Re: [PATCH] pinctrl: armada-37xx: Add edge both type gpio irq support

[Linus Walleij]

On Tue, Oct 31, 2017 at 2:16 PM, Andrew Lunn <andrew@xxxxxxx> wrote:

>> The discussion here is interesting, it is customary for GPIO drivers
>> to implement double-edge detection emulation by swapping the
>> edge detector around like this.
>
> Hi Linus
>
> I was not aware this was customary.
>
>> It might be possible to collect some generic information about
>> this in the Documentation/gpio/driver.txt document.
>
> Yes, i think it should be documented somewhere. Even in the use case
> here, detecting an SD card being inserted/removed, you could get some
> bounce on the microswitch, miss an edge, and be in the wrong state.

Indeed :/

This is I guess why it is a good idea to combine this with the
debounce feature if the hardware supports it.

I'll think about some writeup.

Yours,
Linus Walleij