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=-1.0 required=3.0 tests=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 70F34C4646D for ; Wed, 8 Aug 2018 17:42:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3AE4621771 for ; Wed, 8 Aug 2018 17:42:51 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3AE4621771 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=bootlin.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 S1729665AbeHHUDc convert rfc822-to-8bit (ORCPT ); Wed, 8 Aug 2018 16:03:32 -0400 Received: from mail.bootlin.com ([62.4.15.54]:42884 "EHLO mail.bootlin.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729221AbeHHUDb (ORCPT ); Wed, 8 Aug 2018 16:03:31 -0400 Received: by mail.bootlin.com (Postfix, from userid 110) id 6FDA22084E; Wed, 8 Aug 2018 19:42:45 +0200 (CEST) Received: from xps13 (unknown [91.224.148.103]) by mail.bootlin.com (Postfix) with ESMTPSA id 75D8D207E5; Wed, 8 Aug 2018 19:42:44 +0200 (CEST) Date: Wed, 8 Aug 2018 19:42:42 +0200 From: Miquel Raynal To: Janusz Krzysztofik Cc: Boris Brezillon , Linus Walleij , linux-omap@vger.kernel.org, Jonathan Corbet , Tony Lindgren , Richard Weinberger , linux-gpio@vger.kernel.org, Aaro Koskinen , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, Marek Vasut , linux-mtd@lists.infradead.org, Brian Norris , David Woodhouse , linux-arm-kernel@lists.infradead.org Subject: Re: [RFC PATCH v2 07/12] mtd: rawnand: ams-delta: Set port direction once per transfer Message-ID: <20180808194242.7540ce12@xps13> In-Reply-To: <3260564.acbQT1CZaz@z50> References: <20180718235710.18242-1-jmkrzyszt@gmail.com> <20180806222918.12644-8-jmkrzyszt@gmail.com> <20180807205752.32cd3e53@bbrezillon> <3260564.acbQT1CZaz@z50> Organization: Bootlin X-Mailer: Claws Mail 3.15.0-dirty (GTK+ 2.24.31; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Janusz, Janusz Krzysztofik wrote on Wed, 08 Aug 2018 18:55:35 +0200: > Hi Boris, > > On Tuesday, August 7, 2018 8:57:52 PM CEST Boris Brezillon wrote: > > On Tue, 7 Aug 2018 00:29:13 +0200 > > Janusz Krzysztofik wrote: > > > > > In its current shape, the driver sets data port direction before each > > > byte read/write operation, even during multi-byte transfers. Since > > > performance of the driver is completely not acceptable on Amstrad Delta > > > after it has been converted to GPIO bitbang, try to improve things a > > > bit by setting the port direction only on first byte of each transfer. > > ... > > I'd suggest a slightly different approach where the data pins > > direction state is stored in the the priv struct and only changed when > > required. This way you just have to add a test in > > ams_delta_read/write_byte(). > > Good idea, I'm going to use it, thanks. > > Once done, may I also move that one earlier in the series so that it can be > applied while our discussion on GPIO bitmap changes still continues? I think I may answer on his behalf: yes! You can move the GPIO bitmap changes at the end of the series, checking that you never break the bisectability. Then I could apply the major changes and let us iterate on the GPIO bitmap stuff only. Thanks, Miquèl