I presume there's no problem sharing the binary only driver since being a kernel module it's GPL by inference. (AND STRICTLY SHOULD COME WITH SOURCE).
Linux kernel modules do not have to be released under the GPL. Though Linus frowns on it and attempts to discourage the practice, it is perfectly legal to develop and distribute a non-GPL'd kernel module under a restrictive commercial license and without source code.If this were not the case, there would be no SD drivers of any kind for the Zaurus since joining the SD association and getting the specs required need to write the module forces you to enter into a non-disclosure agreement that prohibits publishing the source for the drivers.