From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tony Lindgren Subject: Re: [PATCH] I2C: Fix twl4030 timeouts on omap3430 Date: Tue, 1 Apr 2008 15:43:56 +0300 Message-ID: <20080401124354.GS26502@atomide.com> References: <20080328084139.GJ24896@atomide.com> <20080331104332.GH26502@atomide.com> <20080331143011.GO26502@atomide.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mho-01-bos.mailhop.org ([63.208.196.178]:49297 "EHLO mho-01-bos.mailhop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754497AbYDAMn6 (ORCPT ); Tue, 1 Apr 2008 08:43:58 -0400 Received: from muru.com ([72.249.23.125] helo=localhost.localdomain) by mho-01-bos.mailhop.org with esmtpa (Exim 4.68) (envelope-from ) id 1JgfqH-000PTG-Ae for linux-omap@vger.kernel.org; Tue, 01 Apr 2008 12:43:57 +0000 Content-Disposition: inline In-Reply-To: <20080331143011.GO26502@atomide.com> Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: linux-omap@vger.kernel.org * Tony Lindgren [080331 17:30]: > * Tony Lindgren [080331 13:43]: > > * Tony Lindgren [080328 10:41]: > > > Hi all, > > > > > > This helps with the annoying I2C timeouts. Does anybody have an idea > > > why the twl4030 chip does not like doing multiple transfers in a row? > > > > > > To me the only difference seems to be that clocks are idled between > > > writing the twl4030 register and reading the register value. > > > > I'll push this today with a REVISIT comment added. > > Looks like this kills twl4030 interrupts, so I've reverted it. After looking into this problem a bit more, looks like twl4030 reads to anything in "POWER ID" (modules 0x10 and higher) will hang twl4030 eventually and I2C controller gets stuck in mode where STP never clears. Repeated reads to "USB ID", "AUD ID" or "AUX ID" will not hang twl4030. Tony