From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752264AbcAGAbj (ORCPT ); Wed, 6 Jan 2016 19:31:39 -0500 Received: from mail-lb0-f174.google.com ([209.85.217.174]:36281 "EHLO mail-lb0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751906AbcAGAbg (ORCPT ); Wed, 6 Jan 2016 19:31:36 -0500 MIME-Version: 1.0 In-Reply-To: <20160104161525.GC1599@katana> References: <1451920655-10798-1-git-send-email-Suravee.Suthikulpanit@amd.com> <20160104161525.GC1599@katana> Date: Wed, 6 Jan 2016 16:31:35 -0800 Message-ID: Subject: Re: [PATCH v4] i2c: designware: Do not require clock when SSCN and FFCN are provided From: Loc Ho To: Wolfram Sang Cc: Suravee Suthikulpanit , 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 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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