From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.tipi-net.de (mail.tipi-net.de [194.13.80.246]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A3B641547C0 for ; Sun, 29 Mar 2026 22:42:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=194.13.80.246 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774824172; cv=none; b=qPuAwdcIfI0ZodIA0DL2WASMSvfiQCENKoBtCmyD55HUw1mL/YtGd9GvZ3qw7hg5a9F2F66GtskeA9UfHSLvGyGUGtpe+JqcMKB68y93HoPMsybk9/GiTQE6muDBSPiOY9eMEFDlsIC6lLKYqhejUeUN69fspIs+AYfTYgPKYbQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774824172; c=relaxed/simple; bh=D/EETRuBRvXLCxFVJbBJqhykDeqaXnQZUxfjKU6RlAI=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=i+PVT+Yl72D994sIn5KGOWMfMX/Jg5b6T+w5bi20hGKsQFIuNHweBbSwQO3bqbsjcIqN7Ha8JV713vDiFVC0UOThsnglvqze6tQ8Gwp5nkY+qsH7D7HdJ5cjOIsn5aXvLhwdy3j5tefS/+I06iu/ITlfxiGNeHUd6JufOzWGhNQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=tipi-net.de; spf=pass smtp.mailfrom=tipi-net.de; dkim=pass (2048-bit key) header.d=tipi-net.de header.i=@tipi-net.de header.b=4R9gBMrw; arc=none smtp.client-ip=194.13.80.246 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=tipi-net.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=tipi-net.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=tipi-net.de header.i=@tipi-net.de header.b="4R9gBMrw" Received: from [127.0.0.1] (localhost [127.0.0.1]) by localhost (Mailerdaemon) with ESMTPSA id 84C1DA01B0; Mon, 30 Mar 2026 00:42:30 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=tipi-net.de; s=dkim; t=1774824151; h=from:subject:date:message-id:to:cc:mime-version: content-transfer-encoding; bh=dA4Rs9Jb5I2ZpDuifAoeSxEzZ8pORM0cDNmRTw+QskQ=; b=4R9gBMrwxdScZ8wGlCGUNtQdFzg/fPOnWlAKA4fGLblQ7IOezSzBbHmYgHDsYDBsgJ2dne LoOwj+Ln4ZEw2UOa3qObqYBK3JyjTurOLQpYnIvUD2wCtgFPX0PStK/Lg/A6kLk//Rt/zQ znk4jaQ1Md3eGjxH7XBRafMHlSebqhDdti/PaRsBbKBfK++IO0e2p+hMV83z4bZzYoOHdH xQbbpdfzAx2F3p98S7vGwpIp19304GGwZJK5cEpk97DYUH8g8jpOk8LrqebOjOo++Xgu4A z3/S30KuSJaV3dhrqtBRditQtCZ3gF2ypy4OdXzRc4p5/JO1MoI6ReWvG+fXMg== From: Nicolai Buchwitz To: netdev@vger.kernel.org Cc: Phil Elwell , Nicolai Buchwitz Subject: [PATCH net-next 0/2] net: phy: microchip: add downshift support for LAN88xx Date: Mon, 30 Mar 2026 00:41:58 +0200 Message-ID: <20260329224202.500229-1-nb@tipi-net.de> X-Mailer: git-send-email 2.51.0 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Last-TLS-Session-Version: TLSv1.3 Add standard ETHTOOL_PHY_DOWNSHIFT tunable support for the Microchip LAN88xx PHY, following the same pattern used by Marvell and other PHY drivers. Ethernet cables with faulty or missing pairs (specifically C and D) can successfully auto-negotiate 1000BASE-T but fail to establish a stable link. The LAN88xx PHY supports automatic downshift to 100BASE-TX after a configurable number of failed attempts (2-5). Patch 1 adds the get/set tunable implementation. Patch 2 enables downshift by default with a count of 2. Based on an earlier downstream implementation by Phil Elwell. Tested on Raspberry Pi 3B+ (LAN7515/LAN88xx). Nicolai Buchwitz (2): net: phy: microchip: add downshift tunable support for LAN88xx net: phy: microchip: enable downshift by default on LAN88xx drivers/net/phy/microchip.c | 96 +++++++++++++++++++++++++++++++++++- include/linux/microchipphy.h | 9 ++++ 2 files changed, 104 insertions(+), 1 deletion(-) -- 2.51.0