Setting up and using SPI with DMA on a STM32F4

[ZassiM]

Hi everyone.
I have an STM32F4 which communicates to an AD converter via SPI. The AD provides 2 samples, each 16 bit, for every cycle. I can configure the data rate of the AD by using a PWM timer. By detecting the BUSY pin of the AD, I could trigger an interrupt for incoming samples.
For improving the efficiency of the overall system I might want to use the DMA during sampling. I have some buffers with a certain size which should be filled by the DMA. However, I didn't manage to make it working. I added the KConfig option CONFIG_SPI_STM32_DMA=y, and enabled the DMA on devicetree. But I find difficulties understanding how to use the SPI API with the DMA enabled. In theory, I should give to the DMA the memory address of the buffer, its length, and the memory increment offset. How can this be done on Zephyr?

I appreciate any help and suggestion.