[RFC] cpufreq: Add bindings for CPU clock sharing topology

[Viresh Kumar]

On 24 July 2014 07:54, Rob Herring <rob.herring at linaro.org> wrote:

>> A previous approach tried to compare struct clk pointers, which is a bad
>> idea since those are just cookies and should not be deref'd by drivers.
>> However a similar approach would be to compare the phandle, right?

Yeah. So what's the right way then?

> I think there needs to be a way to query whether a rate change for a
> clock affects other children. As pointed out previously, the clock to
> a core may not be shared, but it's parent that can change rates could
> be shared. This could be done with functions
> clk_get_parent_rate_change to return the clock in heirarchy which can
> change rates, and clk_is_parent_clk which tells if one clock is a
> child of another clock. It's been a while since I've looked at the
> clock api. It could also be done by experiment. Change the rate for
> core 0 and see if core 1's rate is changed and still equal. There's
> probably some ordering issue with doing that though.

But Mike sort of Nak'd that as well earlier :)