I40E_PRTDCB_RETSC_ETS_MAX_EXP_MASK
reg &= ~I40E_PRTDCB_RETSC_ETS_MAX_EXP_MASK;
reg |= FIELD_PREP(I40E_PRTDCB_RETSC_ETS_MAX_EXP_MASK, max_exponent);