From nobody Wed Dec 17 07:29:18 2025 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 E45EAC4167B for ; Wed, 29 Nov 2023 16:38:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231241AbjK2QiC (ORCPT ); Wed, 29 Nov 2023 11:38:02 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34142 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230480AbjK2Qhk (ORCPT ); Wed, 29 Nov 2023 11:37:40 -0500 Received: from relay6-d.mail.gandi.net (relay6-d.mail.gandi.net [IPv6:2001:4b98:dc4:8::226]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0237CD68 for ; Wed, 29 Nov 2023 08:37:45 -0800 (PST) Received: by mail.gandi.net (Postfix) with ESMTPSA id 0A45CC000A; Wed, 29 Nov 2023 16:37:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1701275864; 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=dfOp8t/SWXoAMbVxsmdWr6p/Yay0CylcPPBrARczmbM=; b=glZ3NGop0Vb3y9yDIWz+FYhMiWC3A2/Qs+sB8aCJs4shCfLbbrdzLgFlBZH7U4NCP2hH3M uiZ7W0l6QlITXpQFguGB5TyBLybUtGZbbUqAkCoT5J7rWMYJJl+a0gUENQh4FCa0r/9vUh FMUxpF7jYg3nbT3QDvPlKRiZZxV+sbAqZYhdqy++kyaDRsQW1K9/bQ6MLpQxiFrVz7k7ZV eNeI2ngePFYnurOdtxBmZZoVnMIYiLC+lmYD9SskT8jed12thZJHAgh+MIEQpu4FXroxUt aosXNCM4qOIuMlQWoDnacpGUaIYNzPd6X6GgTLTLUlMrJpoJr/ieB6dqryEiEw== From: Miquel Raynal To: Srinivas Kandagatla , Greg Kroah-Hartman , Cc: Thomas Petazzoni , Robert Marko , Luca Ceresoli , Michael Walle , =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= , Marco Felsch , Randy Dunlap , Chen-Yu Tsai , Daniel Golle , Miquel Raynal Subject: [PATCH v14 7/8] ABI: sysfs-nvmem-cells: Expose cells through sysfs Date: Wed, 29 Nov 2023 17:37:36 +0100 Message-Id: <20231129163737.698317-8-miquel.raynal@bootlin.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20231129163737.698317-1-miquel.raynal@bootlin.com> References: <20231129163737.698317-1-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 | 21 +++++++++++++++++++++ 1 file changed, 21 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..7af70adf3690 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-nvmem-cells @@ -0,0 +1,21 @@ +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: @, with + being the cell name and its location in the NVMEM + device, in hexadecimal (without the '0x' prefix, to mimic device + tree node names). 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@d + 00000000 54 4e 34 38 4d 2d 50 2d 44 4e |TN48M-P-DN| + 0000000a --=20 2.34.1