c - objs in Makefile breaks kernel module

Question

I'm trying to write a kernel module for a display but I'm struggling with the basics. If I try to separate source files and define this in Makefile via -objs, the kernel module gets compiled, load, but doesnt do anything.

Code:

driver.c

#define LINUX
#include <linux/module.h> 
#include <linux/kernel.h>
#include "display.h"

int init_module(void) {
    printk(KERN_INFO "module registered\n");
    init_display();
    return 0;
}

void cleanup_module(void) {
     printk(KERN_INFO "module unregistered\n");
}

display.h

#ifndef DISPLAY_H
#define DISPLAY_H
void init_display (void);
#endif

display.c

#include "display.h"
#include <linux/module.h>  /* Needed by all modules */
#include <linux/kernel.h>  /* Needed for KERN_ALERT */

void init_display (void) {
    printk(KERN_INFO "initialize display\n");
}

Makefile

obj-m := driver.o
driver-objs := driver.o display.o
KDIR := /lib/modules/$(shell uname -r)/build
PWD := $(shell pwd)

default:
    $(MAKE) -C $(KDIR) SUBDIRS=$(PWD) modules
clean:
    $(MAKE) -C $(KDIR) SUBDIRS=$(PWD) clean

Without the include and driver-objs in Makefile I'm getting the KERN_INFO (load, unload) output, with it, the kernellog is empty.

Any directions, what I'm doing wrong?