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Commit 8e53b0f1 authored by Alexandre Courbot's avatar Alexandre Courbot Committed by Linus Walleij
Browse files

gpio: remove const modifier from gpiod_get_direction() 



Although gpiod_get_direction() can be considered side-effect free for
consumers, its internals involve setting or clearing bits in the
affected GPIO descriptor, for which we need to force-cast the const
descriptor variable to non-const. This could lead to incorrect behavior
if the compiler decides to optimize here, so remove this const
attribute. The intent is to make gpiod_get_direction() private anyway,
so it does not really matter.

Reported-by: default avatarUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: default avatarAlexandre Courbot <acourbot@nvidia.com>
Acked-by: default avatarUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
parent 14e85c0e

drivers/gpio/gpiolib-sysfs.c

+1 −1
Original line number Diff line number Diff line
@@ -41,7 +41,7 @@ static DEFINE_MUTEX(sysfs_lock); 
static ssize_t gpio_direction_show(struct device *dev,

		struct device_attribute *attr, char *buf)

{

	const struct gpio_desc	*desc = dev_get_drvdata(dev);

	struct gpio_desc	*desc = dev_get_drvdata(dev);

	ssize_t			status;



	mutex_lock(&sysfs_lock);

drivers/gpio/gpiolib.c

+3 −5
Original line number Diff line number Diff line
@@ -148,7 +148,7 @@ static int gpiochip_find_base(int ngpio) 
 *

 * This function may sleep if gpiod_cansleep() is true.

 */

int gpiod_get_direction(const struct gpio_desc *desc)

int gpiod_get_direction(struct gpio_desc *desc)

{

	struct gpio_chip	*chip;

	unsigned		offset;
@@ -164,13 +164,11 @@ int gpiod_get_direction(const struct gpio_desc *desc) 
	if (status > 0) {

		/* GPIOF_DIR_IN, or other positive */

		status = 1;

		/* FLAG_IS_OUT is just a cache of the result of get_direction(),

		 * so it does not affect constness per se */

		clear_bit(FLAG_IS_OUT, &((struct gpio_desc *)desc)->flags);

		clear_bit(FLAG_IS_OUT, &desc->flags);

	}

	if (status == 0) {

		/* GPIOF_DIR_OUT */

		set_bit(FLAG_IS_OUT, &((struct gpio_desc *)desc)->flags);

		set_bit(FLAG_IS_OUT, &desc->flags);

	}

	return status;

}

include/linux/gpio/consumer.h

+1 −1
Original line number Diff line number Diff line
@@ -66,7 +66,7 @@ __devm_gpiod_get_index_optional(struct device *dev, const char *con_id, 
			      unsigned int index, enum gpiod_flags flags);

void devm_gpiod_put(struct device *dev, struct gpio_desc *desc);



int gpiod_get_direction(const struct gpio_desc *desc);

int gpiod_get_direction(struct gpio_desc *desc);

int gpiod_direction_input(struct gpio_desc *desc);

int gpiod_direction_output(struct gpio_desc *desc, int value);

int gpiod_direction_output_raw(struct gpio_desc *desc, int value);