// SPDX-License-Identifier: GPL-2.0-or-later /* * Force feedback support for EMS Trio Linker Plus II * * Copyright (c) 2010 Ignaz Forster <ignaz.forster@gmx.de> */ /* */ #include <linux/hid.h> #include <linux/input.h> #include <linux/module.h> #include "hid-ids.h" struct emsff_device { struct hid_report *report; }; static int emsff_play(struct input_dev *dev, void *data, struct ff_effect *effect) { struct hid_device *hid = input_get_drvdata(dev); struct emsff_device *emsff = data; int weak, strong; weak = effect->u.rumble.weak_magnitude; strong = effect->u.rumble.strong_magnitude; dbg_hid("called with 0x%04x 0x%04x\n", strong, weak); weak = weak * 0xff / 0xffff; strong = strong * 0xff / 0xffff; emsff->report->field[0]->value[1] = weak; emsff->report->field[0]->value[2] = strong; dbg_hid("running with 0x%02x 0x%02x\n", strong, weak); hid_hw_request(hid, emsff->report, HID_REQ_SET_REPORT); return 0; } static int emsff_init(struct hid_device *hid) { struct emsff_device *emsff; struct hid_report *report; struct hid_input *hidinput; struct list_head *report_list = &hid->report_enum[HID_OUTPUT_REPORT].report_list; struct input_dev *dev; int error; if (list_empty(&hid->inputs)) { hid_err(hid, "no inputs found\n"); return -ENODEV; } hidinput = list_first_entry(&hid->inputs, struct hid_input, list); dev = hidinput->input; if (list_empty(report_list)) { hid_err(hid, "no output reports found\n"); return -ENODEV; } report = list_first_entry(report_list, struct hid_report, list); if (report->maxfield < 1) { hid_err(hid, "no fields in the report\n"); return -ENODEV; } if (report->field[0]->report_count < 7) { hid_err(hid, "not enough values in the field\n"); return -ENODEV; } emsff = kzalloc(sizeof(struct emsff_device), GFP_KERNEL); if (!emsff) return -ENOMEM; set_bit(FF_RUMBLE, dev->ffbit); error = input_ff_create_memless(dev, emsff, emsff_play); if (error) { kfree(emsff); return error; } emsff->report = report; emsff->report->field[0]->value[0] = 0x01; emsff->report->field[0]->value[1] = 0x00; emsff->report->field[0]->value[2] = 0x00; emsff->report->field[0]->value[3] = 0x00; emsff->report->field[0]->value[4] = 0x00; emsff->report->field[0]->value[5] = 0x00; emsff->report->field[0]->value[6] = 0x00; hid_hw_request(hid, emsff->report, HID_REQ_SET_REPORT); hid_info(hid, "force feedback for EMS based devices by Ignaz Forster <ignaz.forster@gmx.de>\n"); return 0; } static int ems_probe(struct hid_device *hdev, const struct hid_device_id *id) { int ret; ret = hid_parse(hdev); if (ret) { hid_err(hdev, "parse failed\n"); goto err; } ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT & ~HID_CONNECT_FF); if (ret) { hid_err(hdev, "hw start failed\n"); goto err; } ret = emsff_init(hdev); if (ret) { dev_err(&hdev->dev, "force feedback init failed\n"); hid_hw_stop(hdev); goto err; } return 0; err: return ret; } static const struct hid_device_id ems_devices[] = { { HID_USB_DEVICE(USB_VENDOR_ID_EMS, USB_DEVICE_ID_EMS_TRIO_LINKER_PLUS_II) }, { } }; MODULE_DEVICE_TABLE(hid, ems_devices); static struct hid_driver ems_driver = { .name = "hkems", .id_table = ems_devices, .probe = ems_probe, }; module_hid_driver(ems_driver); MODULE_LICENSE("GPL");