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by queseuq
Sat May 12, 2018 7:51 pm
Forum: Device Tree
Topic: Two drivers using same gpio pin
Replies: 10
Views: 2580

Re: Two drivers using same gpio pin

For anyone interested in this, I found that I could export the pin directly from the kernel driver. I can then (hopefully) use a userspace daemon to monitor it's state. I've opened a pull request (https://github.com/raspberrypi/linux/pull/2552) to add this functionality upstream.
by queseuq
Thu Mar 22, 2018 12:11 pm
Forum: Device Tree
Topic: Two drivers using same gpio pin
Replies: 10
Views: 2580

Re: Two drivers using same gpio pin

I suppose one could minimise the duplication of effort by getting the gpio-poweroff driver to advertise itself as a tiny gpio controller, sharing its own gpio as if it were a different gpio. This sounds interesting but a bit beyond me unfortunately. I presume I'd have to do something more that just...
by queseuq
Thu Mar 22, 2018 10:58 am
Forum: Device Tree
Topic: Two drivers using same gpio pin
Replies: 10
Views: 2580

Re: Two drivers using same gpio pin

Thanks for the reply, I thought that might be the case but want to check just in case. Assuming you could share the pin at the software level, how were you going to arrange that pushing the switch doesn't trigger a premature power-off? Are you really that short of pins to warrant the complexity? I'm...
by queseuq
Tue Mar 20, 2018 11:14 pm
Forum: Device Tree
Topic: Two drivers using same gpio pin
Replies: 10
Views: 2580

Two drivers using same gpio pin

I've been digging around the kernel a bit to see if I can work this out but I thought it would be quicker to post the question here. Basically I want to combine the gpio-poweroff-overlay and gpio-shutdown-overlay into a single overlay that does both tasks on the same pin. This seems feasible in theo...

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