MIICMD
bcmmdio_write_4(sc, MIICMD, MIICMD_RD(phy, reg));
int val = __SHIFTOUT(bcmmdio_read_4(sc, MIICMD), MIICMD_DATA);
bcmmdio_write_4(sc, MIICMD, MIICMD_WR(phy, reg, val));