From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759567AbcIWNd3 (ORCPT ); Fri, 23 Sep 2016 09:33:29 -0400 Received: from conuserg-07.nifty.com ([210.131.2.74]:49397 "EHLO conuserg-07.nifty.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754692AbcIWNd0 (ORCPT ); Fri, 23 Sep 2016 09:33:26 -0400 X-Greylist: delayed 5447 seconds by postgrey-1.27 at vger.kernel.org; Fri, 23 Sep 2016 09:33:25 EDT DKIM-Filter: OpenDKIM Filter v2.10.3 conuserg-07.nifty.com u8NDWWWb024877 X-Nifty-SrcIP: [153.142.97.92] From: Masahiro Yamada To: linux-i2c@vger.kernel.org Cc: Masahiro Yamada , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Wolfram Sang Subject: [PATCH v2] i2c: uniphier-f: fix misdetection of incomplete STOP condition Date: Fri, 23 Sep 2016 22:34:41 +0900 Message-Id: <1474637681-9589-1-git-send-email-yamada.masahiro@socionext.com> X-Mailer: git-send-email 1.9.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Currently, the status register FI2C_SR is checked immediately after a STOP condition is issued in case of the deferred STOP condition. It takes typically 5-10 usec until the corresponding bits in the register are set, so the error check for "stop condition was not completed" is very likely to be false positive. Add wait code to relax the status register check. Signed-off-by: Masahiro Yamada --- Changes in v2: - use readl_poll_timeout() drivers/i2c/busses/i2c-uniphier-f.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) diff --git a/drivers/i2c/busses/i2c-uniphier-f.c b/drivers/i2c/busses/i2c-uniphier-f.c index 829df91..db9105e 100644 --- a/drivers/i2c/busses/i2c-uniphier-f.c +++ b/drivers/i2c/busses/i2c-uniphier-f.c @@ -14,6 +14,7 @@ #include #include +#include #include #include #include @@ -348,14 +349,19 @@ static int uniphier_fi2c_master_xfer_one(struct i2c_adapter *adap, dev_dbg(&adap->dev, "complete\n"); if (unlikely(priv->flags & UNIPHIER_FI2C_DEFER_STOP_COMP)) { - u32 status = readl(priv->membase + UNIPHIER_FI2C_SR); - - if (!(status & UNIPHIER_FI2C_SR_STS) || - status & UNIPHIER_FI2C_SR_BB) { + u32 status; + int ret; + + ret = readl_poll_timeout(priv->membase + UNIPHIER_FI2C_SR, + status, + (status & UNIPHIER_FI2C_SR_STS) && + !(status & UNIPHIER_FI2C_SR_BB), + 1, 20); + if (ret) { dev_err(&adap->dev, "stop condition was not completed.\n"); uniphier_fi2c_recover(priv); - return -EBUSY; + return ret; } } -- 1.9.1