fpc202_write
return fpc202_write(priv, FPC202_REG_OUT_A_OUT_B_VAL, val);
return fpc202_write(priv, FPC202_REG_OUT_A_OUT_B, val);
ret = fpc202_write(priv, reg_mod, val);
ret = fpc202_write(priv, reg_aux, val);