Re: [PATCH v3 04/10] dt-bindings: display: renesas: lvds: Add renesas, companion property

[Sam Ravnborg <sam@ravnborg.org>]

Hi Laurent.

> > >  
> > > +Optional properties:
> > > +
> > > +- renesas,companion : phandle to the companion LVDS encoder. This property is
> > > +  mandatory for the first LVDS encoder on D3 and E3 SoCs, and shall point to
> > > +  the second encoder to be used as a companion in dual-link mode. It shall not
> > > +  be set for any other LVDS encoder.
> > 
> > If the D3 and E3 socs do not mandate the use of dual-link, then what to
> > do in the DT? Because according to the above this property must be
> > specified for D3 and E3 SOC's.
> 
> This property doesn't enable dual-link mode, it only specifies the
> companion LVDS encoder used for dual-link mode, when enabled (through
> communication between the LVDS encoder and the LVDS receiver at
> runtime).
> 
> Jacopo had a similar comment so I suppose this isn't clear. How would
> you word it to make it clear ?
Let me try:


- renesas,companion : phandle to the companion LVDS encoder. This property is
  mandatory for the first LVDS encoder on D3 and E3 SoCs when dual-link mode
  is supported.
  The property shall pont to the phandle of the second encoder to be used as a
  companion in dual-link mode. It shall not be set for any other LVDS encoder.

The main difference is "when dual-link mode is supported".
As per my understanding this property is only relevant when the actual
HW supports / uses dual-link mode.
So for a board that do not even wire up dual-link, then setting the
property would be confusing.

I hope this better describes my understanding.

	Sam
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