// SPDX-License-Identifier: GPL-2.0-or-later

  /*
   *  HID driver for some a4tech "special" devices
   *
   *  Copyright (c) 1999 Andreas Gal
   *  Copyright (c) 2000-2005 Vojtech Pavlik <vojtech@suse.cz>
   *  Copyright (c) 2005 Michael Haboustak <mike-@cinci.rr.com> for Concept2, Inc
   *  Copyright (c) 2006-2007 Jiri Kosina

   *  Copyright (c) 2008 Jiri Slaby
   */
  
  /*

   */
  
  #include <linux/device.h>
  #include <linux/input.h>
  #include <linux/hid.h>
  #include <linux/module.h>

  #include <linux/slab.h>

  
  #include "hid-ids.h"
  
  #define A4_2WHEEL_MOUSE_HACK_7	0x01
  #define A4_2WHEEL_MOUSE_HACK_B8	0x02

  #define A4_WHEEL_ORIENTATION	(HID_UP_GENDESK | 0x000000b8)

  struct a4tech_sc {
  	unsigned long quirks;
  	unsigned int hw_wheel;
  	__s32 delayed_value;
  };

  static int a4_input_mapping(struct hid_device *hdev, struct hid_input *hi,
  			    struct hid_field *field, struct hid_usage *usage,
  			    unsigned long **bit, int *max)
  {
  	struct a4tech_sc *a4 = hid_get_drvdata(hdev);
  
  	if (a4->quirks & A4_2WHEEL_MOUSE_HACK_B8 &&
  	    usage->hid == A4_WHEEL_ORIENTATION) {
  		/*
  		 * We do not want to have this usage mapped to anything as it's
  		 * nonstandard and doesn't really behave like an HID report.
  		 * It's only selecting the orientation (vertical/horizontal) of
  		 * the previous mouse wheel report. The input_events will be
  		 * generated once both reports are recorded in a4_event().
  		 */
  		return -1;
  	}
  
  	return 0;
  
  }

  static int a4_input_mapped(struct hid_device *hdev, struct hid_input *hi,
  		struct hid_field *field, struct hid_usage *usage,
  		unsigned long **bit, int *max)
  {
  	struct a4tech_sc *a4 = hid_get_drvdata(hdev);

  	if (usage->type == EV_REL && usage->code == REL_WHEEL_HI_RES) {

  		set_bit(REL_HWHEEL, *bit);

  		set_bit(REL_HWHEEL_HI_RES, *bit);
  	}

  
  	if ((a4->quirks & A4_2WHEEL_MOUSE_HACK_7) && usage->hid == 0x00090007)
  		return -1;
  
  	return 0;
  }
  
  static int a4_event(struct hid_device *hdev, struct hid_field *field,
  		struct hid_usage *usage, __s32 value)
  {
  	struct a4tech_sc *a4 = hid_get_drvdata(hdev);
  	struct input_dev *input;

  	if (!(hdev->claimed & HID_CLAIMED_INPUT) || !field->hidinput)

  		return 0;
  
  	input = field->hidinput->input;
  
  	if (a4->quirks & A4_2WHEEL_MOUSE_HACK_B8) {

  		if (usage->type == EV_REL && usage->code == REL_WHEEL_HI_RES) {

  			a4->delayed_value = value;
  			return 1;
  		}

  		if (usage->hid == A4_WHEEL_ORIENTATION) {

  			input_event(input, EV_REL, value ? REL_HWHEEL :
  					REL_WHEEL, a4->delayed_value);

  			input_event(input, EV_REL, value ? REL_HWHEEL_HI_RES :
  					REL_WHEEL_HI_RES, a4->delayed_value * 120);

  			return 1;
  		}
  	}
  
  	if ((a4->quirks & A4_2WHEEL_MOUSE_HACK_7) && usage->hid == 0x00090007) {
  		a4->hw_wheel = !!value;
  		return 1;
  	}

  	if (usage->code == REL_WHEEL_HI_RES && a4->hw_wheel) {

  		input_event(input, usage->type, REL_HWHEEL, value);

  		input_event(input, usage->type, REL_HWHEEL_HI_RES, value * 120);

  		return 1;
  	}
  
  	return 0;
  }
  
  static int a4_probe(struct hid_device *hdev, const struct hid_device_id *id)
  {
  	struct a4tech_sc *a4;
  	int ret;

  	a4 = devm_kzalloc(&hdev->dev, sizeof(*a4), GFP_KERNEL);

  	if (a4 == NULL) {

  		hid_err(hdev, "can't alloc device descriptor
  ");

  		return -ENOMEM;

  	}
  
  	a4->quirks = id->driver_data;
  
  	hid_set_drvdata(hdev, a4);
  
  	ret = hid_parse(hdev);
  	if (ret) {

  		hid_err(hdev, "parse failed
  ");

  		return ret;

  	}

  	ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);

  	if (ret) {

  		hid_err(hdev, "hw start failed
  ");

  		return ret;

  	}
  
  	return 0;

  }
  
  static const struct hid_device_id a4_devices[] = {
  	{ HID_USB_DEVICE(USB_VENDOR_ID_A4TECH, USB_DEVICE_ID_A4TECH_WCP32PU),
  		.driver_data = A4_2WHEEL_MOUSE_HACK_7 },
  	{ HID_USB_DEVICE(USB_VENDOR_ID_A4TECH, USB_DEVICE_ID_A4TECH_X5_005D),
  		.driver_data = A4_2WHEEL_MOUSE_HACK_B8 },

  	{ HID_USB_DEVICE(USB_VENDOR_ID_A4TECH, USB_DEVICE_ID_A4TECH_RP_649),
  		.driver_data = A4_2WHEEL_MOUSE_HACK_B8 },

  	{ }
  };
  MODULE_DEVICE_TABLE(hid, a4_devices);
  
  static struct hid_driver a4_driver = {
  	.name = "a4tech",
  	.id_table = a4_devices,

  	.input_mapping = a4_input_mapping,

  	.input_mapped = a4_input_mapped,
  	.event = a4_event,
  	.probe = a4_probe,

  };

  module_hid_driver(a4_driver);

  MODULE_LICENSE("GPL");