44 lines
1.6 KiB
Diff
44 lines
1.6 KiB
Diff
From 1c5d969f46ccd5333f602dfbe2b0a1295650b9b0 Mon Sep 17 00:00:00 2001
|
|
From: =?UTF-8?q?St=C3=A9phane=20Raimbault?= <stephane.raimbault@gmail.com>
|
|
Date: Wed, 25 Oct 2017 20:35:47 +0200
|
|
Subject: [PATCH 1/2] Only set SER_RS485_ENABLED bit of existing RS485 settings
|
|
|
|
Thanks to @JCWren
|
|
---
|
|
src/modbus-rtu.c | 10 +++++++++-
|
|
1 file changed, 9 insertions(+), 1 deletion(-)
|
|
|
|
diff --git a/src/modbus-rtu.c b/src/modbus-rtu.c
|
|
index 8d9f386..f2911d6 100644
|
|
--- a/src/modbus-rtu.c
|
|
+++ b/src/modbus-rtu.c
|
|
@@ -909,9 +909,13 @@ int modbus_rtu_set_serial_mode(modbus_t *ctx, int mode)
|
|
#if HAVE_DECL_TIOCSRS485
|
|
modbus_rtu_t *ctx_rtu = ctx->backend_data;
|
|
struct serial_rs485 rs485conf;
|
|
- memset(&rs485conf, 0x0, sizeof(struct serial_rs485));
|
|
|
|
if (mode == MODBUS_RTU_RS485) {
|
|
+ // Get
|
|
+ if (ioctl(ctx->s, TIOCGRS485, &rs485conf) < 0) {
|
|
+ return -1;
|
|
+ }
|
|
+ // Set
|
|
rs485conf.flags = SER_RS485_ENABLED;
|
|
if (ioctl(ctx->s, TIOCSRS485, &rs485conf) < 0) {
|
|
return -1;
|
|
@@ -923,6 +927,10 @@ int modbus_rtu_set_serial_mode(modbus_t *ctx, int mode)
|
|
/* Turn off RS485 mode only if required */
|
|
if (ctx_rtu->serial_mode == MODBUS_RTU_RS485) {
|
|
/* The ioctl call is avoided because it can fail on some RS232 ports */
|
|
+ if (ioctl(ctx->s, TIOCGRS485, &rs485conf) < 0) {
|
|
+ return -1;
|
|
+ }
|
|
+ rs485conf.flags &= ~SER_RS485_ENABLED;
|
|
if (ioctl(ctx->s, TIOCSRS485, &rs485conf) < 0) {
|
|
return -1;
|
|
}
|
|
--
|
|
2.21.0
|
|
|