/*
 * HID driver for Nintendo Wiimote devices
 * Copyright (c) 2011 David Herrmann
 */

/*
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.
 */

#include <linux/atomic.h>
#include <linux/device.h>
#include <linux/hid.h>
#include <linux/input.h>
#include <linux/module.h>
#include "hid-ids.h"

#define WIIMOTE_VERSION "0.1"
#define WIIMOTE_NAME "Nintendo Wii Remote"

struct wiimote_data {
	atomic_t ready;
	struct hid_device *hdev;
	struct input_dev *input;
};

static int wiimote_input_event(struct input_dev *dev, unsigned int type,
						unsigned int code, int value)
{
	struct wiimote_data *wdata = input_get_drvdata(dev);

	if (!atomic_read(&wdata->ready))
		return -EBUSY;
	/* smp_rmb: Make sure wdata->xy is available when wdata->ready is 1 */
	smp_rmb();

	return 0;
}

static int wiimote_hid_event(struct hid_device *hdev, struct hid_report *report,
							u8 *raw_data, int size)
{
	struct wiimote_data *wdata = hid_get_drvdata(hdev);

	if (!atomic_read(&wdata->ready))
		return -EBUSY;
	/* smp_rmb: Make sure wdata->xy is available when wdata->ready is 1 */
	smp_rmb();

	if (size < 1)
		return -EINVAL;

	return 0;
}

static struct wiimote_data *wiimote_create(struct hid_device *hdev)
{
	struct wiimote_data *wdata;

	wdata = kzalloc(sizeof(*wdata), GFP_KERNEL);
	if (!wdata)
		return NULL;

	wdata->input = input_allocate_device();
	if (!wdata->input) {
		kfree(wdata);
		return NULL;
	}

	wdata->hdev = hdev;
	hid_set_drvdata(hdev, wdata);

	input_set_drvdata(wdata->input, wdata);
	wdata->input->event = wiimote_input_event;
	wdata->input->dev.parent = &wdata->hdev->dev;
	wdata->input->id.bustype = wdata->hdev->bus;
	wdata->input->id.vendor = wdata->hdev->vendor;
	wdata->input->id.product = wdata->hdev->product;
	wdata->input->id.version = wdata->hdev->version;
	wdata->input->name = WIIMOTE_NAME;

	return wdata;
}

static void wiimote_destroy(struct wiimote_data *wdata)
{
	kfree(wdata);
}

static int wiimote_hid_probe(struct hid_device *hdev,
				const struct hid_device_id *id)
{
	struct wiimote_data *wdata;
	int ret;

	wdata = wiimote_create(hdev);
	if (!wdata) {
		hid_err(hdev, "Can't alloc device\n");
		return -ENOMEM;
	}

	ret = hid_parse(hdev);
	if (ret) {
		hid_err(hdev, "HID parse failed\n");
		goto err;
	}

	ret = hid_hw_start(hdev, HID_CONNECT_HIDRAW);
	if (ret) {
		hid_err(hdev, "HW start failed\n");
		goto err;
	}

	ret = input_register_device(wdata->input);
	if (ret) {
		hid_err(hdev, "Cannot register input device\n");
		goto err_stop;
	}

	/* smp_wmb: Write wdata->xy first before wdata->ready is set to 1 */
	smp_wmb();
	atomic_set(&wdata->ready, 1);
	hid_info(hdev, "New device registered\n");
	return 0;

err_stop:
	hid_hw_stop(hdev);
err:
	input_free_device(wdata->input);
	wiimote_destroy(wdata);
	return ret;
}

static void wiimote_hid_remove(struct hid_device *hdev)
{
	struct wiimote_data *wdata = hid_get_drvdata(hdev);

	hid_info(hdev, "Device removed\n");
	hid_hw_stop(hdev);
	input_unregister_device(wdata->input);
	wiimote_destroy(wdata);
}

static const struct hid_device_id wiimote_hid_devices[] = {
	{ HID_BLUETOOTH_DEVICE(USB_VENDOR_ID_NINTENDO,
				USB_DEVICE_ID_NINTENDO_WIIMOTE) },
	{ }
};
MODULE_DEVICE_TABLE(hid, wiimote_hid_devices);

static struct hid_driver wiimote_hid_driver = {
	.name = "wiimote",
	.id_table = wiimote_hid_devices,
	.probe = wiimote_hid_probe,
	.remove = wiimote_hid_remove,
	.raw_event = wiimote_hid_event,
};

static int __init wiimote_init(void)
{
	int ret;

	ret = hid_register_driver(&wiimote_hid_driver);
	if (ret)
		pr_err("Can't register wiimote hid driver\n");

	return ret;
}

static void __exit wiimote_exit(void)
{
	hid_unregister_driver(&wiimote_hid_driver);
}

module_init(wiimote_init);
module_exit(wiimote_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("David Herrmann <dh.herrmann@gmail.com>");
MODULE_DESCRIPTION(WIIMOTE_NAME " Device Driver");
MODULE_VERSION(WIIMOTE_VERSION);