I created a simple kernel driver for hd44780-based LCD displays using GPIO pins.
You can get it from SVN:
$ cd trunk/packages
$ svn co http://linux-adm5120.svn.sourceforge.ne … rt/hd44780
You will need to edit the source to change pins to suit your router.
It can be tested with:
echo -n "hello world" >> /dev/hd44780.
It's very basic, and doesn't handle control codes, but may be of use all the same.