Re: [alsa-devel] [PATCH v2 3/5] ASoC: core: add support to snd_soc_dai_get_sdw_stream()

[Srinivas Kandagatla <srinivas.kandagatla@linaro.org>]

On 13/08/2019 18:51, Pierre-Louis Bossart wrote:
> On 8/13/19 11:50 AM, Srinivas Kandagatla wrote:
>> Thanks for the review,
>>
>> On 13/08/2019 15:44, Pierre-Louis Bossart wrote:
>>> On 8/13/19 3:35 AM, Srinivas Kandagatla wrote:
>>>> On platforms which have smart speaker amplifiers connected via
>>>> soundwire and modeled as aux devices in ASoC, in such usecases machine
>>>> driver should be able to get sdw master stream from dai so that it can
>>>> use the runtime stream to setup slave streams.
>>>
>>> using the _set_sdw_stream? I don't fully get the sequence with the 
>>> wording above.
>>
>> Yes, using set_sdw_stream().
> 
> Maybe I am missing something here, but I don't see where the 
> set_sdw_stream() is called.

sorry for the confusion. It was too quick reply. :-)
I was suppose to say sdw_stream_add_slave() instead of set_sdw_stream().

As Aux device is dailess there is no way to get hold of sdw stream 
runtime for slave device associated with it.

Having snd_soc_dai_get_sdw_stream() would help machine driver to get 
hold of sdw_stream_runtime from controller dai and setup slave streams 
using sdw_stream_add_slave().


thanks,
srini


> 
> Also I don't fully get the rule. set_sdw_stream() looks required, 
> get_sdw_stream() is optional, is this what you are suggesting?
> 
>>>
>>>>
>>>> soundwire already as a set function, get function would provide more
>>>> flexibility to above configurations.
>>>
>>> I am not clear if you are asking for both to be used, or get only or 
>>> set only?
>>
>> It depends on the usecase, in db845c usecase  [1] as Aux device is dai 
>> less, machine driver is using get function to get hold of master 
>> stream so that it can setup slave port config.
>>
>>
>> Looks like there is a typo in above like
>>
>> This was supposed to be "soundwire already has a set function, get 
>> function would provide more flexibility to above configurations"
>>
>> [1] 
>> https://git.linaro.org/landing-teams/working/qualcomm/kernel.git/tree/sound/soc/qcom/db845c.c?h=integration-linux-qcomlt 
>>
>>
>> thanks,
>> srini
>>
>>>
>>>>
>>>> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
>>>> ---
>>>>   include/sound/soc-dai.h | 10 ++++++++++
>>>>   1 file changed, 10 insertions(+)
>>>>
>>>> diff --git a/include/sound/soc-dai.h b/include/sound/soc-dai.h
>>>> index dc48fe081a20..1e01f4a302e0 100644
>>>> --- a/include/sound/soc-dai.h
>>>> +++ b/include/sound/soc-dai.h
>>>> @@ -202,6 +202,7 @@ struct snd_soc_dai_ops {
>>>>       int (*set_sdw_stream)(struct snd_soc_dai *dai,
>>>>               void *stream, int direction);
>>>> +    void *(*get_sdw_stream)(struct snd_soc_dai *dai, int direction);
>>>>       /*
>>>>        * DAI digital mute - optional.
>>>>        * Called by soc-core to minimise any pops.
>>>> @@ -410,4 +411,13 @@ static inline int 
>>>> snd_soc_dai_set_sdw_stream(struct snd_soc_dai *dai,
>>>>           return -ENOTSUPP;
>>>>   }
>>>> +static inline void *snd_soc_dai_get_sdw_stream(struct snd_soc_dai 
>>>> *dai,
>>>> +                           int direction)
>>>> +{
>>>> +    if (dai->driver->ops->get_sdw_stream)
>>>> +        return dai->driver->ops->get_sdw_stream(dai, direction);
>>>> +    else
>>>> +        return ERR_PTR(-ENOTSUPP);
>>>> +}
>>>> +
>>>>   #endif
>>>>
>>>
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>