No Audio from CircuitCo B1 CODEC

Beaglebone Black Rev C1
Debian 8.6 IOT version 2016-11-06
CircuitCo Audio Cape B1

After a long weekend, finally got the Audio Cape B1 overlay to load without errors.

But, no audio comes out.

Reading the overlay file source, it indicates that the McASP audio transfer format is I2S.

Which would be fine, if it were true.

Putting an oscilloscope on the McASP clock and data leads says the actual transfer format being used is ‘DSP’ which is another standard, but incompatible format.

I suspect that the CODEC and the McASP are configured for different transfer formats.

Where can I go to read the source files that configure the Sitara McASP module?
Where are the source files that configure the CODEC via the I2C bus?
Are these compiled into the kernel?
Or, are there associated editable configuration files that I can use to configure the McASP and the CODEC without having to recompile the kernel?

— Graham