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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no 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 01EABC433B4 for ; Fri, 16 Apr 2021 19:26:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CBC05611AF for ; Fri, 16 Apr 2021 19:26:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243009AbhDPT0d (ORCPT ); Fri, 16 Apr 2021 15:26:33 -0400 Received: from ssl.serverraum.org ([176.9.125.105]:37575 "EHLO ssl.serverraum.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235362AbhDPT0b (ORCPT ); Fri, 16 Apr 2021 15:26:31 -0400 Received: from ssl.serverraum.org (web.serverraum.org [172.16.0.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ssl.serverraum.org (Postfix) with ESMTPSA id 01C1022253; Fri, 16 Apr 2021 21:26:03 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=walle.cc; s=mail2016061301; t=1618601164; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=iOKsLNHAvUNt6FOKX0n36qA6s7ZucezMgWOSW4v76s8=; b=Hb1xtI/WzADiaRibdpmonxBtIdj9F1hpRIoWgSNvarzwJvNlayCeXjwOHk4k/q5vapGRy0 mZ4MWe8zwkie5eb66+W6rIaiyGkCEb3cCFQga8gMElsiMmwCxqHLmjmrU3+LW7L9M/xtGG VEhMEaxzSx5188bB+2nPXjtvkdJNma0= MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Date: Fri, 16 Apr 2021 21:26:03 +0200 From: Michael Walle To: Rob Herring Cc: linux-mtd@lists.infradead.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, Miquel Raynal , Richard Weinberger , Vignesh Raghavendra , Srinivas Kandagatla Subject: Re: [PATCH 0/5] mtd: core: OTP nvmem provider support In-Reply-To: <20210416184423.GA3715339@robh.at.kernel.org> References: <20210416114928.27758-1-michael@walle.cc> <20210416184423.GA3715339@robh.at.kernel.org> User-Agent: Roundcube Webmail/1.4.11 Message-ID: <9f33229a8fe83b49210289fc93a8554e@walle.cc> X-Sender: michael@walle.cc Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org Hi Rob, Am 2021-04-16 20:44, schrieb Rob Herring: > On Fri, Apr 16, 2021 at 01:49:23PM +0200, Michael Walle wrote: >> The goal is to fetch a (base) MAC address from the OTP region of a SPI >> NOR >> flash. >> >> This is the first part, where I try to add the nvmem provider support >> to >> the MTD core. >> >> I'm not sure about the device tree bindings. Consider the following >> two >> variants: >> >> (1) >> flash@0 { >> .. >> >> otp { >> compatible = "mtd-user-otp"; > > mtd is a linuxism. Why not just 'nvmem-cells' here or as a fallback if > we come up with a better name? There are two different compatibles: "mtd-user-otp" and "mtd-factory-otp" to differentiate what kind of OTP should be used (and both are possible at the same time). Thus nvmem-cells alone won't be enough. We could drop the "mtd-" prefix though. Is there a benefit of having the following? compatible = "user-otp", "nvmem-cells"; >> #address-cells = <1>; >> #size-cells = <1>; >> >> serial-number@0 { >> reg = <0x0 0x8>; >> }; >> }; >> }; >> >> (2) >> flash@0 { >> .. >> >> otp { >> compatible = "mtd-user-otp"; >> #address-cells = <1>; >> #size-cells = <1>; >> >> some-useful-name { >> compatible = "nvmem-cells"; >> >> serial-number@0 { >> reg = <0x0 0x8>; >> }; >> }; >> }; >> }; >> >> Both bindings use a subnode "opt[-N]". We cannot have the nvmem cells >> as >> children to the flash node because of the legacy partition binding. >> >> (1) seems to be the form which is used almost everywhere in the >> kernel. >> That is, the nvmem cells are just children of the parent node. >> >> (2) seem to be more natural, because there might also be other >> properties >> inside the otp subnode and might be more future-proof. >> >> At the moment this patch implements (1). > > I think approach (1) seems fine. ok -michael