Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755865Ab3DZNcw (ORCPT ); Fri, 26 Apr 2013 09:32:52 -0400 Received: from hedwig.cmf.nrl.navy.mil ([134.207.12.162]:38346 "EHLO hedwig.cmf.nrl.navy.mil" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754218Ab3DZNcu (ORCPT ); Fri, 26 Apr 2013 09:32:50 -0400 X-Greylist: delayed 835 seconds by postgrey-1.27 at vger.kernel.org; Fri, 26 Apr 2013 09:32:50 EDT Date: Fri, 26 Apr 2013 09:12:20 -0400 From: chas williams - CONTRACTOR To: "David Laight" Cc: "Arnd Bergmann" , , , , Subject: Re: [PATCH 05/21] atm: he: use mdelay instead of large udelay constants Message-ID: <20130426091220.468cf59e@thirdoffive.cmf.nrl.navy.mil> In-Reply-To: References: <1366910944-3033663-1-git-send-email-arnd@arndb.de> <1366910944-3033663-6-git-send-email-arnd@arndb.de> X-Mailer: Claws Mail 3.9.0 (GTK+ 2.24.8; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-NRLCMF-Spam-Score: () hits=0 X-NRLCMF-Virus-Scanned: No virus found X-NRLCMF-Languages: en Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1105 Lines: 28 On Fri, 26 Apr 2013 09:21:59 +0100 "David Laight" wrote: > > ARM cannot handle udelay for more than 2 miliseconds, so we > > should use mdelay instead for those. > ... > > @@ -1055,7 +1055,7 @@ static int he_start(struct atm_dev *dev) > > he_writel(he_dev, 0x0, RESET_CNTL); > > he_writel(he_dev, 0xff, RESET_CNTL); > > > > - udelay(16*1000); /* 16 ms */ > > + mdelay(16); /* 16 ms */ > > status = he_readl(he_dev, RESET_CNTL); > > 16ms seems a long time to spin. > I'd have thought a sleep would be more appropriate. > Since this looks like timing a hardware reset pulse > it can't matter if it is somewhat longer. Yes, I wrote this bit some time ago when I was less wise. The programmer's guide doesn't say how long to sleep, so the value isn't critical. It just has to be "long enough". An msleep() would be fine here. -- 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/