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 | static int hid_lg3ff_play(struct input_dev *dev, void *data, |
45 | struct ff_effect *effect) |
46 | { |
47 | struct hid_device *hid = input_get_drvdata(dev); |
48 | struct list_head *report_list = &hid->report_enum[HID_OUTPUT_REPORT].report_list; |
49 | struct hid_report *report = list_entry(report_list->next, struct hid_report, list); |
50 | int x, y; |
51 | |
52 | /* |
53 | * Available values in the field should always be 63, but we only use up to |
54 | * 35. Instead, clear the entire area, however big it is. |
55 | */ |
56 | memset(report->field[0]->value, 0, |
57 | sizeof(__s32) * report->field[0]->report_count); |
58 | |
59 | switch (effect->type) { |
60 | case FF_CONSTANT: |
61 | /* |
62 | * Already clamped in ff_memless |
63 | * 0 is center (different then other logitech) |
64 | */ |
65 | x = effect->u.ramp.start_level; |
66 | y = effect->u.ramp.end_level; |
67 | |
68 | /* send command byte */ |
69 | report->field[0]->value[0] = 0x51; |
70 | |
71 | /* |
72 | * Sign backwards from other Force3d pro |
73 | * which get recast here in two's complement 8 bits |
74 | */ |
75 | report->field[0]->value[1] = (unsigned char)(-x); |
76 | report->field[0]->value[31] = (unsigned char)(-y); |
77 | |
78 | hid_hw_request(hdev: hid, report, reqtype: HID_REQ_SET_REPORT); |
79 | break; |
80 | } |
81 | return 0; |
82 | } |
83 | static void hid_lg3ff_set_autocenter(struct input_dev *dev, u16 magnitude) |
84 | { |
85 | struct hid_device *hid = input_get_drvdata(dev); |
86 | struct list_head *report_list = &hid->report_enum[HID_OUTPUT_REPORT].report_list; |
87 | struct hid_report *report = list_entry(report_list->next, struct hid_report, list); |
88 | |
89 | /* |
90 | * Auto Centering probed from device |
91 | * NOTE: deadman's switch on G940 must be covered |
92 | * for effects to work |
93 | */ |
94 | report->field[0]->value[0] = 0x51; |
95 | report->field[0]->value[1] = 0x00; |
96 | report->field[0]->value[2] = 0x00; |
97 | report->field[0]->value[3] = 0x7F; |
98 | report->field[0]->value[4] = 0x7F; |
99 | report->field[0]->value[31] = 0x00; |
100 | report->field[0]->value[32] = 0x00; |
101 | report->field[0]->value[33] = 0x7F; |
102 | report->field[0]->value[34] = 0x7F; |
103 | |
104 | hid_hw_request(hdev: hid, report, reqtype: HID_REQ_SET_REPORT); |
105 | } |
106 | |
107 | |
108 | static const signed short ff3_joystick_ac[] = { |
109 | FF_CONSTANT, |
110 | FF_AUTOCENTER, |
111 | -1 |
112 | }; |
113 | |
114 | int lg3ff_init(struct hid_device *hid) |
115 | { |
116 | struct hid_input *hidinput; |
117 | struct input_dev *dev; |
118 | const signed short *ff_bits = ff3_joystick_ac; |
119 | int error; |
120 | int i; |
121 | |
122 | if (list_empty(head: &hid->inputs)) { |
123 | hid_err(hid, "no inputs found\n" ); |
124 | return -ENODEV; |
125 | } |
126 | hidinput = list_entry(hid->inputs.next, struct hid_input, list); |
127 | dev = hidinput->input; |
128 | |
129 | /* Check that the report looks ok */ |
130 | if (!hid_validate_values(hid, type: HID_OUTPUT_REPORT, id: 0, field_index: 0, report_counts: 35)) |
131 | return -ENODEV; |
132 | |
133 | /* Assume single fixed device G940 */ |
134 | for (i = 0; ff_bits[i] >= 0; i++) |
135 | set_bit(nr: ff_bits[i], addr: dev->ffbit); |
136 | |
137 | error = input_ff_create_memless(dev, NULL, play_effect: hid_lg3ff_play); |
138 | if (error) |
139 | return error; |
140 | |
141 | if (test_bit(FF_AUTOCENTER, dev->ffbit)) |
142 | dev->ff->set_autocenter = hid_lg3ff_set_autocenter; |
143 | |
144 | hid_info(hid, "Force feedback for Logitech Flight System G940 by Gary Stein <LordCnidarian@gmail.com>\n" ); |
145 | return 0; |
146 | } |
147 | |
148 | |