Re: [RFC PATCH v7 10/13] media: uapi: Add V4L2_CTRL_TYPE_FIXED_POINT

[Hans Verkuil]

On 20/10/2023 11:30, Shengjiu Wang wrote:
> Fixed point controls are used by the user to configure
> a fixed point value in 64bits, which Q31.32 format.
> 
> Signed-off-by: Shengjiu Wang <shengjiu.wang@xxxxxxx>
> ---
>  Documentation/userspace-api/media/v4l/vidioc-queryctrl.rst  | 6 ++++++
>  .../userspace-api/media/videodev2.h.rst.exceptions          | 1 +
>  drivers/media/v4l2-core/v4l2-ctrls-api.c                    | 5 ++++-
>  drivers/media/v4l2-core/v4l2-ctrls-core.c                   | 2 ++
>  include/uapi/linux/videodev2.h                              | 1 +
>  5 files changed, 14 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/userspace-api/media/v4l/vidioc-queryctrl.rst b/Documentation/userspace-api/media/v4l/vidioc-queryctrl.rst
> index 4d38acafe8e1..2e15db0779f2 100644
> --- a/Documentation/userspace-api/media/v4l/vidioc-queryctrl.rst
> +++ b/Documentation/userspace-api/media/v4l/vidioc-queryctrl.rst
> @@ -549,6 +549,12 @@ See also the examples in :ref:`control`.
>        - n/a
>        - A struct :c:type:`v4l2_ctrl_av1_film_grain`, containing AV1 Film Grain
>          parameters for stateless video decoders.
> +    * - ``V4L2_CTRL_TYPE_FIXED_POINT``
> +      - n/a
> +      - n/a
> +      - n/a
> +      - A struct :c:type:`v4l2_ctrl_fixed_point`, containing parameter which is
> +        Q31.32 format.

No, this isn't a struct. It's a 64 bit integer.

Also search for INTEGER64 in this file, it's mentioned in the "default_value"
documentation, and _FIXED_POINT needs to be added to that text.

>  
>  .. raw:: latex
>  

You also need to update Documentation/userspace-api/media/v4l/vidioc-g-ext-ctrls.rst,
search for INTEGER64 in that file.

> diff --git a/Documentation/userspace-api/media/videodev2.h.rst.exceptions b/Documentation/userspace-api/media/videodev2.h.rst.exceptions
> index e61152bb80d1..2faa5a2015eb 100644
> --- a/Documentation/userspace-api/media/videodev2.h.rst.exceptions
> +++ b/Documentation/userspace-api/media/videodev2.h.rst.exceptions
> @@ -167,6 +167,7 @@ replace symbol V4L2_CTRL_TYPE_AV1_SEQUENCE :c:type:`v4l2_ctrl_type`
>  replace symbol V4L2_CTRL_TYPE_AV1_TILE_GROUP_ENTRY :c:type:`v4l2_ctrl_type`
>  replace symbol V4L2_CTRL_TYPE_AV1_FRAME :c:type:`v4l2_ctrl_type`
>  replace symbol V4L2_CTRL_TYPE_AV1_FILM_GRAIN :c:type:`v4l2_ctrl_type`
> +replace symbol V4L2_CTRL_TYPE_FIXED_POINT :c:type:`v4l2_ctrl_type`
>  
>  # V4L2 capability defines
>  replace define V4L2_CAP_VIDEO_CAPTURE device-capabilities
> diff --git a/drivers/media/v4l2-core/v4l2-ctrls-api.c b/drivers/media/v4l2-core/v4l2-ctrls-api.c
> index 002ea6588edf..e6a0fb8d6791 100644
> --- a/drivers/media/v4l2-core/v4l2-ctrls-api.c
> +++ b/drivers/media/v4l2-core/v4l2-ctrls-api.c
> @@ -57,6 +57,7 @@ static int ptr_to_user(struct v4l2_ext_control *c,
>  		return copy_to_user(c->string, ptr.p_char, len + 1) ?
>  		       -EFAULT : 0;
>  	case V4L2_CTRL_TYPE_INTEGER64:
> +	case V4L2_CTRL_TYPE_FIXED_POINT:
>  		c->value64 = *ptr.p_s64;
>  		break;
>  	default:
> @@ -132,6 +133,7 @@ static int user_to_new(struct v4l2_ext_control *c, struct v4l2_ctrl *ctrl)
>  
>  	switch (ctrl->type) {
>  	case V4L2_CTRL_TYPE_INTEGER64:
> +	case V4L2_CTRL_TYPE_FIXED_POINT:
>  		*ctrl->p_new.p_s64 = c->value64;
>  		break;
>  	case V4L2_CTRL_TYPE_STRING:
> @@ -540,7 +542,8 @@ static int validate_ctrls(struct v4l2_ext_controls *cs,
>  		 */
>  		if (ctrl->is_ptr)
>  			continue;
> -		if (ctrl->type == V4L2_CTRL_TYPE_INTEGER64)
> +		if (ctrl->type == V4L2_CTRL_TYPE_INTEGER64 ||
> +		    ctrl->type == V4L2_CTRL_TYPE_FIXED_POINT)
>  			p_new.p_s64 = &cs->controls[i].value64;
>  		else
>  			p_new.p_s32 = &cs->controls[i].value;
> diff --git a/drivers/media/v4l2-core/v4l2-ctrls-core.c b/drivers/media/v4l2-core/v4l2-ctrls-core.c
> index a662fb60f73f..9d50df0d9874 100644
> --- a/drivers/media/v4l2-core/v4l2-ctrls-core.c
> +++ b/drivers/media/v4l2-core/v4l2-ctrls-core.c
> @@ -1187,6 +1187,7 @@ static int std_validate_elem(const struct v4l2_ctrl *ctrl, u32 idx,
>  	case V4L2_CTRL_TYPE_INTEGER:
>  		return ROUND_TO_RANGE(ptr.p_s32[idx], u32, ctrl);
>  	case V4L2_CTRL_TYPE_INTEGER64:
> +	case V4L2_CTRL_TYPE_FIXED_POINT:
>  		/*
>  		 * We can't use the ROUND_TO_RANGE define here due to
>  		 * the u64 divide that needs special care.
> @@ -1779,6 +1780,7 @@ static struct v4l2_ctrl *v4l2_ctrl_new(struct v4l2_ctrl_handler *hdl,
>  	/* Prefill elem_size for all types handled by std_type_ops */
>  	switch ((u32)type) {
>  	case V4L2_CTRL_TYPE_INTEGER64:
> +	case V4L2_CTRL_TYPE_FIXED_POINT:
>  		elem_size = sizeof(s64);
>  		break;
>  	case V4L2_CTRL_TYPE_STRING:
> diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
> index 4ef08b3a9e39..ef8913d561bf 100644
> --- a/include/uapi/linux/videodev2.h
> +++ b/include/uapi/linux/videodev2.h
> @@ -1903,6 +1903,7 @@ enum v4l2_ctrl_type {
>  	V4L2_CTRL_TYPE_STRING        = 7,
>  	V4L2_CTRL_TYPE_BITMASK       = 8,
>  	V4L2_CTRL_TYPE_INTEGER_MENU  = 9,
> +	V4L2_CTRL_TYPE_FIXED_POINT   = 10,
>  
>  	/* Compound types are >= 0x0100 */
>  	V4L2_CTRL_COMPOUND_TYPES     = 0x0100,

Regards,

	Hans