On 09/07/2017 02:51 PM, woojung....@microchip.com wrote: >>>>> If someone is using GPIO descriptors with GPIO disabled, i.e. calling >>>>> gpiod_get() and friends, this is very likely to be a bug, and what >>>>> the driver wants to do is: >>>>> >>>>> depends on GPIOLIB >>>>> >>>>> or >>>>> >>>>> select GPIOLIB >>>>> >>>>> in Kconfig. The whole optional thing is mainly a leftover from when it >>>>> was possible to have a local implementation of the GPIOLIB API in >>>>> some custom header file, noone sane should be doing that anymore, >>>>> and if they do, they can very well face the warnings. >>>>> >>>>> If someone is facing a lot of WARN_ON() messages to this, it is a clear >>>>> indication that they need to fix their Kconfig and in that case it is >>>>> proper. >>>> Linus & Andrew, >>>> >>>> I knew that it is already in David's pulling request. >>>> Configuring GPIOLIB is the right solution even if platform doesn't use it? >>> >>> I guess? >>> >>> "Platform doesn't use it" what does that mean? >>> >>> Does it mean it does not call the >>> APIs of the GPIOLIB, does it mean it doesn't have a GPIO driver >>> at probe (but may have one by having it probed from a module) >>> or does it mean the platform can never have it? >> >> I think it means CONFIG_GPIOLIB=n in the kernel because it's not needed, >> yet you run code (like drivers/net/phy/mdio_bus.c) that unconditionally >> calls into GPIOLIB and attempts to configure a given GPIO if available. > Yes. I'm facing issue on PC which won't need GPIOLIB as default. > Warning message goes away when GPIOLIB is enabled, and fortunately, > Ubuntu default config has it. > So, it may not be seen by many users when with full/default configuration.
Woojung, I suppose you are also getting a warning from gpiod_set_value_cansleep() done in mdiobus_unregister() right? With CONFIG_GPIOLIB=n devm_gpiod_get_optional() returns NULL, which we don't check as an error, on purpose however we still call gpiod_set_value_cansleep() on a NULL GPIO descriptor, so the following should do: diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c index b6f9fa670168..67dbb7c26840 100644 --- a/drivers/net/phy/mdio_bus.c +++ b/drivers/net/phy/mdio_bus.c @@ -424,7 +424,8 @@ void mdiobus_unregister(struct mii_bus *bus) } /* Put PHYs in RESET to save power */ - gpiod_set_value_cansleep(bus->reset_gpiod, 1); + if (!IS_ERR_OR_NULL(bus->reset_gpiod)) + gpiod_set_value_cansleep(bus->reset_gpiod, 1); device_del(&bus->dev); } > >> This thread is actually what prompted me to write this email: >> >> https://lkml.org/lkml/2017/9/2/3 > Thanks for the link. > > -- Florian