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GET /api/patches/2225725/?format=api
{ "id": 2225725, "url": "http://patchwork.ozlabs.org/api/patches/2225725/?format=api", "web_url": "http://patchwork.ozlabs.org/project/linux-i2c/patch/20260421140755.54222-1-marex@nabladev.com/", "project": { "id": 35, "url": "http://patchwork.ozlabs.org/api/projects/35/?format=api", "name": "Linux I2C development", "link_name": "linux-i2c", "list_id": "linux-i2c.vger.kernel.org", "list_email": "linux-i2c@vger.kernel.org", "web_url": "", "scm_url": "", "webscm_url": "", "list_archive_url": "", "list_archive_url_format": "", "commit_url_format": "" }, "msgid": "<20260421140755.54222-1-marex@nabladev.com>", "list_archive_url": null, "date": "2026-04-21T14:06:49", "name": "nvmem: core: eeprom: at24: Handle EEPROM with both read-only and wp-gpios", "commit_ref": null, "pull_url": null, "state": "new", "archived": false, "hash": "c69e05a74191239d3eafedee22ff0424f64a5424", "submitter": { "id": 91452, "url": "http://patchwork.ozlabs.org/api/people/91452/?format=api", "name": "Marek Vasut", "email": "marex@nabladev.com" }, "delegate": null, "mbox": "http://patchwork.ozlabs.org/project/linux-i2c/patch/20260421140755.54222-1-marex@nabladev.com/mbox/", "series": [ { "id": 500813, "url": "http://patchwork.ozlabs.org/api/series/500813/?format=api", "web_url": "http://patchwork.ozlabs.org/project/linux-i2c/list/?series=500813", "date": "2026-04-21T14:06:49", "name": "nvmem: core: eeprom: at24: Handle EEPROM with both read-only and wp-gpios", "version": 1, "mbox": "http://patchwork.ozlabs.org/series/500813/mbox/" } ], "comments": "http://patchwork.ozlabs.org/api/patches/2225725/comments/", "check": "pending", "checks": "http://patchwork.ozlabs.org/api/patches/2225725/checks/", "tags": {}, "related": [], "headers": { "Return-Path": "\n <linux-i2c+bounces-17119-incoming=patchwork.ozlabs.org@vger.kernel.org>", "X-Original-To": [ "incoming@patchwork.ozlabs.org", "linux-i2c@vger.kernel.org" ], "Delivered-To": "patchwork-incoming@legolas.ozlabs.org", "Authentication-Results": [ "legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=nabladev.com header.i=@nabladev.com header.a=rsa-sha256\n header.s=dkim header.b=SKXpzINo;\n\tdkim-atps=neutral", "legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org\n (client-ip=2600:3c09:e001:a7::12fc:5321; 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Tue, 21 Apr 2026 14:08:13 +0000 (UTC)", "from localhost.localdomain (localhost.localdomain [127.0.0.1])\n\tby smtp.subspace.kernel.org (Postfix) with ESMTP id 3CA333D7D7C;\n\tTue, 21 Apr 2026 14:08:10 +0000 (UTC)", "from mx.nabladev.com (mx.nabladev.com [178.251.229.89])\n\t(using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits))\n\t(No client certificate requested)\n\tby smtp.subspace.kernel.org (Postfix) with ESMTPS id 6153E3D7D8A;\n\tTue, 21 Apr 2026 14:08:06 +0000 (UTC)", "from [127.0.0.1] (localhost [127.0.0.1]) by localhost (Mailerdaemon)\n with ESMTPSA id 855D61147FA;\n\tTue, 21 Apr 2026 16:07:57 +0200 (CEST)" ], "ARC-Seal": "i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116;\n\tt=1776780489; cv=none;\n b=QChikO2MgPJrfBx+LYJ+BvzOd7uzZSfpVz6kIQ9YzmEun8wp3Gie03wiJ2U1fFsHYBzk5YV+Cqm57UTBBaL2XTDkQLdDn5NJctkYABc+kmul8yNW6aY21sQ1Iywe5jUFRByFK8bdo/8Ul6zO5ql2VGC8M6IHw4zUuDBvQch39Xg=", "ARC-Message-Signature": "i=1; a=rsa-sha256; d=subspace.kernel.org;\n\ts=arc-20240116; t=1776780489; c=relaxed/simple;\n\tbh=U3S/azcYtoK8lqyCMrjeJ/KYEZqdHpjzdHxJ59k4dfM=;\n\th=From:To:Cc:Subject:Date:Message-ID:MIME-Version;\n b=bTy2xQSItL8pwUlqY+fV2qaJkIXJcZu93yNvuvukwZxrz7Hps4o4A0PaaReCXg07oDczsnxdWS5qU0r02QBPYAytK+8zAycjIE6ddSz0nbCaddzb0msQShXGpP3VFfOiGKCAPPz50Dr+j99/xznFVD093BrGyEM6FFdkxcNgTws=", "ARC-Authentication-Results": "i=1; smtp.subspace.kernel.org;\n dmarc=pass (p=reject dis=none) header.from=nabladev.com;\n spf=pass smtp.mailfrom=nabladev.com;\n dkim=pass (2048-bit key) header.d=nabladev.com header.i=@nabladev.com\n header.b=SKXpzINo; arc=none smtp.client-ip=178.251.229.89", "DKIM-Signature": "v=1; a=rsa-sha256; c=relaxed/relaxed; d=nabladev.com;\n\ts=dkim; t=1776780478; h=from:subject:date:message-id:to:cc:mime-version:\n\t content-transfer-encoding; bh=ONHip1GbFzvZ4cejM52KSuI+49tZZL0UydKXrafRDOQ=;\n\tb=SKXpzINoETov8u3ksehh8NnLGkKRkat+0/W/iCk6kpxpKqDThTVnyISyVYkZOvY3SBS8Pv\n\t3tyV/6VCbGZ2GKw5DC4TW1wPLX5N3OPVgIoWAhESfDaeC1fAunBSAK3Nde8vufCTbu7xLI\n\t/r8dF46xPERu2Cu6s/jU0JFCNYCUdMLXZHq0y5nq9th70APWZY52ZdEYUmhz/jq9aM3WBh\n\t+bKHpqXhCCsjI5wHuUq8MVlvxbFgup1CDI47hhBWr4T2Vvh8gmNLjbi/pc99vzX1hO7Gqh\n\tKIvYzBhDRA7CukSE1+hylC1wCtrTvYaPeolxWjh2v9wn0EHl9s7S2phgzmSOJg==", "From": "Marek Vasut <marex@nabladev.com>", "To": "linux-i2c@vger.kernel.org", "Cc": "Marek Vasut <marex@nabladev.com>,\n\tArnd Bergmann <arnd@arndb.de>,\n\tBartosz Golaszewski <brgl@kernel.org>,\n\tGreg Kroah-Hartman <gregkh@linuxfoundation.org>,\n\tSrinivas Kandagatla <srini@kernel.org>,\n\tlinux-kernel@vger.kernel.org", "Subject": "[PATCH] nvmem: core: eeprom: at24: Handle EEPROM with both read-only\n and wp-gpios", "Date": "Tue, 21 Apr 2026 16:06:49 +0200", "Message-ID": "<20260421140755.54222-1-marex@nabladev.com>", "X-Mailer": "git-send-email 2.53.0", "Precedence": "bulk", "X-Mailing-List": "linux-i2c@vger.kernel.org", "List-Id": "<linux-i2c.vger.kernel.org>", "List-Subscribe": "<mailto:linux-i2c+subscribe@vger.kernel.org>", "List-Unsubscribe": "<mailto:linux-i2c+unsubscribe@vger.kernel.org>", "MIME-Version": "1.0", "Content-Transfer-Encoding": "8bit", "X-Last-TLS-Session-Version": "TLSv1.3" }, "content": "Handle special-case of AT24 EEPROM described in DT, which contains both\n\"read-only\" and \"wp-gpios\" properties. Interpret this configuration as\ndefault read-only, but with the possibility of unlock via force_ro sysfs\nattribute.\n\nFor this to work, the nvmem core must keep the \"nvmem\" sysfs bin attr as\nread-write, any writes into the bin attr which occur while the device is\nread-only are blocked in bin_attr_nvmem_write(). The AT24 EEPROM driver\nmust not mark the EEPROM as read-only if both \"read-only\" and \"wp-gpios\"\nDT properties are present.\n\nThe updated behavior can be tested as follows:\n\nCurrent content:\n\"\n$ hexdump -C /sys/bus/nvmem/devices/logging7/nvmem\n00000000 66 6f 6f 0a ff ff ff ff\n\"\n\nWrite into default-read-only device:\n\"\n$ echo bar > /sys/bus/nvmem/devices/logging7/nvmem\nbash: echo: write error: Operation not permitted\n$ cat /sys/bus/nvmem/devices/logging7/force_ro\n1\n\"\n\nUnlock and write into device:\n\"\n$ echo 0 > /sys/bus/nvmem/devices/logging7/force_ro\n$ cat /sys/bus/nvmem/devices/logging7/force_ro\n0\n\n$ echo bar > /sys/bus/nvmem/devices/logging7/nvmem\n$ hexdump -C /sys/bus/nvmem/devices/logging7/nvmem\n00000000 62 61 72 0a ff ff ff ff\n\"\n\nRelock and write into device, fails because device is read-only again:\n\"\n$ echo 1 > /sys/bus/nvmem/devices/logging7/force_ro\n$ echo baz > /sys/bus/nvmem/devices/logging7/nvmem\nbash: echo: write error: Operation not permitted\n\n$ hexdump -C /sys/bus/nvmem/devices/logging7/nvmem\n00000000 62 61 72 0a ff ff ff ff\n\"\n\nSigned-off-by: Marek Vasut <marex@nabladev.com>\n---\nCc: Arnd Bergmann <arnd@arndb.de>\nCc: Bartosz Golaszewski <brgl@kernel.org>\nCc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>\nCc: Srinivas Kandagatla <srini@kernel.org>\nCc: linux-i2c@vger.kernel.org\nCc: linux-kernel@vger.kernel.org\n---\n drivers/misc/eeprom/at24.c | 3 ++-\n drivers/nvmem/core.c | 3 +++\n 2 files changed, 5 insertions(+), 1 deletion(-)", "diff": "diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c\nindex 0200288d3a7ab..9ef00b0ce83d2 100644\n--- a/drivers/misc/eeprom/at24.c\n+++ b/drivers/misc/eeprom/at24.c\n@@ -627,7 +627,8 @@ static int at24_probe(struct i2c_client *client)\n \t\tpage_size = 1;\n \n \tflags = cdata->flags;\n-\tif (device_property_present(dev, \"read-only\"))\n+\tif (device_property_present(dev, \"read-only\") &&\n+\t !device_property_present(dev, \"wp-gpios\"))\n \t\tflags |= AT24_FLAG_READONLY;\n \tif (device_property_present(dev, \"no-read-rollover\"))\n \t\tflags |= AT24_FLAG_NO_RDROL;\ndiff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c\nindex 311cb2e5a5c02..c0eedfe8d706c 100644\n--- a/drivers/nvmem/core.c\n+++ b/drivers/nvmem/core.c\n@@ -282,6 +282,9 @@ static umode_t nvmem_bin_attr_get_umode(struct nvmem_device *nvmem)\n \tif (!nvmem->root_only)\n \t\tmode |= 0044;\n \n+\tif (nvmem->read_only && nvmem->reg_write)\n+\t\tmode |= 0200;\n+\n \tif (!nvmem->read_only)\n \t\tmode |= 0200;\n \n", "prefixes": [] }