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