PHY_CSR4
reg = rt2500usb_register_read(rt2x00dev, PHY_CSR4);
rt2500usb_register_write(rt2x00dev, PHY_CSR4, reg);
rt2x00mmio_register_write(rt2x00dev, PHY_CSR4, reg);
rt2x00mmio_regbusy_read((__dev), PHY_CSR4, PHY_CSR4_BUSY, (__reg))
rt2x00usb_register_write_lock(rt2x00dev, PHY_CSR4, reg);
rt2x00usb_regbusy_read((__dev), PHY_CSR4, PHY_CSR4_BUSY, (__reg))