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 C968FC7EE29 for ; Tue, 23 May 2023 10:02:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236439AbjEWKCy (ORCPT ); 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 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 -- 2.34.1