Talking SPI from AR9311

On the Arduino side is:

The SPI pins are also connected to the AR9331 gpio pins, where it has been implemented in software the SPI interface. This means that the ATMega32u4 and the AR9331 can also communicate using the SPI protocol.

How does one write for the gpio pins on the AR9311?

The SPI pins are also connected to the AR9331 gpio pins, where it has been implemented in software the SPI interface. This means that the ATMega32u4 and the AR9331 can also communicate using the SPI protocol.

It is software SPI since AR9331 has no SPI interface.

http://arduino.cc/en/Products/ArduinoYUN#.UwNkafldX04

Anybody have sample code for the AR9311 side to read or write to GPIO pins?

Maybe you could start here: http://linino.org/doku.php?id=wiki:spidriverstream#the_spi_tty_driver_and_the_stream_spi And try getting the source code using git.