Re: [PATCH 1/3] PM / OPP: Add "opp-supported-hw" binding

From: Stephen Boyd
Date: Fri Oct 30 2015 - 17:49:16 EST

On 10/30, Viresh Kumar wrote:
> +- opp-supported-hw: User defined array containing a hierarchy of hardware
> + version numbers, supported by the OPP. For example: a platform with hierarchy
> + of three levels of versions (A, B and C), this field should be like <X Y Z>,
> + where X corresponds to Version hierarchy A, Y corresponds to version hierarchy
> + B and Z corresponds to version hierarchy C.
> +
> + Each level of hierarchy is represented by a 32 bit value, and so there can be
> + only 32 different supported version per hierarchy. i.e. 1 bit per version. A
> + value of 0xFFFFFFFF will enable the OPP for all versions for that hierarchy
> + level. And a value of 0x00000000 will disable the OPP completely, and so we
> + never want that to happen.

I suppose if you wanted to have 64 possible combinations of some
attribute you would just extend it to two 32 bit numbers in
sequence? I don't see the limitation here, and hopefully there
isn't a limitation so that we can specify sufficiently large
numbers with more bits if we need to.

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