Man page 9 : uart_get_baud_rate

uart_get_baud_rate - return baud rate for a particular port

unsigned int uart_get_baud_rate(struct uart_port *  port , struct ktermios *  termios , struct ktermios *  old , unsigned int  min , unsigned int  max );

port
    uart_port structure describing the port in question.

termios
    desired termios settings.

old
    old termios (or NULL)

min
    minimum acceptable baud rate

max
    maximum acceptable baud rate

Decode the termios structure into a numeric baud rate, taking account of the magic 38400 baud rate (with spd_* flags), and mapping the B0 rate to 9600 baud.

If the new baud rate is invalid, try the old termios setting. If itAqs still invalid, we try 9600 baud.

Update the termios structure to reflect the baud rate weAqre actually going to be using. DonAqt do this for the case where B0 is requested (« hang up »).