Re: [PATCH 1/2] arm64: dts: exynos: Link DSI panel at port@1 for TM2 board

[Jagan Teki <jagan@amarulasolutions.com>]

Hi Andrzej,

On Tue, Jan 11, 2022 at 2:05 PM Andrzej Hajda <andrzej.hajda@intel.com> wrote:
>
> +CC: dri-devel
>
> On 10.01.2022 16:27, Jagan Teki wrote:
> > TM2 board DSI pipeline has input from MIC and output to
> > s6e3ha2 panel.
> >
> > The existing pipeline has child nodes of ports, panel and
> > MIC is remote-endpoint reference of port@0 of ports.
> >
> > Adding panel as another child node to DSI is unconventional
> > as pipeline has ports child. However it can be true if MIC
> > is added inside port node like this.
> >
> > dsi {
> >       compatible = "samsung,exynos5433-mipi-dsi";
> >       #address-cells = <1>;
> >       #size-cells = <0>;
> >
> >       port {
> >               dsi_to_mic: endpoint {
> >                       remote-endpoint = <&mic_to_dsi>;
> >               };
> >       };
> >
> >       panel@0 {
> >               compatible = "samsung,s6e3hf2";
> >                  reg = <0>;
> >                  vdd3-supply = <&ldo27_reg>;
> >                  vci-supply = <&ldo28_reg>;
> >                  reset-gpios = <&gpg0 0 GPIO_ACTIVE_LOW>;
> >                  enable-gpios = <&gpf1 5 GPIO_ACTIVE_HIGH>;
> >       };
> > };
> >
> > The above pipeline is proper but it requires the DSI input MIC
> > pipeline to update.
> >
> > This patch is trying to add panel at port@1 so-that the entire
> > pipeline before to panel output is untouched.
> >
> > Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
> > Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
> > ---
> >   arch/arm64/boot/dts/exynos/exynos5433-tm2.dts | 16 ++++++++++++++++
> >   1 file changed, 16 insertions(+)
> >
> > diff --git a/arch/arm64/boot/dts/exynos/exynos5433-tm2.dts b/arch/arm64/boot/dts/exynos/exynos5433-tm2.dts
> > index aca01709fd29..e13210c8d7e0 100644
> > --- a/arch/arm64/boot/dts/exynos/exynos5433-tm2.dts
> > +++ b/arch/arm64/boot/dts/exynos/exynos5433-tm2.dts
> > @@ -53,6 +53,16 @@ &cmu_disp {
> >   };
> >
> >   &dsi {
> > +     ports {
> > +             port@1 {
> > +                     reg = <1>;
> > +
> > +                     dsi_out_panel: endpoint {
> > +                             remote-endpoint = <&dsi_in_panel>;
> > +                     };
> > +             };
> > +     };
> > +
> >       panel@0 {
> >               compatible = "samsung,s6e3ha2";
> >               reg = <0>;
> > @@ -60,6 +70,12 @@ panel@0 {
> >               vci-supply = <&ldo28_reg>;
> >               reset-gpios = <&gpg0 0 GPIO_ACTIVE_LOW>;
> >               enable-gpios = <&gpf1 5 GPIO_ACTIVE_HIGH>;
> > +
> > +             port {
> > +                     dsi_in_panel: endpoint {
> > +                             remote-endpoint = <&dsi_out_panel>;
> > +                     };
> > +             };
>
>
> As I already wrote in Exynos thread, DSI host has already parent-child
> relation with the panel - DSI host knows well who is connected to it.
> Adding another links between them is redundant and has no value added.
>
> I have already answered in Exynos thread[1] how could you deal with the
> issue, you have.
>
> [1]:
> https://lore.kernel.org/dri-devel/e541c52b-9751-933b-5eac-783dd0ed9056@intel.com/

I have commented on this thread for better understanding. Please have
a look and respond.

Thanks,
Jagan.