__pll_params_to_rate
now = __pll_params_to_rate(parent_rate, m, n, 0, pll);
round = __pll_params_to_rate(req->best_parent_rate, m, n, 0, pll);
req->rate = __pll_params_to_rate(req->best_parent_rate, m, n, frac, pll);
return __pll_params_to_rate(parent_rate, m, n, frac, pll);