tty: uart: custom speed

[Subhashini Rao Beerisetty]

 Hi All,


I’ve an UART ports on Xilinx FPGA board and it gets connected to PC
via PCIe bus. I could not find any kernel serial driver which supports
our hardware so I plan to develop a new driver. I see two approaches
to develop an UART driver i.e. either by using tty_register_driver()
or an uart_register_driver().


Regarding my UART module, it has a counter of 16 bits and runs on a
32Mhz clock. It supports all the standard & non-standard baud’s up to
4Mbps.


If I used struct tty_operations, I noticed that baud rate changing is
done via “.set_termios” API, but this method only supports standard
baud rates. I’d like to know why this API does not support
non-standard baud rates?


Okay, what methods a good driver should implement to support
non-standard baud rates?

Thanks