From patchwork Tue May 23 10:02:38 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Miquel Raynal X-Patchwork-Id: 97948 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a59:b0ea:0:b0:3b6:4342:cba0 with SMTP id b10csp2024195vqo; Tue, 23 May 2023 03:09:19 -0700 (PDT) X-Google-Smtp-Source: ACHHUZ5tqO4r1BqenKeXqMJA2mWM6UDxaj/kR4gKMG1g34Ix+M4foqn2Hv1jE6sj+Y62QI/gJ6Ad X-Received: by 2002:a17:903:2310:b0:1ad:164:74fc with SMTP id d16-20020a170903231000b001ad016474fcmr18710125plh.20.1684836559074; Tue, 23 May 2023 03:09:19 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1684836559; cv=none; d=google.com; s=arc-20160816; b=c9WW+5wTsadFuw0kDaxKkzQ5m3cI8rVmRpJUGbZpIy5sIO70RHqVMvG3ZDracZCcX6 8Oj7mvwN8hp5ODDMJVQuUR0g2ChAi1NylTzbh/uTeuPJfFmMMlBr+59vZQdEz02Tua3h pnFUmm4cv12LscH/Eil7R0uhPkDROllTte5ESLdkYu4GaS3+mOyy6kbDFcb/NF3Ksict B99aSPKydrKikHk88jQMXSi99QvXg0l5akHkQrkOjHEPuteKpVicBkAZprmVro47JzON qXjtByENBhNL6r6NcD57tSj5WTjI6Pu4eSQ/hT3ZegxtetNwQvxoztLEdcm203K6QUL3 WyoQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from :dkim-signature; bh=KNg4TjzLvhlEcscaFo5K8pEbs3rTh0QVCliG109s52o=; b=Z4NPm/pD7axZc8y5G2NbJAFs5KfEFrZLmywklgPkBi+Axk5iSrJowAYBRSghSJU1Xm U+X7rpR3l2vMlgZHCdFeKIsSmzNna5nms2DZ0aDn54+iw4pIdsAPgivSCTsKiGohDs4y DX6JM/oD9LnB8s0rhbuJ1rAdPNuzcgLjwEpqH2OMRmTWJQfS51YpGoPhgqCJXnU8Rp9j kGQiT/VVC9RqOWNLMyrJD+MLIiPZ15ozTXdR9vhRm4gozHowud/upIQfRX9Tv7OyEF53 oMGGXc6TdqPffJObAUzM9PannuN/fKnfwx348MPwngSKhAUFnhkgjzgbwIlY4LO7L10H iXLw== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@bootlin.com header.s=gm1 header.b=WWfouuzy; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=bootlin.com Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id w10-20020a170902e88a00b001a9930c626dsi6721543plg.273.2023.05.23.03.09.04; Tue, 23 May 2023 03:09:19 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@bootlin.com header.s=gm1 header.b=WWfouuzy; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=bootlin.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236438AbjEWKCy (ORCPT + 99 others); Tue, 23 May 2023 06:02:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43122 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229921AbjEWKCu (ORCPT ); Tue, 23 May 2023 06:02:50 -0400 Received: from relay8-d.mail.gandi.net (relay8-d.mail.gandi.net [217.70.183.201]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 93099120 for ; Tue, 23 May 2023 03:02:43 -0700 (PDT) Received: (Authenticated sender: miquel.raynal@bootlin.com) by mail.gandi.net (Postfix) with ESMTPSA id 4491E1BF206; Tue, 23 May 2023 10:02:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1684836161; 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=KNg4TjzLvhlEcscaFo5K8pEbs3rTh0QVCliG109s52o=; b=WWfouuzyHd3/e7jqoI3BuqNOcTiiRoFUlWUvhovGT8L2eFiv7N0jLbG0imu+zg2hJ0e25t FjWx54XIckBPBIyOCAUo9br45Lj606A4YPe4KJek+9bNzmip/w1AOoxRhVFgft4Z10mhvP v3eL+71pWgFbrK0ERhn5EZvLoyOXrKtiA5VPDeo42OdJi1Bqk0eYz/hWG9j/5j6/lVRzwR g7xK3PyI16+OcNPGk3i46jI3llYdkjcNcfANI+2tPwOC41+Q4USLGPurg5MzeAQQQFnix0 dwCiX8TYY9lrE7Bu7ccLss6ZvPblA+s6xyekaAOgPqworjopHKANzzaMD79ifQ== From: Miquel Raynal To: Srinivas Kandagatla Cc: Greg Kroah-Hartman , Luka Perkov , Robert Marko , Thomas Petazzoni , , Miquel Raynal Subject: [PATCH 1/2] ABI: sysfs-nvmem-cells: Expose cells through sysfs Date: Tue, 23 May 2023 12:02:38 +0200 Message-Id: <20230523100239.307574-2-miquel.raynal@bootlin.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230523100239.307574-1-miquel.raynal@bootlin.com> References: <20230523100239.307574-1-miquel.raynal@bootlin.com> MIME-Version: 1.0 X-Spam-Status: No, score=-2.8 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_LOW,SPF_HELO_NONE, SPF_PASS,T_SCC_BODY_TEXT_LINE,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1766679180044671168?= X-GMAIL-MSGID: =?utf-8?q?1766679180044671168?= 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 --- 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/ABI/testing/sysfs-nvmem-cells new file mode 100644 index 000000000000..d0247bead8a1 --- /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 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). + There is currently no write permission but this could + evolve in the future if the need arises. + Note: This file is only present if CONFIG_NVMEM_SYSFS + is enabled + + ex:: + + 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