Messages in this thread | | | Date | Mon, 14 Jun 2010 11:43:10 +0200 | From | Uwe Kleine-König <> | Subject | Re: [RFC,PATCH 1/2] Add a common struct clk |
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On Mon, Jun 14, 2010 at 11:30:08AM +0200, Lothar Waßmann wrote: > Benjamin Herrenschmidt writes: > > On Mon, 2010-06-14 at 08:39 +0200, Lothar Waßmann wrote: > > > All implementations so far use spin_lock_irq_save()! > > > > Nothing prevents your implementation to be a tad smarter. > > > I vote for consistency, so that device drivers can be kept arch > independent instead of having to care about implentation details of > each arch. Back when I implemented clock support for ns9xxx (unfortunately not in mainline) I tried with a spinlock first and later switched to a mutex. IIRC the reason was that on ns9215 enabling the rtc clock took long (don't remember a number) and successfull enabling was signaled by an irq. So I would have had to implement irq polling in the clock code.
I think you can find different examples that make both possiblities bad. All in all I think that a sleeping clock implementation is preferable as it improves (general) latencies.
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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