driver version string changes

What is the correct approach in dealing with version strings in drivers?
For my own sanity, I need to change the version string as I make changes
to the driver.  Some drivers and the kernel use a nn.nn.nn format while
others use nn.nn and others use nn.nnsss, where nn is a number and sss is
a character or string.  The pcnet32 does a mixture, and I have recently
added to that inconsistency.

What is the recommendation for version strings in Linux drivers, and what
have I not read that already answers this question?

-- 
Don Fry
brazilnut@us.ibm.com