2.23. 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_I2C
Match will check for I2C adapter ID and address
V4L2_ASYNC_MATCH_FWNODE
Match will use firmware node
Description
This enum is used by the asynchronous sub-device logic to define the algorithm that will be used to match an asynchronous device.
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struct v4l2_async_subdev¶
sub-device descriptor, as known to a bridge
Definition:
struct v4l2_async_subdev {
enum v4l2_async_match_type match_type;
union {
struct fwnode_handle *fwnode;
struct {
int adapter_id;
unsigned short address;
} i2c;
} match;
struct list_head list;
struct list_head asd_list;
};
Members
match_type
type of match that will be used
match
union of per-bus type matching data sets
match.fwnode
pointer to
struct fwnode_handle
to be matched. Used if match_type isV4L2_ASYNC_MATCH_FWNODE
.
match.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_I2C
.
match.i2c.adapter_id
I2C adapter ID to be matched. Used if match_type is
V4L2_ASYNC_MATCH_I2C
.
match.i2c.address
I2C address to be matched. Used if match_type is
V4L2_ASYNC_MATCH_I2C
.
list
used to link
struct v4l2_async_subdev
objects, waiting to be probed, to a notifier->waiting listasd_list
used to add
struct v4l2_async_subdev
objects to the master notifier asd_list
Description
When this struct is used as a member in a driver specific struct,
the driver specific struct shall contain the struct
v4l2_async_subdev
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_subdev *asd);
int (*complete)(struct v4l2_async_notifier *notifier);
void (*unbind)(struct v4l2_async_notifier *notifier,struct v4l2_subdev *subdev, struct v4l2_async_subdev *asd);
void (*destroy)(struct v4l2_async_subdev *asd);
};
Members
bound
a subdevice driver has successfully probed one of the subdevices
complete
All subdevices have been probed successfully. The complete callback is only executed for the root notifier.
unbind
a subdevice is leaving
destroy
the asd 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 asd_list;
struct list_head waiting;
struct list_head done;
struct list_head list;
};
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
asd_list
master list of
struct v4l2_async_subdev
waiting
list of
struct v4l2_async_subdev
, waiting for their driversdone
list of
struct v4l2_subdev
, already probedlist
member in a global list of notifiers
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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)¶
Initialize a notifier.
Parameters
struct v4l2_async_notifier *notifier
pointer to
struct v4l2_async_notifier
Description
This function initializes the notifier asd_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()
,
v4l2_async_nf_add_i2c()
,
__v4l2_async_nf_add_subdev()
or
v4l2_async_nf_parse_fwnode_endpoints()
.
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int __v4l2_async_nf_add_subdev(struct v4l2_async_notifier *notifier, struct v4l2_async_subdev *asd)¶
Add an async subdev to the notifier's master asd list.
Parameters
struct v4l2_async_notifier *notifier
pointer to
struct v4l2_async_notifier
struct v4l2_async_subdev *asd
pointer to
struct v4l2_async_subdev
Description
warning: Drivers should avoid using this function and instead use one of:
v4l2_async_nf_add_fwnode()
,
v4l2_async_nf_add_fwnode_remote()
or
v4l2_async_nf_add_i2c()
.
Call this function before registering a notifier to link the provided asd to the notifiers master asd_list. The asd must be allocated with k*alloc() as it will be freed by the framework when the notifier is destroyed.
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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 asd_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 struct. The
struct v4l2_async_subdev
shall be the first member of the driver's async sub-device struct, i.e. both begin at the same memory address.
Description
Allocate a fwnode-matched asd of size asd_struct_size, and add it to the notifiers asd_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 asd_list.
Parameters
notifier
pointer to
struct v4l2_async_notifier
ep
local endpoint pointing to the remote sub-device to be matched, pointer to
struct fwnode_handle
type
Type of the driver's async sub-device struct. The
struct v4l2_async_subdev
shall be the first member of the driver's async sub-device 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 sub-device to the notifier's asd_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 asd_list.
Parameters
notifier
pointer to
struct v4l2_async_notifier
adapter
I2C adapter ID to be matched
address
I2C address of sub-device to be matched
type
Type of the driver's async sub-device struct. The
struct v4l2_async_subdev
shall be the first member of the driver's async sub-device struct, i.e. both begin at the same memory address.
Description
Same as v4l2_async_nf_add_fwnode()
but for I2C matched
sub-devices.
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int v4l2_async_nf_register(struct v4l2_device *v4l2_dev, struct v4l2_async_notifier *notifier)¶
registers a subdevice asynchronous notifier
Parameters
struct v4l2_device *v4l2_dev
pointer to
struct v4l2_device
struct v4l2_async_notifier *notifier
pointer to
struct v4l2_async_notifier
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int v4l2_async_subdev_nf_register(struct v4l2_subdev *sd, struct v4l2_async_notifier *notifier)¶
registers a subdevice asynchronous notifier for a sub-device
Parameters
struct v4l2_subdev *sd
pointer to
struct v4l2_subdev
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
sub-devices 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()
,
v4l2_async_nf_add_i2c()
,
__v4l2_async_nf_add_subdev()
or
v4l2_async_nf_parse_fwnode_endpoints()
.
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