1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Force feedback support for EMS Trio Linker Plus II 4 * 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 18 struct emsff_device { 19 struct hid_report *report; 20 }; 21 22 static 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 46 static int ems_input_configured(struct hid_device *hid, struct hid_input *hidinput) 47 { 48 struct emsff_device *emsff; 49 struct hid_report *report; 50 struct list_head *report_list = 51 &hid->report_enum[HID_OUTPUT_REPORT].report_list; 52 struct input_dev *dev = hidinput->input; 53 int error; 54 55 if (!list_is_first(&hidinput->list, &hid->inputs)) 56 return 0; 57 58 report = list_first_entry_or_null(report_list, struct hid_report, list); 59 if (!report) { 60 hid_err(hid, "no output reports found\n"); 61 return -ENODEV; 62 } 63 if (report->maxfield < 1) { 64 hid_err(hid, "no fields in the report\n"); 65 return -ENODEV; 66 } 67 68 if (report->field[0]->report_count < 7) { 69 hid_err(hid, "not enough values in the field\n"); 70 return -ENODEV; 71 } 72 73 emsff = kzalloc_obj(struct emsff_device); 74 if (!emsff) 75 return -ENOMEM; 76 77 emsff->report = report; 78 set_bit(FF_RUMBLE, dev->ffbit); 79 80 error = input_ff_create_memless(dev, emsff, emsff_play); 81 if (error) { 82 kfree(emsff); 83 return error; 84 } 85 86 emsff->report->field[0]->value[0] = 0x01; 87 emsff->report->field[0]->value[1] = 0x00; 88 emsff->report->field[0]->value[2] = 0x00; 89 emsff->report->field[0]->value[3] = 0x00; 90 emsff->report->field[0]->value[4] = 0x00; 91 emsff->report->field[0]->value[5] = 0x00; 92 emsff->report->field[0]->value[6] = 0x00; 93 hid_hw_request(hid, emsff->report, HID_REQ_SET_REPORT); 94 95 hid_info(hid, "force feedback for EMS based devices by Ignaz Forster <ignaz.forster@gmx.de>\n"); 96 97 return 0; 98 } 99 100 static const struct hid_device_id ems_devices[] = { 101 { HID_USB_DEVICE(USB_VENDOR_ID_EMS, USB_DEVICE_ID_EMS_TRIO_LINKER_PLUS_II) }, 102 { } 103 }; 104 MODULE_DEVICE_TABLE(hid, ems_devices); 105 106 static struct hid_driver ems_driver = { 107 .name = "hkems", 108 .id_table = ems_devices, 109 .input_configured = ems_input_configured, 110 }; 111 module_hid_driver(ems_driver); 112 113 MODULE_DESCRIPTION("Force feedback support for EMS Trio Linker Plus II"); 114 MODULE_LICENSE("GPL"); 115 116