Dear Greg KH, I am Kumaravel Thiagarajan from Microchip India. We are working on a PCIe based multi-instance UART device. Based on the Linux community feedback few months back, we had written it as a custom driver inside drivers/tty/serial/8250. Now this custom driver is requiring a DWORD FIFO access for both Tx and Rx, and I am in the process of changing my driver code. Can I model my custom driver on serial drivers present in drivers/tty/serial/ directory? I am implementing my functions for uart_ops structure and the necessary ISR in a separate file mchp_pci1xxxx_uart.c inside the drivers/tty/serial/ directory. I wish this custom UART driver to get through Linux community submission. Do you see any risk in this approach? Do you have any suggestions? Thank You. Regards, Kumaravel Thiagarajan Technical staff Engineer - Software Microchip India Private Limited, Chennai, India