Re: [PATCH E 08/14] OMAP clock: move rate recalc, propagation codeup to plat-omap/clock.c

From: Paul Walmsley
Date: Tue Feb 03 2009 - 03:42:21 EST


Hello Russell,

On Sat, 31 Jan 2009, Russell King - ARM Linux wrote:

> On Fri, Jan 30, 2009 at 08:23:49AM -0600, Woodruff, Richard wrote:
> >
> > > There's one bug that your version highlights in mine - the virtual mpu
> > > clock in omap1 touches the DPLL and repropagates that rate. I've
> > > removed that repropagation, so that needs fixing.
> > >
> > > However, this raises a question: why is the virtual mpu clock touching
> > > some other part of the clock tree. I wonder whether this should be
> > > handled a different way, though the first thing that needs answering is
> > > why we have this alias for 'arm_ck' ?
> >
> > At one point in time the virtual clock allowed control for a set of clocks
> > with some dependencies. The mpu alias provided a convenient control point.
>
> >From what I can see (checking both mainline and Tony's tree), this mpu
> alias (virtual_ck_mpu) is not used on OMAP1, which seems to suggest
> that this quirk has become redundant. If it is redundant, it should
> be removed.
>
> If there is some code somewhere to use it, this quirk should live with
> the user of the quirk until such time that the user becomes ready to be
> merged.

I don't think there's any reason for virtual_ck_mpu or virt_prcm_set to
have a parent clock listed.

At some point this year, those virtual OPP clocks will be removed from the
clock tree and implemented in a different manner.

If you like, I will send a patch for removal of virtual_ck_mpu from OMAP1,
although my suspicion is that OMAP1 is just missing a CPUFreq driver to
use that OPP clock.


- Paul
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