gpio: sch311x: Use RMW to change direction
Bit 0 in the config register obviously controls the direction
of the GPIO so instead of hammering 0x0/0x1 into that register,
use read-modify-write so that we can also alter the other bits
in the register.
Cc: Bruno Randolf <br1@einfach.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/gpio/gpio-sch311x.c b/drivers/gpio/gpio-sch311x.c
index ed64f7f..faf4417 100644
--- a/drivers/gpio/gpio-sch311x.c
+++ b/drivers/gpio/gpio-sch311x.c
@@ -23,10 +23,9 @@
#define DRV_NAME "gpio-sch311x"
-#define SCH311X_GPIO_CONF_OUT 0x00
-#define SCH311X_GPIO_CONF_IN 0x01
-#define SCH311X_GPIO_CONF_INVERT 0x02
-#define SCH311X_GPIO_CONF_OPEN_DRAIN 0x80
+#define SCH311X_GPIO_CONF_DIR BIT(0)
+#define SCH311X_GPIO_CONF_INVERT BIT(1)
+#define SCH311X_GPIO_CONF_OPEN_DRAIN BIT(7)
#define SIO_CONFIG_KEY_ENTER 0x55
#define SIO_CONFIG_KEY_EXIT 0xaa
@@ -196,10 +195,12 @@ static void sch311x_gpio_set(struct gpio_chip *chip, unsigned offset,
static int sch311x_gpio_direction_in(struct gpio_chip *chip, unsigned offset)
{
struct sch311x_gpio_block *block = gpiochip_get_data(chip);
+ unsigned char data;
spin_lock(&block->lock);
- outb(SCH311X_GPIO_CONF_IN, block->runtime_reg +
- block->config_regs[offset]);
+ data = inb(block->runtime_reg + block->config_regs[offset]);
+ data |= SCH311X_GPIO_CONF_DIR;
+ outb(data, block->runtime_reg + block->config_regs[offset]);
spin_unlock(&block->lock);
return 0;
@@ -209,12 +210,13 @@ static int sch311x_gpio_direction_out(struct gpio_chip *chip, unsigned offset,
int value)
{
struct sch311x_gpio_block *block = gpiochip_get_data(chip);
+ unsigned char data;
spin_lock(&block->lock);
- outb(SCH311X_GPIO_CONF_OUT, block->runtime_reg +
- block->config_regs[offset]);
-
+ data = inb(block->runtime_reg + block->config_regs[offset]);
+ data &= ~SCH311X_GPIO_CONF_DIR;
+ outb(data, block->runtime_reg + block->config_regs[offset]);
__sch311x_gpio_set(block, offset, value);
spin_unlock(&block->lock);
@@ -230,7 +232,7 @@ static int sch311x_gpio_get_direction(struct gpio_chip *chip, unsigned offset)
data = inb(block->runtime_reg + block->config_regs[offset]);
spin_unlock(&block->lock);
- return !!(data & SCH311X_GPIO_CONF_IN);
+ return !!(data & SCH311X_GPIO_CONF_DIR);
}
static int sch311x_gpio_probe(struct platform_device *pdev)