diff --git a/libraries/AP_HAL_Linux/SPIDriver.cpp b/libraries/AP_HAL_Linux/SPIDriver.cpp
index 7dc0694c8d..b2df5ac436 100644
--- a/libraries/AP_HAL_Linux/SPIDriver.cpp
+++ b/libraries/AP_HAL_Linux/SPIDriver.cpp
@@ -42,8 +42,8 @@ LinuxSPIDeviceDriver LinuxSPIDeviceManager::_device[0];
 #endif
 
 // have a separate semaphore per bus
-LinuxSemaphore LinuxSPIDeviceManager::_semaphore[LINUX_SPI_NUM_BUSES];
-int LinuxSPIDeviceManager::_fd[LINUX_SPI_NUM_BUSES];
+LinuxSemaphore LinuxSPIDeviceManager::_semaphore[LINUX_SPI_MAX_BUSES];
+int LinuxSPIDeviceManager::_fd[LINUX_SPI_MAX_BUSES];
 
 LinuxSPIDeviceDriver::LinuxSPIDeviceDriver(uint8_t bus, enum AP_HAL::SPIDevice type, uint8_t mode, uint8_t bitsPerWord, uint8_t cs_pin, uint32_t lowspeed, uint32_t highspeed):
     _bus(bus),
@@ -111,15 +111,23 @@ void LinuxSPIDeviceDriver::transfer(const uint8_t *data, uint16_t len)
 
 void LinuxSPIDeviceManager::init(void *)
 {
-    char path[] = "/dev/spidevN.0";
-    for (uint8_t i=0; i<LINUX_SPI_NUM_BUSES; i++) {
-        path[11] = '0' + i;
-        _fd[i] = open(path, O_RDWR);
-        if (_fd[i] == -1) {
-            hal.scheduler->panic("SPIDriver: unable to open SPI bus");
-        }
+    for (uint8_t i=0; i<LINUX_SPI_MAX_BUSES; i++) {
+        _fd[i] = -1;
     }
     for (uint8_t i=0; i<LINUX_SPI_DEVICE_NUM_DEVICES; i++) {
+        if (_device[i]._bus >= LINUX_SPI_MAX_BUSES) {
+            hal.scheduler->panic("SPIDriver: invalid bus number");
+        }
+        if (_fd[_device[i]._bus] == -1) {
+            char path[] = "/dev/spidevN.0";
+            path[11] = '0' + _device[i]._bus;
+            _fd[_device[i]._bus] = open(path, O_RDWR);            
+            if (_fd[_device[i]._bus] == -1) {
+                hal.scheduler->panic("SPIDriver: unable to open SPI bus");
+            }
+            printf("Opened %s\n", path);
+            fflush(stdout);
+        }
         _device[i].init();
     }
 }
diff --git a/libraries/AP_HAL_Linux/SPIDriver.h b/libraries/AP_HAL_Linux/SPIDriver.h
index afbb472d3a..144ebe60f7 100644
--- a/libraries/AP_HAL_Linux/SPIDriver.h
+++ b/libraries/AP_HAL_Linux/SPIDriver.h
@@ -6,16 +6,15 @@
 #include "Semaphores.h"
 
 #if CONFIG_HAL_BOARD_SUBTYPE == HAL_BOARD_SUBTYPE_LINUX_PXF || CONFIG_HAL_BOARD_SUBTYPE == HAL_BOARD_SUBTYPE_LINUX_ERLE
-#define LINUX_SPI_NUM_BUSES 2
 #define LINUX_SPI_DEVICE_NUM_DEVICES 6
 #elif CONFIG_HAL_BOARD_SUBTYPE == HAL_BOARD_SUBTYPE_LINUX_NAVIO
-#define LINUX_SPI_NUM_BUSES 1
 #define LINUX_SPI_DEVICE_NUM_DEVICES 1
 #else
-#define LINUX_SPI_NUM_BUSES 0
 #define LINUX_SPI_DEVICE_NUM_DEVICES 0
 #endif
 
+#define LINUX_SPI_MAX_BUSES 3
+
 class Linux::LinuxSPIDeviceDriver : public AP_HAL::SPIDeviceDriver {
 public:
     friend class Linux::LinuxSPIDeviceManager;
@@ -55,8 +54,8 @@ public:
 
 private:
     static LinuxSPIDeviceDriver _device[LINUX_SPI_DEVICE_NUM_DEVICES];
-    static LinuxSemaphore _semaphore[LINUX_SPI_NUM_BUSES];
-    static int _fd[LINUX_SPI_NUM_BUSES];
+    static LinuxSemaphore _semaphore[LINUX_SPI_MAX_BUSES];
+    static int _fd[LINUX_SPI_MAX_BUSES];
 };
 
 #endif // __AP_HAL_LINUX_SPIDRIVER_H__