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From:   "Aakarsh Jain" <aakarsh.jain@samsung.com>
To:     "'Krzysztof Kozlowski'" <krzysztof.kozlowski@linaro.org>,
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Subject: RE: [PATCH 3/3] arm64: dts: exynos: Rename compatible string
 property from version to SOC specific
Date:   Fri, 4 Nov 2022 16:19:24 +0530
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> -----Original Message-----
> From: Krzysztof Kozlowski =5Bmailto:krzysztof.kozlowski=40linaro.org=5D
> Sent: 03 November 2022 18:04
> To: Aakarsh Jain <aakarsh.jain=40samsung.com>; linux-arm-
> kernel=40lists.infradead.org; linux-media=40vger.kernel.org; linux-
> kernel=40vger.kernel.org; devicetree=40vger.kernel.org
> Cc: m.szyprowski=40samsung.com; andrzej.hajda=40intel.com;
> mchehab=40kernel.org; hverkuil-cisco=40xs4all.nl;
> ezequiel=40vanguardiasur.com.ar; jernej.skrabec=40gmail.com;
> benjamin.gaignard=40collabora.com; krzysztof.kozlowski+dt=40linaro.org;
> stanimir.varbanov=40linaro.org; dillon.minfei=40gmail.com;
> david.plowman=40raspberrypi.com; mark.rutland=40arm.com;
> robh+dt=40kernel.org; krzk+dt=40kernel.org; andi=40etezian.org;
> alim.akhtar=40samsung.com; aswani.reddy=40samsung.com;
> pankaj.dubey=40samsung.com; smitha.t=40samsung.com
> Subject: Re: =5BPATCH 3/3=5D arm64: dts: exynos: Rename compatible string
> property from version to SOC specific
>=20
> On 02/11/2022 09:06, Aakarsh Jain wrote:
> > commit =22752d3a23d1f68de87e3c=22 which adds MFC codec device node for
> > exynos3250 SOC. Since exynos3250.dtsi and exynos5420.dtsi are using
> > same compatible string as =22samsung,mfc-v7=22 but their node propertie=
s
> > are different.As both SoCs have MFC v7 hardware module but with
> > different clock hierarchy and complexity.
> > So renaming compatible string from version specific to SOC based.
> >
> > Suggested-by: Alim Akhtar <alim.akhtar=40samsung.com>
> > Fixes: 752d3a23d1f6 (=22ARM: dts: add MFC codec device node for
> > exynos3250=22)
>=20
> There is no bug to fix and backporting is forbidden as it breaks the usag=
e of
> DTS in older kernel.
>=20
Okay will remove this Fix tag in next series.
> > Signed-off-by: Aakarsh Jain <aakarsh.jain=40samsung.com>
> > ---
> >  arch/arm/boot/dts/exynos3250.dtsi =7C 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/arch/arm/boot/dts/exynos3250.dtsi
> > b/arch/arm/boot/dts/exynos3250.dtsi
> > index 326b9e0ed8d3..98105c64f7d9 100644
> > --- a/arch/arm/boot/dts/exynos3250.dtsi
> > +++ b/arch/arm/boot/dts/exynos3250.dtsi
> > =40=40 -485,7 +485,7 =40=40
> >  		=7D;
> >
> >  		mfc: codec=4013400000 =7B
> > -			compatible =3D =22samsung,mfc-v7=22;
> > +			compatible =3D =22samsung,exynos3250-mfc=22;
>=20
> The change is non-bisectable and breaks using DTS in older kernel.
>=20
Right, so what is your suggestion on this?
I can see two ways here:
1> To squash patch2 and patch3 in one?
2> Have a warning about this breakage in the patch-3 commit message?

> Best regards,
> Krzysztof


Thanks for the review.