Re: [RESEND PATCH v6 1/1] Added Digiteq Automotive MGB4 driver

[Martin Tůma]

On 12. 06. 23 10:51, Hans Verkuil wrote:
> On 08/06/2023 17:30, Martin Tůma wrote:
> > On 08. 06. 23 12:23, Hans Verkuil wrote:
> >
> > > Can you make a list of which sysfs properties correspond to existing V4L2
> > > format or timing fields and which are 'new'?
> >
> > On the left all the current mgb4 sysfs properties (see the admin-guide doc from the patch for description), on the right v4l2 structures where they could be mapped (may not be true for all of them in
> > the patch, I will check it and update the code in v7)
> >
> >
> > --- PCIE CARD ---
> >
> > module_type        -
> > module_version        -
> > fw_type            -
> > fw_version        -
> > serial_number        -
> > temperature        hwmon
> >
> > --- INPUTS ---
> >
> > input_id        -
> > oldi_lane_width        -
> > color_mapping        -
> > link_status        v4l2_input.status (V4L2_IN_ST_NO_SYNC)
> > stream_status        v4l2_input.status (V4L2_IN_ST_NO_SIGNAL)
> > video_width        v4l2_bt_timings.width
> > video_height        v4l2_bt_timings.height
> > vsync_status        v4l2_bt_timings.polarities
> > hsync_status        v4l2_bt_timings.polarities
> > vsync_gap_length    -
> > hsync_gap_length    -
> > pclk_frequency        v4l2_bt_timings.pixelclock
> > hsync_width        v4l2_bt_timings.hsync
> > vsync_width        v4l2_bt_timings.vsync
> > hback_porch        v4l2_bt_timings.hbackporch
> > hfront_porch        v4l2_bt_timings.hfrontporch
> > vback_porch        v4l2_bt_timings.vbackporch
> > vfront_porch        v4l2_bt_timings.vfrontporch
> > frequency_range        -
> > alignment        v4l2_pix_format.bytesperline
> > fpdl3_input_width    -
> > gmsl_mode        -
> > gmsl_stream_id        -
> > gmsl_fec        -
> >
> > --- OUTPUTS ---
> >
> > output_id        -
> > video_source        -
> > display_width        v4l2_bt_timings.width
> > display_height        v4l2_bt_timings.height
> > frame_rate        v4l2_frmivalenum
>
> The frame rate is a property of the width/height+blanking and the
> pixel clock frequency. IMHO it does not make sense to have this as
> a writable property. Read-only is OK.
>
> > hsync_polarity        v4l2_bt_timings.polarities
> > vsync_polarity        v4l2_bt_timings.polarities
> > de_polarity        -
> > pclk_frequency        v4l2_bt_timings.pixelclock
> > hsync_width        v4l2_bt_timings.hsync
> > vsync_width        v4l2_bt_timings.vsync
> > vsync_width        v4l2_bt_timings.vsync
> > hback_porch        v4l2_bt_timings.hbackporch
> > hfront_porch        v4l2_bt_timings.hfrontporch
> > vback_porch        v4l2_bt_timings.vbackporch
> > vfront_porch        v4l2_bt_timings.vfrontporch
> > alignment        v4l2_pix_format.bytesperline
> > fpdl3_output_width    -
> >
> >
> > M.
>
> The property I am most concerned with is alignment (both for input and output).
> But it is not clear to me what the use-case is.

Hi,
The use-case is to provide the alignment required by some video 
processing chips. We have a product based on NVIDIA Jetson TX2 that uses 
the mgb4 cards and the HW video encoding needs a specific alignment to 
work.

M.

> Regards,
>
> 	Hans