gpio: mpc8xxx: don't modify gpdat when setting gpio as input

Since some chips don't support reading back the value of output gpios
from the gpdat register, we should not do a RMW cycle (i.e., the
clrbits_be32) on the gpdat register when setting a gpio as input, as
that might accidentally change the value of some other (still
configured as output) gpio.

The extra indirection through mpc8xxx_gpio_set_in() does not help
readability, so just fold the gpdir update into
mpc8xxx_gpio_direction_input().

Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk>

diff --git a/drivers/gpio/mpc8xxx_gpio.c b/drivers/gpio/mpc8xxx_gpio.c
index c273c2c8a40d0866bc7d56f9d3f7087ad64c3b6e..d4f3092df0739eda0790448402fb20bf122eb3c6 100644 (file)
--- a/drivers/gpio/mpc8xxx_gpio.c
+++ b/drivers/gpio/mpc8xxx_gpio.c
@@ -57,13 +57,6 @@ static inline u32 mpc8xxx_gpio_get_dir(struct ccsr_gpio *base, u32 mask)
        return in_be32(&base->gpdir) & mask;
 }
 
-static inline void mpc8xxx_gpio_set_in(struct ccsr_gpio *base, u32 gpios)
-{
-       clrbits_be32(&base->gpdat, gpios);
-       /* GPDIR register 0 -> input */
-       clrbits_be32(&base->gpdir, gpios);
-}
-
 static inline void mpc8xxx_gpio_set_low(struct ccsr_gpio *base, u32 gpios)
 {
        clrbits_be32(&base->gpdat, gpios);
@@ -100,8 +93,11 @@ static inline void mpc8xxx_gpio_open_drain_off(struct ccsr_gpio *base,
 static int mpc8xxx_gpio_direction_input(struct udevice *dev, uint gpio)
 {
        struct mpc8xxx_gpio_data *data = dev_get_priv(dev);
+       u32 mask = gpio_mask(gpio);
+
+       /* GPDIR register 0 -> input */
+       clrbits_be32(&data->base->gpdir, mask);
 
-       mpc8xxx_gpio_set_in(data->base, gpio_mask(gpio));
        return 0;
 }