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References: <20201218195033.2301127-1-contact@paulk.fr> <3035881.9zrMQt1rZd@jernej-laptop>
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From:   Chen-Yu Tsai <wens@csie.org>
Date:   Wed, 30 Dec 2020 11:29:39 +0800
Message-ID: <CAGb2v64xtm5wBuL6bkAYYFK2irjxs58df_xeHws6vaG_QDux+g@mail.gmail.com>
Subject: Re: [PATCH] ARM: dts: sun8i-v3s: Add CSI0 MCLK pin definition
To:     Jernej Skrabec <jernej.skrabec@siol.net>
Cc:     devicetree <devicetree@vger.kernel.org>,
        linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        Paul Kocialkowski <contact@paulk.fr>,
        Maxime Ripard <mripard@kernel.org>
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Precedence: bulk

On Tue, Dec 22, 2020 at 4:17 PM Jernej Škrabec <jernej.skrabec@siol.net> wrote:
>
> Hi!
>
> Dne petek, 18. december 2020 ob 20:50:33 CET je Paul Kocialkowski napisal(a):
> > This adds a device-tree definition for the CSI0 MCLK pin,
> > which can be used for feeding MIPI CSI-2 sensors.
> >
> > Signed-off-by: Paul Kocialkowski <contact@paulk.fr>
>
> Is this used anywhere? Current policy is to add pin definitions only if any
> user exists.

IIRC we sort of loosened that requirement with the use of /omit-if-no-ref/.
The A20 dtsi file has a whole bunch of pins defined that are not directly
used but are available for users to reference, especially in overlays.
The "-@" parameter for the device tree compiler, used to build overlay
compatible DTBs, makes the compiler ignore /omit-if-no-ref/ and include
all the nodes.

ChenYu

> Best regards,
> Jernej
>
> > ---
> >  arch/arm/boot/dts/sun8i-v3s.dtsi | 6 ++++++
> >  1 file changed, 6 insertions(+)
> >
> > diff --git a/arch/arm/boot/dts/sun8i-v3s.dtsi
> > b/arch/arm/boot/dts/sun8i-v3s.dtsi index a9f5795d4e57..bff822b9fa01 100644
> > --- a/arch/arm/boot/dts/sun8i-v3s.dtsi
> > +++ b/arch/arm/boot/dts/sun8i-v3s.dtsi
> > @@ -337,6 +337,12 @@ pio: pinctrl@1c20800 {
> >                       interrupt-controller;
> >                       #interrupt-cells = <3>;
> >
> > +                     /omit-if-no-ref/
> > +                     csi0_mclk_pin: csi0-mclk-pin {
> > +                             pins = "PE20";
> > +                             function = "csi_mipi";
> > +                     };
> > +
> >                       /omit-if-no-ref/
> >                       csi1_8bit_pins: csi1-8bit-pins {
> >                               pins = "PE0", "PE2", "PE3",
> "PE8", "PE9",
>
>
>
>