Hi,
As for the naming, we typically avoid driver names with Xs in them. But rather name them by the first component that is supported or by the component that is for example a super set of the other components. In the adau1761 case the adau1761 is the adau1361 + sigmadsp, hence the driver is called adau1761. It also supports the automotive versions of these chips. Same for the adau1781. The adau17x1 is a helper module that contains code that is shared between the adau1761 and the adau1781.
The MIC bias is turned on by using DAPM. In your board driver you create a route from the MICBIAS widget to your microphone widgets that need the MICBIAS supply. And whenever the microphone is in use the MICBIAS widget will be powered up as well. You can use the zed_adau1761 driver as an example.
The PLL registers are programmed when the PLL is enabled, are you trying to reprogram the PLL while it is enabled?
If I understand you correctly the ALC clock needs to be enabled so that the manual gain changes are applied?
The unconditional digmic mode assignment is clearly a bug, I'll fix it, thanks.
- Lars