[DO NOT MERGE] px4_i2c_device_external hacks

platforms/common/i2c.cpp

@@ -42,7 +42,17 @@ bool px4_i2c_bus_external(const px4_i2c_bus_t &bus)
 {
 	return bus.is_external;
 }
-#endif
+#endif // BOARD_OVERRIDE_I2C_BUS_EXTERNAL
+
+#ifndef BOARD_OVERRIDE_I2C_DEVICE_EXTERNAL
+#include <drivers/device/Device.hpp>
+bool px4_i2c_device_external(const uint32_t device_id)
+{
+	device::Device::DeviceId dev_id{};
+	dev_id.devid = device_id;
+	return px4_i2c_bus_external(dev_id.devid_s.bus);
+}
+#endif // BOARD_OVERRIDE_I2C_DEVICE_EXTERNAL
 
 bool I2CBusIterator::next()
 {

platforms/common/include/px4_platform_common/i2c.h

@@ -66,6 +66,11 @@ static inline bool px4_i2c_bus_external(int bus)
 	return true;
 }
 
+/**
+ * runtime-check if a board has a specific device as external.
+ * This can be overridden by a board to add run-time checks.
+ */
+__EXPORT bool px4_i2c_device_external(const uint32_t device_id);
 
 /**
  * @class I2CBusIterator