[RFC 0/5] drivers: Add boot constraints core

Viresh Kumar
2017-06-30T03:55:33Z

On 30-06-17, 11:33, Chen-Yu Tsai wrote:
> AFAIK regulator constraints are supposed to satisfy all users of it.

Right.

> >> >Let me try with an example. A regulator is shared between LCD and DMA
> >> >controller.
> >> >
> >> >Operable ranges of the regulator: 1.8 - 3.0 V
> >> >Range required by LCD: 2.0 - 3.0 V
> >> >Range required by DMA: 1.8 - 2.5 V
>
> So for the example here, the regulator constraint should be 2.5 - 3.0 V,
> or the intersection of all voltage requirements.

Had a look at regulator_check_consumers() and the range selected by it
is the *highest* min_uV and *lowest* max_uV, to find that intersection
point.

For LCD: min_uV = 2.0 V, max_uV = 3.0 V
For DMA: min_uV = 1.8 V, max_uV = 2.5 V

Highest min_uV = 2.0 V
Lowest max_uV = 2.5 V

And so I mentioned the regulator's final range (that satisfies all
consumers) is 2 - 2.5 V.

Why do you say it should be 2.5 - 3.0 V ?

--
viresh