RE: [PATCH v3 0/8] Add dual-LVDS panel support to EK874
Hi Laurent, Did you have any time to look into this series? Thanks, Fab > From: Fabrizio Castro > Sent: 28 August 2019 19:37 > Subject: [PATCH v3 0/8] Add dual-LVDS panel support to EK874 > > Dear All, > > this series adds support for dual-LVDS panel IDK-2121WR > from Advantech: > https://buy.advantech.eu/Displays/Embedded-LCD-Kits-High-Brightness/model-IDK-2121WR-K2FHA2E.htm > > V3 approaches the problem in a completely different way, we now > have two new properties to mark the ports in the DT as receiving > even pixels and odd pixels: dual-lvds-even-pixels and dual-lvds-odd-pixels, > which means device drivers should not use bridge specific or panel > specific dual_link flags. Also, in this case the DT describes the > connection fully. > > In order for the solution to be generic, I have exported a new helper > (drm_of_lvds_get_dual_link_configuration) to walk the device tree, > and figure out if the connection is dual-LVDS. The same helper gives > information about the configuration of the connection. If Px is connected > to a port expecting even pixels and Py is connected to a port expecting > odd pixels, then the helper returns DRM_LVDS_DUAL_LINK_EVEN_ODD_PIXELS > (like in the example below), otherwise it returns > DRM_LVDS_DUAL_LINK_ODD_EVEN_PIXELS. > > > dual-lvds-even-pixels > || || > || Px |-->| Pn || > || || > | SOURCE | dual-lvds-odd-pixels | SINK | > || || > || Py |-->| Pm || > || || > > > The device driver for the encoder then will work out if with the current > wiring the pixels need swapping or not. > > The same solution works for both panels and bridges. > > Since the DT describes the connection fully, driver > drivers/gpu/drm/panel/panel-lvds.c works out-of-the-box, no changes > required, however, this implementation opens up a problem with the > dt-bindings. > Driver drivers/gpu/drm/panel/panel-lvds.c can still be pleased by > a port node, but also by a ports node. > I have created Documentation/devicetree/bindings/display/bus-timings/lvds.yaml > with the idea of including it from panels and bridges dt-bindings > supporting dual-LVDS (and of course the dt-bindings for the specific > devices should say which port should be marked as what), but file > Documentation/devicetree/bindings/display/panel/lvds.yaml formally > requires property "port", while with this implementation it should require > OneOf "port" and "ports", and unfortunately I can't seem to find a neat way > aroud that, other than creating a new compatible string > (e.g. "panel-dual-lvds"), a new dt-binding document for it, and of course > adding > support for the new compatible string to drivers/gpu/drm/panel/panel-lvds.c. > As a result, this series is missing (at least) a patch necessary to fully > document the new implementation within > Documentation/devicetree/bindings/display/panel/lvds.yaml > > Rob, do you have any suggestions? Do you think this idea works ok from a > documentation point of view? By the way, I don't really know what I am doing > with the yaml dt-bindings, I hope you won't be horrified by this series :-P > > I hope I was able to deliver the concept clearly, if not please just ask. > > Comments are very much appreciated. > > Thanks, > Fab > > Fabrizio Castro (8): > dt-bindings: display: Add bindings for LVDS bus-timings > dt-bindings: display: Add idk-2121wr binding > drm: Add bus timings helper > drm: rcar-du: lvds: Add dual-LVDS panels support > drm: bridge: thc63: Do not report input bus mode through bridge > timings > arm64: dts: renesas: Add EK874 board with idk-2121wr display support > [HACK] arm64: dts: renesas: draak: Enable LVDS > [HACK] arm64: dts: renesas: draak: Enable LVDS dual-link operation > > .../bindings/display/bus-timings/lvds.yaml | 38 +++ > .../display/panel/advantech,idk-2121wr.yaml| 90 > arch/arm64/boot/dts/renesas/Makefile | 3 +- > .../boot/dts/renesas/r8a774c0-ek874-idk-2121wr.dts | 116 > + > arch/arm64/boot/dts/renesas/r8a77990-ebisu.dts | 21 +++- > arch/arm64/boot/dts/renesas/r8a77995-draak.dts | 26 +++-- > drivers/gpu/drm/Makefile | 3 +- > drivers/gpu/drm/bridge/thc63lvd1024.c | 9 +- > drivers/gpu/drm/drm_bus_timings.c | 97 + > drivers/gpu/drm/rcar-du/rcar_lvds.c| 110 +++ > include/drm/drm_bridge.h | 8 -- > include/drm/drm_bus_timings.h | 21 > 12 files changed, 473 insertions(+), 69 deletions(-) > create mode 100644 >
RE: [PATCH v3 0/8] Add dual-LVDS panel support to EK874
Hi Rob, Thank you for your feedback! > From: Rob Herring > Sent: 29 August 2019 16:27 > To: Fabrizio Castro > Subject: Re: [PATCH v3 0/8] Add dual-LVDS panel support to EK874 > > On Wed, Aug 28, 2019 at 1:36 PM Fabrizio Castro > wrote: > > > > Dear All, > > > > this series adds support for dual-LVDS panel IDK-2121WR > > from Advantech: > > https://buy.advantech.eu/Displays/Embedded-LCD-Kits-High-Brightness/model-IDK-2121WR-K2FHA2E.htm > > > > V3 approaches the problem in a completely different way, we now > > have two new properties to mark the ports in the DT as receiving > > even pixels and odd pixels: dual-lvds-even-pixels and dual-lvds-odd-pixels, > > which means device drivers should not use bridge specific or panel > > specific dual_link flags. Also, in this case the DT describes the > > connection fully. > > > > In order for the solution to be generic, I have exported a new helper > > (drm_of_lvds_get_dual_link_configuration) to walk the device tree, > > and figure out if the connection is dual-LVDS. The same helper gives > > information about the configuration of the connection. If Px is connected > > to a port expecting even pixels and Py is connected to a port expecting > > odd pixels, then the helper returns DRM_LVDS_DUAL_LINK_EVEN_ODD_PIXELS > > (like in the example below), otherwise it returns > > DRM_LVDS_DUAL_LINK_ODD_EVEN_PIXELS. > > > > > > dual-lvds-even-pixels > > || || > > || Px |-->| Pn || > > || || > > | SOURCE | dual-lvds-odd-pixels | SINK | > > || || > > || Py |-->| Pm || > > || || > > > > > > The device driver for the encoder then will work out if with the current > > wiring the pixels need swapping or not. > > > > The same solution works for both panels and bridges. > > > > Since the DT describes the connection fully, driver > > drivers/gpu/drm/panel/panel-lvds.c works out-of-the-box, no changes > > required, however, this implementation opens up a problem with the > > dt-bindings. > > Driver drivers/gpu/drm/panel/panel-lvds.c can still be pleased by > > a port node, but also by a ports node. > > I have created > > Documentation/devicetree/bindings/display/bus-timings/lvds.yaml > > with the idea of including it from panels and bridges dt-bindings > > supporting dual-LVDS (and of course the dt-bindings for the specific > > devices should say which port should be marked as what), but file > > Documentation/devicetree/bindings/display/panel/lvds.yaml formally > > requires property "port", while with this implementation it should require > > OneOf "port" and "ports", and unfortunately I can't seem to find a neat way > > aroud that, other than creating a new compatible string > > Just add 'ports' and drop 'port' from being required in the common > binding. Then it is up to the panel specific bindings to define which > one is required. Or we just leave it to allow either form which the > graph code can handle. > > We could have this in the common binding: > > oneOf: > - required: [ports] > - required: [port] Thank you for Rob for looking into this. I will wait for a feedback from Laurent on the code before sending out v4. Thanks, Fab > > Rob
Re: [PATCH v3 0/8] Add dual-LVDS panel support to EK874
On Wed, Aug 28, 2019 at 1:36 PM Fabrizio Castro wrote: > > Dear All, > > this series adds support for dual-LVDS panel IDK-2121WR > from Advantech: > https://buy.advantech.eu/Displays/Embedded-LCD-Kits-High-Brightness/model-IDK-2121WR-K2FHA2E.htm > > V3 approaches the problem in a completely different way, we now > have two new properties to mark the ports in the DT as receiving > even pixels and odd pixels: dual-lvds-even-pixels and dual-lvds-odd-pixels, > which means device drivers should not use bridge specific or panel > specific dual_link flags. Also, in this case the DT describes the > connection fully. > > In order for the solution to be generic, I have exported a new helper > (drm_of_lvds_get_dual_link_configuration) to walk the device tree, > and figure out if the connection is dual-LVDS. The same helper gives > information about the configuration of the connection. If Px is connected > to a port expecting even pixels and Py is connected to a port expecting > odd pixels, then the helper returns DRM_LVDS_DUAL_LINK_EVEN_ODD_PIXELS > (like in the example below), otherwise it returns > DRM_LVDS_DUAL_LINK_ODD_EVEN_PIXELS. > > > dual-lvds-even-pixels > || || > || Px |-->| Pn || > || || > | SOURCE | dual-lvds-odd-pixels | SINK | > || || > || Py |-->| Pm || > || || > > > The device driver for the encoder then will work out if with the current > wiring the pixels need swapping or not. > > The same solution works for both panels and bridges. > > Since the DT describes the connection fully, driver > drivers/gpu/drm/panel/panel-lvds.c works out-of-the-box, no changes > required, however, this implementation opens up a problem with the > dt-bindings. > Driver drivers/gpu/drm/panel/panel-lvds.c can still be pleased by > a port node, but also by a ports node. > I have created Documentation/devicetree/bindings/display/bus-timings/lvds.yaml > with the idea of including it from panels and bridges dt-bindings > supporting dual-LVDS (and of course the dt-bindings for the specific > devices should say which port should be marked as what), but file > Documentation/devicetree/bindings/display/panel/lvds.yaml formally > requires property "port", while with this implementation it should require > OneOf "port" and "ports", and unfortunately I can't seem to find a neat way > aroud that, other than creating a new compatible string Just add 'ports' and drop 'port' from being required in the common binding. Then it is up to the panel specific bindings to define which one is required. Or we just leave it to allow either form which the graph code can handle. We could have this in the common binding: oneOf: - required: [ports] - required: [port] Rob
