How to AddDriver:
First, make sure the driver is compatible with the current CVS version of comedi, or at least compatible with the latest release 0.7.75.
The usual method is to enter it as a new bug in Comedi's bugzilla: https://bugzilla.comedi.org/cgi-bin/bugzilla/enter_bug.cgi
You can file the bug under the "Comedi" product. This may prompt you to log in to bugzilla. If you haven't logged in before, you'll need to create a bugzilla account using the "New Account" link at the bottom of the page: https://bugzilla.comedi.org/cgi-bin/bugzilla/createaccount.cgi
Once logged in you can enter the bug for the Comedi product. Set the Version to "CVS" and the Component to "Misc drivers". Enter a Summary and Description. After Committing the bug, you can add the source code files and patches as attachments.
You don't need to worry too much about submitting patches for the Makefiles and Kbuild files etc. This can be sorted out by the Comedi maintainers once the driver has been reviewed and accepted. If you need to change any of the Comedi core files or header files, you will need to submit patches for those.