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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * Force feedback support for Logitech Flight System G9404 *5 * Copyright (c) 2009 Gary Stein <LordCnidarian@gmail.com>6 */7 8/*9 */10 11 12#include <linux/input.h>13#include <linux/hid.h>14 15#include "hid-lg.h"16 17/*18 * G940 Theory of Operation (from experimentation)19 *20 * There are 63 fields (only 3 of them currently used)21 * 0 - seems to be command field22 * 1 - 30 deal with the x axis23 * 31 -60 deal with the y axis24 *25 * Field 1 is x axis constant force26 * Field 31 is y axis constant force27 *28 * other interesting fields 1,2,3,4 on x axis29 * (same for 31,32,33,34 on y axis)30 *31 * 0 0 127 127 makes the joystick autocenter hard32 *33 * 127 0 127 127 makes the joystick loose on the right,34 * but stops all movemnt left35 *36 * -127 0 -127 -127 makes the joystick loose on the left,37 * but stops all movement right38 *39 * 0 0 -127 -127 makes the joystick rattle very hard40 *41 * I'm sure these are effects that I don't know enough about them42 */43 44static int hid_lg3ff_play(struct input_dev *dev, void *data,45 struct ff_effect *effect)46{47 struct hid_device *hid = input_get_drvdata(dev);48 struct list_head *report_list = &hid->report_enum[HID_OUTPUT_REPORT].report_list;49 struct hid_report *report = list_entry(report_list->next, struct hid_report, list);50 int x, y;51 52/*53 * Available values in the field should always be 63, but we only use up to54 * 35. Instead, clear the entire area, however big it is.55 */56 memset(report->field[0]->value, 0,57 sizeof(__s32) * report->field[0]->report_count);58 59 switch (effect->type) {60 case FF_CONSTANT:61/*62 * Already clamped in ff_memless63 * 0 is center (different then other logitech)64 */65 x = effect->u.ramp.start_level;66 y = effect->u.ramp.end_level;67 68 /* send command byte */69 report->field[0]->value[0] = 0x51;70 71/*72 * Sign backwards from other Force3d pro73 * which get recast here in two's complement 8 bits74 */75 report->field[0]->value[1] = (unsigned char)(-x);76 report->field[0]->value[31] = (unsigned char)(-y);77 78 hid_hw_request(hid, report, HID_REQ_SET_REPORT);79 break;80 }81 return 0;82}83static void hid_lg3ff_set_autocenter(struct input_dev *dev, u16 magnitude)84{85 struct hid_device *hid = input_get_drvdata(dev);86 struct list_head *report_list = &hid->report_enum[HID_OUTPUT_REPORT].report_list;87 struct hid_report *report = list_entry(report_list->next, struct hid_report, list);88 89/*90 * Auto Centering probed from device91 * NOTE: deadman's switch on G940 must be covered92 * for effects to work93 */94 report->field[0]->value[0] = 0x51;95 report->field[0]->value[1] = 0x00;96 report->field[0]->value[2] = 0x00;97 report->field[0]->value[3] = 0x7F;98 report->field[0]->value[4] = 0x7F;99 report->field[0]->value[31] = 0x00;100 report->field[0]->value[32] = 0x00;101 report->field[0]->value[33] = 0x7F;102 report->field[0]->value[34] = 0x7F;103 104 hid_hw_request(hid, report, HID_REQ_SET_REPORT);105}106 107 108static const signed short ff3_joystick_ac[] = {109 FF_CONSTANT,110 FF_AUTOCENTER,111 -1112};113 114int lg3ff_init(struct hid_device *hid)115{116 struct hid_input *hidinput;117 struct input_dev *dev;118 const signed short *ff_bits = ff3_joystick_ac;119 int error;120 int i;121 122 if (list_empty(&hid->inputs)) {123 hid_err(hid, "no inputs found\n");124 return -ENODEV;125 }126 hidinput = list_entry(hid->inputs.next, struct hid_input, list);127 dev = hidinput->input;128 129 /* Check that the report looks ok */130 if (!hid_validate_values(hid, HID_OUTPUT_REPORT, 0, 0, 35))131 return -ENODEV;132 133 /* Assume single fixed device G940 */134 for (i = 0; ff_bits[i] >= 0; i++)135 set_bit(ff_bits[i], dev->ffbit);136 137 error = input_ff_create_memless(dev, NULL, hid_lg3ff_play);138 if (error)139 return error;140 141 if (test_bit(FF_AUTOCENTER, dev->ffbit))142 dev->ff->set_autocenter = hid_lg3ff_set_autocenter;143 144 hid_info(hid, "Force feedback for Logitech Flight System G940 by Gary Stein <LordCnidarian@gmail.com>\n");145 return 0;146}147 148