WM8776_CLOCK_RATIO_256FS
ratio = WM8776_CLOCK_RATIO_256FS;
if (adc_ratio < WM8776_CLOCK_RATIO_256FS)
adc_ratio = WM8776_CLOCK_RATIO_256FS;
if (adc_ratio == WM8776_CLOCK_RATIO_256FS)