[PATCH v2 02/10] dt-bindings: display: bridge: thc63lvd1024: Document dual-link operation

[Laurent Pinchart]

Hi Geert,

On Sun, May 12, 2019 at 10:58:54AM +0200, Geert Uytterhoeven wrote:
> On Sat, May 11, 2019 at 11:07 PM Laurent Pinchart wrote:
> > The THC63LVD1024 LVDS decoder can operate in two modes, single-link or
> > dual-link. In dual-link mode both input ports are used to carry even-
> > and odd-numbered pixels separately. Document this in the DT bindings,
> > along with the related rules governing port and usage.
> >
> > Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas at ideasonboard.com>
> > Reviewed-by: Jacopo Mondi <jacopo+renesas at jmondi.org>
> > ---
> >  .../bindings/display/bridge/thine,thc63lvd1024.txt          | 6 ++++++
> >  1 file changed, 6 insertions(+)
> >
> > diff --git a/Documentation/devicetree/bindings/display/bridge/thine,thc63lvd1024.txt b/Documentation/devicetree/bindings/display/bridge/thine,thc63lvd1024.txt
> > index 37f0c04d5a28..d17d1e5820d7 100644
> > --- a/Documentation/devicetree/bindings/display/bridge/thine,thc63lvd1024.txt
> > +++ b/Documentation/devicetree/bindings/display/bridge/thine,thc63lvd1024.txt
> > @@ -28,6 +28,12 @@ Optional video port nodes:
> >  - port at 1: Second LVDS input port
> >  - port at 3: Second digital CMOS/TTL parallel output
> >
> > +The device can operate in single-link mode or dual-link mode. In single-link
> > +mode, all pixels are received on port at 0, and port at 1 shall not contain any
> > +endpoint. In dual-link mode, even-numbered pixels are received on port at 0 and
> > +odd-numbered pixels on port at 1, and both port at 0 and port at 1 shall contain
> > +endpoints.
> 
> This describes single/dual input.
> Does single/dual output need to be described, too?

Jacopo asked the same question on v1 :-) Dual-output should be described
as well, but as I have no hardware setup where to test that, I decided
to leave it out of the DT bindings to start with, as it's generally a
bad idea to specify untested DT bindings (as in having no end-to-end
implementation). I don't think it will be a big deal though, there is
already a port for the second output, it should just be a matter of
connecting it.

> BTW, I see the second input/output set is optional, wile the first set
> is required.  Could it happen the hardware is wired for the second
> set only?

Not to my knowledge. In dual-in, dual-out the two input/output pairs are
not independent, the two inputs are used together to create a higher
bandwidth link, and the odd- and even-pixels are then sent to separate
routes.

-- 
Regards,

Laurent Pinchart