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    SubjectRe: [PATCH 01/48] clk: at91: replace usleep() by udelay() calls
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    On Monday, June 13, 2016 5:24:09 PM CEST Alexandre Belloni wrote:
    > On 11/06/2016 at 00:30:36 +0200, Arnd Bergmann wrote :
    > > On Saturday, June 11, 2016 12:03:04 AM CEST Alexandre Belloni wrote:
    > > > From: Cyrille Pitchen <cyrille.pitchen@atmel.com>
    > > >
    > > > Fix the main and slow clock .prepare() implementations which used to call
    > > > usleep() when the scheduler wasn't ready yet.
    > > >
    > >
    > > Does this have to be called that early? It seems wasteful to always
    > > call udelay() here, when these are functions that are normally
    > > allowed to sleep.
    > >
    >
    > So I've tested it and something like that would work:
    >
    > if (system_state < SYSTEM_RUNNING)
    > udelay(osc->startup_usec);
    > else
    > usleep_range(osc->startup_usec, osc->startup_usec + 1);

    I think that's reasonable in this case.

    > But I'm afraid it would be the first driver to actually do something
    > like that (however, it is already the only driver trying to sleep).

    We have a lot of drivers that call potentially sleeping function from
    the .prepare callback, e.g. when they go to an i2c controller.

    Arnd

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