Parse the gain changed AT commands from the headset and fire 2 new hooks as a result. The device will connect to those hooks and change the source/sink volumes.
When the source/sink volume changes, set the gain on the microphone or speaker respectively. Make sure we do nothing if the transport can not handle the gain changes.
34a5c75 backend-native: implement volume control
src/modules/bluetooth/backend-native.c | 55 +++++++++-
src/modules/bluetooth/bluez5-util.h | 9 ++
src/modules/bluetooth/module-bluez5-device.c | 140 ++++++++++++++++++++++++++
3 files changed, 203 insertions(+), 1 deletion(-)