Hi Geert and Laurent, On 2017-04-20 13:47:19 +0200, Geert Uytterhoeven wrote: > Hi Laurent, > > On Thu, Apr 20, 2017 at 1:44 PM, Laurent Pinchart > <laurent.pinch...@ideasonboard.com> wrote: > > On Thursday 20 Apr 2017 13:37:27 Geert Uytterhoeven wrote: > >> On Thu, Apr 20, 2017 at 12:18 PM, Laurent Pinchart wrote: > >> > On Thursday 20 Apr 2017 12:11:41 Geert Uytterhoeven wrote: > >> >> On Thu, Apr 20, 2017 at 12:02 PM, Laurent Pinchart wrote: > >> >>> On Thursday 20 Apr 2017 11:49:06 Geert Uytterhoeven wrote: > >> >>>> Group the AVB pins into similar groups as found in other > >> >>>> sh-pfc > >> >>>> drivers. The pins can not be muxed between functions other than AVB, > >> >>>> but their drive strengths can be controlled. > >> >>>> > >> >>>> The group avb_mdc containing ADV_MDC and ADV_MDIO is called avb_mdio > >> >>>> on other SoCs. In pfc-r8a7796 the avb_mdc group already existed and is > >> >>>> in use in DT. Therefore add the ADV_MDIO pin to the existing group > >> >>>> instead of renaming it. > >> >>> > >> >>> This clearly shows that we need a few kernel releases to test > >> >>> PFC-related code and DT before we can commit to an ABI. How do you > >> >>> think we should handle this ? > >> >> > >> >> That's a difficult question > >> >> > >> >> For now I'd like to treat R-Car M3-W the same as H3. > >> > > >> > I still believe we should introduce some kind of unstable period for DT > >> > bindings, during which they will be merged in mainline but still subject > >> > to modification. It could just be a few kernel releases. > >> > >> Like, from v4.4 (when avb_mdc was added for H3) until v4.12 (earliest > >> we can correct this)? > > > > Sorry, I misread you, I thought that H3 named the group mdio (you might want > > to clarify this in the commit message). I was referring to when M3 PFC > > support > > Sorry, this was a bit unclear (I reused the description from the H3 patch). > This was actually referring to R-Car Gen2. Will fix. > > > was introduced, which was v4.10, so that's just two releases. We obviously > > can't rename mdc to mdio on H3 if we want to keep backward compatibility. > > And because of pin-compatibility and board sharing of H3 and M3-W, I > want both to use identical group naming.
I also think it's a benefit if the group names are identical on H3 and M3-W. And I think it is unfortunate that the name do not match Gen2 naming. When adding the pins to r8a7795 I thought of instead adding AVB_MDIO to the group avb_mdc add a new group with the Gen2 naming (avb_mdio) and add both AVB_MDC and AVB_MDIO to this group but still also keep the group avb_mdc. If I had done that it would be compatible with Gen2 naming and backward compatible with old H3 DT. Maybe I was wrong of not doing it like this and perhaps that solution should be revisited? That is keep avb_mdc as is on H3 for backward compatibility but add avb_mdio to both H3 and M3-W and update H3 DT to use avb_mdio. In any case I reviewed the pins as it is identical to how it's done on H3. So if you choose to move forward with this approach feel free to add: Reviewed-by: Niklas Söderlund <niklas.soderlund+rene...@ragnatech.se> > > Gr{oetje,eeting}s, > > Geert > > -- > Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- > ge...@linux-m68k.org > > In personal conversations with technical people, I call myself a hacker. But > when I'm talking to journalists I just say "programmer" or something like > that. > -- Linus Torvalds > -- > To unsubscribe from this list: send the line "unsubscribe linux-gpio" in > the body of a message to majord...@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- Regards, Niklas Söderlund