TTY: add support for unnumbered device nodes

This allows drivers like ttyprintk to avoid hacks to create an
unnumbered node in /dev. It used to set TTY_DRIVER_DYNAMIC_DEV in
flags and call device_create on its own. That is incorrect, because
TTY_DRIVER_DYNAMIC_DEV may be set only if tty_register_device is
called explicitly.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 6 insertions, 0 deletions

diff --git a/include/linux/tty_driver.h b/include/linux/tty_driver.h
index 1a85f003d646..44e05b75d573 100644
--- a/include/linux/tty_driver.h
+++ b/include/linux/tty_driver.h
@@ -394,6 +394,11 @@ static inline struct tty_driver *tty_driver_kref_get(struct tty_driver *d)
  * TTY_DRIVER_DYNAMIC_ALLOC -- do not allocate structures which are
  *      needed per line for this driver as it would waste memory.
  *      The driver will take care.
+ *
+ * TTY_DRIVER_UNNUMBERED_NODE -- do not create numbered /dev nodes. In
+ *      other words create /dev/ttyprintk and not /dev/ttyprintk0.
+ *      Applicable only when a driver for a single tty device is
+ *      being allocated.
  */
 #define TTY_DRIVER_INSTALLED            0x0001
 #define TTY_DRIVER_RESET_TERMIOS        0x0002
@@ -402,6 +407,7 @@ static inline struct tty_driver *tty_driver_kref_get(struct tty_driver *d)
 #define TTY_DRIVER_DEVPTS_MEM           0x0010
 #define TTY_DRIVER_HARDWARE_BREAK       0x0020
 #define TTY_DRIVER_DYNAMIC_ALLOC        0x0040
+#define TTY_DRIVER_UNNUMBERED_NODE      0x0080
 
 /* tty driver types */
 #define TTY_DRIVER_TYPE_SYSTEM          0x0001