Re: U-Boot sunxi DM_I2C migration?

[Tom Rini <trini@konsulko.com>]

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On Thu, Aug 12, 2021 at 05:40:34PM -0400, Tom Rini wrote:
> On Thu, Aug 12, 2021 at 10:22:07PM +0100, Andre Przywara wrote:
> > On Thu, 12 Aug 2021 13:49:30 -0400
> > Tom Rini <trini@konsulko.com> wrote:
> > 
> > Hi Tom,
> > 
> > > As I try and migrate more CONFIG symbols to be Kconfig only, I see that
> > > sunxi is still using the legacy I2C drivers.  Is there something
> > > specific holding up migration?  Thanks!
> > 
> > Do you mean a DM_I2C conversion, or just moving those base address
> > symbols to Kconfig? The latter is rather easy, let me know if I should
> > give it a shot.
> > 
> > For DM_I2C, it's the usual sunxi issue: we are using both: DM_I2C and
> > DT based probing for U-Boot proper, and hardcoded CONFIG_ symbols for
> > the SPL. *Some* boards need the set up the PMIC early (for increasing
> > the CPU frequency or setting the proper DRAM voltage), so this needs to
> > be done in the SPL. I don't know how to fix this "properly",
> > but introducing DM (and DT) into the SPL is surely not worth the
> > trouble. Alternatively we could have a separate, cut-down SPL-only
> > driver, like we have for SPI (arch/arm/mach-sunxi/spl_spi_sunxi.c),
> > but not sure that's really better.
> > 
> > If there is something in particular that annoys you about the
> > situation, we could try to improve this particular issue instead?
> > Moving the non-DM code into a separate file, maybe?
> 
> I'm working on the symbols now (since it gets tricky).  The first
> example I pulled out was Hummingbird_A31 which does have legacy I2C and
> does not set DM_I2C, which is what set me down the more worrying path.
> If you can confirm that no, really, it's just SPL that's not using
> DM_I2C that's OK enough for now, we can sort out what the best but
> probably still unideal solution is long term for SPL.

As I'm converting the symbols to Kconfig now (and adding
SPL_SYS_I2C_LEGACY), what I'm seeing on sunxi is a whole lot of platform
enabling the legacy driver in full U-Boot and not DM_I2C.  Now it's
entirely possible the follow up solution really is just to switch to
DM_I2C (and continue SPL_SYS_I2C_LEGACY) and it would be a fairly
trivial switch.  But I'm not in a good position to make that change and
test it, so I'm asking you to please, once I've posted this series to
add SPL_SYS_I2C_LEGACY

-- 
Tom

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