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drivers/gpio: document that unsupported DEBOUNCE should be ignored

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A large number of sensor drivers specify GPIO_INT_DEBOUNCE to request
a debounced signal; in practice the debounce may be performed by
external components on the board.  Historically this flag was ignored
on the many GPIO peripherals that do not support hardware debouncing.

Document that this flag is an exception to the normal rule that
unsupported features should be rejected by gpio_pin_configure.

Signed-off-by: Peter Bigot <peter.bigot@nordicsemi.no>
This commit is contained in:
Peter Bigot 2019-10-08 11:50:45 -05:00 • committed by Carles Cufí
commit fca26890b0
1 changed files with 9 additions and 3 deletions
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12
include/drivers/gpio.h
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@ -182,7 +182,11 @@ extern "C" {
/** @} */
/** Enable GPIO pin debounce. */
/** Enable GPIO pin debounce.
*
* @note Drivers that do not support a debounce feature should ignore
* this flag rather than rejecting the configuration with -ENOTSUP.
*/
#define GPIO_INT_DEBOUNCE (1U << 17)
/**
@ -583,7 +587,8 @@ static inline int z_impl_gpio_disable_callback(struct device *port,
* @param flags Interrupt configuration flags as defined by GPIO_INT_*.
*
* @retval 0 If successful.
* @retval -ENOTSUP If any of the configuration options is not supported.
* @retval -ENOTSUP If any of the configuration options is not supported
* (unless otherwise directed by flag documentation).
* @retval -EINVAL Invalid argument.
* @retval -EBUSY Interrupt line required to configure pin interrupt is
* already in use.
@ -632,7 +637,8 @@ static inline int z_impl_gpio_pin_interrupt_configure(struct device *port,
* bias flags', GPIO_INT_DEBOUNCE.
*
* @retval 0 If successful.
* @retval -ENOTSUP if any of the configuration options is not supported.
* @retval -ENOTSUP if any of the configuration options is not supported
* (unless otherwise directed by flag documentation).
* @retval -EINVAL Invalid argument.
* @retval -EIO I/O error when accessing an external GPIO chip.
* @retval -EWOULDBLOCK if operation would block.