Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756948AbdDPWbs (ORCPT ); Sun, 16 Apr 2017 18:31:48 -0400 Received: from mail-wm0-f65.google.com ([74.125.82.65]:33080 "EHLO mail-wm0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756790AbdDPWbo (ORCPT ); Sun, 16 Apr 2017 18:31:44 -0400 Subject: Re: [PATCH v6 2/4] mtd: m25p80: add support of SPI 1-2-2 and 1-4-4 protocols To: Cyrille Pitchen , linux-mtd@lists.infradead.org, kdasu.kdev@gmail.com References: <48bacd7e2c6722789d15488f903a22abbac6a04a.1492374675.git.cyrille.pitchen@atmel.com> Cc: computersforpeace@gmail.com, dwmw2@infradead.org, boris.brezillon@free-electrons.com, richard@nod.at, linux-kernel@vger.kernel.org, jartur@cadence.com, mar.krzeminski@gmail.com From: Marek Vasut Message-ID: <86a7ceda-def7-dd3c-ad08-c17ecd363771@gmail.com> Date: Mon, 17 Apr 2017 00:28:40 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Icedove/45.4.0 MIME-Version: 1.0 In-Reply-To: <48bacd7e2c6722789d15488f903a22abbac6a04a.1492374675.git.cyrille.pitchen@atmel.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1308 Lines: 32 On 04/16/2017 11:41 PM, Cyrille Pitchen wrote: > Before this patch, m25p80_read() supported few SPI protocols: > - regular SPI 1-1-1 > - SPI Dual Output 1-1-2 > - SPI Quad Output 1-1-4 > On the other hand, m25p80_write() only supported SPI 1-1-1. > > This patch updates both m25p80_read() and m25p80_write() functions to let > them support SPI 1-2-2 and SPI 1-4-4 protocols for Fast Read and Page > Program SPI commands. > > It adopts a conservative approach to avoid regressions. Hence the new > implementations try to be as close as possible to the old implementations, > so the main differences are: > - the tx_nbits values now being set properly for the spi_transfer > structures carrying the (op code + address/dummy) bytes > - and the spi_transfer structure being split into 2 spi_transfer > structures when the numbers of I/O lines are different for op code and > for address/dummy byte transfers on the SPI bus. > > Besides, the current spi-nor framework supports neither the SPI 2-2-2 nor > the SPI 4-4-4 protocols. So, for now, we don't need to update the > m25p80_{read|write}_reg() functions as SPI 1-1-1 is the only one possible > protocol. > > Signed-off-by: Cyrille Pitchen Reviewed-by: Marek Vasut -- Best regards, Marek Vasut