From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965303Ab3DIJ3M (ORCPT ); Tue, 9 Apr 2013 05:29:12 -0400 Received: from sauhun.de ([89.238.76.85]:48330 "EHLO pokefinder.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S936418Ab3DIJ27 (ORCPT ); Tue, 9 Apr 2013 05:28:59 -0400 Date: Tue, 9 Apr 2013 11:28:57 +0200 From: Wolfram Sang To: Mika Westerberg Cc: linux-kernel@vger.kernel.org, linux-i2c@vger.kernel.org, ben-linux@fluff.org, Jean Delvare , Andy Shevchenko , Christian Ruppert Subject: Re: [5/7] i2c-designware: enable/disable the controller properly Message-ID: <20130409092857.GE3624@the-dreams.de> References: <1363867800-23861-5-git-send-email-mika.westerberg@linux.intel.com> <20130409090914.GD28509@the-dreams.de> <20130409092836.GG21818@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130409092836.GG21818@intel.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Apr 09, 2013 at 12:28:36PM +0300, Mika Westerberg wrote: > On Tue, Apr 09, 2013 at 11:09:14AM +0200, Wolfram Sang wrote: > > > > > +static void __i2c_dw_enable(struct dw_i2c_dev *dev, bool enable) > > > +{ > > > + int timeout = 100; > > > + > > > + do { > > > + dw_writel(dev, enable, DW_IC_ENABLE); > > > + if ((dw_readl(dev, DW_IC_ENABLE_STATUS) & 1) == enable) > > > + return; > > > + > > > + usleep_range(25, 250); > > > > This would wait 25ms max. Is there a timeout value specified in the docs? > > The datasheet says something like: > > 1. Define a timer interval (t_i2c_poll) equal 10 times the highest > signaling period. For 400kHz this is 25us. > > 2. Define max timeout parameter, MAX_T_POLL_COUNT, such that if any > repeated operation exeeds this maximum, an error is reported. > > In this case I have: > > t_i2c_poll = 25 (to 250 us) > MAX_T_POLL_COUNT = 100 Maybe worth a comment? Other than that, the series looks fine to me.