Commit 6056f20f authored by Crescent CY Hsieh's avatar Crescent CY Hsieh Committed by Greg Kroah-Hartman
Browse files

tty: serial: Add RS422 flag to struct serial_rs485 



Add "SER_RS485_MODE_RS422" flag to struct serial_rs485, so that serial
port can switch interface into RS422 if supported by using ioctl command
"TIOCSRS485".

By treating RS422 as a mode of RS485, which means while enabling RS422
there are two flags need to be set (SER_RS485_ENABLED and
SER_RS485_MODE_RS422), it would make things much easier. For example
some places that checks for "SER_RS485_ENABLED" won't need to be rewritten.

Signed-off-by: default avatarCrescent CY Hsieh <crescentcy.hsieh@moxa.com>
Link: https://lore.kernel.org/r/20231201071554.258607-3-crescentcy.hsieh@moxa.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 76ac8e29

drivers/tty/serial/serial_core.c

+6 −0
Original line number Diff line number Diff line
@@ -1370,6 +1370,12 @@ static void uart_sanitize_serial_rs485(struct uart_port *port, struct serial_rs4 
		return;

	}



	/* Clear other RS485 flags but SER_RS485_TERMINATE_BUS and return if enabling RS422 */

	if (rs485->flags & SER_RS485_MODE_RS422) {

		rs485->flags &= (SER_RS485_ENABLED | SER_RS485_MODE_RS422 | SER_RS485_TERMINATE_BUS);

		return;

	}



	/* Pick sane settings if the user hasn't */

	if ((supported_flags & (SER_RS485_RTS_ON_SEND|SER_RS485_RTS_AFTER_SEND)) &&

	    !(rs485->flags & SER_RS485_RTS_ON_SEND) ==

include/uapi/linux/serial.h

+2 −0
Original line number Diff line number Diff line
@@ -138,6 +138,7 @@ struct serial_icounter_struct { 
 * * %SER_RS485_ADDRB		- Enable RS485 addressing mode.

 * * %SER_RS485_ADDR_RECV - Receive address filter (enables @addr_recv). Requires %SER_RS485_ADDRB.

 * * %SER_RS485_ADDR_DEST - Destination address (enables @addr_dest). Requires %SER_RS485_ADDRB.

 * * %SER_RS485_MODE_RS422	- Enable RS422. Requires %SER_RS485_ENABLED.

 */

struct serial_rs485 {

	__u32	flags;
@@ -149,6 +150,7 @@ struct serial_rs485 { 
#define SER_RS485_ADDRB			_BITUL(5)

#define SER_RS485_ADDR_RECV		_BITUL(6)

#define SER_RS485_ADDR_DEST		_BITUL(7)

#define SER_RS485_MODE_RS422		_BITUL(8)



	__u32	delay_rts_before_send;

	__u32	delay_rts_after_send;