From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Brownell Subject: Re: [PATCH] i2c: i2c-omap: Fix standard and fast mode prescalers Date: Fri, 14 Nov 2008 11:45:30 -0800 Message-ID: <200811141145.30171.david-b@pacbell.net> References: <12266521173159-git-send-email-ext-eero.nurkkala@nokia.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from smtp127.sbc.mail.sp1.yahoo.com ([69.147.65.186]:27769 "HELO smtp127.sbc.mail.sp1.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1752864AbYKNTpc (ORCPT ); Fri, 14 Nov 2008 14:45:32 -0500 In-Reply-To: <12266521173159-git-send-email-ext-eero.nurkkala@nokia.com> Content-Disposition: inline Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: ext-eero.nurkkala@nokia.com Cc: linux-omap@vger.kernel.org On Friday 14 November 2008, ext-eero.nurkkala@nokia.com wrote: > The prescalers for 100 kHz and 400 kHz mode > are wrong. The internal clock is the fclock > divided by the prescaler. The PSC is an 8 bit > field in omap3430. Moreover, the scll and > sclh values should be adjusted properly. > Having the correct prescaler is important in > the process of getting a finite i2c clock. In > addition, the prescaler is used in the process > of activating the correct noise filter and thus, > lets more error resilient i2c communications. Should this fix the bug causing the need for that recent ZOOM patch slowing down twl4030 communication to 400 MHz? And should it let at least some boards talk to their TWL chips at 3.4 MBit/sec (top speed for standard highspeed I2C) instead of 2.6 Mbit/sec (pokey slow)? I've always wondered why all the boards configured those links to be seemingly slower than allowed ... - Dave