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    Subject[PATCH v9 12/12] v4l: Make v4l2_subdev inherit from media_entity
    Date
    V4L2 subdevices are media entities. As such they need to inherit from
    (include) the media_entity structure.

    When registering/unregistering the subdevice, the media entity is
    automatically registered/unregistered. The entity is acquired on device
    open and released on device close.

    Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
    Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi>
    ---
    Documentation/video4linux/v4l2-framework.txt | 23 ++++++++++++++++
    drivers/media/video/v4l2-device.c | 36 +++++++++++++++++++++++---
    drivers/media/video/v4l2-subdev.c | 28 ++++++++++++++++++-
    include/media/v4l2-subdev.h | 6 ++++
    4 files changed, 87 insertions(+), 6 deletions(-)

    diff --git a/Documentation/video4linux/v4l2-framework.txt b/Documentation/video4linux/v4l2-framework.txt
    index 0627081..77d96f4 100644
    --- a/Documentation/video4linux/v4l2-framework.txt
    +++ b/Documentation/video4linux/v4l2-framework.txt
    @@ -268,6 +268,26 @@ A sub-device driver initializes the v4l2_subdev struct using:
    Afterwards you need to initialize subdev->name with a unique name and set the
    module owner. This is done for you if you use the i2c helper functions.

    +If integration with the media framework is needed, you must initialize the
    +media_entity struct embedded in the v4l2_subdev struct (entity field) by
    +calling media_entity_init():
    +
    + struct media_pad *pads = &my_sd->pads;
    + int err;
    +
    + err = media_entity_init(&sd->entity, npads, pads, 0);
    +
    +The pads array must have been previously initialized. There is no need to
    +manually set the struct media_entity type and name fields, but the revision
    +field must be initialized if needed.
    +
    +A reference to the entity will be automatically acquired/released when the
    +subdev device node (if any) is opened/closed.
    +
    +Don't forget to cleanup the media entity before the sub-device is destroyed:
    +
    + media_entity_cleanup(&sd->entity);
    +
    A device (bridge) driver needs to register the v4l2_subdev with the
    v4l2_device:

    @@ -277,6 +297,9 @@ This can fail if the subdev module disappeared before it could be registered.
    After this function was called successfully the subdev->dev field points to
    the v4l2_device.

    +If the v4l2_device parent device has a non-NULL mdev field, the sub-device
    +entity will be automatically registered with the media device.
    +
    You can unregister a sub-device using:

    v4l2_device_unregister_subdev(sd);
    diff --git a/drivers/media/video/v4l2-device.c b/drivers/media/video/v4l2-device.c
    index 0af46e4..259415b 100644
    --- a/drivers/media/video/v4l2-device.c
    +++ b/drivers/media/video/v4l2-device.c
    @@ -118,8 +118,11 @@ void v4l2_device_unregister(struct v4l2_device *v4l2_dev)
    EXPORT_SYMBOL_GPL(v4l2_device_unregister);

    int v4l2_device_register_subdev(struct v4l2_device *v4l2_dev,
    - struct v4l2_subdev *sd)
    + struct v4l2_subdev *sd)
    {
    +#if defined(CONFIG_MEDIA_CONTROLLER)
    + struct media_entity *entity = &sd->entity;
    +#endif
    int err;

    /* Check for valid input */
    @@ -147,6 +150,19 @@ int v4l2_device_register_subdev(struct v4l2_device *v4l2_dev,
    return err;
    }

    +#if defined(CONFIG_MEDIA_CONTROLLER)
    + /* Register the entity. */
    + if (v4l2_dev->mdev) {
    + err = media_device_register_entity(v4l2_dev->mdev, entity);
    + if (err < 0) {
    + if (sd->internal_ops && sd->internal_ops->unregistered)
    + sd->internal_ops->unregistered(sd);
    + module_put(sd->owner);
    + return err;
    + }
    + }
    +#endif
    +
    spin_lock(&v4l2_dev->lock);
    list_add_tail(&sd->list, &v4l2_dev->subdevs);
    spin_unlock(&v4l2_dev->lock);
    @@ -177,25 +193,37 @@ int v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev)
    sd->owner);
    if (err < 0)
    return err;
    +#if defined(CONFIG_MEDIA_CONTROLLER)
    + sd->entity.v4l.major = VIDEO_MAJOR;
    + sd->entity.v4l.minor = vdev->minor;
    +#endif
    }
    -
    return 0;
    }
    EXPORT_SYMBOL_GPL(v4l2_device_register_subdev_nodes);

    void v4l2_device_unregister_subdev(struct v4l2_subdev *sd)
    {
    + struct v4l2_device *v4l2_dev;
    +
    /* return if it isn't registered */
    if (sd == NULL || sd->v4l2_dev == NULL)
    return;

    - spin_lock(&sd->v4l2_dev->lock);
    + v4l2_dev = sd->v4l2_dev;
    +
    + spin_lock(&v4l2_dev->lock);
    list_del(&sd->list);
    - spin_unlock(&sd->v4l2_dev->lock);
    + spin_unlock(&v4l2_dev->lock);
    +
    if (sd->internal_ops && sd->internal_ops->unregistered)
    sd->internal_ops->unregistered(sd);
    sd->v4l2_dev = NULL;

    +#if defined(CONFIG_MEDIA_CONTROLLER)
    + if (v4l2_dev->mdev)
    + media_device_unregister_entity(&sd->entity);
    +#endif
    video_unregister_device(&sd->devnode);
    module_put(sd->owner);
    }
    diff --git a/drivers/media/video/v4l2-subdev.c b/drivers/media/video/v4l2-subdev.c
    index 9374406..29b7ddf 100644
    --- a/drivers/media/video/v4l2-subdev.c
    +++ b/drivers/media/video/v4l2-subdev.c
    @@ -35,7 +35,10 @@ static int subdev_open(struct file *file)
    {
    struct video_device *vdev = video_devdata(file);
    struct v4l2_subdev *sd = vdev_to_v4l2_subdev(vdev);
    - struct v4l2_fh *vfh;
    +#if defined(CONFIG_MEDIA_CONTROLLER)
    + struct media_entity *entity;
    +#endif
    + struct v4l2_fh *vfh = NULL;
    int ret;

    if (sd->flags & V4L2_SUBDEV_FL_HAS_EVENTS) {
    @@ -58,11 +61,20 @@ static int subdev_open(struct file *file)
    v4l2_fh_add(vfh);
    file->private_data = vfh;
    }
    -
    +#if defined(CONFIG_MEDIA_CONTROLLER)
    + if (sd->v4l2_dev->mdev) {
    + entity = media_entity_get(&sd->entity);
    + if (!entity) {
    + ret = -EBUSY;
    + goto err;
    + }
    + }
    +#endif
    return 0;

    err:
    if (vfh != NULL) {
    + v4l2_fh_del(vfh);
    v4l2_fh_exit(vfh);
    kfree(vfh);
    }
    @@ -72,8 +84,16 @@ err:

    static int subdev_close(struct file *file)
    {
    +#if defined(CONFIG_MEDIA_CONTROLLER)
    + struct video_device *vdev = video_devdata(file);
    + struct v4l2_subdev *sd = vdev_to_v4l2_subdev(vdev);
    +#endif
    struct v4l2_fh *vfh = file->private_data;

    +#if defined(CONFIG_MEDIA_CONTROLLER)
    + if (sd->v4l2_dev->mdev)
    + media_entity_put(&sd->entity);
    +#endif
    if (vfh != NULL) {
    v4l2_fh_del(vfh);
    v4l2_fh_exit(vfh);
    @@ -172,5 +192,9 @@ void v4l2_subdev_init(struct v4l2_subdev *sd, const struct v4l2_subdev_ops *ops)
    sd->grp_id = 0;
    sd->dev_priv = NULL;
    sd->host_priv = NULL;
    +#if defined(CONFIG_MEDIA_CONTROLLER)
    + sd->entity.name = sd->name;
    + sd->entity.type = MEDIA_ENT_T_V4L2_SUBDEV;
    +#endif
    }
    EXPORT_SYMBOL(v4l2_subdev_init);
    diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h
    index 3f4e0d1..c37d6e4 100644
    --- a/include/media/v4l2-subdev.h
    +++ b/include/media/v4l2-subdev.h
    @@ -21,6 +21,7 @@
    #ifndef _V4L2_SUBDEV_H
    #define _V4L2_SUBDEV_H

    +#include <media/media-entity.h>
    #include <media/v4l2-common.h>
    #include <media/v4l2-dev.h>
    #include <media/v4l2-mediabus.h>
    @@ -448,6 +449,9 @@ struct v4l2_subdev_internal_ops {
    stand-alone or embedded in a larger struct.
    */
    struct v4l2_subdev {
    +#if defined(CONFIG_MEDIA_CONTROLLER)
    + struct media_entity entity;
    +#endif
    struct list_head list;
    struct module *owner;
    u32 flags;
    @@ -470,6 +474,8 @@ struct v4l2_subdev {
    unsigned int nevents;
    };

    +#define media_entity_to_v4l2_subdev(ent) \
    + container_of(ent, struct v4l2_subdev, entity)
    #define vdev_to_v4l2_subdev(vdev) \
    container_of(vdev, struct v4l2_subdev, devnode)

    --
    1.7.3.4


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