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Date:   Mon, 12 Jun 2023 10:51:04 +0200
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Subject: Re: [RESEND PATCH v6 1/1] Added Digiteq Automotive MGB4 driver
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To:     =?UTF-8?Q?Martin_T=c5=afma?= <tumic@gpxsee.org>,
        Mauro Carvalho Chehab <mchehab@kernel.org>
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From:   Hans Verkuil <hverkuil-cisco@xs4all.nl>
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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.

Regards,

	Hans