From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758915Ab2BJJUc (ORCPT ); Fri, 10 Feb 2012 04:20:32 -0500 Received: from hqemgate04.nvidia.com ([216.228.121.35]:15177 "EHLO hqemgate04.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758379Ab2BJJU3 convert rfc822-to-8bit (ORCPT ); Fri, 10 Feb 2012 04:20:29 -0500 X-PGP-Universal: processed; by hqnvupgp07.nvidia.com on Fri, 10 Feb 2012 01:20:26 -0800 From: Alok Chauhan To: Alok Chauhan , Ben Dooks CC: "khali@linux-fr.org" , "ben-linux@fluff.org" , Stephen Warren , "olof@lixom.net" , "bones@secretlab.ca" , "paul.gortmaker@windriver.com" , "dgreid@google.com" , Laxman Dewangan , "linux-tegra@vger.kernel.org" , "linux-i2c@vger.kernel.org" , "linux-kernel@vger.kernel.org" Date: Fri, 10 Feb 2012 14:50:22 +0530 Subject: RE: [PATCH v2] i2c: tegra: Add delay before reset the controller Thread-Topic: [PATCH v2] i2c: tegra: Add delay before reset the controller Thread-Index: AczMjswFlL9LJKsmQoCUsX6RILKtcACvas5ABiHcoQA= Message-ID: <7A0BFCFE3DA5CD47B0FB7984326F201A13689D36EE@BGMAIL01.nvidia.com> References: <1324898081-10308-1-git-send-email-alokc@nvidia.com> <20120106161803.GQ19115@trinity.fluff.org> <7A0BFCFE3DA5CD47B0FB7984326F201A134F2CD4F1@BGMAIL01.nvidia.com> In-Reply-To: <7A0BFCFE3DA5CD47B0FB7984326F201A134F2CD4F1@BGMAIL01.nvidia.com> Accept-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: acceptlanguage: en-US MIME-Version: 1.0 Content-Language: en-US Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > On Mon, Dec 26, 2011 at 04:44:41PM +0530, Alok Chauhan wrote: >> > + /* > + * In NACK error condition resetting of I2C controller happens > + * before STOP condition is properly completed by I2C controller, > + * so wait for 2 clock cycle to complete STOP condition. > + */ > + if (i2c_dev->msg_err == I2C_ERR_NO_ACK) > + udelay(DIV_ROUND_UP(2 * 1000000, i2c_dev->bus_clk_rate)); > + >Is a delay here good, would it be better to sleep so that some other process can gain cpu time? >>We mostly used 100 khz i2c clock frequency and delay in that case will be 20 usec. Would it be ok to sleep for such a smaller time? Won't it increase any other overhead? Please let me know if sleep is better option here instead of waiting. Thanks Alok -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html