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/synclinkmp.c b/drivers/char/synclinkmp.c
index 26de60efe4b2..6f727e3c53ad 100644
--- a/drivers/char/synclinkmp.c
+++ b/drivers/char/synclinkmp.c
@@ -3277,13 +3277,16 @@ 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)
 {
         SLMP_INFO *info = container_of(port, SLMP_INFO, port);
         unsigned long flags;
 
         spin_lock_irqsave(&info->lock,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);
         set_signals(info);
         spin_unlock_irqrestore(&info->lock,flags);
 }
@@ -3746,7 +3749,7 @@ static void add_device(SLMP_INFO *info)
 
 static const struct tty_port_operations port_ops = {
         .carrier_raised = carrier_raised,
-        .raise_dtr_rts = raise_dtr_rts,
+        .dtr_rts = dtr_rts,
 };
 
 /* Allocate and initialize a device instance structure