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SubjectRe: [RFC V7 2/2] OPP: Allow "opp-hz" and "opp-microvolt" to contain magic values
On 27-12-17, 15:36, Rob Herring wrote:
> On Tue, Dec 26, 2017 at 10:45 PM, Viresh Kumar <viresh.kumar@linaro.org> wrote:
> > On 26-12-17, 14:23, Rob Herring wrote:
> >> > cpu_opp_table: cpu_opp_table {
> >> > compatible = "operating-points-v2";
> >> > opp-shared;
> >> >
> >> > opp00 {
> >> > opp-hz = /bits/ 64 <208000000>;
> >> > clock-latency-ns = <500000>;
> >> > power-domain-opp = <&domain_opp_1>;
> >>
> >> What is this? opp00 here is not a device. One OPP should not point to
> >> another. "power-domain-opp" is only supposed to appear in devices
> >> alongside power-domains properties.
> >
> > There are two type of devices:
> >
> > A.) With fixed performance state requirements and they will have the
> > new "required-opp" property in the device node itself as you said.
> >
> > B.) Devices which can do DVFS (CPU, MMC, LCD, etc) and those may need
> > a different performance state of the domain for their individual OPPs
> > and so we can't have this property in the device all the time.
> >
> > Does this make sense ?
>
> No. From the definition for power-domain-opp
>
> "+- power-domain-opp: This contains phandle to one of the OPP nodes of
> the master
> + power domain. This specifies the minimum required OPP of the master
> domain for
> + the functioning of the device in this OPP (where this property is present).

The per-opp thing was mentioned here.

> + This property can only be set for a device if the device node contains the
> + "power-domains" property.

This was trying to say something else, though it wasn't clear and so your
concerns.

I wanted to say that the device node or its OPP nodes can have the
"power-domain-opp" property only if the device node has a "power-domains"
property. i.e. you need to have power domain first and then only the
power-domain-opp property.

> Also, either all or none of the OPP nodes in an OPP
> + table should have it set."
>
> In the above example, you are violating the next to last sentence.
>
> Though, I'm now confused by what the last sentence means.

Yeah, lets leave it as is as the V8 has changed this significantly and you
already Acked it :)

--
viresh

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