1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Stadia controller rumble support.
4 *
5 * Copyright 2023 Google LLC
6 */
7
8#include <linux/hid.h>
9#include <linux/input.h>
10#include <linux/slab.h>
11#include <linux/module.h>
12
13#include "hid-ids.h"
14
15#define STADIA_FF_REPORT_ID 5
16
17struct stadiaff_device {
18	struct hid_device *hid;
19	struct hid_report *report;
20	spinlock_t lock;
21	bool removed;
22	uint16_t strong_magnitude;
23	uint16_t weak_magnitude;
24	struct work_struct work;
25};
26
27static void stadiaff_work(struct work_struct *work)
28{
29	struct stadiaff_device *stadiaff =
30		container_of(work, struct stadiaff_device, work);
31	struct hid_field *rumble_field = stadiaff->report->field[0];
32	unsigned long flags;
33
34	spin_lock_irqsave(&stadiaff->lock, flags);
35	rumble_field->value[0] = stadiaff->strong_magnitude;
36	rumble_field->value[1] = stadiaff->weak_magnitude;
37	spin_unlock_irqrestore(&stadiaff->lock, flags);
38
39	hid_hw_request(stadiaff->hid, stadiaff->report, HID_REQ_SET_REPORT);
40}
41
42static int stadiaff_play(struct input_dev *dev, void *data,
43			 struct ff_effect *effect)
44{
45	struct hid_device *hid = input_get_drvdata(dev);
46	struct stadiaff_device *stadiaff = hid_get_drvdata(hid);
47	unsigned long flags;
48
49	spin_lock_irqsave(&stadiaff->lock, flags);
50	if (!stadiaff->removed) {
51		stadiaff->strong_magnitude = effect->u.rumble.strong_magnitude;
52		stadiaff->weak_magnitude = effect->u.rumble.weak_magnitude;
53		schedule_work(&stadiaff->work);
54	}
55	spin_unlock_irqrestore(&stadiaff->lock, flags);
56
57	return 0;
58}
59
60static int stadiaff_init(struct hid_device *hid)
61{
62	struct stadiaff_device *stadiaff;
63	struct hid_report *report;
64	struct hid_input *hidinput;
65	struct input_dev *dev;
66	int error;
67
68	if (list_empty(&hid->inputs)) {
69		hid_err(hid, "no inputs found\n");
70		return -ENODEV;
71	}
72	hidinput = list_entry(hid->inputs.next, struct hid_input, list);
73	dev = hidinput->input;
74
75	report = hid_validate_values(hid, HID_OUTPUT_REPORT,
76				     STADIA_FF_REPORT_ID, 0, 2);
77	if (!report)
78		return -ENODEV;
79
80	stadiaff = devm_kzalloc(&hid->dev, sizeof(struct stadiaff_device),
81				GFP_KERNEL);
82	if (!stadiaff)
83		return -ENOMEM;
84
85	hid_set_drvdata(hid, stadiaff);
86
87	input_set_capability(dev, EV_FF, FF_RUMBLE);
88
89	error = input_ff_create_memless(dev, NULL, stadiaff_play);
90	if (error)
91		return error;
92
93	stadiaff->removed = false;
94	stadiaff->hid = hid;
95	stadiaff->report = report;
96	INIT_WORK(&stadiaff->work, stadiaff_work);
97	spin_lock_init(&stadiaff->lock);
98
99	hid_info(hid, "Force Feedback for Google Stadia controller\n");
100
101	return 0;
102}
103
104static int stadia_probe(struct hid_device *hdev, const struct hid_device_id *id)
105{
106	int ret;
107
108	ret = hid_parse(hdev);
109	if (ret) {
110		hid_err(hdev, "parse failed\n");
111		return ret;
112	}
113
114	ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT & ~HID_CONNECT_FF);
115	if (ret) {
116		hid_err(hdev, "hw start failed\n");
117		return ret;
118	}
119
120	ret = stadiaff_init(hdev);
121	if (ret) {
122		hid_err(hdev, "force feedback init failed\n");
123		hid_hw_stop(hdev);
124		return ret;
125	}
126
127	return 0;
128}
129
130static void stadia_remove(struct hid_device *hid)
131{
132	struct stadiaff_device *stadiaff = hid_get_drvdata(hid);
133	unsigned long flags;
134
135	spin_lock_irqsave(&stadiaff->lock, flags);
136	stadiaff->removed = true;
137	spin_unlock_irqrestore(&stadiaff->lock, flags);
138
139	cancel_work_sync(&stadiaff->work);
140	hid_hw_stop(hid);
141}
142
143static const struct hid_device_id stadia_devices[] = {
144	{ HID_USB_DEVICE(USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_STADIA) },
145	{ HID_BLUETOOTH_DEVICE(USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_STADIA) },
146	{ }
147};
148MODULE_DEVICE_TABLE(hid, stadia_devices);
149
150static struct hid_driver stadia_driver = {
151	.name = "stadia",
152	.id_table = stadia_devices,
153	.probe = stadia_probe,
154	.remove = stadia_remove,
155};
156module_hid_driver(stadia_driver);
157
158MODULE_LICENSE("GPL");
159