AP_IOMCU: Add binding procedure for DSMx

libraries/AP_IOMCU/AP_IOMCU.cpp

@@ -784,6 +784,20 @@ void AP_IOMCU::shutdown(void)
     }
 }
 
+/*
+  request bind on a DSM radio
+ */
+void AP_IOMCU::bind_dsm(uint8_t mode)
+{
+    if (config.protocol_version != IOMCU_PROTOCOL_VERSION ||
+        hal.util->get_soft_armed()) {
+        // only with ChibiOS IO firmware, and disarmed
+        return;
+    }
+    uint16_t reg = mode;
+    write_registers(PAGE_SETUP, PAGE_REG_SETUP_DSM_BIND, &reg);
+}
+
 /*
   setup for mixing. This allows fixed wing aircraft to fly in manual
   mode if the FMU dies

libraries/AP_IOMCU/AP_IOMCU.h

@@ -65,6 +65,9 @@ public:
      */
     bool check_rcinput(uint32_t &last_frame_us, uint8_t &num_channels, uint16_t *channels, uint8_t max_channels);
 
+    // Do DSM receiver binding
+    void bind_dsm(uint8_t mode);
+
     /*
       get servo rail voltage
      */