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    SubjectRe: [PATCH E 08/14] OMAP clock: move rate recalc, propagation code up to plat-omap/clock.c
    Hi 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.

    It was probably an OMAP1 implementation of OPPs, similar to virt_prcm_set
    on OMAP2. Looks like the tree is missing a CPUFreq driver that uses it.
    Cc'ing Tuukka in case he recalls.

    One fix that might solve your particular problem would be to remove the
    parent clock pointer from virtual_ck_mpu. Neither virtual_ck_mpu or
    virt_prcm_set should need it.

    - Paul

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