Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754654Ab2KZNqd (ORCPT ); Mon, 26 Nov 2012 08:46:33 -0500 Received: from moutng.kundenserver.de ([212.227.17.8]:52999 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753123Ab2KZNqc (ORCPT ); Mon, 26 Nov 2012 08:46:32 -0500 Date: Mon, 26 Nov 2012 14:46:25 +0100 (CET) From: Guennadi Liakhovetski X-X-Sender: lyakh@axis700.grange To: Axel Lin cc: Mark Brown , Liam Girdwood , linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/2] regulator: as3711: Fix the logic in as3711_sel_check In-Reply-To: <1353689602.3260.7.camel@phoenix> Message-ID: References: <1353689452.3260.4.camel@phoenix> <1353689602.3260.7.camel@phoenix> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Provags-ID: V02:K0:2eW+JvVOAPf4LxiaxTo5Jt3atjEG+ho0dbakuJXctFl w6AUPbmg4aL8hSm9qwxpAe54DZ61KAZyOE5PljR2xmYdqwqhi5 A1RQwNhU1xl0/upshyF8bijLVMRydhtmTEh+2RP9VWy3whZS39 KOxsFe1XPQDx+CSCE/+g33htCKZ9650f1ZbODtPN8k2HXyOnMX JCI/3ZNHiPqLxpwO0a6yeLrbrtw1ESbWQlXoznE2/ZS9FyEB19 BOhJEnS9+igIE2YOqkMYdaTnBG84I/8CpRUFoWOP0lmm7JzKSQ kyLztBmtbm/sUJa/gpr8hFE9XXsMnHpfmDkEOUKRmm6JHMhvfH eKVcVy/sR3iAxp/XGjWQrQ4XG8S415piCCNSJ/48GTHe34BLN9 wuy3Oc9B/87IA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2362 Lines: 79 On Sat, 24 Nov 2012, Axel Lin wrote: > Below equation means the "voltage" is the "smallest" voltage within specific > range. > > ret = DIV_ROUND_UP(min - bottom) / step; > voltage = ret * step + bottom; > > If we do try 1 down when (voltage > max), new voltage is then less than min > voltage. Which means the new voltage is not in the requested voltage range. > > This patch also includes below cleanups: > - Use DIV_ROUND_UP > - rename variable 'ret' to 'sel' for better readability because as3711_sel_check > returns the selector. > > Signed-off-by: Axel Lin Acked-by: Guennadi Liakhovetski Thanks Guennadi > --- > drivers/regulator/as3711-regulator.c | 23 ++++++++--------------- > 1 file changed, 8 insertions(+), 15 deletions(-) > > diff --git a/drivers/regulator/as3711-regulator.c b/drivers/regulator/as3711-regulator.c > index 5e813b9..2f1341d 100644 > --- a/drivers/regulator/as3711-regulator.c > +++ b/drivers/regulator/as3711-regulator.c > @@ -93,24 +93,17 @@ static int as3711_bound_check(struct regulator_dev *rdev, > > static int as3711_sel_check(int min, int max, int bottom, int step) > { > - int ret, voltage; > + int sel, voltage; > > /* Round up min, when dividing: keeps us within the range */ > - ret = (min - bottom + step - 1) / step; > - voltage = ret * step + bottom; > + sel = DIV_ROUND_UP(min - bottom, step); > + voltage = sel * step + bottom; > pr_debug("%s(): select %d..%d in %d+N*%d: %d\n", __func__, > - min, max, bottom, step, ret); > - if (voltage > max) { > - /* > - * Try 1 down. It will take us below min, but as long we stay > - * above bottom, we're fine. > - */ > - ret--; > - voltage = ret * step + bottom; > - if (voltage < bottom) > - return -EINVAL; > - } > - return ret; > + min, max, bottom, step, sel); > + if (voltage > max) > + return -EINVAL; > + > + return sel; > } > > static int as3711_map_voltage_sd(struct regulator_dev *rdev, > -- > 1.7.9.5 > > > --- Guennadi Liakhovetski, Ph.D. Freelance Open-Source Software Developer http://www.open-technology.de/ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/