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From:   Vasily Khoruzhick <anarsoul@gmail.com>
Date:   Wed, 15 May 2019 08:08:57 -0700
Message-ID: <CA+E=qVf6K_0T0x2Hsfp6EDqM-ok6xiAzeZPvp6SRg0yt010pKA@mail.gmail.com>
Subject: Re: [PATCH 4/4] arm64: DTS: allwinner: a64: enable ANX6345 bridge on Teres-I
To:     Torsten Duwe <duwe@lst.de>
Cc:     David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>,
        Rob Herring <robh+dt@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Thierry Reding <thierry.reding@gmail.com>,
        Maxime Ripard <maxime.ripard@bootlin.com>,
        Chen-Yu Tsai <wens@csie.org>,
        Andrzej Hajda <a.hajda@samsung.com>,
        Laurent Pinchart <Laurent.pinchart@ideasonboard.com>,
        Icenowy Zheng <icenowy@aosc.io>,
        Sean Paul <seanpaul@chromium.org>,
        Harald Geyer <harald@ccbib.org>,
        dri-devel <dri-devel@lists.freedesktop.org>,
        devicetree <devicetree@vger.kernel.org>,
        arm-linux <linux-arm-kernel@lists.infradead.org>,
        linux-kernel <linux-kernel@vger.kernel.org>
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On Wed, May 15, 2019 at 12:32 AM Torsten Duwe <duwe@lst.de> wrote:
>
> On Tue, 14 May 2019 10:48:40 -0700
> Vasily Khoruzhick <anarsoul@gmail.com> wrote:
>
> > > +       anx6345: anx6345@38 {
> > > +               compatible = "analogix,anx6345";
> > > +               reg = <0x38>;
> > > +               reset-gpios = <&pio 3 24 GPIO_ACTIVE_LOW>; /* PD24
> > > */
> > > +               dvdd25-supply = <&reg_dldo2>;
> > > +               dvdd12-supply = <&reg_dldo3>;
> > > +
> > > +               port {
> > > +                       anx6345_in: endpoint {
> > > +                               remote-endpoint =
> > > <&tcon0_out_anx6345>;
> > > +                       };
> > > +               };
> >
> > It doesn't comply with bindings document. You need to add out endpoint
>
> It does comply with the bindings. The ports are all optional.
> As far as DT is concerned, the signal path ends here. This is also the
> final component _required_ to get the Linux kernel DRI up and running.

Ugh, then bindings should be fixed. It's not optional. It may work if
bootloader enables power for you, but it won't if you disable display
driver in u-boot.

> > as well, and to do so you need to add bindings for eDP connector first
> > and then implement panel driver.
> > See Rob's suggestions here: http://patchwork.ozlabs.org/patch/1042593/
>
> Well, one *could* extend the hardware description down to the actual
> panel if necessary, but on the Teres-I it is not. I assume the panel
> they ship provides proper EDID to the anx6345, because the display
> works fine here with this DT.

I guess you're testing it with older version of anx6345. Newer version
that supports power management [1] needs startup delay for panel.
Another issue that you're seeing is that backlight is not disabled on
DPMS events. All in all, you need to describe panel in dts.

[1] https://github.com/anarsoul/linux-2.6/commit/2fbf9c242419c8bda698e8331a02d4312143ae2c


> Do I understand this correctly that the (3 different?) pinebook panels
> are not that easy to handle? I try to include the pinebook wherever
> possible, just because it's so similar, but here I'm a bit lost, so I
> had to omit these parts.
>
> Should I also have added a Tested-by: ? ;-)

I don't have Teres, so I haven't tested these.

>
>         Torsten