[alsa-devel] [PATCH] asoc: add dummy codec

[Stas Sergeev]

11.04.2013 19:48, Gabriel M. Beddingfield пишет:
> On 04/11/2013 08:11 AM, Stas Sergeev wrote:
>>> There is already a dummy codec driver.
>>>
>>> Please take a look at sound/soc/soc-utils.c
>>>
>>> - Lars
>> Lars, indeed, this codec is present in a git kernel and
>> it wasn't in mine android kernel.
>> But, that driver is too dummy to even work at all.
>>
>> The attached patch adds a playback stream for the dummy
>> codec. Would it be possible to apply this?
> No... not like that.
>
> Instead, wouldn't it be better to extend it by defining some platform data?  Maybe something like:
>
> diff --git a/sound/soc/soc-utils.c b/sound/soc/soc-utils.c
> index fe4541d..9d22718 100644
> --- a/sound/soc/soc-utils.c
> +++ b/sound/soc/soc-utils.c
> @@ -96,9 +96,14 @@ static struct snd_soc_dai_driver dummy_dai = {
>  
>  static int snd_soc_dummy_probe(struct platform_device *pdev)
>  {
> +       struct snd_soc_dummy_dai_pdata *pdata = dev_get_platdata(&pdev->dev);
>         int ret;
>  
> -       ret = snd_soc_register_codec(&pdev->dev, &dummy_codec, &dummy_dai, 1);
> +       if (pdata->n_dai > 0)
> +               ret = snd_soc_register_codec(&pdev->dev, &dummy_codec,
> +                                            &pdata->dai, &pdata->n_dai);
> +       else
> +               ret = snd_soc_register_codec(&pdev->dev, &dummy_codec, &dummy_dai, 1);
>         if (ret < 0)
>                 return ret;
>  
>
> ...then you can define whatever kind of DAI you want in the machine driver.
But that's a _dummy_ codec, it simply does this:
---
soc_dummy_dev = platform_device_alloc("snd-soc-dummy", -1);
if (!soc_dummy_dev)
return -ENOMEM;
ret = platform_device_add(soc_dummy_dev);
---
in the very same source file.
What is the reason of adding platform data for a dummy driver?
The code snippet I propose, is copied from the spdif_receiver.c,
so its not something I invented myself. :)