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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * Force feedback support for EMS Trio Linker Plus II4 *5 * Copyright (c) 2010 Ignaz Forster <ignaz.forster@gmx.de>6 */7 8/*9 */10 11 12#include <linux/hid.h>13#include <linux/input.h>14#include <linux/module.h>15 16#include "hid-ids.h"17 18struct emsff_device {19 struct hid_report *report;20};21 22static int emsff_play(struct input_dev *dev, void *data,23 struct ff_effect *effect)24{25 struct hid_device *hid = input_get_drvdata(dev);26 struct emsff_device *emsff = data;27 int weak, strong;28 29 weak = effect->u.rumble.weak_magnitude;30 strong = effect->u.rumble.strong_magnitude;31 32 dbg_hid("called with 0x%04x 0x%04x\n", strong, weak);33 34 weak = weak * 0xff / 0xffff;35 strong = strong * 0xff / 0xffff;36 37 emsff->report->field[0]->value[1] = weak;38 emsff->report->field[0]->value[2] = strong;39 40 dbg_hid("running with 0x%02x 0x%02x\n", strong, weak);41 hid_hw_request(hid, emsff->report, HID_REQ_SET_REPORT);42 43 return 0;44}45 46static int emsff_init(struct hid_device *hid)47{48 struct emsff_device *emsff;49 struct hid_report *report;50 struct hid_input *hidinput;51 struct list_head *report_list =52 &hid->report_enum[HID_OUTPUT_REPORT].report_list;53 struct input_dev *dev;54 int error;55 56 if (list_empty(&hid->inputs)) {57 hid_err(hid, "no inputs found\n");58 return -ENODEV;59 }60 hidinput = list_first_entry(&hid->inputs, struct hid_input, list);61 dev = hidinput->input;62 63 if (list_empty(report_list)) {64 hid_err(hid, "no output reports found\n");65 return -ENODEV;66 }67 68 report = list_first_entry(report_list, struct hid_report, list);69 if (report->maxfield < 1) {70 hid_err(hid, "no fields in the report\n");71 return -ENODEV;72 }73 74 if (report->field[0]->report_count < 7) {75 hid_err(hid, "not enough values in the field\n");76 return -ENODEV;77 }78 79 emsff = kzalloc(sizeof(struct emsff_device), GFP_KERNEL);80 if (!emsff)81 return -ENOMEM;82 83 set_bit(FF_RUMBLE, dev->ffbit);84 85 error = input_ff_create_memless(dev, emsff, emsff_play);86 if (error) {87 kfree(emsff);88 return error;89 }90 91 emsff->report = report;92 emsff->report->field[0]->value[0] = 0x01;93 emsff->report->field[0]->value[1] = 0x00;94 emsff->report->field[0]->value[2] = 0x00;95 emsff->report->field[0]->value[3] = 0x00;96 emsff->report->field[0]->value[4] = 0x00;97 emsff->report->field[0]->value[5] = 0x00;98 emsff->report->field[0]->value[6] = 0x00;99 hid_hw_request(hid, emsff->report, HID_REQ_SET_REPORT);100 101 hid_info(hid, "force feedback for EMS based devices by Ignaz Forster <ignaz.forster@gmx.de>\n");102 103 return 0;104}105 106static int ems_probe(struct hid_device *hdev, const struct hid_device_id *id)107{108 int ret;109 110 ret = hid_parse(hdev);111 if (ret) {112 hid_err(hdev, "parse failed\n");113 goto err;114 }115 116 ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT & ~HID_CONNECT_FF);117 if (ret) {118 hid_err(hdev, "hw start failed\n");119 goto err;120 }121 122 ret = emsff_init(hdev);123 if (ret) {124 dev_err(&hdev->dev, "force feedback init failed\n");125 hid_hw_stop(hdev);126 goto err;127 }128 129 return 0;130err:131 return ret;132}133 134static const struct hid_device_id ems_devices[] = {135 { HID_USB_DEVICE(USB_VENDOR_ID_EMS, USB_DEVICE_ID_EMS_TRIO_LINKER_PLUS_II) },136 { }137};138MODULE_DEVICE_TABLE(hid, ems_devices);139 140static struct hid_driver ems_driver = {141 .name = "hkems",142 .id_table = ems_devices,143 .probe = ems_probe,144};145module_hid_driver(ems_driver);146 147MODULE_DESCRIPTION("Force feedback support for EMS Trio Linker Plus II");148MODULE_LICENSE("GPL");149 150