[RFC] cpufreq_get()

[Ducrot Bruno <ducrot@poupinou.org>]

I'm planing to add the cpufreq_get() in struct cpufreq_driver,
but in a hardware fashion, eventually replacing the name by
something more appropriate.

Rational:
- almost all drivers that I know (powernow-k7, speedstep-*,
  longrun, and Im looking the PPC version) can implement it,
  the only one that I am aware for which it is not possible is
  the ACPI performance IO driver.

- by accessing driver->cpufreq_get() via a sysfs, we can verify if
  the 3 mains governors works.  Even for longrun, we
  can verify that the frequency is between min and max.

- we can compare /proc/cpuinfo with the result of cpufreq_get(),
  helping in debugging things.

- people may want to monitor the real frequency in their applet,
  so this help for having a more consistent API (google for 
  wmlongrun, for example).

- It is required for the ARM architecture anyway.

-- 
Ducrot Bruno

--  Which is worse:  ignorance or apathy?
--  Don't know.  Don't care.