mpu9150: option to disable I2C bypass setting

The existing hardcoded logic enables i2c bypass mode for AK8975.
This can cause the accelerometer to disappear on I2C bus. We add
a new member as a switch that can be used to disable bypass.

Change-Id: I2c61f4910d46ffb5940bb3c14b58bc65984fd12e
Signed-off-by: Jianxun Zhang <jianxun.zhang@intel.com>
Signed-off-by: Mihai Tudor Panu <mihai.tudor.panu@intel.com>

2 files changed, 27 insertions, 19 deletions

diff --git a/src/mpu9150/mpu9150.cxx b/src/mpu9150/mpu9150.cxx
index a4463a9..a253e84 100644
--- a/src/mpu9150/mpu9150.cxx
+++ b/src/mpu9150/mpu9150.cxx
@@ -31,11 +31,12 @@
 using namespace upm;
 using namespace std;
 
-MPU9150::MPU9150 (int bus, int address, int magAddress) :
+MPU9150::MPU9150 (int bus, int address, int magAddress, bool enableAk8975) :
   m_mag(0), MPU60X0(bus, address)
 {
   m_magAddress = magAddress;
   m_i2cBus = bus;
+  m_enableAk8975 = enableAk8975;
 }
 
 MPU9150::~MPU9150()
@@ -54,26 +55,30 @@ bool MPU9150::init()
       return false;
     }
 
-  // Now, we need to enable I2C bypass on the MPU60X0 component.  This
-  // will allow us to access the AK8975 Magnetometer on I2C addr 0x0c.
-  if (!enableI2CBypass(true))
+  // Enabling I2C bypass will allow us to access the
+  // AK8975 Magnetometer on I2C addr 0x0c.
+  if (m_enableAk8975 == true)
     {
-      throw std::runtime_error(std::string(__FUNCTION__) +
-                               ": Unable to enable I2C bypass");
-      return false;
-    }
+      if (!enableI2CBypass(true))
+        {
+          throw std::runtime_error(std::string(__FUNCTION__) +
+                                   ": Unable to enable I2C bypass");
+          return false;
+        }
 
-  // Now that we've done that, create an AK8975 instance and
-  // initialize it.
-  m_mag = new AK8975(m_i2cBus, m_magAddress);
+      // Now that we've done that, create an AK8975 instance and
+      // initialize it.
 
-  if (!m_mag->init())
-    {
-      throw std::runtime_error(std::string(__FUNCTION__) +
-                               ": Unable to init magnetometer");
-      delete m_mag;
-      m_mag = 0;
-      return false;
+      m_mag = new AK8975(m_i2cBus, m_magAddress);
+
+      if (!m_mag->init())
+        {
+          throw std::runtime_error(std::string(__FUNCTION__) +
+                                 ": Unable to init magnetometer");
+          delete m_mag;
+          m_mag = 0;
+          return false;
+        }
     }
 
   return true;
diff --git a/src/mpu9150/mpu9150.h b/src/mpu9150/mpu9150.h
index 32a6944..6567962 100644
--- a/src/mpu9150/mpu9150.h
+++ b/src/mpu9150/mpu9150.h
@@ -66,9 +66,11 @@ namespace upm {
      * @param bus I2C bus to use
      * @param address The address for this device
      * @param magAddress The address of the connected magnetometer
+     * @param enableAk8975 Enables i2c bypass mode for magnetometer, default
+     * is true
      */
     MPU9150 (int bus=MPU9150_I2C_BUS, int address=MPU9150_DEFAULT_I2C_ADDR,
-             int magAddress=AK8975_DEFAULT_I2C_ADDR);
+             int magAddress=AK8975_DEFAULT_I2C_ADDR, bool enableAk8975=true);
 
     /**
      * MPU9150 destructor
@@ -126,6 +128,7 @@ namespace upm {
   private:
     int m_i2cBus;
     uint8_t m_magAddress;
+    bool m_enableAk8975;
   };
 
 }