Quelle  hid-emsff.c   Sprache: C

// 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 \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_DESCRIPTION("Force feedback support for EMS Trio Linker Plus II");
MODULE_LICENSE("GPL");