diff mbox series

[v12,06/11] v4l2-ctrls: add support for V4L2_CTRL_WHICH_MIN/MAX_VAL

Message ID 20230817071750.2830271-7-yunkec@google.com
State Superseded
Headers show
Series Implement UVC v1.5 ROI | expand

Commit Message

Yunke Cao Aug. 17, 2023, 7:17 a.m. UTC
From: Hans Verkuil <hverkuil-cisco@xs4all.nl>

Add the capability of retrieving the min and max values of a
compound control.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Yunke Cao <yunkec@google.com>
---
Changelog since v11:
- Added a flag V4L2_CTRL_FLAG_HAS_WHICH_MIN_MAX.
- Modified std_min/max_compound() to be void function. Moved the check of
  whether WHICH_MIN/MAX_VAL into prepare_ext_ctrls(), and return EINVAL.
- Modified documentations to reflect this change.
Changelog since v10:
- No change.
Changelog since v9:
- No change.
Changelog since v8:
- Return ENODATA when min/max is not implemented. Document this behavior.
- Created a shared helper function __v4l2_ctrl_type_op_init that takes "which"
  as a parameter. Call it in def, min and max operations.
Changelog since v7:
- Document that the definition of the min/max are provided by compound controls
  are defined in control documentation.
- Return error, instead of zeroed memory for v4l2_ctrl_ptr_create(NULL).

git am from https://lore.kernel.org/all/20191119113457.57833-3-hverkuil-cisco@xs4all.nl/
- Fixed some merge conflits.
- Fixed the build error in drivers/media/platform/qcom/venus.

 .../media/v4l/vidioc-g-ext-ctrls.rst          |  16 +-
 .../media/v4l/vidioc-queryctrl.rst            |   9 +-
 .../media/videodev2.h.rst.exceptions          |   3 +
 drivers/media/i2c/imx214.c                    |   5 +-
 .../media/platform/qcom/venus/venc_ctrls.c    |   9 +-
 drivers/media/v4l2-core/v4l2-ctrls-api.c      |  54 ++++--
 drivers/media/v4l2-core/v4l2-ctrls-core.c     | 160 +++++++++++++++---
 drivers/media/v4l2-core/v4l2-ioctl.c          |   4 +-
 include/media/v4l2-ctrls.h                    |  34 +++-
 include/uapi/linux/videodev2.h                |   3 +
 10 files changed, 252 insertions(+), 45 deletions(-)

Comments

Yunke Cao Aug. 18, 2023, 1:48 a.m. UTC | #1
Hi Hans,

I updated the patch based on your comments. Can you take another look?

Thanks!
Yunke

On Thu, Aug 17, 2023 at 4:18 PM Yunke Cao <yunkec@google.com> wrote:
>
> From: Hans Verkuil <hverkuil-cisco@xs4all.nl>
>
> Add the capability of retrieving the min and max values of a
> compound control.
>
> Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
> Signed-off-by: Yunke Cao <yunkec@google.com>
> ---
> Changelog since v11:
> - Added a flag V4L2_CTRL_FLAG_HAS_WHICH_MIN_MAX.
> - Modified std_min/max_compound() to be void function. Moved the check of
>   whether WHICH_MIN/MAX_VAL into prepare_ext_ctrls(), and return EINVAL.
> - Modified documentations to reflect this change.
> Changelog since v10:
> - No change.
> Changelog since v9:
> - No change.
> Changelog since v8:
> - Return ENODATA when min/max is not implemented. Document this behavior.
> - Created a shared helper function __v4l2_ctrl_type_op_init that takes "which"
>   as a parameter. Call it in def, min and max operations.
> Changelog since v7:
> - Document that the definition of the min/max are provided by compound controls
>   are defined in control documentation.
> - Return error, instead of zeroed memory for v4l2_ctrl_ptr_create(NULL).
>
> git am from https://lore.kernel.org/all/20191119113457.57833-3-hverkuil-cisco@xs4all.nl/
> - Fixed some merge conflits.
> - Fixed the build error in drivers/media/platform/qcom/venus.
>
>  .../media/v4l/vidioc-g-ext-ctrls.rst          |  16 +-
>  .../media/v4l/vidioc-queryctrl.rst            |   9 +-
>  .../media/videodev2.h.rst.exceptions          |   3 +
>  drivers/media/i2c/imx214.c                    |   5 +-
>  .../media/platform/qcom/venus/venc_ctrls.c    |   9 +-
>  drivers/media/v4l2-core/v4l2-ctrls-api.c      |  54 ++++--
>  drivers/media/v4l2-core/v4l2-ctrls-core.c     | 160 +++++++++++++++---
>  drivers/media/v4l2-core/v4l2-ioctl.c          |   4 +-
>  include/media/v4l2-ctrls.h                    |  34 +++-
>  include/uapi/linux/videodev2.h                |   3 +
>  10 files changed, 252 insertions(+), 45 deletions(-)
>
> diff --git a/Documentation/userspace-api/media/v4l/vidioc-g-ext-ctrls.rst b/Documentation/userspace-api/media/v4l/vidioc-g-ext-ctrls.rst
> index 7b1001d11f9c..b4bf016411d3 100644
> --- a/Documentation/userspace-api/media/v4l/vidioc-g-ext-ctrls.rst
> +++ b/Documentation/userspace-api/media/v4l/vidioc-g-ext-ctrls.rst
> @@ -330,14 +330,26 @@ still cause this situation.
>        - Which value of the control to get/set/try.
>      * - :cspan:`2` ``V4L2_CTRL_WHICH_CUR_VAL`` will return the current value of
>         the control, ``V4L2_CTRL_WHICH_DEF_VAL`` will return the default
> +       value of the control, ``V4L2_CTRL_WHICH_MIN_VAL`` will return the minimum
> +       value of the control, ``V4L2_CTRL_WHICH_MAX_VAL`` will return the maximum
>         value of the control and ``V4L2_CTRL_WHICH_REQUEST_VAL`` indicates that
>         these controls have to be retrieved from a request or tried/set for
>         a request. In the latter case the ``request_fd`` field contains the
>         file descriptor of the request that should be used. If the device
>         does not support requests, then ``EACCES`` will be returned.
>
> -       When using ``V4L2_CTRL_WHICH_DEF_VAL`` be aware that you can only
> -       get the default value of the control, you cannot set or try it.
> +       When using ``V4L2_CTRL_WHICH_DEF_VAL``, ``V4L2_CTRL_WHICH_MIN_VAL``
> +       or ``V4L2_CTRL_WHICH_MAX_VAL`` be aware that you can only get the
> +       default/minimum/maximum value of the control, you cannot set or try it.
> +
> +       Whether a control supports querying the minimum and maximum values using
> +       ``V4L2_CTRL_WHICH_MIN_VAL`` and ``V4L2_CTRL_WHICH_MAX_VAL`` is indicated
> +       by the ``V4L2_CTRL_FLAG_HAS_WHICH_MIN_MAX`` flag. Most non-compound
> +       control types support this. For controls with compound types, the
> +       definition of minimum/maximum values are provided by
> +       the control documentation. If a compound control does not document the
> +       meaning of minimum/maximum value, then querying the minimum or maximum
> +       value will result in the error code -EINVAL.
>
>         For backwards compatibility you can also use a control class here
>         (see :ref:`ctrl-class`). In that case all controls have to
> diff --git a/Documentation/userspace-api/media/v4l/vidioc-queryctrl.rst b/Documentation/userspace-api/media/v4l/vidioc-queryctrl.rst
> index 56d5c8b0b88b..b39f7e27bbbe 100644
> --- a/Documentation/userspace-api/media/v4l/vidioc-queryctrl.rst
> +++ b/Documentation/userspace-api/media/v4l/vidioc-queryctrl.rst
> @@ -447,7 +447,10 @@ See also the examples in :ref:`control`.
>        - n/a
>        - A struct :c:type:`v4l2_rect`, containing a rectangle described by
>         the position of its top-left corner, the width and the height. Units
> -       depend on the use case.
> +       depend on the use case. Support for ``V4L2_CTRL_WHICH_MIN_VAL`` and
> +       ``V4L2_CTRL_WHICH_MAX_VAL`` is optional and depends on the
> +       ``V4L2_CTRL_FLAG_HAS_WHICH_MIN_MAX`` flag. See the documentation of
> +       the specific control on how to interpret the minimum and maximum values.
>      * - ``V4L2_CTRL_TYPE_H264_SPS``
>        - n/a
>        - n/a
> @@ -664,6 +667,10 @@ See also the examples in :ref:`control`.
>         ``dims[0]``. So setting the control with a differently sized
>         array will change the ``elems`` field when the control is
>         queried afterwards.
> +    * - ``V4L2_CTRL_FLAG_HAS_WHICH_MIN_MAX``
> +      - 0x1000
> +      - This control supports getting minimum and maximum values using
> +      vidioc_g_ext_ctrls with V4L2_CTRL_WHICH_MIN/MAX_VAL.
>
>  Return Value
>  ============
> diff --git a/Documentation/userspace-api/media/videodev2.h.rst.exceptions b/Documentation/userspace-api/media/videodev2.h.rst.exceptions
> index c46082ef0e4d..a417af25e9a4 100644
> --- a/Documentation/userspace-api/media/videodev2.h.rst.exceptions
> +++ b/Documentation/userspace-api/media/videodev2.h.rst.exceptions
> @@ -393,6 +393,7 @@ replace define V4L2_CTRL_FLAG_HAS_PAYLOAD control-flags
>  replace define V4L2_CTRL_FLAG_EXECUTE_ON_WRITE control-flags
>  replace define V4L2_CTRL_FLAG_MODIFY_LAYOUT control-flags
>  replace define V4L2_CTRL_FLAG_DYNAMIC_ARRAY control-flags
> +replace define V4L2_CTRL_FLAG_HAS_WHICH_MIN_MAX control-flags
>
>  replace define V4L2_CTRL_FLAG_NEXT_CTRL control
>  replace define V4L2_CTRL_FLAG_NEXT_COMPOUND control
> @@ -567,6 +568,8 @@ ignore define V4L2_CTRL_DRIVER_PRIV
>  ignore define V4L2_CTRL_MAX_DIMS
>  ignore define V4L2_CTRL_WHICH_CUR_VAL
>  ignore define V4L2_CTRL_WHICH_DEF_VAL
> +ignore define V4L2_CTRL_WHICH_MIN_VAL
> +ignore define V4L2_CTRL_WHICH_MAX_VAL
>  ignore define V4L2_CTRL_WHICH_REQUEST_VAL
>  ignore define V4L2_OUT_CAP_CUSTOM_TIMINGS
>  ignore define V4L2_CID_MAX_CTRLS
> diff --git a/drivers/media/i2c/imx214.c b/drivers/media/i2c/imx214.c
> index 2f9c8582f940..8db4a5eb1737 100644
> --- a/drivers/media/i2c/imx214.c
> +++ b/drivers/media/i2c/imx214.c
> @@ -1037,7 +1037,10 @@ static int imx214_probe(struct i2c_client *client)
>         imx214->unit_size = v4l2_ctrl_new_std_compound(&imx214->ctrls,
>                                 NULL,
>                                 V4L2_CID_UNIT_CELL_SIZE,
> -                               v4l2_ctrl_ptr_create((void *)&unit_size));
> +                               v4l2_ctrl_ptr_create((void *)&unit_size),
> +                               v4l2_ctrl_ptr_create(NULL),
> +                               v4l2_ctrl_ptr_create(NULL));
> +
>         ret = imx214->ctrls.error;
>         if (ret) {
>                 dev_err(&client->dev, "%s control init failed (%d)\n",
> diff --git a/drivers/media/platform/qcom/venus/venc_ctrls.c b/drivers/media/platform/qcom/venus/venc_ctrls.c
> index 7468e43800a9..28eca8f9d148 100644
> --- a/drivers/media/platform/qcom/venus/venc_ctrls.c
> +++ b/drivers/media/platform/qcom/venus/venc_ctrls.c
> @@ -607,11 +607,16 @@ int venc_ctrl_init(struct venus_inst *inst)
>
>         v4l2_ctrl_new_std_compound(&inst->ctrl_handler, &venc_ctrl_ops,
>                                    V4L2_CID_COLORIMETRY_HDR10_CLL_INFO,
> -                                  v4l2_ctrl_ptr_create(&p_hdr10_cll));
> +                                  v4l2_ctrl_ptr_create(&p_hdr10_cll),
> +                                  v4l2_ctrl_ptr_create(NULL),
> +                                  v4l2_ctrl_ptr_create(NULL));
>
>         v4l2_ctrl_new_std_compound(&inst->ctrl_handler, &venc_ctrl_ops,
>                                    V4L2_CID_COLORIMETRY_HDR10_MASTERING_DISPLAY,
> -                                  v4l2_ctrl_ptr_create((void *)&p_hdr10_mastering));
> +                                  v4l2_ctrl_ptr_create((void *)&p_hdr10_mastering),
> +                                  v4l2_ctrl_ptr_create(NULL),
> +                                  v4l2_ctrl_ptr_create(NULL));
> +
>
>         v4l2_ctrl_new_std_menu(&inst->ctrl_handler, &venc_ctrl_ops,
>                                V4L2_CID_MPEG_VIDEO_INTRA_REFRESH_PERIOD_TYPE,
> diff --git a/drivers/media/v4l2-core/v4l2-ctrls-api.c b/drivers/media/v4l2-core/v4l2-ctrls-api.c
> index 002ea6588edf..d022e1ed4835 100644
> --- a/drivers/media/v4l2-core/v4l2-ctrls-api.c
> +++ b/drivers/media/v4l2-core/v4l2-ctrls-api.c
> @@ -94,6 +94,22 @@ static int def_to_user(struct v4l2_ext_control *c, struct v4l2_ctrl *ctrl)
>         return ptr_to_user(c, ctrl, ctrl->p_new);
>  }
>
> +/* Helper function: copy the minimum control value back to the caller */
> +static int min_to_user(struct v4l2_ext_control *c, struct v4l2_ctrl *ctrl)
> +{
> +       ctrl->type_ops->minimum(ctrl, 0, ctrl->p_new);
> +
> +       return ptr_to_user(c, ctrl, ctrl->p_new);
> +}
> +
> +/* Helper function: copy the maximum control value back to the caller */
> +static int max_to_user(struct v4l2_ext_control *c, struct v4l2_ctrl *ctrl)
> +{
> +       ctrl->type_ops->maximum(ctrl, 0, ctrl->p_new);
> +
> +       return ptr_to_user(c, ctrl, ctrl->p_new);
> +}
> +
>  /* Helper function: copy the caller-provider value as the new control value */
>  static int user_to_new(struct v4l2_ext_control *c, struct v4l2_ctrl *ctrl)
>  {
> @@ -229,8 +245,8 @@ static int prepare_ext_ctrls(struct v4l2_ctrl_handler *hdl,
>                 cs->error_idx = i;
>
>                 if (cs->which &&
> -                   cs->which != V4L2_CTRL_WHICH_DEF_VAL &&
> -                   cs->which != V4L2_CTRL_WHICH_REQUEST_VAL &&
> +                   (cs->which < V4L2_CTRL_WHICH_DEF_VAL ||
> +                    cs->which > V4L2_CTRL_WHICH_MAX_VAL) &&
>                     V4L2_CTRL_ID2WHICH(id) != cs->which) {
>                         dprintk(vdev,
>                                 "invalid which 0x%x or control id 0x%x\n",
> @@ -259,6 +275,15 @@ static int prepare_ext_ctrls(struct v4l2_ctrl_handler *hdl,
>                         return -EINVAL;
>                 }
>
> +               if (!(ctrl->flags & V4L2_CTRL_FLAG_HAS_WHICH_MIN_MAX) &&
> +                   (cs->which == V4L2_CTRL_WHICH_MIN_VAL ||
> +                    cs->which == V4L2_CTRL_WHICH_MAX_VAL)) {
> +                       dprintk(vdev,
> +                               "invalid which 0x%x or control id 0x%x\n",
> +                               cs->which, id);
> +                       return -EINVAL;
> +               }
> +
>                 if (ctrl->cluster[0]->ncontrols > 1)
>                         have_clusters = true;
>                 if (ctrl->cluster[0] != ctrl)
> @@ -368,8 +393,8 @@ static int prepare_ext_ctrls(struct v4l2_ctrl_handler *hdl,
>   */
>  static int class_check(struct v4l2_ctrl_handler *hdl, u32 which)
>  {
> -       if (which == 0 || which == V4L2_CTRL_WHICH_DEF_VAL ||
> -           which == V4L2_CTRL_WHICH_REQUEST_VAL)
> +       if (which == 0 || (which >= V4L2_CTRL_WHICH_DEF_VAL &&
> +                          which <= V4L2_CTRL_WHICH_MAX_VAL))
>                 return 0;
>         return find_ref_lock(hdl, which | 1) ? 0 : -EINVAL;
>  }
> @@ -389,10 +414,12 @@ int v4l2_g_ext_ctrls_common(struct v4l2_ctrl_handler *hdl,
>         struct v4l2_ctrl_helper *helpers = helper;
>         int ret;
>         int i, j;
> -       bool is_default, is_request;
> +       bool is_default, is_request, is_min, is_max;
>
>         is_default = (cs->which == V4L2_CTRL_WHICH_DEF_VAL);
>         is_request = (cs->which == V4L2_CTRL_WHICH_REQUEST_VAL);
> +       is_min = (cs->which == V4L2_CTRL_WHICH_MIN_VAL);
> +       is_max = (cs->which == V4L2_CTRL_WHICH_MAX_VAL);
>
>         cs->error_idx = cs->count;
>         cs->which = V4L2_CTRL_ID2WHICH(cs->which);
> @@ -432,13 +459,14 @@ int v4l2_g_ext_ctrls_common(struct v4l2_ctrl_handler *hdl,
>
>                 /*
>                  * g_volatile_ctrl will update the new control values.
> -                * This makes no sense for V4L2_CTRL_WHICH_DEF_VAL and
> +                * This makes no sense for V4L2_CTRL_WHICH_DEF_VAL,
> +                * V4L2_CTRL_WHICH_MIN_VAL, V4L2_CTRL_WHICH_MAX_VAL and
>                  * V4L2_CTRL_WHICH_REQUEST_VAL. In the case of requests
>                  * it is v4l2_ctrl_request_complete() that copies the
>                  * volatile controls at the time of request completion
>                  * to the request, so you don't want to do that again.
>                  */
> -               if (!is_default && !is_request &&
> +               if (!is_default && !is_request && !is_min && !is_max &&
>                     ((master->flags & V4L2_CTRL_FLAG_VOLATILE) ||
>                     (master->has_volatiles && !is_cur_manual(master)))) {
>                         for (j = 0; j < master->ncontrols; j++)
> @@ -467,6 +495,10 @@ int v4l2_g_ext_ctrls_common(struct v4l2_ctrl_handler *hdl,
>                                 ret = -ENOMEM;
>                         else if (is_request && ref->p_req_valid)
>                                 ret = req_to_user(cs->controls + idx, ref);
> +                       else if (is_min)
> +                               ret = min_to_user(cs->controls + idx, ref->ctrl);
> +                       else if (is_max)
> +                               ret = max_to_user(cs->controls + idx, ref->ctrl);
>                         else if (is_volatile)
>                                 ret = new_to_user(cs->controls + idx, ref->ctrl);
>                         else
> @@ -564,9 +596,11 @@ int try_set_ext_ctrls_common(struct v4l2_fh *fh,
>
>         cs->error_idx = cs->count;
>
> -       /* Default value cannot be changed */
> -       if (cs->which == V4L2_CTRL_WHICH_DEF_VAL) {
> -               dprintk(vdev, "%s: cannot change default value\n",
> +       /* Default/minimum/maximum values cannot be changed */
> +       if (cs->which == V4L2_CTRL_WHICH_DEF_VAL ||
> +           cs->which == V4L2_CTRL_WHICH_MIN_VAL ||
> +           cs->which == V4L2_CTRL_WHICH_MAX_VAL) {
> +               dprintk(vdev, "%s: cannot change default/min/max value\n",
>                         video_device_node_name(vdev));
>                 return -EINVAL;
>         }
> diff --git a/drivers/media/v4l2-core/v4l2-ctrls-core.c b/drivers/media/v4l2-core/v4l2-ctrls-core.c
> index f1486ab032cf..f36d54810dbc 100644
> --- a/drivers/media/v4l2-core/v4l2-ctrls-core.c
> +++ b/drivers/media/v4l2-core/v4l2-ctrls-core.c
> @@ -182,29 +182,69 @@ static void std_init_compound(const struct v4l2_ctrl *ctrl, u32 idx,
>         }
>  }
>
> -void v4l2_ctrl_type_op_init(const struct v4l2_ctrl *ctrl, u32 from_idx,
> +static void std_min_compound(const struct v4l2_ctrl *ctrl, u32 idx,
> +                           union v4l2_ctrl_ptr ptr)
> +{
> +       void *p = ptr.p + idx * ctrl->elem_size;
> +
> +       if (ctrl->p_min.p_const)
> +               memcpy(p, ctrl->p_min.p_const, ctrl->elem_size);
> +       else
> +               memset(p, 0, ctrl->elem_size);
> +}
> +
> +static void std_max_compound(const struct v4l2_ctrl *ctrl, u32 idx,
>                             union v4l2_ctrl_ptr ptr)
> +{
> +       void *p = ptr.p + idx * ctrl->elem_size;
> +
> +       if (ctrl->p_min.p_const)
> +               memcpy(p, ctrl->p_max.p_const, ctrl->elem_size);
> +       else
> +               memset(p, 0, ctrl->elem_size);
> +}
> +
> +static int __v4l2_ctrl_type_op_init(const struct v4l2_ctrl *ctrl, u32 from_idx,
> +                                   u32 which, union v4l2_ctrl_ptr ptr)
>  {
>         unsigned int i;
>         u32 tot_elems = ctrl->elems;
>         u32 elems = tot_elems - from_idx;
> +       s64 value;
>
>         if (from_idx >= tot_elems)
> -               return;
> +               return -EINVAL;
> +
> +       switch (which) {
> +       case V4L2_CTRL_WHICH_DEF_VAL:
> +               value = ctrl->default_value;
> +               break;
> +       case V4L2_CTRL_WHICH_MAX_VAL:
> +               value = ctrl->maximum;
> +               break;
> +       case V4L2_CTRL_WHICH_MIN_VAL:
> +               value = ctrl->minimum;
> +               break;
> +       default:
> +               return -EINVAL;
> +       }
>
>         switch (ctrl->type) {
>         case V4L2_CTRL_TYPE_STRING:
> +               if (which == V4L2_CTRL_WHICH_DEF_VAL)
> +                       value = ctrl->minimum;
> +
>                 for (i = from_idx; i < tot_elems; i++) {
>                         unsigned int offset = i * ctrl->elem_size;
>
> -                       memset(ptr.p_char + offset, ' ', ctrl->minimum);
> -                       ptr.p_char[offset + ctrl->minimum] = '\0';
> +                       memset(ptr.p_char + offset, ' ', value);
> +                       ptr.p_char[offset + value] = '\0';
>                 }
>                 break;
>         case V4L2_CTRL_TYPE_INTEGER64:
> -               if (ctrl->default_value) {
> +               if (value) {
>                         for (i = from_idx; i < tot_elems; i++)
> -                               ptr.p_s64[i] = ctrl->default_value;
> +                               ptr.p_s64[i] = value;
>                 } else {
>                         memset(ptr.p_s64 + from_idx, 0, elems * sizeof(s64));
>                 }
> @@ -214,9 +254,9 @@ void v4l2_ctrl_type_op_init(const struct v4l2_ctrl *ctrl, u32 from_idx,
>         case V4L2_CTRL_TYPE_MENU:
>         case V4L2_CTRL_TYPE_BITMASK:
>         case V4L2_CTRL_TYPE_BOOLEAN:
> -               if (ctrl->default_value) {
> +               if (value) {
>                         for (i = from_idx; i < tot_elems; i++)
> -                               ptr.p_s32[i] = ctrl->default_value;
> +                               ptr.p_s32[i] = value;
>                 } else {
>                         memset(ptr.p_s32 + from_idx, 0, elems * sizeof(s32));
>                 }
> @@ -226,32 +266,63 @@ void v4l2_ctrl_type_op_init(const struct v4l2_ctrl *ctrl, u32 from_idx,
>                 memset(ptr.p_s32 + from_idx, 0, elems * sizeof(s32));
>                 break;
>         case V4L2_CTRL_TYPE_U8:
> -               memset(ptr.p_u8 + from_idx, ctrl->default_value, elems);
> +               memset(ptr.p_u8 + from_idx, value, elems);
>                 break;
>         case V4L2_CTRL_TYPE_U16:
> -               if (ctrl->default_value) {
> +               if (value) {
>                         for (i = from_idx; i < tot_elems; i++)
> -                               ptr.p_u16[i] = ctrl->default_value;
> +                               ptr.p_u16[i] = value;
>                 } else {
>                         memset(ptr.p_u16 + from_idx, 0, elems * sizeof(u16));
>                 }
>                 break;
>         case V4L2_CTRL_TYPE_U32:
> -               if (ctrl->default_value) {
> +               if (value) {
>                         for (i = from_idx; i < tot_elems; i++)
> -                               ptr.p_u32[i] = ctrl->default_value;
> +                               ptr.p_u32[i] = value;
>                 } else {
>                         memset(ptr.p_u32 + from_idx, 0, elems * sizeof(u32));
>                 }
>                 break;
>         default:
> -               for (i = from_idx; i < tot_elems; i++)
> -                       std_init_compound(ctrl, i, ptr);
> +               for (i = from_idx; i < tot_elems; i++) {
> +                       switch (which) {
> +                       case V4L2_CTRL_WHICH_DEF_VAL:
> +                               std_init_compound(ctrl, i, ptr);
> +                               break;
> +                       case V4L2_CTRL_WHICH_MAX_VAL:
> +                               std_max_compound(ctrl, i, ptr);
> +                               break;
> +                       case V4L2_CTRL_WHICH_MIN_VAL:
> +                               std_min_compound(ctrl, i, ptr);
> +                               break;
> +                       }
> +               }
>                 break;
>         }
> +
> +       return 0;
> +}
> +
> +void v4l2_ctrl_type_op_init(const struct v4l2_ctrl *ctrl, u32 from_idx,
> +                           union v4l2_ctrl_ptr ptr)
> +{
> +       __v4l2_ctrl_type_op_init(ctrl, from_idx, V4L2_CTRL_WHICH_DEF_VAL, ptr);
>  }
>  EXPORT_SYMBOL(v4l2_ctrl_type_op_init);
>
> +void v4l2_ctrl_type_op_minimum(const struct v4l2_ctrl *ctrl, u32 from_idx,
> +                              union v4l2_ctrl_ptr ptr)
> +{
> +       __v4l2_ctrl_type_op_init(ctrl, from_idx, V4L2_CTRL_WHICH_MIN_VAL, ptr);
> +}
> +
> +void v4l2_ctrl_type_op_maximum(const struct v4l2_ctrl *ctrl, u32 from_idx,
> +                              union v4l2_ctrl_ptr ptr)
> +{
> +       __v4l2_ctrl_type_op_init(ctrl, from_idx, V4L2_CTRL_WHICH_MAX_VAL, ptr);
> +}
> +
>  void v4l2_ctrl_type_op_log(const struct v4l2_ctrl *ctrl)
>  {
>         union v4l2_ctrl_ptr ptr = ctrl->p_cur;
> @@ -1293,6 +1364,8 @@ EXPORT_SYMBOL(v4l2_ctrl_type_op_validate);
>  static const struct v4l2_ctrl_type_ops std_type_ops = {
>         .equal = v4l2_ctrl_type_op_equal,
>         .init = v4l2_ctrl_type_op_init,
> +       .minimum = v4l2_ctrl_type_op_minimum,
> +       .maximum = v4l2_ctrl_type_op_maximum,
>         .log = v4l2_ctrl_type_op_log,
>         .validate = v4l2_ctrl_type_op_validate,
>  };
> @@ -1764,7 +1837,10 @@ static struct v4l2_ctrl *v4l2_ctrl_new(struct v4l2_ctrl_handler *hdl,
>                         s64 min, s64 max, u64 step, s64 def,
>                         const u32 dims[V4L2_CTRL_MAX_DIMS], u32 elem_size,
>                         u32 flags, const char * const *qmenu,
> -                       const s64 *qmenu_int, const union v4l2_ctrl_ptr p_def,
> +                       const s64 *qmenu_int,
> +                       const union v4l2_ctrl_ptr p_def,
> +                       const union v4l2_ctrl_ptr p_min,
> +                       const union v4l2_ctrl_ptr p_max,
>                         void *priv)
>  {
>         struct v4l2_ctrl *ctrl;
> @@ -1888,6 +1964,12 @@ static struct v4l2_ctrl *v4l2_ctrl_new(struct v4l2_ctrl_handler *hdl,
>                 break;
>         }
>
> +       if (type < V4L2_CTRL_COMPOUND_TYPES &&
> +           type != V4L2_CTRL_TYPE_BUTTON &&
> +           type != V4L2_CTRL_TYPE_CTRL_CLASS &&
> +           type != V4L2_CTRL_TYPE_STRING)
> +               flags |= V4L2_CTRL_FLAG_HAS_WHICH_MIN_MAX;
> +
>         /* Sanity checks */
>         if (id == 0 || name == NULL || !elem_size ||
>             id >= V4L2_CID_PRIVATE_BASE ||
> @@ -1896,6 +1978,21 @@ static struct v4l2_ctrl *v4l2_ctrl_new(struct v4l2_ctrl_handler *hdl,
>                 handler_set_err(hdl, -ERANGE);
>                 return NULL;
>         }
> +
> +       if ((!p_def.p_const && p_min.p_const) ||
> +           (p_min.p_const && !p_max.p_const) ||
> +           (!p_min.p_const && p_max.p_const)) {
> +               handler_set_err(hdl, -EINVAL);
> +               return NULL;
> +       }
> +
> +       if (flags & V4L2_CTRL_FLAG_HAS_WHICH_MIN_MAX &&
> +           type >= V4L2_CTRL_COMPOUND_TYPES &&
> +           (!p_min.p_const || !p_max.p_const)) {
> +               handler_set_err(hdl, -EINVAL);
> +               return NULL;
> +       }
> +
>         err = check_range(type, min, max, step, def);
>         if (err) {
>                 handler_set_err(hdl, err);
> @@ -1937,6 +2034,8 @@ static struct v4l2_ctrl *v4l2_ctrl_new(struct v4l2_ctrl_handler *hdl,
>
>         if (type >= V4L2_CTRL_COMPOUND_TYPES && p_def.p_const)
>                 sz_extra += elem_size;
> +       if (type >= V4L2_CTRL_COMPOUND_TYPES && p_min.p_const)
> +               sz_extra += elem_size * 2;
>
>         ctrl = kvzalloc(sizeof(*ctrl) + sz_extra, GFP_KERNEL);
>         if (ctrl == NULL) {
> @@ -2002,6 +2101,14 @@ static struct v4l2_ctrl *v4l2_ctrl_new(struct v4l2_ctrl_handler *hdl,
>                 memcpy(ctrl->p_def.p, p_def.p_const, elem_size);
>         }
>
> +       if (flags & V4L2_CTRL_FLAG_HAS_WHICH_MIN_MAX &&
> +           p_min.p_const && p_max.p_const) {
> +               ctrl->p_min.p = ctrl->p_def.p + elem_size;
> +               memcpy(ctrl->p_min.p, p_min.p_const, elem_size);
> +               ctrl->p_max.p = ctrl->p_min.p + elem_size;
> +               memcpy(ctrl->p_max.p, p_max.p_const, elem_size);
> +       }
> +
>         ctrl->type_ops->init(ctrl, 0, ctrl->p_cur);
>         cur_to_new(ctrl);
>
> @@ -2052,7 +2159,8 @@ struct v4l2_ctrl *v4l2_ctrl_new_custom(struct v4l2_ctrl_handler *hdl,
>                         type, min, max,
>                         is_menu ? cfg->menu_skip_mask : step, def,
>                         cfg->dims, cfg->elem_size,
> -                       flags, qmenu, qmenu_int, cfg->p_def, priv);
> +                       flags, qmenu, qmenu_int, cfg->p_def, cfg->p_min,
> +                       cfg->p_max, priv);
>         if (ctrl)
>                 ctrl->is_private = cfg->is_private;
>         return ctrl;
> @@ -2077,7 +2185,8 @@ struct v4l2_ctrl *v4l2_ctrl_new_std(struct v4l2_ctrl_handler *hdl,
>         }
>         return v4l2_ctrl_new(hdl, ops, NULL, id, name, type,
>                              min, max, step, def, NULL, 0,
> -                            flags, NULL, NULL, ptr_null, NULL);
> +                            flags, NULL, NULL, ptr_null, ptr_null,
> +                            ptr_null, NULL);
>  }
>  EXPORT_SYMBOL(v4l2_ctrl_new_std);
>
> @@ -2110,7 +2219,8 @@ struct v4l2_ctrl *v4l2_ctrl_new_std_menu(struct v4l2_ctrl_handler *hdl,
>         }
>         return v4l2_ctrl_new(hdl, ops, NULL, id, name, type,
>                              0, max, mask, def, NULL, 0,
> -                            flags, qmenu, qmenu_int, ptr_null, NULL);
> +                            flags, qmenu, qmenu_int, ptr_null, ptr_null,
> +                            ptr_null, NULL);
>  }
>  EXPORT_SYMBOL(v4l2_ctrl_new_std_menu);
>
> @@ -2142,7 +2252,8 @@ struct v4l2_ctrl *v4l2_ctrl_new_std_menu_items(struct v4l2_ctrl_handler *hdl,
>         }
>         return v4l2_ctrl_new(hdl, ops, NULL, id, name, type,
>                              0, max, mask, def, NULL, 0,
> -                            flags, qmenu, NULL, ptr_null, NULL);
> +                            flags, qmenu, NULL, ptr_null, ptr_null,
> +                            ptr_null, NULL);
>
>  }
>  EXPORT_SYMBOL(v4l2_ctrl_new_std_menu_items);
> @@ -2150,7 +2261,9 @@ EXPORT_SYMBOL(v4l2_ctrl_new_std_menu_items);
>  /* Helper function for standard compound controls */
>  struct v4l2_ctrl *v4l2_ctrl_new_std_compound(struct v4l2_ctrl_handler *hdl,
>                                 const struct v4l2_ctrl_ops *ops, u32 id,
> -                               const union v4l2_ctrl_ptr p_def)
> +                               const union v4l2_ctrl_ptr p_def,
> +                               const union v4l2_ctrl_ptr p_min,
> +                               const union v4l2_ctrl_ptr p_max)
>  {
>         const char *name;
>         enum v4l2_ctrl_type type;
> @@ -2164,7 +2277,7 @@ struct v4l2_ctrl *v4l2_ctrl_new_std_compound(struct v4l2_ctrl_handler *hdl,
>         }
>         return v4l2_ctrl_new(hdl, ops, NULL, id, name, type,
>                              min, max, step, def, NULL, 0,
> -                            flags, NULL, NULL, p_def, NULL);
> +                            flags, NULL, NULL, p_def, p_min, p_max, NULL);
>  }
>  EXPORT_SYMBOL(v4l2_ctrl_new_std_compound);
>
> @@ -2188,7 +2301,8 @@ struct v4l2_ctrl *v4l2_ctrl_new_int_menu(struct v4l2_ctrl_handler *hdl,
>         }
>         return v4l2_ctrl_new(hdl, ops, NULL, id, name, type,
>                              0, max, 0, def, NULL, 0,
> -                            flags, NULL, qmenu_int, ptr_null, NULL);
> +                            flags, NULL, qmenu_int, ptr_null, ptr_null,
> +                            ptr_null, NULL);
>  }
>  EXPORT_SYMBOL(v4l2_ctrl_new_int_menu);
>
> diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
> index 01ba27f2ef87..aaf68bfaa601 100644
> --- a/drivers/media/v4l2-core/v4l2-ioctl.c
> +++ b/drivers/media/v4l2-core/v4l2-ioctl.c
> @@ -884,7 +884,9 @@ static bool check_ext_ctrls(struct v4l2_ext_controls *c, unsigned long ioctl)
>                         return false;
>                 break;
>         case V4L2_CTRL_WHICH_DEF_VAL:
> -               /* Default value cannot be changed */
> +       case V4L2_CTRL_WHICH_MIN_VAL:
> +       case V4L2_CTRL_WHICH_MAX_VAL:
> +               /* Default, minimum or maximum value cannot be changed */
>                 if (ioctl == VIDIOC_S_EXT_CTRLS ||
>                     ioctl == VIDIOC_TRY_EXT_CTRLS) {
>                         c->error_idx = c->count;
> diff --git a/include/media/v4l2-ctrls.h b/include/media/v4l2-ctrls.h
> index b0db167a3ac4..6e12493b30d3 100644
> --- a/include/media/v4l2-ctrls.h
> +++ b/include/media/v4l2-ctrls.h
> @@ -133,6 +133,8 @@ struct v4l2_ctrl_ops {
>   *
>   * @equal: return true if all ctrl->elems array elements are equal.
>   * @init: initialize the value for array elements from from_idx to ctrl->elems.
> + * @minimum: set the value to the minimum value of the control.
> + * @maximum: set the value to the maximum value of the control.
>   * @log: log the value.
>   * @validate: validate the value for ctrl->new_elems array elements.
>   *     Return 0 on success and a negative value otherwise.
> @@ -142,6 +144,10 @@ struct v4l2_ctrl_type_ops {
>                       union v4l2_ctrl_ptr ptr1, union v4l2_ctrl_ptr ptr2);
>         void (*init)(const struct v4l2_ctrl *ctrl, u32 from_idx,
>                      union v4l2_ctrl_ptr ptr);
> +       void (*minimum)(const struct v4l2_ctrl *ctrl, u32 idx,
> +                       union v4l2_ctrl_ptr ptr);
> +       void (*maximum)(const struct v4l2_ctrl *ctrl, u32 idx,
> +                       union v4l2_ctrl_ptr ptr);
>         void (*log)(const struct v4l2_ctrl *ctrl);
>         int (*validate)(const struct v4l2_ctrl *ctrl, union v4l2_ctrl_ptr ptr);
>  };
> @@ -247,6 +253,12 @@ typedef void (*v4l2_ctrl_notify_fnc)(struct v4l2_ctrl *ctrl, void *priv);
>   * @p_def:     The control's default value represented via a union which
>   *             provides a standard way of accessing control types
>   *             through a pointer (for compound controls only).
> + * @p_min:     The control's minimum value represented via a union which
> + *             provides a standard way of accessing control types
> + *             through a pointer (for compound controls only).
> + * @p_max:     The control's maximum value represented via a union which
> + *             provides a standard way of accessing control types
> + *             through a pointer (for compound controls only).
>   * @p_cur:     The control's current value represented via a union which
>   *             provides a standard way of accessing control types
>   *             through a pointer.
> @@ -306,6 +318,8 @@ struct v4l2_ctrl {
>         } cur;
>
>         union v4l2_ctrl_ptr p_def;
> +       union v4l2_ctrl_ptr p_min;
> +       union v4l2_ctrl_ptr p_max;
>         union v4l2_ctrl_ptr p_new;
>         union v4l2_ctrl_ptr p_cur;
>  };
> @@ -425,6 +439,8 @@ struct v4l2_ctrl_handler {
>   * @step:      The control's step value for non-menu controls.
>   * @def:       The control's default value.
>   * @p_def:     The control's default value for compound controls.
> + * @p_min:     The control's minimum value for compound controls.
> + * @p_max:     The control's maximum value for compound controls.
>   * @dims:      The size of each dimension.
>   * @elem_size: The size in bytes of the control.
>   * @flags:     The control's flags.
> @@ -454,6 +470,8 @@ struct v4l2_ctrl_config {
>         u64 step;
>         s64 def;
>         union v4l2_ctrl_ptr p_def;
> +       union v4l2_ctrl_ptr p_min;
> +       union v4l2_ctrl_ptr p_max;
>         u32 dims[V4L2_CTRL_MAX_DIMS];
>         u32 elem_size;
>         u32 flags;
> @@ -723,17 +741,23 @@ struct v4l2_ctrl *v4l2_ctrl_new_std_menu_items(struct v4l2_ctrl_handler *hdl,
>   * @ops:       The control ops.
>   * @id:        The control ID.
>   * @p_def:     The control's default value.
> + * @p_min:     The control's minimum value.
> + * @p_max:     The control's maximum value.
>   *
> - * Sames as v4l2_ctrl_new_std(), but with support to compound controls, thanks
> - * to the @p_def field. Use v4l2_ctrl_ptr_create() to create @p_def from a
> - * pointer. Use v4l2_ctrl_ptr_create(NULL) if the default value of the
> - * compound control should be all zeroes.
> + * Same as v4l2_ctrl_new_std(), but with support to compound controls, thanks
> + * to the @p_def/min/max fields. Use v4l2_ctrl_ptr_create() to create
> + * @p_def/min/max from a pointer. Use v4l2_ctrl_ptr_create(NULL) if the
> + * default value of the compound control should be all zeroes. Use
> + * v4l2_ctrl_ptr_create(NULL) if the min/max value of the compound control
> + * is not defined, -ENODATA will be returned in this case.
>   *
>   */
>  struct v4l2_ctrl *v4l2_ctrl_new_std_compound(struct v4l2_ctrl_handler *hdl,
>                                              const struct v4l2_ctrl_ops *ops,
>                                              u32 id,
> -                                            const union v4l2_ctrl_ptr p_def);
> +                                            const union v4l2_ctrl_ptr p_def,
> +                                            const union v4l2_ctrl_ptr p_min,
> +                                            const union v4l2_ctrl_ptr p_max);
>
>  /**
>   * v4l2_ctrl_new_int_menu() - Create a new standard V4L2 integer menu control.
> diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
> index 089d553cf736..d7670aaf3b5f 100644
> --- a/include/uapi/linux/videodev2.h
> +++ b/include/uapi/linux/videodev2.h
> @@ -1863,6 +1863,8 @@ struct v4l2_ext_controls {
>  #define V4L2_CTRL_WHICH_CUR_VAL   0
>  #define V4L2_CTRL_WHICH_DEF_VAL   0x0f000000
>  #define V4L2_CTRL_WHICH_REQUEST_VAL 0x0f010000
> +#define V4L2_CTRL_WHICH_MIN_VAL   0x0f020000
> +#define V4L2_CTRL_WHICH_MAX_VAL   0x0f030000
>
>  enum v4l2_ctrl_type {
>         V4L2_CTRL_TYPE_INTEGER       = 1,
> @@ -1970,6 +1972,7 @@ struct v4l2_querymenu {
>  #define V4L2_CTRL_FLAG_EXECUTE_ON_WRITE        0x0200
>  #define V4L2_CTRL_FLAG_MODIFY_LAYOUT   0x0400
>  #define V4L2_CTRL_FLAG_DYNAMIC_ARRAY   0x0800
> +#define V4L2_CTRL_FLAG_HAS_WHICH_MIN_MAX 0x1000
>
>  /*  Query flags, to be ORed with the control ID */
>  #define V4L2_CTRL_FLAG_NEXT_CTRL       0x80000000
> --
> 2.41.0.694.ge786442a9b-goog
>
Yunke Cao Sept. 15, 2023, 7:28 a.m. UTC | #2
Thanks Hans!

These make sense. I will address them in the next version.


On Wed, Sep 13, 2023 at 6:26 PM Hans Verkuil <hverkuil-cisco@xs4all.nl> wrote:
>
> Hi Yunke,
>
> Thank you for the reminder! Since this series is for uvc, I tend to forget that
> it contains a single patch for the V4L2 core that I need to review. Just email
> me a reminder for v13 if you don't see a review after a week.
>
> On 17/08/2023 09:17, Yunke Cao wrote:
> > From: Hans Verkuil <hverkuil-cisco@xs4all.nl>
> >
> > Add the capability of retrieving the min and max values of a
> > compound control.
> >
> > Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
> > Signed-off-by: Yunke Cao <yunkec@google.com>
> > ---
> > Changelog since v11:
> > - Added a flag V4L2_CTRL_FLAG_HAS_WHICH_MIN_MAX.
> > - Modified std_min/max_compound() to be void function. Moved the check of
> >   whether WHICH_MIN/MAX_VAL into prepare_ext_ctrls(), and return EINVAL.
> > - Modified documentations to reflect this change.
> > Changelog since v10:
> > - No change.
> > Changelog since v9:
> > - No change.
> > Changelog since v8:
> > - Return ENODATA when min/max is not implemented. Document this behavior.
> > - Created a shared helper function __v4l2_ctrl_type_op_init that takes "which"
> >   as a parameter. Call it in def, min and max operations.
> > Changelog since v7:
> > - Document that the definition of the min/max are provided by compound controls
> >   are defined in control documentation.
> > - Return error, instead of zeroed memory for v4l2_ctrl_ptr_create(NULL).
> >
> > git am from https://lore.kernel.org/all/20191119113457.57833-3-hverkuil-cisco@xs4all.nl/
> > - Fixed some merge conflits.
> > - Fixed the build error in drivers/media/platform/qcom/venus.
> >
> >  .../media/v4l/vidioc-g-ext-ctrls.rst          |  16 +-
> >  .../media/v4l/vidioc-queryctrl.rst            |   9 +-
> >  .../media/videodev2.h.rst.exceptions          |   3 +
> >  drivers/media/i2c/imx214.c                    |   5 +-
> >  .../media/platform/qcom/venus/venc_ctrls.c    |   9 +-
> >  drivers/media/v4l2-core/v4l2-ctrls-api.c      |  54 ++++--
> >  drivers/media/v4l2-core/v4l2-ctrls-core.c     | 160 +++++++++++++++---
> >  drivers/media/v4l2-core/v4l2-ioctl.c          |   4 +-
> >  include/media/v4l2-ctrls.h                    |  34 +++-
> >  include/uapi/linux/videodev2.h                |   3 +
> >  10 files changed, 252 insertions(+), 45 deletions(-)
> >
> > diff --git a/Documentation/userspace-api/media/v4l/vidioc-g-ext-ctrls.rst b/Documentation/userspace-api/media/v4l/vidioc-g-ext-ctrls.rst
> > index 7b1001d11f9c..b4bf016411d3 100644
> > --- a/Documentation/userspace-api/media/v4l/vidioc-g-ext-ctrls.rst
> > +++ b/Documentation/userspace-api/media/v4l/vidioc-g-ext-ctrls.rst
> > @@ -330,14 +330,26 @@ still cause this situation.
> >        - Which value of the control to get/set/try.
> >      * - :cspan:`2` ``V4L2_CTRL_WHICH_CUR_VAL`` will return the current value of
> >       the control, ``V4L2_CTRL_WHICH_DEF_VAL`` will return the default
> > +     value of the control, ``V4L2_CTRL_WHICH_MIN_VAL`` will return the minimum
> > +     value of the control, ``V4L2_CTRL_WHICH_MAX_VAL`` will return the maximum
> >       value of the control and ``V4L2_CTRL_WHICH_REQUEST_VAL`` indicates that
> >       these controls have to be retrieved from a request or tried/set for
> >       a request. In the latter case the ``request_fd`` field contains the
>
> This text is getting a bit messy. I propose this instead:
>
>     * - :cspan:`2` ``V4L2_CTRL_WHICH_CUR_VAL`` will return the current value of
>         the control, ``V4L2_CTRL_WHICH_DEF_VAL`` will return the default
>         value of the control, ``V4L2_CTRL_WHICH_MIN_VAL`` will return the minimum
>         value of the control, and ``V4L2_CTRL_WHICH_MAX_VAL`` will return the maximum
>         value of the control. ``V4L2_CTRL_WHICH_REQUEST_VAL`` indicates that
>         the control value has to be retrieved from a request or tried/set for
>         a request. In that case the ``request_fd`` field contains the
>
> It's just a few minor changes, but it makes it easier to read.
>
> >       file descriptor of the request that should be used. If the device
> >       does not support requests, then ``EACCES`` will be returned.
> >
> > -     When using ``V4L2_CTRL_WHICH_DEF_VAL`` be aware that you can only
> > -     get the default value of the control, you cannot set or try it.
> > +     When using ``V4L2_CTRL_WHICH_DEF_VAL``, ``V4L2_CTRL_WHICH_MIN_VAL``
> > +     or ``V4L2_CTRL_WHICH_MAX_VAL`` be aware that you can only get the
> > +     default/minimum/maximum value of the control, you cannot set or try it.
> > +
> > +     Whether a control supports querying the minimum and maximum values using
> > +     ``V4L2_CTRL_WHICH_MIN_VAL`` and ``V4L2_CTRL_WHICH_MAX_VAL`` is indicated
> > +     by the ``V4L2_CTRL_FLAG_HAS_WHICH_MIN_MAX`` flag. Most non-compound
> > +     control types support this. For controls with compound types, the
> > +     definition of minimum/maximum values are provided by
> > +     the control documentation. If a compound control does not document the
> > +     meaning of minimum/maximum value, then querying the minimum or maximum
> > +     value will result in the error code -EINVAL.
> >
> >       For backwards compatibility you can also use a control class here
> >       (see :ref:`ctrl-class`). In that case all controls have to
> > diff --git a/Documentation/userspace-api/media/v4l/vidioc-queryctrl.rst b/Documentation/userspace-api/media/v4l/vidioc-queryctrl.rst
> > index 56d5c8b0b88b..b39f7e27bbbe 100644
> > --- a/Documentation/userspace-api/media/v4l/vidioc-queryctrl.rst
> > +++ b/Documentation/userspace-api/media/v4l/vidioc-queryctrl.rst
> > @@ -447,7 +447,10 @@ See also the examples in :ref:`control`.
> >        - n/a
> >        - A struct :c:type:`v4l2_rect`, containing a rectangle described by
> >       the position of its top-left corner, the width and the height. Units
> > -     depend on the use case.
> > +     depend on the use case. Support for ``V4L2_CTRL_WHICH_MIN_VAL`` and
> > +     ``V4L2_CTRL_WHICH_MAX_VAL`` is optional and depends on the
> > +     ``V4L2_CTRL_FLAG_HAS_WHICH_MIN_MAX`` flag. See the documentation of
> > +     the specific control on how to interpret the minimum and maximum values.
> >      * - ``V4L2_CTRL_TYPE_H264_SPS``
> >        - n/a
> >        - n/a
> > @@ -664,6 +667,10 @@ See also the examples in :ref:`control`.
> >       ``dims[0]``. So setting the control with a differently sized
> >       array will change the ``elems`` field when the control is
> >       queried afterwards.
> > +    * - ``V4L2_CTRL_FLAG_HAS_WHICH_MIN_MAX``
> > +      - 0x1000
> > +      - This control supports getting minimum and maximum values using
> > +      vidioc_g_ext_ctrls with V4L2_CTRL_WHICH_MIN/MAX_VAL.
> >
> >  Return Value
> >  ============
> > diff --git a/Documentation/userspace-api/media/videodev2.h.rst.exceptions b/Documentation/userspace-api/media/videodev2.h.rst.exceptions
> > index c46082ef0e4d..a417af25e9a4 100644
> > --- a/Documentation/userspace-api/media/videodev2.h.rst.exceptions
> > +++ b/Documentation/userspace-api/media/videodev2.h.rst.exceptions
> > @@ -393,6 +393,7 @@ replace define V4L2_CTRL_FLAG_HAS_PAYLOAD control-flags
> >  replace define V4L2_CTRL_FLAG_EXECUTE_ON_WRITE control-flags
> >  replace define V4L2_CTRL_FLAG_MODIFY_LAYOUT control-flags
> >  replace define V4L2_CTRL_FLAG_DYNAMIC_ARRAY control-flags
> > +replace define V4L2_CTRL_FLAG_HAS_WHICH_MIN_MAX control-flags
> >
> >  replace define V4L2_CTRL_FLAG_NEXT_CTRL control
> >  replace define V4L2_CTRL_FLAG_NEXT_COMPOUND control
> > @@ -567,6 +568,8 @@ ignore define V4L2_CTRL_DRIVER_PRIV
> >  ignore define V4L2_CTRL_MAX_DIMS
> >  ignore define V4L2_CTRL_WHICH_CUR_VAL
> >  ignore define V4L2_CTRL_WHICH_DEF_VAL
> > +ignore define V4L2_CTRL_WHICH_MIN_VAL
> > +ignore define V4L2_CTRL_WHICH_MAX_VAL
> >  ignore define V4L2_CTRL_WHICH_REQUEST_VAL
> >  ignore define V4L2_OUT_CAP_CUSTOM_TIMINGS
> >  ignore define V4L2_CID_MAX_CTRLS
> > diff --git a/drivers/media/i2c/imx214.c b/drivers/media/i2c/imx214.c
> > index 2f9c8582f940..8db4a5eb1737 100644
> > --- a/drivers/media/i2c/imx214.c
> > +++ b/drivers/media/i2c/imx214.c
> > @@ -1037,7 +1037,10 @@ static int imx214_probe(struct i2c_client *client)
> >       imx214->unit_size = v4l2_ctrl_new_std_compound(&imx214->ctrls,
> >                               NULL,
> >                               V4L2_CID_UNIT_CELL_SIZE,
> > -                             v4l2_ctrl_ptr_create((void *)&unit_size));
> > +                             v4l2_ctrl_ptr_create((void *)&unit_size),
> > +                             v4l2_ctrl_ptr_create(NULL),
> > +                             v4l2_ctrl_ptr_create(NULL));
> > +
> >       ret = imx214->ctrls.error;
> >       if (ret) {
> >               dev_err(&client->dev, "%s control init failed (%d)\n",
> > diff --git a/drivers/media/platform/qcom/venus/venc_ctrls.c b/drivers/media/platform/qcom/venus/venc_ctrls.c
> > index 7468e43800a9..28eca8f9d148 100644
> > --- a/drivers/media/platform/qcom/venus/venc_ctrls.c
> > +++ b/drivers/media/platform/qcom/venus/venc_ctrls.c
> > @@ -607,11 +607,16 @@ int venc_ctrl_init(struct venus_inst *inst)
> >
> >       v4l2_ctrl_new_std_compound(&inst->ctrl_handler, &venc_ctrl_ops,
> >                                  V4L2_CID_COLORIMETRY_HDR10_CLL_INFO,
> > -                                v4l2_ctrl_ptr_create(&p_hdr10_cll));
> > +                                v4l2_ctrl_ptr_create(&p_hdr10_cll),
> > +                                v4l2_ctrl_ptr_create(NULL),
> > +                                v4l2_ctrl_ptr_create(NULL));
> >
> >       v4l2_ctrl_new_std_compound(&inst->ctrl_handler, &venc_ctrl_ops,
> >                                  V4L2_CID_COLORIMETRY_HDR10_MASTERING_DISPLAY,
> > -                                v4l2_ctrl_ptr_create((void *)&p_hdr10_mastering));
> > +                                v4l2_ctrl_ptr_create((void *)&p_hdr10_mastering),
> > +                                v4l2_ctrl_ptr_create(NULL),
> > +                                v4l2_ctrl_ptr_create(NULL));
> > +
> >
> >       v4l2_ctrl_new_std_menu(&inst->ctrl_handler, &venc_ctrl_ops,
> >                              V4L2_CID_MPEG_VIDEO_INTRA_REFRESH_PERIOD_TYPE,
> > diff --git a/drivers/media/v4l2-core/v4l2-ctrls-api.c b/drivers/media/v4l2-core/v4l2-ctrls-api.c
> > index 002ea6588edf..d022e1ed4835 100644
> > --- a/drivers/media/v4l2-core/v4l2-ctrls-api.c
> > +++ b/drivers/media/v4l2-core/v4l2-ctrls-api.c
> > @@ -94,6 +94,22 @@ static int def_to_user(struct v4l2_ext_control *c, struct v4l2_ctrl *ctrl)
> >       return ptr_to_user(c, ctrl, ctrl->p_new);
> >  }
> >
> > +/* Helper function: copy the minimum control value back to the caller */
> > +static int min_to_user(struct v4l2_ext_control *c, struct v4l2_ctrl *ctrl)
> > +{
> > +     ctrl->type_ops->minimum(ctrl, 0, ctrl->p_new);
> > +
> > +     return ptr_to_user(c, ctrl, ctrl->p_new);
> > +}
> > +
> > +/* Helper function: copy the maximum control value back to the caller */
> > +static int max_to_user(struct v4l2_ext_control *c, struct v4l2_ctrl *ctrl)
> > +{
> > +     ctrl->type_ops->maximum(ctrl, 0, ctrl->p_new);
> > +
> > +     return ptr_to_user(c, ctrl, ctrl->p_new);
> > +}
> > +
> >  /* Helper function: copy the caller-provider value as the new control value */
> >  static int user_to_new(struct v4l2_ext_control *c, struct v4l2_ctrl *ctrl)
> >  {
> > @@ -229,8 +245,8 @@ static int prepare_ext_ctrls(struct v4l2_ctrl_handler *hdl,
> >               cs->error_idx = i;
> >
> >               if (cs->which &&
> > -                 cs->which != V4L2_CTRL_WHICH_DEF_VAL &&
> > -                 cs->which != V4L2_CTRL_WHICH_REQUEST_VAL &&
> > +                 (cs->which < V4L2_CTRL_WHICH_DEF_VAL ||
> > +                  cs->which > V4L2_CTRL_WHICH_MAX_VAL) &&
> >                   V4L2_CTRL_ID2WHICH(id) != cs->which) {
> >                       dprintk(vdev,
> >                               "invalid which 0x%x or control id 0x%x\n",
> > @@ -259,6 +275,15 @@ static int prepare_ext_ctrls(struct v4l2_ctrl_handler *hdl,
> >                       return -EINVAL;
> >               }
> >
> > +             if (!(ctrl->flags & V4L2_CTRL_FLAG_HAS_WHICH_MIN_MAX) &&
> > +                 (cs->which == V4L2_CTRL_WHICH_MIN_VAL ||
> > +                  cs->which == V4L2_CTRL_WHICH_MAX_VAL)) {
> > +                     dprintk(vdev,
> > +                             "invalid which 0x%x or control id 0x%x\n",
> > +                             cs->which, id);
> > +                     return -EINVAL;
> > +             }
> > +
> >               if (ctrl->cluster[0]->ncontrols > 1)
> >                       have_clusters = true;
> >               if (ctrl->cluster[0] != ctrl)
> > @@ -368,8 +393,8 @@ static int prepare_ext_ctrls(struct v4l2_ctrl_handler *hdl,
> >   */
> >  static int class_check(struct v4l2_ctrl_handler *hdl, u32 which)
> >  {
> > -     if (which == 0 || which == V4L2_CTRL_WHICH_DEF_VAL ||
> > -         which == V4L2_CTRL_WHICH_REQUEST_VAL)
> > +     if (which == 0 || (which >= V4L2_CTRL_WHICH_DEF_VAL &&
> > +                        which <= V4L2_CTRL_WHICH_MAX_VAL))
> >               return 0;
> >       return find_ref_lock(hdl, which | 1) ? 0 : -EINVAL;
> >  }
> > @@ -389,10 +414,12 @@ int v4l2_g_ext_ctrls_common(struct v4l2_ctrl_handler *hdl,
> >       struct v4l2_ctrl_helper *helpers = helper;
> >       int ret;
> >       int i, j;
> > -     bool is_default, is_request;
> > +     bool is_default, is_request, is_min, is_max;
> >
> >       is_default = (cs->which == V4L2_CTRL_WHICH_DEF_VAL);
> >       is_request = (cs->which == V4L2_CTRL_WHICH_REQUEST_VAL);
> > +     is_min = (cs->which == V4L2_CTRL_WHICH_MIN_VAL);
> > +     is_max = (cs->which == V4L2_CTRL_WHICH_MAX_VAL);
> >
> >       cs->error_idx = cs->count;
> >       cs->which = V4L2_CTRL_ID2WHICH(cs->which);
> > @@ -432,13 +459,14 @@ int v4l2_g_ext_ctrls_common(struct v4l2_ctrl_handler *hdl,
> >
> >               /*
> >                * g_volatile_ctrl will update the new control values.
> > -              * This makes no sense for V4L2_CTRL_WHICH_DEF_VAL and
> > +              * This makes no sense for V4L2_CTRL_WHICH_DEF_VAL,
> > +              * V4L2_CTRL_WHICH_MIN_VAL, V4L2_CTRL_WHICH_MAX_VAL and
> >                * V4L2_CTRL_WHICH_REQUEST_VAL. In the case of requests
> >                * it is v4l2_ctrl_request_complete() that copies the
> >                * volatile controls at the time of request completion
> >                * to the request, so you don't want to do that again.
> >                */
> > -             if (!is_default && !is_request &&
> > +             if (!is_default && !is_request && !is_min && !is_max &&
> >                   ((master->flags & V4L2_CTRL_FLAG_VOLATILE) ||
> >                   (master->has_volatiles && !is_cur_manual(master)))) {
> >                       for (j = 0; j < master->ncontrols; j++)
> > @@ -467,6 +495,10 @@ int v4l2_g_ext_ctrls_common(struct v4l2_ctrl_handler *hdl,
> >                               ret = -ENOMEM;
> >                       else if (is_request && ref->p_req_valid)
> >                               ret = req_to_user(cs->controls + idx, ref);
> > +                     else if (is_min)
> > +                             ret = min_to_user(cs->controls + idx, ref->ctrl);
> > +                     else if (is_max)
> > +                             ret = max_to_user(cs->controls + idx, ref->ctrl);
> >                       else if (is_volatile)
> >                               ret = new_to_user(cs->controls + idx, ref->ctrl);
> >                       else
> > @@ -564,9 +596,11 @@ int try_set_ext_ctrls_common(struct v4l2_fh *fh,
> >
> >       cs->error_idx = cs->count;
> >
> > -     /* Default value cannot be changed */
> > -     if (cs->which == V4L2_CTRL_WHICH_DEF_VAL) {
> > -             dprintk(vdev, "%s: cannot change default value\n",
> > +     /* Default/minimum/maximum values cannot be changed */
> > +     if (cs->which == V4L2_CTRL_WHICH_DEF_VAL ||
> > +         cs->which == V4L2_CTRL_WHICH_MIN_VAL ||
> > +         cs->which == V4L2_CTRL_WHICH_MAX_VAL) {
> > +             dprintk(vdev, "%s: cannot change default/min/max value\n",
> >                       video_device_node_name(vdev));
> >               return -EINVAL;
> >       }
> > diff --git a/drivers/media/v4l2-core/v4l2-ctrls-core.c b/drivers/media/v4l2-core/v4l2-ctrls-core.c
> > index f1486ab032cf..f36d54810dbc 100644
> > --- a/drivers/media/v4l2-core/v4l2-ctrls-core.c
> > +++ b/drivers/media/v4l2-core/v4l2-ctrls-core.c
> > @@ -182,29 +182,69 @@ static void std_init_compound(const struct v4l2_ctrl *ctrl, u32 idx,
> >       }
> >  }
> >
> > -void v4l2_ctrl_type_op_init(const struct v4l2_ctrl *ctrl, u32 from_idx,
> > +static void std_min_compound(const struct v4l2_ctrl *ctrl, u32 idx,
> > +                         union v4l2_ctrl_ptr ptr)
> > +{
> > +     void *p = ptr.p + idx * ctrl->elem_size;
> > +
> > +     if (ctrl->p_min.p_const)
> > +             memcpy(p, ctrl->p_min.p_const, ctrl->elem_size);
> > +     else
> > +             memset(p, 0, ctrl->elem_size);
> > +}
> > +
> > +static void std_max_compound(const struct v4l2_ctrl *ctrl, u32 idx,
> >                           union v4l2_ctrl_ptr ptr)
> > +{
> > +     void *p = ptr.p + idx * ctrl->elem_size;
> > +
> > +     if (ctrl->p_min.p_const)
>
> Typo: p_min -> p_max
>
> > +             memcpy(p, ctrl->p_max.p_const, ctrl->elem_size);
> > +     else
> > +             memset(p, 0, ctrl->elem_size);
> > +}
> > +
> > +static int __v4l2_ctrl_type_op_init(const struct v4l2_ctrl *ctrl, u32 from_idx,
>
> Just keep this as a void function. The return value is never used anyway.
>
> The assumption is that this function is only called with valid arguments.
>
> > +                                 u32 which, union v4l2_ctrl_ptr ptr)
> >  {
> >       unsigned int i;
> >       u32 tot_elems = ctrl->elems;
> >       u32 elems = tot_elems - from_idx;
> > +     s64 value;
> >
> >       if (from_idx >= tot_elems)
> > -             return;
> > +             return -EINVAL;
> > +
> > +     switch (which) {
> > +     case V4L2_CTRL_WHICH_DEF_VAL:
> > +             value = ctrl->default_value;
> > +             break;
> > +     case V4L2_CTRL_WHICH_MAX_VAL:
> > +             value = ctrl->maximum;
> > +             break;
> > +     case V4L2_CTRL_WHICH_MIN_VAL:
> > +             value = ctrl->minimum;
> > +             break;
> > +     default:
> > +             return -EINVAL;
> > +     }
> >
> >       switch (ctrl->type) {
> >       case V4L2_CTRL_TYPE_STRING:
> > +             if (which == V4L2_CTRL_WHICH_DEF_VAL)
> > +                     value = ctrl->minimum;
> > +
> >               for (i = from_idx; i < tot_elems; i++) {
> >                       unsigned int offset = i * ctrl->elem_size;
> >
> > -                     memset(ptr.p_char + offset, ' ', ctrl->minimum);
> > -                     ptr.p_char[offset + ctrl->minimum] = '\0';
> > +                     memset(ptr.p_char + offset, ' ', value);
> > +                     ptr.p_char[offset + value] = '\0';
> >               }
> >               break;
> >       case V4L2_CTRL_TYPE_INTEGER64:
> > -             if (ctrl->default_value) {
> > +             if (value) {
> >                       for (i = from_idx; i < tot_elems; i++)
> > -                             ptr.p_s64[i] = ctrl->default_value;
> > +                             ptr.p_s64[i] = value;
> >               } else {
> >                       memset(ptr.p_s64 + from_idx, 0, elems * sizeof(s64));
> >               }
> > @@ -214,9 +254,9 @@ void v4l2_ctrl_type_op_init(const struct v4l2_ctrl *ctrl, u32 from_idx,
> >       case V4L2_CTRL_TYPE_MENU:
> >       case V4L2_CTRL_TYPE_BITMASK:
> >       case V4L2_CTRL_TYPE_BOOLEAN:
> > -             if (ctrl->default_value) {
> > +             if (value) {
> >                       for (i = from_idx; i < tot_elems; i++)
> > -                             ptr.p_s32[i] = ctrl->default_value;
> > +                             ptr.p_s32[i] = value;
> >               } else {
> >                       memset(ptr.p_s32 + from_idx, 0, elems * sizeof(s32));
> >               }
> > @@ -226,32 +266,63 @@ void v4l2_ctrl_type_op_init(const struct v4l2_ctrl *ctrl, u32 from_idx,
> >               memset(ptr.p_s32 + from_idx, 0, elems * sizeof(s32));
> >               break;
> >       case V4L2_CTRL_TYPE_U8:
> > -             memset(ptr.p_u8 + from_idx, ctrl->default_value, elems);
> > +             memset(ptr.p_u8 + from_idx, value, elems);
> >               break;
> >       case V4L2_CTRL_TYPE_U16:
> > -             if (ctrl->default_value) {
> > +             if (value) {
> >                       for (i = from_idx; i < tot_elems; i++)
> > -                             ptr.p_u16[i] = ctrl->default_value;
> > +                             ptr.p_u16[i] = value;
> >               } else {
> >                       memset(ptr.p_u16 + from_idx, 0, elems * sizeof(u16));
> >               }
> >               break;
> >       case V4L2_CTRL_TYPE_U32:
> > -             if (ctrl->default_value) {
> > +             if (value) {
> >                       for (i = from_idx; i < tot_elems; i++)
> > -                             ptr.p_u32[i] = ctrl->default_value;
> > +                             ptr.p_u32[i] = value;
> >               } else {
> >                       memset(ptr.p_u32 + from_idx, 0, elems * sizeof(u32));
> >               }
> >               break;
> >       default:
> > -             for (i = from_idx; i < tot_elems; i++)
> > -                     std_init_compound(ctrl, i, ptr);
> > +             for (i = from_idx; i < tot_elems; i++) {
> > +                     switch (which) {
> > +                     case V4L2_CTRL_WHICH_DEF_VAL:
> > +                             std_init_compound(ctrl, i, ptr);
> > +                             break;
> > +                     case V4L2_CTRL_WHICH_MAX_VAL:
> > +                             std_max_compound(ctrl, i, ptr);
> > +                             break;
> > +                     case V4L2_CTRL_WHICH_MIN_VAL:
> > +                             std_min_compound(ctrl, i, ptr);
> > +                             break;
> > +                     }
> > +             }
> >               break;
> >       }
> > +
> > +     return 0;
> > +}
> > +
> > +void v4l2_ctrl_type_op_init(const struct v4l2_ctrl *ctrl, u32 from_idx,
> > +                         union v4l2_ctrl_ptr ptr)
> > +{
> > +     __v4l2_ctrl_type_op_init(ctrl, from_idx, V4L2_CTRL_WHICH_DEF_VAL, ptr);
> >  }
> >  EXPORT_SYMBOL(v4l2_ctrl_type_op_init);
> >
> > +void v4l2_ctrl_type_op_minimum(const struct v4l2_ctrl *ctrl, u32 from_idx,
> > +                            union v4l2_ctrl_ptr ptr)
> > +{
> > +     __v4l2_ctrl_type_op_init(ctrl, from_idx, V4L2_CTRL_WHICH_MIN_VAL, ptr);
> > +}
> > +
> > +void v4l2_ctrl_type_op_maximum(const struct v4l2_ctrl *ctrl, u32 from_idx,
> > +                            union v4l2_ctrl_ptr ptr)
> > +{
> > +     __v4l2_ctrl_type_op_init(ctrl, from_idx, V4L2_CTRL_WHICH_MAX_VAL, ptr);
> > +}
> > +
> >  void v4l2_ctrl_type_op_log(const struct v4l2_ctrl *ctrl)
> >  {
> >       union v4l2_ctrl_ptr ptr = ctrl->p_cur;
> > @@ -1293,6 +1364,8 @@ EXPORT_SYMBOL(v4l2_ctrl_type_op_validate);
> >  static const struct v4l2_ctrl_type_ops std_type_ops = {
> >       .equal = v4l2_ctrl_type_op_equal,
> >       .init = v4l2_ctrl_type_op_init,
> > +     .minimum = v4l2_ctrl_type_op_minimum,
> > +     .maximum = v4l2_ctrl_type_op_maximum,
> >       .log = v4l2_ctrl_type_op_log,
> >       .validate = v4l2_ctrl_type_op_validate,
> >  };
> > @@ -1764,7 +1837,10 @@ static struct v4l2_ctrl *v4l2_ctrl_new(struct v4l2_ctrl_handler *hdl,
> >                       s64 min, s64 max, u64 step, s64 def,
> >                       const u32 dims[V4L2_CTRL_MAX_DIMS], u32 elem_size,
> >                       u32 flags, const char * const *qmenu,
> > -                     const s64 *qmenu_int, const union v4l2_ctrl_ptr p_def,
> > +                     const s64 *qmenu_int,
> > +                     const union v4l2_ctrl_ptr p_def,
> > +                     const union v4l2_ctrl_ptr p_min,
> > +                     const union v4l2_ctrl_ptr p_max,
> >                       void *priv)
> >  {
> >       struct v4l2_ctrl *ctrl;
> > @@ -1888,6 +1964,12 @@ static struct v4l2_ctrl *v4l2_ctrl_new(struct v4l2_ctrl_handler *hdl,
> >               break;
> >       }
> >
> > +     if (type < V4L2_CTRL_COMPOUND_TYPES &&
> > +         type != V4L2_CTRL_TYPE_BUTTON &&
> > +         type != V4L2_CTRL_TYPE_CTRL_CLASS &&
> > +         type != V4L2_CTRL_TYPE_STRING)
> > +             flags |= V4L2_CTRL_FLAG_HAS_WHICH_MIN_MAX;
> > +
> >       /* Sanity checks */
> >       if (id == 0 || name == NULL || !elem_size ||
> >           id >= V4L2_CID_PRIVATE_BASE ||
> > @@ -1896,6 +1978,21 @@ static struct v4l2_ctrl *v4l2_ctrl_new(struct v4l2_ctrl_handler *hdl,
> >               handler_set_err(hdl, -ERANGE);
> >               return NULL;
> >       }
> > +
> > +     if ((!p_def.p_const && p_min.p_const) ||
> > +         (p_min.p_const && !p_max.p_const) ||
> > +         (!p_min.p_const && p_max.p_const)) {
> > +             handler_set_err(hdl, -EINVAL);
> > +             return NULL;
> > +     }
>
> I would drop this. I think p_def, p_min and p_max can all be NULL (in which
> case the corresponding value is a memset(0)).
>
> > +
> > +     if (flags & V4L2_CTRL_FLAG_HAS_WHICH_MIN_MAX &&
> > +         type >= V4L2_CTRL_COMPOUND_TYPES &&
> > +         (!p_min.p_const || !p_max.p_const)) {
> > +             handler_set_err(hdl, -EINVAL);
> > +             return NULL;
> > +     }
>
> Same here. Suppose you have a compound control that for whatever reason has
> just a single fixed value, that happens to be all zeroes. Then you can set
> leave p_min/p_max to NULL, while still setting V4L2_CTRL_FLAG_HAS_WHICH_MIN_MAX.
>
> I'd just drop this test.
>
> > +
> >       err = check_range(type, min, max, step, def);
> >       if (err) {
> >               handler_set_err(hdl, err);
> > @@ -1937,6 +2034,8 @@ static struct v4l2_ctrl *v4l2_ctrl_new(struct v4l2_ctrl_handler *hdl,
> >
> >       if (type >= V4L2_CTRL_COMPOUND_TYPES && p_def.p_const)
> >               sz_extra += elem_size;
> > +     if (type >= V4L2_CTRL_COMPOUND_TYPES && p_min.p_const)
> > +             sz_extra += elem_size * 2;
>
> Since one of p_min or p_max can be NULL, just do this:
>
>         if (type >= V4L2_CTRL_COMPOUND_TYPES && p_min.p_const)
>                 sz_extra += elem_size;
>         if (type >= V4L2_CTRL_COMPOUND_TYPES && p_max.p_const)
>                 sz_extra += elem_size;
>
> >
> >       ctrl = kvzalloc(sizeof(*ctrl) + sz_extra, GFP_KERNEL);
> >       if (ctrl == NULL) {
> > @@ -2002,6 +2101,14 @@ static struct v4l2_ctrl *v4l2_ctrl_new(struct v4l2_ctrl_handler *hdl,
> >               memcpy(ctrl->p_def.p, p_def.p_const, elem_size);
> >       }
> >
> > +     if (flags & V4L2_CTRL_FLAG_HAS_WHICH_MIN_MAX &&
> > +         p_min.p_const && p_max.p_const) {
> > +             ctrl->p_min.p = ctrl->p_def.p + elem_size;
> > +             memcpy(ctrl->p_min.p, p_min.p_const, elem_size);
> > +             ctrl->p_max.p = ctrl->p_min.p + elem_size;
> > +             memcpy(ctrl->p_max.p, p_max.p_const, elem_size);
> > +     }
>
> This needs a similar modification.
>
> > +
> >       ctrl->type_ops->init(ctrl, 0, ctrl->p_cur);
> >       cur_to_new(ctrl);
> >
> > @@ -2052,7 +2159,8 @@ struct v4l2_ctrl *v4l2_ctrl_new_custom(struct v4l2_ctrl_handler *hdl,
> >                       type, min, max,
> >                       is_menu ? cfg->menu_skip_mask : step, def,
> >                       cfg->dims, cfg->elem_size,
> > -                     flags, qmenu, qmenu_int, cfg->p_def, priv);
> > +                     flags, qmenu, qmenu_int, cfg->p_def, cfg->p_min,
> > +                     cfg->p_max, priv);
> >       if (ctrl)
> >               ctrl->is_private = cfg->is_private;
> >       return ctrl;
> > @@ -2077,7 +2185,8 @@ struct v4l2_ctrl *v4l2_ctrl_new_std(struct v4l2_ctrl_handler *hdl,
> >       }
> >       return v4l2_ctrl_new(hdl, ops, NULL, id, name, type,
> >                            min, max, step, def, NULL, 0,
> > -                          flags, NULL, NULL, ptr_null, NULL);
> > +                          flags, NULL, NULL, ptr_null, ptr_null,
> > +                          ptr_null, NULL);
> >  }
> >  EXPORT_SYMBOL(v4l2_ctrl_new_std);
> >
> > @@ -2110,7 +2219,8 @@ struct v4l2_ctrl *v4l2_ctrl_new_std_menu(struct v4l2_ctrl_handler *hdl,
> >       }
> >       return v4l2_ctrl_new(hdl, ops, NULL, id, name, type,
> >                            0, max, mask, def, NULL, 0,
> > -                          flags, qmenu, qmenu_int, ptr_null, NULL);
> > +                          flags, qmenu, qmenu_int, ptr_null, ptr_null,
> > +                          ptr_null, NULL);
> >  }
> >  EXPORT_SYMBOL(v4l2_ctrl_new_std_menu);
> >
> > @@ -2142,7 +2252,8 @@ struct v4l2_ctrl *v4l2_ctrl_new_std_menu_items(struct v4l2_ctrl_handler *hdl,
> >       }
> >       return v4l2_ctrl_new(hdl, ops, NULL, id, name, type,
> >                            0, max, mask, def, NULL, 0,
> > -                          flags, qmenu, NULL, ptr_null, NULL);
> > +                          flags, qmenu, NULL, ptr_null, ptr_null,
> > +                          ptr_null, NULL);
> >
> >  }
> >  EXPORT_SYMBOL(v4l2_ctrl_new_std_menu_items);
> > @@ -2150,7 +2261,9 @@ EXPORT_SYMBOL(v4l2_ctrl_new_std_menu_items);
> >  /* Helper function for standard compound controls */
> >  struct v4l2_ctrl *v4l2_ctrl_new_std_compound(struct v4l2_ctrl_handler *hdl,
> >                               const struct v4l2_ctrl_ops *ops, u32 id,
> > -                             const union v4l2_ctrl_ptr p_def)
> > +                             const union v4l2_ctrl_ptr p_def,
> > +                             const union v4l2_ctrl_ptr p_min,
> > +                             const union v4l2_ctrl_ptr p_max)
> >  {
> >       const char *name;
> >       enum v4l2_ctrl_type type;
> > @@ -2164,7 +2277,7 @@ struct v4l2_ctrl *v4l2_ctrl_new_std_compound(struct v4l2_ctrl_handler *hdl,
> >       }
> >       return v4l2_ctrl_new(hdl, ops, NULL, id, name, type,
> >                            min, max, step, def, NULL, 0,
> > -                          flags, NULL, NULL, p_def, NULL);
> > +                          flags, NULL, NULL, p_def, p_min, p_max, NULL);
> >  }
> >  EXPORT_SYMBOL(v4l2_ctrl_new_std_compound);
> >
> > @@ -2188,7 +2301,8 @@ struct v4l2_ctrl *v4l2_ctrl_new_int_menu(struct v4l2_ctrl_handler *hdl,
> >       }
> >       return v4l2_ctrl_new(hdl, ops, NULL, id, name, type,
> >                            0, max, 0, def, NULL, 0,
> > -                          flags, NULL, qmenu_int, ptr_null, NULL);
> > +                          flags, NULL, qmenu_int, ptr_null, ptr_null,
> > +                          ptr_null, NULL);
> >  }
> >  EXPORT_SYMBOL(v4l2_ctrl_new_int_menu);
> >
> > diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
> > index 01ba27f2ef87..aaf68bfaa601 100644
> > --- a/drivers/media/v4l2-core/v4l2-ioctl.c
> > +++ b/drivers/media/v4l2-core/v4l2-ioctl.c
> > @@ -884,7 +884,9 @@ static bool check_ext_ctrls(struct v4l2_ext_controls *c, unsigned long ioctl)
> >                       return false;
> >               break;
> >       case V4L2_CTRL_WHICH_DEF_VAL:
> > -             /* Default value cannot be changed */
> > +     case V4L2_CTRL_WHICH_MIN_VAL:
> > +     case V4L2_CTRL_WHICH_MAX_VAL:
> > +             /* Default, minimum or maximum value cannot be changed */
> >               if (ioctl == VIDIOC_S_EXT_CTRLS ||
> >                   ioctl == VIDIOC_TRY_EXT_CTRLS) {
> >                       c->error_idx = c->count;
> > diff --git a/include/media/v4l2-ctrls.h b/include/media/v4l2-ctrls.h
> > index b0db167a3ac4..6e12493b30d3 100644
> > --- a/include/media/v4l2-ctrls.h
> > +++ b/include/media/v4l2-ctrls.h
> > @@ -133,6 +133,8 @@ struct v4l2_ctrl_ops {
> >   *
> >   * @equal: return true if all ctrl->elems array elements are equal.
> >   * @init: initialize the value for array elements from from_idx to ctrl->elems.
> > + * @minimum: set the value to the minimum value of the control.
> > + * @maximum: set the value to the maximum value of the control.
> >   * @log: log the value.
> >   * @validate: validate the value for ctrl->new_elems array elements.
> >   *   Return 0 on success and a negative value otherwise.
> > @@ -142,6 +144,10 @@ struct v4l2_ctrl_type_ops {
> >                     union v4l2_ctrl_ptr ptr1, union v4l2_ctrl_ptr ptr2);
> >       void (*init)(const struct v4l2_ctrl *ctrl, u32 from_idx,
> >                    union v4l2_ctrl_ptr ptr);
> > +     void (*minimum)(const struct v4l2_ctrl *ctrl, u32 idx,
> > +                     union v4l2_ctrl_ptr ptr);
> > +     void (*maximum)(const struct v4l2_ctrl *ctrl, u32 idx,
> > +                     union v4l2_ctrl_ptr ptr);
> >       void (*log)(const struct v4l2_ctrl *ctrl);
> >       int (*validate)(const struct v4l2_ctrl *ctrl, union v4l2_ctrl_ptr ptr);
> >  };
> > @@ -247,6 +253,12 @@ typedef void (*v4l2_ctrl_notify_fnc)(struct v4l2_ctrl *ctrl, void *priv);
> >   * @p_def:   The control's default value represented via a union which
> >   *           provides a standard way of accessing control types
> >   *           through a pointer (for compound controls only).
> > + * @p_min:   The control's minimum value represented via a union which
> > + *           provides a standard way of accessing control types
> > + *           through a pointer (for compound controls only).
> > + * @p_max:   The control's maximum value represented via a union which
> > + *           provides a standard way of accessing control types
> > + *           through a pointer (for compound controls only).
> >   * @p_cur:   The control's current value represented via a union which
> >   *           provides a standard way of accessing control types
> >   *           through a pointer.
> > @@ -306,6 +318,8 @@ struct v4l2_ctrl {
> >       } cur;
> >
> >       union v4l2_ctrl_ptr p_def;
> > +     union v4l2_ctrl_ptr p_min;
> > +     union v4l2_ctrl_ptr p_max;
> >       union v4l2_ctrl_ptr p_new;
> >       union v4l2_ctrl_ptr p_cur;
> >  };
> > @@ -425,6 +439,8 @@ struct v4l2_ctrl_handler {
> >   * @step:    The control's step value for non-menu controls.
> >   * @def:     The control's default value.
> >   * @p_def:   The control's default value for compound controls.
> > + * @p_min:   The control's minimum value for compound controls.
> > + * @p_max:   The control's maximum value for compound controls.
> >   * @dims:    The size of each dimension.
> >   * @elem_size:       The size in bytes of the control.
> >   * @flags:   The control's flags.
> > @@ -454,6 +470,8 @@ struct v4l2_ctrl_config {
> >       u64 step;
> >       s64 def;
> >       union v4l2_ctrl_ptr p_def;
> > +     union v4l2_ctrl_ptr p_min;
> > +     union v4l2_ctrl_ptr p_max;
> >       u32 dims[V4L2_CTRL_MAX_DIMS];
> >       u32 elem_size;
> >       u32 flags;
> > @@ -723,17 +741,23 @@ struct v4l2_ctrl *v4l2_ctrl_new_std_menu_items(struct v4l2_ctrl_handler *hdl,
> >   * @ops:       The control ops.
> >   * @id:        The control ID.
> >   * @p_def:     The control's default value.
> > + * @p_min:     The control's minimum value.
> > + * @p_max:     The control's maximum value.
> >   *
> > - * Sames as v4l2_ctrl_new_std(), but with support to compound controls, thanks
> > - * to the @p_def field. Use v4l2_ctrl_ptr_create() to create @p_def from a
> > - * pointer. Use v4l2_ctrl_ptr_create(NULL) if the default value of the
> > - * compound control should be all zeroes.
> > + * Same as v4l2_ctrl_new_std(), but with support to compound controls, thanks
> > + * to the @p_def/min/max fields. Use v4l2_ctrl_ptr_create() to create
> > + * @p_def/min/max from a pointer. Use v4l2_ctrl_ptr_create(NULL) if the
> > + * default value of the compound control should be all zeroes. Use
> > + * v4l2_ctrl_ptr_create(NULL) if the min/max value of the compound control
> > + * is not defined, -ENODATA will be returned in this case.
>
> This is outdated and should be:
>
>  * @p_def/min/max from a pointer. Use v4l2_ctrl_ptr_create(NULL) if the
>  * default, minimum or maximum value of the compound control should be all zeroes.
>
> >   *
> >   */
> >  struct v4l2_ctrl *v4l2_ctrl_new_std_compound(struct v4l2_ctrl_handler *hdl,
> >                                            const struct v4l2_ctrl_ops *ops,
> >                                            u32 id,
> > -                                          const union v4l2_ctrl_ptr p_def);
> > +                                          const union v4l2_ctrl_ptr p_def,
> > +                                          const union v4l2_ctrl_ptr p_min,
> > +                                          const union v4l2_ctrl_ptr p_max);
> >
> >  /**
> >   * v4l2_ctrl_new_int_menu() - Create a new standard V4L2 integer menu control.
> > diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
> > index 089d553cf736..d7670aaf3b5f 100644
> > --- a/include/uapi/linux/videodev2.h
> > +++ b/include/uapi/linux/videodev2.h
> > @@ -1863,6 +1863,8 @@ struct v4l2_ext_controls {
> >  #define V4L2_CTRL_WHICH_CUR_VAL   0
> >  #define V4L2_CTRL_WHICH_DEF_VAL   0x0f000000
> >  #define V4L2_CTRL_WHICH_REQUEST_VAL 0x0f010000
> > +#define V4L2_CTRL_WHICH_MIN_VAL   0x0f020000
> > +#define V4L2_CTRL_WHICH_MAX_VAL   0x0f030000
> >
> >  enum v4l2_ctrl_type {
> >       V4L2_CTRL_TYPE_INTEGER       = 1,
> > @@ -1970,6 +1972,7 @@ struct v4l2_querymenu {
> >  #define V4L2_CTRL_FLAG_EXECUTE_ON_WRITE      0x0200
> >  #define V4L2_CTRL_FLAG_MODIFY_LAYOUT 0x0400
> >  #define V4L2_CTRL_FLAG_DYNAMIC_ARRAY 0x0800
> > +#define V4L2_CTRL_FLAG_HAS_WHICH_MIN_MAX 0x1000
> >
> >  /*  Query flags, to be ORed with the control ID */
> >  #define V4L2_CTRL_FLAG_NEXT_CTRL     0x80000000
>
> Regards,
>
>         Hans
diff mbox series

Patch

diff --git a/Documentation/userspace-api/media/v4l/vidioc-g-ext-ctrls.rst b/Documentation/userspace-api/media/v4l/vidioc-g-ext-ctrls.rst
index 7b1001d11f9c..b4bf016411d3 100644
--- a/Documentation/userspace-api/media/v4l/vidioc-g-ext-ctrls.rst
+++ b/Documentation/userspace-api/media/v4l/vidioc-g-ext-ctrls.rst
@@ -330,14 +330,26 @@  still cause this situation.
       - Which value of the control to get/set/try.
     * - :cspan:`2` ``V4L2_CTRL_WHICH_CUR_VAL`` will return the current value of
 	the control, ``V4L2_CTRL_WHICH_DEF_VAL`` will return the default
+	value of the control, ``V4L2_CTRL_WHICH_MIN_VAL`` will return the minimum
+	value of the control, ``V4L2_CTRL_WHICH_MAX_VAL`` will return the maximum
 	value of the control and ``V4L2_CTRL_WHICH_REQUEST_VAL`` indicates that
 	these controls have to be retrieved from a request or tried/set for
 	a request. In the latter case the ``request_fd`` field contains the
 	file descriptor of the request that should be used. If the device
 	does not support requests, then ``EACCES`` will be returned.
 
-	When using ``V4L2_CTRL_WHICH_DEF_VAL`` be aware that you can only
-	get the default value of the control, you cannot set or try it.
+	When using ``V4L2_CTRL_WHICH_DEF_VAL``, ``V4L2_CTRL_WHICH_MIN_VAL``
+	or ``V4L2_CTRL_WHICH_MAX_VAL`` be aware that you can only get the
+	default/minimum/maximum value of the control, you cannot set or try it.
+
+	Whether a control supports querying the minimum and maximum values using
+	``V4L2_CTRL_WHICH_MIN_VAL`` and ``V4L2_CTRL_WHICH_MAX_VAL`` is indicated
+	by the ``V4L2_CTRL_FLAG_HAS_WHICH_MIN_MAX`` flag. Most non-compound
+	control types support this. For controls with compound types, the
+	definition of minimum/maximum values are provided by
+	the control documentation. If a compound control does not document the
+	meaning of minimum/maximum value, then querying the minimum or maximum
+	value will result in the error code -EINVAL.
 
 	For backwards compatibility you can also use a control class here
 	(see :ref:`ctrl-class`). In that case all controls have to
diff --git a/Documentation/userspace-api/media/v4l/vidioc-queryctrl.rst b/Documentation/userspace-api/media/v4l/vidioc-queryctrl.rst
index 56d5c8b0b88b..b39f7e27bbbe 100644
--- a/Documentation/userspace-api/media/v4l/vidioc-queryctrl.rst
+++ b/Documentation/userspace-api/media/v4l/vidioc-queryctrl.rst
@@ -447,7 +447,10 @@  See also the examples in :ref:`control`.
       - n/a
       - A struct :c:type:`v4l2_rect`, containing a rectangle described by
 	the position of its top-left corner, the width and the height. Units
-	depend on the use case.
+	depend on the use case. Support for ``V4L2_CTRL_WHICH_MIN_VAL`` and
+	``V4L2_CTRL_WHICH_MAX_VAL`` is optional and depends on the
+	``V4L2_CTRL_FLAG_HAS_WHICH_MIN_MAX`` flag. See the documentation of
+	the specific control on how to interpret the minimum and maximum values.
     * - ``V4L2_CTRL_TYPE_H264_SPS``
       - n/a
       - n/a
@@ -664,6 +667,10 @@  See also the examples in :ref:`control`.
 	``dims[0]``. So setting the control with a differently sized
 	array will change the ``elems`` field when the control is
 	queried afterwards.
+    * - ``V4L2_CTRL_FLAG_HAS_WHICH_MIN_MAX``
+      - 0x1000
+      - This control supports getting minimum and maximum values using
+      vidioc_g_ext_ctrls with V4L2_CTRL_WHICH_MIN/MAX_VAL.
 
 Return Value
 ============
diff --git a/Documentation/userspace-api/media/videodev2.h.rst.exceptions b/Documentation/userspace-api/media/videodev2.h.rst.exceptions
index c46082ef0e4d..a417af25e9a4 100644
--- a/Documentation/userspace-api/media/videodev2.h.rst.exceptions
+++ b/Documentation/userspace-api/media/videodev2.h.rst.exceptions
@@ -393,6 +393,7 @@  replace define V4L2_CTRL_FLAG_HAS_PAYLOAD control-flags
 replace define V4L2_CTRL_FLAG_EXECUTE_ON_WRITE control-flags
 replace define V4L2_CTRL_FLAG_MODIFY_LAYOUT control-flags
 replace define V4L2_CTRL_FLAG_DYNAMIC_ARRAY control-flags
+replace define V4L2_CTRL_FLAG_HAS_WHICH_MIN_MAX control-flags
 
 replace define V4L2_CTRL_FLAG_NEXT_CTRL control
 replace define V4L2_CTRL_FLAG_NEXT_COMPOUND control
@@ -567,6 +568,8 @@  ignore define V4L2_CTRL_DRIVER_PRIV
 ignore define V4L2_CTRL_MAX_DIMS
 ignore define V4L2_CTRL_WHICH_CUR_VAL
 ignore define V4L2_CTRL_WHICH_DEF_VAL
+ignore define V4L2_CTRL_WHICH_MIN_VAL
+ignore define V4L2_CTRL_WHICH_MAX_VAL
 ignore define V4L2_CTRL_WHICH_REQUEST_VAL
 ignore define V4L2_OUT_CAP_CUSTOM_TIMINGS
 ignore define V4L2_CID_MAX_CTRLS
diff --git a/drivers/media/i2c/imx214.c b/drivers/media/i2c/imx214.c
index 2f9c8582f940..8db4a5eb1737 100644
--- a/drivers/media/i2c/imx214.c
+++ b/drivers/media/i2c/imx214.c
@@ -1037,7 +1037,10 @@  static int imx214_probe(struct i2c_client *client)
 	imx214->unit_size = v4l2_ctrl_new_std_compound(&imx214->ctrls,
 				NULL,
 				V4L2_CID_UNIT_CELL_SIZE,
-				v4l2_ctrl_ptr_create((void *)&unit_size));
+				v4l2_ctrl_ptr_create((void *)&unit_size),
+				v4l2_ctrl_ptr_create(NULL),
+				v4l2_ctrl_ptr_create(NULL));
+
 	ret = imx214->ctrls.error;
 	if (ret) {
 		dev_err(&client->dev, "%s control init failed (%d)\n",
diff --git a/drivers/media/platform/qcom/venus/venc_ctrls.c b/drivers/media/platform/qcom/venus/venc_ctrls.c
index 7468e43800a9..28eca8f9d148 100644
--- a/drivers/media/platform/qcom/venus/venc_ctrls.c
+++ b/drivers/media/platform/qcom/venus/venc_ctrls.c
@@ -607,11 +607,16 @@  int venc_ctrl_init(struct venus_inst *inst)
 
 	v4l2_ctrl_new_std_compound(&inst->ctrl_handler, &venc_ctrl_ops,
 				   V4L2_CID_COLORIMETRY_HDR10_CLL_INFO,
-				   v4l2_ctrl_ptr_create(&p_hdr10_cll));
+				   v4l2_ctrl_ptr_create(&p_hdr10_cll),
+				   v4l2_ctrl_ptr_create(NULL),
+				   v4l2_ctrl_ptr_create(NULL));
 
 	v4l2_ctrl_new_std_compound(&inst->ctrl_handler, &venc_ctrl_ops,
 				   V4L2_CID_COLORIMETRY_HDR10_MASTERING_DISPLAY,
-				   v4l2_ctrl_ptr_create((void *)&p_hdr10_mastering));
+				   v4l2_ctrl_ptr_create((void *)&p_hdr10_mastering),
+				   v4l2_ctrl_ptr_create(NULL),
+				   v4l2_ctrl_ptr_create(NULL));
+
 
 	v4l2_ctrl_new_std_menu(&inst->ctrl_handler, &venc_ctrl_ops,
 			       V4L2_CID_MPEG_VIDEO_INTRA_REFRESH_PERIOD_TYPE,
diff --git a/drivers/media/v4l2-core/v4l2-ctrls-api.c b/drivers/media/v4l2-core/v4l2-ctrls-api.c
index 002ea6588edf..d022e1ed4835 100644
--- a/drivers/media/v4l2-core/v4l2-ctrls-api.c
+++ b/drivers/media/v4l2-core/v4l2-ctrls-api.c
@@ -94,6 +94,22 @@  static int def_to_user(struct v4l2_ext_control *c, struct v4l2_ctrl *ctrl)
 	return ptr_to_user(c, ctrl, ctrl->p_new);
 }
 
+/* Helper function: copy the minimum control value back to the caller */
+static int min_to_user(struct v4l2_ext_control *c, struct v4l2_ctrl *ctrl)
+{
+	ctrl->type_ops->minimum(ctrl, 0, ctrl->p_new);
+
+	return ptr_to_user(c, ctrl, ctrl->p_new);
+}
+
+/* Helper function: copy the maximum control value back to the caller */
+static int max_to_user(struct v4l2_ext_control *c, struct v4l2_ctrl *ctrl)
+{
+	ctrl->type_ops->maximum(ctrl, 0, ctrl->p_new);
+
+	return ptr_to_user(c, ctrl, ctrl->p_new);
+}
+
 /* Helper function: copy the caller-provider value as the new control value */
 static int user_to_new(struct v4l2_ext_control *c, struct v4l2_ctrl *ctrl)
 {
@@ -229,8 +245,8 @@  static int prepare_ext_ctrls(struct v4l2_ctrl_handler *hdl,
 		cs->error_idx = i;
 
 		if (cs->which &&
-		    cs->which != V4L2_CTRL_WHICH_DEF_VAL &&
-		    cs->which != V4L2_CTRL_WHICH_REQUEST_VAL &&
+		    (cs->which < V4L2_CTRL_WHICH_DEF_VAL ||
+		     cs->which > V4L2_CTRL_WHICH_MAX_VAL) &&
 		    V4L2_CTRL_ID2WHICH(id) != cs->which) {
 			dprintk(vdev,
 				"invalid which 0x%x or control id 0x%x\n",
@@ -259,6 +275,15 @@  static int prepare_ext_ctrls(struct v4l2_ctrl_handler *hdl,
 			return -EINVAL;
 		}
 
+		if (!(ctrl->flags & V4L2_CTRL_FLAG_HAS_WHICH_MIN_MAX) &&
+		    (cs->which == V4L2_CTRL_WHICH_MIN_VAL ||
+		     cs->which == V4L2_CTRL_WHICH_MAX_VAL)) {
+			dprintk(vdev,
+				"invalid which 0x%x or control id 0x%x\n",
+				cs->which, id);
+			return -EINVAL;
+		}
+
 		if (ctrl->cluster[0]->ncontrols > 1)
 			have_clusters = true;
 		if (ctrl->cluster[0] != ctrl)
@@ -368,8 +393,8 @@  static int prepare_ext_ctrls(struct v4l2_ctrl_handler *hdl,
  */
 static int class_check(struct v4l2_ctrl_handler *hdl, u32 which)
 {
-	if (which == 0 || which == V4L2_CTRL_WHICH_DEF_VAL ||
-	    which == V4L2_CTRL_WHICH_REQUEST_VAL)
+	if (which == 0 || (which >= V4L2_CTRL_WHICH_DEF_VAL &&
+			   which <= V4L2_CTRL_WHICH_MAX_VAL))
 		return 0;
 	return find_ref_lock(hdl, which | 1) ? 0 : -EINVAL;
 }
@@ -389,10 +414,12 @@  int v4l2_g_ext_ctrls_common(struct v4l2_ctrl_handler *hdl,
 	struct v4l2_ctrl_helper *helpers = helper;
 	int ret;
 	int i, j;
-	bool is_default, is_request;
+	bool is_default, is_request, is_min, is_max;
 
 	is_default = (cs->which == V4L2_CTRL_WHICH_DEF_VAL);
 	is_request = (cs->which == V4L2_CTRL_WHICH_REQUEST_VAL);
+	is_min = (cs->which == V4L2_CTRL_WHICH_MIN_VAL);
+	is_max = (cs->which == V4L2_CTRL_WHICH_MAX_VAL);
 
 	cs->error_idx = cs->count;
 	cs->which = V4L2_CTRL_ID2WHICH(cs->which);
@@ -432,13 +459,14 @@  int v4l2_g_ext_ctrls_common(struct v4l2_ctrl_handler *hdl,
 
 		/*
 		 * g_volatile_ctrl will update the new control values.
-		 * This makes no sense for V4L2_CTRL_WHICH_DEF_VAL and
+		 * This makes no sense for V4L2_CTRL_WHICH_DEF_VAL,
+		 * V4L2_CTRL_WHICH_MIN_VAL, V4L2_CTRL_WHICH_MAX_VAL and
 		 * V4L2_CTRL_WHICH_REQUEST_VAL. In the case of requests
 		 * it is v4l2_ctrl_request_complete() that copies the
 		 * volatile controls at the time of request completion
 		 * to the request, so you don't want to do that again.
 		 */
-		if (!is_default && !is_request &&
+		if (!is_default && !is_request && !is_min && !is_max &&
 		    ((master->flags & V4L2_CTRL_FLAG_VOLATILE) ||
 		    (master->has_volatiles && !is_cur_manual(master)))) {
 			for (j = 0; j < master->ncontrols; j++)
@@ -467,6 +495,10 @@  int v4l2_g_ext_ctrls_common(struct v4l2_ctrl_handler *hdl,
 				ret = -ENOMEM;
 			else if (is_request && ref->p_req_valid)
 				ret = req_to_user(cs->controls + idx, ref);
+			else if (is_min)
+				ret = min_to_user(cs->controls + idx, ref->ctrl);
+			else if (is_max)
+				ret = max_to_user(cs->controls + idx, ref->ctrl);
 			else if (is_volatile)
 				ret = new_to_user(cs->controls + idx, ref->ctrl);
 			else
@@ -564,9 +596,11 @@  int try_set_ext_ctrls_common(struct v4l2_fh *fh,
 
 	cs->error_idx = cs->count;
 
-	/* Default value cannot be changed */
-	if (cs->which == V4L2_CTRL_WHICH_DEF_VAL) {
-		dprintk(vdev, "%s: cannot change default value\n",
+	/* Default/minimum/maximum values cannot be changed */
+	if (cs->which == V4L2_CTRL_WHICH_DEF_VAL ||
+	    cs->which == V4L2_CTRL_WHICH_MIN_VAL ||
+	    cs->which == V4L2_CTRL_WHICH_MAX_VAL) {
+		dprintk(vdev, "%s: cannot change default/min/max value\n",
 			video_device_node_name(vdev));
 		return -EINVAL;
 	}
diff --git a/drivers/media/v4l2-core/v4l2-ctrls-core.c b/drivers/media/v4l2-core/v4l2-ctrls-core.c
index f1486ab032cf..f36d54810dbc 100644
--- a/drivers/media/v4l2-core/v4l2-ctrls-core.c
+++ b/drivers/media/v4l2-core/v4l2-ctrls-core.c
@@ -182,29 +182,69 @@  static void std_init_compound(const struct v4l2_ctrl *ctrl, u32 idx,
 	}
 }
 
-void v4l2_ctrl_type_op_init(const struct v4l2_ctrl *ctrl, u32 from_idx,
+static void std_min_compound(const struct v4l2_ctrl *ctrl, u32 idx,
+			    union v4l2_ctrl_ptr ptr)
+{
+	void *p = ptr.p + idx * ctrl->elem_size;
+
+	if (ctrl->p_min.p_const)
+		memcpy(p, ctrl->p_min.p_const, ctrl->elem_size);
+	else
+		memset(p, 0, ctrl->elem_size);
+}
+
+static void std_max_compound(const struct v4l2_ctrl *ctrl, u32 idx,
 			    union v4l2_ctrl_ptr ptr)
+{
+	void *p = ptr.p + idx * ctrl->elem_size;
+
+	if (ctrl->p_min.p_const)
+		memcpy(p, ctrl->p_max.p_const, ctrl->elem_size);
+	else
+		memset(p, 0, ctrl->elem_size);
+}
+
+static int __v4l2_ctrl_type_op_init(const struct v4l2_ctrl *ctrl, u32 from_idx,
+				    u32 which, union v4l2_ctrl_ptr ptr)
 {
 	unsigned int i;
 	u32 tot_elems = ctrl->elems;
 	u32 elems = tot_elems - from_idx;
+	s64 value;
 
 	if (from_idx >= tot_elems)
-		return;
+		return -EINVAL;
+
+	switch (which) {
+	case V4L2_CTRL_WHICH_DEF_VAL:
+		value = ctrl->default_value;
+		break;
+	case V4L2_CTRL_WHICH_MAX_VAL:
+		value = ctrl->maximum;
+		break;
+	case V4L2_CTRL_WHICH_MIN_VAL:
+		value = ctrl->minimum;
+		break;
+	default:
+		return -EINVAL;
+	}
 
 	switch (ctrl->type) {
 	case V4L2_CTRL_TYPE_STRING:
+		if (which == V4L2_CTRL_WHICH_DEF_VAL)
+			value = ctrl->minimum;
+
 		for (i = from_idx; i < tot_elems; i++) {
 			unsigned int offset = i * ctrl->elem_size;
 
-			memset(ptr.p_char + offset, ' ', ctrl->minimum);
-			ptr.p_char[offset + ctrl->minimum] = '\0';
+			memset(ptr.p_char + offset, ' ', value);
+			ptr.p_char[offset + value] = '\0';
 		}
 		break;
 	case V4L2_CTRL_TYPE_INTEGER64:
-		if (ctrl->default_value) {
+		if (value) {
 			for (i = from_idx; i < tot_elems; i++)
-				ptr.p_s64[i] = ctrl->default_value;
+				ptr.p_s64[i] = value;
 		} else {
 			memset(ptr.p_s64 + from_idx, 0, elems * sizeof(s64));
 		}
@@ -214,9 +254,9 @@  void v4l2_ctrl_type_op_init(const struct v4l2_ctrl *ctrl, u32 from_idx,
 	case V4L2_CTRL_TYPE_MENU:
 	case V4L2_CTRL_TYPE_BITMASK:
 	case V4L2_CTRL_TYPE_BOOLEAN:
-		if (ctrl->default_value) {
+		if (value) {
 			for (i = from_idx; i < tot_elems; i++)
-				ptr.p_s32[i] = ctrl->default_value;
+				ptr.p_s32[i] = value;
 		} else {
 			memset(ptr.p_s32 + from_idx, 0, elems * sizeof(s32));
 		}
@@ -226,32 +266,63 @@  void v4l2_ctrl_type_op_init(const struct v4l2_ctrl *ctrl, u32 from_idx,
 		memset(ptr.p_s32 + from_idx, 0, elems * sizeof(s32));
 		break;
 	case V4L2_CTRL_TYPE_U8:
-		memset(ptr.p_u8 + from_idx, ctrl->default_value, elems);
+		memset(ptr.p_u8 + from_idx, value, elems);
 		break;
 	case V4L2_CTRL_TYPE_U16:
-		if (ctrl->default_value) {
+		if (value) {
 			for (i = from_idx; i < tot_elems; i++)
-				ptr.p_u16[i] = ctrl->default_value;
+				ptr.p_u16[i] = value;
 		} else {
 			memset(ptr.p_u16 + from_idx, 0, elems * sizeof(u16));
 		}
 		break;
 	case V4L2_CTRL_TYPE_U32:
-		if (ctrl->default_value) {
+		if (value) {
 			for (i = from_idx; i < tot_elems; i++)
-				ptr.p_u32[i] = ctrl->default_value;
+				ptr.p_u32[i] = value;
 		} else {
 			memset(ptr.p_u32 + from_idx, 0, elems * sizeof(u32));
 		}
 		break;
 	default:
-		for (i = from_idx; i < tot_elems; i++)
-			std_init_compound(ctrl, i, ptr);
+		for (i = from_idx; i < tot_elems; i++) {
+			switch (which) {
+			case V4L2_CTRL_WHICH_DEF_VAL:
+				std_init_compound(ctrl, i, ptr);
+				break;
+			case V4L2_CTRL_WHICH_MAX_VAL:
+				std_max_compound(ctrl, i, ptr);
+				break;
+			case V4L2_CTRL_WHICH_MIN_VAL:
+				std_min_compound(ctrl, i, ptr);
+				break;
+			}
+		}
 		break;
 	}
+
+	return 0;
+}
+
+void v4l2_ctrl_type_op_init(const struct v4l2_ctrl *ctrl, u32 from_idx,
+			    union v4l2_ctrl_ptr ptr)
+{
+	__v4l2_ctrl_type_op_init(ctrl, from_idx, V4L2_CTRL_WHICH_DEF_VAL, ptr);
 }
 EXPORT_SYMBOL(v4l2_ctrl_type_op_init);
 
+void v4l2_ctrl_type_op_minimum(const struct v4l2_ctrl *ctrl, u32 from_idx,
+			       union v4l2_ctrl_ptr ptr)
+{
+	__v4l2_ctrl_type_op_init(ctrl, from_idx, V4L2_CTRL_WHICH_MIN_VAL, ptr);
+}
+
+void v4l2_ctrl_type_op_maximum(const struct v4l2_ctrl *ctrl, u32 from_idx,
+			       union v4l2_ctrl_ptr ptr)
+{
+	__v4l2_ctrl_type_op_init(ctrl, from_idx, V4L2_CTRL_WHICH_MAX_VAL, ptr);
+}
+
 void v4l2_ctrl_type_op_log(const struct v4l2_ctrl *ctrl)
 {
 	union v4l2_ctrl_ptr ptr = ctrl->p_cur;
@@ -1293,6 +1364,8 @@  EXPORT_SYMBOL(v4l2_ctrl_type_op_validate);
 static const struct v4l2_ctrl_type_ops std_type_ops = {
 	.equal = v4l2_ctrl_type_op_equal,
 	.init = v4l2_ctrl_type_op_init,
+	.minimum = v4l2_ctrl_type_op_minimum,
+	.maximum = v4l2_ctrl_type_op_maximum,
 	.log = v4l2_ctrl_type_op_log,
 	.validate = v4l2_ctrl_type_op_validate,
 };
@@ -1764,7 +1837,10 @@  static struct v4l2_ctrl *v4l2_ctrl_new(struct v4l2_ctrl_handler *hdl,
 			s64 min, s64 max, u64 step, s64 def,
 			const u32 dims[V4L2_CTRL_MAX_DIMS], u32 elem_size,
 			u32 flags, const char * const *qmenu,
-			const s64 *qmenu_int, const union v4l2_ctrl_ptr p_def,
+			const s64 *qmenu_int,
+			const union v4l2_ctrl_ptr p_def,
+			const union v4l2_ctrl_ptr p_min,
+			const union v4l2_ctrl_ptr p_max,
 			void *priv)
 {
 	struct v4l2_ctrl *ctrl;
@@ -1888,6 +1964,12 @@  static struct v4l2_ctrl *v4l2_ctrl_new(struct v4l2_ctrl_handler *hdl,
 		break;
 	}
 
+	if (type < V4L2_CTRL_COMPOUND_TYPES &&
+	    type != V4L2_CTRL_TYPE_BUTTON &&
+	    type != V4L2_CTRL_TYPE_CTRL_CLASS &&
+	    type != V4L2_CTRL_TYPE_STRING)
+		flags |= V4L2_CTRL_FLAG_HAS_WHICH_MIN_MAX;
+
 	/* Sanity checks */
 	if (id == 0 || name == NULL || !elem_size ||
 	    id >= V4L2_CID_PRIVATE_BASE ||
@@ -1896,6 +1978,21 @@  static struct v4l2_ctrl *v4l2_ctrl_new(struct v4l2_ctrl_handler *hdl,
 		handler_set_err(hdl, -ERANGE);
 		return NULL;
 	}
+
+	if ((!p_def.p_const && p_min.p_const) ||
+	    (p_min.p_const && !p_max.p_const) ||
+	    (!p_min.p_const && p_max.p_const)) {
+		handler_set_err(hdl, -EINVAL);
+		return NULL;
+	}
+
+	if (flags & V4L2_CTRL_FLAG_HAS_WHICH_MIN_MAX &&
+	    type >= V4L2_CTRL_COMPOUND_TYPES &&
+	    (!p_min.p_const || !p_max.p_const)) {
+		handler_set_err(hdl, -EINVAL);
+		return NULL;
+	}
+
 	err = check_range(type, min, max, step, def);
 	if (err) {
 		handler_set_err(hdl, err);
@@ -1937,6 +2034,8 @@  static struct v4l2_ctrl *v4l2_ctrl_new(struct v4l2_ctrl_handler *hdl,
 
 	if (type >= V4L2_CTRL_COMPOUND_TYPES && p_def.p_const)
 		sz_extra += elem_size;
+	if (type >= V4L2_CTRL_COMPOUND_TYPES && p_min.p_const)
+		sz_extra += elem_size * 2;
 
 	ctrl = kvzalloc(sizeof(*ctrl) + sz_extra, GFP_KERNEL);
 	if (ctrl == NULL) {
@@ -2002,6 +2101,14 @@  static struct v4l2_ctrl *v4l2_ctrl_new(struct v4l2_ctrl_handler *hdl,
 		memcpy(ctrl->p_def.p, p_def.p_const, elem_size);
 	}
 
+	if (flags & V4L2_CTRL_FLAG_HAS_WHICH_MIN_MAX &&
+	    p_min.p_const && p_max.p_const) {
+		ctrl->p_min.p = ctrl->p_def.p + elem_size;
+		memcpy(ctrl->p_min.p, p_min.p_const, elem_size);
+		ctrl->p_max.p = ctrl->p_min.p + elem_size;
+		memcpy(ctrl->p_max.p, p_max.p_const, elem_size);
+	}
+
 	ctrl->type_ops->init(ctrl, 0, ctrl->p_cur);
 	cur_to_new(ctrl);
 
@@ -2052,7 +2159,8 @@  struct v4l2_ctrl *v4l2_ctrl_new_custom(struct v4l2_ctrl_handler *hdl,
 			type, min, max,
 			is_menu ? cfg->menu_skip_mask : step, def,
 			cfg->dims, cfg->elem_size,
-			flags, qmenu, qmenu_int, cfg->p_def, priv);
+			flags, qmenu, qmenu_int, cfg->p_def, cfg->p_min,
+			cfg->p_max, priv);
 	if (ctrl)
 		ctrl->is_private = cfg->is_private;
 	return ctrl;
@@ -2077,7 +2185,8 @@  struct v4l2_ctrl *v4l2_ctrl_new_std(struct v4l2_ctrl_handler *hdl,
 	}
 	return v4l2_ctrl_new(hdl, ops, NULL, id, name, type,
 			     min, max, step, def, NULL, 0,
-			     flags, NULL, NULL, ptr_null, NULL);
+			     flags, NULL, NULL, ptr_null, ptr_null,
+			     ptr_null, NULL);
 }
 EXPORT_SYMBOL(v4l2_ctrl_new_std);
 
@@ -2110,7 +2219,8 @@  struct v4l2_ctrl *v4l2_ctrl_new_std_menu(struct v4l2_ctrl_handler *hdl,
 	}
 	return v4l2_ctrl_new(hdl, ops, NULL, id, name, type,
 			     0, max, mask, def, NULL, 0,
-			     flags, qmenu, qmenu_int, ptr_null, NULL);
+			     flags, qmenu, qmenu_int, ptr_null, ptr_null,
+			     ptr_null, NULL);
 }
 EXPORT_SYMBOL(v4l2_ctrl_new_std_menu);
 
@@ -2142,7 +2252,8 @@  struct v4l2_ctrl *v4l2_ctrl_new_std_menu_items(struct v4l2_ctrl_handler *hdl,
 	}
 	return v4l2_ctrl_new(hdl, ops, NULL, id, name, type,
 			     0, max, mask, def, NULL, 0,
-			     flags, qmenu, NULL, ptr_null, NULL);
+			     flags, qmenu, NULL, ptr_null, ptr_null,
+			     ptr_null, NULL);
 
 }
 EXPORT_SYMBOL(v4l2_ctrl_new_std_menu_items);
@@ -2150,7 +2261,9 @@  EXPORT_SYMBOL(v4l2_ctrl_new_std_menu_items);
 /* Helper function for standard compound controls */
 struct v4l2_ctrl *v4l2_ctrl_new_std_compound(struct v4l2_ctrl_handler *hdl,
 				const struct v4l2_ctrl_ops *ops, u32 id,
-				const union v4l2_ctrl_ptr p_def)
+				const union v4l2_ctrl_ptr p_def,
+				const union v4l2_ctrl_ptr p_min,
+				const union v4l2_ctrl_ptr p_max)
 {
 	const char *name;
 	enum v4l2_ctrl_type type;
@@ -2164,7 +2277,7 @@  struct v4l2_ctrl *v4l2_ctrl_new_std_compound(struct v4l2_ctrl_handler *hdl,
 	}
 	return v4l2_ctrl_new(hdl, ops, NULL, id, name, type,
 			     min, max, step, def, NULL, 0,
-			     flags, NULL, NULL, p_def, NULL);
+			     flags, NULL, NULL, p_def, p_min, p_max, NULL);
 }
 EXPORT_SYMBOL(v4l2_ctrl_new_std_compound);
 
@@ -2188,7 +2301,8 @@  struct v4l2_ctrl *v4l2_ctrl_new_int_menu(struct v4l2_ctrl_handler *hdl,
 	}
 	return v4l2_ctrl_new(hdl, ops, NULL, id, name, type,
 			     0, max, 0, def, NULL, 0,
-			     flags, NULL, qmenu_int, ptr_null, NULL);
+			     flags, NULL, qmenu_int, ptr_null, ptr_null,
+			     ptr_null, NULL);
 }
 EXPORT_SYMBOL(v4l2_ctrl_new_int_menu);
 
diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
index 01ba27f2ef87..aaf68bfaa601 100644
--- a/drivers/media/v4l2-core/v4l2-ioctl.c
+++ b/drivers/media/v4l2-core/v4l2-ioctl.c
@@ -884,7 +884,9 @@  static bool check_ext_ctrls(struct v4l2_ext_controls *c, unsigned long ioctl)
 			return false;
 		break;
 	case V4L2_CTRL_WHICH_DEF_VAL:
-		/* Default value cannot be changed */
+	case V4L2_CTRL_WHICH_MIN_VAL:
+	case V4L2_CTRL_WHICH_MAX_VAL:
+		/* Default, minimum or maximum value cannot be changed */
 		if (ioctl == VIDIOC_S_EXT_CTRLS ||
 		    ioctl == VIDIOC_TRY_EXT_CTRLS) {
 			c->error_idx = c->count;
diff --git a/include/media/v4l2-ctrls.h b/include/media/v4l2-ctrls.h
index b0db167a3ac4..6e12493b30d3 100644
--- a/include/media/v4l2-ctrls.h
+++ b/include/media/v4l2-ctrls.h
@@ -133,6 +133,8 @@  struct v4l2_ctrl_ops {
  *
  * @equal: return true if all ctrl->elems array elements are equal.
  * @init: initialize the value for array elements from from_idx to ctrl->elems.
+ * @minimum: set the value to the minimum value of the control.
+ * @maximum: set the value to the maximum value of the control.
  * @log: log the value.
  * @validate: validate the value for ctrl->new_elems array elements.
  *	Return 0 on success and a negative value otherwise.
@@ -142,6 +144,10 @@  struct v4l2_ctrl_type_ops {
 		      union v4l2_ctrl_ptr ptr1, union v4l2_ctrl_ptr ptr2);
 	void (*init)(const struct v4l2_ctrl *ctrl, u32 from_idx,
 		     union v4l2_ctrl_ptr ptr);
+	void (*minimum)(const struct v4l2_ctrl *ctrl, u32 idx,
+			union v4l2_ctrl_ptr ptr);
+	void (*maximum)(const struct v4l2_ctrl *ctrl, u32 idx,
+			union v4l2_ctrl_ptr ptr);
 	void (*log)(const struct v4l2_ctrl *ctrl);
 	int (*validate)(const struct v4l2_ctrl *ctrl, union v4l2_ctrl_ptr ptr);
 };
@@ -247,6 +253,12 @@  typedef void (*v4l2_ctrl_notify_fnc)(struct v4l2_ctrl *ctrl, void *priv);
  * @p_def:	The control's default value represented via a union which
  *		provides a standard way of accessing control types
  *		through a pointer (for compound controls only).
+ * @p_min:	The control's minimum value represented via a union which
+ *		provides a standard way of accessing control types
+ *		through a pointer (for compound controls only).
+ * @p_max:	The control's maximum value represented via a union which
+ *		provides a standard way of accessing control types
+ *		through a pointer (for compound controls only).
  * @p_cur:	The control's current value represented via a union which
  *		provides a standard way of accessing control types
  *		through a pointer.
@@ -306,6 +318,8 @@  struct v4l2_ctrl {
 	} cur;
 
 	union v4l2_ctrl_ptr p_def;
+	union v4l2_ctrl_ptr p_min;
+	union v4l2_ctrl_ptr p_max;
 	union v4l2_ctrl_ptr p_new;
 	union v4l2_ctrl_ptr p_cur;
 };
@@ -425,6 +439,8 @@  struct v4l2_ctrl_handler {
  * @step:	The control's step value for non-menu controls.
  * @def:	The control's default value.
  * @p_def:	The control's default value for compound controls.
+ * @p_min:	The control's minimum value for compound controls.
+ * @p_max:	The control's maximum value for compound controls.
  * @dims:	The size of each dimension.
  * @elem_size:	The size in bytes of the control.
  * @flags:	The control's flags.
@@ -454,6 +470,8 @@  struct v4l2_ctrl_config {
 	u64 step;
 	s64 def;
 	union v4l2_ctrl_ptr p_def;
+	union v4l2_ctrl_ptr p_min;
+	union v4l2_ctrl_ptr p_max;
 	u32 dims[V4L2_CTRL_MAX_DIMS];
 	u32 elem_size;
 	u32 flags;
@@ -723,17 +741,23 @@  struct v4l2_ctrl *v4l2_ctrl_new_std_menu_items(struct v4l2_ctrl_handler *hdl,
  * @ops:       The control ops.
  * @id:        The control ID.
  * @p_def:     The control's default value.
+ * @p_min:     The control's minimum value.
+ * @p_max:     The control's maximum value.
  *
- * Sames as v4l2_ctrl_new_std(), but with support to compound controls, thanks
- * to the @p_def field. Use v4l2_ctrl_ptr_create() to create @p_def from a
- * pointer. Use v4l2_ctrl_ptr_create(NULL) if the default value of the
- * compound control should be all zeroes.
+ * Same as v4l2_ctrl_new_std(), but with support to compound controls, thanks
+ * to the @p_def/min/max fields. Use v4l2_ctrl_ptr_create() to create
+ * @p_def/min/max from a pointer. Use v4l2_ctrl_ptr_create(NULL) if the
+ * default value of the compound control should be all zeroes. Use
+ * v4l2_ctrl_ptr_create(NULL) if the min/max value of the compound control
+ * is not defined, -ENODATA will be returned in this case.
  *
  */
 struct v4l2_ctrl *v4l2_ctrl_new_std_compound(struct v4l2_ctrl_handler *hdl,
 					     const struct v4l2_ctrl_ops *ops,
 					     u32 id,
-					     const union v4l2_ctrl_ptr p_def);
+					     const union v4l2_ctrl_ptr p_def,
+					     const union v4l2_ctrl_ptr p_min,
+					     const union v4l2_ctrl_ptr p_max);
 
 /**
  * v4l2_ctrl_new_int_menu() - Create a new standard V4L2 integer menu control.
diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
index 089d553cf736..d7670aaf3b5f 100644
--- a/include/uapi/linux/videodev2.h
+++ b/include/uapi/linux/videodev2.h
@@ -1863,6 +1863,8 @@  struct v4l2_ext_controls {
 #define V4L2_CTRL_WHICH_CUR_VAL   0
 #define V4L2_CTRL_WHICH_DEF_VAL   0x0f000000
 #define V4L2_CTRL_WHICH_REQUEST_VAL 0x0f010000
+#define V4L2_CTRL_WHICH_MIN_VAL   0x0f020000
+#define V4L2_CTRL_WHICH_MAX_VAL   0x0f030000
 
 enum v4l2_ctrl_type {
 	V4L2_CTRL_TYPE_INTEGER	     = 1,
@@ -1970,6 +1972,7 @@  struct v4l2_querymenu {
 #define V4L2_CTRL_FLAG_EXECUTE_ON_WRITE	0x0200
 #define V4L2_CTRL_FLAG_MODIFY_LAYOUT	0x0400
 #define V4L2_CTRL_FLAG_DYNAMIC_ARRAY	0x0800
+#define V4L2_CTRL_FLAG_HAS_WHICH_MIN_MAX 0x1000
 
 /*  Query flags, to be ORed with the control ID */
 #define V4L2_CTRL_FLAG_NEXT_CTRL	0x80000000