From 03842c17397e14cb8bb1adc2015f5dce6c733ffe Mon Sep 17 00:00:00 2001 From: Francois Berder Date: Tue, 25 Oct 2016 13:24:13 +0100 Subject: [PATCH] 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 Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/sc16is7xx.c | 8 ++++++-- 1 file 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));