sc16is7xx: don't wipe out port configuration on shutdown

EFCR register contains RS-485 configuration which should not
be changed by shutdown.  Instead of doing a write only update
the appropriate bits.

Signed-off-by: Jakub Kicinski <kubakici@wp.pl>
Signed-off-by: Jon Ringle <jringle@gridpoint.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 5 insertions, 3 deletions

diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c
index 11bb44039a57..e6b396e584f3 100644
--- a/drivers/tty/serial/sc16is7xx.c
+++ b/drivers/tty/serial/sc16is7xx.c
@@ -903,9 +903,11 @@ static void sc16is7xx_shutdown(struct uart_port *port)
         /* Disable all interrupts */
         sc16is7xx_port_write(port, SC16IS7XX_IER_REG, 0);
         /* Disable TX/RX */
-        sc16is7xx_port_write(port, SC16IS7XX_EFCR_REG,
-                             SC16IS7XX_EFCR_RXDISABLE_BIT |
-                             SC16IS7XX_EFCR_TXDISABLE_BIT);
+        sc16is7xx_port_update(port, SC16IS7XX_EFCR_REG,
+                              SC16IS7XX_EFCR_RXDISABLE_BIT |
+                              SC16IS7XX_EFCR_TXDISABLE_BIT,
+                              SC16IS7XX_EFCR_RXDISABLE_BIT |
+                              SC16IS7XX_EFCR_TXDISABLE_BIT);
 
         sc16is7xx_power(port, 0);
 }