  We propose a new quantization rule which generates Landau levels consistent
with the zero-field magnetic response functions from the semiclassical theory.
It reproduces the Onsager's rule in the leading order, and re-formulates
corrections from the Berry phase and magnetic moment effect in terms of one
single magnetic response: the zero-field magnetization. It can yield higher
order corrections by including successively magnetic susceptibility and higher
order magnetic response functions. In application, it can be easily applied to
obtain Landau levels in lattice models. Moreover, it provides an experimental
method of measuring different magnetic response functions directly from the
measurement of Landau level fan diagram or Hofstadter spectrum.
