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gpiolib: Fix gpio_direction_* for single direction GPIOs

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GPIOs with no programmable direction are not required to implement
direction_output nor direction_input.

If we try to set an output direction on an output-only GPIO or input
direction on an input-only GPIO simply return 0.

This allows this single direction GPIO to be used by libgpiod.

Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This commit is contained in:
Ricardo Ribalda Delgado 2018-09-21 12:36:03 +02:00 committed by Linus Walleij
parent 32d064a16e
commit ae9847f48a
1 changed files with 28 additions and 8 deletions
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36
drivers/gpio/gpiolib.c
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@ -2543,19 +2543,27 @@ EXPORT_SYMBOL_GPL(gpiochip_free_own_desc);
int gpiod_direction_input(struct gpio_desc *desc)
{
struct gpio_chip *chip;
int status = -EINVAL;
int status = 0;
VALIDATE_DESC(desc);
chip = desc->gdev->chip;
if (!chip->get || !chip->direction_input) {
if (!chip->get && chip->direction_input) {
gpiod_warn(desc,
"%s: missing get() or direction_input() operations\n",
"%s: missing get() and direction_input() operations\n",
__func__);
return -EIO;
}
status = chip->direction_input(chip, gpio_chip_hwgpio(desc));
if (chip->direction_input) {
status = chip->direction_input(chip, gpio_chip_hwgpio(desc));
} else if (chip->get_direction &&
(chip->get_direction(chip, gpio_chip_hwgpio(desc)) != 1)) {
gpiod_warn(desc,
"%s: missing direction_input() operation\n",
__func__);
return -EIO;
}
if (status == 0)
clear_bit(FLAG_IS_OUT, &desc->flags);
@ -2577,16 +2585,28 @@ static int gpiod_direction_output_raw_commit(struct gpio_desc *desc, int value)
{
struct gpio_chip *gc = desc->gdev->chip;
int val = !!value;
int ret;
int ret = 0;
if (!gc->set || !gc->direction_output) {
if (!gc->set && !gc->direction_output) {
gpiod_warn(desc,
"%s: missing set() or direction_output() operations\n",
"%s: missing set() and direction_output() operations\n",
__func__);
return -EIO;
}
ret = gc->direction_output(gc, gpio_chip_hwgpio(desc), val);
if (gc->direction_output) {
ret = gc->direction_output(gc, gpio_chip_hwgpio(desc), val);
} else {
if (gc->get_direction &&
gc->get_direction(gc, gpio_chip_hwgpio(desc))) {
gpiod_warn(desc,
"%s: missing direction_output() operation\n",
__func__);
return -EIO;
}
gc->set(gc, gpio_chip_hwgpio(desc), val);
}
if (!ret)
set_bit(FLAG_IS_OUT, &desc->flags);
trace_gpio_value(desc_to_gpio(desc), 0, val);