From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759136AbaCTPMo (ORCPT ); Thu, 20 Mar 2014 11:12:44 -0400 Received: from mail-pd0-f182.google.com ([209.85.192.182]:49943 "EHLO mail-pd0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754030AbaCTPMm (ORCPT ); Thu, 20 Mar 2014 11:12:42 -0400 From: Guenter Roeck To: linux-kernel@vger.kernel.org Cc: Samuel Ortiz , Lee Jones , Michael Brunner , Guenter Roeck Subject: [PATCH] mfd: kempld-core: Fix potential hang-up during boot Date: Thu, 20 Mar 2014 08:12:28 -0700 Message-Id: <1395328348-20661-1-git-send-email-linux@roeck-us.net> X-Mailer: git-send-email 1.7.9.7 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On PXT and COMe-cPC2 boards it is observed that the hardware mutex is acquired but not being released during initialization. This can result in a hang-up during boot if the driver is built into the kernel. Releasing the mutex twice if it was acquired fixes the problem. Subsequent request/release cycles work as expected, so the fix is only needed during initialization. Reviewed-by: Michael Brunner Tested-by: Michael Brunner Signed-off-by: Guenter Roeck --- drivers/mfd/kempld-core.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/drivers/mfd/kempld-core.c b/drivers/mfd/kempld-core.c index d3e2327..38917a8 100644 --- a/drivers/mfd/kempld-core.c +++ b/drivers/mfd/kempld-core.c @@ -322,9 +322,12 @@ static int kempld_detect_device(struct kempld_device_data *pld) return -ENODEV; } - /* Release hardware mutex if aquired */ - if (!(index_reg & KEMPLD_MUTEX_KEY)) + /* Release hardware mutex if acquired */ + if (!(index_reg & KEMPLD_MUTEX_KEY)) { iowrite8(KEMPLD_MUTEX_KEY, pld->io_index); + /* PXT and COMe-cPC2 boards may require a second release */ + iowrite8(KEMPLD_MUTEX_KEY, pld->io_index); + } mutex_unlock(&pld->lock); -- 1.7.9.7