iris_opp_set_rate
ret = iris_opp_set_rate(core->dev, freq);
ret = iris_opp_set_rate(core->dev, ULONG_MAX);
ret = iris_opp_set_rate(core->dev, 0);
int iris_opp_set_rate(struct device *dev, unsigned long freq);
iris_opp_set_rate(core->dev, 0);
iris_opp_set_rate(core->dev, freq);