[PATCH v4 4/7] cpufreq: add clk-reg cpufreq driver

Mark Brown broonie at opensource.wolfsonmicro.com
Mon Dec 26 09:22:34 EST 2011

On Mon, Dec 26, 2011 at 09:44:52PM +0800, Richard Zhao wrote:
> On Mon, Dec 26, 2011 at 11:10:30AM +0000, Mark Brown wrote:

Fix your mailer to word wrap properly please.

> > The *call* is there in the regulator subsystem, it's just that none of
> > the drivers back it up with an actual implementation yet.  Which turns
> > out to be a good thing as cpufreq can't currently understand variable
> > latencies and the governors don't deal well with non-trivial latencies
> > anyway.

> but clk API don't have such calls. and many SoCs only adjust clk
> frequencies, using one single voltage.

I've not suggested doing this in the clock API, only for the regulator.
For the clocks it's less clear that it's useful as you don't have the
bulk operations and it's much rarer to need them.

> > The problem with device tree is that once you've defined a binding
> > you're stuck with it, it's very hard to change - witness all the magic
> > number based stuff with the interrupt bindings for example

> So what's your suggestion? We can not set transition_latency to set
> random number.

As I've repeatedly said I think you should define it to be the latency
for the SoC only, not for the regulators.

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