PORT_PHY_LOOPBACK  303 drivers/net/dsa/microchip/ksz8795_reg.h #define PORT_PHY_LOOPBACK		BIT(7)
PORT_PHY_LOOPBACK  880 drivers/net/dsa/microchip/ksz9477_reg.h #define PORT_PHY_LOOPBACK		BIT(14)