1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Force feedback support for EMS Trio Linker Plus II
4 *
5 * Copyright (c) 2010 Ignaz Forster <ignaz.forster@gmx.de>
6 */
7
8 /*
9 */
10
11
12 #include <linux/hid.h>
13 #include <linux/input.h>
14 #include <linux/module.h>
15
16 #include "hid-ids.h"
17
18 struct emsff_device {
19 struct hid_report *report;
20 };
21
emsff_play(struct input_dev * dev,void * data,struct ff_effect * effect)22 static int emsff_play(struct input_dev *dev, void *data,
23 struct ff_effect *effect)
24 {
25 struct hid_device *hid = input_get_drvdata(dev);
26 struct emsff_device *emsff = data;
27 int weak, strong;
28
29 weak = effect->u.rumble.weak_magnitude;
30 strong = effect->u.rumble.strong_magnitude;
31
32 dbg_hid("called with 0x%04x 0x%04x\n", strong, weak);
33
34 weak = weak * 0xff / 0xffff;
35 strong = strong * 0xff / 0xffff;
36
37 emsff->report->field[0]->value[1] = weak;
38 emsff->report->field[0]->value[2] = strong;
39
40 dbg_hid("running with 0x%02x 0x%02x\n", strong, weak);
41 hid_hw_request(hid, emsff->report, HID_REQ_SET_REPORT);
42
43 return 0;
44 }
45
emsff_init(struct hid_device * hid)46 static int emsff_init(struct hid_device *hid)
47 {
48 struct emsff_device *emsff;
49 struct hid_report *report;
50 struct hid_input *hidinput;
51 struct list_head *report_list =
52 &hid->report_enum[HID_OUTPUT_REPORT].report_list;
53 struct input_dev *dev;
54 int error;
55
56 if (list_empty(&hid->inputs)) {
57 hid_err(hid, "no inputs found\n");
58 return -ENODEV;
59 }
60 hidinput = list_first_entry(&hid->inputs, struct hid_input, list);
61 dev = hidinput->input;
62
63 if (list_empty(report_list)) {
64 hid_err(hid, "no output reports found\n");
65 return -ENODEV;
66 }
67
68 report = list_first_entry(report_list, struct hid_report, list);
69 if (report->maxfield < 1) {
70 hid_err(hid, "no fields in the report\n");
71 return -ENODEV;
72 }
73
74 if (report->field[0]->report_count < 7) {
75 hid_err(hid, "not enough values in the field\n");
76 return -ENODEV;
77 }
78
79 emsff = kzalloc(sizeof(struct emsff_device), GFP_KERNEL);
80 if (!emsff)
81 return -ENOMEM;
82
83 set_bit(FF_RUMBLE, dev->ffbit);
84
85 error = input_ff_create_memless(dev, emsff, emsff_play);
86 if (error) {
87 kfree(emsff);
88 return error;
89 }
90
91 emsff->report = report;
92 emsff->report->field[0]->value[0] = 0x01;
93 emsff->report->field[0]->value[1] = 0x00;
94 emsff->report->field[0]->value[2] = 0x00;
95 emsff->report->field[0]->value[3] = 0x00;
96 emsff->report->field[0]->value[4] = 0x00;
97 emsff->report->field[0]->value[5] = 0x00;
98 emsff->report->field[0]->value[6] = 0x00;
99 hid_hw_request(hid, emsff->report, HID_REQ_SET_REPORT);
100
101 hid_info(hid, "force feedback for EMS based devices by Ignaz Forster <ignaz.forster@gmx.de>\n");
102
103 return 0;
104 }
105
ems_probe(struct hid_device * hdev,const struct hid_device_id * id)106 static int ems_probe(struct hid_device *hdev, const struct hid_device_id *id)
107 {
108 int ret;
109
110 ret = hid_parse(hdev);
111 if (ret) {
112 hid_err(hdev, "parse failed\n");
113 goto err;
114 }
115
116 ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT & ~HID_CONNECT_FF);
117 if (ret) {
118 hid_err(hdev, "hw start failed\n");
119 goto err;
120 }
121
122 ret = emsff_init(hdev);
123 if (ret) {
124 dev_err(&hdev->dev, "force feedback init failed\n");
125 hid_hw_stop(hdev);
126 goto err;
127 }
128
129 return 0;
130 err:
131 return ret;
132 }
133
134 static const struct hid_device_id ems_devices[] = {
135 { HID_USB_DEVICE(USB_VENDOR_ID_EMS, USB_DEVICE_ID_EMS_TRIO_LINKER_PLUS_II) },
136 { }
137 };
138 MODULE_DEVICE_TABLE(hid, ems_devices);
139
140 static struct hid_driver ems_driver = {
141 .name = "hkems",
142 .id_table = ems_devices,
143 .probe = ems_probe,
144 };
145 module_hid_driver(ems_driver);
146
147 MODULE_LICENSE("GPL");
148
149