What's changed highlights:
- PowerOP Core is completely arch independent
- PowerOP Core provides interface to create/destroy, get/set
operating points
- PowerOP Core maintains list of operating points which can
be referenced by names
- PowerOP Core allows an upper layer to operate on arbitrary
subset of power parameters available on a certain platform
- More integration with cpufreq and omap cpufreq driver clean up
(hw access code is removed)
PowerOP is a system power parameter management API submitted for
discussion.
This patch set is a follow-up to the PowerOP/cpufreq integration
discussion in the PM summit back in April and the continued discussion
of the small PM group and linux-pm list.
Overall proposed PM framework picture is the following:
user space
-----------------------------------------------------------------
---------- kernel space
| CPU freq |
----------
^
|
v
------------------------
| PowerOP |
-------------------------
arch independent
------------------------------------------------------------------------
arch specific
--------------------------
| PM Core |
-------------------------
------------------------------
| Clock/Voltage FW |
------------------------------
In the whole, PowerOP is designed to be completely arch independent
and and allows to create, write and read power parameters in a
form adopted by a layer above PowerOP (cpufreq for example).
PM Core provides access to all power parameters available on a
certain platform and in a pair with PowerOP allows for a power
control layer above PowerOP operates by arbitrary subset of
power parameters (cpufreq for ex. uses 2 out of 8 power parameters
available on an omap1 platform what will be shown in follow-up
patch but one can imaging other layer which utilize from 1 upto 8
power parameters).
Nowadays Linux has clock framework - well established interface to access
hw clocks and the layer which handles clocks interdependencies. Similar
voltage framework is on the way. Such combined clock/voltage framework
provides a good interface to get/set clock and voltage hw registers.
Clock/voltage framework utilization gives significant advantage in
power management providing dynamic clocks/voltages control in
addition to "on demand" power parameters settings capability provided by
PowerOP.
This reference implementation is an example of integrating cpufreq and
PowerOP on the OMAP 1710.
