From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 C4F6C15E8B; Mon, 30 Dec 2024 15:58:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1735574296; cv=none; b=Fj3aFpRjvqbICFUg+8bk5ApMote7Pb4ab2Cawo3Qzzp/Nfe0r3knvMlWaOiIKH3WxjyAOi7frPxc1OuXvbxwR2+3cPgPloC0XlniyRQaRQ4izGDNmUL2nhSgop6GW92xw74GfCqh5bmbnEEbiHTaGaIdEgwJv+Ux8g2k0OvH6C4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1735574296; c=relaxed/simple; bh=quwerHeuEVdLG+kxen0dcGfV3REKumyQg9x8iTZFLrU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=OBH1ucrc0EKNZ86sW2iSjVoPc/5/Rf6KDGSs+A9HnTL/JR6Xj8rHHBz7W218eogJtv3Yu5eP+u7jChmC6giH23HZlCPB2oq6U5D6Gg0/d1k4J470NOW9ILZoxEjAVvJjGRqXtFKSnlEaubux7PaTzyuFDPg3wg/YCO92T/gHT1s= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=JQemvApf; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="JQemvApf" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F41F1C4CED0; Mon, 30 Dec 2024 15:58:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1735574296; bh=quwerHeuEVdLG+kxen0dcGfV3REKumyQg9x8iTZFLrU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=JQemvApfkhl5v2jNjO/LjHJf6qep1lnDb8yjLKoY2lv6v3jj9/5HXtE2HZUWx1LTL 3dcP7PGfavuc48LdMPWeyBfJrnycqj4EgwbAjDfOwVUkjVDPf5BaNjQrqLu0l20E9J flNB13CjHeKkTzyikkiaEjBcZiHv1hFc+co+sbuI= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Conor Dooley , Andi Shyti Subject: [PATCH 6.12 095/114] i2c: microchip-core: fix "ghost" detections Date: Mon, 30 Dec 2024 16:43:32 +0100 Message-ID: <20241230154221.757433033@linuxfoundation.org> X-Mailer: git-send-email 2.47.1 In-Reply-To: <20241230154218.044787220@linuxfoundation.org> References: <20241230154218.044787220@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Conor Dooley commit 49e1f0fd0d4cb03a16b8526c4e683e1958f71490 upstream. Running i2c-detect currently produces an output akin to: 0 1 2 3 4 5 6 7 8 9 a b c d e f 00: 08 -- 0a -- 0c -- 0e -- 10: 10 -- 12 -- 14 -- 16 -- UU 19 -- 1b -- 1d -- 1f 20: -- 21 -- 23 -- 25 -- 27 -- 29 -- 2b -- 2d -- 2f 30: -- -- -- -- -- -- -- -- 38 -- 3a -- 3c -- 3e -- 40: 40 -- 42 -- 44 -- 46 -- 48 -- 4a -- 4c -- 4e -- 50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 60: 60 -- 62 -- 64 -- 66 -- 68 -- 6a -- 6c -- 6e -- 70: 70 -- 72 -- 74 -- 76 -- This happens because for an i2c_msg with a len of 0 the driver will mark the transmission of the message as a success once the START has been sent, without waiting for the devices on the bus to respond with an ACK/NAK. Since i2cdetect seems to run in a tight loop over all addresses the NAK is treated as part of the next test for the next address. Delete the fast path that marks a message as complete when idev->msg_len is zero after sending a START/RESTART since this isn't a valid scenario. CC: stable@vger.kernel.org Fixes: 64a6f1c4987e ("i2c: add support for microchip fpga i2c controllers") Signed-off-by: Conor Dooley Reviewed-by: Andi Shyti Link: https://lore.kernel.org/r/20241218-outbid-encounter-b2e78b1cc707@spud Signed-off-by: Andi Shyti Signed-off-by: Greg Kroah-Hartman --- drivers/i2c/busses/i2c-microchip-corei2c.c | 2 -- 1 file changed, 2 deletions(-) --- a/drivers/i2c/busses/i2c-microchip-corei2c.c +++ b/drivers/i2c/busses/i2c-microchip-corei2c.c @@ -287,8 +287,6 @@ static irqreturn_t mchp_corei2c_handle_i ctrl &= ~CTRL_STA; writeb(idev->addr, idev->base + CORE_I2C_DATA); writeb(ctrl, idev->base + CORE_I2C_CTRL); - if (idev->msg_len == 0) - finished = true; break; case STATUS_M_ARB_LOST: idev->msg_err = -EAGAIN;