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 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 } 105 106 static 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; 130 err: 131 return ret; 132 } 133 134 static 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 }; 138 MODULE_DEVICE_TABLE(hid, ems_devices); 139 140 static struct hid_driver ems_driver = { 141 .name = "hkems", 142 .id_table = ems_devices, 143 .probe = ems_probe, 144 }; 145 module_hid_driver(ems_driver); 146 147 MODULE_LICENSE("GPL"); 148 149