SYNOPSIS

struct media_device {
struct device * dev;
struct media_devnode devnode;
char model[32];
char driver_name[32];
char serial[40];
char bus_info[32];
u32 hw_revision;
u32 driver_version;
u64 topology_version;
u32 id;
struct ida entity_internal_idx;
int entity_internal_idx_max;
struct list_head entities;
struct list_head interfaces;
struct list_head pads;
struct list_head links;
struct list_head entity_notify;
struct mutex graph_mutex;
struct media_entity_graph pm_count_walk;
void * source_priv;
int (* enable_source) (struct media_entity *entity,struct media_pipeline *pipe);
void (* disable_source) (struct media_entity *entity);
int (* link_notify) (struct media_link *link, u32 flags,unsigned int notification);
};

MEMBERS

dev

Parent device

devnode

Media device node

model[32]

Device model name

driver_name[32]

Optional device driver name. If not set, calls to MEDIA_IOC_DEVICE_INFO will return dev->driver->name. This is needed for USB drivers for example, as otherwise they'll all appear as if the driver name was "usb".

serial[40]

Device serial number (optional)

bus_info[32]

Unique and stable device location identifier

hw_revision

Hardware device revision

driver_version

Device driver version

topology_version

Monotonic counter for storing the version of the graph topology. Should be incremented each time the topology changes.

id

Unique ID used on the last registered graph object

entity_internal_idx

Unique internal entity ID used by the graph traversal algorithms

entity_internal_idx_max

Allocated internal entity indices

entities

List of registered entities

interfaces

List of registered interfaces

pads

List of registered pads

links

List of registered links

entity_notify

List of registered entity_notify callbacks

graph_mutex

Protects access to struct media_device data

pm_count_walk

Graph walk for power state walk. Access serialised using graph_mutex.

source_priv

Driver Private data for enable/disable source handlers

enable_source

Enable Source Handler function pointer

disable_source

Disable Source Handler function pointer

link_notify

Link state change notification callback. This callback is called with the graph_mutex held.

DESCRIPTION

This structure represents an abstract high-level media device. It allows easy access to entities and provides basic media device-level support. The structure can be allocated directly or embedded in a larger structure.

The parent dev is a physical device. It must be set before registering the media device.

model is a descriptive model name exported through sysfs. It doesn't have to be unique.

enable_source is a handler to find source entity for the sink entity and activate the link between them if source entity is free. Drivers should call this handler before accessing the source.

disable_source is a handler to find source entity for the sink entity and deactivate the link between them. Drivers should call this handler to release the source.

NOTE

Bridge driver is expected to implement and set the handler when media_device is registered or when bridge driver finds the media_device during probe. Bridge driver sets source_priv with information necessary to run enable/disable source handlers.

Use-case: find tuner entity connected to the decoder entity and check if it is available, and activate the the link between them from enable_source and deactivate from disable_source.

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