[PATCH 2/2] iio: buffer: Return error if no callback is given

[Nuno Sá <nuno.sa@xxxxxxxxxx>]

Return error in case no callback is provided to
`iio_channel_get_all_cb()`. There's no point in setting up a buffer-cb
if no callback is provided.

Signed-off-by: Nuno Sá <nuno.sa@xxxxxxxxxx>
---
 drivers/iio/buffer/industrialio-buffer-cb.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/iio/buffer/industrialio-buffer-cb.c b/drivers/iio/buffer/industrialio-buffer-cb.c
index 47c96f7f4976..4c12b7a94af5 100644
--- a/drivers/iio/buffer/industrialio-buffer-cb.c
+++ b/drivers/iio/buffer/industrialio-buffer-cb.c
@@ -54,6 +54,11 @@ struct iio_cb_buffer *iio_channel_get_all_cb(struct device *dev,
 	struct iio_cb_buffer *cb_buff;
 	struct iio_channel *chan;
 
+	if (!cb) {
+		dev_err(dev, "Invalid arguments: A callback must be provided!\n");
+		return ERR_PTR(-EINVAL);
+	}
+
 	cb_buff = kzalloc(sizeof(*cb_buff), GFP_KERNEL);
 	if (cb_buff == NULL)
 		return ERR_PTR(-ENOMEM);
-- 
2.17.1