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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1F271EB64DD for ; Mon, 7 Aug 2023 09:20:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231492AbjHGJU4 (ORCPT ); Mon, 7 Aug 2023 05:20:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52812 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231478AbjHGJUw (ORCPT ); Mon, 7 Aug 2023 05:20:52 -0400 Received: from relay1-d.mail.gandi.net (relay1-d.mail.gandi.net [217.70.183.193]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F2BB710EC for ; Mon, 7 Aug 2023 02:20:45 -0700 (PDT) Received: by mail.gandi.net (Postfix) with ESMTPSA id 92468240010; Mon, 7 Aug 2023 09:20:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1691400043; 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=zrbd4MQZkOGKQB45KGg8LvE/Sm+pVdcwlk6S0hIofJo=; b=SBjghr39VxDBMbWljvWynJZfKFYha7VU91vMNlYu2pZVRmJkHKfEm5XKZH+BG7gyg578OJ CiZz33ma25U+sYohl2VJrH6yfmflR8W6F6rZo9xwac9SQZO3VuJa8FbQA/8AumG1pNtU6z u4ByMuPmzj6+weOBuRP+iOPmYD852byq04ORQLOXey/it3qiZaWeUDAIrjUPkgX3Pk9IVQ XQWssPJfIHWEd+Ol8U+JWDnIzqnea1M97iyi9oTs64XjgEwlUOUCg/Ahs7myAKCVEYMpam dM4F6rP6T9JFiDp9+kvkmtaBM33zjwk3XH007Olh0u2qZH1E5+v5Z9FJoQOSJA== Date: Mon, 7 Aug 2023 11:20:40 +0200 From: Miquel Raynal To: Chen-Yu Tsai Cc: Srinivas Kandagatla , Greg Kroah-Hartman , Thomas Petazzoni , Robert Marko , Luka Perkov , Michael Walle , linux-kernel@vger.kernel.org, Randy Dunlap , Daniel Golle , =?UTF-8?B?UmFmYcWCIE1pxYJlY2tp?= Subject: Re: [PATCH v8 0/8] NVMEM cells in sysfs Message-ID: <20230807112040.55af2163@xps-13> In-Reply-To: References: <20230807082419.38780-1-miquel.raynal@bootlin.com> Organization: Bootlin X-Mailer: Claws Mail 4.0.0 (GTK+ 3.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-GND-Sasl: miquel.raynal@bootlin.com Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Chen-Yu, wenst@chromium.org wrote on Mon, 7 Aug 2023 16:57:03 +0800: > On Mon, Aug 7, 2023 at 4:24=E2=80=AFPM Miquel Raynal wrote: > > > > Hello, > > > > As part of a previous effort, support for dynamic NVMEM layouts was > > brought into mainline, helping a lot in getting information from NVMEM > > devices at non-static locations. One common example of NVMEM cell is the > > MAC address that must be used. Sometimes the cell content is mainly (or > > only) useful to the kernel, and sometimes it is not. Users might also > > want to know the content of cells such as: the manufacturing place and > > date, the hardware version, the unique ID, etc. Two possibilities in > > this case: either the users re-implement their own parser to go through > > the whole device and search for the information they want, or the kernel > > can expose the content of the cells if deemed relevant. This second > > approach sounds way more relevant than the first one to avoid useless > > code duplication, so here is a series bringing NVMEM cells content to > > the user through sysfs. > > > > Here is a real life example with a Marvell Armada 7040 TN48m switch: > > > > $ nvmem=3D/sys/bus/nvmem/devices/1-00563/ > > $ for i in `ls -1 $nvmem/cells/*`; do basename $i; hexdump -C $i | head= -n1; done > > country-code@77 > > 00000000 54 57 |TW| > > crc32@88 > > 00000000 bb cd 51 98 |..Q.| > > device-version@49 > > 00000000 02 |.| > > diag-version@80 > > 00000000 56 31 2e 30 2e 30 |V1.0.0| > > label-revision@4c > > 00000000 44 31 |D1| > > mac-address@2c > > 00000000 18 be 92 13 9a 00 |......| > > manufacture-date@34 > > 00000000 30 32 2f 32 34 2f 32 30 32 31 20 31 38 3a 35 39 |02/24/2021= 18:59| > > manufacturer@72 > > 00000000 44 4e 49 |DNI| > > num-macs@6e > > 00000000 00 40 |.@| > > onie-version@61 > > 00000000 32 30 32 30 2e 31 31 2d 56 30 31 |2020.11-V0= 1| > > platform-name@50 > > 00000000 38 38 46 37 30 34 30 2f 38 38 46 36 38 32 30 |88F7040/88= F6820| > > product-name@d > > 00000000 54 4e 34 38 4d 2d 50 2d 44 4e |TN48M-P-DN| > > serial-number@19 > > 00000000 54 4e 34 38 31 50 32 54 57 32 30 34 32 30 33 32 |TN481P2TW2= 042032| > > vendor@7b > > 00000000 44 4e 49 |DNI| > > > > This layout with a cells/ folder containing one file per cell has been > > legitimately challenged by John Thomson. I am not against the idea of > > having a sub-folder per cell but I did not find a relevant way to do > > that so for know I did not change the sysfs organization. If someone > > really wants this other layout, please provide a code snipped which I > > can integrate. > > > > Current support does not include: > > * The knowledge of the type of data (binary vs. ASCII), so by default > > all cells are exposed in binary form. > > * Write support. > > > > Changes in v8: > > * Fix a compilation warning whith !CONFIG_NVMEM_SYSFS. > > * Add a patch to return NULL when no layout is found (reported by Dan > > Carpenter). > > * Fixed the documentation as well as the cover letter regarding the > > addition of addresses in the cell names. =20 >=20 > It seems this version no longer creates cells for legacy DT layout format= s? > So while I assume the issue I ran into is fixed, I don't see any cells > created on the MT8183 either. >=20 > Is this intended? Not at all, but I am surprised they are no longer created. I will add fake cells and see how it behaves. Thanks for the feedback! Miqu=C3=A8l