On 09/25/2018 12:14 PM, Sakari Ailus wrote:
> Add support for exponential bases, prefixes as well as units for V4L2
> controls. This makes it possible to convey information on the relation
> between the control value and the hardware feature being controlled.
>
> Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
> ---
> include/uapi/linux/videodev2.h | 32 +++++++++++++++++++++++++++++++-
> 1 file changed, 31 insertions(+), 1 deletion(-)
>
> diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
> index ae083978988f1..23b02f2db85a1 100644
> --- a/include/uapi/linux/videodev2.h
> +++ b/include/uapi/linux/videodev2.h
> @@ -1652,6 +1652,32 @@ struct v4l2_queryctrl {
> __u32 reserved[2];
> };
>
> +/* V4L2 control exponential bases */
> +#define V4L2_CTRL_BASE_UNDEFINED 0
> +#define V4L2_CTRL_BASE_LINEAR 1
I'm not really sure you need BASE_LINEAR. That is effectively the same
as UNDEFINED since what else can you do? It's also weird to have this
as 'base' if the EXPONENTIAL flag is set.
I don't see why you need the EXPONENTIAL flag at all: if this is non-0,
then you know the exponential base.
> +#define V4L2_CTRL_BASE_2 2
> +#define V4L2_CTRL_BASE_10 10
> +
> +/* V4L2 control unit prefixes */
> +#define V4L2_CTRL_PREFIX_NANO -9
> +#define V4L2_CTRL_PREFIX_MICRO -6
> +#define V4L2_CTRL_PREFIX_MILLI -3
> +#define V4L2_CTRL_PREFIX_1 0
I would prefer PREFIX_NONE, since there is no prefix in this case.
I assume this prefix is only valid if the unit is not UNDEFINED and not
NONE?
Is 'base' also dependent on a valid unit? (it doesn't appear to be)
> +#define V4L2_CTRL_PREFIX_KILO 3
> +#define V4L2_CTRL_PREFIX_MEGA 6
> +#define V4L2_CTRL_PREFIX_GIGA 9
> +
> +/* V4L2 control units */
> +#define V4L2_CTRL_UNIT_UNDEFINED 0
> +#define V4L2_CTRL_UNIT_NONE 1
> +#define V4L2_CTRL_UNIT_SECOND 2
> +#define V4L2_CTRL_UNIT_AMPERE 3
> +#define V4L2_CTRL_UNIT_LINE 4
> +#define V4L2_CTRL_UNIT_PIXEL 5
> +#define V4L2_CTRL_UNIT_PIXELS_PER_SEC 6
> +#define V4L2_CTRL_UNIT_HZ 7
> +
> +
> /* Used in the VIDIOC_QUERY_EXT_CTRL ioctl for querying extended controls */
> struct v4l2_query_ext_ctrl {
> __u32 id;
> @@ -1666,7 +1692,10 @@ struct v4l2_query_ext_ctrl {
> __u32 elems;
> __u32 nr_of_dims;
> __u32 dims[V4L2_CTRL_MAX_DIMS];
> - __u32 reserved[32];
> + __u8 base;
> + __s8 prefix;
> + __u16 unit;
> + __u32 reserved[31];
> };
>
> /* Used in the VIDIOC_QUERYMENU ioctl for querying menu items */
> @@ -1692,6 +1721,7 @@ struct v4l2_querymenu {
> #define V4L2_CTRL_FLAG_HAS_PAYLOAD 0x00000100
> #define V4L2_CTRL_FLAG_EXECUTE_ON_WRITE 0x00000200
> #define V4L2_CTRL_FLAG_MODIFY_LAYOUT 0x00000400
> +#define V4L2_CTRL_FLAG_EXPONENTIAL 0x00000800
>
> /* Query flags, to be ORed with the control ID */
> #define V4L2_CTRL_FLAG_NEXT_CTRL 0x80000000
>
Regards,
Hans
