/*
   *  Force feedback support for EMS Trio Linker Plus II
   *
   *  Copyright (c) 2010 Ignaz Forster <ignaz.forster@gmx.de>
   */
  
  /*
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation; either version 2 of the License, or
   * (at your option) any later version.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
   */
  
  
  #include <linux/hid.h>
  #include <linux/input.h>
  #include <linux/usb.h>

  #include <linux/module.h>

  
  #include "hid-ids.h"
  #include "usbhid/usbhid.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
  ", 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
  ", strong, weak);
  	usbhid_submit_report(hid, emsff->report, USB_DIR_OUT);
  
  	return 0;
  }
  
  static int emsff_init(struct hid_device *hid)
  {
  	struct emsff_device *emsff;
  	struct hid_report *report;
  	struct hid_input *hidinput = list_first_entry(&hid->inputs,
  						struct hid_input, list);
  	struct list_head *report_list =
  			&hid->report_enum[HID_OUTPUT_REPORT].report_list;
  	struct input_dev *dev = hidinput->input;
  	int error;
  
  	if (list_empty(report_list)) {

  		hid_err(hid, "no output reports found
  ");

  		return -ENODEV;
  	}
  
  	report = list_first_entry(report_list, struct hid_report, list);
  	if (report->maxfield < 1) {

  		hid_err(hid, "no fields in the report
  ");

  		return -ENODEV;
  	}
  
  	if (report->field[0]->report_count < 7) {

  		hid_err(hid, "not enough values in the field
  ");

  		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;
  	usbhid_submit_report(hid, emsff->report, USB_DIR_OUT);

  	hid_info(hid, "force feedback for EMS based devices by Ignaz Forster <ignaz.forster@gmx.de>
  ");

  
  	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
  ");

  		goto err;
  	}
  
  	ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT & ~HID_CONNECT_FF);
  	if (ret) {

  		hid_err(hdev, "hw start failed
  ");

  		goto err;
  	}

  	ret = emsff_init(hdev);
  	if (ret) {
  		dev_err(&hdev->dev, "force feedback init failed
  ");
  		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,
  };
  
  static int ems_init(void)
  {
  	return hid_register_driver(&ems_driver);
  }
  
  static void ems_exit(void)
  {
  	hid_unregister_driver(&ems_driver);
  }
  
  module_init(ems_init);
  module_exit(ems_exit);
  MODULE_LICENSE("GPL");