Messages in this thread | | | Date | Fri, 2 Aug 2019 10:44:28 +0300 | From | Laurent Pinchart <> | Subject | Re: [PATCH/RFC 02/12] dt-bindings: display: renesas: lvds: Document renesas,swap-data |
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Hi Fabrizio,
Thank you for the patch.
On Fri, Aug 02, 2019 at 08:33:59AM +0100, Fabrizio Castro wrote: > R-Car D3, R-Car E3, and RZ/G2E support dual-link mode. > In such a mode, the first LVDS encoder emits even data, and the > second LVDS encoder emits odd data. This patch documents property > renesas,swap-data, used to swap even and odd data around. > > Signed-off-by: Fabrizio Castro <fabrizio.castro@bp.renesas.com> > --- > Documentation/devicetree/bindings/display/bridge/renesas,lvds.txt | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/Documentation/devicetree/bindings/display/bridge/renesas,lvds.txt b/Documentation/devicetree/bindings/display/bridge/renesas,lvds.txt > index dece79e..8980179 100644 > --- a/Documentation/devicetree/bindings/display/bridge/renesas,lvds.txt > +++ b/Documentation/devicetree/bindings/display/bridge/renesas,lvds.txt > @@ -52,6 +52,11 @@ Optional properties: > mandatory for the first LVDS encoder on R-Car D3, R-Car E3, and RZ/G2E 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. > +- renesas,swap-data : when in dual-link mode, the first LVDS encoder normally > + emits even data, and the second LVDS encoder emits odd data. When property > + renesas,swap-data is specified, the data emitted by the two encoders will be > + swapped around. This property can only be used in conjunction with property > + renesas,companion.
From an LVDS encoder point of view this is more a configuration option than a description of the hardware. Wouldn't it be better for the LVDS sink to report which of the odd or even pixels it expects on each of its endpoints ? The LVDS encoder driver could then query that at runtime and configure itself accordingly. Ideally this should be queried through the drm_bridge_timings structure (or through a similar mean), not through DT. An LVDS sink that has a fixed mapping of odd/even pixels to endpoints wouldn't need the information to be specified in DT at all.
> > > Example:
-- Regards,
Laurent Pinchart
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