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/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                 err_hid("No output report found");
 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                 err_hid("NULL output report");
 152                 return -1;
 153         }
 154
 155         field = report->field[0];
 156         if (!field) {
 157                 err_hid("NULL field");
 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         dev_info(&hid->dev, "Force feedback for Logitech Flight System G940 by "
 173                         "Gary Stein <LordCnidarian@gmail.com>\n");
 174         return 0;
 175 }
 176