RE: [PATCH 8/8] arm64: dts: renesas: hihope-rzg2-ex: Add LVDS panel support

From: Biju Das <biju.das@bp.renesas.com>
To: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Rob Herring <robh+dt@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Simon Horman <horms@verge.net.au>,
	Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>,
	Geert Uytterhoeven <geert+renesas@glider.be>,
	Magnus Damm <magnus.damm@gmail.com>,
	"linux-renesas-soc@vger.kernel.org" 
	<linux-renesas-soc@vger.kernel.org>,
	"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
	Chris Paterson <Chris.Paterson2@renesas.com>,
	Fabrizio Castro <fabrizio.castro@bp.renesas.com>
Subject: RE: [PATCH 8/8] arm64: dts: renesas: hihope-rzg2-ex: Add LVDS panel support
Date: Wed, 2 Oct 2019 08:30:28 +0000	[thread overview]
Message-ID: <OSBPR01MB2103388A838F8FFC47358BA4B89C0@OSBPR01MB2103.jpnprd01.prod.outlook.com> (raw)
In-Reply-To: <20191001182510.GJ4735@pendragon.ideasonboard.com>

Hi Laurent,

Thanks for your feedback.

> Subject: Re: [PATCH 8/8] arm64: dts: renesas: hihope-rzg2-ex: Add LVDS
> panel support
> 
> Hi Biju,
> 
> Thank you for the patch.
> 
> On Tue, Oct 01, 2019 at 01:15:24PM +0100, Biju Das wrote:
> > This patch adds support for Advantech idk-1110wr LVDS panel.
> > The HiHope RZ/G2[MN] is advertised as compatible with panel idk-1110wr
> > from Advantech, however the panel isn't sold alongside the board.
> >
> > Signed-off-by: Biju Das <biju.das@bp.renesas.com>
> > ---
> >  arch/arm64/boot/dts/renesas/hihope-rzg2-ex.dtsi  | 30
> > +++++++++++++++++++  arch/arm64/boot/dts/renesas/rzg2-panel-
> lvds.dtsi
> > | 37 ++++++++++++++++++++++++
> >  2 files changed, 67 insertions(+)
> >  create mode 100644 arch/arm64/boot/dts/renesas/rzg2-panel-lvds.dtsi
> >
> > diff --git a/arch/arm64/boot/dts/renesas/hihope-rzg2-ex.dtsi
> > b/arch/arm64/boot/dts/renesas/hihope-rzg2-ex.dtsi
> > index 70f9a2a..ae1ef2d 100644
> > --- a/arch/arm64/boot/dts/renesas/hihope-rzg2-ex.dtsi
> > +++ b/arch/arm64/boot/dts/renesas/hihope-rzg2-ex.dtsi
> > @@ -5,6 +5,8 @@
> >   * Copyright (C) 2019 Renesas Electronics Corp.
> >   */
> >
> > +#include "rzg2-panel-lvds.dtsi"
> > +
> >  / {
> >  	aliases {
> >  		ethernet0 = &avb;
> > @@ -51,6 +53,34 @@
> >  	status = "okay";
> >  };
> >
> > +&gpio1 {
> > +	/*
> > +	 * When GP1_20 is LOW LVDS0 is connected to the LVDS connector
> > +	 * When GP1_20 is HIGH LVDS0 is connected to the LT8918L
> > +	 */
> > +	lvds-connector-en-gpio {
> > +		gpio-hog;
> > +		gpios = <20 GPIO_ACTIVE_HIGH>;
> > +		output-low;
> > +		line-name = "lvds-connector-en-gpio";
> > +	};
> > +};
> > +
> > +&lvds0 {
> > +	/* Uncomment  below line to enable lvds panel connected to
> RZ/G2N board
> > +	 */
> > +
> > +	/* status = "okay"; */
> > +
> > +	ports {
> > +		port@1 {
> > +			lvds_connector: endpoint {
> > +				remote-endpoint =
> <&panel_in_advantech_idk_1110wr>;
> > +			};
> > +		};
> > +	};
> > +};
> > +
> >  &pciec0 {
> >  	status = "okay";
> >  };
> > diff --git a/arch/arm64/boot/dts/renesas/rzg2-panel-lvds.dtsi
> > b/arch/arm64/boot/dts/renesas/rzg2-panel-lvds.dtsi
> > new file mode 100644 advantech,idk-2121wr
> > index 0000000..768a8ec
> > --- /dev/null
> > +++ b/arch/arm64/boot/dts/renesas/rzg2-panel-lvds.dtsi
> 
> Should this be named according to the panel name istead of just "panel-lvds"
> ? It could be used by any board, and this board could also use a different
> LVDS panel.

I thought ,we can use a common file for all the LVDS panels used by RZ/G2 boards and refer the panel from board dtsi.
For eg:- RZ/G2[MN] will refer " panel_in_advantech_idk_1110wr" and RZ/G2E will refer " panel_in_advantech_idk_2121wr"
If user wants a different panel, then  needs to define panel definitions in this file and use it.  But I am not sure it is the right thing to do.

OK. Anyway I will create a panel specific dtsi file and send V2.

> > @@ -0,0 +1,37 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Device Tree Source for the LVDS panels connected to RZ/G2 boards
> > + *
> > + * Copyright (C) 2019 Renesas Electronics Corp.
> > + */
> > +
> > +/ {
> > +
> > +	panel-lvds {
> > +		compatible = "advantech,idk-1110wr", "panel-lvds";
> > +
> > +		width-mm = <223>;
> > +		height-mm = <125>;
> > +
> > +		data-mapping = "jeida-24";
> > +
> > +		panel-timing {
> > +			/* 1024x600 @60Hz */
> > +			clock-frequency = <51200000>;
> > +			hactive = <1024>;
> > +			vactive = <600>;
> > +			hsync-len = <240>;
> > +			hfront-porch = <40>;
> > +			hback-porch = <40>;
> > +			vfront-porch = <15>;
> > +			vback-porch = <10>;
> > +			vsync-len = <10>;
> > +		};
> > +
> > +		port {
> > +			panel_in_advantech_idk_1110wr: endpoint {
> 
> Could we abbreviate the label name to panel_in ? That way the board .dts
> wouldn't need to update the remote-endpoint phandle to use a different
> panel, only the #include would need to be changed.

OK. Will change this.

> > +				remote-endpoint = <&lvds_connector>;
> > +			};
> > +		};
> > +	};
> > +};
> 
> For the same reason I would set the remote-endpoint for &lvds_connector
> here. See arch/arm/boot/dts/r8a77xx-aa104xd12-panel.dtsi for an example.

OK.  Will add this.

Regards,
Biju