From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jarkko Nikula Subject: Re: [PATCH v2 0/2] i2c:dw: Add APM X-Gene ACPI I2C device support Date: Wed, 16 Dec 2015 14:53:02 +0200 Message-ID: <56715EAE.4080006@linux.intel.com> References: <1449782357-22982-1-git-send-email-lho@apm.com> <566F6485.2000508@amd.com> <20151215132721.GJ1762@lahna.fi.intel.com> <56702923.9010305@amd.com> <20151215145953.GK1762@lahna.fi.intel.com> <20151216090454.GL1762@lahna.fi.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mga14.intel.com ([192.55.52.115]:56950 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752922AbbLPMzP (ORCPT ); Wed, 16 Dec 2015 07:55:15 -0500 In-Reply-To: <20151216090454.GL1762@lahna.fi.intel.com> Sender: linux-i2c-owner@vger.kernel.org List-Id: linux-i2c@vger.kernel.org To: Mika Westerberg , Loc Ho Cc: Suravee Suthikulpanit , wsa@the-dreams.de, Ken Xue , Jeff.Wu@amd.com, rjw@rjwysocki.net, Len Brown , linux-i2c@vger.kernel.org, linux-acpi@vger.kernel.org, "linux-arm-kernel@lists.infradead.org" , Jon Masters , "patches@apm.com" , "Hurwitz, Sherry" , "Duran, Leo" , Hanjun Guo , Al Stone On 12/16/2015 11:04 AM, Mika Westerberg wrote: > On Tue, Dec 15, 2015 at 11:20:03AM -0800, Loc Ho wrote: >> Can we not just add an AML method that will return the operation clock >> frequency that the I2C driver can use? If the method doesn't existed, >> we will just bail and do nothing or assume what ever default behavior? > > Why would you add yet another method? There already are existing ACPI > *CNT methods that you can use, and are used in systems out there. One thing to remember that *CNT methods allow more precise machine and per bus specific tunings against different HW characteristics like pull-up resistance, line load, propagation delay, etc. -- Jarkko