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 *, 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 is V4L2_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.

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;
  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

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_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.

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.

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