Re: [RFC V7 2/2] OPP: Allow "opp-hz" and "opp-microvolt" to contain magic values

[Ulf Hansson]

On 2 November 2017 at 10:00, Viresh Kumar <viresh.kumar@xxxxxxxxxx> wrote:
> On 02-11-17, 00:15, Stephen Boyd wrote:
>> Sorry I'm not following. We're going to need to have platform
>> specific code that understands platform specific bindings that
>> aren't shoved into the generic OPP bindings.
>
> At least I am not targeting any platform specific binding right now.
> The way I see this to work is:
>
> - We will reuse earlier bindings and allow opp-hz and opp-microvolt to
>   contain special values (this patch).
> - Platform specific DT entries will put corner numbers in opp-hz (or
>   opp-microvolt) fields.
> - Some platform specific driver (in OPP or genpd) will be used to
>   convert OPP into a performance state (corner) value. Now that can
>   simply read opp-hz (or opp-microvolt) and return its value.

Since the "operating-points-v2" phandle(s) belongs in the power-domain
controller device node, which anyway is being parsed by the genpd SoC
specific driver, I assume it makes sense to start the initialization
from there. Unless there is something that prevents that, of course.

Then whatever library/helper functions we need for parse and create
the OPP tables, can be provided to the OPP framework and the OPP OF
library.

> - OPP core will request for a performance state (code is already
>   merged for that).
>
> And so there is no platform specific binding here. Do you want to do
> this differently ?

This makes sense to me!

Also, the SoC (QCOM) specific genpd driver is free to use the
terminology "corner values", when it translates opp-hz|microvolt into
such values.

Kind regards
Uffe