[SERIAL] Update serial_core documentation

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

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
 -----------