Right now TinyG has support for PWM on the PWM port. It, by default is set to be used with PWM Speed Controllers / hobby servos etc. In fact OtherLab uses it with an ESC (electronic Speed Controller) for a brushless motor as a spindle.
That being said I would have to see what you are talking about with your choice of a “governor”.
Can you provide more details? I would also like to see what you are making. If you would like to share… Perhaps I can make a blog post or share it on the Synthetos G+ account.
Riley