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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
44struct lg3ff_device {
45 struct hid_report *report;
46};
47
48static 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(hid, report, HID_REQ_SET_REPORT);
83 break;
84 }
85 return 0;
86}
87static 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(hid, report, HID_REQ_SET_REPORT);
109}
110
111
112static const signed short ff3_joystick_ac[] = {
113 FF_CONSTANT,
114 FF_AUTOCENTER,
115 -1
116};
117
118int 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(&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, HID_OUTPUT_REPORT, 0, 0, 35))
135 return -ENODEV;
136
137 /* Assume single fixed device G940 */
138 for (i = 0; ff_bits[i] >= 0; i++)
139 set_bit(ff_bits[i], dev->ffbit);
140
141 error = input_ff_create_memless(dev, NULL, 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
1/*
2 * Force feedback support for Logitech Flight System G940
3 *
4 * Copyright (c) 2009 Gary Stein <LordCnidarian@gmail.com>
5 */
6
7/*
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
21 */
22
23
24#include <linux/input.h>
25#include <linux/usb.h>
26#include <linux/hid.h>
27
28#include "usbhid/usbhid.h"
29#include "hid-lg.h"
30
31/*
32 * G940 Theory of Operation (from experimentation)
33 *
34 * There are 63 fields (only 3 of them currently used)
35 * 0 - seems to be command field
36 * 1 - 30 deal with the x axis
37 * 31 -60 deal with the y axis
38 *
39 * Field 1 is x axis constant force
40 * Field 31 is y axis constant force
41 *
42 * other interesting fields 1,2,3,4 on x axis
43 * (same for 31,32,33,34 on y axis)
44 *
45 * 0 0 127 127 makes the joystick autocenter hard
46 *
47 * 127 0 127 127 makes the joystick loose on the right,
48 * but stops all movemnt left
49 *
50 * -127 0 -127 -127 makes the joystick loose on the left,
51 * but stops all movement right
52 *
53 * 0 0 -127 -127 makes the joystick rattle very hard
54 *
55 * I'm sure these are effects that I don't know enough about them
56 */
57
58struct lg3ff_device {
59 struct hid_report *report;
60};
61
62static int hid_lg3ff_play(struct input_dev *dev, void *data,
63 struct ff_effect *effect)
64{
65 struct hid_device *hid = input_get_drvdata(dev);
66 struct list_head *report_list = &hid->report_enum[HID_OUTPUT_REPORT].report_list;
67 struct hid_report *report = list_entry(report_list->next, struct hid_report, list);
68 int x, y;
69
70/*
71 * Maxusage should always be 63 (maximum fields)
72 * likely a better way to ensure this data is clean
73 */
74 memset(report->field[0]->value, 0, sizeof(__s32)*report->field[0]->maxusage);
75
76 switch (effect->type) {
77 case FF_CONSTANT:
78/*
79 * Already clamped in ff_memless
80 * 0 is center (different then other logitech)
81 */
82 x = effect->u.ramp.start_level;
83 y = effect->u.ramp.end_level;
84
85 /* send command byte */
86 report->field[0]->value[0] = 0x51;
87
88/*
89 * Sign backwards from other Force3d pro
90 * which get recast here in two's complement 8 bits
91 */
92 report->field[0]->value[1] = (unsigned char)(-x);
93 report->field[0]->value[31] = (unsigned char)(-y);
94
95 usbhid_submit_report(hid, report, USB_DIR_OUT);
96 break;
97 }
98 return 0;
99}
100static void hid_lg3ff_set_autocenter(struct input_dev *dev, u16 magnitude)
101{
102 struct hid_device *hid = input_get_drvdata(dev);
103 struct list_head *report_list = &hid->report_enum[HID_OUTPUT_REPORT].report_list;
104 struct hid_report *report = list_entry(report_list->next, struct hid_report, list);
105
106/*
107 * Auto Centering probed from device
108 * NOTE: deadman's switch on G940 must be covered
109 * for effects to work
110 */
111 report->field[0]->value[0] = 0x51;
112 report->field[0]->value[1] = 0x00;
113 report->field[0]->value[2] = 0x00;
114 report->field[0]->value[3] = 0x7F;
115 report->field[0]->value[4] = 0x7F;
116 report->field[0]->value[31] = 0x00;
117 report->field[0]->value[32] = 0x00;
118 report->field[0]->value[33] = 0x7F;
119 report->field[0]->value[34] = 0x7F;
120
121 usbhid_submit_report(hid, report, USB_DIR_OUT);
122}
123
124
125static const signed short ff3_joystick_ac[] = {
126 FF_CONSTANT,
127 FF_AUTOCENTER,
128 -1
129};
130
131int lg3ff_init(struct hid_device *hid)
132{
133 struct hid_input *hidinput = list_entry(hid->inputs.next, struct hid_input, list);
134 struct list_head *report_list = &hid->report_enum[HID_OUTPUT_REPORT].report_list;
135 struct input_dev *dev = hidinput->input;
136 struct hid_report *report;
137 struct hid_field *field;
138 const signed short *ff_bits = ff3_joystick_ac;
139 int error;
140 int i;
141
142 /* Find the report to use */
143 if (list_empty(report_list)) {
144 hid_err(hid, "No output report found\n");
145 return -1;
146 }
147
148 /* Check that the report looks ok */
149 report = list_entry(report_list->next, struct hid_report, list);
150 if (!report) {
151 hid_err(hid, "NULL output report\n");
152 return -1;
153 }
154
155 field = report->field[0];
156 if (!field) {
157 hid_err(hid, "NULL field\n");
158 return -1;
159 }
160
161 /* Assume single fixed device G940 */
162 for (i = 0; ff_bits[i] >= 0; i++)
163 set_bit(ff_bits[i], dev->ffbit);
164
165 error = input_ff_create_memless(dev, NULL, hid_lg3ff_play);
166 if (error)
167 return error;
168
169 if (test_bit(FF_AUTOCENTER, dev->ffbit))
170 dev->ff->set_autocenter = hid_lg3ff_set_autocenter;
171
172 hid_info(hid, "Force feedback for Logitech Flight System G940 by Gary Stein <LordCnidarian@gmail.com>\n");
173 return 0;
174}
175