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>

diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c
index 2675792..fb06725 100644 (file)
--- 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));