From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751643AbbARMBa (ORCPT ); Sun, 18 Jan 2015 07:01:30 -0500 Received: from www.osadl.org ([62.245.132.105]:36497 "EHLO www.osadl.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751045AbbARMB3 (ORCPT ); Sun, 18 Jan 2015 07:01:29 -0500 From: Nicholas Mc Guire To: Ian Abbott Cc: H Hartley Sweeten , Greg Kroah-Hartman , devel@driverdev.osuosl.org, linux-kernel@vger.kernel.org, Nicholas Mc Guire Subject: [PATCH RFC] comedi: rtd520: if condition with no effect - if identical to else Date: Sun, 18 Jan 2015 12:53:24 +0100 Message-Id: <1421582004-2398-1-git-send-email-der.herr@hofr.at> X-Mailer: git-send-email 1.7.10.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The if and the else branch code are identical - so the condition has no effect on the effective code - this patch removes the condition and the duplicated code. Signed-off-by: Nicholas Mc Guire --- Patch is against 3.19.0-rc4 -next-20150116 This patch was only compile tested with x86_64_defconfig + CONFIG_STAGING=y CONFIG_COMEDI=m, CONFIG_COMEDI_PCI_DRIVERS=m, CONFIG_COMEDI_RTD520=m commit c5930d66 (staging: comedi: rtd520: use the comedi_device 'mmio' member) introduced the current code, the probably bug was though present before this commit: if (devpriv->xfer_count > 0) /* transfer every N samples */ writew(IRQM_ADC_ABOUT_CNT, dev->mmio + LAS0_IT); else /* 1/2 FIFO transfers */ writew(IRQM_ADC_ABOUT_CNT, dev->mmio + LAS0_IT); as the if and else branch are identical but the comments indicate that they are serving different purposes this looks like a bug. The code has though been in use in this form for more than 2 years - so maybe the condition is simply unnecessary. In any case this needs a review by someone who knows the details of the driver - the below patch is only cleaning up the current situation and may thus be wrong. ...and how did this pass multiple modifications and reviews ?... drivers/staging/comedi/drivers/rtd520.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/drivers/staging/comedi/drivers/rtd520.c b/drivers/staging/comedi/drivers/rtd520.c index 06ae436..3ccdade 100644 --- a/drivers/staging/comedi/drivers/rtd520.c +++ b/drivers/staging/comedi/drivers/rtd520.c @@ -1012,10 +1012,8 @@ static int rtd_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s) readw(dev->mmio + LAS0_CLEAR); /* TODO: allow multiple interrupt sources */ - if (devpriv->xfer_count > 0) /* transfer every N samples */ - writew(IRQM_ADC_ABOUT_CNT, dev->mmio + LAS0_IT); - else /* 1/2 FIFO transfers */ - writew(IRQM_ADC_ABOUT_CNT, dev->mmio + LAS0_IT); + /* transfer every N samples */ + writew(IRQM_ADC_ABOUT_CNT, dev->mmio + LAS0_IT); /* BUG: start_src is ASSUMED to be TRIG_NOW */ /* BUG? it seems like things are running before the "start" */ -- 1.7.10.4