[2/2] arm64: dts: renesas: rzg2ul-smarc: Add /omit-if-no-ref/ to pinmux

From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

In preparation to re-use the RZ/G2UL SMARC SoM and carrier DTS/I with the
RZ/Five add /omit-if-no-ref/ keyword to pinmux entries as the support for
RZ/Five SMARC EVK will be gradually added.

Once we have full blown support for RZ/Five SMARC EVK we can get rid of
the /omit-if-no-ref/ keyword.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
---
 .../boot/dts/renesas/rzg2ul-smarc-pinfunction.dtsi  | 13 +++++++++++++
 arch/arm64/boot/dts/renesas/rzg2ul-smarc-som.dtsi   |  7 +++++++
 2 files changed, 20 insertions(+)

Hi Geert,

Thank you for the review.

On Tue, Oct 25, 2022 at 9:13 AM Geert Uytterhoeven <geert@linux-m68k.org> wrote:
>
> Hi Prabhakar,
>
> On Thu, Sep 15, 2022 at 6:53 PM Prabhakar <prabhakar.csengg@gmail.com> wrote:
> > From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> >
> > In preparation to re-use the RZ/G2UL SMARC SoM and carrier DTS/I with the
> > RZ/Five add /omit-if-no-ref/ keyword to pinmux entries as the support for
> > RZ/Five SMARC EVK will be gradually added.
> >
> > Once we have full blown support for RZ/Five SMARC EVK we can get rid of
> > the /omit-if-no-ref/ keyword.
> >
> > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
>
> Thanks for your patch!
>
> I finally had a deeper look at this...
>
> Why do you want to disable these nodes? While they are indeed not
> used yet on RZ/Five, they are valid hardware descriptions for the
> RZ/Five SMARC EVK, and their presence doesn't harm anything.
>
> I do see a valid use case for marking pin control subnodes with
> /omit-if-no-ref/: you can provide all possible configurations as a
> convenience for the user, so the user no longer has to look up the
> numeric parameters of the RZG2L_PORT_PINMUX() macros.
> But IMHO those would belong in the SoC-specific .dtsi, not in a
> board .dtsi.  See e.g. the massive use of /omit-if-no-ref/ in sunxi
> and rockchip .dtsi files.
>
> Am I missing something?
>
My intention was to keep the DTB as minimal as possible so that it
includes just the required pinmuxes which were enabled on the RZ/Five.
For example [0], [1] we do delete the pinctrl for the nodes which are
marked as disabled. Do you think we should drop it?

But now that things are falling in place for RZ/Five we can ignore this patch.

[0] arch/arm64/boot/dts/renesas/rzg2lc-smarc.dtsi
[1] arch/arm64/boot/dts/renesas/rzg2ul-smarc.dtsi

Cheers,
Prabhakar

> > --- a/arch/arm64/boot/dts/renesas/rzg2ul-smarc-pinfunction.dtsi
> > +++ b/arch/arm64/boot/dts/renesas/rzg2ul-smarc-pinfunction.dtsi
> > @@ -12,12 +12,14 @@ &pinctrl {
> >         pinctrl-0 = <&sound_clk_pins>;
>                         ^^^^^^^^^^^^^^
> >         pinctrl-names = "default";
> >
> > +       /omit-if-no-ref/
> >         can0_pins: can0 {
> >                 pinmux = <RZG2L_PORT_PINMUX(1, 1, 3)>, /* TX */
> >                          <RZG2L_PORT_PINMUX(1, 2, 3)>; /* RX */
> >         };
> >
> >  #if (SW_ET0_EN_N)
> > +       /omit-if-no-ref/
> >         can0-stb-hog {
> >                 gpio-hog;
> >                 gpios = <RZG2L_GPIO(2, 2) GPIO_ACTIVE_HIGH>;
>
> > @@ -94,11 +103,13 @@ sd1_mux_uhs {
> >                 };
> >         };
> >
> > +       /omit-if-no-ref/
> >         sound_clk_pins: sound_clk {
>
> FTR, this one is always referenced.
>
> >                 pins = "AUDIO_CLK1", "AUDIO_CLK2";
> >                 input-enable;
> >         };
>
> Gr{oetje,eeting}s,
>
>                         Geert
>
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
>
> In personal conversations with technical people, I call myself a hacker. But
> when I'm talking to journalists I just say "programmer" or something like that.
>                                 -- Linus Torvalds

Hi Prabhakar,

On Wed, Oct 26, 2022 at 12:39 AM Lad, Prabhakar
<prabhakar.csengg@gmail.com> wrote:
> On Tue, Oct 25, 2022 at 9:13 AM Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> > On Thu, Sep 15, 2022 at 6:53 PM Prabhakar <prabhakar.csengg@gmail.com> wrote:
> > > From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> > >
> > > In preparation to re-use the RZ/G2UL SMARC SoM and carrier DTS/I with the
> > > RZ/Five add /omit-if-no-ref/ keyword to pinmux entries as the support for
> > > RZ/Five SMARC EVK will be gradually added.
> > >
> > > Once we have full blown support for RZ/Five SMARC EVK we can get rid of
> > > the /omit-if-no-ref/ keyword.
> > >
> > > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> >
> > Thanks for your patch!
> >
> > I finally had a deeper look at this...
> >
> > Why do you want to disable these nodes? While they are indeed not
> > used yet on RZ/Five, they are valid hardware descriptions for the
> > RZ/Five SMARC EVK, and their presence doesn't harm anything.
> >
> > I do see a valid use case for marking pin control subnodes with
> > /omit-if-no-ref/: you can provide all possible configurations as a
> > convenience for the user, so the user no longer has to look up the
> > numeric parameters of the RZG2L_PORT_PINMUX() macros.
> > But IMHO those would belong in the SoC-specific .dtsi, not in a
> > board .dtsi.  See e.g. the massive use of /omit-if-no-ref/ in sunxi
> > and rockchip .dtsi files.
> >
> > Am I missing something?
> >
> My intention was to keep the DTB as minimal as possible so that it
> includes just the required pinmuxes which were enabled on the RZ/Five.
> For example [0], [1] we do delete the pinctrl for the nodes which are
> marked as disabled. Do you think we should drop it?

You mean

    /delete-property/ pinctrl-0;
    /delete-property/ pinctrl-names;

?
These do not delete pinctrl subnodes, but pinctrl properties in disabled
device nodes pointing to pinctrl subnodes.  The actual pinctrl subnodes
are still present.

> But now that things are falling in place for RZ/Five we can ignore this patch.

Agreed.

> [0] arch/arm64/boot/dts/renesas/rzg2lc-smarc.dtsi
> [1] arch/arm64/boot/dts/renesas/rzg2ul-smarc.dtsi

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Hi Geert,

On Wed, Oct 26, 2022 at 8:29 AM Geert Uytterhoeven <geert@linux-m68k.org> wrote:
>
> Hi Prabhakar,
>
> On Wed, Oct 26, 2022 at 12:39 AM Lad, Prabhakar
> <prabhakar.csengg@gmail.com> wrote:
> > On Tue, Oct 25, 2022 at 9:13 AM Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> > > On Thu, Sep 15, 2022 at 6:53 PM Prabhakar <prabhakar.csengg@gmail.com> wrote:
> > > > From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> > > >
> > > > In preparation to re-use the RZ/G2UL SMARC SoM and carrier DTS/I with the
> > > > RZ/Five add /omit-if-no-ref/ keyword to pinmux entries as the support for
> > > > RZ/Five SMARC EVK will be gradually added.
> > > >
> > > > Once we have full blown support for RZ/Five SMARC EVK we can get rid of
> > > > the /omit-if-no-ref/ keyword.
> > > >
> > > > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> > >
> > > Thanks for your patch!
> > >
> > > I finally had a deeper look at this...
> > >
> > > Why do you want to disable these nodes? While they are indeed not
> > > used yet on RZ/Five, they are valid hardware descriptions for the
> > > RZ/Five SMARC EVK, and their presence doesn't harm anything.
> > >
> > > I do see a valid use case for marking pin control subnodes with
> > > /omit-if-no-ref/: you can provide all possible configurations as a
> > > convenience for the user, so the user no longer has to look up the
> > > numeric parameters of the RZG2L_PORT_PINMUX() macros.
> > > But IMHO those would belong in the SoC-specific .dtsi, not in a
> > > board .dtsi.  See e.g. the massive use of /omit-if-no-ref/ in sunxi
> > > and rockchip .dtsi files.
> > >
> > > Am I missing something?
> > >
> > My intention was to keep the DTB as minimal as possible so that it
> > includes just the required pinmuxes which were enabled on the RZ/Five.
> > For example [0], [1] we do delete the pinctrl for the nodes which are
> > marked as disabled. Do you think we should drop it?
>
> You mean
>
>     /delete-property/ pinctrl-0;
>     /delete-property/ pinctrl-names;
>
> ?
> These do not delete pinctrl subnodes, but pinctrl properties in disabled
> device nodes pointing to pinctrl subnodes.  The actual pinctrl subnodes
> are still present.
>
Ahh right the pinctrl subnodes will still remain.

Cheers,
Prabhakar