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 * Available values in the field should always be 63, but we only use up to 70 * 35. Instead, clear the entire area, however big it is. 71 */ 72 memset(report->field[0]->value, 0, 73 sizeof(__s32) * report->field[0]->report_count); 74 75 switch (effect->type) { 76 case FF_CONSTANT: 77 /* 78 * Already clamped in ff_memless 79 * 0 is center (different then other logitech) 80 */ 81 x = effect->u.ramp.start_level; 82 y = effect->u.ramp.end_level; 83 84 /* send command byte */ 85 report->field[0]->value[0] = 0x51; 86 87 /* 88 * Sign backwards from other Force3d pro 89 * which get recast here in two's complement 8 bits 90 */ 91 report->field[0]->value[1] = (unsigned char)(-x); 92 report->field[0]->value[31] = (unsigned char)(-y); 93 94 hid_hw_request(hid, report, HID_REQ_SET_REPORT); 95 break; 96 } 97 return 0; 98 } 99 static void hid_lg3ff_set_autocenter(struct input_dev *dev, u16 magnitude) 100 { 101 struct hid_device *hid = input_get_drvdata(dev); 102 struct list_head *report_list = &hid->report_enum[HID_OUTPUT_REPORT].report_list; 103 struct hid_report *report = list_entry(report_list->next, struct hid_report, list); 104 105 /* 106 * Auto Centering probed from device 107 * NOTE: deadman's switch on G940 must be covered 108 * for effects to work 109 */ 110 report->field[0]->value[0] = 0x51; 111 report->field[0]->value[1] = 0x00; 112 report->field[0]->value[2] = 0x00; 113 report->field[0]->value[3] = 0x7F; 114 report->field[0]->value[4] = 0x7F; 115 report->field[0]->value[31] = 0x00; 116 report->field[0]->value[32] = 0x00; 117 report->field[0]->value[33] = 0x7F; 118 report->field[0]->value[34] = 0x7F; 119 120 hid_hw_request(hid, report, HID_REQ_SET_REPORT); 121 } 122 123 124 static const signed short ff3_joystick_ac[] = { 125 FF_CONSTANT, 126 FF_AUTOCENTER, 127 -1 128 }; 129 130 int lg3ff_init(struct hid_device *hid) 131 { 132 struct hid_input *hidinput = list_entry(hid->inputs.next, struct hid_input, list); 133 struct input_dev *dev = hidinput->input; 134 const signed short *ff_bits = ff3_joystick_ac; 135 int error; 136 int i; 137 138 /* Check that the report looks ok */ 139 if (!hid_validate_values(hid, HID_OUTPUT_REPORT, 0, 0, 35)) 140 return -ENODEV; 141 142 /* Assume single fixed device G940 */ 143 for (i = 0; ff_bits[i] >= 0; i++) 144 set_bit(ff_bits[i], dev->ffbit); 145 146 error = input_ff_create_memless(dev, NULL, hid_lg3ff_play); 147 if (error) 148 return error; 149 150 if (test_bit(FF_AUTOCENTER, dev->ffbit)) 151 dev->ff->set_autocenter = hid_lg3ff_set_autocenter; 152 153 hid_info(hid, "Force feedback for Logitech Flight System G940 by Gary Stein <LordCnidarian@gmail.com>\n"); 154 return 0; 155 } 156 157