| Message ID | 1564731249-22671-3-git-send-email-fabrizio.castro@bp.renesas.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Kieran Bingham |
| Headers | show |
| Series | Add dual-LVDS panel support to EK874 | expand |
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:
Hi Laurent, Thank you for your feedback! > From: Laurent Pinchart <laurent.pinchart@ideasonboard.com> > Sent: 02 August 2019 08:44 > Subject: Re: [PATCH/RFC 02/12] dt-bindings: display: renesas: lvds: Document renesas,swap-data > > 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 ? Yes, that would be my preference too, and it would be better, I am just not entirely what's the best place for this information though > 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. Isn't drm_bridge_timings specific for bridges? Thanks! Fab > > > > > > > Example: > > -- > Regards, > > Laurent Pinchart
Hi Fabrizio, On Mon, Aug 05, 2019 at 08:59:51AM +0000, Fabrizio Castro wrote: > > From: Laurent Pinchart <laurent.pinchart@ideasonboard.com> > > Sent: 02 August 2019 08:44 > > Subject: Re: [PATCH/RFC 02/12] dt-bindings: display: renesas: lvds: Document renesas,swap-data > > > > 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 ? > > Yes, that would be my preference too, and it would be better, I am just not entirely > what's the best place for this information though > > > 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. > > Isn't drm_bridge_timings specific for bridges? Its name makes it specific to bridges, but the information it contains could equally apply to panels. I would thus use it for both, possibly after renaming it.
Hi Laurent, > From: linux-kernel-owner@vger.kernel.org <linux-kernel-owner@vger.kernel.org> On Behalf Of Laurent Pinchart > Sent: 05 August 2019 10:36 > Subject: Re: [PATCH/RFC 02/12] dt-bindings: display: renesas: lvds: Document renesas,swap-data > > Hi Fabrizio, > > On Mon, Aug 05, 2019 at 08:59:51AM +0000, Fabrizio Castro wrote: > > > From: Laurent Pinchart <laurent.pinchart@ideasonboard.com> > > > Sent: 02 August 2019 08:44 > > > Subject: Re: [PATCH/RFC 02/12] dt-bindings: display: renesas: lvds: Document renesas,swap-data > > > > > > 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 ? > > > > Yes, that would be my preference too, and it would be better, I am just not entirely > > what's the best place for this information though > > > > > 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. > > > > Isn't drm_bridge_timings specific for bridges? > > Its name makes it specific to bridges, but the information it contains > could equally apply to panels. I would thus use it for both, possibly > after renaming it. Will give this a try then. Thanks, Fab > > -- > Regards, > > Laurent Pinchart
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. Example:
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(+)