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/hid.h> 26 27 #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 56 struct lg3ff_device { 57 struct hid_report *report; 58 }; 59 60 static 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 93 hid_hw_request(hid, report, HID_REQ_SET_REPORT); 94 break; 95 } 96 return 0; 97 } 98 static 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; 118 119 hid_hw_request(hid, report, HID_REQ_SET_REPORT); 120 } 121 122 123 static const signed short ff3_joystick_ac[] = { 124 FF_CONSTANT, 125 FF_AUTOCENTER, 126 -1 127 }; 128 129 int 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)) { 142 hid_err(hid, "No output report found\n"); 143 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) { 149 hid_err(hid, "NULL output report\n"); 150 return -1; 151 } 152 153 field = report->field[0]; 154 if (!field) { 155 hid_err(hid, "NULL field\n"); 156 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; 169 170 hid_info(hid, "Force feedback for Logitech Flight System G940 by Gary Stein <LordCnidarian@gmail.com>\n"); 171 return 0; 172 } 173 174