Re: DMA sampling and IIO

[John Syn <john3909@gmail.com>]

On 2/7/14, 5:20 AM, "Mark Brown" <broonie@kernel.org> wrote:

>On Thu, Feb 06, 2014 at 10:15:26PM +0100, Lars-Peter Clausen wrote:
>
>> I guess this is because it is the traditional area where I2S is used
>>and nobody
>> cared so far about using it somewhere else in the context of the Linux
>>kernel.
>> Not having to have a extra layer of abstraction in the middle between
>>ALSA/ASoC
>> and the I2S peripheral driver helped to keep things simple.
>
>Plus many of the uses actually found that the audio APIs were doing
>useful things for them anyway - the DMA bit is reasonably useful way of
>transferring continuous streams of data and nothing much cares if that
>data is actually audio or not so long as the application on top doesn't
>mind.
Hi Mark,

That is interesting. The ADE7878 transmits the measurements as 16
sequential measurements (Voltage A, Voltage B, Voltage C, Current A, etc)
and uses a frame to denote a new set of measurements. Can the audio API
cope with 16 channels and how do I prevent any modification (equalization,
etc) to the measurement data? Also, is it possible to break out these
measurements into separate buffers (Voltage A buffer, Voltage B buffer,
etc)? I guess I would access these measurement in the same way as an audio
application like aplay?

What I don¹t like about this solution is the possibility of missing
samples. In an audio app, this isn¹t so critical, but in my app this would
be a big problem. 

Regards,
John
>