Matplotlib: how to set custom log tickmarks and positions for already log-transformed data

Question

I have some data where the X variable is already on a (natural) log scale. I want a Matplotlib plot that formats the x-axis so that the major and minor ticks appear identical to those that would be given if the X variable is back-transformed to a linear scale, and plt.xscale('log') is used. In other words, I want pretty logarithmic tickmarks and labels, but I definitely don't want to back-transform the underlying data. I guess this involves explicitly setting the tick mark locations and labels. Is there a way to access the algorithm that Matplotlib uses for laying out logarithmically-spaced ticks without setting plt.xscale('log')?