Hi Fabio, On Fri, May 14, 2021 at 9:30 AM Fabio Estevam <feste...@gmail.com> wrote: > > Hi Andrey, > > On Wed, May 12, 2021 at 6:47 PM ZHIZHIKIN Andrey > <andrey.zhizhi...@leica-geosystems.com> wrote: > > > > Update PMIC to use PCA9540, the legacy board not supported by NXP > > > > This commit seems rather a "nuclear" to me, as de-facto it drops the > > initialization of ROMH PMIC in > > favor of PCA one, leaving all the previous board revisions not to be > > properly sourced. > > > > I know that there might be no intention to provide a support for earlier > > revisions of i.MX8M Mini > > EVKs from NXP, but providing no backward compatibility to those boards > > which are still in use by > > a lot of people for development purposes is highly undesirable either. > > > > TBH, I've tested this patch on the old EVK where ROMH PMIC is present, and > > apart from having some > > error messages in SPL regarding the register writes - it does boots. What > > worries me the most though > > is that DTS changes some voltage settings, which I'm not sure how the SOC > > would react on. > > > > To my opinion, this patch should either be complemented with the mechanism > > to provide a > > level of backward compatibility (where the PMIC can be dynamically > > identified and instantiated), > > or the separate implementation should be presented which would make the old > > board type not to > > be bootable at all if it is considered not to be supported any longer. Or > > this patch should be reverted > > in an effort to come up with a solution which covers new revision without > > "damaging" the currently > > integrated one. > > > > Fabio / Stefano, > > Do you have any thoughts here on how this should be handled further, > > considering the fact that the > > backward compatibility of 2021.07 release is not kept for this board type > > across multiple revisions? > > > > I'd really like to get your opinion here as I do have those boards in > > development and would need to > > come up with the idea on what to do with them. > > > > Also, this should be taken care of in the Yocto, since there is only one > > definition of the i.MX8MM EVK > > machine which does not make any distinction regarding the revision. > > You bring a good point. > > What about adding a new defconfig to support the old imx8mm-evk with > the Rohm PMIC? > > Then we could have imx8mm_evk_defconfig for the new version and > imx8mm_evk_rohm_defconfig for the old one. > > What do you think?
Maybe a dynamic way to identify if BD71837 or PCA9450 (by probing i2c) would work better? Different configs would imply different builds and binaries, which is a problem when trying to support a single build for both the old EVK and EVKB (and the main difference is the PMIC, nothing really major). I also share Andrey's concerns, as we do have several EVKs in hands, and having one single build would facilitate quite a bit. Cheers, -- Ricardo Salveti de Araujo
