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
18struct emsff_device {
19	struct hid_report *report;
20};
21
22static 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
46static 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
106static 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;
130err:
131	return ret;
132}
133
134static 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};
138MODULE_DEVICE_TABLE(hid, ems_devices);
139
140static struct hid_driver ems_driver = {
141	.name = "hkems",
142	.id_table = ems_devices,
143	.probe = ems_probe,
144};
145module_hid_driver(ems_driver);
146
147MODULE_LICENSE("GPL");
148
149