tty: docs: serial/tty, add to ldisc methods

A small addition to the ldisc method descriptions.

Signed-off-by: Tilman Schmidt <tilman@imap.cc>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/Documentation/serial/tty.txt b/Documentation/serial/tty.txt
index 8e65c44..5e5349a 100644 (file)
--- a/Documentation/serial/tty.txt
+++ b/Documentation/serial/tty.txt
@@ -42,7 +42,8 @@ TTY side interfaces:
 open()         -       Called when the line discipline is attached to
                        the terminal. No other call into the line
                        discipline for this tty will occur until it
-                       completes successfully. Can sleep.
+                       completes successfully. Returning an error will
+                       prevent the ldisc from being attached. Can sleep.
 
 close()                -       This is called on a terminal when the line
                        discipline is being unplugged. At the point of
@@ -52,7 +53,7 @@ close()               -       This is called on a terminal when the line
 hangup()       -       Called when the tty line is hung up.
                        The line discipline should cease I/O to the tty.
                        No further calls into the ldisc code will occur.
-                       Can sleep.
+                       The return value is ignored. Can sleep.
 
 write()                -       A process is writing data through the line
                        discipline.  Multiple write calls are serialized
@@ -83,6 +84,10 @@ ioctl()              -       Called when an ioctl is handed to the tty layer
                        that might be for the ldisc. Multiple ioctl calls
                        may occur in parallel. May sleep. 
 
+compat_ioctl() -       Called when a 32 bit ioctl is handed to the tty layer
+                       that might be for the ldisc. Multiple ioctl calls
+                       may occur in parallel. May sleep.
+
 Driver Side Interfaces:
 
 receive_buf()  -       Hand buffers of bytes from the driver to the ldisc