added debug output to read of I2cComIf

linux/i2c/I2cComIF.cpp

@@ -146,10 +146,16 @@ ReturnValue_t I2cComIF::requestReceiveMessage(CookieIF *cookie,
 
     uint8_t* replyBuffer = i2cDeviceMapIter->second.replyBuffer.data();
 
-    if (read(fd, replyBuffer, requestLen) != static_cast<int>(requestLen)) {
+    int readLen = read(fd, replyBuffer, requestLen);
+
+    if (readLen != static_cast<int>(requestLen)) {
+#if FSFW_VERBOSE_LEVEL >= 1 and FSFW_CPP_OSTREAM_ENABLED == 1
         sif::error << "I2cComIF::requestReceiveMessage: Reading from I2C "
                 << "device failed with error code " << errno <<". Description"
                 << " of error: " << strerror(errno) << std::endl;
+        sif::error << "I2cComIF::requestReceiveMessage: Read only " << readLen << " from "
+                << requestLen << " bytes" << std::endl;
+#endif
         i2cDeviceMapIter->second.replyLen = 0;
         return HasReturnvaluesIF::RETURN_FAILED;
     }

linux/i2c/I2cComIF.h

@@ -12,6 +12,8 @@
  * @brief 	This is the communication interface for i2c devices connected
  * 			to a system running a linux OS.
  *
+ * @note    The xilinx linux kernel does not support to read more than 255 bytes at once.
+ *
  * @author 	J. Meier
  */
 class I2cComIF: public DeviceCommunicationIF, public SystemObject {