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 58 struct lg3ff_device { 59 struct hid_report *report; 60 }; 61 62 static 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 } 100 static 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 } 123 124 125 static const signed short ff3_joystick_ac[] = { 126 FF_CONSTANT, 127 FF_AUTOCENTER, 128 -1 129 }; 130 131 int 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 } 175 176