From patchwork Fri Feb 28 07:58:00 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Huang Shijie X-Patchwork-Id: 3739421 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id C50129F2F7 for ; Fri, 28 Feb 2014 08:43:55 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id E9C6F20266 for ; Fri, 28 Feb 2014 08:43:54 +0000 (UTC) Received: from casper.infradead.org (casper.infradead.org [85.118.1.10]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id F029720265 for ; Fri, 28 Feb 2014 08:43:53 +0000 (UTC) Received: from merlin.infradead.org ([2001:4978:20e::2]) by casper.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1WJJ2i-0003xZ-2M; Fri, 28 Feb 2014 08:43:40 +0000 Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1WJJ2d-0002fP-QT; Fri, 28 Feb 2014 08:43:36 +0000 Received: from ch1ehsobe001.messaging.microsoft.com ([216.32.181.181] helo=ch1outboundpool.messaging.microsoft.com) by merlin.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1WJJ2T-0002d3-Vu; Fri, 28 Feb 2014 08:43:26 +0000 Received: from mail188-ch1-R.bigfish.com (10.43.68.245) by CH1EHSOBE013.bigfish.com (10.43.70.63) with Microsoft SMTP Server id 14.1.225.22; Fri, 28 Feb 2014 08:43:04 +0000 Received: from mail188-ch1 (localhost [127.0.0.1]) by mail188-ch1-R.bigfish.com (Postfix) with ESMTP id D82283A03A2; Fri, 28 Feb 2014 08:43:04 +0000 (UTC) X-Forefront-Antispam-Report: CIP:70.37.183.190; KIP:(null); UIP:(null); IPV:NLI; H:mail.freescale.net; RD:none; EFVD:NLI X-SpamScore: 4 X-BigFish: VS4(z551bizzz1f42h2148h208ch1ee6h1de0h1fdah2073h2146h1202h1e76h2189h1d1ah1d2ah1fc6h1082kzz1de098h8275bh1de097hz2dh2a8h839hd24he5bhf0ah1288h12a5h12a9h12bdh12e5h137ah139eh13b6h1441h1504h1537h162dh1631h1758h1898h18e1h1946h19b5h1ad9h1b0ah1b2fh2222h224fh1fb3h1d0ch1d2eh1d3fh1dfeh1dffh1e23h1fe8h1ff5h2218h2216h226dh22d0h24afh2327h2336h2438h2461h2487h24d7h2516h2545h255eh25cch1155h) Received: from mail188-ch1 (localhost.localdomain [127.0.0.1]) by mail188-ch1 (MessageSwitch) id 1393576984385474_17576; Fri, 28 Feb 2014 08:43:04 +0000 (UTC) Received: from CH1EHSMHS022.bigfish.com (snatpool1.int.messaging.microsoft.com [10.43.68.244]) by mail188-ch1.bigfish.com (Postfix) with ESMTP id 4CCF8240081; Fri, 28 Feb 2014 08:43:04 +0000 (UTC) Received: from mail.freescale.net (70.37.183.190) by CH1EHSMHS022.bigfish.com (10.43.70.22) with Microsoft SMTP Server (TLS) id 14.16.227.3; Fri, 28 Feb 2014 08:43:03 +0000 Received: from az84smr01.freescale.net (10.64.34.197) by 039-SN1MMR1-004.039d.mgd.msft.net (10.84.1.14) with Microsoft SMTP Server (TLS) id 14.3.158.2; Fri, 28 Feb 2014 08:43:02 +0000 Received: from shlinux2.ap.freescale.net (shlinux2.ap.freescale.net [10.192.224.44]) by az84smr01.freescale.net (8.14.3/8.14.0) with ESMTP id s1S8gvO8030715; Fri, 28 Feb 2014 01:42:58 -0700 From: Huang Shijie To: Subject: [PATCH v5 4/8 fix] Documentation: add the document for the SPI NOR framework Date: Fri, 28 Feb 2014 15:58:00 +0800 Message-ID: <1393574280-17302-1-git-send-email-b32955@freescale.com> X-Mailer: git-send-email 1.7.2.rc3 In-Reply-To: <1393238262-8622-5-git-send-email-b32955@freescale.com> References: <1393238262-8622-5-git-send-email-b32955@freescale.com> MIME-Version: 1.0 X-OriginatorOrg: freescale.com X-FOPE-CONNECTOR: Id%0$Dn%*$RO%0$TLS%0$FQDN%$TlsDn% X-FOPE-CONNECTOR: Id%0$Dn%FREESCALE.MAIL.ONMICROSOFT.COM$RO%1$TLS%0$FQDN%$TlsDn% X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20140228_034326_116864_63F3CAEB X-CRM114-Status: GOOD ( 12.04 ) X-Spam-Score: 1.8 (+) Cc: angus.clark@st.com, shawn.guo@linaro.org, broonie@linaro.org, linux-doc@vger.kernel.org, linux-spi@vger.kernel.org, Huang Shijie , devicetree@vger.kernel.org, linux-mtd@lists.infradead.org, pekon@ti.com, sourav.poddar@ti.com, computersforpeace@gmail.com, lee.jones@linaro.org, linux-arm-kernel@lists.infradead.org X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=0.2 required=5.0 tests=BAYES_00,KHOP_BIG_TO_CC, RCVD_IN_DNSWL_MED, RP_MATCHES_RCVD, UNPARSEABLE_RELAY, UNRESOLVED_TEMPLATE autolearn=no version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP This patch adds the document for the SPI NOR framework. Signed-off-by: Huang Shijie --- fix a typo --- Documentation/mtd/spi-nor.txt | 59 +++++++++++++++++++++++++++++++++++++++++ 1 files changed, 59 insertions(+), 0 deletions(-) create mode 100644 Documentation/mtd/spi-nor.txt diff --git a/Documentation/mtd/spi-nor.txt b/Documentation/mtd/spi-nor.txt new file mode 100644 index 0000000..294d5b0 --- /dev/null +++ b/Documentation/mtd/spi-nor.txt @@ -0,0 +1,59 @@ + SPI NOR framework + ============================================ + +Part I - why we need this framework? +------------------------------------- + +The SPI bus controller only deals with the byte stream. +Some controller does not works like a SPI bus controller, it works +like a SPI NOR controller instead, such as the Freescale's QuadSPI controller. + +The Freescale's QuadSPI controller should know the NOR commands to +find the right LUT sequence. Unfortunately, the old code can not meet +this requirement. + +Part II - How does the framework work? +------------------------------------- + +This framework just adds a new layer between the MTD and the SPI bus driver. +With this new layer, the SPI NOR controller driver does not depend on the +m25p80 code anymore. + + Before this framework, the layer is like: + + MTD + ------------------------ + m25p80 + ------------------------ + SPI bus driver + ------------------------ + SPI NOR chip + + After this framework, the layer is like: + MTD + ------------------------ + SPI NOR framework + ------------------------ + m25p80 + ------------------------ + SPI bus driver + ------------------------ + SPI NOR chip + + With the SPI NOR controller driver(Freescale QuadSPI), it looks like: + MTD + ------------------------ + SPI NOR framework + ------------------------ + fsl-quadSPI + ------------------------ + SPI NOR chip + +Part III - How can the drivers use the framework +------------------------------------- + +The main API is the spi_nor_scan(). Before you call the hook, you should +initialize the necessary fields for spi_nor{}. +Please see the drivers/mtd/spi-nor/spi-nor.c for detail. +Please also reference to the fsl-quadspi.c when you want to write a new driver +for a SPI NOR controller.