[SERIAL] Update serial_core documentation

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

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)
+uart_get_divisor(port,baud)
-	Return the divsor (baud_base / baud) for the selected baud rate
+	Return the divsor (baud_base / baud) for the specified baud
-	specified by termios.  If the baud rate is out of range, try
+	rate, appropriately rounded.
-	the original baud rate specified by oldtermios (if non-NULL).
-	If that fails, try 9600 baud.
 
 	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
 -----------