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    SubjectRe: [PATCH V4 1/9] PM / OPP: Allow OPP table to be used for power-domains
    On 12-04-17, 17:49, Sudeep Holla wrote:
    > On 20/03/17 09:32, Viresh Kumar wrote:
    > > diff --git a/Documentation/devicetree/bindings/opp/opp.txt b/Documentation/devicetree/bindings/opp/opp.txt
    > > index 63725498bd20..d0b95c9e1011 100644
    > > --- a/Documentation/devicetree/bindings/opp/opp.txt
    > > +++ b/Documentation/devicetree/bindings/opp/opp.txt
    > > @@ -76,10 +76,9 @@ This describes the OPPs belonging to a device. This node can have following
    > > This defines voltage-current-frequency combinations along with other related
    > > properties.
    > >
    > > -Required properties:
    > > +Optional properties:
    > > - opp-hz: Frequency in Hz, expressed as a 64-bit big-endian integer.
    > >
    > > -Optional properties:
    > > - opp-microvolt: voltage in micro Volts.
    > >
    > > A single regulator's voltage is specified with an array of size one or three.
    > > @@ -154,6 +153,19 @@ properties.
    > >
    > > - status: Marks the node enabled/disabled.
    > >
    > > +- domain-performance-state: A positive integer value representing the minimum
    > > + power-domain performance level required by the device for the OPP node. The
    >
    > So the above definition is when this field in in the device node rather
    > than the OPP table entry, right ?

    No. We are updating the opp.txt file here and so it is not about the
    device node. The OPP node entries will contain this field for two
    cases:
    - The OPP table belongs to a power domain
    - The OPP table belongs to a device whose power domain supports
    performance-states.

    > For simplicity why not have the
    > properties named slightly different or just use phandle to an entry in
    > the device node for this purpose.

    We really need a value here. For example, in case where the OPP table
    defines the states of the power-domain itself, we don't have any
    phandles to point to.

    > > + The integer value '0' represents the lowest performance level and the higher
    > > + values represent higher performance levels.
    >
    > needs to be changed as OPP table entry.

    Not sure I understood what change you are looking for :(

    > > When present in the OPP table of a
    > > + power-domain, it represents the performance level of the domain. When present
    >
    > again "performance level of the domain corresponding to that OPP entry"
    > on something similar

    Ok.

    > > + in the OPP table of a normal device, it represents the performance level of
    >
    > what do you mean by normal device ? needs description as that's
    > something new introduced here.

    It should be non-power-domain node.

    > > + the parent power-domain. The OPP table can contain the
    > > + "domain-performance-state" property, only if the device node contains the
    > > + "power-domains" or "#power-domain-cells" property.
    >
    > Why such a restriction ?

    Why would we use it for non-power-domain cases? That's not what we
    are looking for..

    > > The OPP nodes aren't
    > > + allowed to contain the "domain-performance-state" property partially, i.e.
    > > + Either all OPP nodes in the OPP table have the "domain-performance-state"
    > > + property or none of them have it.
    > > +
    > > Example 1: Single cluster Dual-core ARM cortex A9, switch DVFS states together.
    > >
    > > / {
    > > @@ -528,3 +540,60 @@ Example 5: opp-supported-hw
    > > };
    > > };
    > > };
    > > +
    > > +Example 7: domain-Performance-state:
    > > +(example: For 1GHz require domain state 1 and for 1.1 & 1.2 GHz require state 2)
    > > +
    > > +/ {
    > > + domain_opp_table: opp_table0 {
    > > + compatible = "operating-points-v2";
    > > +
    > > + opp@1 {
    > > + domain-performance-state = <1>;
    > > + opp-microvolt = <975000 970000 985000>;
    > > + };
    > > + opp@2 {
    > > + domain-performance-state = <2>;
    > > + opp-microvolt = <1075000 1000000 1085000>;
    > > + };
    > > + };
    > > +
    > > + foo_domain: power-controller@12340000 {
    > > + compatible = "foo,power-controller";
    > > + reg = <0x12340000 0x1000>;
    > > + #power-domain-cells = <0>;
    > > + operating-points-v2 = <&domain_opp_table>;
    >
    > How does it scale with power domain providers with multiple power domain ?

    Devices can't have multiple power domains today. Will see this when
    that support is added.

    Note that only the power domains can have multiple parent power
    domains today.

    > > + }
    > > +
    > > + cpu0_opp_table: opp_table1 {
    > > + compatible = "operating-points-v2";
    > > + opp-shared;
    > > +
    > > + opp@1000000000 {
    > > + opp-hz = /bits/ 64 <1000000000>;
    > > + domain-performance-state = <1>;
    > > + };
    > > + opp@1100000000 {
    > > + opp-hz = /bits/ 64 <1100000000>;
    > > + domain-performance-state = <2>;
    > > + };
    > > + opp@1200000000 {
    > > + opp-hz = /bits/ 64 <1200000000>;
    > > + domain-performance-state = <2>;
    > > + };
    > > + };
    > > +
    > > + cpus {
    > > + #address-cells = <1>;
    > > + #size-cells = <0>;
    > > +
    > > + cpu@0 {
    > > + compatible = "arm,cortex-a9";
    > > + reg = <0>;
    > > + clocks = <&clk_controller 0>;
    > > + clock-names = "cpu";
    > > + operating-points-v2 = <&cpu0_opp_table>;
    >
    > Do we ignore operating-points-v2 above as this device/cpu node contains
    > power domain which has operating-points-v2 property ? In other words
    > how do they correlate ?

    Devices and their power domains can both have their performance
    states. Just that to get the device in a particular state, we may need
    to get its power domain to a particular state first.

    --
    viresh

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