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Gary Stein74f292c2010-01-13 00:25:58 +01001/*
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>
Gary Stein74f292c2010-01-13 00:25:58 +010025#include <linux/hid.h>
26
Gary Stein74f292c2010-01-13 00:25:58 +010027#include "hid-lg.h"
28
29/*
30 * G940 Theory of Operation (from experimentation)
31 *
32 * There are 63 fields (only 3 of them currently used)
33 * 0 - seems to be command field
34 * 1 - 30 deal with the x axis
35 * 31 -60 deal with the y axis
36 *
37 * Field 1 is x axis constant force
38 * Field 31 is y axis constant force
39 *
40 * other interesting fields 1,2,3,4 on x axis
41 * (same for 31,32,33,34 on y axis)
42 *
43 * 0 0 127 127 makes the joystick autocenter hard
44 *
45 * 127 0 127 127 makes the joystick loose on the right,
46 * but stops all movemnt left
47 *
48 * -127 0 -127 -127 makes the joystick loose on the left,
49 * but stops all movement right
50 *
51 * 0 0 -127 -127 makes the joystick rattle very hard
52 *
53 * I'm sure these are effects that I don't know enough about them
54 */
55
56struct lg3ff_device {
57 struct hid_report *report;
58};
59
60static int hid_lg3ff_play(struct input_dev *dev, void *data,
61 struct ff_effect *effect)
62{
63 struct hid_device *hid = input_get_drvdata(dev);
64 struct list_head *report_list = &hid->report_enum[HID_OUTPUT_REPORT].report_list;
65 struct hid_report *report = list_entry(report_list->next, struct hid_report, list);
66 int x, y;
67
68/*
69 * Maxusage should always be 63 (maximum fields)
70 * likely a better way to ensure this data is clean
71 */
72 memset(report->field[0]->value, 0, sizeof(__s32)*report->field[0]->maxusage);
73
74 switch (effect->type) {
75 case FF_CONSTANT:
76/*
77 * Already clamped in ff_memless
78 * 0 is center (different then other logitech)
79 */
80 x = effect->u.ramp.start_level;
81 y = effect->u.ramp.end_level;
82
83 /* send command byte */
84 report->field[0]->value[0] = 0x51;
85
86/*
87 * Sign backwards from other Force3d pro
88 * which get recast here in two's complement 8 bits
89 */
90 report->field[0]->value[1] = (unsigned char)(-x);
91 report->field[0]->value[31] = (unsigned char)(-y);
92
Benjamin Tissoiresd88142722013-02-25 11:31:46 +010093 hid_hw_request(hid, report, HID_REQ_SET_REPORT);
Gary Stein74f292c2010-01-13 00:25:58 +010094 break;
95 }
96 return 0;
97}
98static void hid_lg3ff_set_autocenter(struct input_dev *dev, u16 magnitude)
99{
100 struct hid_device *hid = input_get_drvdata(dev);
101 struct list_head *report_list = &hid->report_enum[HID_OUTPUT_REPORT].report_list;
102 struct hid_report *report = list_entry(report_list->next, struct hid_report, list);
103
104/*
105 * Auto Centering probed from device
106 * NOTE: deadman's switch on G940 must be covered
107 * for effects to work
108 */
109 report->field[0]->value[0] = 0x51;
110 report->field[0]->value[1] = 0x00;
111 report->field[0]->value[2] = 0x00;
112 report->field[0]->value[3] = 0x7F;
113 report->field[0]->value[4] = 0x7F;
114 report->field[0]->value[31] = 0x00;
115 report->field[0]->value[32] = 0x00;
116 report->field[0]->value[33] = 0x7F;
117 report->field[0]->value[34] = 0x7F;
118
Benjamin Tissoiresd88142722013-02-25 11:31:46 +0100119 hid_hw_request(hid, report, HID_REQ_SET_REPORT);
Gary Stein74f292c2010-01-13 00:25:58 +0100120}
121
122
123static const signed short ff3_joystick_ac[] = {
124 FF_CONSTANT,
125 FF_AUTOCENTER,
126 -1
127};
128
129int lg3ff_init(struct hid_device *hid)
130{
131 struct hid_input *hidinput = list_entry(hid->inputs.next, struct hid_input, list);
132 struct list_head *report_list = &hid->report_enum[HID_OUTPUT_REPORT].report_list;
133 struct input_dev *dev = hidinput->input;
134 struct hid_report *report;
135 struct hid_field *field;
136 const signed short *ff_bits = ff3_joystick_ac;
137 int error;
138 int i;
139
140 /* Find the report to use */
141 if (list_empty(report_list)) {
Joe Perches4291ee32010-12-09 19:29:03 -0800142 hid_err(hid, "No output report found\n");
Gary Stein74f292c2010-01-13 00:25:58 +0100143 return -1;
144 }
145
146 /* Check that the report looks ok */
147 report = list_entry(report_list->next, struct hid_report, list);
148 if (!report) {
Joe Perches4291ee32010-12-09 19:29:03 -0800149 hid_err(hid, "NULL output report\n");
Gary Stein74f292c2010-01-13 00:25:58 +0100150 return -1;
151 }
152
153 field = report->field[0];
154 if (!field) {
Joe Perches4291ee32010-12-09 19:29:03 -0800155 hid_err(hid, "NULL field\n");
Gary Stein74f292c2010-01-13 00:25:58 +0100156 return -1;
157 }
158
159 /* Assume single fixed device G940 */
160 for (i = 0; ff_bits[i] >= 0; i++)
161 set_bit(ff_bits[i], dev->ffbit);
162
163 error = input_ff_create_memless(dev, NULL, hid_lg3ff_play);
164 if (error)
165 return error;
166
167 if (test_bit(FF_AUTOCENTER, dev->ffbit))
168 dev->ff->set_autocenter = hid_lg3ff_set_autocenter;
169
Joe Perches4291ee32010-12-09 19:29:03 -0800170 hid_info(hid, "Force feedback for Logitech Flight System G940 by Gary Stein <LordCnidarian@gmail.com>\n");
Gary Stein74f292c2010-01-13 00:25:58 +0100171 return 0;
172}
173