Re: which driver to choose for a GPIO connected switch

Alexander Stein [off-list ref] writes:

I'm just wondering which existing input driver I can choose to use an GPIO 
connected switch. The switch I'm talking about is connected via 3 
(interruptable) GPIOs and those GPIOs can be inverted.

Hi,

How is the switch connected to the three GPIO inputs?

I think gpio-keys is wrong as they will generate events on each state change.
Note: The switch is likely to bounce

The gpio-keys driver has debouncing support.

and the current GPIO state might be invalid (all 3 GPIOs are 0).

Why is this state invalid?

I also think gpio-keys can't make sure only one switch state is currently 
present. So I may get a current state 1 on 2 or more GPIOs which is obviously 
wrong.

Sorry, I don't understand this.

My use case is the userspace polls the current switch state if it needs to 
know.

EVIOCGKEY or EVIOCGSW ioctl, perhaps?  You can make it three keys or
switches in the driver, and put the validation logic into user space...

Do you have any suggestions which driver to use or even write?

Maybe it's just me, but I think you'd better give a clearer description
of your problem to get useful suggestions.
-- 
Regards,
Feri.