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Date: Wed, 11 Jun 2014 11:13:17 +0300
From: Dan Carpenter <dan.carpenter@oracle.com>
To: Jonathan Cameron <jic23@kernel.org>
Cc: Grant Likely <grant.likely@linaro.org>,
	Rob Herring <robh+dt@kernel.org>, Josh Wu <josh.wu@atmel.com>,
	Alexandre Belloni <alexandre.belloni@free-electrons.com>,
	Nicolas Ferre <nicolas.ferre@atmel.com>,
	Maxime Ripard <maxime.ripard@free-electrons.com>,
	Lars-Peter Clausen <lars@metafoo.de>,
	Thomas Meyer <thomas@m3y3r.de>,
	Wei Yongjun <yongjun_wei@trendmicro.com.cn>,
	Sachin Kamat <sachin.kamat@linaro.org>,
	linux-iio@vger.kernel.org, kernel-janitors@vger.kernel.org
Subject: [patch v2] iio: adc: at91: signedness bug in
 at91_adc_get_trigger_value_by_name()
Message-ID: <20140611081317.GA29444@mwanda>
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In-Reply-To: <53980711.5030604@bfs.de>
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List-Id: linux-iio@vger.kernel.org

at91_adc_get_trigger_value_by_name() was returning -ENOMEM truncated to
a positive u8 and that doesn't work.  I've changed it to int and
refactored it to preserve the error code.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
I'm not able to compile this code.

v2:  Preserve the -ENOMEM

diff --git a/drivers/iio/adc/at91_adc.c b/drivers/iio/adc/at91_adc.c
index 3b5bacd..2b6a9ce 100644
--- a/drivers/iio/adc/at91_adc.c
+++ b/drivers/iio/adc/at91_adc.c
@@ -510,12 +510,11 @@ static int at91_adc_channel_init(struct iio_dev *idev)
 	return idev->num_channels;
 }
 
-static u8 at91_adc_get_trigger_value_by_name(struct iio_dev *idev,
+static int at91_adc_get_trigger_value_by_name(struct iio_dev *idev,
 					     struct at91_adc_trigger *triggers,
 					     const char *trigger_name)
 {
 	struct at91_adc_state *st = iio_priv(idev);
-	u8 value = 0;
 	int i;
 
 	for (i = 0; i < st->trigger_number; i++) {
@@ -528,15 +527,16 @@ static u8 at91_adc_get_trigger_value_by_name(struct iio_dev *idev,
 			return -ENOMEM;
 
 		if (strcmp(trigger_name, name) == 0) {
-			value = triggers[i].value;
 			kfree(name);
-			break;
+			if (triggers[i].value == 0)
+				return -EINVAL;
+			return triggers[i].value;
 		}
 
 		kfree(name);
 	}
 
-	return value;
+	return -EINVAL;
 }
 
 static int at91_adc_configure_trigger(struct iio_trigger *trig, bool state)
@@ -546,14 +546,14 @@ static int at91_adc_configure_trigger(struct iio_trigger *trig, bool state)
 	struct iio_buffer *buffer = idev->buffer;
 	struct at91_adc_reg_desc *reg = st->registers;
 	u32 status = at91_adc_readl(st, reg->trigger_register);
-	u8 value;
+	int value;
 	u8 bit;
 
 	value = at91_adc_get_trigger_value_by_name(idev,
 						   st->trigger_list,
 						   idev->trig->name);
-	if (value == 0)
-		return -EINVAL;
+	if (value < 0)
+		return value;
 
 	if (state) {
 		st->buffer = kmalloc(idev->scan_bytes, GFP_KERNEL);