From patchwork Mon Feb 24 10:37:38 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Huang Shijie X-Patchwork-Id: 3708851 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id DF013BF13A for ; Mon, 24 Feb 2014 11:44:00 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 2000020149 for ; Mon, 24 Feb 2014 11:44:00 +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 21E4620131 for ; Mon, 24 Feb 2014 11:43:59 +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 1WHteJ-00038G-0j; Mon, 24 Feb 2014 11:24:40 +0000 Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1WHtdZ-0000b6-ED; Mon, 24 Feb 2014 11:23:53 +0000 Received: from va3ehsobe001.messaging.microsoft.com ([216.32.180.11] helo=va3outboundpool.messaging.microsoft.com) by merlin.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1WHtcO-0000OU-U4; Mon, 24 Feb 2014 11:22:58 +0000 Received: from mail58-va3-R.bigfish.com (10.7.14.249) by VA3EHSOBE012.bigfish.com (10.7.40.62) with Microsoft SMTP Server id 14.1.225.22; Mon, 24 Feb 2014 11:22:19 +0000 Received: from mail58-va3 (localhost [127.0.0.1]) by mail58-va3-R.bigfish.com (Postfix) with ESMTP id 728003800D3; Mon, 24 Feb 2014 11:22:19 +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(z551bizzz1f42h2148h208ch1ee6h1de0h1fdah2073h2146h1202h1e76h2189h1d1ah1d2ah1fc6h1082kzz1de098h8275bh1de097hz2dh2a8h839hd24he5bhf0ah1288h12a5h12a9h12bdh12e5h137ah139eh13b6h1441h1504h1537h162dh1631h1758h1898h18e1h1946h19b5h1ad9h1b0ah1b2fh2222h224fh1fb3h1d0ch1d2eh1d3fh1dfeh1dffh1e23h1fe8h1ff5h2218h2216h226dh22d0h24afh2327h2336h2438h2461h2487h24d7h2516h2545h255eh1155h) Received: from mail58-va3 (localhost.localdomain [127.0.0.1]) by mail58-va3 (MessageSwitch) id 1393240936997397_9070; Mon, 24 Feb 2014 11:22:16 +0000 (UTC) Received: from VA3EHSMHS015.bigfish.com (unknown [10.7.14.244]) by mail58-va3.bigfish.com (Postfix) with ESMTP id C72CF360055; Mon, 24 Feb 2014 11:22:16 +0000 (UTC) Received: from mail.freescale.net (70.37.183.190) by VA3EHSMHS015.bigfish.com (10.7.99.25) with Microsoft SMTP Server (TLS) id 14.16.227.3; Mon, 24 Feb 2014 11:22:16 +0000 Received: from az84smr01.freescale.net (10.64.34.197) by 039-SN1MMR1-001.039d.mgd.msft.net (10.84.1.13) with Microsoft SMTP Server (TLS) id 14.3.158.2; Mon, 24 Feb 2014 11:22:15 +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 s1OBLp2I016423; Mon, 24 Feb 2014 04:22:11 -0700 From: Huang Shijie To: Subject: [PATCH v5 4/8] Documentation: add the document for the SPI NOR framework Date: Mon, 24 Feb 2014 18:37:38 +0800 Message-ID: <1393238262-8622-5-git-send-email-b32955@freescale.com> X-Mailer: git-send-email 1.7.2.rc3 In-Reply-To: <1393238262-8622-1-git-send-email-b32955@freescale.com> References: <1393238262-8622-1-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-20140224_062241_346277_F680ADD3 X-CRM114-Status: GOOD ( 11.60 ) X-Spam-Score: 1.8 (+) Cc: angus.clark@st.com, shawn.guo@linaro.org, b44548@freescale.com, broonie@linaro.org, linux-doc@vger.kernel.org, b18965@freescale.com, 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 --- 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..b9585f8 --- /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 knows 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.