diff options
Diffstat (limited to 'Documentation/serial/driver')
| -rw-r--r-- | Documentation/serial/driver | 31 |
1 files changed, 23 insertions, 8 deletions
diff --git a/Documentation/serial/driver b/Documentation/serial/driver index 42ef9970bc86..88ad615dd338 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 <rmk@arm.linux.org.uk> -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. @@ -200,12 +214,13 @@ hardware. The interaction of the iflag bits is as follows (parity error given as an example): Parity error INPCK IGNPAR - None n/a n/a character received - Yes n/a 0 character discarded - Yes 0 1 character received, marked as + n/a 0 n/a character received, marked as + TTY_NORMAL + None 1 n/a character received, marked as TTY_NORMAL - Yes 1 1 character received, marked as + Yes 1 0 character received, marked as TTY_PARITY + Yes 1 1 character discarded Other flags may be used (eg, xon/xoff characters) if your hardware supports hardware "soft" flow control. |