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gpio: mmio: introduce BGPIOF_NO_SET_ON_INPUT

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Some gpio controllers ignores pin value writing when that pin is
configured as input mode. As a result, bgpio_dir_out should set
pin to output before configuring pin values or gpio pin values
can't be set up properly.
Introduce two variants of bgpio_dir_out: bgpio_dir_out_val_first
and bgpio_dir_out_dir_first, and assign direction_output according
to a new flag: BGPIOF_NO_SET_ON_INPUT.

Signed-off-by: Chuanhong Guo <gch981213@gmail.com>
Tested-by: René van Dorst <opensource@vdorst.com>
Reviewed-by: Sergio Paracuellos <sergio.paracuellos@gmail.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
This commit is contained in:
Chuanhong Guo 2020-03-15 20:13:37 +08:00 committed by Bartosz Golaszewski
parent d1ee7e1f5c
commit d19d2de61f
2 changed files with 20 additions and 4 deletions
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23
drivers/gpio/gpio-mmio.c
View file

@ -389,12 +389,10 @@ static int bgpio_get_dir(struct gpio_chip *gc, unsigned int gpio)
return GPIO_LINE_DIRECTION_IN;
}
static int bgpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
static void bgpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
{
unsigned long flags;
gc->set(gc, gpio, val);
spin_lock_irqsave(&gc->bgpio_lock, flags);
gc->bgpio_dir |= bgpio_line2mask(gc, gpio);
@ -405,7 +403,21 @@ static int bgpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
gc->write_reg(gc->reg_dir_out, gc->bgpio_dir);
spin_unlock_irqrestore(&gc->bgpio_lock, flags);
}
static int bgpio_dir_out_dir_first(struct gpio_chip *gc, unsigned int gpio,
int val)
{
bgpio_dir_out(gc, gpio, val);
gc->set(gc, gpio, val);
return 0;
}
static int bgpio_dir_out_val_first(struct gpio_chip *gc, unsigned int gpio,
int val)
{
gc->set(gc, gpio, val);
bgpio_dir_out(gc, gpio, val);
return 0;
}
@ -538,7 +550,10 @@ static int bgpio_setup_direction(struct gpio_chip *gc,
if (dirout || dirin) {
gc->reg_dir_out = dirout;
gc->reg_dir_in = dirin;
gc->direction_output = bgpio_dir_out;
if (flags & BGPIOF_NO_SET_ON_INPUT)
gc->direction_output = bgpio_dir_out_dir_first;
else
gc->direction_output = bgpio_dir_out_val_first;
gc->direction_input = bgpio_dir_in;
gc->get_direction = bgpio_get_dir;
} else {

1
include/linux/gpio/driver.h
View file

@ -572,6 +572,7 @@ int bgpio_init(struct gpio_chip *gc, struct device *dev,
#define BGPIOF_BIG_ENDIAN_BYTE_ORDER BIT(3)
#define BGPIOF_READ_OUTPUT_REG_SET BIT(4) /* reg_set stores output value */
#define BGPIOF_NO_OUTPUT BIT(5) /* only input */
#define BGPIOF_NO_SET_ON_INPUT BIT(6)
int gpiochip_irq_map(struct irq_domain *d, unsigned int irq,
irq_hw_number_t hwirq);