GMAC_CLK_SRC
val &= ~(GMAC_CLK_PIT|GMAC_CLK_SRC);
val |= __SHIFTIN(GMAC_CLK_SRC_MII, GMAC_CLK_SRC);
val |= __SHIFTIN(GMAC_CLK_SRC_RGMII, GMAC_CLK_SRC);