firmata-pi
A firmata device implementation for the raspberry pi's gpio. Major parts of this was lifted from node-firmata.
This is a work in progress.
As for the behavior of the device, I'm copying from the arduino firmata which is well written but not documented.
The firmata-pi library is a node stream. You write fimrata midi commands and it responds as a device would. Eventually it should include a stream for reading off the gpio's serial port.
This approch will allow it to be substitued as the serial port in other projects such as node-firmata or johnny-five. This will let you run johny-five locally on a raspberry pi without the need for an arduino.