staging:iio: prevent divide by zero bugs

"val" is used as a divisor later, so we should check for zero here to
avoid a division by zero.
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Acked-by: NLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

drivers/staging/iio/adc/ad7192.c

@@ -647,6 +647,8 @@ static ssize_t ad7192_write_frequency(struct device *dev,
 	ret = strict_strtoul(buf, 10, &lval);
 	if (ret)
 		return ret;
+	if (lval == 0)
+		return -EINVAL;
 
 	mutex_lock(&indio_dev->mlock);
 	if (iio_buffer_enabled(indio_dev)) {

drivers/staging/iio/gyro/adis16260_core.c

@@ -195,6 +195,8 @@ static ssize_t adis16260_write_frequency(struct device *dev,
 	ret = strict_strtol(buf, 10, &val);
 	if (ret)
 		return ret;
+	if (val == 0)
+		return -EINVAL;
 
 	mutex_lock(&indio_dev->mlock);
 	if (spi_get_device_id(st->us)) {

drivers/staging/iio/imu/adis16400_core.c

@@ -234,6 +234,8 @@ static ssize_t adis16400_write_frequency(struct device *dev,
 	ret = strict_strtol(buf, 10, &val);
 	if (ret)
 		return ret;
+	if (val == 0)
+		return -EINVAL;
 
 	mutex_lock(&indio_dev->mlock);
 

drivers/staging/iio/meter/ade7753.c

@@ -425,6 +425,8 @@ static ssize_t ade7753_write_frequency(struct device *dev,
 	ret = strict_strtol(buf, 10, &val);
 	if (ret)
 		return ret;
+	if (val == 0)
+		return -EINVAL;
 
 	mutex_lock(&indio_dev->mlock);
 

drivers/staging/iio/meter/ade7754.c

@@ -445,6 +445,8 @@ static ssize_t ade7754_write_frequency(struct device *dev,
 	ret = strict_strtol(buf, 10, &val);
 	if (ret)
 		return ret;
+	if (val == 0)
+		return -EINVAL;
 
 	mutex_lock(&indio_dev->mlock);
 

drivers/staging/iio/meter/ade7759.c

@@ -385,6 +385,8 @@ static ssize_t ade7759_write_frequency(struct device *dev,
 	ret = strict_strtol(buf, 10, &val);
 	if (ret)
 		return ret;
+	if (val == 0)
+		return -EINVAL;
 
 	mutex_lock(&indio_dev->mlock);