Re: machdep.frequency.current handling incomplete ?

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

On Sun, Jul 20, 2014 at 10:36:41PM +0200, Radoslaw Kujawa wrote:
> > thanks for the pointer, indeed I did find the post, which pointed me to the
> > right part of the device tree.
> > Now the problem is that looking for device trees I found conflicting infos.
> > The dts supplied with linux 3.5 starts from 275 to only 720 Mhz.
> > Can we run as low as 275Mhz ?
> > I found other dts fragments with entries for 1Ghz, but they don't have the
> > same voltage for the same frequencies.
> > And we are using frequencies that are not in these device trees.
> 
> Obviously, entries up to 720MHz must be for original BeagleBone, while up to 
> 1GHz must be for BeagleBone Black.

I didn't remember that the BeagleBone couldn't run at 1Ghz.
Interestingly it did run at 900Mhz when not too heavily loaded.
This is going to make things a bit harder then, we'll need 2 tables and a
way to know which CPU we have.

> 
> > So now I'm trying to find some official documentation which would
> > give the voltage for a given frequency ...
> 
> Search for information about OPP in the official OMAP3530 datasheet. Each OPP 
> (operating performance point) level corresponds to a different DPLL clock 
> speed setting. There?s also a table with recommended voltages for each OPP in 
> the same datasheet.
> 
> http://www.ti.com/product/AM3358/datasheet/specifications#SPRS717-32
> 
> Note the different settings for ZCZ Package with Device Revision Code Blank 
> (i.e. BB) and ZCZ Package with Device Revision Code A (i.e. BBB). 

yes, so this means 2 tables ...
 
> So, yeah, we should extend the tps65217pmic(4) to allow messing with voltage 
> settings after all.

I'm working on it.

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
--