Message-ID: <20191024182749.czihj3gnvj5yz2eo@hendrix>
Date:   Thu, 24 Oct 2019 20:27:49 +0200
From:   Maxime Ripard <mripard@...nel.org>
To:     Jagan Teki <jagan@...rulasolutions.com>
Cc:     Chen-Yu Tsai <wens@...e.org>, David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Michael Trimarchi <michael@...rulasolutions.com>,
        Icenowy Zheng <icenowy@...c.io>,
        linux-sunxi <linux-sunxi@...glegroups.com>,
        dri-devel <dri-devel@...ts.freedesktop.org>,
        linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        devicetree <devicetree@...r.kernel.org>
Subject: Re: [PATCH v10 5/6] arm64: dts: allwinner: a64: Add MIPI DSI pipeline

On Thu, Oct 24, 2019 at 01:28:28PM +0530, Jagan Teki wrote:
> On Thu, Oct 17, 2019 at 3:22 PM Maxime Ripard <mripard@...nel.org> wrote:
> >
> > On Wed, Oct 16, 2019 at 02:19:44PM +0530, Jagan Teki wrote:
> > > On Wed, Oct 16, 2019 at 1:33 PM Maxime Ripard <mripard@...nel.org> wrote:
> > > >
> > > > On Mon, Oct 14, 2019 at 05:37:50PM +0530, Jagan Teki wrote:
> > > > > On Mon, Oct 7, 2019 at 4:27 PM Maxime Ripard <mripard@...nel.org> wrote:
> > > > > >
> > > > > > On Sat, Oct 05, 2019 at 07:49:12PM +0530, Jagan Teki wrote:
> > > > > > > Add MIPI DSI pipeline for Allwinner A64.
> > > > > > >
> > > > > > > - dsi node, with A64 compatible since it doesn't support
> > > > > > >   DSI_SCLK gating unlike A33
> > > > > > > - dphy node, with A64 compatible with A33 fallback since
> > > > > > >   DPHY on A64 and A33 is similar
> > > > > > > - finally, attach the dsi_in to tcon0 for complete MIPI DSI
> > > > > > >
> > > > > > > Signed-off-by: Jagan Teki <jagan@...rulasolutions.com>
> > > > > > > Tested-by: Merlijn Wajer <merlijn@...zup.org>
> > > > > > > ---
> > > > > > >  arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi | 38 +++++++++++++++++++
> > > > > > >  1 file changed, 38 insertions(+)
> > > > > > >
> > > > > > > diff --git a/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi b/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi
> > > > > > > index 69128a6dfc46..ad4170b8aee0 100644
> > > > > > > --- a/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi
> > > > > > > +++ b/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi
> > > > > > > @@ -382,6 +382,12 @@
> > > > > > >                                       #address-cells = <1>;
> > > > > > >                                       #size-cells = <0>;
> > > > > > >                                       reg = <1>;
> > > > > > > +
> > > > > > > +                                     tcon0_out_dsi: endpoint@1 {
> > > > > > > +                                             reg = <1>;
> > > > > > > +                                             remote-endpoint = <&dsi_in_tcon0>;
> > > > > > > +                                             allwinner,tcon-channel = <1>;
> > > > > > > +                                     };
> > > > > > >                               };
> > > > > > >                       };
> > > > > > >               };
> > > > > > > @@ -1003,6 +1009,38 @@
> > > > > > >                       status = "disabled";
> > > > > > >               };
> > > > > > >
> > > > > > > +             dsi: dsi@...0000 {
> > > > > > > +                     compatible = "allwinner,sun50i-a64-mipi-dsi";
> > > > > > > +                     reg = <0x01ca0000 0x1000>;
> > > > > > > +                     interrupts = <GIC_SPI 89 IRQ_TYPE_LEVEL_HIGH>;
> > > > > > > +                     clocks = <&ccu CLK_BUS_MIPI_DSI>;
> > > > > > > +                     clock-names = "bus";
> > > > > >
> > > > > > This won't validate with the bindings you have either here, since it
> > > > > > still expects bus and mod.
> > > > > >
> > > > > > I guess in that cas, we can just drop clock-names, which will require
> > > > > > a bit of work on the driver side as well.
> > > > >
> > > > > Okay.
> > > > > mod clock is not required for a64, ie reason we have has_mod_clk quirk
> > > > > patch. Adjust the clock-names: on dt-bindings would make sense here,
> > > > > what do you think?
> > > >
> > > > I'm confused, what are you suggesting?
> > >
> > > Sorry for the confusion.
> > >
> > > The mod clock is not required for A64 and we have a patch for handling
> > > mod clock using has_mod_clk quirk(on the series), indeed the mod clock
> > > is available in A31 and not needed for A64. So, to satisfy this
> > > requirement the clock-names on dt-bindings can update to make mod
> > > clock-name is optional and bus clock is required.
> >
> > No, the bus clock name is not needed if there's only one clock.
>
> Okay, is it because the same clock handle it on PHY side?

No, because there's only one clock and thus you don't need to
differentiate them.

> >
> > > I'm not exactly sure, this is correct but trying to understand if it
> > > is possible or not? something like
> > >
> > >    clocks:
> > >       minItems: 1
> > >       maxItems: 2
> > >      items:
> > >        - description: Bus Clock
> > >        - description: Module Clock
> >
> > That's correct.
> >
> > >    clock-names:
> > >       minItems: 1
> > >       maxItems: 2
> > >      items:
> > >        - const: bus
> > >        - const: mod
> >
> > Here, just keep the current clock-names definition, and make it
> > required only for SoCs that are not the A64
>
> Okay, please have a look here I have pasted the diff for comments.
>
>    clocks:
> +    minItems: 2
>      items:
>        - description: Bus Clock
>        - description: Module Clock

Didn't you tell me that you didn't need the module clock?

How do you handle the case were you just have the bus clock then?

Maxime

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