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

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Date:   Wed, 25 Apr 2018 13:06:42 -0500
From:   Grygorii Strashko <grygorii.strashko@...com>
To:     Florian Fainelli <f.fainelli@...il.com>,
        <linux-kernel@...r.kernel.org>, <linux-gpio@...r.kernel.org>,
        <devicetree@...r.kernel.org>, <dmitry.torokhov@...il.com>,
        <jeffy.chen@...k-chips.com>, <enric.balletbo@...labora.com>,
        <josephl@...dia.com>, <opendmb@...il.com>, <rjw@...ysocki.net>
Subject: Re: Lack of suspend/resume/shutdown ordering between GPIO providers
 and consumers



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?



-- 
regards,
-grygorii