From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1768137AbcHROVj (ORCPT ); Thu, 18 Aug 2016 10:21:39 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:37574 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1767438AbcHROSE (ORCPT ); Thu, 18 Aug 2016 10:18:04 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Alim Akhtar , Krzysztof Kozlowski , Pankaj Dubey , Alexandre Belloni Subject: [PATCH 4.7 182/186] rtc: s3c: Add s3c_rtc_{enable/disable}_clk in s3c_rtc_setfreq() Date: Thu, 18 Aug 2016 15:59:59 +0200 Message-Id: <20160818135939.990568918@linuxfoundation.org> X-Mailer: git-send-email 2.9.3 In-Reply-To: <20160818135932.219369981@linuxfoundation.org> References: <20160818135932.219369981@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.7-stable review patch. If anyone has any objections, please let me know. ------------------ From: Alim Akhtar commit 70c96dfac0e231424e17743bd52f6cd2ff1f2439 upstream. As per code flow s3c_rtc_setfreq() will get called with rtc clock disabled and in set_freq we perform h/w registers read/write, which results in a kernel crash on exynos7 platform while probing rtc driver. Below is code flow: s3c_rtc_probe() clk_prepare_enable(info->rtc_clk) // rtc clock enabled s3c_rtc_gettime() // will enable clk if not done, and disable it upon exit s3c_rtc_setfreq() //then this will be called with clk disabled This patch take cares of such issue by adding s3c_rtc_{enable/disable}_clk in s3c_rtc_setfreq(). Fixes: 24e1455493da ("drivers/rtc/rtc-s3c.c: delete duplicate clock control") Signed-off-by: Alim Akhtar Reviewed-by: Krzysztof Kozlowski Reviewed-by: Pankaj Dubey Tested-by: Pankaj Dubey Signed-off-by: Alexandre Belloni Signed-off-by: Greg Kroah-Hartman --- drivers/rtc/rtc-s3c.c | 2 ++ 1 file changed, 2 insertions(+) --- a/drivers/rtc/rtc-s3c.c +++ b/drivers/rtc/rtc-s3c.c @@ -149,12 +149,14 @@ static int s3c_rtc_setfreq(struct s3c_rt if (!is_power_of_2(freq)) return -EINVAL; + s3c_rtc_enable_clk(info); spin_lock_irq(&info->pie_lock); if (info->data->set_freq) info->data->set_freq(info, freq); spin_unlock_irq(&info->pie_lock); + s3c_rtc_disable_clk(info); return 0; }