serial: Test/disable MSIs if switching from N_PPS

Switching to the N_PPS line discipline may require enabling
modem status interrupts; conversely switching from N_PPS may
require disabling modem status interrupts.

Affected drivers:
8250
amba-pl010
atmel

Cc: Nicolas Ferre <nicolas.ferre@atmel.com>
Cc: Russell King <linux@arm.linux.org.uk>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c
index f0f35e7..25eb8e9 100644 (file)
--- a/drivers/tty/serial/8250/8250_core.c
+++ b/drivers/tty/serial/8250/8250_core.c
@@ -1402,6 +1402,19 @@ static void serial8250_stop_rx(struct uart_port *port)
        serial8250_rpm_put(up);
 }
 
+static void serial8250_disable_ms(struct uart_port *port)
+{
+       struct uart_8250_port *up =
+               container_of(port, struct uart_8250_port, port);
+
+       /* no MSR capabilities */
+       if (up->bugs & UART_BUG_NOMSR)
+               return;
+
+       up->ier &= ~UART_IER_MSI;
+       serial_port_out(port, UART_IER, up->ier);
+}
+
 static void serial8250_enable_ms(struct uart_port *port)
 {
        struct uart_8250_port *up = up_to_u8250p(port);
@@ -2616,8 +2629,14 @@ serial8250_set_ldisc(struct uart_port *port, struct ktermios *termios)
                spin_lock_irq(&port->lock);
                serial8250_enable_ms(port);
                spin_unlock_irq(&port->lock);
-       } else
+       } else {
                port->flags &= ~UPF_HARDPPS_CD;
+               if (!UART_ENABLE_MS(port, termios->c_cflag)) {
+                       spin_lock_irq(&port->lock);
+                       serial8250_disable_ms(port);
+                       spin_unlock_irq(&port->lock);
+               }
+       }
 }
 
 

diff --cc drivers/tty/serial/amba-pl010.c
Simple merge

diff --cc drivers/tty/serial/atmel_serial.c
Simple merge