drivers/misc/icr/icr-core.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright 2020 Google LLC.
 */

#include <linux/idr.h>
#include <linux/module.h>
#include <linux/slab.h>

#include "icr-core.h"

static struct class *icr_class;
static DEFINE_IDA(icr_instance_ida);

static ssize_t open_show(struct device *dev,
			 struct device_attribute *attr, char *buf)
{
	struct icr_data *data = dev_get_drvdata(dev);

	return data->ops->open_show(dev->parent, attr, buf);
}

static ssize_t open_store(struct device *dev,
			  struct device_attribute *attr, const char *buf, size_t count)
{
	struct icr_data *data = dev_get_drvdata(dev);

	return data->ops->open_store(dev->parent, attr, buf, count);
}

static DEVICE_ATTR_RW(open);
static struct attribute *icr_attrs[] = {
	&dev_attr_open.attr,
	NULL
};
ATTRIBUTE_GROUPS(icr);

struct device *icr_core_register(struct device *dev, const struct icr_ops *ops)
{
	struct device *new_dev;
	struct icr_data *icr_data;
	int ret;

	icr_data = kmalloc(sizeof(*icr_data), GFP_KERNEL);
	if (!icr_data) {
		ret = -ENOMEM;
		goto out;
	}

	icr_data->id = ida_simple_get(&icr_instance_ida, 0, 0, GFP_KERNEL);
	if (icr_data->id < 0) {
		pr_err("Failed to allocate id\n");
		ret = icr_data->id;
		goto out_free_icr_data;
	}

	icr_data->ops = ops;

	new_dev = device_create_with_groups(icr_class, dev, 0, icr_data, icr_groups, "icr%d",
					    icr_data->id);
	if (IS_ERR(new_dev)) {
		ret = PTR_ERR(new_dev);
		goto out_free_id;
	}

	return new_dev;

out_free_id:
	ida_simple_remove(&icr_instance_ida, icr_data->id);
out_free_icr_data:
	kfree(icr_data);
out:
	return ERR_PTR(ret);
}
EXPORT_SYMBOL_GPL(icr_core_register);

void icr_core_unregister(struct device *icr_dev)
{
	struct icr_data *data = dev_get_drvdata(icr_dev);

	ida_simple_remove(&icr_instance_ida, data->id);
	device_unregister(icr_dev);
	kfree(data);
}
EXPORT_SYMBOL_GPL(icr_core_unregister);

int __init icr_core_init(void)
{
	icr_class = class_create(THIS_MODULE, "icr");
	if (IS_ERR(icr_class)) {
		pr_err("Failed to create icr class\n");
		return PTR_ERR(icr_class);
	}

	return 0;
}

void __exit icr_core_exit(void)
{
	class_destroy(icr_class);
	icr_class = NULL;
}

MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("ICR core module");
module_init(icr_core_init);
module_exit(icr_core_exit);