From bfd03ab40cdc807c6bd3215078d9a0c22d1eab5d Mon Sep 17 00:00:00 2001
From: Pat Hickey <pat@galois.com>
Date: Wed, 5 Dec 2012 18:22:03 -0800
Subject: [PATCH] AP_Baro: robust spi device

---
 libraries/AP_Baro/AP_Baro_MS5611.cpp | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/libraries/AP_Baro/AP_Baro_MS5611.cpp b/libraries/AP_Baro/AP_Baro_MS5611.cpp
index 69038f97b9..ef94728a45 100644
--- a/libraries/AP_Baro/AP_Baro_MS5611.cpp
+++ b/libraries/AP_Baro/AP_Baro_MS5611.cpp
@@ -112,10 +112,16 @@ void AP_Baro_MS5611::_spi_write(uint8_t reg)
 // SPI should be initialized externally
 bool AP_Baro_MS5611::init()
 {
-    hal.scheduler->suspend_timer_procs();
     _spi = hal.spi->device(AP_HAL::SPIDevice_MS5611);
+    if (_spi == NULL) {
+        hal.console->println_P(PSTR("PANIC: AP_Baro_MS5611 could not get "
+                    "valid SPI device driver!"));
+        return false;
+    }
     _spi_sem = _spi->get_semaphore();
 
+    hal.scheduler->suspend_timer_procs();
+
     _spi_write(CMD_MS5611_RESET);
     hal.scheduler->delay(4);