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 2B90D1F1313; Mon, 13 Oct 2025 14:59:35 +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=1760367575; cv=none; b=WvK7Z/jaI6kqvvvbqlcLVkNa9PXbDjtJl7oVZup1V7no6mW7RNJUFk3l6eOxid23uVgXTnKEzmgVTHkhPmuC5ZV0o8hqv/ZBQi3bz4q7wg2Q8YpG6wSk28omvaZaez0rwTcTtlvDaYmqgNyEMHhs79oMbvmRa7amZs+AjAVb1p8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760367575; c=relaxed/simple; bh=jvjwU3UFKyakl6j35gy5D111aTt5mZEcu5Be5l1xUss=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=kRRLIJr4abvWxP+wmPHrVtWXO3FL7kwJj9DcjwHhItsuTHYDWJlLxSPkL9rhgaDGH9wUsOQL4mOhWSAEinGLmCTadydDkd8UejFSPWD+FbeNeHmYtET6rL3eieyHV8Ot03ji6ipzqqpgKvKiDBt9ZYxcnmG+nIX/vsmmSLmYRlU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=X+rZ3Fxu; 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="X+rZ3Fxu" Received: by smtp.kernel.org (Postfix) with ESMTPSA id ABE9BC4CEFE; Mon, 13 Oct 2025 14:59:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1760367575; bh=jvjwU3UFKyakl6j35gy5D111aTt5mZEcu5Be5l1xUss=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=X+rZ3FxuE3nBUGRbbpGSXBj1s5umM2zKU8jjtc28Ifqy4Ixg0hmAtVIgzfMEeKQtE OBL24tWX4S7u+VqJNRsNrQ/M+uOPO1YFxB2QQtEBxopQ9iPgcLBmUYEfm8GTU9wTsh d4y/snXAz0Gjcf4VMn1OIXlj4wRx9H7bZztcs2m8= 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 6.6 058/196] i2c: mediatek: fix potential incorrect use of I2C_MASTER_WRRD Date: Mon, 13 Oct 2025 16:44:09 +0200 Message-ID: <20251013144317.295419980@linuxfoundation.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20251013144315.184275491@linuxfoundation.org> References: <20251013144315.184275491@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 6.6-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 1a9b5a068ef1b..6b788bca64d54 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