On Wednesday, April 25, 2018 9:29:59 PM CEST Grygorii Strashko wrote: > > On 04/25/2018 02:10 PM, Grygorii Strashko wrote: > > > > > > On 04/25/2018 01:57 PM, Florian Fainelli wrote: > >> On 04/25/2018 11:47 AM, Grygorii Strashko wrote: > >>> > >>> > >>> 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? > >> > >> You are missing me telling you the whole story, sorry I got confused, > >> but you are absolutely right these are separate lists and on > >> poweroff/shutdown only ->shutdown() is called. What I had missed in the > >> report I was submitted was that there was a .shutdown() callback being > >> added to gpio_keys.c, which of course, because it's an Android based > >> project is not in the upstream Linux kernel. > >> > >> The problem does remain valid though AFAICT. Thanks Grygorii! > >> > > > > Thanks. But that means you should not see this problem :( > > There is devices_kset_move_last() call in really_probe() which moves probed dev > > at the end of kset, and gpio_keys should never be probed before gpio-brcmstb because > > both devm_fwnode_get_gpiod_from_child() and devm_gpio_request_one() expected to return > > -EPROBE_DEFER otherwise. > > > > Theoretically issue still might happen with suspend. > > > > FYI https://lkml.org/lkml/2015/9/10/218 And also https://patchwork.kernel.org/patch/10334661/ -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
