Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753384AbbFDPaB (ORCPT ); Thu, 4 Jun 2015 11:30:01 -0400 Received: from mail-out.m-online.net ([212.18.0.9]:57008 "EHLO mail-out.m-online.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752108AbbFDP3j (ORCPT ); Thu, 4 Jun 2015 11:29:39 -0400 X-Auth-Info: 1WSQRaHdjJYrlb4yMKO006dLzr4WPpPz0ZhdEB/HEbM= From: Marek Vasut To: Michal Suchanek Subject: Re: [PATCH 04/11] mtd: ofpart: do not fail probe when no partitions exist Date: Thu, 4 Jun 2015 17:28:50 +0200 User-Agent: KMail/1.13.7 (Linux/3.14-2-amd64; KDE/4.13.1; x86_64; ; ) Cc: Rob Herring , Pawel Moll , Mark Rutland , Ian Campbell , Kumar Gala , Russell King , Kukjin Kim , Krzysztof Kozlowski , Vinod Koul , Dan Williams , David Woodhouse , Brian Norris , Han Xu , Mark Brown , Geert Uytterhoeven , =?utf-8?q?Rafa=C5=82_Mi=C5=82ecki?= , Alison Chaiken , Huang Shijie , Ben Hutchings , Knut Wohlrab , "Bean Huo =?utf-8?q?=E9=9C=8D=E6=96=8C=E6=96=8C?= (beanhuo)" , "grmoore@altera.com" , devicetree , Linux Kernel Mailing List , "linux-arm-kernel@lists.infradead.org" , "linux-samsung-soc" , dmaengine , linux-mtd@lists.infradead.org, "linux-spi" References: <201506040058.52882.marex@denx.de> In-Reply-To: MIME-Version: 1.0 Content-Type: Text/Plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Message-Id: <201506041728.50227.marex@denx.de> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2605 Lines: 69 On Thursday, June 04, 2015 at 06:54:00 AM, Michal Suchanek wrote: > On 4 June 2015 at 00:58, Marek Vasut wrote: > > On Wednesday, June 03, 2015 at 11:26:40 PM, Michal Suchanek wrote: > >> On Exynos it is necessary to set SPI controller parameters that apply to > >> a SPI slave in a DT subnode of the slave device. The ofpart code returns > >> an error when there are subnodes of the SPI flash but no partitions are > >> found. Change this condition to a warning so that flash without > >> partitions can be accessed on Exynos. > > > > I have to admit the rationale for this patch is not very clear to me, > > sorry. Can you please explain this a bit more ? > > This is how the DT entry for SPI slave looks with s3c64xx: > flash: m25p80@0 { > #address-cells = <1>; > #size-cells = <1>; > compatible = "jedec,spi-nor"; > reg = <0>; > spi-max-frequency = <40000000>; > linux,max_tx_len = <65536>; SIDENOTE: I thought this was actually added by your patch #8 in this series. The underscores in the name of the property are not really consistent with the rest of the names. > m25p,fast-read; > controller-data { > samsung,spi-feedback-delay = <0>; > }; > }; > > this is example of flash partitions: > flash@0 { > #address-cells = <1>; > #size-cells = <1>; > > partition@0 { > label = "u-boot"; > reg = <0x0000000 0x100000>; > read-only; > }; > > uimage@100000 { > reg = <0x0100000 0x200000>; > }; > }; > > The parser ignores any flash without subnodes and returns 0 (no > partititon). When there is a subnode it assumes the flash is > partitioned and tries to parse the subnodes as partitions. When there > are subnodes and none parses as partition an error is returned. As > shown above it is valid to have subnodes on unpartitioned flash. > > When an error is returned from a partition parser the mtdpart code > passes on this error to the flash probe function and the proble of the > flash fails. What does /proc/mtd tell you when you have no partitions defined in the DT ? It should provide you with the entire MTD device and the code shouldn't even try to parse any OF partitions, since you don't have any. Best regards, Marek Vasut -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/