PORT_BACK_PRESSURE
ksz_port_cfg(dev, port, REG_PORT_MAC_CTRL_1, PORT_BACK_PRESSURE, true);
lan937x_port_cfg(dev, port, REG_PORT_MAC_CTRL_1, PORT_BACK_PRESSURE,
KS8842_PORT_CTRL_2_OFFSET, PORT_BACK_PRESSURE, set);