NAU8821_DMIC_SRC_SFT
(speed_selection << NAU8821_DMIC_SRC_SFT));
#define NAU8821_DMIC_SRC_MASK (0x3 << NAU8821_DMIC_SRC_SFT)
#define NAU8821_CLK_DMIC_SRC (0x2 << NAU8821_DMIC_SRC_SFT)