diff --git a/automotive/audiocontrol/1.0/default/AudioControl.cpp b/automotive/audiocontrol/1.0/default/AudioControl.cpp
index b40f2ae..c96580e 100644
--- a/automotive/audiocontrol/1.0/default/AudioControl.cpp
+++ b/automotive/audiocontrol/1.0/default/AudioControl.cpp
@@ -36,7 +36,8 @@
 };
 
 
-Return<int32_t> AudioControl::getBusForContext(uint32_t contextNumber) {
+Return<int32_t> AudioControl::getBusForContext(ContextNumber ctxt) {
+    unsigned contextNumber = static_cast<unsigned>(ctxt);
     if (contextNumber > sContextNumberMax) {
         ALOGE("Unexpected context number %d (max expected is %d)", contextNumber, sContextCount);
         return -1;
diff --git a/automotive/audiocontrol/1.0/default/AudioControl.h b/automotive/audiocontrol/1.0/default/AudioControl.h
index 89e41f9..37f43c6 100644
--- a/automotive/audiocontrol/1.0/default/AudioControl.h
+++ b/automotive/audiocontrol/1.0/default/AudioControl.h
@@ -23,7 +23,7 @@
 struct AudioControl : public IAudioControl {
 public:
     // Methods from ::android::hardware::automotive::audiocontrol::V1_0::IAudioControl follow.
-    Return<int32_t> getBusForContext(uint32_t contextNumber) override;
+    Return<int32_t> getBusForContext(ContextNumber contextNumber) override;
     Return<void> setBalanceTowardRight(float value) override;
     Return<void> setFadeTowardFront(float value) override;