ifneq ($(KERNELRELEASE),)
  obj-m := hello.o
else
  KERNELDIR ?= /usr/src/linux-headers-4.19.66-v7+
  PWD := $(shell pwd)

default:
	$(MAKE) -C $(KERNELDIR) M=$(PWD) modules

.PHONY: clean
clean:
	rm -rf *.o *~ core .depend .*.cmd *.ko *.mod.c .tmp_versions modules.order Module.symvers

endif