[SERIAL] Update serial_core documentation
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/Documentation/serial/driver b/Documentation/serial/driver
index 87856d3..42ef997 100644
--- a/Documentation/serial/driver
+++ b/Documentation/serial/driver
@@ -116,12 +116,15 @@
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 @@
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 @@
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
-----------
