[PATCH 1/2] gpio: mpc8xxx: don't modify gpdat when setting gpio as input

[Rasmus Villemoes]

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 at prevas.dk>
---
 drivers/gpio/mpc8xxx_gpio.c | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/drivers/gpio/mpc8xxx_gpio.c b/drivers/gpio/mpc8xxx_gpio.c
index 9964d69035..5438196fe0 100644
--- 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;
 }
 
-- 
2.23.0