From nobody Mon Feb 9 12:08:04 2026 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 9353EC0015E for ; Mon, 17 Jul 2023 07:52:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230245AbjGQHwX (ORCPT ); Mon, 17 Jul 2023 03:52:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53504 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231186AbjGQHwD (ORCPT ); Mon, 17 Jul 2023 03:52:03 -0400 Received: from relay3-d.mail.gandi.net (relay3-d.mail.gandi.net [IPv6:2001:4b98:dc4:8::223]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 77576118 for ; Mon, 17 Jul 2023 00:51:53 -0700 (PDT) Received: by mail.gandi.net (Postfix) with ESMTPSA id 7811C60007; Mon, 17 Jul 2023 07:51:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1689580311; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=nH6/LjRkYId88yq613RlWdOphmfE4iRu7Ck+Oxwm0yc=; b=WDkqvzg8QAfJqTq4uPlJhLx4c7ON8Cote9uwAPhSzr8+CJy20QpkqHe28R/g8CfLl3pJuJ +QGUPfERJPkT6c9ZYfzQj8zwSFVhCzvCJxUGXrlLy5RzDHHSISRHCuxhSIgulWpbjB81KL 70XZc+DOzkMOjBw1uHYInwhVjcF/Y208/M96Yr1ZlfI2ltPEgV/x9VXYIGt46UuEYbNxhX XX45Bpn1e0TSLhRWK1pigr9VKlatROaI4ATRrdl7TgOp1ncXtdPWBXGcYR71sIBYoyS1+D 6Mv/8wk8U9BtgntdJqlGZRdlnhEAu0DUbpJnQd7+ZMreKIhEIsm+ediXMETSfQ== From: Miquel Raynal To: Srinivas Kandagatla , Greg Kroah-Hartman , Cc: Thomas Petazzoni , Robert Marko , Luka Perkov , Michael Walle , Randy Dunlap , Miquel Raynal Subject: [PATCH v6 1/3] ABI: sysfs-nvmem-cells: Expose cells through sysfs Date: Mon, 17 Jul 2023 09:51:45 +0200 Message-Id: <20230717075147.43326-2-miquel.raynal@bootlin.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230717075147.43326-1-miquel.raynal@bootlin.com> References: <20230717075147.43326-1-miquel.raynal@bootlin.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-GND-Sasl: miquel.raynal@bootlin.com Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" The binary content of nvmem devices is available to the user so in the easiest cases, finding the content of a cell is rather easy as it is just a matter of looking at a known and fixed offset. However, nvmem layouts have been recently introduced to cope with more advanced situations, where the offset and size of the cells is not known in advance or is dynamic. When using layouts, more advanced parsers are used by the kernel in order to give direct access to the content of each cell regardless of their position/size in the underlying device, but these information were not accessible to the user. By exposing the nvmem cells to the user through a dedicated cell/ folder containing one file per cell, we provide a straightforward access to useful user information without the need for re-writing a userland parser. Content of nvmem cells is usually: product names, manufacturing date, MAC addresses, etc, Signed-off-by: Miquel Raynal Reviewed-by: Greg Kroah-Hartman --- Documentation/ABI/testing/sysfs-nvmem-cells | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-nvmem-cells diff --git a/Documentation/ABI/testing/sysfs-nvmem-cells b/Documentation/AB= I/testing/sysfs-nvmem-cells new file mode 100644 index 000000000000..b2d15a8d36e5 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-nvmem-cells @@ -0,0 +1,19 @@ +What: /sys/bus/nvmem/devices/.../cells/ +Date: May 2023 +KernelVersion: 6.5 +Contact: Miquel Raynal +Description: + The "cells" folder contains one file per cell exposed by + the nvmem device. The name of the file is the cell name. + The length of the file is the size of the cell (when + known). The content of the file is the binary content of + the cell (may sometimes be ASCII, likely without + trailing character). + Note: This file is only present if CONFIG_NVMEM_SYSFS + is enabled. + + Example:: + + hexdump -C /sys/bus/nvmem/devices/1-00563/cells/product-name + 00000000 54 4e 34 38 4d 2d 50 2d 44 4e |TN48M-P-DN| + 0000000a --=20 2.34.1