From 67ab7f596b6adbaef5abc539dbee822e298a36e1 Mon Sep 17 00:00:00 2001 From: Russell King Date: Sat, 15 Apr 2006 20:46:11 +0100 Subject: [SERIAL] Update serial driver documentation Improve serial driver documentation: - Remove CVS id. - Update pointer to reference driver documentation. - Add comments about new uart_write_console function. - Add TIOCM_LOOP modem control bit description. - Add commentry about enable_ms method being called multiple times. - Add commentry about startup/shutdown method calling. - Mention that dereferencing port->info after shutdown is invalid. Signed-off-by: Russell King --- Documentation/serial/driver | 22 ++++++++++++++++++---- 1 file changed, 18 insertions(+), 4 deletions(-) (limited to 'Documentation') diff --git a/Documentation/serial/driver b/Documentation/serial/driver index 42ef9970bc86..df82116a9f26 100644 --- a/Documentation/serial/driver +++ b/Documentation/serial/driver @@ -3,14 +3,11 @@ -------------------- - $Id: driver,v 1.10 2002/07/22 15:27:30 rmk Exp $ - - This document is meant as a brief overview of some aspects of the new serial driver. It is not complete, any questions you have should be directed to -The reference implementation is contained within serial_amba.c. +The reference implementation is contained within amba_pl011.c. @@ -31,6 +28,11 @@ The serial core provides a few helper functions. This includes identifing the correct port structure (via uart_get_console) and decoding command line arguments (uart_parse_options). +There is also a helper function (uart_write_console) which performs a +character by character write, translating newlines to CRLF sequences. +Driver writers are recommended to use this function rather than implementing +their own version. + Locking ------- @@ -86,6 +88,7 @@ hardware. - TIOCM_DTR DTR signal. - TIOCM_OUT1 OUT1 signal. - TIOCM_OUT2 OUT2 signal. + - TIOCM_LOOP Set the port into loopback mode. If the appropriate bit is set, the signal should be driven active. If the bit is clear, the signal should be driven inactive. @@ -141,6 +144,10 @@ hardware. enable_ms(port) Enable the modem status interrupts. + This method may be called multiple times. Modem status + interrupts should be disabled when the shutdown method is + called. + Locking: port->lock taken. Interrupts: locally disabled. This call must not sleep @@ -160,6 +167,8 @@ hardware. state. Enable the port for reception. It should not activate RTS nor DTR; this will be done via a separate call to set_mctrl. + This method will only be called when the port is initially opened. + Locking: port_sem taken. Interrupts: globally disabled. @@ -169,6 +178,11 @@ hardware. RTS nor DTR; this will have already been done via a separate call to set_mctrl. + Drivers must not access port->info once this call has completed. + + This method will only be called when there are no more users of + this port. + Locking: port_sem taken. Interrupts: caller dependent. -- cgit v1.2.3-59-g8ed1b