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gpio: provide gpiod_is_equal()

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There are users in the kernel that directly compare raw GPIO descriptor
pointers in order to determine whether they refer to the same physical
GPIO pin. This accidentally works like this but is not guaranteed by any
API contract. Let's provide a comparator function that hides the actual
logic.

Reviewed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20250407-gpiod-is-equal-v1-1-7d85f568ae6e@linaro.org
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
This commit is contained in:
Bartosz Golaszewski
2025-04-07 09:08:14 +02:00
parent 0af2f6be1b
commit 265daffe78
2 changed files with 23 additions and 0 deletions
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14
drivers/gpio/gpiolib.c
View File

@@ -265,6 +265,20 @@ struct gpio_device *gpiod_to_gpio_device(struct gpio_desc *desc)
}
EXPORT_SYMBOL_GPL(gpiod_to_gpio_device);
/**
* gpiod_is_equal() - Check if two GPIO descriptors refer to the same pin.
* @desc: Descriptor to compare.
* @other: The second descriptor to compare against.
*
* Returns:
* True if the descriptors refer to the same physical pin. False otherwise.
*/
bool gpiod_is_equal(struct gpio_desc *desc, struct gpio_desc *other)
{
return desc == other;
}
EXPORT_SYMBOL_GPL(gpiod_is_equal);
/**
* gpio_device_get_base() - Get the base GPIO number allocated by this device
* @gdev: GPIO device

9
include/linux/gpio/consumer.h
View File

@@ -180,6 +180,8 @@ struct gpio_desc *devm_fwnode_gpiod_get_index(struct device *dev,
enum gpiod_flags flags,
const char *label);
bool gpiod_is_equal(struct gpio_desc *desc, struct gpio_desc *other);
#else /* CONFIG_GPIOLIB */
#include <linux/bug.h>
@@ -547,6 +549,13 @@ struct gpio_desc *devm_fwnode_gpiod_get_index(struct device *dev,
return ERR_PTR(-ENOSYS);
}
static inline bool
gpiod_is_equal(struct gpio_desc *desc, struct gpio_desc *other)
{
WARN_ON(desc || other);
return false;
}
#endif /* CONFIG_GPIOLIB */
#if IS_ENABLED(CONFIG_GPIOLIB) && IS_ENABLED(CONFIG_HTE)