Re: [PATCH 01/13] clk: tegra: Add binding for the Tegra124 DFLL clocksource

[Tuomas Tynkkynen]

On 11/07/14 20:08, Andrew Bresticker wrote:
> On Fri, Jul 11, 2014 at 9:48 AM, Tuomas Tynkkynen <ttynkkynen@xxxxxxxxxx> wrote:
> > On 11/07/14 19:28, Andrew Bresticker wrote:
> > > On Thu, Jul 10, 2014 at 2:42 PM, Tuomas Tynkkynen <ttynkkynen@xxxxxxxxxx>
> > > wrote:
> > > > The DFLL is the main clocksource for the fast CPU cluster on Tegra124
> > > > and also provides automatic CPU rail voltage scaling as well. The DFLL
> > > > is a separate IP block from the usual Tegra124 clock-and-reset
> > > > controller, so it gets its own node in the device tree.
> > >
> > >
> > > > diff --git
> > > > a/Documentation/devicetree/bindings/clock/nvidia,tegra124-dfll.txt
> > > > b/Documentation/devicetree/bindings/clock/nvidia,tegra124-dfll.txt
> > >
> > >
> > > > +- nvidia,pmic-voltage-table: Array of 2-tuples.  Each entry should have
> > > > the
> > > > +  form <register-value voltage-in-uV>, indicating the register value
> > > > that
> > > > +  needs to be programmed to the PMIC for changing the VDD_CPU voltage to
> > > > +  the specified voltage. The table must be in ascending order by the
> > > > voltage.
> > >
> > >
> > > Instead of listing the register values for each voltage in the DT,
> > > can't you use regulator_list_voltage() to create this map?
> >
> > I don't see a way to get the register values that way, unless we assume that
> > the mapping is linear and doesn't have holes.
>
> Hmm... I guess if you don't assume it's linear and continuous you'd
> have to iterate over all 256 selectors.

I don't think we can assume that each selector maps to a concrete 
register value, though I'm not sure. include/linux/regulator/driver.h 
documents for @list_voltage "Selectors range from zero to one less 
regulator_desc.n_voltages." but maybe the consumer API could take 
different values.

--
nvpublic
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