I now decided to use a more general variable name and as Marek suggested the checks against the given define-values. This should keep the structure of several "vis-modes" in general, as it had been done before by Simon, instead of just "on" and "off".
The checkpatch-script from the batman-adv linux git branch showed me 0 errors/warnings for this one.
- So far, just had the time to test this patch with my laptop and home-server only. But switching as well as receiving/displaying the vis-stuff worked fine for those (didn't have a closer look with tcpdump/wireshark for this vis-type part though).
Cheers, Linus