Reversing lin-to-log patch

Hi all,

I was lucky enough to find this incredibly useful little patch which applies an exponential curve to linear steams of values from dials, etc:

What I need to do now is reverse this process; I've trawled the web quite a bit and can't seem to find anything which does exactly what I need.
As far as I can see, the maths used here (where x is the linear data & y is the logarithmic equivalent) is:
y=2^(0.052456x)
I've tried rearranging this in all sorts of ways to make x the subject but have to admit that my maths isn't all that great these days, so any light anyone would be willing to shed on this would be much appreciated.

Thanks!