Re: [RFC PATCH V0 0/2] media: v4l2: extend framework to support advanced feature of Mediatek Camsys driver

[Sakari Ailus <sakari.ailus@iki.fi>]

Hi John,

On Fri, May 07, 2021 at 10:53:35AM +0800, john.wei@mediatek.com wrote:
> Hello,
> 
> This is the first version of the RFC patch series to v4l2 and media framework
> to support virtual channel (an advanced feature of MIPI CSI). Virtual channel
> was used commonly among modern image sensor. It was used to transfer
> metadata of an image such as statistical data of AE or AF.Some advanced
> features of camera such as HDR (High dynamic range), PDAF (Phase Detection
> Auto Focus) were achieved by virtual channel. Medaitek made some modification
> to frame descriptor based on https://patchwork.kernel.org/patch/10875875/ and
> https://patchwork.kernel.org/patch/10875875/.We extend the struct
> v4l2_mbus_frame_desc_entry by add enable, hsize, vsize and user_data_desc.
> With this modification, frame descriptor are now more powerful to meet all
> kinds of need among different applications. Here is an example that we use
> frame descriptor to describe all data streams in a frame output by a
>  stagger sensor.

Thanks for your e-mail.

Work has been done to address the problem area previously but it hasn't
reached upstream yet.

Tomi Valkeinen has posted a set here:

<https://lore.kernel.org/linux-media/20210427124523.990938-1-tomi.valkeinen@ideasonboard.com/>

Cc Tomi as well.

> 
> static struct v4l2_mbus_frame_desc_entry frame_desc_cus1[] = {
>         {
>                 .bus.csi2 = {
>                         .channel = 0,
>                         .data_type = 0x2b,
>                         .enable = 1,
>                         .hsize = 0xF00,
>                         .vsize = 0x870,
>                         .user_data_desc = V4L2_MBUS_CSI2_USER_DEFINED_DATA_DESC_HDR_LE,
>                 },
>         },
>         {
>                 .bus.csi2 = {
>                         .channel = 1,
>                         .data_type = 0x2b,
>                         .enable = 1,
>                         .hsize = 0xF00,
>                         .vsize = 0x870,
>                         .user_data_desc = V4L2_MBUS_CSI2_USER_DEFINED_DATA_DESC_HDR_SE,
>                 },
>         },
> };
> 
> The first data stream, data for long exposure was transfer by channel 0 with
> data type 0x2b and the resolution was 0xF00 by horizontal and 0x870 by vertical.
> The second data stream, data for short exposure was transfer by channel 1
> with data type 0x2b and the resolution was also 0xF00 by horizontal and 0x870
> by vertical. Both long exposure and short exposure data will be fused in ISP
> stage to output a HDR image.
> 
>   media: v4l2: Add fields to frame descriptors
>   media: v4l2-ctrl: Add user defined base for ISP user control
> 
>  include/media/v4l2-subdev.h        |   25 ++++++++++++++++++++++++-
>  include/uapi/linux/v4l2-controls.h |   10 ++++++++++
>  2 files changed, 34 insertions(+), 1 deletion(-)
> 

-- 
Kind regards,

Sakari Ailus

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