Alsa Driver - sound from gpio

Hi! I'm a newbie on ALSA architecture. I would like to known if it would be possible to create a sound driver for a a PCM sound beeing acquired by the GPIO of a processor, like the ARM of a Beaglebone Black. Beaglebone has more than 32 bits of gpio so I intend to acquire the audio signal through a A/D CI (sigma delta) connected to a FPGA that would provide it to the Beaglebone Black in parallel form (PCM code), through the GPIO. Is that possible? Regards