Date:   Tue, 28 Nov 2017 16:50:32 +0100
From:   Ulf Hansson <ulf.hansson@...aro.org>
To:     Viresh Kumar <viresh.kumar@...aro.org>
Cc:     Kevin Hilman <khilman@...nel.org>,
        Viresh Kumar <vireshk@...nel.org>, Nishanth Menon <nm@...com>,
        Stephen Boyd <sboyd@...eaurora.org>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        "linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Rob Herring <robh+dt@...nel.org>,
        Rajendra Nayak <rnayak@...eaurora.org>,
        Sudeep Holla <sudeep.holla@....com>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [RFC V7 1/2] OPP: Allow OPP table to be used for power-domains

On 31 October 2017 at 13:47, Viresh Kumar <viresh.kumar@...aro.org> wrote:
> Power-domains can also have their active states and this patch enhances
> the OPP binding to define those.
>
> The power domains can use the OPP bindings mostly as is. Though there
> are some changes required to support special cases:
>
> - Allow "operating-points-v2" to contain multiple phandles for power
>   domain providers providing multiple domains.
>
> - A new property "power-domain-opp" is added for devices to specify the
>   minimum required OPP of the master domain for the functioning of the
>   device. We can add this property directly to device's node if the
>   device has a fixed minimum OPP requirement from the master power

Please avoid the terminology "master power domain", it's confusing.
Instead use only "power domain". This applies to a couple of more
places of $subject patch, please fix those as well.

>   domain. Or we can add this property to each OPP node of the device, if
>   different OPP nodes have different minimum OPP requirement from the
>   master power domain.
>
> Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>
> ---
>  Documentation/devicetree/bindings/opp/opp.txt      | 12 +++++
>  .../devicetree/bindings/power/power_domain.txt     | 62 ++++++++++++++++++++++
>  2 files changed, 74 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/opp/opp.txt b/Documentation/devicetree/bindings/opp/opp.txt
> index 9d733af26be7..203e09fe7698 100644
> --- a/Documentation/devicetree/bindings/opp/opp.txt
> +++ b/Documentation/devicetree/bindings/opp/opp.txt
> @@ -45,6 +45,11 @@ Devices supporting OPPs must set their "operating-points-v2" property with
>  phandle to a OPP table in their DT node. The OPP core will use this phandle to
>  find the operating points for the device.
>
> +This can contain more than one phandle for power domain providers that provide
> +multiple power domains. That is, one phandle for each power domain. If only one
> +phandle is available, then the same OPP table will be used for all power domains
> +provided by the power domain provider.
> +
>  If required, this can be extended for SoC vendor specific bindings. Such bindings
>  should be documented as Documentation/devicetree/bindings/power/<vendor>-opp.txt
>  and should have a compatible description like: "operating-points-v2-<vendor>".
> @@ -154,6 +159,13 @@ properties.
>
>  - status: Marks the node enabled/disabled.
>
> +- 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).
> +  This property can only be set for a device if the device node contains the
> +  "power-domains" property. Also, either all or none of the OPP nodes in an OPP
> +  table should have it set.
> +
>  Example 1: Single cluster Dual-core ARM cortex A9, switch DVFS states together.
>
>  / {
> diff --git a/Documentation/devicetree/bindings/power/power_domain.txt b/Documentation/devicetree/bindings/power/power_domain.txt
> index 14bd9e945ff6..0d8608f2d133 100644
> --- a/Documentation/devicetree/bindings/power/power_domain.txt
> +++ b/Documentation/devicetree/bindings/power/power_domain.txt
> @@ -40,6 +40,12 @@ phandle arguments (so called PM domain specifiers) of length specified by the
>    domain's idle states. In the absence of this property, the domain would be
>    considered as capable of being powered-on or powered-off.
>
> +- operating-points-v2 : Phandles to the OPP tables of power domains provided by
> +  a power domain provider. If the provider provides a single power domain only
> +  or all the power domains provided by the provider have identical OPP tables,
> +  then this shall contain a single phandle. Refer to ../opp/opp.txt for more
> +  information.
> +
>  Example:
>
>         power: power-controller@...40000 {
> @@ -120,4 +126,60 @@ The node above defines a typical PM domain consumer device, which is located
>  inside a PM domain with index 0 of a power controller represented by a node
>  with the label "power".
>
> +Optional properties:
> +- 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. This property can only be set for a device, if
> +  the device node contains the "power-domains" property.
> +
> +Example:
> +- OPP table for domain provider that provides two domains.
> +
> +       domain0_opp_table: opp_table0 {
> +               compatible = "operating-points-v2";
> +
> +               domain0_opp_0: opp-1000000000 {
> +                       opp-hz = /bits/ 64 <1000000000>;
> +                       opp-microvolt = <975000 970000 985000>;
> +               };
> +               domain0_opp_1: opp-1100000000 {
> +                       opp-hz = /bits/ 64 <1100000000>;
> +                       opp-microvolt = <1000000 980000 1010000>;
> +               };
> +       };
> +
> +       domain1_opp_table: opp_table1 {
> +               compatible = "operating-points-v2";
> +
> +               domain1_opp_0: opp-1200000000 {
> +                       opp-hz = /bits/ 64 <1200000000>;
> +                       opp-microvolt = <975000 970000 985000>;
> +               };
> +               domain1_opp_1: opp-1300000000 {
> +                       opp-hz = /bits/ 64 <1300000000>;
> +                       opp-microvolt = <1000000 980000 1010000>;
> +               };
> +       };
> +
> +       parent: power-controller@...40000 {
> +               compatible = "foo,power-controller";
> +               reg = <0x12340000 0x1000>;
> +               #power-domain-cells = <1>;
> +               operating-points-v2 = <&domain0_opp_table>, <&domain1_opp_table>;
> +       };
> +
> +       leaky-device0@...50000 {
> +               compatible = "foo,i-leak-current";
> +               reg = <0x12350000 0x1000>;
> +               power-domains = <&parent 0>;
> +               power-domain-opp = <&domain0_opp_0>;
> +       };
> +
> +       leaky-device1@...50000 {
> +               compatible = "foo,i-leak-current";
> +               reg = <0x12350000 0x1000>;
> +               power-domains = <&parent 1>;
> +               power-domain-opp = <&domain1_opp_1>;
> +       };
> +
>  [1]. Documentation/devicetree/bindings/power/domain-idle-state.txt
> --

Besides the minor nitpick(s), this looks good to me. Feel free to add:

Reviewed-by: Ulf Hansson <ulf.hansson@...aro.org>

Kind regards
Uffe

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