[U-Boot] [PATCH v2 0/7] mmc: sunxi: Enable DM_MMC

[Jagan Teki]

On Fri, Jan 18, 2019 at 11:18 PM Andre Przywara <andre.przywara at arm.com> wrote:
>
> On Fri, 18 Jan 2019 22:11:36 +0530
> Jagan Teki <jagan at amarulasolutions.com> wrote:
>
> Hi,
>
> > On Fri, Jan 18, 2019 at 6:00 PM Andre Przywara
> > <andre.przywara at arm.com> wrote:
> > >
> > > On Fri, 18 Jan 2019 07:17:41 -0500
> > > Tom Rini <trini at konsulko.com> wrote:
> > >
> > > > On Fri, Jan 18, 2019 at 11:53:49AM +0000, Andre Przywara wrote:
> > > > > On Thu, 17 Jan 2019 22:39:44 +0530
> > > > > Jagan Teki <jagan at amarulasolutions.com> wrote:
> > > > >
> > > > > > V2 for previous version[1] changes, for enabling DM_MMC
> > > > > > on Allwinner platform.
> > > > >
> > > > > So this is a neat and simple solution to the DM_MMC problem, to
> > > > > the point where I am wondering why we actually need all those
> > > > > DT driven clock and reset drivers in the first place.
> > > > > But as I understand using plat data in this way is somewhat
> > > > > frowned upon and considered deprecated (although it makes a lot
> > > > > of sense in this context).
> > > > >
> > > > > Also, isn't this series independent from the clock gates/reset
> > > > > patches? So why do you pile them on top of each other in
> > > > > sunxi/next?
> > > > >
> > > > > If we really want to have the full featured DT driven clock and
> > > > > reset support, why not use it together:
> > > > > We keep the current mod clock support in the MMC driver, but
> > > > > use the newly introduced clock gates and reset support via the
> > > > > new clock driver, mostly replacing this series. This would give
> > > > > us some test coverage of the new clock driver, while still
> > > > > avoiding to rush the MMC mod clock implementation.
> > > > >
> > > > > Does that make sense? Happy to bake some patches for that on the
> > > > > weekend.
> > > > >
> > > > > Btw: After talking to Tom on IRC, the DM_MMC deadline is
> > > > > actually _after_ the 2019.04 release, so we don't need to have
> > > > > DM_MMC support in this merge window.
> > > >
> > > > To be clearer, I plan to mark as BROKEN and start saying we're
> > > > going to remove stuff that isn't migrated, after the release.  So
> > > > it would be good to get things moved this release that can be
> > > > moved this release. Trying to use sunxi w/o MMC isn't going to be
> > > > fun :)
> > >
> > > Understood. I just gave it a quick try and it is actually quite
> > > easy: We are pretty good already regarding gate clocks and resets,
> > > with the new DM_CLK driver (v2 on the list). And using them in
> > > sunxi_mmc.c is a piece of cake and very clean.
> > > We just need to keep the MMC mod clock hack in (which this series
> > > here does as well), but can still enable DM_MMC.
> > > And for the next merge window we can tackle this by implementing the
> > > MMC mod clock properly in the clock driver, then replacing the hack
> > > with the normal clk_get_by_name(); clk_set_rate(); sequence.
> >
> > I tried with ahb clock and reset, with v2 version of CLK series and
> > it's straightforward. but mmc clock may take some time along with
> > series of testing. So I just windup this, instead of making some noise
> > at last minute.
>
> What do you mean with that, exactly?
> Do you plan to take your platdata hack for 2019.04?
> I don't like the idea of hacking something up that has no future and
> will be reverted very soon anyway. Instead we should expose the
> foundation part of the clock driver to people now for testing (as you
> did by pushing it, thanks!), but including the MMC gates and resets.
> I have this code ready, just need to test it on some SoCs this evening.
>
> I think taking this change is the best compromise between changing
> not too many things at once, yet still exposing new code to the users
> for testing.
>
> And yes, the MMC mod clock is somewhat of a beast, but if we have
> just this in the next release, it should be easier to debug than when
> we expose the whole of the new clock framework to MMC by then only.

This is I was thinking too, in fact I have created next version wrt
CLK support which may override your recent changes. May be I can
prepare and by combining both. what do you say?