Hi Mauro,
On Thursday 09 September 2010 03:25:38 Mauro Carvalho Chehab wrote:
> Em 20-08-2010 12:29, Laurent Pinchart escreveu:
> > 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.pinch...@ideasonboard.com>
> > Signed-off-by: Sakari Ailus <sakari.ai...@maxwell.research.nokia.com>
> > ---
> >
> > Documentation/video4linux/v4l2-framework.txt | 23 ++++++++++++++++++
> > drivers/media/video/v4l2-device.c | 32
> > +++++++++++++++++++++----- drivers/media/video/v4l2-subdev.c
> > | 27 +++++++++++++++++++++- include/media/v4l2-subdev.h
> > | 7 +++++
> > 4 files changed, 82 insertions(+), 7 deletions(-)
> >
> > diff --git a/Documentation/video4linux/v4l2-framework.txt
> > b/Documentation/video4linux/v4l2-framework.txt index 7ff4016..3416d93
> > 100644
> > --- a/Documentation/video4linux/v4l2-framework.txt
> > +++ b/Documentation/video4linux/v4l2-framework.txt
> >
> > @@ -263,6 +263,26 @@ 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:
> > @@ -272,6 +292,9 @@ 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 91452cd..4f74d01 100644
> > --- a/drivers/media/video/v4l2-device.c
> > +++ b/drivers/media/video/v4l2-device.c
> > @@ -114,10 +114,11 @@ 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)
> >
> > {
> >
> > + struct media_entity *entity = &sd->entity;
> >
> > struct video_device *vdev;
> >
> > - int ret = 0;
> > + int ret;
> >
> > /* Check for valid input */
> > if (v4l2_dev == NULL || sd == NULL || !sd->name[0])
> >
> > @@ -129,6 +130,15 @@ int v4l2_device_register_subdev(struct v4l2_device
> > *v4l2_dev,
> >
> > if (!try_module_get(sd->owner))
> >
> > return -ENODEV;
> >
> > + /* Register the entity. */
> > + if (v4l2_dev->mdev) {
> > + ret = media_device_register_entity(v4l2_dev->mdev, entity);
> > + if (ret < 0) {
> > + module_put(sd->owner);
> > + return ret;
> > + }
> > + }
> > +
> >
> > sd->v4l2_dev = v4l2_dev;
> > spin_lock(&v4l2_dev->lock);
> > list_add_tail(&sd->list, &v4l2_dev->subdevs);
> >
> > @@ -143,26 +153,36 @@ int v4l2_device_register_subdev(struct v4l2_device
> > *v4l2_dev,
> >
> > if (sd->flags & V4L2_SUBDEV_FL_HAS_DEVNODE) {
> >
> > ret = __video_register_device(vdev, VFL_TYPE_SUBDEV, -1, 1,
> >
> > sd->owner);
> >
> > - if (ret < 0)
> > + if (ret < 0) {
> >
> > v4l2_device_unregister_subdev(sd);
> >
> > + return ret;
> > + }
> >
> > }
> >
> > - return ret;
> > + entity->v4l.major = VIDEO_MAJOR;
> > + entity->v4l.minor = vdev->minor;
>
> Hmm... it needs to check if entity is not null.
Entity is set to
struct media_entity *entity = &sd->entity;
It can't be NULL.
> > + return 0;
> >
> > }
> > EXPORT_SYMBOL_GPL(v4l2_device_register_subdev);
> >
> > 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);
> >
> > sd->v4l2_dev = NULL;
> >
> > module_put(sd->owner);
> >
> > + if (v4l2_dev->mdev)
> > + media_device_unregister_entity(&sd->entity);
> >
> > video_unregister_device(&sd->devnode);
> >
> > }
> > EXPORT_SYMBOL_GPL(v4l2_device_unregister_subdev);
> >
> > diff --git a/drivers/media/video/v4l2-subdev.c
> > b/drivers/media/video/v4l2-subdev.c index b063195..1efa267 100644
> > --- a/drivers/media/video/v4l2-subdev.c
> > +++ b/drivers/media/video/v4l2-subdev.c
> > @@ -32,7 +32,8 @@ 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;
> > + struct media_entity *entity;
> > + struct v4l2_fh *vfh = NULL;
> >
> > int ret;
> >
> > if (!sd->initialized)
> >
> > @@ -59,10 +60,17 @@ static int subdev_open(struct file *file)
> >
> > file->private_data = vfh;
> >
> > }
> >
> > + entity = media_entity_get(&sd->entity);
> > + if (!entity) {
> > + ret = -EBUSY;
> > + goto err;
> > + }
> > +
>
> It needs to check if v4l2_dev->mdev is not null, as it makes no sense to
> get an entity if the driver is not using the media entity.
OK.
> > return 0;
> >
> > err:
> > if (vfh != NULL) {
> >
> > + v4l2_fh_del(vfh);
> >
> > v4l2_fh_exit(vfh);
> > kfree(vfh);
> >
> > }
> >
> > @@ -72,8 +80,12 @@ err:
> > static int subdev_close(struct file *file)
> > {
> >
> > + struct video_device *vdev = video_devdata(file);
> > + struct v4l2_subdev *sd = vdev_to_v4l2_subdev(vdev);
> >
> > struct v4l2_fh *vfh = file->private_data;
> >
> > + media_entity_put(&sd->entity);
>
> Same here: don't put it, if v4l2_dev->mdev = NULL (I think that you're
> already checking for it at media_entity_put).
>
> > +
> >
> > if (vfh != NULL) {
> >
> > v4l2_fh_del(vfh);
> > v4l2_fh_exit(vfh);
> >
> > @@ -172,5 +184,18 @@ void v4l2_subdev_init(struct v4l2_subdev *sd, const
> > struct v4l2_subdev_ops *ops)
> >
> > sd->grp_id = 0;
> > sd->priv = NULL;
> > sd->initialized = 1;
> >
> > + sd->entity.name = sd->name;
> > + sd->entity.type = MEDIA_ENTITY_TYPE_SUBDEV;
> >
> > }
> > EXPORT_SYMBOL(v4l2_subdev_init);
> >
> > +
> > +int v4l2_subdev_set_power(struct media_entity *entity, int power)
> > +{
> > + struct v4l2_subdev *sd = media_entity_to_v4l2_subdev(entity);
> > +
> > + dev_dbg(entity->parent->dev,
> > + "%s power%s\n", entity->name, power ? "on" : "off");
> > +
> > + return v4l2_subdev_call(sd, core, s_power, power);
> > +}
> > +EXPORT_SYMBOL_GPL(v4l2_subdev_set_power);
>
> Also, should do nothing if media entity is null.
>
> PS.: Not sure where this function is called, as the caller is not on this
> patch series. The better would be to add this together with the patch
> calling v4l2_subdev_set_power().
v4l2_subdev_set_power() is a helper meant to be assigned to struct
media_entity_operations::set_power in subdev drivers.
--
Regards,
Laurent Pinchart
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