Common clock and dvfs

[Mark Brown]

On Fri, Apr 22, 2011 at 11:15:34AM -0700, Colin Cross wrote:

> Now that we are approaching a common clock management implementation,
> I was thinking it might be the right place to put a common dvfs
> implementation as well.

I looked at this a bit when doing the S3C64xx stuff.

> frequency changes the clock first, and then calls dvfs_set_rate.  For
> a generic implementation, an SoC would provide the clock/dvfs
> framework with a list of clocks, the voltages required for each
> frequency step on the clock, and the regulator name to change.  The
> frequency/voltage tables are similar to OPP, except that OPP gets
> voltages for a device instead of a clock.  In a few odd cases (Tegra

This sounds like it assumes a 1:1 mapping between clocks and supplies
which is going to break at some point.  It should be handlable but will
add complexity.