From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f52.google.com (mail-wm1-f52.google.com [209.85.128.52]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 27A9B38F944 for ; Thu, 5 Feb 2026 10:29:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.52 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770287394; cv=none; b=JpGinmmtUvduFxpi0gpq5+b8Azh7NNC5OwcGRhyA9LmM/kE019G7d7Y9P+gDqZgWOOIe1OZ59gXUTP8gB6gH5WAKthFGti480+8QyRnxjsL1qXU/a0HBiPqhSWkG0/rdTuYn8z8MNAwLiyF7JDMNQdRsclN/FZh2DWatP1KoOWc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770287394; c=relaxed/simple; bh=iCMMOuNbhHu1PgVAZgbxHKPmKrqrfHxjiWy2rfsDFH4=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=tFn5TPm2fPEOWQZxiRu4V9MxeYnYgMi1SUehiNtUuGqwdz8NiqbyUmE5JgQkZBSqH2GkFaYQsO31awVQqUwQOt/zUbZ3dio+rGmyHEONFZxvcrWlpe9R8nivWa/1IPq09Xl36me4sIaEjDC3bUZjHN2kPUR8jkfVEcqBSBZAP3o= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=JPxytzaX; arc=none smtp.client-ip=209.85.128.52 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="JPxytzaX" Received: by mail-wm1-f52.google.com with SMTP id 5b1f17b1804b1-4806d23e9f1so8258755e9.2 for ; Thu, 05 Feb 2026 02:29:53 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1770287392; x=1770892192; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=wtfgkFNYt3Wxt+KtLhLBhE2nyxyzaqciQiwFpAEbbKo=; b=JPxytzaXH3yDabJKJKETpwU3Ze6Sjv5tVD82bRGvWLqJdwiWbodmyK00Q1xpexf7Iz ETr98/Xwun4urK+glb85i6bRJIGmRck/Fzbyd+UiTXmLcuz6B/8wnR7UdigyKxQi5Ekq FJwg1XxgHl0D+dE8+mpFHhDvtsQDixCN1hoiJ2IIzoz4ON3cRjMdllRSsDBjCyMn6jNd Ef/A0vfXWQn7h4JVGNe6rv4aOGfzNDdVdjyiVCFHU4iURCL4T3j2ALWiztNX4kg0Dxyb klmYg4bW5fvPI0sjcb5LOkP/NgTliV6lGyuZvE53wB2qn0KB//rfv4LV7LdKCpXzJbPs irRQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1770287392; x=1770892192; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=wtfgkFNYt3Wxt+KtLhLBhE2nyxyzaqciQiwFpAEbbKo=; b=tvW4NmEVUxknsWORUm/rFjqVFatJpVRhOaGYIC9Qeq2xioqGMzGh7QH//DYLYnliGZ fwzxf87Tjv9gcYAhxEkshNdQMkK1hTrqUtjiuLIzathJyMFoig46h/uJHxkmW+g4O7dv j7NPgRnR0/PuzGpt2OFKaFA2uyM4/5Gk/ntQVS7n2Ss1AM4xnEKwf0Gm1ikj/JTYBcI/ Sr5ioJKDvOT2zlYF6852SGW+YVhtYrz9b49iakfDA4KdtbZbiTd8yZO3zfA78skNrvY4 iv6YpKQhDeLJsGEDsmvVLQvfVbiKL6t5ggpGos3B0gbY+VZWwr34vG7E7cMuaHKGPmH1 RH3Q== X-Forwarded-Encrypted: i=1; AJvYcCXJuc6HZGZOmml+cHBZ9XFAO8jBMvvebpyNjwtt/Bov4CiV3LBM1OjANLs5mlVV94Lj8wTYT5sLTNg=@vger.kernel.org X-Gm-Message-State: AOJu0YzQWf0Vtj/7faCs46wF1kXTYC/5iGpfxun3vTAo8nfW5XqrYYsi VdvCq4S6ak8luJ92xkzszYL2XD/9N9VFWPvcoDpJ0aCIMCsXoztXwxSX X-Gm-Gg: AZuq6aLxo2PNGZum+0d49peTW3p8isGezhlBgDXonBan30A305eH23ohW9tPRUfMEgQ iyP1NEDpR02Ipl1rKIUwDtAw9oF8vTj5bFT0w89r3RQZrrqvSH/kQlPE6OtvUnY2WLyjMpjR8jH pbavBq1geDoRx35TckUg/iAaZCYQKDWJBWuVzh/Q8iOX2bE05327mnvJDMnOSakW5AphZAdRRkK qA8EJSMzmv27PnRWGJDmu0dCVuKk68TwwXikbr60KFDRwzYk+eu16elp6xBYYcLl0tSF4Yk6mCl b0pXvsfXrdJGzcw3BKUoX0K8/iW69fKINp1Ux8pH3SQIHKHdNHJBedgpH89m30Ts6Oxkvy6E3qj iL78RJAS10ezmq0V8Hq6f2DxzAv/IcgPF+bPUMfusXHDTxLK4ipqk8KNDvaNz/r/gv4FUxvgNMp +MI/uhXEuT5WCS7sVlhBeRTOXTOuRWUBCJ X-Received: by 2002:a05:600c:1f08:b0:480:1e92:dc65 with SMTP id 5b1f17b1804b1-4830e99db33mr95391745e9.31.1770287392294; Thu, 05 Feb 2026 02:29:52 -0800 (PST) Received: from localhost.localdomain ([196.191.61.3]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4830ec4a76esm67876655e9.1.2026.02.05.02.29.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 05 Feb 2026 02:29:51 -0800 (PST) From: Tinsae Tadesse To: Wolfram Sang , Jean Delvare , Andi Shyti , Guenter Roeck Cc: Tinsae Tadesse , linux-i2c@vger.kernel.org, linux-hwmon@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 0/2] i2c: i801: Detect SPD Write Disable and expose as adapter quirk Date: Thu, 5 Feb 2026 13:29:23 +0300 Message-ID: <20260205102942.28745-1-tinsaetadesse2015@gmail.com> X-Mailer: git-send-email 2.52.0 Precedence: bulk X-Mailing-List: linux-i2c@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Hi I2C and HWMON maintainers, Intel i801 SMBus controllers feature a "SPD Write Disable" bit in the SMBHSTCFG register. When set by firmware, the hardware silently blocks all write transactions to the SPD EEPROM address range (0x50-0x57) while allowing reads to succeed. This creates a significant issue for the spd5118 hwmon driver. The SPD5118 requires write access for switching between register pages to read temperature data, and for cache synchronization during suspend/resume. When SPD Write Disable is set and the spd5118 driver attempts write transactions, the bus will generate a storm of SMBus DEV_ERR messages. This patch series proposes a generic solution by: 1. Introducing a new adapter quirk flag in include/linux/i2c.h to communicate this hardware restriction. 2. Modifying drivers/i2c/i2c-i801.c to detect the SPD Write Disable bit and set the quirk flag. 3. Modifying drivers/hwmon/spd5118.c to check for this quirk during probe and fail cleanly, as write access is mandatory. By using this mechanism, we avoid embedding device-specific policies in the controller driver and provide client drivers with the necessary information to make an informed decision. Tinsae Tadesse (2): i2c: i801: Detect SPD Write Disable and expose as adapter quirk hwmon: spd5118: Fail probe if SPD writes are disabled drivers/hwmon/spd5118.c | 15 +++++++++++++++ drivers/i2c/busses/i2c-i801.c | 16 +++++++++++++++- include/linux/i2c.h | 3 +++ 3 files changed, 33 insertions(+), 1 deletion(-) -- 2.52.0