tty: Make tiocgicount a handler

Dan Rosenberg noted that various drivers return the struct with uncleared
fields. Instead of spending forever trying to stomp all the drivers that
get it wrong (and every new driver) do the job in one place.

This first patch adds the needed operations and hooks them up, including
the needed USB midlayer and serial core plumbing.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

2 files changed, 11 insertions, 0 deletions

diff --git a/include/linux/tty_driver.h b/include/linux/tty_driver.h
index b08677982525..db2d227694da 100644
--- a/include/linux/tty_driver.h
+++ b/include/linux/tty_driver.h
@@ -224,6 +224,12 @@
  *      unless the tty also has a valid tty->termiox pointer.
  *
  *      Optional: Called under the termios lock
+ *
+ * int (*get_icount)(struct tty_struct *tty, struct serial_icounter *icount);
+ *
+ *      Called when the device receives a TIOCGICOUNT ioctl. Passed a kernel
+ *      structure to complete. This method is optional and will only be called
+ *      if provided (otherwise EINVAL will be returned).
  */
 
 #include <linux/fs.h>
@@ -232,6 +238,7 @@
 
 struct tty_struct;
 struct tty_driver;
+struct serial_icounter_struct;
 
 struct tty_operations {
         struct tty_struct * (*lookup)(struct tty_driver *driver,
@@ -268,6 +275,8 @@ struct tty_operations {
                         unsigned int set, unsigned int clear);
         int (*resize)(struct tty_struct *tty, struct winsize *ws);
         int (*set_termiox)(struct tty_struct *tty, struct termiox *tnew);
+        int (*get_icount)(struct tty_struct *tty,
+                                struct serial_icounter_struct *icount);
 #ifdef CONFIG_CONSOLE_POLL
         int (*poll_init)(struct tty_driver *driver, int line, char *options);
         int (*poll_get_char)(struct tty_driver *driver, int line);
diff --git a/include/linux/usb/serial.h b/include/linux/usb/serial.h
index 55675b1efb28..16d682f4f7c3 100644
--- a/include/linux/usb/serial.h
+++ b/include/linux/usb/serial.h
@@ -271,6 +271,8 @@ struct usb_serial_driver {
         int  (*tiocmget)(struct tty_struct *tty, struct file *file);
         int  (*tiocmset)(struct tty_struct *tty, struct file *file,
                          unsigned int set, unsigned int clear);
+        int  (*get_icount)(struct tty_struct *tty,
+                        struct serial_icounter_struct *icount);
         /* Called by the tty layer for port level work. There may or may not
            be an attached tty at this point */
         void (*dtr_rts)(struct usb_serial_port *port, int on);