From mboxrd@z Thu Jan 1 00:00:00 1970 From: Grygorii Strashko Subject: Re: Lack of suspend/resume/shutdown ordering between GPIO providers and consumers Date: Wed, 25 Apr 2018 13:47:22 -0500 Message-ID: References: <03711276-d854-7f87-f2e2-c64716b09dbe@ti.com> <206bea0c-dbba-1bc3-d13b-dbc41d12c08b@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <206bea0c-dbba-1bc3-d13b-dbc41d12c08b@gmail.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Florian Fainelli , linux-kernel@vger.kernel.org, linux-gpio@vger.kernel.org, devicetree@vger.kernel.org, dmitry.torokhov@gmail.com, jeffy.chen@rock-chips.com, enric.balletbo@collabora.com, josephl@nvidia.com, opendmb@gmail.com, rjw@rjwysocki.net List-Id: devicetree@vger.kernel.org On 04/25/2018 01:29 PM, Florian Fainelli wrote: > On 04/25/2018 11:06 AM, Grygorii Strashko wrote: >> >> >> 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. > > OK, though that requires a struct device references, so while I could > certainly resolve the device_node -> struct device that corresponds to > the GPIO provider , that poses a number of issues: > > - not all struct device_node have a corresponding struct device > reference (e.g: clock providers, interrupt controllers, and possibly > other custom drivers), though in this case, they most likely do have one > > - resolving a struct device associated with a struct device_node is > often done in a "bus" specific way, e.g: of_find_device_by_node(), so if > the GPIO provider is e.g: i2c_device, pci_device etc. etc. this might > not work that easily > > I think this is what Dmitry just indicated in his email as well. > >> >> 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? > > The issue exists with shutdown (through the use of "poweroff"), that is > confirmed, but I cannot see how it does not exist with any suspend state > as well, for the same reason that the ordering is not strictly enforced. Sry, but it still required some clarification :( - poweroff calls device_shutdown() which, in turn, should not call .suspend(), so how have you got both .shutdown() and .suspend() callbacks called during poweroff? Am I missing smth? Note. Suspend and shutdown uses different dev lists: - shutdown uses kset - suspend uses dpm_list -- regards, -grygorii