From patchwork Tue Jan 28 11:10:30 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Rasmus Villemoes X-Patchwork-Id: 240403 List-Id: U-Boot discussion From: rasmus.villemoes at prevas.dk (Rasmus Villemoes) Date: Tue, 28 Jan 2020 11:10:30 +0000 Subject: [PATCH 1/2] gpio: mpc8xxx: don't modify gpdat when setting gpio as input In-Reply-To: <20200128111020.15136-1-rasmus.villemoes@prevas.dk> References: <20200128111020.15136-1-rasmus.villemoes@prevas.dk> Message-ID: <20200128111020.15136-2-rasmus.villemoes@prevas.dk> 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 --- 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; }