From mboxrd@z Thu Jan 1 00:00:00 1970 From: Suravee Suthikulpanit Subject: Re: [PATCH v4] i2c: designware: Do not require clock when SSCN and FFCN are provided Date: Wed, 6 Jan 2016 23:05:14 -0600 Message-ID: <568DF20A.3060504@amd.com> References: <1451920655-10798-1-git-send-email-Suravee.Suthikulpanit@amd.com> <20160104161525.GC1599@katana> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail-bn1bon0080.outbound.protection.outlook.com ([157.56.111.80]:6016 "EHLO na01-bn1-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750707AbcAGFF1 (ORCPT ); Thu, 7 Jan 2016 00:05:27 -0500 In-Reply-To: Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Loc Ho , Wolfram Sang Cc: Mika Westerberg , jarkko.nikula@linux.intel.com, andriy.shevchenko@linux.intel.com, Ken Xue , linux-i2c@vger.kernel.org, linux-acpi@vger.kernel.org, Linux Kernel Mailing List Hi, On 01/06/2016 06:31 PM, Loc Ho wrote: > Hi All, > >>> The current driver uses input clock source frequency to calculate >>> values for [SS|FS]_[HC|LC] registers. However, when booting ACPI, we do not >>> currently have a good way to provide the frequency information. >>> Instead, we can leverage the SSCN and FFCN ACPI methods, which can be used >>> to directly provide these values. So, the clock information should >>> no longer be required during probing. >>> >>> However, since clk can be invalid, additional checks must be done where >>> we are making use of it. >>> >>> Signed-off-by: Mika Westerberg >>> Signed-off-by: Suravee Suthikulpanit >>> Tested-by: Loc Ho >>> --- >>> >>> Note: This has been tested on AMD Seattle RevB for both DT and ACPI. >>> >>> Changes from V3 (https://lkml.org/lkml/2015/12/22/596): >>> * Add i2c_dw_plat_prepare_clk() per Andy's suggestion >>> * Add tested-by Loc Ho. >> >> The changes from V3 are big enough that I'd appreciate a new Tested-by >> tag. > > I had tested this via this mixes of test cases: > > a. NO APD driver + this patch ==> HCNT/LCNT as expected > b. with APD driver + this patch ==> HCNT/LCNT as expected > c. with APD driver + this patch + double the frequency APD driver ==> > HCNT/LCNT as expected > d. with APD driver + this patch + double the frequency APD driver + > comment out the ACPI parameter retrieve ==> HCNT/LCNT changed as > expected > > Therefore, you can add my - Tested-by: Loc Ho > > -Loc > Thanks Loc, Suravee