On Wed, Sep 27, 2017 at 09:33:00AM +0200, Gregory CLEMENT wrote: > Hi Chris, > > On mer., sept. 27 2017, Chris Packham <Chris.Packham@xxxxxxxxxxxxxxxxxxx> wrote: > > > Hi Gregory, > > > > On 27/09/17 00:56, Gregory CLEMENT wrote: > >> Hi Kalyan, > >> > >> Please try avoid top-posting. > >> > >> On dim., sept. 24 2017, Kalyan Kinthada <Kalyan.Kinthada@xxxxxxxxxxxxxxxxxxx> wrote: > >> > >>> Hi Gregory, > >>> > >>> I got this information from Armada-38x functional errata document. > >> > >> OK but in any case just adding a new compatible was not enough you have > >> to update the driver in the same time, however for this case we won't > >> need it, see below. > >> > >>> > >>> I can add the "marvell,mv78230-i2c" compatible string to the appropriate device tree files > >>> but the i2c-mv64xxx driver enables an additional feature (offload i2c transactions) > >>> based on the compatible string "marvell,mv78230-i2c". > >>> > >>> I am not sure if this feature (offload i2c transactions) should be enabled for Armada-38x devices. > >>> That is the reason I felt for the need of a new compatible string > >>> specifically for Armada-38x SoCs. > >> > >> Indeed the Armada-38x SoCs does not support hardware offloading (at > >> least according the datasheet). But it happens that in the earlier > >> version of the Armada XP the hardware offloading was buggy, so we > >> introduced a compatible for this case: marvell,mv78230-a0-i2c. This > >> compatible enable the errata fix but not the offloading feature. That > >> means that it is exactly the compatible you need for Armada 38x (and > >> Armada 39x and 375 I think). > > > > The "mv78230-a0-i2c" dt-binding has the following note > > > > Note: Only use "marvell,mv78230-a0-i2c" for a > > very rare, initial version of the SoC which > > had broken offload support. Linux > > auto-detects this and sets it appropriately. > > > > If we are going to re-use this binding for armada-38x we should probably > > remove this note. Personally my preference would be an armada-38x > > Updating the documentation is the right thing to do yes. > > > > compatible string (or 370 if that's the common base of these SoCs). But > > of course we'll go with whatever your preference is as maintainer. > > If the IP is compatible then there is no reason to add a new one, else > we will end with a compatible for each SoC and the compatible property > will just loose its meaning. If you all had added compatibles for each SoC in the first place, then we wouldn't be having this dicussion. Rob
