serial amba-pl010: enable PPS support

Function pl010_enable_ms() is automagically called when PPS ldisc
is selected.

Signed-off-by: Rodolfo Giometti <giometti@linux.it>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Greg KH <greg@kroah.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Alexander Gordeev <lasaine@lvk.cs.msu.su>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 15 insertions, 0 deletions

diff --git a/drivers/serial/amba-pl010.c b/drivers/serial/amba-pl010.c
index 429a8ae86933..e4b3c2c88bb6 100644
--- a/drivers/serial/amba-pl010.c
+++ b/drivers/serial/amba-pl010.c
@@ -471,6 +471,20 @@ pl010_set_termios(struct uart_port *port, struct ktermios *termios,
         spin_unlock_irqrestore(&uap->port.lock, flags);
 }
 
+static void pl010_set_ldisc(struct uart_port *port)
+{
+        int line = port->line;
+
+        if (line >= port->state->port.tty->driver->num)
+                return;
+
+        if (port->state->port.tty->ldisc->ops->num == N_PPS) {
+                port->flags |= UPF_HARDPPS_CD;
+                pl010_enable_ms(port);
+        } else
+                port->flags &= ~UPF_HARDPPS_CD;
+}
+
 static const char *pl010_type(struct uart_port *port)
 {
         return port->type == PORT_AMBA ? "AMBA" : NULL;
@@ -531,6 +545,7 @@ static struct uart_ops amba_pl010_pops = {
         .startup        = pl010_startup,
         .shutdown       = pl010_shutdown,
         .set_termios    = pl010_set_termios,
+        .set_ldisc      = pl010_set_ldisc,
         .type           = pl010_type,
         .release_port   = pl010_release_port,
         .request_port   = pl010_request_port,