Re: Lack of suspend/resume/shutdown ordering between GPIO providers and consumers

From: Grygorii Strashko
Date: Wed Apr 25 2018 - 14:07:08 EST

On 04/24/2018 05:58 PM, Florian Fainelli wrote:
Hi Linus, Rafael, all

Our GPIO controller driver: gpio-brcmstb.c has a shutdown callback which
gets invoked when the system is brought into poweroff aka S5. So far so
good, except that we also wish to use gpio_keys.c as a possible wake-up
source, so we may have a number of GPIO pins declared as gpio-keys that
allow the system to wake-up from deep slumber.

Recently we noticed that we could easily get into a state where
gpio-brcmstb.c::brcmstb_gpio_shutdown() gets called first, and then
gpio_keys.c::gpio_keys_suspend() gets called later, which is too late to
have the enable_irq_wake() call do anything sensible since we have
suspend its parent interrupt controller before. This is completely
expected unfortunately because these two drivers are both platform
device instances with no connection to one another except via Device
Tree and the use of the GPIOLIB APIs.

You can take a look at device_link_add() and Co.

But it's little bit unclear what exactly you have issue with:
- shutdown
- suspend

above are different (at least as it was before) and gpio-brcmstb.c
brcmstb_gpio_shutdown() should not be called as part of suspend !?
may be you mean brcmstb_gpio_suspend?