From ddc50a8420f41cf8b326a452ffc1de663e6a65be Mon Sep 17 00:00:00 2001
From: bugobliterator <siddharthbharatpurohit@gmail.com>
Date: Mon, 26 Jul 2021 16:17:06 +0530
Subject: [PATCH] AP_GPS: add option to set a dedicated line for Moving
 Baseline Data

---
 libraries/AP_GPS/AP_GPS.cpp        | 4 ++--
 libraries/AP_GPS/AP_GPS_UAVCAN.cpp | 4 ++--
 libraries/AP_GPS/GPS_Backend.h     | 1 +
 3 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/libraries/AP_GPS/AP_GPS.cpp b/libraries/AP_GPS/AP_GPS.cpp
index a50bcdc460..26a3538efa 100644
--- a/libraries/AP_GPS/AP_GPS.cpp
+++ b/libraries/AP_GPS/AP_GPS.cpp
@@ -183,7 +183,7 @@ const AP_Param::GroupInfo AP_GPS::var_info[] = {
     // @Param: _AUTO_CONFIG
     // @DisplayName: Automatic GPS configuration
     // @Description: Controls if the autopilot should automatically configure the GPS based on the parameters and default settings
-    // @Values: 0:Disables automatic configuration,1:Enable automatic configuration,2:Enable automatic configuration for UAVCAN as well
+    // @Values: 0:Disables automatic configuration,1:Enable automatic configuration for Serial GPSes only,2:Enable automatic configuration for UAVCAN as well
     // @User: Advanced
     AP_GROUPINFO("_AUTO_CONFIG", 13, AP_GPS, _auto_config, 1),
 
@@ -300,7 +300,7 @@ const AP_Param::GroupInfo AP_GPS::var_info[] = {
     // @Param: _DRV_OPTIONS
     // @DisplayName: driver options
     // @Description: Additional backend specific options
-    // @Bitmask: 0:Use UART2/2nd CAN for moving baseline on ublox/uavcan,,1:Use base station for GPS yaw on SBF,2:Use baudrate 115200
+    // @Bitmask: 0:Use UART2 for moving baseline on ublox,1:Use base station for GPS yaw on SBF,2:Use baudrate 115200,3:Use dedicated CAN port b/w GPSes for moving baseline
     // @User: Advanced
     AP_GROUPINFO("_DRV_OPTIONS", 22, AP_GPS, _driver_options, 0),
 #endif
diff --git a/libraries/AP_GPS/AP_GPS_UAVCAN.cpp b/libraries/AP_GPS/AP_GPS_UAVCAN.cpp
index 44774f0c95..e7c4fcdd95 100644
--- a/libraries/AP_GPS/AP_GPS_UAVCAN.cpp
+++ b/libraries/AP_GPS/AP_GPS_UAVCAN.cpp
@@ -894,14 +894,14 @@ bool AP_GPS_UAVCAN::handle_param_get_set_response_int(AP_UAVCAN* ap_uavcan, uint
     }
 
     if (strcmp(name, "GPS_MB_ONLY_PORT") == 0 && cfg_step == STEP_SET_MB_CAN_TX) {
-        if (gps._driver_options == 0 && value != 1) {
+        if ((gps._driver_options & UAVCAN_MBUseDedicatedBus) && !value) {
             // set up so that another CAN port is used for the Moving Baseline Data
             // setting this value will allow another CAN port to be used as dedicated
             // line for the Moving Baseline Data
             value = 1;
             requires_save_and_reboot = true;
             return true;
-        } else if (gps._driver_options != 0 && value != 0) {
+        } else if (!(gps._driver_options & UAVCAN_MBUseDedicatedBus) && value) {
             // set up so that all CAN ports are used for the Moving Baseline Data
             value = 0;
             requires_save_and_reboot = true;
diff --git a/libraries/AP_GPS/GPS_Backend.h b/libraries/AP_GPS/GPS_Backend.h
index a78bf38088..6510482ad8 100644
--- a/libraries/AP_GPS/GPS_Backend.h
+++ b/libraries/AP_GPS/GPS_Backend.h
@@ -88,6 +88,7 @@ public:
         UBX_MBUseUart2    = (1U << 0U),
         SBF_UseBaseForYaw = (1U << 1U),
         UBX_Use115200     = (1U << 2U),
+        UAVCAN_MBUseDedicatedBus  = (1 << 3U),
     };
 
 protected: