From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C88E3ECDFB8 for ; Fri, 20 Jul 2018 18:37:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3BB4820652 for ; Fri, 20 Jul 2018 18:37:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="ufOowqFB" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3BB4820652 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388212AbeGTT1G (ORCPT ); Fri, 20 Jul 2018 15:27:06 -0400 Received: from mail-lj1-f195.google.com ([209.85.208.195]:46194 "EHLO mail-lj1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731939AbeGTT1F (ORCPT ); Fri, 20 Jul 2018 15:27:05 -0400 Received: by mail-lj1-f195.google.com with SMTP id 203-v6so11855883ljj.13; Fri, 20 Jul 2018 11:37:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=JsWCJcXk2I5J9D+iQuR4M3uhG40dpNyDVB9MM87zk+U=; b=ufOowqFB6kYderNIXsh/2w8lJMWEhT50HKz1c3esgYpyOOwqzcYVPPkMtMFFX/nI/J bZDnDtsBUZG0QVeXaXtitJVmj249UJ06Vm2PlnYKqp9P9GKqaUugvM+VC4MSxmDKzBq+ kKY6q+fwDP4PqHWgFKJNtGC86Erb1nxHMqM8es+aQY7WaqkfOwF1TJb/POOUQiIRYQyc ODiD3QTQeYmi4Z6GfPSq8kzLgGVUGzeC2J3Fbtz4f9kYSw40arAiXCPddpnvvMR+23bx 0QQwlHJaeevwkHoVgjFsSumI88xxxxz6Y7l/FwVGIPql0bfxSzFhtgYcOnqWfXK9sh4B MhNg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=JsWCJcXk2I5J9D+iQuR4M3uhG40dpNyDVB9MM87zk+U=; b=eDJB6KVCxbOiwhm0B7G/kzFbsH+OzPMIYjz2HpYY3TwB2wVMiQTVtWOuR2NQJt9kCL IBfEdwUxEb3rowPGVP735yriggAnDOXwZA9xV2NrjnINH59G7lcZ8LLgs5xsYkWQeLuW v/SUPPavJFzYJjOCFnNKb9KcvP8U0TMe9QJDjIHS/yyjhV+fyNKHFfjBfDbmikCIfuUE 42nhjo6JJj0W2E5JCZ73w8EJrRzY3AKV/8FzgOY6Xh3zZ6k6pbXv769nSYMWL/pjNWtO OG4meACdC3b8QQJG37kw1mR/JU1vpGZCfhpiTdoCuD2CYQNDTG4/sXm4ZuKGQ9PklmOZ Ujgg== X-Gm-Message-State: AOUpUlHLE6QBCq7dGqHXX2/Xs9clvA4SowbDnut67P1lbCmh/YIF4FtA Q+4/C+JgUliHQUVc/Dl5F/w= X-Google-Smtp-Source: AAOMgpdax6nOBaAiZwuXfnW03xe/56py2jTUp/nknHUGjhioDBs/BCuYPj6OjOKDE+TK4SIZkkXG7w== X-Received: by 2002:a2e:9dc7:: with SMTP id x7-v6mr2366635ljj.142.1532111854007; Fri, 20 Jul 2018 11:37:34 -0700 (PDT) Received: from z50.localnet ([31.0.82.186]) by smtp.gmail.com with ESMTPSA id z7-v6sm387088lfg.89.2018.07.20.11.37.30 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 20 Jul 2018 11:37:33 -0700 (PDT) From: Janusz Krzysztofik To: Boris Brezillon Cc: Miquel Raynal , Tony Lindgren , Aaro Koskinen , Grygorii Strashko , Santosh Shilimkar , Kevin Hilman , Linus Walleij , Richard Weinberger , David Woodhouse , Brian Norris , Marek Vasut , linux-mtd@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-omap@vger.kernel.org, linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org, Artem Bityutskiy Subject: Re: [RFC PATCH 8/8] mtd: rawnand: ams-delta: Use GPIO callbacks for data I/O Date: Fri, 20 Jul 2018 20:38:15 +0200 Message-ID: <2165137.iTHcPHRtIn@z50> In-Reply-To: <20180719084749.25ca96a6@bbrezillon> References: <20180718235710.18242-1-jmkrzyszt@gmail.com> <20180718235710.18242-9-jmkrzyszt@gmail.com> <20180719084749.25ca96a6@bbrezillon> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Archived-At: List-Archive: List-Post: On Thursday, July 19, 2018 8:47:49 AM CEST Boris Brezillon wrote: > On Thu, 19 Jul 2018 01:57:10 +0200 > Janusz Krzysztofik wrote: > > > Don't readw()/writew() data directly from/to GPIO port which is under > > control of gpio-omap driver, use GPIO chip callbacks instead. > > > > Thanks to utilization of get/set_multiple() callbacks, performance > > degrade is minor for typical data transfers. > > Same comment here, don't use the gpio_chip hooks directly, use the > consumer API instead. I tired but performance was not acceptable. I see your point but please understand, what I'm trying to do here is not to develop a shiny general purpose fully GPIO based NAND driver, I'm trying to resolve issues with NAND driver for Amstrad Delta I like to play with, without loosing much performance. I'm going to reconsider all possible options, not only doing data I/O over GPIO inside the driver, to have the task completed. Once done, I can get back to the GPIO based code I developed so far and create a new generic driver as my free time permits, or anyone can do that if needed, the code is open source after all. Thanks, Janusz