caif: check write operations
write is optional for a tty device. Check that we have a write op rather
than calling NULL.
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/caif/caif_serial.c b/drivers/net/caif/caif_serial.c
index 3502f60..c669ec3 100644
--- a/drivers/net/caif/caif_serial.c
+++ b/drivers/net/caif/caif_serial.c
@@ -312,6 +312,10 @@
char name[64];
int result;
+ /* No write no play */
+ if (tty->ops->write == NULL)
+ return -EOPNOTSUPP;
+
sprintf(name, "cf%s", tty->name);
dev = alloc_netdev(sizeof(*ser), name, caifdev_setup);
ser = netdev_priv(dev);