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authorRussell King <rmk@dyn-67.arm.linux.org.uk>2006-04-15 15:46:11 -0400
committerRussell King <rmk+kernel@arm.linux.org.uk>2006-04-15 15:46:11 -0400
commit67ab7f596b6adbaef5abc539dbee822e298a36e1 (patch)
tree83c36f0d9f2f9b82f8747e38302f601f9408a7af /Documentation/serial/driver
parent2c5362007bc0a46461a9d94958cdd53bb027004c (diff)
[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 <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'Documentation/serial/driver')
-rw-r--r--Documentation/serial/driver22
1 files changed, 18 insertions, 4 deletions
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 @@
3 -------------------- 3 --------------------
4 4
5 5
6 $Id: driver,v 1.10 2002/07/22 15:27:30 rmk Exp $
7
8
9This document is meant as a brief overview of some aspects of the new serial 6This document is meant as a brief overview of some aspects of the new serial
10driver. It is not complete, any questions you have should be directed to 7driver. It is not complete, any questions you have should be directed to
11<rmk@arm.linux.org.uk> 8<rmk@arm.linux.org.uk>
12 9
13The reference implementation is contained within serial_amba.c. 10The reference implementation is contained within amba_pl011.c.
14 11
15 12
16 13
@@ -31,6 +28,11 @@ The serial core provides a few helper functions. This includes identifing
31the correct port structure (via uart_get_console) and decoding command line 28the correct port structure (via uart_get_console) and decoding command line
32arguments (uart_parse_options). 29arguments (uart_parse_options).
33 30
31There is also a helper function (uart_write_console) which performs a
32character by character write, translating newlines to CRLF sequences.
33Driver writers are recommended to use this function rather than implementing
34their own version.
35
34 36
35Locking 37Locking
36------- 38-------
@@ -86,6 +88,7 @@ hardware.
86 - TIOCM_DTR DTR signal. 88 - TIOCM_DTR DTR signal.
87 - TIOCM_OUT1 OUT1 signal. 89 - TIOCM_OUT1 OUT1 signal.
88 - TIOCM_OUT2 OUT2 signal. 90 - TIOCM_OUT2 OUT2 signal.
91 - TIOCM_LOOP Set the port into loopback mode.
89 If the appropriate bit is set, the signal should be driven 92 If the appropriate bit is set, the signal should be driven
90 active. If the bit is clear, the signal should be driven 93 active. If the bit is clear, the signal should be driven
91 inactive. 94 inactive.
@@ -141,6 +144,10 @@ hardware.
141 enable_ms(port) 144 enable_ms(port)
142 Enable the modem status interrupts. 145 Enable the modem status interrupts.
143 146
147 This method may be called multiple times. Modem status
148 interrupts should be disabled when the shutdown method is
149 called.
150
144 Locking: port->lock taken. 151 Locking: port->lock taken.
145 Interrupts: locally disabled. 152 Interrupts: locally disabled.
146 This call must not sleep 153 This call must not sleep
@@ -160,6 +167,8 @@ hardware.
160 state. Enable the port for reception. It should not activate 167 state. Enable the port for reception. It should not activate
161 RTS nor DTR; this will be done via a separate call to set_mctrl. 168 RTS nor DTR; this will be done via a separate call to set_mctrl.
162 169
170 This method will only be called when the port is initially opened.
171
163 Locking: port_sem taken. 172 Locking: port_sem taken.
164 Interrupts: globally disabled. 173 Interrupts: globally disabled.
165 174
@@ -169,6 +178,11 @@ hardware.
169 RTS nor DTR; this will have already been done via a separate 178 RTS nor DTR; this will have already been done via a separate
170 call to set_mctrl. 179 call to set_mctrl.
171 180
181 Drivers must not access port->info once this call has completed.
182
183 This method will only be called when there are no more users of
184 this port.
185
172 Locking: port_sem taken. 186 Locking: port_sem taken.
173 Interrupts: caller dependent. 187 Interrupts: caller dependent.
174 188