tty: Add carrier processing on close to the tty_port core

Some drivers implement this internally, others miss it out. Push the
behaviour into the core code as that way everyone will do it consistently.

Update the dtr rts method to raise or lower depending upon flags. Having a
single method in this style fits most of the implementations more cleanly than
two funtions.

We need this in place before we tackle the USB side

Signed-off-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 6 insertions, 3 deletions

diff --git a/drivers/char/synclink.c b/drivers/char/synclink.c
index afd0b26ca056..afded3a2379c 100644
--- a/drivers/char/synclink.c
+++ b/drivers/char/synclink.c
@@ -3247,13 +3247,16 @@ static int carrier_raised(struct tty_port *port)
         return (info->serial_signals & SerialSignal_DCD) ? 1 : 0;
 }
 
-static void raise_dtr_rts(struct tty_port *port)
+static void dtr_rts(struct tty_port *port, int on)
 {
         struct mgsl_struct *info = container_of(port, struct mgsl_struct, port);
         unsigned long flags;
 
         spin_lock_irqsave(&info->irq_spinlock,flags);
-        info->serial_signals |= SerialSignal_RTS + SerialSignal_DTR;
+        if (on)
+                info->serial_signals |= SerialSignal_RTS + SerialSignal_DTR;
+        else
+                info->serial_signals &= ~(SerialSignal_RTS + SerialSignal_DTR);
         usc_set_serial_signals(info);
         spin_unlock_irqrestore(&info->irq_spinlock,flags);
 }
@@ -4258,7 +4261,7 @@ static void mgsl_add_device( struct mgsl_struct *info )
 
 static const struct tty_port_operations mgsl_port_ops = {
         .carrier_raised = carrier_raised,
-        .raise_dtr_rts = raise_dtr_rts,
+        .dtr_rts = dtr_rts,
 };