path: root/Documentation/serial
diff options
authorKevin Cernekee <>2012-12-26 20:43:42 -0800
committerGreg Kroah-Hartman <>2013-01-15 21:57:44 -0800
commite759d7c53b39a43fc908425bf9985b8b7d930550 (patch)
tree1dda0be7eed24d1ac06d43e8dbdd63a924280608 /Documentation/serial
parentef4f527c48c8fcbb5e35dafaef4f9097f5e9d901 (diff)
tty: Update serial core API documentation
Signed-off-by: Kevin Cernekee <> Acked-by: Alan Cox <> Signed-off-by: Greg Kroah-Hartman <>
Diffstat (limited to 'Documentation/serial')
1 files changed, 39 insertions, 0 deletions
diff --git a/Documentation/serial/driver b/Documentation/serial/driver
index a6ef8dc436f1..067c47d46917 100644
--- a/Documentation/serial/driver
+++ b/Documentation/serial/driver
@@ -133,6 +133,16 @@ hardware.
Interrupts: locally disabled.
This call must not sleep
+ send_xchar(port,ch)
+ Transmit a high priority character, even if the port is stopped.
+ This is used to implement XON/XOFF flow control and tcflow(). If
+ the serial driver does not implement this function, the tty core
+ will append the character to the circular buffer and then call
+ start_tx() / stop_tx() to flush the data out.
+ Locking: none.
+ Interrupts: caller dependent.
Stop receiving characters; the port is in the process of
being closed.
@@ -254,6 +264,10 @@ hardware.
Locking: none.
Interrupts: caller dependent.
+ set_wake(port,state)
+ Enable/disable power management wakeup on serial activity. Not
+ currently implemented.
Return a pointer to a string constant describing the specified
port, or return NULL, in which case the string 'unknown' is
@@ -306,6 +320,31 @@ hardware.
Locking: none.
Interrupts: caller dependent.
+ poll_init(port)
+ Called by kgdb to perform the minimal hardware initialization needed
+ to support poll_put_char() and poll_get_char(). Unlike ->startup()
+ this should not request interrupts.
+ Locking: tty_mutex and tty_port->mutex taken.
+ Interrupts: n/a.
+ poll_put_char(port,ch)
+ Called by kgdb to write a single character directly to the serial
+ port. It can and should block until there is space in the TX FIFO.
+ Locking: none.
+ Interrupts: caller dependent.
+ This call must not sleep
+ poll_get_char(port)
+ Called by kgdb to read a single character directly from the serial
+ port. If data is available, it should be returned; otherwise
+ the function should return NO_POLL_CHAR immediately.
+ Locking: none.
+ Interrupts: caller dependent.
+ This call must not sleep
Other functions