Finalize C <=> C++ interface

src/avclan/hal/media.h

@@ -0,0 +1,32 @@
+// Copyright (C) 2026 Allen Hill <allenofthehills@gmail.com>
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+// Media-control HAL: emulate head-unit button presses to the audio source. This
+// is device functionality (see CDChanger), so this contract is consumed only by
+// the device implementation, not the app.
+
+#pragma once
+
+#include "avclan.h"
+
+#ifdef __cplusplus
+using MediaAction = avclan::MediaAction;
+extern "C" {
+#else
+typedef enum MediaAction MediaAction;
+#endif
+
+// One-time hardware bring-up for the media driver.
+void media_init(void);
+
+// Emulate a media function (button press) on the source device.
+void media_action(MediaAction fn);
+
+#ifndef NDEBUG
+bool media_mic_toggle(void);
+bool media_busy(void);
+#endif
+
+#ifdef __cplusplus
+}
+#endif