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 
17 struct 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 
27 static 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 
42 static 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 
60 static 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 
104 static 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 
130 static 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 
143 static 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 };
148 MODULE_DEVICE_TABLE(hid, stadia_devices);
149 
150 static struct hid_driver stadia_driver = {
151 	.name = "stadia",
152 	.id_table = stadia_devices,
153 	.probe = stadia_probe,
154 	.remove = stadia_remove,
155 };
156 module_hid_driver(stadia_driver);
157 
158 MODULE_LICENSE("GPL");
159