From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757126AbaISOj3 (ORCPT ); Fri, 19 Sep 2014 10:39:29 -0400 Received: from smtprelay0235.hostedemail.com ([216.40.44.235]:51481 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753398AbaISOj1 (ORCPT ); Fri, 19 Sep 2014 10:39:27 -0400 X-Session-Marker: 6A6F6540706572636865732E636F6D X-Spam-Summary: 2,0,0,,d41d8cd98f00b204,joe@perches.com,:::::::::::::::::,RULES_HIT:41:355:379:541:599:988:989:1260:1261:1277:1311:1313:1314:1345:1359:1373:1437:1515:1516:1518:1534:1541:1593:1594:1711:1730:1747:1777:1792:2393:2559:2562:2828:3138:3139:3140:3141:3142:3352:3622:3865:3866:3867:3870:3871:3873:3874:4321:5007:7652:10004:10400:10848:11026:11232:11658:11914:12043:12050:12296:12438:12517:12519:12555:12740:13019:13069:13311:13357:21080,0,RBL:none,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:fn,MSBL:0,DNSBL:none,Custom_rules:0:0:0 X-HE-Tag: kite01_51f05e5c6a856 X-Filterd-Recvd-Size: 2225 Message-ID: <1411137561.24444.5.camel@joe-AO725> Subject: Re: [PATCH v10 5/6] rtc: max77686: Use ffs() to calculate tm_wday From: Joe Perches To: Javier Martinez Canillas Cc: Andrew Morton , Alessandro Zummo , Doug Anderson , Krzysztof Kozlowski , rtc-linux@googlegroups.com, linux-samsung-soc@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Date: Fri, 19 Sep 2014 07:39:21 -0700 In-Reply-To: <1411122377-10426-6-git-send-email-javier.martinez@collabora.co.uk> References: <1411122377-10426-1-git-send-email-javier.martinez@collabora.co.uk> <1411122377-10426-6-git-send-email-javier.martinez@collabora.co.uk> Content-Type: text/plain; charset="ISO-8859-1" X-Mailer: Evolution 3.10.4-0ubuntu2 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, 2014-09-19 at 12:26 +0200, Javier Martinez Canillas wrote: > The function max77686_rtc_calculate_wday() is used to > calculate the day of the week to be filled in struct > rtc_time but that function only calculates the number > of bits shifted. So the ffs() function can be used to > find the first bit set instead of a special function. This isn't the same logic. Perhaps you want fls. > diff --git a/drivers/rtc/rtc-max77686.c b/drivers/rtc/rtc-max77686.c [] > -static inline int max77686_rtc_calculate_wday(u8 shifted) > -{ > - int counter = -1; > - while (shifted) { > - shifted >>= 1; > - counter++; > - } > - return counter; > -} > - > static void max77686_rtc_data_to_tm(u8 *data, struct rtc_time *tm, > int rtc_24hr_mode) > { > @@ -93,7 +83,7 @@ static void max77686_rtc_data_to_tm(u8 *data, struct rtc_time *tm, > tm->tm_hour += 12; > } > > - tm->tm_wday = max77686_rtc_calculate_wday(data[RTC_WEEKDAY] & 0x7f); > + tm->tm_wday = ffs(data[RTC_WEEKDAY] & 0x7f) - 1;