The IOWarrior Driver

General
IOWarrior is the name of a series of multi-purpose USB controller chips produced and sold by Code Mercenaries. This series currently consists of three main types, that - among other features - support controlling LCD displays:
IOWarrior24 	
USB 1.1 Low Speed
16 generic I/O Pins, typ. 125Hz read rate
I2C master function, 100kHz, throughput typ. 750 bytes/sec
SPI master interface, up to 2MHz, throughput typ. 750 bytes/sec
control an HD44780 compatible LCD
drive a matrix of up to 8x32 LEDs
decode RC5 compatible infrared remote controls
IOWarrior40 	
USB 1.1 Low Speed
32 generic I/O Pins, typ. 125Hz read rate
I2C master function, 100kHz, throughput typ. 750 bytes/sec
control an HD44780 compatible LCD
drive a matrix of up to 8x32 LEDs
drive a 8x8 switch or button matrix
IOWarrior56 	
USB 1.1 Full Speed
50 generic I/O Pins, typ. 1000Hz read rate
I2C master function, 50, 100, or 400kHz
SPI master interface, up to 12MHz, throughput up to 62Kbytes/sec
control various display modules, including most graphic modules
drive a matrix of up to 8x64 LEDs
drive a 8x8 switch or button matrix
The IOWarrior driver currently only supports writing to a single-controller HD44780-type display. LED output using the output() function is also implemented, although not tested very well. The hardware's support for input using keys or IR and dual-controller displays is not implemented yet. Please note that the latter requires extra circuitry with IOWarrior24 and IOWarrior40.
The driver was developed and tested with IOWarrior24 and the IOWarrior40. Although there are good chances for it to work with an IOWarrior56, the current state regarding support of this chip is unknown due to the lack of the required hardware.

Requirements
The driver is based on the libusb USB library, which should make it work with Linux, the different BSD variants as well as Darwin/MacOS X.
When using a libusb based driver like IOWarrior, LCDd needs to be started as root.
Newer Linux kernels (2.6.20 and higher) provide a kernel module iowarrior.ko that allows controlling IOWarrior chips using device files. LCDd tries to unload this kernel module for libusb to be able to control IOWarrior devices. If this fails, this may hinder LCDd from starting using the IOWarrior driver. In this case, simply unload the kernel module by hand.

Configuration in LCDd.conf

[IOWarrior]
Size = 	 Set the display dimensions. If not given, it defaults to 20x4.
SerialNumber = SERIALNO 	 Use the IOWarrior module with the serial number SERIALNO. If this parameter is missing, the default is to use the first IOWarrior module found.
ExtendedMode = 	 If you have a KS0073 or an other 'almost HD44780-compatible' display connected to the IOWarrior, set this flag to get into extended, 4-line linear addressing mode
Lastline = 	 Specifies if the last line is pixel addressable or it controls an underline effect. The default yes means, it is pixel addressable.