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 1203722257E; Mon, 13 Oct 2025 15:10:17 +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=1760368217; cv=none; b=dfAU86wezMl+JaOMZzJvdzK1mSGZ/1vfnyyVRYKeBgCdugZxYDw+pirzRKv8FtY7/q7e0FbjTcR+zO5AZZZZFENKViMgR1uo7JYrDKrb94dLoDLwyxdIdZeP+/FjaeUFs8nVVxG+2jTEPpyRCimPwiZD6EB0wkeGqGlV5dBCSLE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760368217; c=relaxed/simple; bh=gIxdF2xdZFhXXz9Kfygt+8GVDtUS/d/nBs3muQMsJJs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=tG3r/+NAExU1P+kAdw9o+UHXdJGzMsGrJF1nJY0molEK++uvO+sMheTUizPGhhx/kkhSvBt+rwTAezYFPj+2RVglACRWh4YSdi/IOdBXope7G/znU1DZu6HhiZ6qO3Jh5cR6m/xQUXFzHBdfKofJ+WVOMDszP8CTFDFboaUYz2I= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=2EpDGRnK; 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="2EpDGRnK" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9705AC4CEE7; Mon, 13 Oct 2025 15:10:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1760368216; bh=gIxdF2xdZFhXXz9Kfygt+8GVDtUS/d/nBs3muQMsJJs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=2EpDGRnK9lOW1Aj4U9chIHlpqaI4hSOrP5bFs9UYY9bQQQQaurEHZHaq/y45doRt9 o3uZk2/yKlniOUN+HdmqxO9lwEI68BXllWjtWY5NqYjlPuoyc5a7j2OI+KLaKnV/KD kVbb1y+ILHphk9SxRKmf7pAU3VwbYf6AF/bZmJ+8= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, "Leilk.Liu" , Chen-Yu Tsai , Wolfram Sang , Sasha Levin Subject: [PATCH 6.12 085/262] i2c: mediatek: fix potential incorrect use of I2C_MASTER_WRRD Date: Mon, 13 Oct 2025 16:43:47 +0200 Message-ID: <20251013144329.190995960@linuxfoundation.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20251013144326.116493600@linuxfoundation.org> References: <20251013144326.116493600@linuxfoundation.org> User-Agent: quilt/0.69 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-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Leilk.Liu [ Upstream commit b492183652808e0f389272bf63dc836241b287ff ] The old IC does not support the I2C_MASTER_WRRD (write-then-read) function, but the current code’s handling of i2c->auto_restart may potentially lead to entering the I2C_MASTER_WRRD software flow, resulting in unexpected bugs. Instead of repurposing the auto_restart flag, add a separate flag to signal I2C_MASTER_WRRD operations. Also fix handling of msgs. If the operation (i2c->op) is I2C_MASTER_WRRD, then the msgs pointer is incremented by 2. For all other operations, msgs is simply incremented by 1. Fixes: b2ed11e224a2 ("I2C: mediatek: Add driver for MediaTek MT8173 I2C controller") Signed-off-by: Leilk.Liu Suggested-by: Chen-Yu Tsai Reviewed-by: Chen-Yu Tsai Signed-off-by: Wolfram Sang Signed-off-by: Sasha Levin --- drivers/i2c/busses/i2c-mt65xx.c | 17 ++++++++++------- 1 file changed, 10 insertions(+), 7 deletions(-) diff --git a/drivers/i2c/busses/i2c-mt65xx.c b/drivers/i2c/busses/i2c-mt65xx.c index e0ba653dec2d6..8beef73960c74 100644 --- a/drivers/i2c/busses/i2c-mt65xx.c +++ b/drivers/i2c/busses/i2c-mt65xx.c @@ -1243,6 +1243,7 @@ static int mtk_i2c_transfer(struct i2c_adapter *adap, { int ret; int left_num = num; + bool write_then_read_en = false; struct mtk_i2c *i2c = i2c_get_adapdata(adap); ret = clk_bulk_enable(I2C_MT65XX_CLK_MAX, i2c->clocks); @@ -1256,6 +1257,7 @@ static int mtk_i2c_transfer(struct i2c_adapter *adap, if (!(msgs[0].flags & I2C_M_RD) && (msgs[1].flags & I2C_M_RD) && msgs[0].addr == msgs[1].addr) { i2c->auto_restart = 0; + write_then_read_en = true; } } @@ -1280,12 +1282,10 @@ static int mtk_i2c_transfer(struct i2c_adapter *adap, else i2c->op = I2C_MASTER_WR; - if (!i2c->auto_restart) { - if (num > 1) { - /* combined two messages into one transaction */ - i2c->op = I2C_MASTER_WRRD; - left_num--; - } + if (write_then_read_en) { + /* combined two messages into one transaction */ + i2c->op = I2C_MASTER_WRRD; + left_num--; } /* always use DMA mode. */ @@ -1293,7 +1293,10 @@ static int mtk_i2c_transfer(struct i2c_adapter *adap, if (ret < 0) goto err_exit; - msgs++; + if (i2c->op == I2C_MASTER_WRRD) + msgs += 2; + else + msgs++; } /* the return value is number of executed messages */ ret = num; -- 2.51.0