What we really want to do here is set a flag that the agent has not been
released yet. If this is the case we should send the Disconnect call on
disable.
It uses BlueZ through to get HFP working following the
org.bluez.HandsfreeGateway and org.bluez.HandsfreeAgent from
the BlueZ D-Bus API.
You need the HFP suport into BlueZ and the new D-Bus 1.3 or
later with fd-passing support.
Many thanks to Zhenhua Zhang <zhenhua.zhang@intel.com> for its
prototype on this code.
The call volume driver listens the speaker volume and microphone
gain from the AG. It also allow to synchronze the speaker and
microphone volume changes with the AG through AT+VGS and AT+VGM.
Volume level synchronization from HFP spec 1.5 Section 4.28.2
is performed on startup.
This driver handles phone informations about registration status, signal
strength and roaming status listening +CIEV commands. It also gets the
Network Operator name with +COPS commands.