[PATCH] sc16is7xx: always write state when configuring GPIO as an, output

[Francois Berder <francois.berder@xxxxxxxxxx>]

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@xxxxxxxxxx>
---
 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 f36e6df..546c913 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));
 
-- 
2.6.2

>From e4d5c43f6bd950e65bb36974a4d8cf38a77bca5b Mon Sep 17 00:00:00 2001
From: Francois Berder <Francois.Berder@xxxxxxxxxx>
Date: Thu, 30 Jun 2016 18:26:33 +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 <Francois.Berder@xxxxxxxxxx>
---
 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 f36e6df..546c913 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));
 
-- 
2.6.2