diff --git a/drivers/net/ieee802154/ca8210.c b/drivers/net/ieee802154/ca8210.c
index bf837adfebb2..01af4f9cf7f2 100644
--- a/drivers/net/ieee802154/ca8210.c
+++ b/drivers/net/ieee802154/ca8210.c
@@ -595,7 +595,7 @@ static int ca8210_test_int_driver_write(
 	fifo_buffer = kmemdup(buf, len, GFP_KERNEL);
 	if (!fifo_buffer)
 		return -ENOMEM;
-	kfifo_in(&test->up_fifo, &fifo_buffer, 4);
+	kfifo_in(&test->up_fifo, &fifo_buffer, sizeof(fifo_buffer));
 	wake_up_interruptible(&priv->test.readq);
 
 	return 0;
@@ -2526,6 +2526,7 @@ static ssize_t ca8210_test_int_user_read(
 	struct ca8210_priv *priv = filp->private_data;
 	unsigned char *fifo_buffer;
 	unsigned long bytes_not_copied;
+	unsigned int copied;
 
 	if (filp->f_flags & O_NONBLOCK) {
 		/* Non-blocking mode */
@@ -2539,7 +2540,8 @@ static ssize_t ca8210_test_int_user_read(
 		);
 	}
 
-	if (kfifo_out(&priv->test.up_fifo, &fifo_buffer, 4) != 4) {
+	copied = kfifo_out(&priv->test.up_fifo, &fifo_buffer, sizeof(fifo_buffer));
+	if (copied != sizeof(fifo_buffer)) {
 		dev_err(
 			&priv->spi->dev,
 			"test_interface: Wrong number of elements popped from upstream fifo\n"