diff options
author | André Fabian Silva Delgado <emulatorman@parabola.nu> | 2016-10-20 00:10:27 -0300 |
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committer | André Fabian Silva Delgado <emulatorman@parabola.nu> | 2016-10-20 00:10:27 -0300 |
commit | d0b2f91bede3bd5e3d24dd6803e56eee959c1797 (patch) | |
tree | 7fee4ab0509879c373c4f2cbd5b8a5be5b4041ee /include/media/media-device.h | |
parent | e914f8eb445e8f74b00303c19c2ffceaedd16a05 (diff) |
Linux-libre 4.8.2-gnupck-4.8.2-gnu
Diffstat (limited to 'include/media/media-device.h')
-rw-r--r-- | include/media/media-device.h | 260 |
1 files changed, 14 insertions, 246 deletions
diff --git a/include/media/media-device.h b/include/media/media-device.h index a9b33c473..281952423 100644 --- a/include/media/media-device.h +++ b/include/media/media-device.h @@ -29,237 +29,6 @@ #include <media/media-devnode.h> #include <media/media-entity.h> -/** - * DOC: Media Controller - * - * The media controller userspace API is documented in DocBook format in - * Documentation/DocBook/media/v4l/media-controller.xml. This document focus - * on the kernel-side implementation of the media framework. - * - * * Abstract media device model: - * - * Discovering a device internal topology, and configuring it at runtime, is one - * of the goals of the media framework. To achieve this, hardware devices are - * modelled as an oriented graph of building blocks called entities connected - * through pads. - * - * An entity is a basic media hardware building block. It can correspond to - * a large variety of logical blocks such as physical hardware devices - * (CMOS sensor for instance), logical hardware devices (a building block - * in a System-on-Chip image processing pipeline), DMA channels or physical - * connectors. - * - * A pad is a connection endpoint through which an entity can interact with - * other entities. Data (not restricted to video) produced by an entity - * flows from the entity's output to one or more entity inputs. Pads should - * not be confused with physical pins at chip boundaries. - * - * A link is a point-to-point oriented connection between two pads, either - * on the same entity or on different entities. Data flows from a source - * pad to a sink pad. - * - * - * * Media device: - * - * A media device is represented by a struct &media_device instance, defined in - * include/media/media-device.h. Allocation of the structure is handled by the - * media device driver, usually by embedding the &media_device instance in a - * larger driver-specific structure. - * - * Drivers register media device instances by calling - * __media_device_register() via the macro media_device_register() - * and unregistered by calling - * media_device_unregister(). - * - * * Entities, pads and links: - * - * - Entities - * - * Entities are represented by a struct &media_entity instance, defined in - * include/media/media-entity.h. The structure is usually embedded into a - * higher-level structure, such as a v4l2_subdev or video_device instance, - * although drivers can allocate entities directly. - * - * Drivers initialize entity pads by calling - * media_entity_pads_init(). - * - * Drivers register entities with a media device by calling - * media_device_register_entity() - * and unregistred by calling - * media_device_unregister_entity(). - * - * - Interfaces - * - * Interfaces are represented by a struct &media_interface instance, defined in - * include/media/media-entity.h. Currently, only one type of interface is - * defined: a device node. Such interfaces are represented by a struct - * &media_intf_devnode. - * - * Drivers initialize and create device node interfaces by calling - * media_devnode_create() - * and remove them by calling: - * media_devnode_remove(). - * - * - Pads - * - * Pads are represented by a struct &media_pad instance, defined in - * include/media/media-entity.h. Each entity stores its pads in a pads array - * managed by the entity driver. Drivers usually embed the array in a - * driver-specific structure. - * - * Pads are identified by their entity and their 0-based index in the pads - * array. - * Both information are stored in the &media_pad structure, making the - * &media_pad pointer the canonical way to store and pass link references. - * - * Pads have flags that describe the pad capabilities and state. - * - * %MEDIA_PAD_FL_SINK indicates that the pad supports sinking data. - * %MEDIA_PAD_FL_SOURCE indicates that the pad supports sourcing data. - * - * NOTE: One and only one of %MEDIA_PAD_FL_SINK and %MEDIA_PAD_FL_SOURCE must - * be set for each pad. - * - * - Links - * - * Links are represented by a struct &media_link instance, defined in - * include/media/media-entity.h. There are two types of links: - * - * 1. pad to pad links: - * - * Associate two entities via their PADs. Each entity has a list that points - * to all links originating at or targeting any of its pads. - * A given link is thus stored twice, once in the source entity and once in - * the target entity. - * - * Drivers create pad to pad links by calling: - * media_create_pad_link() and remove with media_entity_remove_links(). - * - * 2. interface to entity links: - * - * Associate one interface to a Link. - * - * Drivers create interface to entity links by calling: - * media_create_intf_link() and remove with media_remove_intf_links(). - * - * NOTE: - * - * Links can only be created after having both ends already created. - * - * Links have flags that describe the link capabilities and state. The - * valid values are described at media_create_pad_link() and - * media_create_intf_link(). - * - * Graph traversal: - * - * The media framework provides APIs to iterate over entities in a graph. - * - * To iterate over all entities belonging to a media device, drivers can use - * the media_device_for_each_entity macro, defined in - * include/media/media-device.h. - * - * struct media_entity *entity; - * - * media_device_for_each_entity(entity, mdev) { - * // entity will point to each entity in turn - * ... - * } - * - * Drivers might also need to iterate over all entities in a graph that can be - * reached only through enabled links starting at a given entity. The media - * framework provides a depth-first graph traversal API for that purpose. - * - * Note that graphs with cycles (whether directed or undirected) are *NOT* - * supported by the graph traversal API. To prevent infinite loops, the graph - * traversal code limits the maximum depth to MEDIA_ENTITY_ENUM_MAX_DEPTH, - * currently defined as 16. - * - * Drivers initiate a graph traversal by calling - * media_entity_graph_walk_start() - * - * The graph structure, provided by the caller, is initialized to start graph - * traversal at the given entity. - * - * Drivers can then retrieve the next entity by calling - * media_entity_graph_walk_next() - * - * When the graph traversal is complete the function will return NULL. - * - * Graph traversal can be interrupted at any moment. No cleanup function call - * is required and the graph structure can be freed normally. - * - * Helper functions can be used to find a link between two given pads, or a pad - * connected to another pad through an enabled link - * media_entity_find_link() and media_entity_remote_pad() - * - * Use count and power handling: - * - * Due to the wide differences between drivers regarding power management - * needs, the media controller does not implement power management. However, - * the &media_entity structure includes a use_count field that media drivers - * can use to track the number of users of every entity for power management - * needs. - * - * The &media_entity.@use_count field is owned by media drivers and must not be - * touched by entity drivers. Access to the field must be protected by the - * &media_device.@graph_mutex lock. - * - * Links setup: - * - * Link properties can be modified at runtime by calling - * media_entity_setup_link() - * - * Pipelines and media streams: - * - * When starting streaming, drivers must notify all entities in the pipeline to - * prevent link states from being modified during streaming by calling - * media_entity_pipeline_start(). - * - * The function will mark all entities connected to the given entity through - * enabled links, either directly or indirectly, as streaming. - * - * The &media_pipeline instance pointed to by the pipe argument will be stored - * in every entity in the pipeline. Drivers should embed the &media_pipeline - * structure in higher-level pipeline structures and can then access the - * pipeline through the &media_entity pipe field. - * - * Calls to media_entity_pipeline_start() can be nested. The pipeline pointer - * must be identical for all nested calls to the function. - * - * media_entity_pipeline_start() may return an error. In that case, it will - * clean up any of the changes it did by itself. - * - * When stopping the stream, drivers must notify the entities with - * media_entity_pipeline_stop(). - * - * If multiple calls to media_entity_pipeline_start() have been made the same - * number of media_entity_pipeline_stop() calls are required to stop streaming. - * The &media_entity pipe field is reset to NULL on the last nested stop call. - * - * Link configuration will fail with -%EBUSY by default if either end of the - * link is a streaming entity. Links that can be modified while streaming must - * be marked with the %MEDIA_LNK_FL_DYNAMIC flag. - * - * If other operations need to be disallowed on streaming entities (such as - * changing entities configuration parameters) drivers can explicitly check the - * media_entity stream_count field to find out if an entity is streaming. This - * operation must be done with the media_device graph_mutex held. - * - * Link validation: - * - * Link validation is performed by media_entity_pipeline_start() for any - * entity which has sink pads in the pipeline. The - * &media_entity.@link_validate() callback is used for that purpose. In - * @link_validate() callback, entity driver should check that the properties of - * the source pad of the connected entity and its own sink pad match. It is up - * to the type of the entity (and in the end, the properties of the hardware) - * what matching actually means. - * - * Subsystems should facilitate link validation by providing subsystem specific - * helper functions to provide easy access for commonly needed information, and - * in the end provide a way to use driver-specific callbacks. - */ - struct ida; struct device; @@ -347,7 +116,7 @@ struct media_entity_notify { struct media_device { /* dev->driver_data points to this struct. */ struct device *dev; - struct media_devnode devnode; + struct media_devnode *devnode; char model[32]; char driver_name[32]; @@ -393,9 +162,6 @@ struct usb_device; #define MEDIA_DEV_NOTIFY_PRE_LINK_CH 0 #define MEDIA_DEV_NOTIFY_POST_LINK_CH 1 -/* media_devnode to media_device */ -#define to_media_device(node) container_of(node, struct media_device, devnode) - /** * media_entity_enum_init - Initialise an entity enumeration * @@ -476,13 +242,11 @@ void media_device_cleanup(struct media_device *mdev); * without breaking binary compatibility. The version major must be * incremented when binary compatibility is broken. * - * Notes: + * .. note:: * - * Upon successful registration a character device named media[0-9]+ is created. - * The device major and minor numbers are dynamic. The model name is exported as - * a sysfs attribute. + * #) Upon successful registration a character device named media[0-9]+ is created. The device major and minor numbers are dynamic. The model name is exported as a sysfs attribute. * - * Unregistering a media device that hasn't been registered is *NOT* safe. + * #) Unregistering a media device that hasn't been registered is **NOT** safe. * * Return: returns zero on success or a negative error code. */ @@ -530,14 +294,16 @@ void media_device_unregister(struct media_device *mdev); * This can be used to report the default audio and video devices or the * default camera sensor. * - * NOTE: Drivers should set the entity function before calling this function. - * Please notice that the values %MEDIA_ENT_F_V4L2_SUBDEV_UNKNOWN and - * %MEDIA_ENT_F_UNKNOWN should not be used by the drivers. + * .. note:: + * + * Drivers should set the entity function before calling this function. + * Please notice that the values %MEDIA_ENT_F_V4L2_SUBDEV_UNKNOWN and + * %MEDIA_ENT_F_UNKNOWN should not be used by the drivers. */ int __must_check media_device_register_entity(struct media_device *mdev, struct media_entity *entity); -/* +/** * media_device_unregister_entity() - unregisters a media entity. * * @entity: pointer to struct &media_entity to be unregistered @@ -551,8 +317,10 @@ int __must_check media_device_register_entity(struct media_device *mdev, * When a media device is unregistered, all its entities are unregistered * automatically. No manual entities unregistration is then required. * - * Note: the media_entity instance itself must be freed explicitly by - * the driver if required. + * .. note:: + * + * The media_entity instance itself must be freed explicitly by + * the driver if required. */ void media_device_unregister_entity(struct media_entity *entity); |