Messages in this thread | | | From | Michael Ellerman <> | Subject | Re: [PATCH AUTOSEL 5.12 42/43] powerpc/fsl: set fsl,i2c-erratum-a004447 flag for P2041 i2c controllers | Date | Fri, 04 Jun 2021 10:42:15 +1000 |
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Sasha Levin <sashal@kernel.org> writes: > From: Chris Packham <chris.packham@alliedtelesis.co.nz> > > [ Upstream commit 7adc7b225cddcfd0f346d10144fd7a3d3d9f9ea7 ] > > The i2c controllers on the P2040/P2041 have an erratum where the > documented scheme for i2c bus recovery will not work (A-004447). A > different mechanism is needed which is documented in the P2040 Chip > Errata Rev Q (latest available at the time of writing). > > Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz> > Acked-by: Michael Ellerman <mpe@ellerman.id.au> > Signed-off-by: Wolfram Sang <wsa@kernel.org> > Signed-off-by: Sasha Levin <sashal@kernel.org> > --- > arch/powerpc/boot/dts/fsl/p2041si-post.dtsi | 16 ++++++++++++++++ > 1 file changed, 16 insertions(+)
This patch (and the subsequent one), just set a flag in the device tree.
They have no effect unless you also backport the code change that looks for that flag, which was upstream commit:
8f0cdec8b5fd ("i2c: mpc: implement erratum A-004447 workaround")
AFAICS you haven't picked that one up for any of the stable trees.
I'll defer to Chris & Wolfram on whether it's a good idea to take the code change for stable.
I guess it's harmless to pick these two patches, but it's also pointless. So I think you either want to take all three, or drop these two.
cheers
> diff --git a/arch/powerpc/boot/dts/fsl/p2041si-post.dtsi b/arch/powerpc/boot/dts/fsl/p2041si-post.dtsi > index 872e4485dc3f..ddc018d42252 100644 > --- a/arch/powerpc/boot/dts/fsl/p2041si-post.dtsi > +++ b/arch/powerpc/boot/dts/fsl/p2041si-post.dtsi > @@ -371,7 +371,23 @@ sdhc@114000 { > }; > > /include/ "qoriq-i2c-0.dtsi" > + i2c@118000 { > + fsl,i2c-erratum-a004447; > + }; > + > + i2c@118100 { > + fsl,i2c-erratum-a004447; > + }; > + > /include/ "qoriq-i2c-1.dtsi" > + i2c@119000 { > + fsl,i2c-erratum-a004447; > + }; > + > + i2c@119100 { > + fsl,i2c-erratum-a004447; > + }; > + > /include/ "qoriq-duart-0.dtsi" > /include/ "qoriq-duart-1.dtsi" > /include/ "qoriq-gpio-0.dtsi" > -- > 2.30.2
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