Date:   Wed, 14 Nov 2018 14:58:11 +0800
From:   Chen-Yu Tsai <wens@...e.org>
To:     Jagan Teki <jagan@...rulasolutions.com>
Cc:     André Przywara <andre.przywara@....com>,
        Maxime Ripard <maxime.ripard@...tlin.com>,
        Icenowy Zheng <icenowy@...c.io>,
        Jernej Skrabec <jernej.skrabec@...l.net>,
        Vasily Khoruzhick <anarsoul@...il.com>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will.deacon@....com>,
        David Airlie <airlied@...ux.ie>,
        dri-devel <dri-devel@...ts.freedesktop.org>,
        Mike Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>,
        linux-clk <linux-clk@...r.kernel.org>,
        Michael Trimarchi <michael@...rulasolutions.com>,
        linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
        devicetree <devicetree@...r.kernel.org>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        linux-sunxi@...glegroups.com, linux-amarula@...rulasolutions.com
Subject: Re: [PATCH v4 25/26] [DO NOT MERGE] arm64: dts: allwinner:
 bananapi-m64: Bananapi S070WV20-CT16 DSI panel

On Wed, Nov 14, 2018 at 2:31 PM Jagan Teki <jagan@...rulasolutions.com> wrote:
>
> On Tue, Nov 13, 2018 at 5:52 PM Andre Przywara <andre.przywara@....com> wrote:
> >
> > On Tue, 13 Nov 2018 16:46:32 +0530
> > Jagan Teki <jagan@...rulasolutions.com> wrote:
> >
> > Hi,
> >
> > > This patch add support for Bananapi S070WV20-CT16 DSI panel to
> > > BPI-M64 board.
> > >
> > > DSI panel connected via board DSI port with,
> > > - DC1SW as AVDD supply
> >
> > Are you sure of that? I don't see anything in the schematic to support
> > this. The only power lines that go to the DSI connector are DCDC1 and
> > PS. DC1SW is only connected to PortD on the SoC and to the Ethernet PHY.
> > Is there anything I miss?
>
> Thanks for the comment, yes dc1sw is connected in ephy. I have reused
> dc1, BSP is attached lcd_power1 to axp81x_dc1sw [1]. I just looking
> for someone to comment, may be we can skip this regulator attachment.

That seems sketchy. The schematics show the connector has feeds from both
the unregulated output IPSOUT (PS) and DCDC1. For designs with RGB LCD
panels, we only see the PS feed. Since the LCD panel can be used in either
RGB or MIPI DSI mode, I highly suspect the DCDC1 supply feeds the bridge
IC.

As for DC1SW, this is likely referenced because it provides power to the
GPIO lines that are used to control the LCD panel. If you don't provide
power, you can't pull them up.

While many of us dislike FEX and the new FEX-derived device tree, they
do provide some information, such as regulator usage. Note that each
regulator output has multiple names, which likely denote specific
usages.

I've asked BPI for schematics on the bridge board. Hopefully we'll
have something in more detail. In the meantime, I suggest leaving
this panel out of your next submission, and focus on getting the bulk
of the dsi driver and dts changes in first.

ChenYu

>
> >
> > > - DCDC1 as DVDD supply
> >
> > That seems right, but doesn't match with what you write below.
>
> Commit need to fix s/DCDC1/DLDO1
>
> >
> > > - PD6 gpio for reset pin
> > > - PD5 gpio for backlight enable pin
> > > - PD7 gpio for backlight vdd supply
> > >
> > > Signed-off-by: Jagan Teki <jagan@...rulasolutions.com>
> > > ---
> > >  .../dts/allwinner/sun50i-a64-bananapi-m64.dts | 42
> > > +++++++++++++++++++ 1 file changed, 42 insertions(+)
> > >
> > > diff --git
> > > a/arch/arm64/boot/dts/allwinner/sun50i-a64-bananapi-m64.dts
> > > b/arch/arm64/boot/dts/allwinner/sun50i-a64-bananapi-m64.dts index
> > > ef1c90401bb2..6cb010e3bbd9 100644 ---
> > > a/arch/arm64/boot/dts/allwinner/sun50i-a64-bananapi-m64.dts +++
> > > b/arch/arm64/boot/dts/allwinner/sun50i-a64-bananapi-m64.dts @@ -45,6
> > > +45,7 @@ #include "sun50i-a64.dtsi"
> > >  #include <dt-bindings/gpio/gpio.h>
> > > +#include <dt-bindings/pwm/pwm.h>
> > >
> > >  / {
> > >       model = "BananaPi-M64";
> > > @@ -56,6 +57,15 @@
> > >               serial1 = &uart1;
> > >       };
> > >
> > > +     backlight: backlight {
> > > +             compatible = "pwm-backlight";
> > > +             pwms = <&r_pwm 0 50000 PWM_POLARITY_INVERTED>;
> > > +             brightness-levels = <1 2 4 8 16 32 64 128 512>;
> > > +             default-brightness-level = <2>;
> > > +             enable-gpios = <&pio 3 5 GPIO_ACTIVE_HIGH>; /*
> > > LCD-BL-EN: PD5 */
> > > +             power-supply = <&reg_vdd_backlight>;
> > > +     };
> > > +
> > >       chosen {
> > >               stdout-path = "serial0:115200n8";
> > >       };
> > > @@ -91,6 +101,15 @@
> > >               };
> > >       };
> > >
> > > +     reg_vdd_backlight: vdd-backlight {
> > > +             compatible = "regulator-fixed";
> > > +             regulator-name = "vdd-backlight";
> > > +             regulator-min-microvolt = <3300000>;
> > > +             regulator-max-microvolt = <3300000>;
> > > +             gpio = <&pio 3 7 GPIO_ACTIVE_HIGH>; /* LCD-PWR-EN:
> > > PD7 */
> > > +             enable-active-high;
> > > +     };
> > > +
> > >       wifi_pwrseq: wifi_pwrseq {
> > >               compatible = "mmc-pwrseq-simple";
> > >               reset-gpios = <&r_pio 0 2 GPIO_ACTIVE_LOW>; /* PL2 */
> > > @@ -101,6 +120,23 @@
> > >       status = "okay";
> > >  };
> > >
> > > +&dphy {
> > > +     status = "okay";
> > > +};
> > > +
> > > +&dsi {
> > > +     status = "okay";
> > > +
> > > +     panel@0 {
> > > +             compatible = "bananapi,s070wv20-ct16-icn6211";
> > > +             reg = <0>;
> > > +             avdd-supply = <&reg_dc1sw>;
> >
> > As mentioned above, I don't see this on the DSI connector.
> >
> > > +             dvdd-supply = <&reg_dldo1>;
> >
> > Mmh, this line is connected to the *SoC*, to drive the DSI data lines
> > or the DPHY, presumably. So I wouldn't expect it in the panel node, but
> > rather in the DPHY or DSI node. Although I can't find a power-supply
> > property in those bindings.
>
> Got it, this has to attach via vcc-dsi-supply.
>
> [1] https://github.com/BPI-SINOVOIP/BPI-M64-bsp/blob/master/bootloader/blobs/bpi-m64-lcd7.dts#L2266

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