[PATCHv5 02/14] arm: omap: voltage: renamed vp_vddmin and vp_vddmax fields

Tero Kristo t-kristo at ti.com
Tue Feb 21 10:32:50 EST 2012


On Tue, 2012-02-21 at 14:53 +0000, Russell King - ARM Linux wrote:
> On Tue, Feb 21, 2012 at 08:40:22AM -0600, Menon, Nishanth wrote:
> > On Tue, Feb 21, 2012 at 08:04, Tero Kristo <t-kristo at ti.com> wrote:
> > > These are now called vddmin and vddmax, as these fields will be used
> > > globally for selecting voltage ranges for a pmic channel, and not
> > > only for voltage processor.
> > 
> > NAK. I think we need to setup voltage for SoC limits as well. the
> > programmed voltage to the VP register should be:
> > VP->vlimito->min = MAX(soc->vdd_min, pmic->vdd_min)
> > VP->vlimito->max = MIN(soc->vdd_max, pmic->vdd_max)
> > 

This kind of code is actually introduced in patch #7 of this set. VP
part of the code calculates the voltage processor vlimitto values in
omap_vp_init. VC limits are handled in omap_vc_init_channel /
omap_vc_calc_vsel.

> > else you could be running the SoC beyond design voltage potentially
> > damaging the device.
> 
> And if you're doing that kind of thing, you must also check that
> the resulting min and max are sane.  In other words, the minimum is
> less than the maximum.
> 
> Sure, it's something that should never happen (because it would be a
> design error) but if it did happen...

This could be added yes, current code assumes the limits themselves are
at least somewhat sane, doesn't hurt to add a kern dump for this case I
think as it sounds rather fatal.

-Tero





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