2.22. V4L2 async kAPI¶
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enum v4l2_async_match_type¶
type of asynchronous subdevice logic to be used in order to identify a match
Constants
V4L2_ASYNC_MATCH_TYPE_I2C
Match will check for I2C adapter ID and address
V4L2_ASYNC_MATCH_TYPE_FWNODE
Match will use firmware node
Description
This enum is used by the asynchronous connection logic to define the algorithm that will be used to match an asynchronous device.
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struct v4l2_async_match_desc¶
async connection match information
Definition:
struct v4l2_async_match_desc {
enum v4l2_async_match_type type;
union {
struct fwnode_handle *fwnode;
struct {
int adapter_id;
unsigned short address;
} i2c;
};
};
Members
type
type of match that will be used
{unnamed_union}
anonymous
fwnode
pointer to
struct fwnode_handle
to be matched. Used if match_type isV4L2_ASYNC_MATCH_TYPE_FWNODE
.i2c
embedded struct with I2C parameters to be matched. Both match.i2c.adapter_id and match.i2c.address should be matched. Used if match_type is
V4L2_ASYNC_MATCH_TYPE_I2C
.
i2c.adapter_id
I2C adapter ID to be matched. Used if match_type is
V4L2_ASYNC_MATCH_TYPE_I2C
.
i2c.address
I2C address to be matched. Used if match_type is
V4L2_ASYNC_MATCH_TYPE_I2C
.
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struct v4l2_async_connection¶
sub-device connection descriptor, as known to a bridge
Definition:
struct v4l2_async_connection {
struct v4l2_async_match_desc match;
struct v4l2_async_notifier *notifier;
struct list_head asc_entry;
struct list_head asc_subdev_entry;
struct v4l2_subdev *sd;
};
Members
match
struct of match type and per-bus type matching data sets
notifier
the async notifier the connection is related to
asc_entry
used to add
struct v4l2_async_connection
objects to the notifier waiting_list or done_listasc_subdev_entry
entry in struct v4l2_async_subdev.asc_list list
sd
the related sub-device
Description
When this struct is used as a member in a driver specific struct, the driver
specific struct shall contain the struct v4l2_async_connection
as its first
member.
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struct v4l2_async_notifier_operations¶
Asynchronous V4L2 notifier operations
Definition:
struct v4l2_async_notifier_operations {
int (*bound)(struct v4l2_async_notifier *notifier,struct v4l2_subdev *subdev, struct v4l2_async_connection *asc);
int (*complete)(struct v4l2_async_notifier *notifier);
void (*unbind)(struct v4l2_async_notifier *notifier,struct v4l2_subdev *subdev, struct v4l2_async_connection *asc);
void (*destroy)(struct v4l2_async_connection *asc);
};
Members
bound
a sub-device has been bound by the given connection
complete
All connections have been bound successfully. The complete callback is only executed for the root notifier.
unbind
a subdevice is leaving
destroy
the asc is about to be freed
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struct v4l2_async_notifier¶
v4l2_device notifier data
Definition:
struct v4l2_async_notifier {
const struct v4l2_async_notifier_operations *ops;
struct v4l2_device *v4l2_dev;
struct v4l2_subdev *sd;
struct v4l2_async_notifier *parent;
struct list_head waiting_list;
struct list_head done_list;
struct list_head notifier_entry;
};
Members
ops
notifier operations
v4l2_dev
v4l2_device of the root notifier, NULL otherwise
sd
sub-device that registered the notifier, NULL otherwise
parent
parent notifier
waiting_list
list of
struct v4l2_async_connection
, waiting for their driversdone_list
list of
struct v4l2_subdev
, already probednotifier_entry
member in a global list of notifiers
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struct v4l2_async_subdev_endpoint¶
Entry in sub-device's fwnode list
Definition:
struct v4l2_async_subdev_endpoint {
struct list_head async_subdev_endpoint_entry;
struct fwnode_handle *endpoint;
};
Members
async_subdev_endpoint_entry
An entry in async_subdev_endpoint_list of
struct v4l2_subdev
endpoint
Endpoint fwnode agains which to match the sub-device
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void v4l2_async_debug_init(struct dentry *debugfs_dir)¶
Initialize debugging tools.
Parameters
struct dentry *debugfs_dir
pointer to the parent debugfs
struct dentry
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void v4l2_async_nf_init(struct v4l2_async_notifier *notifier, struct v4l2_device *v4l2_dev)¶
Initialize a notifier.
Parameters
struct v4l2_async_notifier *notifier
pointer to
struct v4l2_async_notifier
struct v4l2_device *v4l2_dev
pointer to
struct v4l2_device
Description
This function initializes the notifier asc_entry. It must be called
before adding a subdevice to a notifier, using one of:
v4l2_async_nf_add_fwnode_remote()
,
v4l2_async_nf_add_fwnode()
or
v4l2_async_nf_add_i2c()
.
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void v4l2_async_subdev_nf_init(struct v4l2_async_notifier *notifier, struct v4l2_subdev *sd)¶
Initialize a sub-device notifier.
Parameters
struct v4l2_async_notifier *notifier
pointer to
struct v4l2_async_notifier
struct v4l2_subdev *sd
pointer to
struct v4l2_subdev
Description
This function initializes the notifier asc_list. It must be called
before adding a subdevice to a notifier, using one of:
v4l2_async_nf_add_fwnode_remote()
, v4l2_async_nf_add_fwnode()
or
v4l2_async_nf_add_i2c()
.
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v4l2_async_nf_add_fwnode¶
v4l2_async_nf_add_fwnode (notifier, fwnode, type)
Allocate and add a fwnode async subdev to the notifier's master asc_list.
Parameters
notifier
pointer to
struct v4l2_async_notifier
fwnode
fwnode handle of the sub-device to be matched, pointer to
struct fwnode_handle
type
Type of the driver's async sub-device or connection struct. The
struct v4l2_async_connection
shall be the first member of the driver's async struct, i.e. both begin at the same memory address.
Description
Allocate a fwnode-matched asc of size asc_struct_size, and add it to the notifiers asc_list. The function also gets a reference of the fwnode which is released later at notifier cleanup time.
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v4l2_async_nf_add_fwnode_remote¶
v4l2_async_nf_add_fwnode_remote (notifier, ep, type)
Allocate and add a fwnode remote async subdev to the notifier's master asc_list.
Parameters
notifier
pointer to
struct v4l2_async_notifier
ep
local endpoint pointing to the remote connection to be matched, pointer to
struct fwnode_handle
type
Type of the driver's async connection struct. The
struct v4l2_async_connection
shall be the first member of the driver's async connection struct, i.e. both begin at the same memory address.
Description
Gets the remote endpoint of a given local endpoint, set it up for fwnode matching and adds the async connection to the notifier's asc_list. The function also gets a reference of the fwnode which is released later at notifier cleanup time.
This is just like v4l2_async_nf_add_fwnode()
, but with the
exception that the fwnode refers to a local endpoint, not the remote one.
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v4l2_async_nf_add_i2c¶
v4l2_async_nf_add_i2c (notifier, adapter, address, type)
Allocate and add an i2c async subdev to the notifier's master asc_list.
Parameters
notifier
pointer to
struct v4l2_async_notifier
adapter
I2C adapter ID to be matched
address
I2C address of connection to be matched
type
Type of the driver's async connection struct. The
struct v4l2_async_connection
shall be the first member of the driver's async connection struct, i.e. both begin at the same memory address.
Description
Same as v4l2_async_nf_add_fwnode()
but for I2C matched
connections.
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int v4l2_async_subdev_endpoint_add(struct v4l2_subdev *sd, struct fwnode_handle *fwnode)¶
Add an endpoint fwnode to async sub-device matching list
Parameters
struct v4l2_subdev *sd
the sub-device
struct fwnode_handle *fwnode
the endpoint fwnode to match
Description
Add a fwnode to the async sub-device's matching list. This allows registering multiple async sub-devices from a single device.
Note that calling v4l2_subdev_cleanup()
as part of the sub-device's cleanup
if endpoints have been added to the sub-device's fwnode matching list.
Returns an error on failure, 0 on success.
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struct v4l2_async_connection *v4l2_async_connection_unique(struct v4l2_subdev *sd)¶
return a unique
struct v4l2_async_connection
for a sub-device
Parameters
struct v4l2_subdev *sd
the sub-device
Description
Return an async connection for a sub-device, when there is a single one only.
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int v4l2_async_nf_register(struct v4l2_async_notifier *notifier)¶
registers a subdevice asynchronous notifier
Parameters
struct v4l2_async_notifier *notifier
pointer to
struct v4l2_async_notifier
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void v4l2_async_nf_unregister(struct v4l2_async_notifier *notifier)¶
unregisters a subdevice asynchronous notifier
Parameters
struct v4l2_async_notifier *notifier
pointer to
struct v4l2_async_notifier
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void v4l2_async_nf_cleanup(struct v4l2_async_notifier *notifier)¶
clean up notifier resources
Parameters
struct v4l2_async_notifier *notifier
the notifier the resources of which are to be cleaned up
Description
Release memory resources related to a notifier, including the async
connections allocated for the purposes of the notifier but not the notifier
itself. The user is responsible for calling this function to clean up the
notifier after calling v4l2_async_nf_add_fwnode_remote()
,
v4l2_async_nf_add_fwnode()
or v4l2_async_nf_add_i2c()
.
There is no harm from calling v4l2_async_nf_cleanup()
in other
cases as long as its memory has been zeroed after it has been
allocated.
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int v4l2_async_register_subdev(struct v4l2_subdev *sd)¶
registers a sub-device to the asynchronous subdevice framework
Parameters
struct v4l2_subdev *sd
pointer to
struct v4l2_subdev
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int v4l2_async_register_subdev_sensor(struct v4l2_subdev *sd)¶
registers a sensor sub-device to the asynchronous sub-device framework and parse set up common sensor related devices
Parameters
struct v4l2_subdev *sd
pointer to struct
v4l2_subdev
Description
This function is just like v4l2_async_register_subdev()
with the exception
that calling it will also parse firmware interfaces for remote references
using v4l2_async_nf_parse_fwnode_sensor() and registers the
async sub-devices. The sub-device is similarly unregistered by calling
v4l2_async_unregister_subdev()
.
While registered, the subdev module is marked as in-use.
An error is returned if the module is no longer loaded on any attempts to register it.
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void v4l2_async_unregister_subdev(struct v4l2_subdev *sd)¶
unregisters a sub-device to the asynchronous subdevice framework
Parameters
struct v4l2_subdev *sd
pointer to
struct v4l2_subdev