nice idea.

# Now I'm focusing cleanup ALSA SoC
# Current framework has "normal sound" and "DPCM sound",
# and it makes code/DT difficult.
# But if all cleanup could be done, these can be merged,
# and can have more flexible connection.
# Then, I want to create new simple-card with *really* simple code :)

Thank you for your help !!
Best regards
---
Kuninori Morimoto
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