EMAC_TX_DLINE_CODE_MASK
mask |= EMAC_TX_DLINE_STEP_MASK | EMAC_TX_DLINE_CODE_MASK;
val |= FIELD_PREP(EMAC_TX_DLINE_CODE_MASK, priv->tx_delay);
#define EMAC_MAX_DELAY_UNIT FIELD_MAX(EMAC_TX_DLINE_CODE_MASK)