[PATCH V7 2/3] OPP: Allow multiple OPP tables to be passed via DT
sboyd at codeaurora.org
Fri Jun 19 11:44:03 PDT 2015
On 06/18, Viresh Kumar wrote:
> On 17-06-15, 18:30, Stephen Boyd wrote:
> > An operating-point(s?)-names property seems ok... but doesn't that mean
> > that every CPU that uses the OPP has to have the same list of
> > operating-point-names?
> Why do you think so? For me the operating-points-v2-names property
> will be present in CPU node (as there is no OPP node which can have
> it) and so every CPU is free to choose what it wants to.
> > It would make sense to me if the operating points
> > were called something different depending on *which* CPU is using them,
> > but in this case the only name for the operating point is "slow" or
> > "fast", etc.
> I am completely confused now. :)
As am I.
> The problem you stated now was there with the current state of
> bindings. The name is embedded into the OPP table node and so is fixed
> for all the CPUs. Moving it to the CPU node will give all CPUs a
> chance to name it whatever they want to. And the same list has to be
> replicated to all CPUs sharing the clock rails.
Yes I don't see how the name will be different for any CPU, hence
my complaint/question about duplicate names in each CPU. I guess
it isn't any worse than clock-names though so I'm fine with it.
> > In reality we've assigned them names like speedX-binY-vZ so that we know
> > which speed bin, voltage bin, and version they're part of. Maybe OPP
> > node properties like qcom,speed-bin = <u32>, qcom,pvs-bin = <u32>, etc.
> > would be better?
> Lets see, only if we can't get the generic stuff for this.
> > At the least, operating-points-names will be required on qcom platforms.
> > A fixed ordering known to the platform would mean that we know exactly
> > how many voltage bins and speed bins and how many voltage bins per speed
> > bin are used for a particular SoC, which we've avoided knowing so far.
> What are we referring to fixed ordering? If we have both a list of
> phandles to OPP tables and a list of names, they can be rearranged in
> whatever fashion we want. Isn't it?
This is a reply to Rob's question about fixed ordering without a
names property. That's unlikely to work out for qcom chips.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project
More information about the linux-arm-kernel