Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758882Ab3GRLwR (ORCPT ); Thu, 18 Jul 2013 07:52:17 -0400 Received: from devils.ext.ti.com ([198.47.26.153]:34233 "EHLO devils.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756731Ab3GRLwP (ORCPT ); Thu, 18 Jul 2013 07:52:15 -0400 Message-ID: <51E7D6E1.3000208@ti.com> Date: Thu, 18 Jul 2013 17:22:01 +0530 From: Sourav Poddar User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2.28) Gecko/20120313 Thunderbird/3.1.20 MIME-Version: 1.0 To: Mark Brown CC: , , , , , Subject: Re: [RFC/PATCHv2 3/3] driver: spi: Add quad spi read support References: <1374141687-10790-1-git-send-email-sourav.poddar@ti.com> <1374141687-10790-4-git-send-email-sourav.poddar@ti.com> <20130718104414.GH22506@sirena.org.uk> In-Reply-To: <20130718104414.GH22506@sirena.org.uk> Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1839 Lines: 43 On Thursday 18 July 2013 04:14 PM, Mark Brown wrote: > On Thu, Jul 18, 2013 at 03:31:27PM +0530, Sourav Poddar wrote: >> Since, qspi controller uses quad read. >> >> Configuring the command register, if the transfer of data needs >> dual or quad lines. >> >> This patch has been done on top of the following patch[1], which is just the >> basic idea of adding dual/quad support in spi framework. >> $subject patch will undergo changes as the parent patch goes[1] >> >> [1]: http://comments.gmane.org/gmane.linux.kernel.spi.devel/14047 > Just as with commit IDs you should include a plain text description of > anything you link to so that people reading your e-mail can tell what > you're talking about without going on line. Ok, will keep that in mind for future. Just to give you a brief description here, Requirement is to have a dual/quad support in spi frameowrk, so that drivers can use multiple lines for data transfers. What patch[1] tries to does, is [1]: http://comments.gmane.org/gmane.linux.kernel.spi.devel/14047 is to add to each transfer the bitwidth it supports, so that that bitwidth information can be parsed in controller driver and can be used for respective read/writes. A typical usecase on my side is, I have a spansion flash connected to qspi. Flash device supports quad read with a certain read opcode(QUAD_READ). So, Whenever the opcode send is QUAD_READ, we will append that information as a bitwidth to the spi transfer. This information will be parsed by the controller driver and will be used to configure the cmd reg to do the particular type of reads. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/