1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* |
3 | * Force feedback support for Logitech Flight System G940 |
4 | * |
5 | * Copyright (c) 2009 Gary Stein <LordCnidarian@gmail.com> |
6 | */ |
7 | |
8 | /* |
9 | */ |
10 | |
11 | |
12 | #include <linux/input.h> |
13 | #include <linux/hid.h> |
14 | |
15 | #include "hid-lg.h" |
16 | |
17 | /* |
18 | * G940 Theory of Operation (from experimentation) |
19 | * |
20 | * There are 63 fields (only 3 of them currently used) |
21 | * 0 - seems to be command field |
22 | * 1 - 30 deal with the x axis |
23 | * 31 -60 deal with the y axis |
24 | * |
25 | * Field 1 is x axis constant force |
26 | * Field 31 is y axis constant force |
27 | * |
28 | * other interesting fields 1,2,3,4 on x axis |
29 | * (same for 31,32,33,34 on y axis) |
30 | * |
31 | * 0 0 127 127 makes the joystick autocenter hard |
32 | * |
33 | * 127 0 127 127 makes the joystick loose on the right, |
34 | * but stops all movemnt left |
35 | * |
36 | * -127 0 -127 -127 makes the joystick loose on the left, |
37 | * but stops all movement right |
38 | * |
39 | * 0 0 -127 -127 makes the joystick rattle very hard |
40 | * |
41 | * I'm sure these are effects that I don't know enough about them |
42 | */ |
43 | |
44 | struct lg3ff_device { |
45 | struct hid_report *report; |
46 | }; |
47 | |
48 | static int hid_lg3ff_play(struct input_dev *dev, void *data, |
49 | struct ff_effect *effect) |
50 | { |
51 | struct hid_device *hid = input_get_drvdata(dev); |
52 | struct list_head *report_list = &hid->report_enum[HID_OUTPUT_REPORT].report_list; |
53 | struct hid_report *report = list_entry(report_list->next, struct hid_report, list); |
54 | int x, y; |
55 | |
56 | /* |
57 | * Available values in the field should always be 63, but we only use up to |
58 | * 35. Instead, clear the entire area, however big it is. |
59 | */ |
60 | memset(report->field[0]->value, 0, |
61 | sizeof(__s32) * report->field[0]->report_count); |
62 | |
63 | switch (effect->type) { |
64 | case FF_CONSTANT: |
65 | /* |
66 | * Already clamped in ff_memless |
67 | * 0 is center (different then other logitech) |
68 | */ |
69 | x = effect->u.ramp.start_level; |
70 | y = effect->u.ramp.end_level; |
71 | |
72 | /* send command byte */ |
73 | report->field[0]->value[0] = 0x51; |
74 | |
75 | /* |
76 | * Sign backwards from other Force3d pro |
77 | * which get recast here in two's complement 8 bits |
78 | */ |
79 | report->field[0]->value[1] = (unsigned char)(-x); |
80 | report->field[0]->value[31] = (unsigned char)(-y); |
81 | |
82 | hid_hw_request(hdev: hid, report, reqtype: HID_REQ_SET_REPORT); |
83 | break; |
84 | } |
85 | return 0; |
86 | } |
87 | static void hid_lg3ff_set_autocenter(struct input_dev *dev, u16 magnitude) |
88 | { |
89 | struct hid_device *hid = input_get_drvdata(dev); |
90 | struct list_head *report_list = &hid->report_enum[HID_OUTPUT_REPORT].report_list; |
91 | struct hid_report *report = list_entry(report_list->next, struct hid_report, list); |
92 | |
93 | /* |
94 | * Auto Centering probed from device |
95 | * NOTE: deadman's switch on G940 must be covered |
96 | * for effects to work |
97 | */ |
98 | report->field[0]->value[0] = 0x51; |
99 | report->field[0]->value[1] = 0x00; |
100 | report->field[0]->value[2] = 0x00; |
101 | report->field[0]->value[3] = 0x7F; |
102 | report->field[0]->value[4] = 0x7F; |
103 | report->field[0]->value[31] = 0x00; |
104 | report->field[0]->value[32] = 0x00; |
105 | report->field[0]->value[33] = 0x7F; |
106 | report->field[0]->value[34] = 0x7F; |
107 | |
108 | hid_hw_request(hdev: hid, report, reqtype: HID_REQ_SET_REPORT); |
109 | } |
110 | |
111 | |
112 | static const signed short ff3_joystick_ac[] = { |
113 | FF_CONSTANT, |
114 | FF_AUTOCENTER, |
115 | -1 |
116 | }; |
117 | |
118 | int lg3ff_init(struct hid_device *hid) |
119 | { |
120 | struct hid_input *hidinput; |
121 | struct input_dev *dev; |
122 | const signed short *ff_bits = ff3_joystick_ac; |
123 | int error; |
124 | int i; |
125 | |
126 | if (list_empty(head: &hid->inputs)) { |
127 | hid_err(hid, "no inputs found\n" ); |
128 | return -ENODEV; |
129 | } |
130 | hidinput = list_entry(hid->inputs.next, struct hid_input, list); |
131 | dev = hidinput->input; |
132 | |
133 | /* Check that the report looks ok */ |
134 | if (!hid_validate_values(hid, type: HID_OUTPUT_REPORT, id: 0, field_index: 0, report_counts: 35)) |
135 | return -ENODEV; |
136 | |
137 | /* Assume single fixed device G940 */ |
138 | for (i = 0; ff_bits[i] >= 0; i++) |
139 | set_bit(nr: ff_bits[i], addr: dev->ffbit); |
140 | |
141 | error = input_ff_create_memless(dev, NULL, play_effect: hid_lg3ff_play); |
142 | if (error) |
143 | return error; |
144 | |
145 | if (test_bit(FF_AUTOCENTER, dev->ffbit)) |
146 | dev->ff->set_autocenter = hid_lg3ff_set_autocenter; |
147 | |
148 | hid_info(hid, "Force feedback for Logitech Flight System G940 by Gary Stein <LordCnidarian@gmail.com>\n" ); |
149 | return 0; |
150 | } |
151 | |
152 | |