Comment 7 for bug 1008345

also need to look into this commit

commit 1c0035d710dd3bfa86d58f851b8737c7f11a9bbc
Author: Shawn Guo <email address hidden>
Date: Thu Apr 12 20:50:18 2012 +0800

    clk: pass parent_rate into .set_rate

    For most of .set_rate implementation, parent_rate will be used, so just
    like passing parent_rate into .recalc_rate, let's pass parent_rate into
    .set_rate too.

    It also updates the kernel doc for .set_rate ops.