tty: rework break handling

Some hardware needs to do break handling itself and may have partial
support only. Make break_ctl return an error code. Add a tty driver flag
so you can indicate driver hardware side break support.

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 5 insertions, 4 deletions

diff --git a/drivers/char/synclink_gt.c b/drivers/char/synclink_gt.c
index 2c3e43bb2cc9..cf87bb89a77d 100644
--- a/drivers/char/synclink_gt.c
+++ b/drivers/char/synclink_gt.c
@@ -165,7 +165,7 @@ static int  read_proc(char *page, char **start, off_t off, int count,int *eof, v
 static int  chars_in_buffer(struct tty_struct *tty);
 static void throttle(struct tty_struct * tty);
 static void unthrottle(struct tty_struct * tty);
-static void set_break(struct tty_struct *tty, int break_state);
+static int set_break(struct tty_struct *tty, int break_state);
 
 /*
  * generic HDLC support and callbacks
@@ -513,7 +513,7 @@ static int  wait_mgsl_event(struct slgt_info *info, int __user *mask_ptr);
 static int  tiocmget(struct tty_struct *tty, struct file *file);
 static int  tiocmset(struct tty_struct *tty, struct file *file,
                      unsigned int set, unsigned int clear);
-static void set_break(struct tty_struct *tty, int break_state);
+static int set_break(struct tty_struct *tty, int break_state);
 static int  get_interface(struct slgt_info *info, int __user *if_mode);
 static int  set_interface(struct slgt_info *info, int if_mode);
 static int  set_gpio(struct slgt_info *info, struct gpio_desc __user *gpio);
@@ -1452,14 +1452,14 @@ static void unthrottle(struct tty_struct * tty)
  * set or clear transmit break condition
  * break_state  -1=set break condition, 0=clear
  */
-static void set_break(struct tty_struct *tty, int break_state)
+static int set_break(struct tty_struct *tty, int break_state)
 {
         struct slgt_info *info = tty->driver_data;
         unsigned short value;
         unsigned long flags;
 
         if (sanity_check(info, tty->name, "set_break"))
-                return;
+                return -EINVAL;
         DBGINFO(("%s set_break(%d)\n", info->device_name, break_state));
 
         spin_lock_irqsave(&info->lock,flags);
@@ -1470,6 +1470,7 @@ static void set_break(struct tty_struct *tty, int break_state)
                 value &= ~BIT6;
         wr_reg16(info, TCR, value);
         spin_unlock_irqrestore(&info->lock,flags);
+        return 0;
 }
 
 #if SYNCLINK_GENERIC_HDLC