#include <linux/cdev.h>
#include <linux/init.h>
#include <linux/module.h>

#include "fopdrv.h"
#include "config.h"

struct cdev *cdev;
struct device *dev;
struct class *class;
dev_t node;
struct file_operations fops = {
	.read = fop_read,
	.write = fop_write,
	.open = fop_open,
	.release = fop_release,
};

static int mod_init(void) {
	int err;

	err = alloc_chrdev_region(&node, 0, 1, DRV_NAME);
	if (err < 0) {
		printk(KERN_ERR "alloc_chrdev_region error %d\n", err);
		goto return_err;
	}

	class = class_create(DRV_NAME);
	if (IS_ERR_OR_NULL(class)) {
		err = PTR_ERR(class);
		printk(KERN_ERR "class_create error %d\n", err);
		goto free_class;
	}

	cdev = cdev_alloc();
	if (!cdev) {
		err = ENOMEM;
		goto free_cdev;
	}

	cdev->ops = &fops;
	cdev_init(cdev, &fops);
	err = cdev_add(cdev, node, 1);
	if (err < 0) {
		printk(KERN_ERR "cdev_add error %d\n", err);
		goto free_cdev;
	}

	dev = device_create(class, NULL, node, NULL, DRV_NAME);
	if (IS_ERR_OR_NULL(dev)) {
		err = PTR_ERR(dev);
		printk(KERN_ERR "device_create error %d\n", err);
		goto free_device;
	}

	printk("%s() -> 0 (%d:%d)\n", __PRETTY_FUNCTION__, MAJOR(node), MINOR(node));
	return 0;

free_device:
	device_destroy(class, node);
free_cdev:
	cdev_del(cdev);
free_class:
	class_destroy(class);
return_err:
	printk("%s() -> %d\n", __PRETTY_FUNCTION__, err);
	return err;
}

static void mod_exit(void) {
	device_destroy(class, node);
	cdev_del(cdev);
	class_destroy(class);
	printk("%s()\n", __PRETTY_FUNCTION__);
}

module_init(mod_init);
module_exit(mod_exit);
MODULE_LICENSE("Dual MIT/GPL");