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SubjectRe: [PATCH 1/2] [media] v4l: allow to register dev nodes for individual v4l2 subdevs
Hi Javier,

On Tue, Sep 04, 2018 at 01:30:17PM +0200, Javier Martinez Canillas wrote:
> Currently there's only a function to register device nodes for all subdevs
> of a v4l2 device that are marked with the V4L2_SUBDEV_FL_HAS_DEVNODE flag.
>
> But drivers may want to register device nodes for individual subdevices,
> so add a v4l2_device_register_subdev_node() for this purpose.
>
> A use case for this function is for media device drivers to register the
> device nodes in the v4l2 async notifier .bound callback instead of doing
> a registration for all subdevices in the .complete callback.

Thanks for the set.

I've been doing some work to add events to MC; with Hans's property API
set, assuming it could be used to tell the registration is complete, we
have all bits for a complete solution.

As the driver is buggy and fails to work correctly in the case if not every
sub-devices probes successfully, I see no reason to postpone applying the
two patches now.

One more comment below. (No need to resend just for that IMO.)

>
> Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
> ---
>
> drivers/media/v4l2-core/v4l2-device.c | 90 ++++++++++++++++-----------
> include/media/v4l2-device.h | 10 +++
> 2 files changed, 63 insertions(+), 37 deletions(-)
>
> diff --git a/drivers/media/v4l2-core/v4l2-device.c b/drivers/media/v4l2-core/v4l2-device.c
> index 3940e55c72f1..e5fc51b6604c 100644
> --- a/drivers/media/v4l2-core/v4l2-device.c
> +++ b/drivers/media/v4l2-core/v4l2-device.c
> @@ -222,9 +222,59 @@ static void v4l2_device_release_subdev_node(struct video_device *vdev)
> kfree(vdev);
> }
>
> -int v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev)
> +int v4l2_device_register_subdev_node(struct v4l2_device *v4l2_dev,
> + struct v4l2_subdev *sd)
> {
> struct video_device *vdev;
> + int err;
> +
> + if (!(sd->flags & V4L2_SUBDEV_FL_HAS_DEVNODE))
> + return -EINVAL;
> +
> + vdev = kzalloc(sizeof(*vdev), GFP_KERNEL);
> + if (!vdev)
> + return -ENOMEM;
> +
> + video_set_drvdata(vdev, sd);
> + strlcpy(vdev->name, sd->name, sizeof(vdev->name));
> + vdev->v4l2_dev = v4l2_dev;
> + vdev->fops = &v4l2_subdev_fops;
> + vdev->release = v4l2_device_release_subdev_node;
> + vdev->ctrl_handler = sd->ctrl_handler;
> + err = __video_register_device(vdev, VFL_TYPE_SUBDEV, -1, 1,
> + sd->owner);
> + if (err < 0) {
> + kfree(vdev);
> + return err;
> + }
> + sd->devnode = vdev;
> +#if defined(CONFIG_MEDIA_CONTROLLER)
> + sd->entity.info.dev.major = VIDEO_MAJOR;
> + sd->entity.info.dev.minor = vdev->minor;
> +
> + /* Interface is created by __video_register_device() */
> + if (vdev->v4l2_dev->mdev) {
> + struct media_link *link;
> +
> + link = media_create_intf_link(&sd->entity,
> + &vdev->intf_devnode->intf,
> + MEDIA_LNK_FL_ENABLED |
> + MEDIA_LNK_FL_IMMUTABLE);
> + if (!link) {
> + err = -ENOMEM;
> + video_unregister_device(sd->devnode);
> + return err;
> + }
> + }
> +#endif
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(v4l2_device_register_subdev_node);
> +
> +int v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev)
> +{
> +
> struct v4l2_subdev *sd;
> int err;
>
> @@ -238,43 +288,9 @@ int v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev)
> if (sd->devnode)
> continue;
>
> - vdev = kzalloc(sizeof(*vdev), GFP_KERNEL);
> - if (!vdev) {
> - err = -ENOMEM;
> - goto clean_up;
> - }
> -
> - video_set_drvdata(vdev, sd);
> - strlcpy(vdev->name, sd->name, sizeof(vdev->name));
> - vdev->v4l2_dev = v4l2_dev;
> - vdev->fops = &v4l2_subdev_fops;
> - vdev->release = v4l2_device_release_subdev_node;
> - vdev->ctrl_handler = sd->ctrl_handler;
> - err = __video_register_device(vdev, VFL_TYPE_SUBDEV, -1, 1,
> - sd->owner);
> - if (err < 0) {
> - kfree(vdev);
> + err = v4l2_device_register_subdev_node(v4l2_dev, sd);
> + if (err)
> goto clean_up;
> - }
> - sd->devnode = vdev;
> -#if defined(CONFIG_MEDIA_CONTROLLER)
> - sd->entity.info.dev.major = VIDEO_MAJOR;
> - sd->entity.info.dev.minor = vdev->minor;
> -
> - /* Interface is created by __video_register_device() */
> - if (vdev->v4l2_dev->mdev) {
> - struct media_link *link;
> -
> - link = media_create_intf_link(&sd->entity,
> - &vdev->intf_devnode->intf,
> - MEDIA_LNK_FL_ENABLED |
> - MEDIA_LNK_FL_IMMUTABLE);
> - if (!link) {
> - err = -ENOMEM;
> - goto clean_up;
> - }
> - }
> -#endif
> }
> return 0;
>
> diff --git a/include/media/v4l2-device.h b/include/media/v4l2-device.h
> index b330e4a08a6b..bf25418a1ad6 100644
> --- a/include/media/v4l2-device.h
> +++ b/include/media/v4l2-device.h
> @@ -185,6 +185,16 @@ int __must_check v4l2_device_register_subdev(struct v4l2_device *v4l2_dev,
> */
> void v4l2_device_unregister_subdev(struct v4l2_subdev *sd);
>
> +/**
> + * v4l2_device_register_subdev_node - Registers a device node for a subdev
> + * of the v4l2 device.
> + *
> + * @v4l2_dev: pointer to struct v4l2_device

struct -> &struct

> + * @sd: pointer to &struct v4l2_subdev
> + */
> +int __must_check v4l2_device_register_subdev_node(struct v4l2_device *v4l2_dev,
> + struct v4l2_subdev *sd);
> +
> /**
> * v4l2_device_register_subdev_nodes - Registers device nodes for all subdevs
> * of the v4l2 device that are marked with

--
Regards,

Sakari Ailus
sakari.ailus@linux.intel.com

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