When I try to probe the adau1702 codec from Linux, it complains that it can't find the firmware "adau1701.bin".
If you inspect the kernel driver for the adau1701 https://github.com/torvalds/linux/blob/master/sound/soc/codecs/adau1701.c
On line 884 it attempts to load this file (which it can't find) and fails. This skips line 891 which registers the codec with the ALSA system.
Is it possible to use the ADAU1702 chip initially without firmware ? For example, as a straight through device (no processing) ... that is I2S input to DAC output and ADC input to I2S output ?
If not, is it possible to generate a generic SigmaDSP firmware which will achieve this ? Unfortunately SigmaDSP doesn't run on Linux (I have a request for porting it to Linux already made).