linux-kernel - Re: [PATCH 1/3] backlight: da9052: Use usleep_range() instead of msleep() for small sleeps

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Message-ID: <20120807162821.GA14711@sirena.org.uk>
Date:	Tue, 7 Aug 2012 17:28:22 +0100
From:	Mark Brown <broonie@...nsource.wolfsonmicro.com>
To:	Jingoo Han <jg1.han@...sung.com>
Cc:	'Sachin Kamat' <sachin.kamat@...aro.org>,
	'Andrew Morton' <akpm@...ux-foundation.org>,
	'LKML' <linux-kernel@...r.kernel.org>,
	'Richard Purdie' <rpurdie@...ys.net>,
	'Ashish Jangam' <ashish.jangam@...tcummins.com>
Subject: Re: [PATCH 1/3] backlight: da9052: Use usleep_range() instead of
 msleep() for small sleeps

On Mon, Aug 06, 2012 at 01:59:38PM +0900, Jingoo Han wrote:
> On Monday, August 06, 2012 1:48 PM Sachin Kamat wrote:

> > > +       usleep_range(10000, 11000);

> > Can't we just use usleep(10000) instead?

> usleep() is not available.
> For more details, refer to Documentation/timers/timers-howto.txt.

Given how common this pattern is is it not more sensible to just
provide usleep() even if just as an inline that's something like

   void usleep(unsigned long t)
   {
   	usleep_range(t, t + (t / 10));
   }

since the usleep_range() isn't ideal for clarity (and usually the upper
bound isn't a particular concern for the driver, it just wants the usual
"delay for at least x" semantics).
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