From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751563AbbINFHQ (ORCPT ); Mon, 14 Sep 2015 01:07:16 -0400 Received: from mail-pa0-f43.google.com ([209.85.220.43]:36660 "EHLO mail-pa0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750968AbbINFHP (ORCPT ); Mon, 14 Sep 2015 01:07:15 -0400 Subject: Re: [PATCH-v5 RESEND 2/5] i2c: pxa: enable/disable i2c module across msg xfer To: Wolfram Sang References: <1440395978-9065-1-git-send-email-vaibhav.hiremath@linaro.org> <1440395978-9065-3-git-send-email-vaibhav.hiremath@linaro.org> <20150911185312.GA1516@katana> Cc: linux-arm-kernel@lists.infradead.org, robh+dt@kernel.org, robert.jarzmik@free.fr, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-i2c@vger.kernel.org, Yi Zhang From: Vaibhav Hiremath Message-ID: <55F655FC.8070308@linaro.org> Date: Mon, 14 Sep 2015 10:37:08 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.2.0 MIME-Version: 1.0 In-Reply-To: <20150911185312.GA1516@katana> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Saturday 12 September 2015 12:23 AM, Wolfram Sang wrote: > On Mon, Aug 24, 2015 at 11:29:35AM +0530, Vaibhav Hiremath wrote: >> From: Yi Zhang >> >> Enable i2c module/unit before transmission and disable when it >> finishes. >> >> why? >> It's because the i2c bus may be disturbed if the slave device, >> typically a touch, powers on. > > I am not convinced, "may disturb" is too weak for me. It would need a > way more detailed description of the problem which makes clear that > this mechanism is the only way to go forward. > Hmm, Ok. Not sure what else I can bring up here. > Can't you use Runtime PM for that? > I haven't tried it though, I can give a try and check. Thanks, Vaibhav