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SubjectRe: [RFC V7 1/2] OPP: Allow OPP table to be used for power-domains
On Tue, Oct 31, 2017 at 7:47 AM, Viresh Kumar <viresh.kumar@linaro.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
> 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@linaro.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.

This is a "this device requires OPP n" property. Couldn't we want this
for cases other than a powerdomain OPP? What if a device has
requirements 2 different OPPs?

On the flipside, I don't think we want devices picking things like CPU
OPPs and putting policy here. But I'd rather things be extendable than
reviewing yet another OPP property next month.

Rob

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