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gpio: generic: support input-only chips 

Allow chips to indicates that they are input-only and thus cannot set
the output value.  This will be used by the gpio-etraxfs driver.

Signed-off-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
hifive-unleashed-5.1
Rabin Vincent 2015-07-22 15:05:18 +02:00 committed by Linus Walleij
parent 1296fba1a3
commit 91492a44b9
2 changed files with 21 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

23
drivers/gpio/gpio-generic.c
View File

@ -153,6 +153,10 @@ static int bgpio_get(struct gpio_chip *gc, unsigned int gpio)
return !!(bgc->read_reg(bgc->reg_dat) & bgc->pin2mask(bgc, gpio));
}
static void bgpio_set_none(struct gpio_chip *gc, unsigned int gpio, int val)
{
}
static void bgpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
{
struct bgpio_chip *bgc = to_bgpio_chip(gc);
@ -279,6 +283,12 @@ static int bgpio_simple_dir_in(struct gpio_chip *gc, unsigned int gpio)
return 0;
}
static int bgpio_dir_out_err(struct gpio_chip *gc, unsigned int gpio,
int val)
{
return -EINVAL;
}
static int bgpio_simple_dir_out(struct gpio_chip *gc, unsigned int gpio,
int val)
{
@ -460,6 +470,9 @@ static int bgpio_setup_io(struct bgpio_chip *bgc,
bgc->reg_set = set;
bgc->gc.set = bgpio_set_set;
bgc->gc.set_multiple = bgpio_set_multiple_set;
} else if (flags & BGPIOF_NO_OUTPUT) {
bgc->gc.set = bgpio_set_none;
bgc->gc.set_multiple = NULL;
} else {
bgc->gc.set = bgpio_set;
bgc->gc.set_multiple = bgpio_set_multiple;
@ -476,7 +489,8 @@ static int bgpio_setup_io(struct bgpio_chip *bgc,
static int bgpio_setup_direction(struct bgpio_chip *bgc,
void __iomem *dirout,
void __iomem *dirin)
void __iomem *dirin,
unsigned long flags)
{
if (dirout && dirin) {
return -EINVAL;
@ -491,7 +505,10 @@ static int bgpio_setup_direction(struct bgpio_chip *bgc,
bgc->gc.direction_input = bgpio_dir_in_inv;
bgc->gc.get_direction = bgpio_get_dir_inv;
} else {
bgc->gc.direction_output = bgpio_simple_dir_out;
if (flags & BGPIOF_NO_OUTPUT)
bgc->gc.direction_output = bgpio_dir_out_err;
else
bgc->gc.direction_output = bgpio_simple_dir_out;
bgc->gc.direction_input = bgpio_simple_dir_in;
}
@ -543,7 +560,7 @@ int bgpio_init(struct bgpio_chip *bgc, struct device *dev,
if (ret)
return ret;
ret = bgpio_setup_direction(bgc, dirout, dirin);
ret = bgpio_setup_direction(bgc, dirout, dirin, flags);
if (ret)
return ret;

1
include/linux/basic_mmio_gpio.h
View File

@ -75,5 +75,6 @@ int bgpio_init(struct bgpio_chip *bgc, struct device *dev,
#define BGPIOF_UNREADABLE_REG_DIR BIT(2) /* reg_dir is unreadable */
#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 */
#endif /* __BASIC_MMIO_GPIO_H */