Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965350Ab3CZPXq (ORCPT ); Tue, 26 Mar 2013 11:23:46 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:54063 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965311Ab3CZPXh (ORCPT ); Tue, 26 Mar 2013 11:23:37 -0400 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Laxman Dewangan , Wolfram Sang , Luis Henriques Subject: [PATCH 115/150] i2c: tegra: check the clk_prepare_enable() return value Date: Tue, 26 Mar 2013 15:20:14 +0000 Message-Id: <1364311249-14454-116-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 1.8.1.2 In-Reply-To: <1364311249-14454-1-git-send-email-luis.henriques@canonical.com> References: <1364311249-14454-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.5 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2139 Lines: 65 3.5.7.9 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Laxman Dewangan commit 132c803f7b70b17322579f6f4f3f65cf68e55135 upstream. NVIDIA's Tegra SoC allows read/write of controller register only if controller clock is enabled. System hangs if read/write happens to registers without enabling clock. clk_prepare_enable() can be fail due to unknown reason and hence adding check for return value of this function. If this function success then only access register otherwise return to caller with error. Signed-off-by: Laxman Dewangan Reviewed-by: Stephen Warren Signed-off-by: Wolfram Sang [ luis: backport to 3.5: keep calling clk_enable ] Signed-off-by: Luis Henriques --- drivers/i2c/busses/i2c-tegra.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c index 8b2e555..12776b3 100644 --- a/drivers/i2c/busses/i2c-tegra.c +++ b/drivers/i2c/busses/i2c-tegra.c @@ -341,7 +341,11 @@ static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev) u32 val; int err = 0; - clk_enable(i2c_dev->clk); + err = clk_enable(i2c_dev->clk); + if (err < 0) { + dev_err(i2c_dev->dev, "Clock enable failed %d\n", err); + return err; + } tegra_periph_reset_assert(i2c_dev->clk); udelay(2); @@ -546,7 +550,12 @@ static int tegra_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], if (i2c_dev->is_suspended) return -EBUSY; - clk_enable(i2c_dev->clk); + ret = clk_enable(i2c_dev->clk); + if (ret < 0) { + dev_err(i2c_dev->dev, "Clock enable failed %d\n", ret); + return ret; + } + for (i = 0; i < num; i++) { int stop = (i == (num - 1)) ? 1 : 0; ret = tegra_i2c_xfer_msg(i2c_dev, &msgs[i], stop); -- 1.8.1.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/