Hi Hans,
Thanks for the patch!
On Fri, May 01, 2015 at 01:33:48PM +0200, Hans Verkuil wrote:
> From: Hans Verkuil <hans.verkuil@xxxxxxxxx>
>
> While normal video/radio/vbi/swradio nodes have a proper QUERYCAP ioctl
> that apps can call to determine that it is indeed a V4L2 device, there
> is currently no equivalent for v4l-subdev nodes. Adding this ioctl will
> solve that, and it will allow utilities like v4l2-compliance to be used
> with these devices as well.
>
> Signed-off-by: Hans Verkuil <hans.verkuil@xxxxxxxxx>
> ---
> drivers/media/v4l2-core/v4l2-subdev.c | 19 +++++++++++++++++++
> include/uapi/linux/v4l2-subdev.h | 12 ++++++++++++
> 2 files changed, 31 insertions(+)
>
> diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
> index 6359606..2ab1f7d 100644
> --- a/drivers/media/v4l2-core/v4l2-subdev.c
> +++ b/drivers/media/v4l2-core/v4l2-subdev.c
> @@ -25,6 +25,7 @@
> #include <linux/types.h>
> #include <linux/videodev2.h>
> #include <linux/export.h>
> +#include <linux/version.h>
>
> #include <media/v4l2-ctrls.h>
> #include <media/v4l2-device.h>
> @@ -187,6 +188,24 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
> #endif
>
> switch (cmd) {
> + case VIDIOC_SUBDEV_QUERYCAP: {
> + struct v4l2_subdev_capability *cap = arg;
> +
> + cap->version = LINUX_VERSION_CODE;
> + cap->device_caps = 0;
> + cap->pads = 0;
> + cap->entity_id = 0;
> +#if defined(CONFIG_MEDIA_CONTROLLER)
> + if (sd->entity.parent) {
> + cap->device_caps = V4L2_SUBDEV_CAP_ENTITY;
> + cap->pads = sd->entity.num_pads;
> + cap->entity_id = sd->entity.id;
> + }
> +#endif
> + memset(cap->reserved, 0, sizeof(cap->reserved));
> + break;
> + }
> +
> case VIDIOC_QUERYCTRL:
> return v4l2_queryctrl(vfh->ctrl_handler, arg);
>
> diff --git a/include/uapi/linux/v4l2-subdev.h b/include/uapi/linux/v4l2-subdev.h
> index dbce2b5..e48b9fd 100644
> --- a/include/uapi/linux/v4l2-subdev.h
> +++ b/include/uapi/linux/v4l2-subdev.h
> @@ -154,9 +154,21 @@ struct v4l2_subdev_selection {
> __u32 reserved[8];
> };
>
> +struct v4l2_subdev_capability {
> + __u32 version;
> + __u32 device_caps;
This is called capabilities in struct v4l2_capability. I'd follow the same
pattern.
> + __u32 pads;
> + __u32 entity_id;
What's the use case for the entity_id field btw.? Supposing that the user
wouldn't be using the MC interface to obtain it, is the entity_id relevant
in this context? Or is your intent first open the sub-device, and then find
out more information on the entity?
> + __u32 reserved[48];
Why 48?
As memory is typically allocated in powers of two (or n^2 + (n-1)^2), how
about aligning it accordingly? I don't think we lose anything by making this
e.g. 60. Although 28 would probably suffice as well (or 29 with the pads
field removed as discussed). Even that much sounds like a lot.
> +};
> +
> +/* This v4l2_subdev is also a media entity and the entity_id field is valid */
> +#define V4L2_SUBDEV_CAP_ENTITY (1 << 0)
> +
> /* Backwards compatibility define --- to be removed */
> #define v4l2_subdev_edid v4l2_edid
>
> +#define VIDIOC_SUBDEV_QUERYCAP _IOR('V', 0, struct v4l2_subdev_capability)
> #define VIDIOC_SUBDEV_G_FMT _IOWR('V', 4, struct v4l2_subdev_format)
> #define VIDIOC_SUBDEV_S_FMT _IOWR('V', 5, struct v4l2_subdev_format)
> #define VIDIOC_SUBDEV_G_FRAME_INTERVAL _IOWR('V', 21, struct v4l2_subdev_frame_interval)
--
Kind regards,
Sakari Ailus
e-mail: sakari.ailus@xxxxxx XMPP: sailus@xxxxxxxxxxxxxx
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