#include <linux/module.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/slab.h>

static struct device dev_par_0;
static struct device dev_par_0_child_0;

static struct device dev_par_1;
static struct device dev_par_1_child_0;


static struct class test_class_class = {
	.name = "test_class",
};

static int create_test_devices(void)
{
	int result;

	dev_set_name(&dev_par_0, "power_zone_cpu_package_0");

	dev_par_0.class = &test_class_class;
	result = device_register(&dev_par_0);
	if (result) {
		pr_err("device_register failed for parent_0\n");
		return result;
	}
	
	dev_set_name(&dev_par_1, "power_zone_cpu_package_1");
	dev_par_1.class = &test_class_class;
	result = device_register(&dev_par_1);
	if (result) {
		pr_err("device_register failed for parent_0\n");		
		goto error_par1;
	}
	

	dev_set_name(&dev_par_0_child_0, "power-zone-cpu-0");
	dev_par_0_child_0.class = &test_class_class;
	dev_par_0_child_0.parent = &dev_par_0;
	result = device_register(&dev_par_0_child_0);
	if (result) {
		pr_err("device_register failed for dev_par_0_child_0\n");		
		goto error_par0_child_0;
	}

	dev_set_name(&dev_par_1_child_0, "power-zone-cpu-0");
	dev_par_1_child_0.class = &test_class_class;
	dev_par_1_child_0.parent = &dev_par_1;
	result = device_register(&dev_par_1_child_0);
	if (result) {
		pr_err("device_register failed for dev_par_1_child_0\n");		
		goto error_par0_child_1;
	}

	return 0;

error_par0_child_1:
	device_unregister(&dev_par_0_child_0);
error_par0_child_0:
	device_unregister(&dev_par_1);
error_par1:
	device_unregister(&dev_par_0);

	return result;
}




static int __init dev_create_test_init(void)
{
	int result = 0;

	pr_debug("dev_create_test_init\n");
	result = class_register(&test_class_class);
	if (result)
		return result;

	result = create_test_devices();

	return result;
}

static void dev_create_test_exit(void)
{
	pr_debug("dev_create_test_exit\n");

	device_unregister(&dev_par_0_child_0);
	device_unregister(&dev_par_1_child_0);	
	device_unregister(&dev_par_0);
	device_unregister(&dev_par_1);

	class_unregister(&test_class_class);
}


module_init(dev_create_test_init)
module_exit(dev_create_test_exit)
MODULE_LICENSE("GPL v2");