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media: v4l: async: Rename v4l2_async_subdev as v4l2_async_connection

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Rename v4l2_async_subdev as v4l2_async_connection, in order to
differentiate between the sub-devices and their connections: one
sub-device can have many connections but the V4L2 async framework has so
far allowed just a single one. Connections in this context will later
translate into either MC ancillary or data links.

This patch prepares changing that relation by changing existing users of
v4l2_async_subdev to switch to v4l2_async_connection. Async sub-devices
themselves will not be needed anymore

Additionally, __v4l2_async_nf_add_subdev() has been renamed
__v4l2_async_nf_add_connection().

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Tested-by: Philipp Zabel <p.zabel@pengutronix.de> # imx6qp
Tested-by: Niklas Söderlund <niklas.soderlund@ragnatech.se> # rcar + adv746x
Tested-by: Aishwarya Kothari <aishwarya.kothari@toradex.com> # Apalis i.MX6Q with TC358743
Tested-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com> # Renesas RZ/G2L SMARC
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
This commit is contained in:
Sakari Ailus
2023-02-16 14:54:53 +01:00
committed by Mauro Carvalho Chehab
parent 1029939b37
commit adb2dcd5f2
70 changed files with 368 additions and 361 deletions
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Documentation/driver-api/media/v4l2-subdev.rst
+29 -22
View File
@@ -206,60 +206,67 @@ of an unregister notifier, it must be cleaned up by calling
Before registering the notifier, bridge drivers must do two things: first, the
notifier must be initialized using the :c:func:`v4l2_async_nf_init`. Second,
bridge drivers can then begin to form a list of subdevice descriptors that the
bridge device needs for its operation. :c:func:`v4l2_async_nf_add_fwnode`,
bridge drivers can then begin to form a list of async connection descriptors
that the bridge device needs for its
operation. :c:func:`v4l2_async_nf_add_fwnode`,
:c:func:`v4l2_async_nf_add_fwnode_remote` and :c:func:`v4l2_async_nf_add_i2c`
are available for that purpose.
Async connection descriptors describe connections to external sub-devices the
drivers for which are not yet probed. Based on an async connection, a media data
or ancillary link may be created when the related sub-device becomes
available. There may be one or more async connections to a given sub-device but
this is not known at the time of adding the connections to the notifier. Async
connections are bound as matching async sub-devices are found, one by one.
Asynchronous sub-device registration helper for camera sensor drivers
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
:c:func:`v4l2_async_register_subdev_sensor` is a helper function for sensor
drivers registering their own async sub-device, but it also registers a notifier
and further registers async sub-devices for lens and flash devices found in
drivers registering their own async connection, but it also registers a notifier
and further registers async connections for lens and flash devices found in
firmware. The notifier for the sub-device is unregistered and cleaned up with
the async sub-device, using :c:func:`v4l2_async_unregister_subdev`.
Asynchronous sub-device notifier example
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
These functions allocate an async sub-device descriptor which is of type struct
:c:type:`v4l2_async_subdev` embedded in a driver-specific struct. The &struct
:c:type:`v4l2_async_subdev` shall be the first member of this struct:
These functions allocate an async connection descriptor which is of type struct
:c:type:`v4l2_async_connection` embedded in a driver-specific struct. The &struct
:c:type:`v4l2_async_connection` shall be the first member of this struct:
.. code-block:: c
struct my_async_subdev {
struct v4l2_async_subdev asd;
struct my_async_connection {
struct v4l2_async_connection asc;
...
};
struct my_async_subdev *my_asd;
struct my_async_connection *my_asc;
struct fwnode_handle *ep;
...
my_asd = v4l2_async_nf_add_fwnode_remote(&notifier, ep,
struct my_async_subdev);
my_asc = v4l2_async_nf_add_fwnode_remote(&notifier, ep,
struct my_async_connection);
fwnode_handle_put(ep);
if (IS_ERR(my_asd))
return PTR_ERR(my_asd);
if (IS_ERR(my_asc))
return PTR_ERR(my_asc);
Asynchronous sub-device notifier callbacks
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
The V4L2 core will then use these descriptors to match asynchronously
registered subdevices to them. If a match is detected the ``.bound()``
notifier callback is called. After all subdevices have been located the
.complete() callback is called. When a subdevice is removed from the
system the .unbind() method is called. All three callbacks are optional.
The V4L2 core will then use these connection descriptors to match asynchronously
registered subdevices to them. If a match is detected the ``.bound()`` notifier
callback is called. After all connections have been bound the .complete()
callback is called. When a connection is removed from the system the
``.unbind()`` method is called. All three callbacks are optional.
Drivers can store any type of custom data in their driver-specific
:c:type:`v4l2_async_subdev` wrapper. If any of that data requires special
:c:type:`v4l2_async_connection` wrapper. If any of that data requires special
handling when the structure is freed, drivers must implement the ``.destroy()``
notifier callback. The framework will call it right before freeing the
:c:type:`v4l2_async_subdev`.
:c:type:`v4l2_async_connection`.
Calling subdev operations
~~~~~~~~~~~~~~~~~~~~~~~~~