1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Vibration support for Mega World controllers
4 *
5 * Copyright 2022 Frank Zago
6 *
7 * Derived from hid-zpff.c:
8 *   Copyright (c) 2005, 2006 Anssi Hannula <anssi.hannula@gmail.com>
9 */
10
11#include <linux/hid.h>
12#include <linux/input.h>
13#include <linux/module.h>
14#include <linux/slab.h>
15
16#include "hid-ids.h"
17
18struct mwctrl_device {
19	struct hid_report *report;
20	s32 *weak;
21	s32 *strong;
22};
23
24static int mwctrl_play(struct input_dev *dev, void *data,
25		       struct ff_effect *effect)
26{
27	struct hid_device *hid = input_get_drvdata(dev);
28	struct mwctrl_device *mwctrl = data;
29
30	*mwctrl->strong = effect->u.rumble.strong_magnitude >> 8;
31	*mwctrl->weak = effect->u.rumble.weak_magnitude >> 8;
32
33	hid_hw_request(hid, mwctrl->report, HID_REQ_SET_REPORT);
34
35	return 0;
36}
37
38static int mwctrl_init(struct hid_device *hid)
39{
40	struct mwctrl_device *mwctrl;
41	struct hid_report *report;
42	struct hid_input *hidinput;
43	struct input_dev *dev;
44	int error;
45	int i;
46
47	if (list_empty(&hid->inputs)) {
48		hid_err(hid, "no inputs found\n");
49		return -ENODEV;
50	}
51	hidinput = list_entry(hid->inputs.next, struct hid_input, list);
52	dev = hidinput->input;
53
54	for (i = 0; i < 4; i++) {
55		report = hid_validate_values(hid, HID_OUTPUT_REPORT, 0, i, 1);
56		if (!report)
57			return -ENODEV;
58	}
59
60	mwctrl = kzalloc(sizeof(struct mwctrl_device), GFP_KERNEL);
61	if (!mwctrl)
62		return -ENOMEM;
63
64	set_bit(FF_RUMBLE, dev->ffbit);
65
66	error = input_ff_create_memless(dev, mwctrl, mwctrl_play);
67	if (error) {
68		kfree(mwctrl);
69		return error;
70	}
71
72	mwctrl->report = report;
73
74	/* Field 0 is always 2, and field 1 is always 0. The original
75	 * windows driver has a 5 bytes command, where the 5th byte is
76	 * a repeat of the 3rd byte, however the device has only 4
77	 * fields. It could be a bug in the driver, or there is a
78	 * different device that needs it.
79	 */
80	report->field[0]->value[0] = 0x02;
81
82	mwctrl->strong = &report->field[2]->value[0];
83	mwctrl->weak = &report->field[3]->value[0];
84
85	return 0;
86}
87
88static int mwctrl_probe(struct hid_device *hdev, const struct hid_device_id *id)
89{
90	int ret;
91
92	ret = hid_parse(hdev);
93	if (ret) {
94		hid_err(hdev, "parse failed\n");
95		return ret;
96	}
97
98	ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT & ~HID_CONNECT_FF);
99	if (ret) {
100		hid_err(hdev, "hw start failed\n");
101		return ret;
102	}
103
104	ret = mwctrl_init(hdev);
105	if (ret)
106		hid_hw_stop(hdev);
107
108	return ret;
109}
110
111static const struct hid_device_id mwctrl_devices[] = {
112	{ HID_USB_DEVICE(USB_VENDOR_MEGAWORLD,
113			 USB_DEVICE_ID_MEGAWORLD_GAMEPAD) },
114	{ }
115};
116MODULE_DEVICE_TABLE(hid, mwctrl_devices);
117
118static struct hid_driver mwctrl_driver = {
119	.name = "megaworld",
120	.id_table = mwctrl_devices,
121	.probe = mwctrl_probe,
122};
123module_hid_driver(mwctrl_driver);
124
125MODULE_LICENSE("GPL");
126