diff options
| -rw-r--r-- | Documentation/serial/driver | 66 |
1 files changed, 57 insertions, 9 deletions
diff --git a/Documentation/serial/driver b/Documentation/serial/driver index 87856d3cfb67..42ef9970bc86 100644 --- a/Documentation/serial/driver +++ b/Documentation/serial/driver @@ -116,12 +116,15 @@ hardware. line becoming inactive or the tty layer indicating we want to stop transmission due to an XOFF character. + The driver should stop transmitting characters as soon as + possible. + Locking: port->lock taken. Interrupts: locally disabled. This call must not sleep start_tx(port) - start transmitting characters. + Start transmitting characters. Locking: port->lock taken. Interrupts: locally disabled. @@ -281,26 +284,31 @@ hardware. Other functions --------------- -uart_update_timeout(port,cflag,quot) +uart_update_timeout(port,cflag,baud) Update the FIFO drain timeout, port->timeout, according to the - number of bits, parity, stop bits and quotient. + number of bits, parity, stop bits and baud rate. Locking: caller is expected to take port->lock Interrupts: n/a -uart_get_baud_rate(port,termios) +uart_get_baud_rate(port,termios,old,min,max) Return the numeric baud rate for the specified termios, taking account of the special 38400 baud "kludge". The B0 baud rate is mapped to 9600 baud. + If the baud rate is not within min..max, then if old is non-NULL, + the original baud rate will be tried. If that exceeds the + min..max constraint, 9600 baud will be returned. termios will + be updated to the baud rate in use. + + Note: min..max must always allow 9600 baud to be selected. + Locking: caller dependent. Interrupts: n/a -uart_get_divisor(port,termios,oldtermios) - Return the divsor (baud_base / baud) for the selected baud rate - specified by termios. If the baud rate is out of range, try - the original baud rate specified by oldtermios (if non-NULL). - If that fails, try 9600 baud. +uart_get_divisor(port,baud) + Return the divsor (baud_base / baud) for the specified baud + rate, appropriately rounded. If 38400 baud and custom divisor is selected, return the custom divisor instead. @@ -308,6 +316,46 @@ uart_get_divisor(port,termios,oldtermios) Locking: caller dependent. Interrupts: n/a +uart_match_port(port1,port2) + This utility function can be used to determine whether two + uart_port structures describe the same port. + + Locking: n/a + Interrupts: n/a + +uart_write_wakeup(port) + A driver is expected to call this function when the number of + characters in the transmit buffer have dropped below a threshold. + + Locking: port->lock should be held. + Interrupts: n/a + +uart_register_driver(drv) + Register a uart driver with the core driver. We in turn register + with the tty layer, and initialise the core driver per-port state. + + drv->port should be NULL, and the per-port structures should be + registered using uart_add_one_port after this call has succeeded. + + Locking: none + Interrupts: enabled + +uart_unregister_driver() + Remove all references to a driver from the core driver. The low + level driver must have removed all its ports via the + uart_remove_one_port() if it registered them with uart_add_one_port(). + + Locking: none + Interrupts: enabled + +uart_suspend_port() + +uart_resume_port() + +uart_add_one_port() + +uart_remove_one_port() + Other notes ----------- |