drivers/hid/hid-lg3ff.c

   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  * Maxusage should always be 63 (maximum fields)
  70  * likely a better way to ensure this data is clean
  71  */
  72         memset(report->field[0]->value, 0, sizeof(__s32)*report->field[0]->maxusage);
  73
  74         switch (effect->type) {
  75         case FF_CONSTANT:
  76 /*
  77  * Already clamped in ff_memless
  78  * 0 is center (different then other logitech)
  79  */
  80                 x = effect->u.ramp.start_level;
  81                 y = effect->u.ramp.end_level;
  82
  83                 /* send command byte */
  84                 report->field[0]->value[0] = 0x51;
  85
  86 /*
  87  * Sign backwards from other Force3d pro
  88  * which get recast here in two's complement 8 bits
  89  */
  90                 report->field[0]->value[1] = (unsigned char)(-x);
  91                 report->field[0]->value[31] = (unsigned char)(-y);
  92
  93                 hid_hw_request(hid, report, HID_REQ_SET_REPORT);
  94                 break;
  95         }
  96         return 0;
  97 }
  98 static void hid_lg3ff_set_autocenter(struct input_dev *dev, u16 magnitude)
  99 {
 100         struct hid_device *hid = input_get_drvdata(dev);
 101         struct list_head *report_list = &hid->report_enum[HID_OUTPUT_REPORT].report_list;
 102         struct hid_report *report = list_entry(report_list->next, struct hid_report, list);
 103
 104 /*
 105  * Auto Centering probed from device
 106  * NOTE: deadman's switch on G940 must be covered
 107  * for effects to work
 108  */
 109         report->field[0]->value[0] = 0x51;
 110         report->field[0]->value[1] = 0x00;
 111         report->field[0]->value[2] = 0x00;
 112         report->field[0]->value[3] = 0x7F;
 113         report->field[0]->value[4] = 0x7F;
 114         report->field[0]->value[31] = 0x00;
 115         report->field[0]->value[32] = 0x00;
 116         report->field[0]->value[33] = 0x7F;
 117         report->field[0]->value[34] = 0x7F;
 118
 119         hid_hw_request(hid, report, HID_REQ_SET_REPORT);
 120 }
 121
 122
 123 static const signed short ff3_joystick_ac[] = {
 124         FF_CONSTANT,
 125         FF_AUTOCENTER,
 126         -1
 127 };
 128
 129 int lg3ff_init(struct hid_device *hid)
 130 {
 131         struct hid_input *hidinput = list_entry(hid->inputs.next, struct hid_input, list);
 132         struct list_head *report_list = &hid->report_enum[HID_OUTPUT_REPORT].report_list;
 133         struct input_dev *dev = hidinput->input;
 134         struct hid_report *report;
 135         struct hid_field *field;
 136         const signed short *ff_bits = ff3_joystick_ac;
 137         int error;
 138         int i;
 139
 140         /* Find the report to use */
 141         if (list_empty(report_list)) {
 142                 hid_err(hid, "No output report found\n");
 143                 return -1;
 144         }
 145
 146         /* Check that the report looks ok */
 147         report = list_entry(report_list->next, struct hid_report, list);
 148         if (!report) {
 149                 hid_err(hid, "NULL output report\n");
 150                 return -1;
 151         }
 152
 153         field = report->field[0];
 154         if (!field) {
 155                 hid_err(hid, "NULL field\n");
 156                 return -1;
 157         }
 158
 159         /* Assume single fixed device G940 */
 160         for (i = 0; ff_bits[i] >= 0; i++)
 161                 set_bit(ff_bits[i], dev->ffbit);
 162
 163         error = input_ff_create_memless(dev, NULL, hid_lg3ff_play);
 164         if (error)
 165                 return error;
 166
 167         if (test_bit(FF_AUTOCENTER, dev->ffbit))
 168                 dev->ff->set_autocenter = hid_lg3ff_set_autocenter;
 169
 170         hid_info(hid, "Force feedback for Logitech Flight System G940 by Gary Stein <LordCnidarian@gmail.com>\n");
 171         return 0;
 172 }
 173