mavlink: Add flow control parameters (#19254)

src/modules/mavlink/module.yaml

@@ -24,6 +24,14 @@ serial_config:
         then
             set MAV_ARGS "${MAV_ARGS} -s"
         fi
+        if param compare MAV_${i}_FLOW_CTRL 0
+        then
+            set MAV_ARGS "${MAV_ARGS} -Z"
+        fi
+        if param compare MAV_${i}_FLOW_CTRL 1
+        then
+            set MAV_ARGS "${MAV_ARGS} -z"
+        fi
         mavlink start ${MAV_ARGS} -x
       port_config_param:
         name: MAV_${i}_CONFIG
@@ -153,3 +161,18 @@ parameters:
             num_instances: *max_num_config_instances
             default: [1, 0, 0]
             requires_ethernet: true
+
+        MAV_${i}_FLOW_CTRL:
+            description:
+                short: Enable serial flow control for instance ${i}
+                long: |
+                    This is used to force flow control on or off for the the mavlink
+                    instance. By default it is auto detected. Use when auto detction fails.
+
+            type: enum
+            values:
+                0: Force off
+                1: Force on
+                2: Auto-detected
+            num_instances: *max_num_config_instances
+            default: [2, 2, 2]