sc16is7xx: always write state when configuring GPIO as an output

The regmap_update first reads the IOState register and then triggers
a write if needed. However, GPIOS might be configured as an input so
 the read to IOState on this GPIO is the current state which might
be random.

Signed-off-by: Francois Berder <Francois.Berder@imgtec.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 6 insertions, 2 deletions

diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c
index 2675792a8f59..fb0672554123 100644
--- a/drivers/tty/serial/sc16is7xx.c
+++ b/drivers/tty/serial/sc16is7xx.c
@@ -1130,9 +1130,13 @@ static int sc16is7xx_gpio_direction_output(struct gpio_chip *chip,
 {
         struct sc16is7xx_port *s = gpiochip_get_data(chip);
         struct uart_port *port = &s->p[0].port;
+        u8 state = sc16is7xx_port_read(port, SC16IS7XX_IOSTATE_REG);
 
-        sc16is7xx_port_update(port, SC16IS7XX_IOSTATE_REG, BIT(offset),
-                              val ? BIT(offset) : 0);
+        if (val)
+                state |= BIT(offset);
+        else
+                state &= ~BIT(offset);
+        sc16is7xx_port_write(port, SC16IS7XX_IOSTATE_REG, state);
         sc16is7xx_port_update(port, SC16IS7XX_IODIR_REG, BIT(offset),
                               BIT(offset));