FEATURES_REQUIRED += periph_gpio
FEATURES_REQUIRED += periph_i2c

_PCF857X_IRQ_MODULE := $(filter pcf857x_irq_%,$(USEMODULE))
ifneq (,$(_PCF857X_IRQ_MODULE))
  # pull in the correspondant event_thread_<priority> module
  USEMODULE += $(_PCF857X_IRQ_MODULE:pcf857x_irq_%=event_thread_%)
  USEMODULE += pcf857x_irq
else
  ifneq (,$(filter pcf857x_irq,$(USEMODULE)))
    # pull in the pcf857x_irq_medium module as default if pcf857x_irq is used.
    USEMODULE += pcf857x_irq_medium
  endif
endif

ifneq (,$(filter pcf857x_irq,$(USEMODULE)))
  FEATURES_REQUIRED += periph_gpio_irq
  USEMODULE += pcf857x
endif