diff --git a/include/libcamera/transform.h b/include/libcamera/transform.h
index 4998a6c04cb7..44cb4c6fc974 100644
--- a/include/libcamera/transform.h
+++ b/include/libcamera/transform.h
@@ -71,7 +71,6 @@ constexpr Transform operator~(Transform t)
 }
 
 Transform transformFromRotation(int angle, bool *success = nullptr);
-Transform transformFromOrientation(const Orientation &orientation);
 
 Transform operator/(const Orientation &o1, const Orientation &o2);
 Orientation operator*(const Orientation &o, const Transform &t);
diff --git a/src/libcamera/transform.cpp b/src/libcamera/transform.cpp
index cd2717c28c3a..fb2d55ac1931 100644
--- a/src/libcamera/transform.cpp
+++ b/src/libcamera/transform.cpp
@@ -301,6 +301,8 @@ Transform transformFromRotation(int angle, bool *success)
 	return Transform::Identity;
 }
 
+namespace {
+
 /**
  * \brief Return the transform representing \a orientation
  * \param[in] orientation The orientation to convert
@@ -330,6 +332,8 @@ Transform transformFromOrientation(const Orientation &orientation)
 	return Transform::Identity;
 }
 
+} /* namespace */
+
 /**
  * \brief Return the Transform that applied to \a o2 gives \a o1
  * \param o1 The Orientation to obtain