iio: core: Return error for failed read_reg

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>

diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
index 17ec4cee51dc005a9f7cc0efc92a9326a3906a61..a47428b4d31be9b07adc5cfb96dd9c0472397006 100644 (file)
--- a/drivers/iio/industrialio-core.c
+++ b/drivers/iio/industrialio-core.c
@@ -310,8 +310,10 @@ static ssize_t iio_debugfs_read_reg(struct file *file, char __user *userbuf,
        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);