Messages in this thread |  | | | Date | Tue, 1 Feb 2011 16:53:44 +0100 | | From | Uwe Kleine-König <> | | Subject | Re: Locking in the clk API, part 2: clk_prepare/clk_unprepare |
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On Tue, Feb 01, 2011 at 03:24:58PM +0000, Russell King - ARM Linux wrote: > On Tue, Feb 01, 2011 at 04:18:46PM +0100, Uwe Kleine-König wrote: > > yeah, didn't thought about multiple consumers, so (as Jeremy suggested) > > the right thing is to sleep until CLK_BUSY is cleared. > A simpler way to write this is: > > int clk_prepare(struct clk *clk) > { > int ret = 0; > > mutex_lock(&clk->mutex); > if (clk->prepared == 0) > ret = clk->ops->prepare(clk); > if (ret == 0) > clk->prepared++; > mutex_unlock(&clk->mutex); > > return ret; > } But you cannot call this in atomic context when you know the clock is already prepared.
Best regards Uwe
-- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | http://www.pengutronix.de/ | -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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