DMX USB Driver

The DMX USB driver is a Linux 4.X kernel driver for the Enttec DMX USB dongle ( http://www.enttec.com/dmxusb.php )

Building the driver

Before the driver can be build, the kernel sourcecode needs to be installed. To build the driver just call make, this should build a dmx_usb.ko (the kernel module) and a dmx_usb_test (a small test program).

Building on a RPi4 running Raspbian

First update your RPi with the following commands;

apt-get update -y
apt-get upgrade -y

After that you might want to reboot to make sure you are running the maybe updated kernel.

Than get the kernel source code;

# Get rpi-source
sudo wget https://raw.githubusercontent.com/notro/rpi-source/master/rpi-source -O /usr/bin/rpi-source

# Make it executable
sudo chmod +x /usr/bin/rpi-source

# Tell the update mechanism that this is the latest version of the script
/usr/bin/rpi-source -q --tag-update

# Get the kernel files thingies.
rpi-source

Now you should be ready to build the DMX USB module.

Problems loading the right driver.

A "small" problem to solve was to make the kernel clear that it should use my driver for the dongle and not the standard usbserial driver. Since I don't have any other USBserial devices with the samechip type I just removed the ftdi_sio.ko module, and changed the /etc/hotplug/usb.distmap to point to my module. To support both the ftdi_sio.o module and the dmx_usb.o module the ftdi_sio.o module should be patched and the Product ID for the FT232BM should be removed from it, this will mean all other serial-usb devices are still supported just not the one with FT232BM chips, since it isn't possible to differentiate DMX-USB and normal-serial versions.