[LV2] Nonlinear value mapping of control ports

[Dominique Würtz]

Hi,
I've just started to look into porting some of my VST2 plugins to LV2.
One thing I couldn't figure out so far is how to specify a custom non-
linear value mapping for a control port. To me it seems LV2 only offers
linear and logarithmic scaling. In my plugins, some controls use a
exponential-like scaling curve with a custom mid point. Can I do this
with LV2?
Thanks,
Dominique