From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BD690C43382 for ; Wed, 26 Sep 2018 06:47:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 556BB2089D for ; Wed, 26 Sep 2018 06:47:59 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 556BB2089D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=pengutronix.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727241AbeIZM7U (ORCPT ); Wed, 26 Sep 2018 08:59:20 -0400 Received: from metis.ext.pengutronix.de ([85.220.165.71]:48591 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726368AbeIZM7U (ORCPT ); Wed, 26 Sep 2018 08:59:20 -0400 Received: from dude.hi.pengutronix.de ([2001:67c:670:100:1d::7]) by metis.ext.pengutronix.de with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1g53c2-0002EY-TX; Wed, 26 Sep 2018 08:47:54 +0200 Received: from sha by dude.hi.pengutronix.de with local (Exim 4.91) (envelope-from ) id 1g53c0-0000JJ-JO; Wed, 26 Sep 2018 08:47:52 +0200 Date: Wed, 26 Sep 2018 08:47:52 +0200 From: Sascha Hauer To: Fabio Estevam Cc: Abel Vesa , Lucas Stach , Sascha Hauer , Dong Aisheng , Fabio Estevam , Anson Huang , Andrey Smirnov , Rob Herring , Stephen Boyd , Michael Turquette , open list , "open list:COMMON CLK FRAMEWORK" , Abel Vesa , NXP Linux Team , Shawn Guo , "moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE" Subject: Re: [PATCH v9 4/5] clk: imx: add imx composite clock Message-ID: <20180926064752.GM4097@pengutronix.de> References: <1537785597-26499-1-git-send-email-abel.vesa@nxp.com> <1537785597-26499-5-git-send-email-abel.vesa@nxp.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Sent-From: Pengutronix Hildesheim X-URL: http://www.pengutronix.de/ X-IRC: #ptxdist @freenode X-Accept-Language: de,en X-Accept-Content-Type: text/plain X-Uptime: 08:37:07 up 131 days, 18:17, 163 users, load average: 21.66, 19.09, 11.16 User-Agent: Mutt/1.10.0 (2018-05-17) X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::7 X-SA-Exim-Mail-From: sha@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Sep 25, 2018 at 01:42:12PM -0300, Fabio Estevam wrote: > Hi Abel, > > On Mon, Sep 24, 2018 at 7:39 AM, Abel Vesa wrote: > > > +static long imx_clk_composite_divider_round_rate(struct clk_hw *hw, > > + unsigned long rate, > > + unsigned long *prate) > > +{ > > + int prediv_value; > > + int div_value; > > + > > + imx_clk_composite_compute_dividers(rate, *prate, > > + &prediv_value, &div_value); > > + > > + rate = DIV_ROUND_UP_ULL((u64)*prate, prediv_value); > > You assing a value to 'rate' here. > > > + rate = DIV_ROUND_UP_ULL((u64)rate, div_value); > > And then overwrite it immediately after. It's: rate = *prate / prediv_value; rate = rate / div_value; To me this looks correct. However, For an unsigned long type we have DIV_ROUND_UP() with which we do not need any casting. For 64bit code unsigned long is 64bit anyway which makes the cast a no-op and for 32bit code there's also no point in exanding the initial 32bit value to 64bit. Sascha -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |