/* * Force feedback support for Logitech Flight System G940 * * Copyright (c) 2009 Gary Stein <LordCnidarian@gmail.com> */ /* * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #include <linux/input.h> #include <linux/usb.h> #include <linux/hid.h> #include "usbhid/usbhid.h" #include "hid-lg.h" /* * G940 Theory of Operation (from experimentation) * * There are 63 fields (only 3 of them currently used) * 0 - seems to be command field * 1 - 30 deal with the x axis * 31 -60 deal with the y axis * * Field 1 is x axis constant force * Field 31 is y axis constant force * * other interesting fields 1,2,3,4 on x axis * (same for 31,32,33,34 on y axis) * * 0 0 127 127 makes the joystick autocenter hard * * 127 0 127 127 makes the joystick loose on the right, * but stops all movemnt left * * -127 0 -127 -127 makes the joystick loose on the left, * but stops all movement right * * 0 0 -127 -127 makes the joystick rattle very hard * * I'm sure these are effects that I don't know enough about them */ struct lg3ff_device { struct hid_report *report; }; static int hid_lg3ff_play(struct input_dev *dev, void *data, struct ff_effect *effect) { struct hid_device *hid = input_get_drvdata(dev); struct list_head *report_list = &hid->report_enum[HID_OUTPUT_REPORT].report_list; struct hid_report *report = list_entry(report_list->next, struct hid_report, list); int x, y; /* * Maxusage should always be 63 (maximum fields) * likely a better way to ensure this data is clean */ memset(report->field[0]->value, 0, sizeof(__s32)*report->field[0]->maxusage); switch (effect->type) { case FF_CONSTANT: /* * Already clamped in ff_memless * 0 is center (different then other logitech) */ x = effect->u.ramp.start_level; y = effect->u.ramp.end_level; /* send command byte */ report->field[0]->value[0] = 0x51; /* * Sign backwards from other Force3d pro * which get recast here in two's complement 8 bits */ report->field[0]->value[1] = (unsigned char)(-x); report->field[0]->value[31] = (unsigned char)(-y); usbhid_submit_report(hid, report, USB_DIR_OUT); break; } return 0; } static void hid_lg3ff_set_autocenter(struct input_dev *dev, u16 magnitude) { struct hid_device *hid = input_get_drvdata(dev); struct list_head *report_list = &hid->report_enum[HID_OUTPUT_REPORT].report_list; struct hid_report *report = list_entry(report_list->next, struct hid_report, list); /* * Auto Centering probed from device * NOTE: deadman's switch on G940 must be covered * for effects to work */ report->field[0]->value[0] = 0x51; report->field[0]->value[1] = 0x00; report->field[0]->value[2] = 0x00; report->field[0]->value[3] = 0x7F; report->field[0]->value[4] = 0x7F; report->field[0]->value[31] = 0x00; report->field[0]->value[32] = 0x00; report->field[0]->value[33] = 0x7F; report->field[0]->value[34] = 0x7F; usbhid_submit_report(hid, report, USB_DIR_OUT); } static const signed short ff3_joystick_ac[] = { FF_CONSTANT, FF_AUTOCENTER, -1 }; int lg3ff_init(struct hid_device *hid) { struct hid_input *hidinput = list_entry(hid->inputs.next, struct hid_input, list); struct list_head *report_list = &hid->report_enum[HID_OUTPUT_REPORT].report_list; struct input_dev *dev = hidinput->input; struct hid_report *report; struct hid_field *field; const signed short *ff_bits = ff3_joystick_ac; int error; int i; /* Find the report to use */ if (list_empty(report_list)) { err_hid("No output report found"); return -1; } /* Check that the report looks ok */ report = list_entry(report_list->next, struct hid_report, list); if (!report) { err_hid("NULL output report"); return -1; } field = report->field[0]; if (!field) { err_hid("NULL field"); return -1; } /* Assume single fixed device G940 */ for (i = 0; ff_bits[i] >= 0; i++) set_bit(ff_bits[i], dev->ffbit); error = input_ff_create_memless(dev, NULL, hid_lg3ff_play); if (error) return error; if (test_bit(FF_AUTOCENTER, dev->ffbit)) dev->ff->set_autocenter = hid_lg3ff_set_autocenter; dev_info(&hid->dev, "Force feedback for Logitech Flight System G940 by " "Gary Stein <LordCnidarian@gmail.com>\n"); return 0; }