ETH_USB_CFG0
if ((err = lan78xx_read_reg(sc, ETH_USB_CFG0, &buf)) != 0) {
lan78xx_write_reg(sc, ETH_USB_CFG0, buf);
if ((err = lan78xx_read_reg(sc, ETH_USB_CFG0, &buf)) < 0) {
err = lan78xx_write_reg(sc, ETH_USB_CFG0, buf);