linux/drivers/hid/hid-emsff.c
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   1/*
   2 *  Force feedback support for EMS Trio Linker Plus II
   3 *
   4 *  Copyright (c) 2010 Ignaz Forster <ignaz.forster@gmx.de>
   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/hid.h>
  25#include <linux/input.h>
  26#include <linux/module.h>
  27
  28#include "hid-ids.h"
  29
  30struct emsff_device {
  31        struct hid_report *report;
  32};
  33
  34static int emsff_play(struct input_dev *dev, void *data,
  35                         struct ff_effect *effect)
  36{
  37        struct hid_device *hid = input_get_drvdata(dev);
  38        struct emsff_device *emsff = data;
  39        int weak, strong;
  40
  41        weak = effect->u.rumble.weak_magnitude;
  42        strong = effect->u.rumble.strong_magnitude;
  43
  44        dbg_hid("called with 0x%04x 0x%04x\n", strong, weak);
  45
  46        weak = weak * 0xff / 0xffff;
  47        strong = strong * 0xff / 0xffff;
  48
  49        emsff->report->field[0]->value[1] = weak;
  50        emsff->report->field[0]->value[2] = strong;
  51
  52        dbg_hid("running with 0x%02x 0x%02x\n", strong, weak);
  53        hid_hw_request(hid, emsff->report, HID_REQ_SET_REPORT);
  54
  55        return 0;
  56}
  57
  58static int emsff_init(struct hid_device *hid)
  59{
  60        struct emsff_device *emsff;
  61        struct hid_report *report;
  62        struct hid_input *hidinput = list_first_entry(&hid->inputs,
  63                                                struct hid_input, list);
  64        struct list_head *report_list =
  65                        &hid->report_enum[HID_OUTPUT_REPORT].report_list;
  66        struct input_dev *dev = hidinput->input;
  67        int error;
  68
  69        if (list_empty(report_list)) {
  70                hid_err(hid, "no output reports found\n");
  71                return -ENODEV;
  72        }
  73
  74        report = list_first_entry(report_list, struct hid_report, list);
  75        if (report->maxfield < 1) {
  76                hid_err(hid, "no fields in the report\n");
  77                return -ENODEV;
  78        }
  79
  80        if (report->field[0]->report_count < 7) {
  81                hid_err(hid, "not enough values in the field\n");
  82                return -ENODEV;
  83        }
  84
  85        emsff = kzalloc(sizeof(struct emsff_device), GFP_KERNEL);
  86        if (!emsff)
  87                return -ENOMEM;
  88
  89        set_bit(FF_RUMBLE, dev->ffbit);
  90
  91        error = input_ff_create_memless(dev, emsff, emsff_play);
  92        if (error) {
  93                kfree(emsff);
  94                return error;
  95        }
  96
  97        emsff->report = report;
  98        emsff->report->field[0]->value[0] = 0x01;
  99        emsff->report->field[0]->value[1] = 0x00;
 100        emsff->report->field[0]->value[2] = 0x00;
 101        emsff->report->field[0]->value[3] = 0x00;
 102        emsff->report->field[0]->value[4] = 0x00;
 103        emsff->report->field[0]->value[5] = 0x00;
 104        emsff->report->field[0]->value[6] = 0x00;
 105        hid_hw_request(hid, emsff->report, HID_REQ_SET_REPORT);
 106
 107        hid_info(hid, "force feedback for EMS based devices by Ignaz Forster <ignaz.forster@gmx.de>\n");
 108
 109        return 0;
 110}
 111
 112static int ems_probe(struct hid_device *hdev, const struct hid_device_id *id)
 113{
 114        int ret;
 115
 116        ret = hid_parse(hdev);
 117        if (ret) {
 118                hid_err(hdev, "parse failed\n");
 119                goto err;
 120        }
 121
 122        ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT & ~HID_CONNECT_FF);
 123        if (ret) {
 124                hid_err(hdev, "hw start failed\n");
 125                goto err;
 126        }
 127
 128        ret = emsff_init(hdev);
 129        if (ret) {
 130                dev_err(&hdev->dev, "force feedback init failed\n");
 131                hid_hw_stop(hdev);
 132                goto err;
 133        }
 134
 135        return 0;
 136err:
 137        return ret;
 138}
 139
 140static const struct hid_device_id ems_devices[] = {
 141        { HID_USB_DEVICE(USB_VENDOR_ID_EMS, USB_DEVICE_ID_EMS_TRIO_LINKER_PLUS_II) },
 142        { }
 143};
 144MODULE_DEVICE_TABLE(hid, ems_devices);
 145
 146static struct hid_driver ems_driver = {
 147        .name = "hkems",
 148        .id_table = ems_devices,
 149        .probe = ems_probe,
 150};
 151module_hid_driver(ems_driver);
 152
 153MODULE_LICENSE("GPL");
 154
 155
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