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,URIBL_BLOCKED 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 61585C43615 for ; Tue, 21 Aug 2018 09:52:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 208A42170E for ; Tue, 21 Aug 2018 09:52:44 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 208A42170E 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 S1726877AbeHUNMJ convert rfc822-to-8bit (ORCPT ); Tue, 21 Aug 2018 09:12:09 -0400 Received: from mail.bootlin.com ([62.4.15.54]:37320 "EHLO mail.bootlin.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726684AbeHUNMJ (ORCPT ); Tue, 21 Aug 2018 09:12:09 -0400 Received: by mail.bootlin.com (Postfix, from userid 110) id CDCA620799; Tue, 21 Aug 2018 11:52:38 +0200 (CEST) Received: from xps13 (AAubervilliers-681-1-85-9.w90-88.abo.wanadoo.fr [90.88.27.9]) by mail.bootlin.com (Postfix) with ESMTPSA id 55911204AE; Tue, 21 Aug 2018 11:52:38 +0200 (CEST) Date: Tue, 21 Aug 2018 11:52:38 +0200 From: Miquel Raynal To: Naga Sureshkumar Relli Cc: Boris Brezillon , "richard@nod.at" , "dwmw2@infradead.org" , "computersforpeace@gmail.com" , "marek.vasut@gmail.com" , "kyungmin.park@samsung.com" , "absahu@codeaurora.org" , "peterpandong@micron.com" , "frieder.schrempf@exceet.de" , "linux-mtd@lists.infradead.org" , "linux-kernel@vger.kernel.org" , Michal Simek , "nagasureshkumarrelli@gmail.com" Subject: Re: [LINUX PATCH v10 1/2] dt-bindings: mtd: arasan: Add device tree binding documentation Message-ID: <20180821115238.1ad4dcb8@xps13> In-Reply-To: References: <1534511964-20342-1-git-send-email-naga.sureshkumar.relli@xilinx.com> <1534511964-20342-2-git-send-email-naga.sureshkumar.relli@xilinx.com> <20180820143324.61af9027@bbrezillon> <20180821075948.28962170@bbrezillon> Organization: Bootlin X-Mailer: Claws Mail 3.16.0 (GTK+ 2.24.32; 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 Naga, Naga Sureshkumar Relli wrote on Tue, 21 Aug 2018 09:22:07 +0000: > Hi Boris, > > > -----Original Message----- > > From: Boris Brezillon [mailto:boris.brezillon@bootlin.com] > > Sent: Tuesday, August 21, 2018 11:30 AM > > To: Naga Sureshkumar Relli > > Cc: miquel.raynal@bootlin.com; richard@nod.at; dwmw2@infradead.org; > > computersforpeace@gmail.com; marek.vasut@gmail.com; kyungmin.park@samsung.com; > > absahu@codeaurora.org; peterpandong@micron.com; frieder.schrempf@exceet.de; linux- > > mtd@lists.infradead.org; linux-kernel@vger.kernel.org; Michal Simek ; > > nagasureshkumarrelli@gmail.com > > Subject: Re: [LINUX PATCH v10 1/2] dt-bindings: mtd: arasan: Add device tree binding > > documentation > > > > On Tue, 21 Aug 2018 05:47:18 +0000 > > Naga Sureshkumar Relli wrote: > > > > > > > +Required properties: > > > > > +- compatible: Should be "xlnx,zynqmp-nand" or "arasan,nfc-v3p10" > > > > > > > > In your example it's not an "or" since both are defined. > > > In our previous discussion > > > (https://lore.kernel.org/patchwork/patch/748901/) > > > We decided to have compatible strings like " compatible = ",", > > "arasan,";" > > > So it should be either of these. > > > so I will write something like below > > > "Possible values are "xlnx,zynqmp-nand" > > > "arasan,nfc-v3p10" > > > And in example I will mention any one compatible. > > > Is it ok? > > > > Hm, why do you need arasan,nfc-v3p10 at all if it's supposed to be overloaded by a soc specific > > compat? > Actually we put these compatible strings based on the comments on v7 series. > Anyway I will just keep "xlnx,zynqmp-nand" as compatible. > > > > > > > + > > > > > +Optional properties: > > > > > +- arasan,has-mdma: Enables DMA support > > > > > > > > Can't you detect that based on the compatible (or thanks to a > > > > register). If it's something you choose when configuring the IP and can't detect at > > runtime I guess it's fine. > > > There is no way to select DMA when configuring the IP. > > > But it has internal DMA and there is a register to select PIO or DMA while starting a > > transfer. > > > So if user really don't want DMA, then we will never set DMA in the code based on DT > > property. > > > > If it's a purely SW choice, then is shouldn't be described in the DT. > > You can use a module param, but I'm not even sure why one would want to disable DMA. > UBIFS doesn't work with DMA, hence we are using a DT property to operate the driver in IO. > But as you pointed (use virt_is_valid()), with this we can switch our driver to operate in PIO or DMA. > I will remove this from DT. I don't get why UBIFS would not work with DMA? This is a significant drawback. Miquèl