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-rw-r--r--drivers/tty/serial/serial_core.c6
-rw-r--r--include/uapi/linux/serial.h2
2 files changed, 8 insertions, 0 deletions
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 1147fb1b39f2..d35371c076b2 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -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) ==
diff --git a/include/uapi/linux/serial.h b/include/uapi/linux/serial.h
index 6c75ebdd7797..9086367db043 100644
--- a/include/uapi/linux/serial.h
+++ b/include/uapi/linux/serial.h
@@ -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;