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Re: [PATCH v6 2/3] media: i2c: adv748x: add adv748x driver

From Hans Verkuil <hverkuil@xs4all.nl>
Newsgroups linux.kernel
Subject Re: [PATCH v6 2/3] media: i2c: adv748x: add adv748x driver
Date 2017-07-03 17:00 +0200
Message-ID <tZaZu-2UC-83@gated-at.bofh.it> (permalink)
References <tX0hP-2f9-5@gated-at.bofh.it> <tX0hQ-2f9-25@gated-at.bofh.it> <tZa3o-2gz-23@gated-at.bofh.it> <tZaPP-2Pz-79@gated-at.bofh.it>
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On 07/03/2017 04:45 PM, Kieran Bingham wrote:
>>> +#define ADV748X_HDMI_MAX_PIXELCLOCK    162000000
>>
>> You probably based that on the 1600x1200p60 format?
> 
> No idea I'm afraid - it's the value that was set when I recieved the driver...
> 
>>
>> 162MHz is a bit low for an adv receiver. The adv7604 and adv8742 have a max rate
>> of 225 MHz.
>> This should be documented in the datasheet.
> 
> Hrm ... haven't found it yet - I'll keep digging....

This is often documented in the hardware datasheet, not the programming datasheet.

>>> +static void adv748x_hdmi_fill_format(struct adv748x_hdmi *hdmi,
>>> +                     struct v4l2_mbus_framefmt *fmt)
>>> +{
>>> +    memset(fmt, 0, sizeof(*fmt));
>>> +
>>> +    fmt->code = MEDIA_BUS_FMT_RGB888_1X24;
>>> +    fmt->field = hdmi->timings.bt.interlaced ?
>>> +        V4L2_FIELD_INTERLACED : V4L2_FIELD_NONE;
>>
>> INTERLACED -> ALTERNATE.
> 
> OK.
> 
> OOI: Is this because of the removal of the interlaced cap - or because
> V4L2_FIELD_INTERLACED is deprecated or such?

Unless the adv748x has a deinterlacer you will receive the fields as separate
transfers.

FIELD_INTERLACED means that the two fields are combined into a single frame, but
I doubt that that's what happens. FIELD_ALTERNATE means that the top and bottom
fields are send one after the other.

FIELD_INTERLACED is very common for SDTV, but FIELD_ALTERNATE is almost always
used for HDTV.

That reminds me: in adv748x_afe_fill_format you also set FIELD_INTERLACED, but
is that correct? Shouldn't that also be FIELD_ALTERNATE?

> 
>>> +
>>> +    /* The colorspace depends on the AVI InfoFrame contents */

Missed that in the first review: add a 'TODO:' before this comment.

>>> +    fmt->colorspace = V4L2_COLORSPACE_SRGB;
>>> +
>>> +    fmt->width = hdmi->timings.bt.width;
>>> +    fmt->height = hdmi->timings.bt.height;
>>> +}

Regards,

	Hans

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Thread

[PATCH v6 0/3] ADV748x HDMI/Analog video receiver Kieran Bingham <kbingham@kernel.org> - 2017-06-27 17:10 +0200
  [PATCH v6.1 1/3] media: adv748x: Add adv7481, adv7482 bindings Kieran Bingham <kbingham@kernel.org> - 2017-06-29 12:00 +0200
  Re: [PATCH v6 2/3] media: i2c: adv748x: add adv748x driver Hans Verkuil <hverkuil@xs4all.nl> - 2017-07-03 16:00 +0200
    Re: [PATCH v6 2/3] media: i2c: adv748x: add adv748x driver Hans Verkuil <hverkuil@xs4all.nl> - 2017-07-03 17:00 +0200
    Re: [PATCH v6 2/3] media: i2c: adv748x: add adv748x driver Kieran Bingham <kieran.bingham+renesas@ideasonboard.com> - 2017-07-03 17:10 +0200
      Re: [PATCH v6 2/3] media: i2c: adv748x: add adv748x driver Hans Verkuil <hverkuil@xs4all.nl> - 2017-07-03 18:30 +0200

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