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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Miaoqian Lin <linmq006@gmail.com>,
        Philippe Schenker <philippe.schenker@toradex.com>,
        Jonathan Cameron <Jonathan.Cameron@huawei.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.15 028/247] iio: adc: stmpe-adc: Fix wait_for_completion_timeout return value check
Date:   Mon, 13 Jun 2022 12:08:50 +0200
Message-Id: <20220613094923.789535183@linuxfoundation.org>
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From: Miaoqian Lin <linmq006@gmail.com>

[ Upstream commit d345b23200bcdbd2bd3582213d738c258b77718f ]

wait_for_completion_timeout() returns unsigned long not long.
it returns 0 if timed out, and positive if completed.
The check for <= 0 is ambiguous and should be == 0 here
indicating timeout which is the only error case

Fixes: e813dde6f833 ("iio: stmpe-adc: Use wait_for_completion_timeout")
Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
Reviewed-by: Philippe Schenker <philippe.schenker@toradex.com>
Link: https://lore.kernel.org/r/20220412065150.14486-1-linmq006@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/iio/adc/stmpe-adc.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/iio/adc/stmpe-adc.c b/drivers/iio/adc/stmpe-adc.c
index fba659bfdb40..64305d9fa560 100644
--- a/drivers/iio/adc/stmpe-adc.c
+++ b/drivers/iio/adc/stmpe-adc.c
@@ -61,7 +61,7 @@ struct stmpe_adc {
 static int stmpe_read_voltage(struct stmpe_adc *info,
 		struct iio_chan_spec const *chan, int *val)
 {
-	long ret;
+	unsigned long ret;
 
 	mutex_lock(&info->lock);
 
@@ -79,7 +79,7 @@ static int stmpe_read_voltage(struct stmpe_adc *info,
 
 	ret = wait_for_completion_timeout(&info->completion, STMPE_ADC_TIMEOUT);
 
-	if (ret <= 0) {
+	if (ret == 0) {
 		stmpe_reg_write(info->stmpe, STMPE_REG_ADC_INT_STA,
 				STMPE_ADC_CH(info->channel));
 		mutex_unlock(&info->lock);
@@ -96,7 +96,7 @@ static int stmpe_read_voltage(struct stmpe_adc *info,
 static int stmpe_read_temp(struct stmpe_adc *info,
 		struct iio_chan_spec const *chan, int *val)
 {
-	long ret;
+	unsigned long ret;
 
 	mutex_lock(&info->lock);
 
@@ -114,7 +114,7 @@ static int stmpe_read_temp(struct stmpe_adc *info,
 
 	ret = wait_for_completion_timeout(&info->completion, STMPE_ADC_TIMEOUT);
 
-	if (ret <= 0) {
+	if (ret == 0) {
 		mutex_unlock(&info->lock);
 		return -ETIMEDOUT;
 	}
-- 
2.35.1