Re: How to use SPI instead of I2C in the Generic Codec Driver?
I guess your choices are:
 As mentioned, modify the code to use SPI instead of I2C
 Use bit-banged I2C on the connections you do have.
Bit banging is slower than a peripheral, but you can do it on any pins. As it's only a control interface, slow occasional access shouldn't be a problem.
To get a useful answer, always state which PIC you are using!