[RFC] [media] imx: assume MEDIA_ENT_F_ATV_DECODER entities output video on pad 1

[Philipp Zabel]

On Tue, 2017-04-04 at 15:11 -0700, Steve Longerbeam wrote:
> 
> On 03/30/2017 10:25 AM, Philipp Zabel wrote:
> > The TVP5150 DT bindings specify a single output port (port 0) that
> > corresponds to the video output pad (pad 1, DEMOD_PAD_VID_OUT).
> >
> > Signed-off-by: Philipp Zabel <p.zabel at pengutronix.de>
> > ---
> > I'm trying to get this to work with a TVP5150 analog TV decoder, and the
> > first problem is that this device doesn't have pad 0 as its single
> > output pad. Instead, as a MEDIA_ENT_F_ATV_DECODER entity, it has for
> > pads (input, video out, vbi out, audio out), and video out is pad 1,
> > whereas the device tree only defines a single port (0).
> 
> Shouldn't the DT bindings define ports for these other pads?

In this case, probably yes for the input pad, certainly no for the
VBI/audio pads. See the other mail.

> I haven't seen this documented anywhere, but shouldn't there
> be a 1:1 correspondence between DT ports and media pads?

Not in general. But imagine a dual HDMI->CSI2 converter, for example. We
don't support this yet, but that might reasonably be described in the
device tree as a single device with two output ports. But the internal
representation would be two completely separate v4l2 subdevices.

regards
Philipp