[PATCH 2/2] arm64: dts: freescale: Add LVDS overlay for TQMa8MPxL
Alexander Stein
alexander.stein at ew.tq-group.com
Mon Jan 2 01:07:26 PST 2023
Hello Richard,
Am Dienstag, 20. Dezember 2022, 09:48:45 CET schrieb Richard Leitner:
> Hi Alexander,
>
> thanks for the series.
>
> On Thu, Dec 08, 2022 at 10:08:42AM +0100, Alexander Stein wrote:
> > This adds an overlay for the supported LVDS display tianma tm070jvhg33.
> > The display timings have to be specified explicitly. Using the typical
> > pixel clock, the LDB clock can not be configured as the 7-fold of that.
> > By setting pixel clock to 74.25 MHz, LDB can be configured to exactly
> > 519.75 MHz.
> >
> > Signed-off-by: Alexander Stein <alexander.stein at ew.tq-group.com>
> > ---
> > To be hold I'm unsure where to list the overlays. I checked other overlays
> > and opted to added them at the end of imx8mp section.
> >
> > arch/arm64/boot/dts/freescale/Makefile | 4 ++
> > .../imx8mp-tqma8mpql-mba8mpxl-lvds.dtso | 61 +++++++++++++++++++
> > 2 files changed, 65 insertions(+)
> > create mode 100644
> > arch/arm64/boot/dts/freescale/imx8mp-tqma8mpql-mba8mpxl-lvds.dtso
> ...
>
> > diff --git
> > a/arch/arm64/boot/dts/freescale/imx8mp-tqma8mpql-mba8mpxl-lvds.dtso
> > b/arch/arm64/boot/dts/freescale/imx8mp-tqma8mpql-mba8mpxl-lvds.dtso new
> > file mode 100644
> > index 0000000000000..ea44d605342ba
> > --- /dev/null
> > +++ b/arch/arm64/boot/dts/freescale/imx8mp-tqma8mpql-mba8mpxl-lvds.dtso
> > @@ -0,0 +1,61 @@
> > +// SPDX-License-Identifier: (GPL-2.0-or-later OR MIT)
> > +/*
> > + * Copyright (c) 2022 TQ-Systems GmbH <linux at ew.tq-group.com>,
> > + * D-82229 Seefeld, Germany.
> > + * Author: Alexander Stein
> > + */
> > +
> > +/dts-v1/;
> > +/plugin/;
> > +
> > +&{/} {
> > + compatible = "tq,imx8mp-tqma8mpql-mba8mpxl", "tq,imx8mp-tqma8mpql",
> > "fsl,imx8mp"; +};
> > +
> > +&backlight_lvds {
> > + status = "okay";
> > +};
> > +
> > +&display {
> > + compatible = "tianma,tm070jvhg33";
> > + status = "okay";
> > +
> > + panel-timing {
> > + clock-frequency = <74250000>;
> > + hactive = <1280>;
> > + vactive = <800>;
> > + hfront-porch = <64>;
> > + hback-porch = <5>;
> > + hsync-len = <1>;
> > + vfront-porch = <40>;
> > + vback-porch = <2>;
> > + vsync-len = <1>;
> > + de-active = <1>;
> > + };
> > +
> > + port {
> > + panel_in_lvds0: endpoint {
> > + remote-endpoint = <&ldb_lvds_ch0>;
> > + };
> > + };
> > +};
> > +
> > +&lcdif2 {
> > + status = "okay";
> > +};
> > +
> > +&lvds_bridge {
> > + status = "okay";
> > +
> > + ports {
> > + port at 1 {
> > + ldb_lvds_ch0: endpoint {
> > + remote-endpoint = <&panel_in_lvds0>;
> > + };
> > + };
> > + };
> > +};
>
> Wouldn't it be possible and easier to read if this was &ldb_lvds_ch0
> only instead of the "whole" &lvds_bridge?
>
> &ldb_lvds_ch0 {
> remote-endpoint = <&panel_in_lvds0>;
> };
Yes it is possible and easier to read. Unfortunately dtbs_check will raise the
follwing warnings when doing so:
> arch/arm64/boot/dts/freescale/imx8mp-tqma8mpql-mba8mpxl-lvds.dtbo: Warning
(graph_port): /fragment at 4: graph port node name should be 'port'
> ../arch/arm64/boot/dts/freescale/imx8mp-tqma8mpql-mba8mpxl-lvds.dtso:
47.15-49.3: Warning (graph_endpoint): /fragment at 4/__overlay__: graph endpoint
node name should be 'endpoint'
> ../arch/arm64/boot/dts/freescale/imx8mp-tqma8mpql-mba8mpxl-lvds.dtso:
47.15-49.3: Warning (graph_endpoint): /fragment at 4/__overlay__: graph
connection to node '/fragment at 2/__overlay__/port/endpoint' is not
bidirectional
I'm not sure which way is the preferred/correct one or if this is just an
issue in dtc, raising the warnings.
Best regards,
Alexander
> > +
> > +&pwm2 {
> > + status = "okay";
> > +};
>
> regards;rl
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