1.21. V4L2 async kAPI¶
-
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 ops V4L2_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.
-
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 *dev, struct v4l2_async_subdev *sd);
void *priv;
} custom;
} 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.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
asd_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);
};
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
-
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 drivers
done
- list of struct v4l2_subdev, already probed
list
- member in a global list of notifiers
-
void
v4l2_async_notifier_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 the first call to v4l2_async_notifier_add_subdev.
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int
v4l2_async_notifier_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
Call this function before registering a notifier to link the provided asd to the notifiers master asd_list.
-
struct v4l2_async_subdev *
v4l2_async_notifier_add_fwnode_subdev
(struct v4l2_async_notifier * notifier, struct fwnode_handle * fwnode, unsigned int asd_struct_size)¶ Allocate and add a fwnode async subdev to the notifier's master asd_list.
Parameters
struct v4l2_async_notifier * notifier
- pointer to
struct v4l2_async_notifier
struct fwnode_handle * fwnode
- fwnode handle of the sub-device to be matched
unsigned int asd_struct_size
- size of the driver's async sub-device struct, including
sizeof(struct v4l2_async_subdev). 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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int
v4l2_async_notifier_add_fwnode_remote_subdev
(struct v4l2_async_notifier * notif, struct fwnode_handle * endpoint, struct v4l2_async_subdev * asd)¶ Allocate and add a fwnode remote async subdev to the notifier's master asd_list.
Parameters
struct v4l2_async_notifier * notif
- pointer to
struct v4l2_async_notifier
struct fwnode_handle * endpoint
- local endpoint pointing to the remote sub-device to be matched
struct v4l2_async_subdev * asd
- Async sub-device struct allocated by the caller. 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_notifier_add_fwnode_subdev, but with the exception that the fwnode refers to a local endpoint, not the remote one, and the function relies on the caller to allocate the async sub-device struct.
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struct v4l2_async_subdev *
v4l2_async_notifier_add_i2c_subdev
(struct v4l2_async_notifier * notifier, int adapter_id, unsigned short address, unsigned int asd_struct_size)¶ Allocate and add an i2c async subdev to the notifier's master asd_list.
Parameters
struct v4l2_async_notifier * notifier
- pointer to
struct v4l2_async_notifier
int adapter_id
- I2C adapter ID to be matched
unsigned short address
- I2C address of sub-device to be matched
unsigned int asd_struct_size
- size of the driver's async sub-device struct, including
sizeof(struct v4l2_async_subdev). 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 above but for I2C matched sub-devices.
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struct v4l2_async_subdev *
v4l2_async_notifier_add_devname_subdev
(struct v4l2_async_notifier * notifier, const char * device_name, unsigned int asd_struct_size)¶ Allocate and add a device-name async subdev to the notifier's master asd_list.
Parameters
struct v4l2_async_notifier * notifier
- pointer to
struct v4l2_async_notifier
const char * device_name
- device name string to be matched
unsigned int asd_struct_size
- size of the driver's async sub-device struct, including
sizeof(struct v4l2_async_subdev). 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 above but for device-name matched sub-devices.
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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
-
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
-
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
-
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_add_subdev, 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
-
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