[alsa-devel] [PATCH v3 6/6] ASoC: qdsp6: dt-bindings: Add q6afe pcm dt binding documentation

[Srinivas Kandagatla]

On 12/02/2020 11:01, Adam Serbinski wrote:
>>>
>>> +
>>> + - qcom,pcm-slot-mapping
>>> +    Usage: required for pcm interface
>>
>> Are these not specific to 8k and 16k mode ?
>> We should probably list values for both modes here.
> 
> No, this is just the offset that the audio sample is placed in with 
> respect to a maximum of 4 slots, 16 bits wide, beginning with the sync 
> pulse.


That's not true atleast by the QDSP documentation,
according to it we will use more slots to transfer at higher sample 
rate. ex:
16 kHz data can be transferred using 8 kHz samples in two
slots.

Also there are 32 slots for each of 4 supported channels for PCM AFE port.


> 
> When switching between 8 and 16k sample rate, it is just the sync pulse 
> rate that is changed. The audio sample will be delivered in the same 
> slot, just at a different frequency.