RE: [PATCH 3/3] arm64: dts: exynos: Rename compatible string property from version to SOC specific

["Aakarsh Jain" <aakarsh.jain@samsung.com>]

> -----Original Message-----
> From: Krzysztof Kozlowski [mailto:krzysztof.kozlowski@linaro.org]
> Sent: 03 November 2022 18:04
> To: Aakarsh Jain <aakarsh.jain@samsung.com>; linux-arm-
> kernel@lists.infradead.org; linux-media@vger.kernel.org; linux-
> kernel@vger.kernel.org; devicetree@vger.kernel.org
> Cc: m.szyprowski@samsung.com; andrzej.hajda@intel.com;
> mchehab@kernel.org; hverkuil-cisco@xs4all.nl;
> ezequiel@vanguardiasur.com.ar; jernej.skrabec@gmail.com;
> benjamin.gaignard@collabora.com; krzysztof.kozlowski+dt@linaro.org;
> stanimir.varbanov@linaro.org; dillon.minfei@gmail.com;
> david.plowman@raspberrypi.com; mark.rutland@arm.com;
> robh+dt@kernel.org; krzk+dt@kernel.org; andi@etezian.org;
> alim.akhtar@samsung.com; aswani.reddy@samsung.com;
> pankaj.dubey@samsung.com; smitha.t@samsung.com
> Subject: Re: [PATCH 3/3] arm64: dts: exynos: Rename compatible string
> property from version to SOC specific
> 
> On 02/11/2022 09:06, Aakarsh Jain wrote:
> > commit "752d3a23d1f68de87e3c" which adds MFC codec device node for
> > exynos3250 SOC. Since exynos3250.dtsi and exynos5420.dtsi are using
> > same compatible string as "samsung,mfc-v7" but their node properties
> > 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@samsung.com>
> > Fixes: 752d3a23d1f6 ("ARM: dts: add MFC codec device node for
> > exynos3250")
> 
> There is no bug to fix and backporting is forbidden as it breaks the usage of
> DTS in older kernel.
> 
Okay will remove this Fix tag in next series.
> > Signed-off-by: Aakarsh Jain <aakarsh.jain@samsung.com>
> > ---
> >  arch/arm/boot/dts/exynos3250.dtsi | 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
> > @@ -485,7 +485,7 @@
> >  		};
> >
> >  		mfc: codec@13400000 {
> > -			compatible = "samsung,mfc-v7";
> > +			compatible = "samsung,exynos3250-mfc";
> 
> The change is non-bisectable and breaks using DTS in older kernel.
> 
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.