cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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hid-lg3ff.c (3907B)

      1// SPDX-License-Identifier: GPL-2.0-or-later
      2/*
      3 *  Force feedback support for Logitech Flight System G940
      4 *
      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 field
     22 * 1 - 30 deal with the x axis
     23 * 31 -60 deal with the y axis
     24 *
     25 * Field 1 is x axis constant force
     26 * Field 31 is y axis constant force
     27 *
     28 * other interesting fields 1,2,3,4 on x axis
     29 * (same for 31,32,33,34 on y axis)
     30 *
     31 * 0 0 127 127 makes the joystick autocenter hard
     32 *
     33 * 127 0 127 127 makes the joystick loose on the right,
     34 * but stops all movemnt left
     35 *
     36 * -127 0 -127 -127 makes the joystick loose on the left,
     37 * but stops all movement right
     38 *
     39 * 0 0 -127 -127 makes the joystick rattle very hard
     40 *
     41 * I'm sure these are effects that I don't know enough about them
     42 */
     43
     44struct lg3ff_device {
     45	struct hid_report *report;
     46};
     47
     48static int hid_lg3ff_play(struct input_dev *dev, void *data,
     49			 struct ff_effect *effect)
     50{
     51	struct hid_device *hid = input_get_drvdata(dev);
     52	struct list_head *report_list = &hid->report_enum[HID_OUTPUT_REPORT].report_list;
     53	struct hid_report *report = list_entry(report_list->next, struct hid_report, list);
     54	int x, y;
     55
     56/*
     57 * Available values in the field should always be 63, but we only use up to
     58 * 35. Instead, clear the entire area, however big it is.
     59 */
     60	memset(report->field[0]->value, 0,
     61	       sizeof(__s32) * report->field[0]->report_count);
     62
     63	switch (effect->type) {
     64	case FF_CONSTANT:
     65/*
     66 * Already clamped in ff_memless
     67 * 0 is center (different then other logitech)
     68 */
     69		x = effect->u.ramp.start_level;
     70		y = effect->u.ramp.end_level;
     71
     72		/* send command byte */
     73		report->field[0]->value[0] = 0x51;
     74
     75/*
     76 * Sign backwards from other Force3d pro
     77 * which get recast here in two's complement 8 bits
     78 */
     79		report->field[0]->value[1] = (unsigned char)(-x);
     80		report->field[0]->value[31] = (unsigned char)(-y);
     81
     82		hid_hw_request(hid, report, HID_REQ_SET_REPORT);
     83		break;
     84	}
     85	return 0;
     86}
     87static void hid_lg3ff_set_autocenter(struct input_dev *dev, u16 magnitude)
     88{
     89	struct hid_device *hid = input_get_drvdata(dev);
     90	struct list_head *report_list = &hid->report_enum[HID_OUTPUT_REPORT].report_list;
     91	struct hid_report *report = list_entry(report_list->next, struct hid_report, list);
     92
     93/*
     94 * Auto Centering probed from device
     95 * NOTE: deadman's switch on G940 must be covered
     96 * for effects to work
     97 */
     98	report->field[0]->value[0] = 0x51;
     99	report->field[0]->value[1] = 0x00;
    100	report->field[0]->value[2] = 0x00;
    101	report->field[0]->value[3] = 0x7F;
    102	report->field[0]->value[4] = 0x7F;
    103	report->field[0]->value[31] = 0x00;
    104	report->field[0]->value[32] = 0x00;
    105	report->field[0]->value[33] = 0x7F;
    106	report->field[0]->value[34] = 0x7F;
    107
    108	hid_hw_request(hid, report, HID_REQ_SET_REPORT);
    109}
    110
    111
    112static const signed short ff3_joystick_ac[] = {
    113	FF_CONSTANT,
    114	FF_AUTOCENTER,
    115	-1
    116};
    117
    118int lg3ff_init(struct hid_device *hid)
    119{
    120	struct hid_input *hidinput;
    121	struct input_dev *dev;
    122	const signed short *ff_bits = ff3_joystick_ac;
    123	int error;
    124	int i;
    125
    126	if (list_empty(&hid->inputs)) {
    127		hid_err(hid, "no inputs found\n");
    128		return -ENODEV;
    129	}
    130	hidinput = list_entry(hid->inputs.next, struct hid_input, list);
    131	dev = hidinput->input;
    132
    133	/* Check that the report looks ok */
    134	if (!hid_validate_values(hid, HID_OUTPUT_REPORT, 0, 0, 35))
    135		return -ENODEV;
    136
    137	/* Assume single fixed device G940 */
    138	for (i = 0; ff_bits[i] >= 0; i++)
    139		set_bit(ff_bits[i], dev->ffbit);
    140
    141	error = input_ff_create_memless(dev, NULL, hid_lg3ff_play);
    142	if (error)
    143		return error;
    144
    145	if (test_bit(FF_AUTOCENTER, dev->ffbit))
    146		dev->ff->set_autocenter = hid_lg3ff_set_autocenter;
    147
    148	hid_info(hid, "Force feedback for Logitech Flight System G940 by Gary Stein <LordCnidarian@gmail.com>\n");
    149	return 0;
    150}
    151