From patchwork Tue May 30 10:09:28 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Miquel Raynal X-Patchwork-Id: 100719 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a59:994d:0:b0:3d9:f83d:47d9 with SMTP id k13csp2070536vqr; Tue, 30 May 2023 03:16:20 -0700 (PDT) X-Google-Smtp-Source: ACHHUZ4KxfgG3VXMd8sL1bSjMvkUfBKPRKMdmSJwHqoZkgeCZiAPnWaAA40XeQjG33tXiQnDbx6h X-Received: by 2002:a17:90a:bb91:b0:255:929c:5166 with SMTP id v17-20020a17090abb9100b00255929c5166mr2015641pjr.26.1685441780625; Tue, 30 May 2023 03:16:20 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1685441780; cv=none; d=google.com; s=arc-20160816; b=mkUhHxZ1sN6sBJ2SLWpomCNnTAfpdSHTQBeAl93STCf4Fko8My7MrSowAvINkygZus Xe2+lYx9eEAhAbKGz8FgySVVrlLiuodtjXcg5Ej5vEG8XeAZsDRs5cGnd/v90b1kRGbv rxbXin1CochwQKY7JADbjIL9kw4y9J66qNpz9thE0xFun8Z5wz9noS7JS9gPjUYZf20l Ufwj3Dn4iiKzXLuD2qB9+B13PDoIWug7rkevg8feD9Y4iFxEcXKuG1aOnIIBhEhdkBvY TrS+Exd4XBC/R/Xu2S2oTbZyfx1SaGKG4erg8Wqny68s5a3a8K6g0SyjsyrV/0MtrlhD A6Xw== 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=sGMXklHRpmowRNAZplbcx525aq6V1AzIWaohqk4ud74=; b=hwt95NF7/qLVZMRrazJ9XCRzA14/JQXRYNnHLBd/SirXXXo1uWJ/Y0aP9gLFZOog+G iNzZelGJjCn5uBeNUsJkG3RtVDxptIeu5R2pWJQ3ZzAioceKM034Ysu7IiL2CPEW9ucy +qstUBzjswC5osB1Vjx+lUAP1/SGYifLxe7dBHsbT9LoVXeVeYhzVNxaja/W/ld4qg8z KwE7Zc8ks89hZ2AlcawlWp3mGvG6BjzVqgO4NfGT/UvrELyAV1xDncrE9UZktkFRaZij R8MbZQ51qk+9ZavmbaXXUU44H4kdcqCO3iK2X32rt7ZZwOnESb/yeRgR79HvBcwS/pbs nFrg== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@bootlin.com header.s=gm1 header.b=nrvvN2Wv; 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 oa6-20020a17090b1bc600b0023fb875a929si11897536pjb.106.2023.05.30.03.16.06; Tue, 30 May 2023 03:16:20 -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=nrvvN2Wv; 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 S230475AbjE3KJl (ORCPT + 99 others); Tue, 30 May 2023 06:09:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44770 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229712AbjE3KJh (ORCPT ); Tue, 30 May 2023 06:09:37 -0400 Received: from relay7-d.mail.gandi.net (relay7-d.mail.gandi.net [217.70.183.200]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 27ECFAB for ; Tue, 30 May 2023 03:09:32 -0700 (PDT) X-GND-Sasl: miquel.raynal@bootlin.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1685441371; 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=sGMXklHRpmowRNAZplbcx525aq6V1AzIWaohqk4ud74=; b=nrvvN2WvhX4s87UxfKRyisDZwPKXvHTJmfnNskwPJ7Jn45Nz5jvtIQYX+NiueTwwrfIBc4 ujOR8HeDopnQeort1lxjGQYx4QDo3ywoFvTCUWVRBuREoi7CsFcbIU+PDJlX6eKvtHBN7d ygT4zn1u0cyiIDTCgnQUs+ISYgsdnKNZzEomPERAD3OzL1CVH/pHC3FBu2opLHhlLy2XZJ rmqcgjvN7tn3ZoZAKxdTpWAPH8w04hHCaHMcuAiOx2PPy3bwc5a9a2WaeTBbfSxig2XVox 7Ns9rMe6Mqjaz+sdbKhqPUq4vN8UNoBBq8TIpYwg7uexTquBedcOuqNyxvsqUg== X-GND-Sasl: miquel.raynal@bootlin.com X-GND-Sasl: miquel.raynal@bootlin.com X-GND-Sasl: miquel.raynal@bootlin.com X-GND-Sasl: miquel.raynal@bootlin.com X-GND-Sasl: miquel.raynal@bootlin.com X-GND-Sasl: miquel.raynal@bootlin.com Received: by mail.gandi.net (Postfix) with ESMTPSA id F04BE20008; Tue, 30 May 2023 10:09:30 +0000 (UTC) From: Miquel Raynal To: Srinivas Kandagatla Cc: Greg Kroah-Hartman , Luka Perkov , Robert Marko , Thomas Petazzoni , , Miquel Raynal Subject: [PATCH v2 1/2] ABI: sysfs-nvmem-cells: Expose cells through sysfs Date: Tue, 30 May 2023 12:09:28 +0200 Message-Id: <20230530100929.285235-2-miquel.raynal@bootlin.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230530100929.285235-1-miquel.raynal@bootlin.com> References: <20230530100929.285235-1-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?1767313800219976607?= X-GMAIL-MSGID: =?utf-8?q?1767313800219976607?= 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 | 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/ABI/testing/sysfs-nvmem-cells new file mode 100644 index 000000000000..bee4acc5bfcb --- /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 + + 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