From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752809Ab2GRHzi (ORCPT ); Wed, 18 Jul 2012 03:55:38 -0400 Received: from slimlogic.co.uk ([89.16.172.20]:34254 "EHLO slimlogic.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750999Ab2GRHzc (ORCPT ); Wed, 18 Jul 2012 03:55:32 -0400 Message-ID: <50066BF2.7050507@slimlogic.co.uk> Date: Wed, 18 Jul 2012 08:55:30 +0100 From: Graeme Gregory User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:14.0) Gecko/20120714 Thunderbird/14.0 MIME-Version: 1.0 To: Axel Lin CC: Mark Brown , linux-kernel@vger.kernel.org, Liam Girdwood Subject: Re: [PATCH] regulator: palmas: Fix calculating selector in palmas_map_voltage_ldo References: <1342582211.12515.2.camel@phoenix> In-Reply-To: <1342582211.12515.2.camel@phoenix> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 18/07/12 04:30, Axel Lin wrote: > This patch fixes below issues when choosing selector: > > 1. Current code returns negative selector if min_uV < 900000 which is wrong. > For example, it is possible to satisfy the request with selector = 1 if > the requested min_uV is 850000. Isnt this defending against bugs in the regulator core? I am normally against repeating the same checks at multiple levels in a stack. > 2. Current code may select a voltage lower than requested min_uV. > For example, if the requested min_uV is 945000, current code chooses > selector = 1 which is lower than requested min_uV. > DIV_ROUND_UP to avoid this case. > > Signed-off-by: Axel Lin > --- > drivers/regulator/palmas-regulator.c | 9 ++++++--- > 1 file changed, 6 insertions(+), 3 deletions(-) > > diff --git a/drivers/regulator/palmas-regulator.c b/drivers/regulator/palmas-regulator.c > index 17d19fb..0fcf355 100644 > --- a/drivers/regulator/palmas-regulator.c > +++ b/drivers/regulator/palmas-regulator.c > @@ -486,9 +486,12 @@ static int palmas_map_voltage_ldo(struct regulator_dev *rdev, > { > int ret, voltage; > > - ret = ((min_uV - 900000) / 50000) + 1; > - if (ret < 0) > - return ret; > + if (min_uV == 0) > + return 0; > + > + if (min_uV < 900000) > + min_uV = 900000; > + ret = DIV_ROUND_UP(min_uV - 900000, 50000) + 1; > > /* Map back into a voltage to verify we're still in bounds */ > voltage = palmas_list_voltage_ldo(rdev, ret);