RT715_SDCA_DB_STEP
reg_val = gain_sft - reg_val / RT715_SDCA_DB_STEP;
reg_val = gain_sft + reg_val / RT715_SDCA_DB_STEP;
((abs(u_ctrl_val - vol_gain_sft) * RT715_SDCA_DB_STEP) << 8) / 1000;