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Commit be1a4b13 authored by Linus Walleij's avatar Linus Walleij
Browse files

gpio: improve error path in gpiolib 



At several places the gpiolib will proceed to handle a GPIO
descriptor even if it's ->chip member is NULL and no gpiochip
is associated.

Fix this by checking that both the descriptor cookie *and*
the chip pointer are valid.

Also bail out earlier with more specific diagnostic messages
on missing operations for setting as input/output or debounce.

ChangeLog v1->v2:
- Also return -EIO on gpiod_set_debounce() with missing
  operations in the vtable
- Fix indentations.

Suggested-by: default avatarAlexandre Courbot <acourbot@nvidia.com>
Acked-by: default avatarAlexandre Courbot <acourbot@nvidia.com>
Reviewed-by: default avatarFrank Rowand <frank.rowand@sonymobile.com>
Cc: Tim Bird <tim.bird@sonymobile.com>
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
parent 6c17aa01

drivers/gpio/gpiolib.c

+25 −16
Original line number Diff line number Diff line
@@ -1398,7 +1398,7 @@ static int gpiod_request(struct gpio_desc *desc, const char *label) 
	int			status = -EPROBE_DEFER;

	unsigned long		flags;



	if (!desc) {

	if (!desc || !desc->chip) {

		pr_warn("%s: invalid GPIO\n", __func__);

		return -EINVAL;

	}
@@ -1406,8 +1406,6 @@ static int gpiod_request(struct gpio_desc *desc, const char *label) 
	spin_lock_irqsave(&gpio_lock, flags);



	chip = desc->chip;

	if (chip == NULL)

		goto done;



	if (!try_module_get(chip->owner))

		goto done;
@@ -1630,16 +1628,20 @@ static int gpiod_direction_input(struct gpio_desc *desc) 
	int			status = -EINVAL;

	int			offset;



	if (!desc) {

	if (!desc || !desc->chip) {

		pr_warn("%s: invalid GPIO\n", __func__);

		return -EINVAL;

	}



	chip = desc->chip;

	if (!chip->get || !chip->direction_input) {

		pr_warn("%s: missing get() or direction_input() operations\n",

			__func__);

		return -EIO;

	}



	spin_lock_irqsave(&gpio_lock, flags);



	chip = desc->chip;

	if (!chip || !chip->get || !chip->direction_input)

		goto fail;

	status = gpio_ensure_requested(desc);

	if (status < 0)

		goto fail;
@@ -1691,7 +1693,7 @@ static int gpiod_direction_output(struct gpio_desc *desc, int value) 
	int			status = -EINVAL;

	int offset;



	if (!desc) {

	if (!desc || !desc->chip) {

		pr_warn("%s: invalid GPIO\n", __func__);

		return -EINVAL;

	}
@@ -1704,11 +1706,15 @@ static int gpiod_direction_output(struct gpio_desc *desc, int value) 
	if (!value && test_bit(FLAG_OPEN_SOURCE,  &desc->flags))

		return gpiod_direction_input(desc);



	chip = desc->chip;

	if (!chip->set || !chip->direction_output) {

		pr_warn("%s: missing set() or direction_output() operations\n",

			__func__);

		return -EIO;

	}



	spin_lock_irqsave(&gpio_lock, flags);



	chip = desc->chip;

	if (!chip || !chip->set || !chip->direction_output)

		goto fail;

	status = gpio_ensure_requested(desc);

	if (status < 0)

		goto fail;
@@ -1765,16 +1771,19 @@ static int gpiod_set_debounce(struct gpio_desc *desc, unsigned debounce) 
	int			status = -EINVAL;

	int			offset;



	if (!desc) {

	if (!desc || !desc->chip) {

		pr_warn("%s: invalid GPIO\n", __func__);

		return -EINVAL;

	}



	spin_lock_irqsave(&gpio_lock, flags);



	chip = desc->chip;

	if (!chip || !chip->set || !chip->set_debounce)

		goto fail;

	if (!chip->set || !chip->set_debounce) {

		pr_warn("%s: missing set() or set_debounce() operations\n",

			__func__);

		return -EIO;

	}



	spin_lock_irqsave(&gpio_lock, flags);



	status = gpio_ensure_requested(desc);

	if (status < 0)