Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933272AbcLMOMU convert rfc822-to-8bit (ORCPT ); Tue, 13 Dec 2016 09:12:20 -0500 Received: from mail.kernel.org ([198.145.29.136]:46130 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932254AbcLMOMS (ORCPT ); Tue, 13 Dec 2016 09:12:18 -0500 MIME-Version: 1.0 In-Reply-To: References: <5173a9456c423025d8f15baafa2499440cbe1b51.1481131072.git.lolivei@synopsys.com> <20161212170214.4cydp256jsp7srar@rob-hp-laptop> From: Rob Herring Date: Tue, 13 Dec 2016 08:11:49 -0600 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v4 3/5] i2c: designware: Add slave definitions To: Luis de Oliveira Cc: "wsa@the-dreams.de" , "mark.rutland@arm.com" , "jarkko.nikula@linux.intel.com" , "andriy.shevchenko@linux.intel.com" , "mika.westerberg@linux.intel.com" , "linux-i2c@vger.kernel.org" , "devicetree@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "Ramiro.Oliveira@synopsys.com" , "Joao.Pinto@synopsys.com" , "CARLOS.PALMINHA@synopsys.com" Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2397 Lines: 47 Again, please don't top post. And your line wrapping is messed up. IOW, you can't use Outlook. On Tue, Dec 13, 2016 at 4:50 AM, Luis de Oliveira wrote: > The controller for i2c-designware cannot be slave/master at the same time and it has to be enabled knowing beforehand if we want it to be slave or master by something outside of the controller itself. > > I as looking and I see the use of this I2C_OWN_SLAVE_ADDRESS with the "linux,slave-24c02" slave interface but I am not seeing how it will help me identify a selected i2c-designware block as a "slave" device before instantiation. I'm sorry if I'm not understanding properly. > I use the "linux,slave-24c02" to instantiate the i2c-designware as a slave with an address so I can do write/read operations, it is how I tested it. Something like this: of_for_each_child_node(child) { of_property_read_u32(child, "reg", ®); if (reg & I2C_OWN_SLAVE_ADDRESS)) im_a_slave = true; } ...rather than testing "mode" is equal to "slave". Rob > > Luis > > -----Original Message----- > From: Rob Herring [mailto:robh@kernel.org] > Sent: Monday, December 12, 2016 23:16 > To: Luis de Oliveira > Cc: wsa@the-dreams.de; mark.rutland@arm.com; jarkko.nikula@linux.intel.com; andriy.shevchenko@linux.intel.com; mika.westerberg@linux.intel.com; linux-i2c@vger.kernel.org; devicetree@vger.kernel.org; linux-kernel@vger.kernel.org; Ramiro.Oliveira@synopsys.com; Joao.Pinto@synopsys.com; CARLOS.PALMINHA@synopsys.com > Subject: Re: [PATCH v4 3/5] i2c: designware: Add slave definitions > > On Mon, Dec 12, 2016 at 12:35 PM, Luis de Oliveira wrote: >> Hi all, > > Please don't top post. > >> >> The slave address could be set by the I2C slave backend so I can't use it to setup the controller. >> A boolean property was my initial approach then Andy and Wolfram Sang suggested the use of compatible strings and later It was suggested to use a property to select mode but I can do it again if it's the best way. >> Can you please tell me where should it be documented? > > bindings/i2c/i2c.txt. > > Actually, looking at this some more, we already have a way to describe the controller being a slave device with the I2C_OWN_SLAVE_ADDRESS flag in the reg property. We should just need a helper to read reg property of each child and check for the bit set. > > Rob