From: Dave Stevenson <dave.stevenson@raspberrypi.com>
To: Benjamin Bara <bbara93@gmail.com>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>,
Manivannan Sadhasivam <mani@kernel.org>,
laurent.pinchart@ideasonboard.com, jacopo.mondi@ideasonboard.com,
linux-media@vger.kernel.org, linux-kernel@vger.kernel.org,
Benjamin Bara <benjamin.bara@skidata.com>
Subject: Re: [PATCH 1/2] media: uapi: Add V4L2_CID_VTOTAL control
Date: Fri, 9 Jun 2023 15:03:46 +0100 [thread overview]
Message-ID: <CAPY8ntDsUPZvN0M_7pyRfERK9V0MCkD6pp7zu6G9nDWYHwSVcw@mail.gmail.com> (raw)
In-Reply-To: <20230609-v4l2-vtotal-v1-1-4b7dee7e073e@skidata.com>
Hi Benjamin
Thanks for the patch.
On Fri, 9 Jun 2023 at 14:16, Benjamin Bara <bbara93@gmail.com> wrote:
>
> From: Benjamin Bara <benjamin.bara@skidata.com>
>
> Currently, V4L2_CID_VBLANK can be used to control the frame duration of
> a stream. However, camera sensors usually have a register for the
> vertical total size (image data + blanking), e.g. VMAX on the imx290.
> The dependency between format height and vertical blanking results to a
> change of the vertical blanking value and limits whenever the format of
> the frame is changed and therefore makes it harder for user space to do
> calculations, e.g. the frame duration.
>
> V4L2_CID_VTOTAL does not depend on the format and therefore simplifies
> calculations. Additionally, it represents the hardware "better" and
> therefore also simplifies calculations on the driver side.
>
> Signed-off-by: Benjamin Bara <benjamin.bara@skidata.com>
> ---
> Documentation/userspace-api/media/v4l/ext-ctrls-image-source.rst | 6 ++++++
> drivers/media/v4l2-core/v4l2-ctrls-defs.c | 1 +
> include/uapi/linux/v4l2-controls.h | 1 +
> 3 files changed, 8 insertions(+)
>
> diff --git a/Documentation/userspace-api/media/v4l/ext-ctrls-image-source.rst b/Documentation/userspace-api/media/v4l/ext-ctrls-image-source.rst
> index 71f23f131f97..e72d1363ad85 100644
> --- a/Documentation/userspace-api/media/v4l/ext-ctrls-image-source.rst
> +++ b/Documentation/userspace-api/media/v4l/ext-ctrls-image-source.rst
> @@ -59,6 +59,12 @@ Image Source Control IDs
> non-sensitive.
> This control is required for automatic calibration of sensors/cameras.
>
> +``V4L2_CID_VTOTAL (integer)``
> + Number of total lines per frame, including data and idle lines (blanking).
> + The unit of the vertical total size is a line. Every line has length of the
> + image width plus horizontal blanking at the pixel rate defined by
> + ``V4L2_CID_PIXEL_RATE`` control in the same sub-device.
> +
> .. c:type:: v4l2_area
>
> .. flat-table:: struct v4l2_area
The documentation for Frame interval configuration on Raw camera
sensors[1] needs updating to describe the new behaviour as well.
Dave
[1] https://elixir.bootlin.com/linux/latest/source/Documentation/driver-api/media/camera-sensor.rst#L80
> diff --git a/drivers/media/v4l2-core/v4l2-ctrls-defs.c b/drivers/media/v4l2-core/v4l2-ctrls-defs.c
> index 564fedee2c88..6a0d310d5f42 100644
> --- a/drivers/media/v4l2-core/v4l2-ctrls-defs.c
> +++ b/drivers/media/v4l2-core/v4l2-ctrls-defs.c
> @@ -1112,6 +1112,7 @@ const char *v4l2_ctrl_get_name(u32 id)
> case V4L2_CID_TEST_PATTERN_BLUE: return "Blue Pixel Value";
> case V4L2_CID_TEST_PATTERN_GREENB: return "Green (Blue) Pixel Value";
> case V4L2_CID_NOTIFY_GAINS: return "Notify Gains";
> + case V4L2_CID_VTOTAL: return "Vertical Total Size";
>
> /* Image processing controls */
> /* Keep the order of the 'case's the same as in v4l2-controls.h! */
> diff --git a/include/uapi/linux/v4l2-controls.h b/include/uapi/linux/v4l2-controls.h
> index 5e80daa4ffe0..99120005634e 100644
> --- a/include/uapi/linux/v4l2-controls.h
> +++ b/include/uapi/linux/v4l2-controls.h
> @@ -1117,6 +1117,7 @@ enum v4l2_jpeg_chroma_subsampling {
> #define V4L2_CID_TEST_PATTERN_GREENB (V4L2_CID_IMAGE_SOURCE_CLASS_BASE + 7)
> #define V4L2_CID_UNIT_CELL_SIZE (V4L2_CID_IMAGE_SOURCE_CLASS_BASE + 8)
> #define V4L2_CID_NOTIFY_GAINS (V4L2_CID_IMAGE_SOURCE_CLASS_BASE + 9)
> +#define V4L2_CID_VTOTAL (V4L2_CID_IMAGE_SOURCE_CLASS_BASE + 10)
>
>
> /* Image processing controls */
>
> --
> 2.34.1
>
next prev parent reply other threads:[~2023-06-09 14:04 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-09 13:15 [PATCH 0/2] media: uapi: Add V4L2_CID_VTOTAL control Benjamin Bara
2023-06-09 13:15 ` [PATCH 1/2] " Benjamin Bara
2023-06-09 14:03 ` Dave Stevenson [this message]
2023-06-09 13:15 ` [PATCH 2/2] media: i2c: imx290: Add support for V4L2_CID_VTOTAL Benjamin Bara
2023-06-09 14:21 ` Dave Stevenson
2023-06-09 14:56 ` Benjamin Bara
2023-06-09 15:41 ` Dave Stevenson
2023-06-23 23:28 ` Laurent Pinchart
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