1.21. 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_CUSTOM
Match will use the logic provided by
struct v4l2_async_subdev
.match opsV4L2_ASYNC_MATCH_DEVNAME
Match will use the device name
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 asyncrhronous 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;
const char *device_name;
struct {
int adapter_id;
unsigned short address;
} i2c;
struct {
bool (*match)(struct device *, struct v4l2_async_subdev *);
void *priv;
} custom;
} match;
struct list_head 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.device_name
string containing the device name to be matched. Used if match_type is
V4L2_ASYNC_MATCH_DEVNAME
.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
.match.custom
Driver-specific match criteria. Used if match_type is
V4L2_ASYNC_MATCH_CUSTOM
.match.custom.match
Driver-specific match function to be used if
V4L2_ASYNC_MATCH_CUSTOM
.match.custom.priv
Driver-specific private struct with match parameters to be used if
V4L2_ASYNC_MATCH_CUSTOM
.list
used to link struct v4l2_async_subdev objects, waiting to be probed, to a notifier->waiting 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);
};
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
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struct
v4l2_async_notifier
¶ v4l2_device notifier data
Definition
struct v4l2_async_notifier {
const struct v4l2_async_notifier_operations *ops;
unsigned int num_subdevs;
unsigned int max_subdevs;
struct v4l2_async_subdev **subdevs;
struct v4l2_device *v4l2_dev;
struct v4l2_subdev *sd;
struct v4l2_async_notifier *parent;
struct list_head waiting;
struct list_head done;
struct list_head list;
};
Members
ops
notifier operations
num_subdevs
number of subdevices used in the subdevs array
max_subdevs
number of subdevices allocated in the subdevs array
subdevs
array of pointers to subdevice descriptors
v4l2_dev
v4l2_device of the root notifier, NULL otherwise
sd
sub-device that registered the notifier, NULL otherwise
parent
parent notifier
waiting
list of struct v4l2_async_subdev, waiting for their drivers
done
list of struct v4l2_subdev, already probed
list
member in a global list of notifiers
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int
v4l2_async_notifier_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_notifier_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_notifier_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_notifier_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_notifier_parse_fwnode_endpoints or v4l2_fwnode_reference_parse_sensor_common.
There is no harm from calling v4l2_async_notifier_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_common
(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_notifier_parse_fwnode_sensor_common()
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