Messages in this thread | | | Date | Thu, 10 Jun 2021 18:00:37 -0400 | From | Sasha Levin <> | Subject | Re: [PATCH AUTOSEL 5.12 42/43] powerpc/fsl: set fsl,i2c-erratum-a004447 flag for P2041 i2c controllers |
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On Fri, Jun 04, 2021 at 12:58:54AM +0000, Chris Packham wrote: > >On 4/06/21 12:42 pm, Michael Ellerman wrote: >> 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") > >That change itself isn't cherry-pick able without > >65171b2df15e ("i2c: mpc: Make use of i2c_recover_bus()") > >and in between 65171b2df15e and 8f0cdec8b5fd are a bunch of cleanups and >a fairly major rewrite which may also affect the cherry-pick ability. > >> 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. > >We have been doing some extra QA on our end for the "i2c: mpc: Refactor >to improve responsiveness" and "P2040/P2041 i2c recovery erratum" series >which hasn't thrown up any issues. But it's still a lot of new code and >at some point we're going to run into API changes. > >Given the fact that it's starting to snowball one might err on the side >of caution. > >> 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. > >At a minimum you need > >65171b2df15e ("i2c: mpc: Make use of i2c_recover_bus()") >8f0cdec8b5fd ("i2c: mpc: implement erratum A-004447 workaround") >7adc7b225cdd ("powerpc/fsl: set fsl,i2c-erratum-a004447 flag for P2041 >i2c controllers") >19ae697a1e4e ("powerpc/fsl: set fsl,i2c-erratum-a004447 flag for P1010 >i2c controllers")
I'll take the two additional commits, thanks!
-- Thanks, Sasha
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