who wrote the spi extended functionality for Arduino Due ARMSAM,

I am trying to interface a codec (WM8731) to Due and facing problems in SPI. Could some one guide or tell me who wrote the library for Extended SPI functionality for Due?I need help.

All of the code is published on Github. You could go back through the history for that file and find which Github user pushed those changes. I suspect that person may only have pasted in the example code from Atmel, then other people will have edited it.

What is the actual problem you are having?

(And don't be surprised if a moderator moves this to the Due sub-forum.)