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

[Hans Verkuil]

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