doc: Bluetooth: Add CAP documentation

Add documentation for CAP by adding the reference to the API
document.

Signed-off-by: Emil Gydesen <emil.gydesen@nordicsemi.no>

doc/connectivity/bluetooth/api/cap.rst

@@ -0,0 +1,10 @@
+.. _bluetooth_cap:
+
+Commmon Audio Profile
+#####################
+
+
+API Reference
+*************
+
+.. doxygengroup:: bt_cap

doc/connectivity/bluetooth/api/index.rst

@@ -9,6 +9,7 @@ Bluetooth APIs
    att.rst
    audio.rst
    bap.rst
+   cap.rst
    connection_mgmt.rst
    controller.rst
    coordinated_sets.rst
@@ -31,6 +32,7 @@ Bluetooth APIs
    shell/bap.rst
    shell/bap_broadcast_assistant.rst
    shell/bap_scan_delegator.rst
+   shell/cap.rst
    shell/ccp.rst
    shell/csip.rst
    shell/iso.rst

doc/connectivity/bluetooth/api/shell/cap.rst

@@ -0,0 +1,139 @@
+Bluetooth: Common Audio Profile Shell
+#####################################
+
+This document describes how to run the Common Audio Profile functionality.
+
+CAP Acceptor
+************
+
+The Acceptor will typically be a resource-constrained device, such as a headset, earbud or hearing
+aid. The Acceptor can initialize a Coordinated Set Identification Service instance, if it is in
+a pair with one or more other CAP Acceptors.
+
+Using the CAP Acceptor
+======================
+
+When the Bluetooth stack has been initialized (:code:`bt init`), the Acceptor can be registered by
+by calling :code:`cap_acceptor init`, which will register the CAS and CSIS services, as well as
+register callbacks.
+
+.. code-block:: console
+
+
+   cap_acceptor --help
+   cap_acceptor - Bluetooth CAP acceptor shell commands
+   Subcommands:
+     init          :Initialize the service and register callbacks [size <int>]
+                    [rank <int>] [not-lockable] [sirk <data>]
+     lock          :Lock the set
+     release       :Release the set [force]
+     print_sirk    :Print the currently used SIRK
+     set_sirk_rsp  :Set the response used in SIRK requests <accept, accept_enc,
+                    reject, oob>
+
+Besides initializing the CAS and the CSIS, there are also commands to lock and release the CSIS
+instance, as well as printing and modifying access to the SIRK of the CSIS.
+
+
+CAP Initiator
+*************
+
+The Initiator will typically be a resource-rich device, such as a phone or PC. The Initiator can
+discover CAP Acceptors's CAS and optional CSIS services. The CSIS service can be read to provide
+information about other CAP Acceptors in the same Coordinated Set. The Initiator can execute
+stream control procedures on sets of devices, either ad-hoc or Coordinated, and thus provides an
+easy way to setup multiple streams on multiple devices at once.
+
+Using the CAP Initiator
+=======================
+
+When the Bluetooth stack has been initialized (:code:`bt init`), the Initiator can discover CAS and
+the optionally included CSIS instance by calling (:code:`cap_initiator discover`).
+
+.. code-block:: console
+
+   cap_initiator --help
+   cap_initiator - Bluetooth CAP initiator shell commands
+   Subcommands:
+     discover        :Discover CAS
+     unicast-start   :Unicast Start [csip] [sinks <cnt> (default 1)] [sources <cnt>
+                      (default 1)] [conns (<cnt> | all) (default 1)]
+     unicast-list    :Unicast list streams
+     unicast-update  :Unicast Update <all | stream [stream [stream...]]>
+     unicast-stop    :Unicast stop all streams
+
+Before being able to perform any stream operation, the device must also perform the
+:code:`bap discover` operation to discover the ASEs and PAC records. The :code:`bap init`
+command also needs to be called.
+
+When connected
+--------------
+
+Discovering CAS and CSIS on a device:
+
+.. code-block:: console
+
+   uart:~$ cap_initiator discover
+   discovery completed with CSIS
+
+
+Discovering ASEs and PAC records on a device:
+
+.. code-block:: console
+
+   uart:~$ bap discover
+   conn 0x81cc260: #0: codec 0x81d5b28 dir 0x01
+   codec 0x06 cid 0x0000 vid 0x0000 count 5
+   data #0: type 0x01 len 2
+   00000000: f5                                               |.                |
+   data #1: type 0x02 len 1
+   data #2: type 0x03 len 1
+   data #3: type 0x04 len 4
+   00000000: 1e 00 f0                                         |...              |
+   data #4: type 0x05 len 1
+   meta #0: type 0x01 len 2
+   00000000: 06                                               |.                |
+   dir 1 loc 1
+   snk ctx 6 src ctx 6
+   Conn: 0x81cc260, Sink #0: ep 0x81e4248
+   Conn: 0x81cc260, Sink #1: ep 0x81e46a8
+   conn 0x81cc260: #0: codec 0x81d5f00 dir 0x02
+   codec 0x06 cid 0x0000 vid 0x0000 count 5
+   data #0: type 0x01 len 2
+   00000000: f5                                               |.                |
+   data #1: type 0x02 len 1
+   data #2: type 0x03 len 1
+   data #3: type 0x04 len 4
+   00000000: 1e 00 f0                                         |...              |
+   data #4: type 0x05 len 1
+   meta #0: type 0x01 len 2
+   00000000: 06                                               |.                |
+   dir 2 loc 1
+   snk ctx 6 src ctx 6
+   Conn: 0x81cc260, Source #0: ep 0x81e5c88
+   Conn: 0x81cc260, Source #1: ep 0x81e60e8
+   Discover complete: err 0
+
+Both of the above commands should be done for each device that you want to use in the set.
+To use multiple devices, simply connect to more and then use :code:`bt select` the device to execute
+the commands on.
+
+Once all devices have been connected and the respective discovery commands have been called, the
+:code:`cap_initiator unicast-start` command can be used to put one or more streams into the
+streaming state.
+
+.. code-block:: console
+
+   uart:~$ cap_initiator unicast-start sinks 1 sources 0 conns all
+   Setting up 1 sinks and 0 sources on each (2) conn
+   Starting 1 streams
+   Unicast start completed
+
+To stop all the streams that has been started, the :code:`cap_initiator unicast-stop` command can be
+used.
+
+
+.. code-block:: console
+
+   uart:~$ cap_initiator unicast-stop
+   Unicast stopped for group 0x81e41c0 completed

doc/connectivity/bluetooth/bluetooth-audio-arch.rst

@@ -43,10 +43,6 @@ GAF has been implemented in Zephyr with the following structure.
 
    Zephyr Generic Audio Framework
 
-Currently CAP (and CAS) as well as CCP (and TBS) are not yet implemented in
-Zephyr. Similarly the top-level profiles TMAP and HAP are also not yet
-implemented.
-
 Using the Bluetooth Audio Stack
 ===============================
 
@@ -63,6 +59,26 @@ rendering/capture control profiles, or vice versa. Using the higher layer
 profiles will however typically provide a better user experience and better
 interoperability with other devices.
 
+Common Audio Profile (CAP)
+--------------------------
+
+The Common Audio Profile introduces restrictions and requirements on the lower layer profiles.
+The procedures in CAP works on one or more streams for one or more devices. Is it thus possible via
+CAP to do a single function call to setup multiple streams across multiple devices.
+
+:numref:`bluetooth_audio_arch_cap_proc` shows a complete structure of the procedures in CAP and
+how they correspond to procedures from the other profiles. The circles with I, A and C show whether
+the procedure has active involvement or requirements from the CAP Initiator, CAP Accept and CAP
+Commander roles respectively.
+
+.. _bluetooth_audio_arch_cap_proc:
+.. figure:: img/cap_proc.svg
+   :align: center
+   :alt: Common Audio Profile Procedures
+
+   Common Audio Profile Procedures
+
+The API reference for CAP can be found in :ref:`Common Audio Profile <bluetooth_cap>`.
 
 Stream Control (BAP)
 --------------------