From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753967AbaCZF4l (ORCPT ); Wed, 26 Mar 2014 01:56:41 -0400 Received: from mail-bn1blp0181.outbound.protection.outlook.com ([207.46.163.181]:34387 "EHLO na01-bn1-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753343AbaCZF4i (ORCPT ); Wed, 26 Mar 2014 01:56:38 -0400 From: Yao Yuan To: Marek Vasut CC: "wsa@the-dreams.de" , "mark.rutland@arm.com" , "shawn.guo@linaro.org" , "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-i2c@vger.kernel.org" Subject: RE: [PATCH v3 1/2] i2c: add DMA support for freescale i2c driver Thread-Topic: [PATCH v3 1/2] i2c: add DMA support for freescale i2c driver Thread-Index: AQHPPmRgi32QYprDqku8DK7ziduPl5ruGRqAgASY2hCAABwlAIAAJDMg Date: Wed, 26 Mar 2014 05:56:34 +0000 Message-ID: References: <1394675277-24913-1-git-send-email-yao.yuan@freescale.com> <201403230449.51515.marex@denx.de> <1e17ce716618472f9a0146c48f20b976@BL2PR03MB338.namprd03.prod.outlook.com> <201403260442.42970.marex@denx.de> In-Reply-To: <201403260442.42970.marex@denx.de> Accept-Language: zh-CN, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [123.151.195.50] x-forefront-prvs: 0162ACCC24 x-forefront-antispam-report: SFV:NSPM;SFS:(10009001)(6009001)(428001)(24454002)(377454003)(189002)(199002)(51704005)(2656002)(98676001)(81816001)(85852003)(93136001)(87266001)(90146001)(53806001)(95416001)(54316002)(94316002)(93516002)(56776001)(97336001)(76482001)(87936001)(80976001)(92566001)(54356001)(47736001)(47976001)(95666003)(47446002)(74502001)(59766001)(51856001)(4396001)(97186001)(94946001)(63696002)(20776003)(80022001)(65816001)(76576001)(81342001)(74876001)(69226001)(46102001)(74662001)(83072002)(86362001)(66066001)(79102001)(77982001)(49866001)(81542001)(33646001)(74366001)(81686001)(85306002)(83322001)(74706001)(74316001)(31966008)(50986001)(24736002);DIR:OUT;SFP:1101;SCL:1;SRVR:BL2PR03MB337;H:BL2PR03MB338.namprd03.prod.outlook.com;FPR:BEBB52EE.B4229513.89FBB544.DCD4FE69.201AE;MLV:sfv;PTR:InfoNoRecords;MX:1;A:1;LANG:en; Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 X-OriginatorOrg: freescale.com Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from base64 to 8bit by mail.home.local id s2Q5unYf027444 On Wednesday, March 26, 2014 at 11:43:27 AM, Marek Vasut wrote: > On Wednesday, March 26, 2014 at 04:08:27 AM, Yao Yuan wrote: > > [...] > > > > > + i2c_imx->use_dma = false; > > > > + } else if (i2c_imx_dma_request(i2c_imx, (dma_addr_t)phy_addr)) > { > > > > + dev_info(&pdev->dev, > > > > + "can't request dma chan, faild use dma.\n"); > > > > + i2c_imx->use_dma = false; > > > > + } else { > > > > + i2c_imx->use_dma = true; > > > > + } > > > > > > Can you not just check if i2c_imx->dma is valid pointer or NULL > pointer ? > > > Then you won't need a separate variable, for this purpose ... right ? > > > > Sorry and I think what I know is just to check whether it is NULL. > > Then for the second question, maybe there are some other ways, But I > > think it is more tidy and easier understanding for using a separate > > variable, for this purpose. > > You are just wasting space and duplicating data, unless I am wrong. > Well, Do you have a better idea? Although I think it's necessary. Best regards, Yuan Yao {.n++%ݶw{.n+{G{ayʇڙ,jfhz_(階ݢj"mG?&~iOzv^m ?I