From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757145Ab3ANRR3 (ORCPT ); Mon, 14 Jan 2013 12:17:29 -0500 Received: from perches-mx.perches.com ([206.117.179.246]:39612 "EHLO labridge.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1756606Ab3ANRR2 (ORCPT ); Mon, 14 Jan 2013 12:17:28 -0500 Message-ID: <1358183857.19400.13.camel@joe-AO722> Subject: Re: [PATCH 04/18] power: ab8500_fg: Replace msleep() with usleep_range() for greater accuracy From: Joe Perches To: Lee Jones Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, arnd@arndb.de, linus.walleij@stericsson.com, cbouatmailru@gmail.com, Jonas Aaberg Date: Mon, 14 Jan 2013 09:17:37 -0800 In-Reply-To: <1357909986-9262-5-git-send-email-lee.jones@linaro.org> References: <1357909986-9262-1-git-send-email-lee.jones@linaro.org> <1357909986-9262-5-git-send-email-lee.jones@linaro.org> Content-Type: text/plain; charset="ISO-8859-1" X-Mailer: Evolution 3.6.0-0ubuntu3 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2013-01-11 at 13:12 +0000, Lee Jones wrote: > Doing so provides a greater degree of accuracy when dealing with > time-frames between 1us and 20ms. msleep() is only accurate for > wake-ups greater than 20ms. [] > diff --git a/drivers/power/ab8500_fg.c b/drivers/power/ab8500_fg.c [] > @@ -956,7 +956,7 @@ static int ab8500_fg_load_comp_volt_to_capacity(struct ab8500_fg *di) > do { > vbat += ab8500_fg_bat_voltage(di); > i++; > - msleep(5); > + usleep_range(5000, 5001); If you're going to give a range that small you might as well use usleep instead. Otherwise, add some tolerance to allow any other coalesced wakeup to occur.