CCM_FRAC_PLL_REFCLK_DIV_VAL_MASK
CCM_FRAC_PLL_REFCLK_DIV_VAL_MASK;
reg &= ~(CCM_FRAC_PLL_REFCLK_DIV_VAL_MASK << CCM_FRAC_PLL_REFCLK_DIV_VAL_SHIFT);