From 7e1da86339f29e445e40d41132c30741df8c19ad Mon Sep 17 00:00:00 2001
From: Arnd Bergmann <arnd@arndb.de>
Date: Mon, 25 Jan 2016 16:52:40 +0100
Subject: [PATCH] iio: ade7753: avoid uninitialized data
The ade7753_spi_read_reg_16() will either successfully read a value
from SPI, or return a failure code without delivering data. However,
the ade7753_stop_device() and ade7753_reset() functions use the returned
data without checking for an error condition first. Gcc detects this
as a possible bug and warns about it:
drivers/staging/iio/meter/ade7753.c: In function 'ade7753_remove':
drivers/staging/iio/meter/ade7753.c:348:6: error: 'val' may be used uninitialized in this function [-Werror=maybe-uninitialized]
val |= BIT(4); /* AD converters can be turned off */
^
drivers/staging/iio/meter/ade7753.c:345:6: note: 'val' was declared here
u16 val;
^
drivers/staging/iio/meter/ade7753.c: In function 'ade7753_probe':
drivers/staging/iio/meter/ade7753.c:222:6: error: 'val' may be used uninitialized in this function [-Werror=maybe-uninitialized]
In both cases, we can avoids the warning by checking the return code
before using the data.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
---
drivers/staging/iio/meter/ade7753.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/drivers/staging/iio/meter/ade7753.c b/drivers/staging/iio/meter/ade7753.c
index f129039bece3c..69287108f793b 100644
--- a/drivers/staging/iio/meter/ade7753.c
+++ b/drivers/staging/iio/meter/ade7753.c
@@ -217,8 +217,12 @@ static ssize_t ade7753_write_16bit(struct device *dev,
static int ade7753_reset(struct device *dev)
{
u16 val;
+ int ret;
+
+ ret = ade7753_spi_read_reg_16(dev, ADE7753_MODE, &val);
+ if (ret)
+ return ret;
- ade7753_spi_read_reg_16(dev, ADE7753_MODE, &val);
val |= BIT(6); /* Software Chip Reset */
return ade7753_spi_write_reg_16(dev, ADE7753_MODE, val);
@@ -343,8 +347,12 @@ static int ade7753_set_irq(struct device *dev, bool enable)
static int ade7753_stop_device(struct device *dev)
{
u16 val;
+ int ret;
+
+ ret = ade7753_spi_read_reg_16(dev, ADE7753_MODE, &val);
+ if (ret)
+ return ret;
- ade7753_spi_read_reg_16(dev, ADE7753_MODE, &val);
val |= BIT(4); /* AD converters can be turned off */
return ade7753_spi_write_reg_16(dev, ADE7753_MODE, val);
--
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