AP_InertialSensor: VRBRAIN added 3th inertial sensor

libraries/AP_InertialSensor/AP_InertialSensor.h

@@ -14,7 +14,7 @@
 #if CONFIG_HAL_BOARD == HAL_BOARD_PX4 || CONFIG_HAL_BOARD == HAL_BOARD_LINUX || CONFIG_HAL_BOARD == HAL_BOARD_AVR_SITL
 #define INS_MAX_INSTANCES 3
 #elif CONFIG_HAL_BOARD == HAL_BOARD_VRBRAIN
-#define INS_MAX_INSTANCES 2
+#define INS_MAX_INSTANCES 3
 #else
 #define INS_MAX_INSTANCES 1
 #endif

libraries/AP_InertialSensor/AP_InertialSensor_VRBRAIN.cpp

@@ -22,17 +22,27 @@ uint16_t AP_InertialSensor_VRBRAIN::_init_sensor( Sample_rate sample_rate )
     // assumes max 2 instances
     _accel_fd[0] = open(ACCEL_DEVICE_PATH, O_RDONLY);
     _accel_fd[1] = open(ACCEL_DEVICE_PATH "1", O_RDONLY);
+    _accel_fd[2] = open(ACCEL_DEVICE_PATH "2", O_RDONLY);
     _gyro_fd[0] = open(GYRO_DEVICE_PATH, O_RDONLY);
     _gyro_fd[1] = open(GYRO_DEVICE_PATH "1", O_RDONLY);
+    _gyro_fd[2] = open(GYRO_DEVICE_PATH "2", O_RDONLY);
 
-	if (_accel_fd[0] < 0) {
+    _num_accel_instances = 0;
+    _num_gyro_instances = 0;
+    for (uint8_t i=0; i<INS_MAX_INSTANCES; i++) {
+        if (_accel_fd[i] >= 0) {
+            _num_accel_instances = i+1;
+        }
+        if (_gyro_fd[i] >= 0) {
+            _num_gyro_instances = i+1;
+        }
+    }    
+	if (_num_accel_instances == 0) {
         hal.scheduler->panic("Unable to open accel device " ACCEL_DEVICE_PATH);
     }
-	if (_gyro_fd[0] < 0) {
+	if (_num_gyro_instances == 0) {
         hal.scheduler->panic("Unable to open gyro device " GYRO_DEVICE_PATH);
     }
-    _num_accel_instances = _accel_fd[1] >= 0?2:1;
-    _num_gyro_instances  = _gyro_fd[1]  >= 0?2:1;
 
     switch (sample_rate) {
     case RATE_50HZ: