[PATCH 3.18 18/32] iio: core: Return error for failed read_reg

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

3.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Matt Fornero <matt.fornero@mathworks.com>

commit 3d62c78a6eb9a7d67bace9622b66ad51e81c5f9b upstream.

If an IIO device returns an error code for a read access via debugfs, it
is currently ignored by the IIO core (other than emitting an error
message). Instead, return this error code to user space, so upper layers
can detect it correctly.

Signed-off-by: Matt Fornero <matt.fornero@mathworks.com>
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/iio/industrialio-core.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/drivers/iio/industrialio-core.c
+++ b/drivers/iio/industrialio-core.c
@@ -188,8 +188,10 @@ static ssize_t iio_debugfs_read_reg(stru
 	ret = indio_dev->info->debugfs_reg_access(indio_dev,
 						  indio_dev->cached_reg_addr,
 						  0, &val);
-	if (ret)
+	if (ret) {
 		dev_err(indio_dev->dev.parent, "%s: read failed\n", __func__);
+		return ret;
+	}
 
 	len = snprintf(buf, sizeof(buf), "0x%X\n", val);