Since JOYSTICK_SENSEHAT selects MFD_SIMPLE_MFD_I2C and the latter depends on HAS_IOMEM, and since 'select' does not follow any dependency chains, JOYSTICK_SENSEHAT should also depend on HAS_IOMEM to prevent a kconfig warning and a build error: WARNING: unmet direct dependencies detected for MFD_SIMPLE_MFD_I2C Depends on [n]: HAS_IOMEM [=n] && I2C [=y] Selected by [y]: - JOYSTICK_SENSEHAT [=y] && INPUT_JOYSTICK [=y] && INPUT [=y] && I2C [=y] s390-linux-ld: drivers/mfd/simple-mfd-i2c.o: in function `simple_mfd_i2c_probe': simple-mfd-i2c.c:(.text+0xc8): undefined reference to `devm_mfd_add_devices' Fixes: 41657514c796 ("Input: add Raspberry Pi Sense HAT joystick driver") Signed-off-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx> Cc: Charles Mirabile <cmirabil@xxxxxxxxxx> Cc: Daniel Bauman <dbauman@xxxxxxxxxx> Cc: Mwesigwa Guma <mguma@xxxxxxxxxx> Cc: Joel Savitz <jsavitz@xxxxxxxxxx> Cc: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx> Cc: linux-input@xxxxxxxxxxxxxxx --- drivers/input/joystick/Kconfig | 1 + 1 file changed, 1 insertion(+) --- a/drivers/input/joystick/Kconfig +++ b/drivers/input/joystick/Kconfig @@ -402,6 +402,7 @@ config JOYSTICK_N64 config JOYSTICK_SENSEHAT tristate "Raspberry Pi Sense HAT joystick" depends on INPUT && I2C + depends on HAS_IOMEM select MFD_SIMPLE_MFD_I2C help Say Y here if you want to enable the driver for the