From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756697Ab3AOSay (ORCPT ); Tue, 15 Jan 2013 13:30:54 -0500 Received: from perches-mx.perches.com ([206.117.179.246]:42968 "EHLO labridge.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750963Ab3AOSax (ORCPT ); Tue, 15 Jan 2013 13:30:53 -0500 Message-ID: <1358274665.2597.11.camel@joe-AO722> Subject: Re: [PATCH 1/1] clk-divider: fix is_power_of_two() From: Joe Perches To: James Hogan Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Mike Turquette Date: Tue, 15 Jan 2013 10:31:05 -0800 In-Reply-To: <1358245685-4392-1-git-send-email-james.hogan@imgtec.com> References: <1358245685-4392-1-git-send-email-james.hogan@imgtec.com> 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 Tue, 2013-01-15 at 10:28 +0000, James Hogan wrote: > The macro is_power_of_two() in clk-divider.c was defined as !(i & ~i) > which is always true. Correct it to !(i & (i - 1)). [] > diff --git a/drivers/clk/clk-divider.c b/drivers/clk/clk-divider.c [] > @@ -29,8 +29,8 @@ [] > -#define div_mask(d) ((1 << (d->width)) - 1) > -#define is_power_of_two(i) !(i & ~i) > +#define div_mask(d) ((1 << ((d)->width)) - 1) > +#define is_power_of_two(i) (!((i) & ((i) - 1))) Use is_power_of_2 in log2.h instead?