.\" $NetBSD: btsco.4,v 1.13 2017/07/03 21:30:58 wiz Exp $
.\"
.\" Copyright (c) 2006 Itronix Inc.
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.\" Written by Iain Hibbert for Itronix Inc.
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.Dd November 29, 2014
.Dt BTSCO 4
.Os
.Sh NAME
.Nm btsco
.Nd Bluetooth SCO Audio
.Sh SYNOPSIS
.Cd "btsco*	at bthub?"
.Cd "audio*	at audiobus?"
.Sh DESCRIPTION
The
.Nm
driver provides support for Bluetooth SCO (Synchronous connection-oriented)
Audio devices through the
.Xr audio 4
driver.
.Pp
The
.Nm
driver must be configured at run time with the
.Xr btdevctl 8
program.
The following properties are used by the
.Nm
driver during autoconfiguration:
.Pp
.Bl -tag -width listenXX
.It local-bdaddr
Local device address.
.It remote-bdaddr
Remote device address.
.It service-name
The
.Nm
driver matches the
.Sq HF
and
.Sq HSET
services.
For the
.Sq HF
service, the
.Nm
device will, on
.Xr open 2 ,
listen for incoming connections from the remote device.
Otherwise,
.Nm
will attempt to initiate a connection to the remote device.
.It rfcomm-channel
This integer value is not used directly, but will be stored and
passed via the
.Dv BTSCO_INFO
ioctl as below:
.El
.Pp
SCO connections require a baseband connection between the two devices before
they can be created.
The
.Nm
driver does not create this, but can provide information to facilitate
an application setting up a control channel prior to use, via the
.Dv BTSCO_INFO
.Xr ioctl 2
call on the mixer device, which returns a
.Ar btsco_info
structure as follows:
.Bd -literal
#include <dev/bluetooth/btsco.h>

struct btsco_info {
	bdaddr_t	laddr;		/* controller bdaddr */
	bdaddr_t	raddr;		/* headset bdaddr */
	uint8_t		channel;	/* RFCOMM channel */
	int		vgs;		/* mixer index speaker */
	int		vgm;		/* mixer index mic */
};

#define BTSCO_INFO	_IOR('b', 16, struct btsco_info)
.Ed
.Pp
The
.Nm
driver can be configured to act in Connect or Listen mode.
In Connect mode, the
.Nm
driver will initiate a connection to the remote device on an
.Xr open 2
call, whereas in Listen mode,
.Xr open 2
will block until the remote device initiates the connection.
.Sh SEE ALSO
.Xr bthset 1 ,
.Xr ioctl 2 ,
.Xr audio 4 ,
.Xr bluetooth 4 ,
.Xr bthub 4 ,
.Xr btdevctl 8
.Sh HISTORY
The
.Nm
driver
was written for
.Nx 4.0
by
.An Iain Hibbert
under the sponsorship of Itronix, Inc.
.Sh BUGS
.Nm
takes no notice of the HCI Voice Setting in the Bluetooth controller, and this
must be 0x0060 (the default) as alternate values are currently unsupported.