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

[Richard Zhao]

Hi Russel,

On 3 January 2012 17:06, Russell King - ARM Linux
<linux at arm.linux.org.uk> wrote:
> 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:
>> > 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.
>
> That's because it's often not known - especially in the case of PLLs,
> data sheets don't tend to specify how long it takes for the PLL to relock
> after a requested change.  If it's important that the PLL be locked,
> there will be a bit to poll (or they'll cause the CPU itself to stall
> while the PLL is not locked.)
>
> So, for these kinds of situations, how do you suggest that the clk API
> provides this information?
In latest v6 version, I get clk transition latency from dt property, and get
regulator transition latency from regulator API.
Could you please help review other arm common changes in v6 version?

Thanks
Richard