From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E1F51C43382 for ; Thu, 27 Sep 2018 17:41:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 90074215F0 for ; Thu, 27 Sep 2018 17:41:18 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 90074215F0 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728451AbeI1AAi (ORCPT ); Thu, 27 Sep 2018 20:00:38 -0400 Received: from mga12.intel.com ([192.55.52.136]:4785 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727320AbeI1AAi (ORCPT ); Thu, 27 Sep 2018 20:00:38 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by fmsmga106.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 27 Sep 2018 10:41:16 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.54,311,1534834800"; d="scan'208";a="95465871" Received: from yoojae-mobl1.amr.corp.intel.com (HELO [10.7.153.151]) ([10.7.153.151]) by orsmga002.jf.intel.com with ESMTP; 27 Sep 2018 10:41:16 -0700 Subject: Re: [PATCH i2c-next v3 2/3] i2c: aspeed: Add 'aspeed,timeout' DT property reading code To: Joel Stanley Cc: Brendan Higgins , Wolfram Sang , Benjamin Herrenschmidt , Rob Herring , Mark Rutland , Andrew Jeffery , linux-i2c@vger.kernel.org, OpenBMC Maillist , devicetree , Linux ARM , linux-aspeed@lists.ozlabs.org, Linux Kernel Mailing List , jarkko.nikula@linux.intel.com, James Feist , Vernon Mauery References: <20180926215842.23125-1-jae.hyun.yoo@linux.intel.com> <20180926215842.23125-3-jae.hyun.yoo@linux.intel.com> From: Jae Hyun Yoo Message-ID: <37ae7a11-44b6-88e5-0f4d-c97c70334ad4@linux.intel.com> Date: Thu, 27 Sep 2018 10:41:16 -0700 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Joel, On 9/26/2018 8:11 PM, Joel Stanley wrote: > On Thu, 27 Sep 2018 at 01:58, Jae Hyun Yoo wrote: >> >> +/* Timeout */ >> +#define ASPEED_I2C_BUS_TIMEOUT_US_DEFAULT (5 * 1000 * 1000) > > The 5 seconds time out is way too long. On a system that doesn't have > functional i2c, this holds up boot for a long time as most i2c client > drivers try to initialise their device and fail. I realise you're not > changing the value, but we should pick a better default. 1 second? > Half a second? > I agree with you. We could probably use 1 second as default which can cover the most of general cases. If so, we don't need to make the default setting in this driver because i2c-core-base will default adap->timeout to 1 second if the value is 0 when a driver registers an adapter. Will fix this code. >> >> + ret = of_property_read_u32(pdev->dev.of_node, "aspeed,timeout", >> + &timeout_us); > > Can we make this binding generic? It's not specific to aspeed's > hardware. Getting the value could even part of the i2c core. > > I read the previous thread with Wolfram. I think this would still fit > with what Wolfram suggested, but please forgive my jetlagged brain if > I've missed something. > It followed the way of the existing i2c-mpc driver uses 'fsl,timeout' for the same purpose. Though, I also want to make it as a generic as you suggested like 'timeout' in milliseconds unit, not in microseconds unit. If making it a generic property is acceptable, I'll fix it too. Wolfram, can you please share your thought on it? Thanks, Jae