From: Fabrizio Castro <fabrizio.castro@bp.renesas.com>
To: Rob Herring <robh+dt@kernel.org>,
Laurent Pinchart <Laurent.pinchart@ideasonboard.com>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>,
David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>,
Mark Rutland <mark.rutland@arm.com>,
Thierry Reding <thierry.reding@gmail.com>,
Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
Maxime Ripard <maxime.ripard@bootlin.com>,
Sean Paul <sean@poorly.run>, Andrzej Hajda <a.hajda@samsung.com>,
Sam Ravnborg <sam@ravnborg.org>,
Simon Horman <horms@verge.net.au>,
Magnus Damm <magnus.damm@gmail.com>,
Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>,
dri-devel <dri-devel@lists.freedesktop.org>,
"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"open list:MEDIA DRIVERS FOR RENESAS - FCP"
<linux-renesas-soc@vger.kernel.org>,
Chris Paterson <Chris.Paterson2@renesas.com>,
Biju Das <biju.das@bp.renesas.com>,
Jacopo Mondi <jacopo+renesas@jmondi.org>,
"xu_shunji@hoperun.com" <xu_shunji@hoperun.com>,
"ebiharaml@si-linux.co.jp" <ebiharaml@si-linux.co.jp>
Subject: RE: [PATCH v3 0/8] Add dual-LVDS panel support to EK874
Date: Mon, 2 Sep 2019 10:01:01 +0000 [thread overview]
Message-ID: <TY1PR01MB17700DA7BEC8DA3AA32BEA53C0BE0@TY1PR01MB1770.jpnprd01.prod.outlook.com> (raw)
In-Reply-To: <CAL_Jsq+5FMHK4W4UQU24g+rm3CLjnhRcB29skygRB++GaJyM0A@mail.gmail.com>
Hi Rob,
Thank you for your feedback!
> From: Rob Herring <robh+dt@kernel.org>
> Sent: 29 August 2019 16:27
> To: Fabrizio Castro <fabrizio.castro@bp.renesas.com>
> Subject: Re: [PATCH v3 0/8] Add dual-LVDS panel support to EK874
>
> On Wed, Aug 28, 2019 at 1:36 PM Fabrizio Castro
> <fabrizio.castro@bp.renesas.com> 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
next prev parent reply other threads:[~2019-09-02 10:01 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-28 18:36 [PATCH v3 0/8] Add dual-LVDS panel support to EK874 Fabrizio Castro
2019-08-28 18:36 ` [PATCH v3 1/8] dt-bindings: display: Add bindings for LVDS bus-timings Fabrizio Castro
2019-08-29 7:57 ` Geert Uytterhoeven
2019-08-29 9:14 ` Fabrizio Castro
2019-08-29 14:03 ` Rob Herring
2019-08-29 14:38 ` Fabrizio Castro
2019-11-07 18:00 ` Laurent Pinchart
2019-12-06 15:11 ` Fabrizio Castro
2019-12-06 15:10 ` Fabrizio Castro
2019-08-28 18:36 ` [PATCH v3 2/8] dt-bindings: display: Add idk-2121wr binding Fabrizio Castro
2019-11-07 18:12 ` Laurent Pinchart
2019-12-06 15:17 ` Fabrizio Castro
2019-08-28 18:36 ` [PATCH v3 3/8] drm: Add bus timings helper Fabrizio Castro
2019-11-07 19:26 ` Laurent Pinchart
2019-11-07 19:30 ` Daniel Vetter
2019-12-06 15:25 ` Fabrizio Castro
2019-12-06 15:24 ` Fabrizio Castro
2019-08-28 18:36 ` [PATCH v3 4/8] drm: rcar-du: lvds: Add dual-LVDS panels support Fabrizio Castro
2019-11-07 19:50 ` Laurent Pinchart
2019-12-06 15:35 ` Fabrizio Castro
2019-08-28 18:36 ` [PATCH v3 5/8] drm: bridge: thc63: Do not report input bus mode through bridge timings Fabrizio Castro
2019-11-07 19:52 ` Laurent Pinchart
2019-12-06 15:38 ` Fabrizio Castro
2019-08-28 18:36 ` [PATCH v3 6/8] arm64: dts: renesas: Add EK874 board with idk-2121wr display support Fabrizio Castro
2019-11-07 19:55 ` Laurent Pinchart
2019-08-28 18:36 ` [PATCH v3 7/8] [HACK] arm64: dts: renesas: draak: Enable LVDS Fabrizio Castro
2019-11-07 19:57 ` Laurent Pinchart
2019-12-06 15:40 ` Fabrizio Castro
2019-08-28 18:36 ` [PATCH v3 8/8] [HACK] arm64: dts: renesas: draak: Enable LVDS dual-link operation Fabrizio Castro
2019-08-29 15:26 ` [PATCH v3 0/8] Add dual-LVDS panel support to EK874 Rob Herring
2019-09-02 10:01 ` Fabrizio Castro [this message]
2019-10-22 16:30 ` Fabrizio Castro
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