Re: [PATCH 7/7] ARM: dts: r8a7742-iwg21d-q7: Add LCD support

From: "Lad, Prabhakar" <prabhakar.csengg@gmail.com>
To: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>,
	Geert Uytterhoeven <geert+renesas@glider.be>,
	Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>,
	David Airlie <airlied@linux.ie>, Rob Herring <robh+dt@kernel.org>,
	Magnus Damm <magnus.damm@gmail.com>,
	Daniel Vetter <daniel@ffwll.ch>,
	DRI Development <dri-devel@lists.freedesktop.org>,
	Linux-Renesas <linux-renesas-soc@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
	<devicetree@vger.kernel.org>
Subject: Re: [PATCH 7/7] ARM: dts: r8a7742-iwg21d-q7: Add LCD support
Date: Thu, 13 Aug 2020 13:54:35 +0100	[thread overview]
Message-ID: <CA+V-a8sVA9r3_yrM6z7EX-XGp1d6Wy-6LjWsO7Td93C-236jvg@mail.gmail.com> (raw)
In-Reply-To: <20200811112638.GF6054@pendragon.ideasonboard.com>

Hi Laurent,

Thank you for the review.

On Tue, Aug 11, 2020 at 12:26 PM Laurent Pinchart
<laurent.pinchart@ideasonboard.com> wrote:
>
> Hi Prabhakar,
>
> Thank you for the patch.
>
> On Fri, Aug 07, 2020 at 06:49:54PM +0100, Lad Prabhakar wrote:
> > The iwg21d comes with a 7" capacitive touch screen, therefore
> > add support for it.
> >
> > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> > Reviewed-by: Marian-Cristian Rotariu <marian-cristian.rotariu.rb@bp.renesas.com>
> > ---
> >  arch/arm/boot/dts/r8a7742-iwg21d-q7.dts | 84 +++++++++++++++++++++++++
> >  1 file changed, 84 insertions(+)
> >
> > diff --git a/arch/arm/boot/dts/r8a7742-iwg21d-q7.dts b/arch/arm/boot/dts/r8a7742-iwg21d-q7.dts
> > index b3461a61a4bf..cf59fd61e422 100644
> > --- a/arch/arm/boot/dts/r8a7742-iwg21d-q7.dts
> > +++ b/arch/arm/boot/dts/r8a7742-iwg21d-q7.dts
> > @@ -30,6 +30,7 @@
> >
> >  /dts-v1/;
> >  #include "r8a7742-iwg21m.dtsi"
> > +#include <dt-bindings/pwm/pwm.h>
> >
> >  / {
> >       model = "iWave Systems RainboW-G21D-Qseven board based on RZ/G1H";
> > @@ -52,6 +53,50 @@
> >               clock-frequency = <26000000>;
> >       };
> >
> > +     lcd_backlight: backlight {
> > +             compatible = "pwm-backlight";
> > +             pwms = <&tpu 2 5000000 0>;
> > +             brightness-levels = <0 4 8 16 32 64 128 255>;
> > +             pinctrl-0 = <&backlight_pins>;
> > +             pinctrl-names = "default";
> > +             default-brightness-level = <7>;
> > +             enable-gpios = <&gpio3 11 GPIO_ACTIVE_HIGH>;
>
> It's actually a power supply, not an enable GPIO, but it doesn't matter
> much, I don't think there's a need to declare a regulator just for the
> sake of it.
>
Agreed will leave it as is.

> > +     };
> > +
> > +     lvds-receiver {
> > +             compatible = "ti,ds90cf384a", "lvds-decoder";
> > +             powerdown-gpios = <&gpio5 28 GPIO_ACTIVE_LOW>;
>
> This should be handled as a shared power supply, as it's also needed for
> the touch screen. Biju has sent patches for the iwg20d that fixes a
> probe issue due to that problem, I think you can just copy the fix.
>
Done.

> > +
> > +             ports {
> > +                     #address-cells = <1>;
> > +                     #size-cells = <0>;
> > +
> > +                     port@0 {
> > +                             reg = <0>;
> > +                             lvds_receiver_in: endpoint {
> > +                                     remote-endpoint = <&lvds0_out>;
> > +                             };
> > +                     };
> > +                     port@1 {
> > +                             reg = <1>;
> > +                             lvds_receiver_out: endpoint {
> > +                                     remote-endpoint = <&panel_in>;
> > +                             };
> > +                     };
> > +             };
> > +     };
> > +
> > +     panel {
> > +             compatible = "edt,etm0700g0dh6";
> > +             backlight = <&lcd_backlight>;
> > +
> > +             port {
> > +                     panel_in: endpoint {
> > +                             remote-endpoint = <&lvds_receiver_out>;
> > +                     };
> > +             };
> > +     };
> > +
> >       reg_1p5v: 1p5v {
> >               compatible = "regulator-fixed";
> >               regulator-name = "1P5V";
> > @@ -129,12 +174,31 @@
> >               VDDIO-supply = <&reg_3p3v>;
> >               VDDD-supply = <&reg_1p5v>;
> >       };
> > +
> > +     touch: touchpanel@38 {
> > +             compatible = "edt,edt-ft5406";
> > +             reg = <0x38>;
> > +             interrupt-parent = <&gpio0>;
> > +             interrupts = <24 IRQ_TYPE_EDGE_FALLING>;
>
> Should the reset GPIO also be wired ? It seems to be shared with the
> audio codec though, which is annoying.
>
Done.

> > +     };
> >  };
> >
> >  &cmt0 {
> >       status = "okay";
> >  };
> >
> > +&du {
> > +     status = "okay";
> > +};
> > +
> > +&gpio0 {
> > +     touch-interrupt {
> > +             gpio-hog;
> > +             gpios = <24 GPIO_ACTIVE_LOW>;
> > +             input;
> > +     };
>
> Is this needed, or does requesting the interrupt in the touch screen
> driver configured the GPIO to an input automatically ?
>
Yes this is needed, the touch driver does not configure the pin as
GPIO input without this touch doesn't work.

Cheers,
Prabhakar