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References: <20210810041630.3673406-1-art@khadas.com> <7dbba936-e8ab-4d47-1af8-0d3d1adb8c30@baylibre.com>
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From:   Art Nikpal <email2tema@gmail.com>
Date:   Wed, 11 Aug 2021 07:21:08 +0800
Message-ID: <CAKaHn9LWCHpAiO8siGmcOxA-FyurwE6x0T5_D7hwpVH72wScNw@mail.gmail.com>
Subject: Re: [PATCH 1/2] arm64: dts: meson: add spdif out to khadas-vim
To:     Neil Armstrong <narmstrong@baylibre.com>
Cc:     Jerome Brunet <jbrunet@baylibre.com>,
        linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
        "open list:ARM/Amlogic Meson..." <linux-amlogic@lists.infradead.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Christian Hewitt <christianshewitt@gmail.com>,
        Artem Lapkin <art@khadas.com>, Nick Xie <nick@khadas.com>,
        Gouwa Wang <gouwa@khadas.com>
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> AFAIK the board doesn't have a physical SPDIF output, but one of the 40pin header can output SPDIF, right ?
Yes it's right

>In this case, following the other boards mainline definitions, we do not enable any function by default
For pins on the 40pin (or other programmable) headers.

ok ! now  i'm understand reason

But maybe it is possible to add this area as commented /* */
and users will have possibilities to uncomment  it.

> DT overlays
Yes but I still don't understand how-to apply dt overlays for EFI+grub
may be somebody can clarify this problem?

On Tue, Aug 10, 2021 at 3:55 PM Neil Armstrong <narmstrong@baylibre.com> wrote:
>
> Hi,
>
> On 10/08/2021 06:16, Artem Lapkin wrote:
> > Add spdif output audio support to khadas-vim
> >
> > Signed-off-by: Artem Lapkin <art@khadas.com>
> > ---
> >  .../dts/amlogic/meson-gxl-s905x-khadas-vim.dts  | 17 +++++++++++++++++
> >  1 file changed, 17 insertions(+)
> >
> > diff --git a/arch/arm64/boot/dts/amlogic/meson-gxl-s905x-khadas-vim.dts b/arch/arm64/boot/dts/amlogic/meson-gxl-s905x-khadas-vim.dts
> > index 60feac0179c0..01f13822a616 100644
> > --- a/arch/arm64/boot/dts/amlogic/meson-gxl-s905x-khadas-vim.dts
> > +++ b/arch/arm64/boot/dts/amlogic/meson-gxl-s905x-khadas-vim.dts
> > @@ -64,6 +64,13 @@ hdmi_connector_in: endpoint {
> >               };
> >       };
> >
> > +     spdif_dit: audio-codec-0 {
> > +             #sound-dai-cells = <0>;
> > +             compatible = "linux,spdif-dit";
> > +             status = "okay";
> > +             sound-name-prefix = "DIT";
> > +     };
> > +
> >       sound {
> >               compatible = "amlogic,gx-sound-card";
> >               model = "KHADAS-VIM";
> > @@ -97,11 +104,21 @@ codec-0 {
> >                               sound-dai = <&hdmi_tx>;
> >                       };
> >               };
> > +
> > +             dai-link-3 {
> > +                     sound-dai = <&aiu AIU_CPU CPU_SPDIF_ENCODER>;
> > +
> > +                     codec-0 {
> > +                             sound-dai = <&spdif_dit>;
> > +                     };
> > +             };
> >       };
> >  };
> >
> >  &aiu {
> >       status = "okay";
> > +     pinctrl-0 = <&spdif_out_h_pins>;
> > +     pinctrl-names = "default";
> >  };
> >
> >  &cec_AO {
> >
>
> AFAIK the board doesn't have a physical SPDIF output, but one of the 40pin header can output SPDIF, right ?
>
> In this case, following the other boards mainline definitions, we do not enable any function by default
> for pins on the 40pin (or other programmable) headers.
>
> There is still ongoing discussions on how to handle that on a more generic level, but you should write a bunch
> of DT overlays for the VIM boards to enable optional functions like SPDIF and store then in a public git
> tree for everybody to use (like armbian or LibreELEC for example) from the U-Boot stage.
>
> Neil