Commit ae9847f4 authored by Ricardo Ribalda Delgado's avatar Ricardo Ribalda Delgado Committed by Linus Walleij
Browse files

gpiolib: Fix gpio_direction_* for single direction GPIOs 



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: default avatarRicardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
parent 32d064a1

drivers/gpio/gpiolib.c

+28 −8
Original line number Diff line number Diff line
@@ -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;

	}



	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;

	}



	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);

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