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Date:   Tue, 8 Dec 2020 09:03:34 +0100
From:   Krzysztof Kozlowski <krzk@kernel.org>
To:     "S.j. Wang" <shengjiu.wang@nxp.com>
Cc:     "robh+dt@kernel.org" <robh+dt@kernel.org>,
        "shawnguo@kernel.org" <shawnguo@kernel.org>,
        "s.hauer@pengutronix.de" <s.hauer@pengutronix.de>,
        "kernel@pengutronix.de" <kernel@pengutronix.de>,
        "festevam@gmail.com" <festevam@gmail.com>,
        dl-linux-imx <linux-imx@nxp.com>,
        "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
        "linux-arm-kernel@lists.infradead.org" 
        <linux-arm-kernel@lists.infradead.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] arm64: dts: imx8mn: Fix duplicate node name
Message-ID: <20201208080334.GA4026@kozik-lap>
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On Tue, Dec 08, 2020 at 03:16:35AM +0000, S.j. Wang wrote:
> Hi
> 
> > 
> > On Mon, Dec 07, 2020 at 02:21:40PM +0100, Krzysztof Kozlowski wrote:
> > > On Mon, Dec 07, 2020 at 02:53:24PM +0800, Shengjiu Wang wrote:
> > > > Error log:
> > > > sysfs: cannot create duplicate filename
> > '/bus/platform/devices/30000000.bus'
> > > >
> > > > The spba bus name is duplicate with aips bus name.
> > > > Refine spba bus name to fix this issue.
> > > >
> > > > Fixes: 970406eaef3a ("arm64: dts: imx8mn: Enable Asynchronous Sample
> > > > Rate Converter")
> > > > Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
> > > > ---
> > > >  arch/arm64/boot/dts/freescale/imx8mn.dtsi | 2 +-
> > > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > >
> > > > diff --git a/arch/arm64/boot/dts/freescale/imx8mn.dtsi
> > > > b/arch/arm64/boot/dts/freescale/imx8mn.dtsi
> > > > index fd669c0f3fe5..30762eb4f0a7 100644
> > > > --- a/arch/arm64/boot/dts/freescale/imx8mn.dtsi
> > > > +++ b/arch/arm64/boot/dts/freescale/imx8mn.dtsi
> > > > @@ -246,7 +246,7 @@ aips1: bus@30000000 {
> > > >                     #size-cells = <1>;
> > > >                     ranges;
> > > >
> > > > -                   spba: bus@30000000 {
> > > > +                   spba: spba-bus@30000000 {
> > >
> > > The proper node name is "bus" so basically you introduce wrong name to
> > > other problem.  Introducing wrong names at least requires a comment.
> > 
> > I just noticed that my message was barely understandable... so let me fix it:
> > 
> > The proper node name is "bus" so basically you introduce wrong name to
> > _fix_ other problem.  Introducing wrong names at least requires a comment.
> > 
> > > However the actual problem here is not in node names but in addresses:
> > >
> > >       aips1: bus@30000000 {
> > >               spba: bus@30000000 {
> > >
> > > You have to devices with the same unit address. How do you share the
> > > address space?
> > >
> > > I think this should be rather fixed.
> > 
> > And again, hungry keyboard ate a letter, so:
> > 
> > You have _two_ devices with the same unit address. How do you share the
> > address space?
> > I think this should be rather fixed.
> > 
> 
> spba is the first block of aips1 space, so it has same start address as
> aips1.

The reference manual describes it "Reserved for SDMA2 internal memory",
so indeed it is first address but does it have to be mapped?
Anyway, why don't you use ranges to remove the conflict?

Best regards,
Krzysztof