linux-kernel - Re: [PATCH v5 01/16] dt-bindings: regulator: Document ROHM BD71282 regulator bindings

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Date:   Tue, 19 Nov 2019 18:51:37 +0000
From:   "Vaittinen, Matti" <Matti.Vaittinen@...rohmeurope.com>
To:     "broonie@...nel.org" <broonie@...nel.org>
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Subject: Re: [PATCH v5 01/16] dt-bindings: regulator: Document ROHM BD71282
 regulator bindings


On Tue, 2019-11-19 at 18:13 +0000, Mark Brown wrote:
> On Mon, Nov 18, 2019 at 06:03:42PM +0000, Vaittinen, Matti wrote:
> > On Mon, 2019-11-18 at 16:25 +0000, Mark Brown wrote:
> > > On Mon, Nov 18, 2019 at 08:53:57AM +0200, Matti Vaittinen wrote:
> > > I don't think I saw this having the effect on set_voltage() that
> > > I'd
> > > have expected in the driver?  
> > The support for this is added in patch 12. I should've ordered the
> > patch series so that all regulator patches were one after another.
> > Sorry for that.
> > The patch 12 adds the run-level support. Please see the functions
> > get_runcontrolled_bucks_dt(),
> > mark_regulator_runlvl_controlled() (sets the g->runlvl)
> > and set_buck_runlvl_controlled() (called based on g->runlvl)
> > which changes the ops to disallow setters and to get voltage based
> > on
> > current runlevel - and different ops depending on if runlevels are
> > controlled by GPIO or I2C. Additionally
> > set_buck_runlvl_controlled()
> > adds DT parsing call-back for setting the initial voltages.
> 
> Ah, OK.  I didn't even notice that patch when I scanned the series.
> I'll look out for this next time around but that sounds like it's
> generally going in the right direction, especially if it's integrated
> with the suspend mode regulator bindings that Chunyan did.

Probably it is not as I am not familiar with Chunyan's work. I'll try
looking what has been done on that front :) And I am pretty sure you
might not be happy with that patch - but perhaps you can give me a
nudge to better direction...

> > > > +        minimum: 0
> > > > +        maximum: 2000000
> > > > +        maxItems: 4
> > > > +        description:
> > > > +          Array of voltages for run-levels. First value is for
> > > > run-level 0,
> > > > +          second for run-level 1 etc. Microvolts.
> > > What's the mapping from array indexes to the names used elsewhere
> > > to
> > > support runlevels?
> > Hmm. Sorry Mark, I don't think I follow your question. Do you mean
> > names like LPSR, SUSPEND, IDLE, RUN? If so, then I might need to
> > rephrase this. The runlevels referred here are different from LPSR,
> > SUSPEND, IDLE etc. They are actually 'sub-levels' for PMIC's RUN
> > state.
> > Eg, kind of a 'fast way' to change voltages for multiple power
> > rails
> > when SoC is at RUN state. The names I have seen are RUN0, RUN1,
> > RUN2
> > and RUN3. That mapping is described in description above.
> 
> Yes, I think this needs clarification as I completely failed to pick
> up
> on this and did indeed read this as referring to the
> modes.  "Voltages
> that can be set in RUN mode" or something?  I take it these voltages
> are
> fixed and the OS can't change them?

Unfortunately they are not. Voltages and enable/disable statuses for
each run-level (and individually for each run-level capable buck) can
be changed at runtime via I2C. And a customer requested me also to
support this - hence the in-kernel API - but I am sure you have some
nice words when you check the patch 12. :]

Br,
	Matti Vaittinen