Re: [cip-dev] [PATCH RESEND 4.4.y-cip 03/15] PM / OPP: Add {opp-microvolt|opp-microamp}-<name> binding

["Pavel Machek" <pavel@ucw.cz>]

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Hi!

> From: Viresh Kumar <viresh.kumar@linaro.org>
> 
> commit ffdb8cc7a27c89175e541e68e2a73f1f63ab8c6b upstream.
> 
> Depending on the version of hardware or its properties, which are only
> known at runtime, various properties of the OPP can change. For example,
> an OPP with frequency 1.2 GHz, may have different voltage/current
> requirements based on the version of the hardware it is running on.
> 
> In order to not replicate the same OPP tables for varying values of all
> such fields, this commit introduces the concept of opp-property-<name>.
> The <name> can be chosen by the platform at runtime, and OPPs will be
> initialized depending on that name string. Currently support is extended
> for the following properties:
> - opp-microvolt-<name>
> - opp-microamp-<name>

That's really quite "interesting" design. I wondered if devicetree
people are okay with that.

> If the name string isn't provided by the platform, or if it is provided
> but doesn't match the properties present in the OPP node, we will fall
> back to the original properties without the -<name> string, if they are
> available.
> 
> Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> Signed-off-by: Chen-Yu Tsai (Moxa) <wens@csie.org>

But, interestingly, their review tag is missing...?

As this is mainline, I don't think we need to do anything here. I
wonder how this kind of "wildcard" property names will play with new
yml format or automatic device tree checks.

Best regards,
								Pavel

> +++ b/Documentation/devicetree/bindings/opp/opp.txt
> @@ -100,6 +100,14 @@ Optional properties:
>    Entries for multiple regulators must be present in the same order as
>    regulators are specified in device's DT node.
>  
> +- opp-microvolt-<name>: Named opp-microvolt property. This is exactly similar to
> +  the above opp-microvolt property, but allows multiple voltage ranges to be
> +  provided for the same OPP. At runtime, the platform can pick a <name> and
> +  matching opp-microvolt-<name> property will be enabled for all OPPs. If the
> +  platform doesn't pick a specific <name> or the <name> doesn't match with any
> +  opp-microvolt-<name> properties, then opp-microvolt property shall be used, if
> +  present.
> +
>  - opp-microamp: The maximum current drawn by the device in microamperes
>    considering system specific parameters (such as transients, process, aging,
>    maximum operating temperature range etc.) as necessary. This may be used to

-- 
DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany

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