multiple dma engines/ ring buffers

[Henk Medenblik <yoda@deathstar2.nl>]

Hi,

I am struggling with the concept of using two different DMA engines and 
therefore two ring buffer definitions in a single driver.
My purpose is to have two different data paths which I want to select in 
my iio device driver. One of them has the purpose to stream plain ADC 16 
bit data to my backend while the second selection would be a hardware 
FFT core output (complex 32 bit). So which one I stream to the backend 
should be selectable.

Because both paths originate from different parts in my HW design I 
implemented two different DMA engines and therefore I have two different 
dma names. However, how to deal with that in my single driver? Has 
anyone done that?

Regards

Henk