Hello all,
It appears there is some inconsistency among implementations of the
`hal_gpio_irq_enable()` function. There are two behaviors associated
with this function:
(1) Enable the interrupt associated with the specified pin.
(2) Clear any pending interrupt associated with the specified pin.
All implementations perform (1); only some perform (2).
This email concerns the second item - should `hal_gpio_irq_enable()`
also clear the pending interrupt?
I can understand why it is useful for the function to perform both
actions. Often, when some code temporarily disables an interrupt, it
wants to ensure that an interrupt triggered in the meantime does not
cause its ISR to be executed. Since there is no HAL function to clear
interrupt state, the enable function is the natural place to implement
this behavior.
On the other hand, it could argued that a function which does both
things is too coarse an abstraction. An application may want to perform
just one of the two actions.
In my view, there are two possible solutions:
1. Just make the behavior consistent: make all implementations of
`hal_gpio_irq_enable()` perform both actions.
2. Add some functions to the HAL:
a. Make all implementations of `hal_gpio_irq_enable()` only perform
the first action.
b. Add `void hal_gpio_irq_clear(int pin)`
c. Add `void hal_gpio_irq_set(int pin)`
(or combine b and c into a single function.)
Option 2 introduces more of a backwards compatibility headache than 1
does. Still, I think it is the better solution.
All comments welcome.
Thanks,
Chris
