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

  /*
   *  HID driver for multitouch panels
   *

   *  Copyright (c) 2010-2012 Stephane Chatty <chatty@enac.fr>

   *  Copyright (c) 2010-2013 Benjamin Tissoires <benjamin.tissoires@gmail.com>

   *  Copyright (c) 2010-2012 Ecole Nationale de l'Aviation Civile, France

   *  Copyright (c) 2012-2013 Red Hat, Inc

   *

   *  This code is partly based on hid-egalax.c:
   *
   *  Copyright (c) 2010 Stephane Chatty <chatty@enac.fr>
   *  Copyright (c) 2010 Henrik Rydberg <rydberg@euromail.se>
   *  Copyright (c) 2010 Canonical, Ltd.
   *

   *  This code is partly based on hid-3m-pct.c:
   *
   *  Copyright (c) 2009-2010 Stephane Chatty <chatty@enac.fr>
   *  Copyright (c) 2010      Henrik Rydberg <rydberg@euromail.se>
   *  Copyright (c) 2010      Canonical, Ltd.

   */
  
  /*

   */

  /*

   * This driver is regularly tested thanks to the test suite in hid-tools[1].

   * Please run these regression tests before patching this module so that
   * your patch won't break existing known devices.
   *

   * [1] https://gitlab.freedesktop.org/libevdev/hid-tools

   */

  #include <linux/device.h>
  #include <linux/hid.h>
  #include <linux/module.h>
  #include <linux/slab.h>

  #include <linux/input/mt.h>

  #include <linux/jiffies.h>

  #include <linux/string.h>

  #include <linux/timer.h>

  
  
  MODULE_AUTHOR("Stephane Chatty <chatty@enac.fr>");

  MODULE_AUTHOR("Benjamin Tissoires <benjamin.tissoires@gmail.com>");

  MODULE_DESCRIPTION("HID multitouch panels");
  MODULE_LICENSE("GPL");
  
  #include "hid-ids.h"
  
  /* quirks to control the device */

  #define MT_QUIRK_NOT_SEEN_MEANS_UP	BIT(0)
  #define MT_QUIRK_SLOT_IS_CONTACTID	BIT(1)
  #define MT_QUIRK_CYPRESS		BIT(2)
  #define MT_QUIRK_SLOT_IS_CONTACTNUMBER	BIT(3)
  #define MT_QUIRK_ALWAYS_VALID		BIT(4)
  #define MT_QUIRK_VALID_IS_INRANGE	BIT(5)
  #define MT_QUIRK_VALID_IS_CONFIDENCE	BIT(6)
  #define MT_QUIRK_CONFIDENCE		BIT(7)
  #define MT_QUIRK_SLOT_IS_CONTACTID_MINUS_ONE	BIT(8)
  #define MT_QUIRK_NO_AREA		BIT(9)
  #define MT_QUIRK_IGNORE_DUPLICATES	BIT(10)
  #define MT_QUIRK_HOVERING		BIT(11)
  #define MT_QUIRK_CONTACT_CNT_ACCURATE	BIT(12)
  #define MT_QUIRK_FORCE_GET_FEATURE	BIT(13)
  #define MT_QUIRK_FIX_CONST_CONTACT_ID	BIT(14)
  #define MT_QUIRK_TOUCH_SIZE_SCALING	BIT(15)

  #define MT_QUIRK_STICKY_FINGERS		BIT(16)

  #define MT_QUIRK_ASUS_CUSTOM_UP		BIT(17)

  #define MT_QUIRK_WIN8_PTP_BUTTONS	BIT(18)

  #define MT_QUIRK_SEPARATE_APP_REPORT	BIT(19)

  #define MT_QUIRK_FORCE_MULTI_INPUT	BIT(20)

  #define MT_INPUTMODE_TOUCHSCREEN	0x02
  #define MT_INPUTMODE_TOUCHPAD		0x03

  #define MT_BUTTONTYPE_CLICKPAD		0

  enum latency_mode {
  	HID_LATENCY_NORMAL = 0,
  	HID_LATENCY_HIGH = 1,
  };

  #define MT_IO_FLAGS_RUNNING		0

  #define MT_IO_FLAGS_ACTIVE_SLOTS	1
  #define MT_IO_FLAGS_PENDING_SLOTS	2

  static const bool mtrue = true;		/* default for true */
  static const bool mfalse;		/* default for false */
  static const __s32 mzero;		/* default for 0 */
  
  #define DEFAULT_TRUE	((void *)&mtrue)
  #define DEFAULT_FALSE	((void *)&mfalse)
  #define DEFAULT_ZERO	((void *)&mzero)
  
  struct mt_usages {
  	struct list_head list;
  	__s32 *x, *y, *cx, *cy, *p, *w, *h, *a;
  	__s32 *contactid;	/* the device ContactID assigned to this slot */
  	bool *tip_state;	/* is the touch valid? */
  	bool *inrange_state;	/* is the finger in proximity of the sensor? */
  	bool *confidence_state;	/* is the touch made by a finger? */

  };

  struct mt_application {
  	struct list_head list;
  	unsigned int application;

  	unsigned int report_id;

  	struct list_head mt_usages;	/* mt usages list */

  
  	__s32 quirks;

  	__s32 *scantime;		/* scantime reported */
  	__s32 scantime_logical_max;	/* max value for raw scantime */

  	__s32 *raw_cc;			/* contact count in the report */

  	int left_button_state;		/* left button state */
  	unsigned int mt_flags;		/* flags to pass to input-mt */

  	unsigned long *pending_palm_slots;	/* slots where we reported palm
  						 * and need to release */

  	__u8 num_received;	/* how many contacts we received */
  	__u8 num_expected;	/* expected last contact index */
  	__u8 buttons_count;	/* number of physical buttons per touchpad */
  	__u8 touches_by_report;	/* how many touches are present in one report:
  				 * 1 means we should use a serial protocol
  				 * > 1 means hybrid (multitouch) protocol
  				 */
  
  	__s32 dev_time;		/* the scan time provided by the device */
  	unsigned long jiffies;	/* the frame's jiffies */
  	int timestamp;		/* the timestamp to be sent */
  	int prev_scantime;		/* scantime reported previously */
  
  	bool have_contact_count;
  };

  struct mt_class {
  	__s32 name;	/* MT_CLS */
  	__s32 quirks;
  	__s32 sn_move;	/* Signal/noise ratio for move events */
  	__s32 sn_width;	/* Signal/noise ratio for width events */
  	__s32 sn_height;	/* Signal/noise ratio for height events */
  	__s32 sn_pressure;	/* Signal/noise ratio for pressure events */
  	__u8 maxcontacts;

  	bool is_indirect;	/* true for touchpads */

  	bool export_all_inputs;	/* do not ignore mouse, keyboards, etc... */

  };

  struct mt_report_data {
  	struct list_head list;
  	struct hid_report *report;
  	struct mt_application *application;
  	bool is_mt_collection;
  };

  struct mt_device {

  	struct mt_class mtclass;	/* our mt device class */

  	struct timer_list release_timer;	/* to release sticky fingers */

  	struct hid_device *hdev;	/* hid_device we're attached to */

  	unsigned long mt_io_flags;	/* mt flags (MT_IO_FLAGS_*) */

  	__u8 inputmode_value;	/* InputMode HID feature value */

  	__u8 maxcontacts;

  	bool is_buttonpad;	/* is this device a button pad? */

  	bool serial_maybe;	/* need to check for serial protocol */

  
  	struct list_head applications;

  	struct list_head reports;

  };

  static void mt_post_parse_default_settings(struct mt_device *td,
  					   struct mt_application *app);
  static void mt_post_parse(struct mt_device *td, struct mt_application *app);

  /* classes of device behavior */

  #define MT_CLS_DEFAULT				0x0001

  #define MT_CLS_SERIAL				0x0002
  #define MT_CLS_CONFIDENCE			0x0003

  #define MT_CLS_CONFIDENCE_CONTACT_ID		0x0004
  #define MT_CLS_CONFIDENCE_MINUS_ONE		0x0005
  #define MT_CLS_DUAL_INRANGE_CONTACTID		0x0006
  #define MT_CLS_DUAL_INRANGE_CONTACTNUMBER	0x0007

  /* reserved					0x0008 */

  #define MT_CLS_INRANGE_CONTACTNUMBER		0x0009

  #define MT_CLS_NSMU				0x000a

  /* reserved					0x0010 */
  /* reserved					0x0011 */

  #define MT_CLS_WIN_8				0x0012

  #define MT_CLS_EXPORT_ALL_INPUTS		0x0013

  /* reserved					0x0014 */

  #define MT_CLS_WIN_8_FORCE_MULTI_INPUT		0x0015

  
  /* vendor specific classes */
  #define MT_CLS_3M				0x0101

  /* reserved					0x0102 */

  #define MT_CLS_EGALAX				0x0103

  #define MT_CLS_EGALAX_SERIAL			0x0104

  #define MT_CLS_TOPSEED				0x0105

  #define MT_CLS_PANASONIC			0x0106

  #define MT_CLS_FLATFROG				0x0107

  #define MT_CLS_GENERALTOUCH_TWOFINGERS		0x0108
  #define MT_CLS_GENERALTOUCH_PWT_TENFINGERS	0x0109

  #define MT_CLS_LG				0x010a

  #define MT_CLS_ASUS				0x010b

  #define MT_CLS_VTL				0x0110

  #define MT_CLS_GOOGLE				0x0111

  #define MT_CLS_RAZER_BLADE_STEALTH		0x0112

  #define MT_CLS_SMART_TECH			0x0113

  #define MT_DEFAULT_MAXCONTACT	10

  #define MT_MAX_MAXCONTACT	250

  /*
   * Resync device and local timestamps after that many microseconds without
   * receiving data.
   */
  #define MAX_TIMESTAMP_INTERVAL	1000000

  #define MT_USB_DEVICE(v, p)	HID_DEVICE(BUS_USB, HID_GROUP_MULTITOUCH, v, p)
  #define MT_BT_DEVICE(v, p)	HID_DEVICE(BUS_BLUETOOTH, HID_GROUP_MULTITOUCH, v, p)

  /*
   * these device-dependent functions determine what slot corresponds
   * to a valid contact that was just read.
   */

  static int cypress_compute_slot(struct mt_application *application,
  				struct mt_usages *slot)

  {

  	if (*slot->contactid != 0 || application->num_received == 0)
  		return *slot->contactid;

  	else
  		return -1;
  }

  static const struct mt_class mt_classes[] = {

  	{ .name = MT_CLS_DEFAULT,

  		.quirks = MT_QUIRK_ALWAYS_VALID |
  			MT_QUIRK_CONTACT_CNT_ACCURATE },
  	{ .name = MT_CLS_NSMU,

  		.quirks = MT_QUIRK_NOT_SEEN_MEANS_UP },

  	{ .name = MT_CLS_SERIAL,
  		.quirks = MT_QUIRK_ALWAYS_VALID},

  	{ .name = MT_CLS_CONFIDENCE,
  		.quirks = MT_QUIRK_VALID_IS_CONFIDENCE },

  	{ .name = MT_CLS_CONFIDENCE_CONTACT_ID,
  		.quirks = MT_QUIRK_VALID_IS_CONFIDENCE |
  			MT_QUIRK_SLOT_IS_CONTACTID },

  	{ .name = MT_CLS_CONFIDENCE_MINUS_ONE,
  		.quirks = MT_QUIRK_VALID_IS_CONFIDENCE |
  			MT_QUIRK_SLOT_IS_CONTACTID_MINUS_ONE },

  	{ .name = MT_CLS_DUAL_INRANGE_CONTACTID,

  		.quirks = MT_QUIRK_VALID_IS_INRANGE |
  			MT_QUIRK_SLOT_IS_CONTACTID,
  		.maxcontacts = 2 },

  	{ .name = MT_CLS_DUAL_INRANGE_CONTACTNUMBER,

  		.quirks = MT_QUIRK_VALID_IS_INRANGE |
  			MT_QUIRK_SLOT_IS_CONTACTNUMBER,
  		.maxcontacts = 2 },

  	{ .name = MT_CLS_INRANGE_CONTACTNUMBER,
  		.quirks = MT_QUIRK_VALID_IS_INRANGE |
  			MT_QUIRK_SLOT_IS_CONTACTNUMBER },

  	{ .name = MT_CLS_WIN_8,
  		.quirks = MT_QUIRK_ALWAYS_VALID |
  			MT_QUIRK_IGNORE_DUPLICATES |
  			MT_QUIRK_HOVERING |

  			MT_QUIRK_CONTACT_CNT_ACCURATE |

  			MT_QUIRK_STICKY_FINGERS |

  			MT_QUIRK_WIN8_PTP_BUTTONS,
  		.export_all_inputs = true },

  	{ .name = MT_CLS_EXPORT_ALL_INPUTS,
  		.quirks = MT_QUIRK_ALWAYS_VALID |
  			MT_QUIRK_CONTACT_CNT_ACCURATE,
  		.export_all_inputs = true },

  	{ .name = MT_CLS_WIN_8_FORCE_MULTI_INPUT,
  		.quirks = MT_QUIRK_ALWAYS_VALID |
  			MT_QUIRK_IGNORE_DUPLICATES |
  			MT_QUIRK_HOVERING |
  			MT_QUIRK_CONTACT_CNT_ACCURATE |
  			MT_QUIRK_STICKY_FINGERS |
  			MT_QUIRK_WIN8_PTP_BUTTONS |
  			MT_QUIRK_FORCE_MULTI_INPUT,
  		.export_all_inputs = true },

  
  	/*
  	 * vendor specific classes
  	 */
  	{ .name = MT_CLS_3M,
  		.quirks = MT_QUIRK_VALID_IS_CONFIDENCE |

  			MT_QUIRK_SLOT_IS_CONTACTID |
  			MT_QUIRK_TOUCH_SIZE_SCALING,

  		.sn_move = 2048,
  		.sn_width = 128,

  		.sn_height = 128,
  		.maxcontacts = 60,
  	},

  	{ .name = MT_CLS_EGALAX,
  		.quirks =  MT_QUIRK_SLOT_IS_CONTACTID |

  			MT_QUIRK_VALID_IS_INRANGE,

  		.sn_move = 4096,
  		.sn_pressure = 32,
  	},

  	{ .name = MT_CLS_EGALAX_SERIAL,
  		.quirks =  MT_QUIRK_SLOT_IS_CONTACTID |
  			MT_QUIRK_ALWAYS_VALID,

  		.sn_move = 4096,
  		.sn_pressure = 32,
  	},

  	{ .name = MT_CLS_TOPSEED,
  		.quirks = MT_QUIRK_ALWAYS_VALID,
  		.is_indirect = true,
  		.maxcontacts = 2,
  	},

  	{ .name = MT_CLS_PANASONIC,
  		.quirks = MT_QUIRK_NOT_SEEN_MEANS_UP,
  		.maxcontacts = 4 },

  	{ .name	= MT_CLS_GENERALTOUCH_TWOFINGERS,
  		.quirks	= MT_QUIRK_NOT_SEEN_MEANS_UP |
  			MT_QUIRK_VALID_IS_INRANGE |

  			MT_QUIRK_SLOT_IS_CONTACTID,

  		.maxcontacts = 2
  	},
  	{ .name	= MT_CLS_GENERALTOUCH_PWT_TENFINGERS,
  		.quirks	= MT_QUIRK_NOT_SEEN_MEANS_UP |

  			MT_QUIRK_SLOT_IS_CONTACTID

  	},

  	{ .name = MT_CLS_FLATFROG,
  		.quirks = MT_QUIRK_NOT_SEEN_MEANS_UP |
  			MT_QUIRK_NO_AREA,
  		.sn_move = 2048,
  		.maxcontacts = 40,
  	},

  	{ .name = MT_CLS_LG,
  		.quirks = MT_QUIRK_ALWAYS_VALID |
  			MT_QUIRK_FIX_CONST_CONTACT_ID |
  			MT_QUIRK_IGNORE_DUPLICATES |
  			MT_QUIRK_HOVERING |
  			MT_QUIRK_CONTACT_CNT_ACCURATE },

  	{ .name = MT_CLS_ASUS,
  		.quirks = MT_QUIRK_ALWAYS_VALID |
  			MT_QUIRK_CONTACT_CNT_ACCURATE |
  			MT_QUIRK_ASUS_CUSTOM_UP },

  	{ .name = MT_CLS_VTL,
  		.quirks = MT_QUIRK_ALWAYS_VALID |
  			MT_QUIRK_CONTACT_CNT_ACCURATE |
  			MT_QUIRK_FORCE_GET_FEATURE,
  	},

  	{ .name = MT_CLS_GOOGLE,
  		.quirks = MT_QUIRK_ALWAYS_VALID |
  			MT_QUIRK_CONTACT_CNT_ACCURATE |
  			MT_QUIRK_SLOT_IS_CONTACTID |
  			MT_QUIRK_HOVERING
  	},

  	{ .name = MT_CLS_RAZER_BLADE_STEALTH,
  		.quirks = MT_QUIRK_ALWAYS_VALID |
  			MT_QUIRK_IGNORE_DUPLICATES |
  			MT_QUIRK_HOVERING |
  			MT_QUIRK_CONTACT_CNT_ACCURATE |
  			MT_QUIRK_WIN8_PTP_BUTTONS,
  	},

  	{ .name = MT_CLS_SMART_TECH,
  		.quirks = MT_QUIRK_ALWAYS_VALID |
  			MT_QUIRK_IGNORE_DUPLICATES |
  			MT_QUIRK_CONTACT_CNT_ACCURATE |
  			MT_QUIRK_SEPARATE_APP_REPORT,
  	},

  	{ }

  };

  static ssize_t mt_show_quirks(struct device *dev,
  			   struct device_attribute *attr,
  			   char *buf)
  {

  	struct hid_device *hdev = to_hid_device(dev);

  	struct mt_device *td = hid_get_drvdata(hdev);
  
  	return sprintf(buf, "%u
  ", td->mtclass.quirks);
  }
  
  static ssize_t mt_set_quirks(struct device *dev,
  			  struct device_attribute *attr,
  			  const char *buf, size_t count)
  {

  	struct hid_device *hdev = to_hid_device(dev);

  	struct mt_device *td = hid_get_drvdata(hdev);

  	struct mt_application *application;

  
  	unsigned long val;
  
  	if (kstrtoul(buf, 0, &val))
  		return -EINVAL;
  
  	td->mtclass.quirks = val;

  	list_for_each_entry(application, &td->applications, list) {

  		application->quirks = val;
  		if (!application->have_contact_count)
  			application->quirks &= ~MT_QUIRK_CONTACT_CNT_ACCURATE;

  	}

  	return count;
  }
  
  static DEVICE_ATTR(quirks, S_IWUSR | S_IRUGO, mt_show_quirks, mt_set_quirks);
  
  static struct attribute *sysfs_attrs[] = {
  	&dev_attr_quirks.attr,
  	NULL
  };

  static const struct attribute_group mt_attribute_group = {

  	.attrs = sysfs_attrs
  };

  static void mt_get_feature(struct hid_device *hdev, struct hid_report *report)
  {

  	int ret;
  	u32 size = hid_report_len(report);

  	u8 *buf;
  
  	/*

  	 * Do not fetch the feature report if the device has been explicitly
  	 * marked as non-capable.

  	 */

  	if (hdev->quirks & HID_QUIRK_NO_INIT_REPORTS)

  		return;
  
  	buf = hid_alloc_report_buf(report, GFP_KERNEL);
  	if (!buf)
  		return;
  
  	ret = hid_hw_raw_request(hdev, report->id, buf, size,
  				 HID_FEATURE_REPORT, HID_REQ_GET_REPORT);
  	if (ret < 0) {
  		dev_warn(&hdev->dev, "failed to fetch feature %d
  ",
  			 report->id);
  	} else {
  		ret = hid_report_raw_event(hdev, HID_FEATURE_REPORT, buf,
  					   size, 0);
  		if (ret)
  			dev_warn(&hdev->dev, "failed to report feature
  ");
  	}
  
  	kfree(buf);
  }

  static void mt_feature_mapping(struct hid_device *hdev,

  		struct hid_field *field, struct hid_usage *usage)
  {

  	struct mt_device *td = hid_get_drvdata(hdev);
  
  	switch (usage->hid) {

  	case HID_DG_CONTACTMAX:

  		mt_get_feature(hdev, field->report);

  		td->maxcontacts = field->value[0];

  		if (!td->maxcontacts &&
  		    field->logical_maximum <= MT_MAX_MAXCONTACT)
  			td->maxcontacts = field->logical_maximum;

  		if (td->mtclass.maxcontacts)

  			/* check if the maxcontacts is given by the class */

  			td->maxcontacts = td->mtclass.maxcontacts;

  
  		break;

  	case HID_DG_BUTTONTYPE:
  		if (usage->usage_index >= field->report_count) {
  			dev_err(&hdev->dev, "HID_DG_BUTTONTYPE out of range
  ");
  			break;
  		}

  		mt_get_feature(hdev, field->report);

  		if (field->value[usage->usage_index] == MT_BUTTONTYPE_CLICKPAD)
  			td->is_buttonpad = true;
  
  		break;

  	case 0xff0000c5:
  		/* Retrieve the Win8 blob once to enable some devices */
  		if (usage->usage_index == 0)
  			mt_get_feature(hdev, field->report);
  		break;

  	}
  }
  
  static void set_abs(struct input_dev *input, unsigned int code,
  		struct hid_field *field, int snratio)
  {
  	int fmin = field->logical_minimum;
  	int fmax = field->logical_maximum;
  	int fuzz = snratio ? (fmax - fmin) / snratio : 0;
  	input_set_abs_params(input, code, fmin, fmax, fuzz, 0);

  	input_abs_set_res(input, code, hidinput_calc_abs_res(field, code));

  }

  static struct mt_usages *mt_allocate_usage(struct hid_device *hdev,
  					   struct mt_application *application)
  {
  	struct mt_usages *usage;
  
  	usage = devm_kzalloc(&hdev->dev, sizeof(*usage), GFP_KERNEL);
  	if (!usage)
  		return NULL;
  
  	/* set some defaults so we do not need to check for null pointers */
  	usage->x = DEFAULT_ZERO;
  	usage->y = DEFAULT_ZERO;
  	usage->cx = DEFAULT_ZERO;
  	usage->cy = DEFAULT_ZERO;
  	usage->p = DEFAULT_ZERO;
  	usage->w = DEFAULT_ZERO;
  	usage->h = DEFAULT_ZERO;
  	usage->a = DEFAULT_ZERO;
  	usage->contactid = DEFAULT_ZERO;
  	usage->tip_state = DEFAULT_FALSE;
  	usage->inrange_state = DEFAULT_FALSE;
  	usage->confidence_state = DEFAULT_TRUE;
  
  	list_add_tail(&usage->list, &application->mt_usages);
  
  	return usage;
  }

  static struct mt_application *mt_allocate_application(struct mt_device *td,

  						      struct hid_report *report)

  {

  	unsigned int application = report->application;

  	struct mt_application *mt_application;
  
  	mt_application = devm_kzalloc(&td->hdev->dev, sizeof(*mt_application),
  				      GFP_KERNEL);
  	if (!mt_application)
  		return NULL;
  
  	mt_application->application = application;

  	INIT_LIST_HEAD(&mt_application->mt_usages);

  
  	if (application == HID_DG_TOUCHSCREEN)
  		mt_application->mt_flags |= INPUT_MT_DIRECT;
  
  	/*
  	 * Model touchscreens providing buttons as touchpads.
  	 */
  	if (application == HID_DG_TOUCHPAD) {
  		mt_application->mt_flags |= INPUT_MT_POINTER;
  		td->inputmode_value = MT_INPUTMODE_TOUCHPAD;
  	}

  	mt_application->scantime = DEFAULT_ZERO;
  	mt_application->raw_cc = DEFAULT_ZERO;

  	mt_application->quirks = td->mtclass.quirks;

  	mt_application->report_id = report->id;

  
  	list_add_tail(&mt_application->list, &td->applications);
  
  	return mt_application;
  }
  
  static struct mt_application *mt_find_application(struct mt_device *td,

  						  struct hid_report *report)

  {

  	unsigned int application = report->application;

  	struct mt_application *tmp, *mt_application = NULL;
  
  	list_for_each_entry(tmp, &td->applications, list) {
  		if (application == tmp->application) {

  			if (!(td->mtclass.quirks & MT_QUIRK_SEPARATE_APP_REPORT) ||
  			    tmp->report_id == report->id) {
  				mt_application = tmp;
  				break;
  			}

  		}
  	}
  
  	if (!mt_application)

  		mt_application = mt_allocate_application(td, report);

  
  	return mt_application;
  }

  static struct mt_report_data *mt_allocate_report_data(struct mt_device *td,
  						      struct hid_report *report)
  {
  	struct mt_report_data *rdata;
  	struct hid_field *field;
  	int r, n;
  
  	rdata = devm_kzalloc(&td->hdev->dev, sizeof(*rdata), GFP_KERNEL);
  	if (!rdata)
  		return NULL;
  
  	rdata->report = report;

  	rdata->application = mt_find_application(td, report);

  
  	if (!rdata->application) {
  		devm_kfree(&td->hdev->dev, rdata);
  		return NULL;
  	}
  
  	for (r = 0; r < report->maxfield; r++) {
  		field = report->field[r];
  
  		if (!(HID_MAIN_ITEM_VARIABLE & field->flags))
  			continue;
  
  		for (n = 0; n < field->report_count; n++) {
  			if (field->usage[n].hid == HID_DG_CONTACTID)
  				rdata->is_mt_collection = true;
  		}
  	}
  
  	list_add_tail(&rdata->list, &td->reports);
  
  	return rdata;
  }
  
  static struct mt_report_data *mt_find_report_data(struct mt_device *td,
  						  struct hid_report *report)
  {
  	struct mt_report_data *tmp, *rdata = NULL;
  
  	list_for_each_entry(tmp, &td->reports, list) {
  		if (report == tmp->report) {
  			rdata = tmp;
  			break;
  		}
  	}
  
  	if (!rdata)
  		rdata = mt_allocate_report_data(td, report);
  
  	return rdata;
  }

  static void mt_store_field(struct hid_device *hdev,
  			   struct mt_application *application,
  			   __s32 *value,
  			   size_t offset)

  {

  	struct mt_usages *usage;
  	__s32 **target;
  
  	if (list_empty(&application->mt_usages))
  		usage = mt_allocate_usage(hdev, application);
  	else
  		usage = list_last_entry(&application->mt_usages,
  					struct mt_usages,
  					list);

  	if (!usage)

  		return;

  	target = (__s32 **)((char *)usage + offset);
  
  	/* the value has already been filled, create a new slot */
  	if (*target != DEFAULT_TRUE &&
  	    *target != DEFAULT_FALSE &&
  	    *target != DEFAULT_ZERO) {

  		if (usage->contactid == DEFAULT_ZERO ||
  		    usage->x == DEFAULT_ZERO ||
  		    usage->y == DEFAULT_ZERO) {
  			hid_dbg(hdev,
  				"ignoring duplicate usage on incomplete");
  			return;
  		}

  		usage = mt_allocate_usage(hdev, application);
  		if (!usage)
  			return;
  
  		target = (__s32 **)((char *)usage + offset);
  	}
  
  	*target = value;

  }

  #define MT_STORE_FIELD(__name)						\
  	mt_store_field(hdev, app,					\
  		       &field->value[usage->usage_index],		\
  		       offsetof(struct mt_usages, __name))

  static int mt_touch_input_mapping(struct hid_device *hdev, struct hid_input *hi,

  		struct hid_field *field, struct hid_usage *usage,

  		unsigned long **bit, int *max, struct mt_application *app)

  {
  	struct mt_device *td = hid_get_drvdata(hdev);

  	struct mt_class *cls = &td->mtclass;

  	int code;

  	struct hid_usage *prev_usage = NULL;

  	/*
  	 * Model touchscreens providing buttons as touchpads.

  	 */

  	if (field->application == HID_DG_TOUCHSCREEN &&
  	    (usage->hid & HID_USAGE_PAGE) == HID_UP_BUTTON) {

  		app->mt_flags |= INPUT_MT_POINTER;

  		td->inputmode_value = MT_INPUTMODE_TOUCHPAD;
  	}

  	/* count the buttons on touchpads */
  	if ((usage->hid & HID_USAGE_PAGE) == HID_UP_BUTTON)

  		app->buttons_count++;

  	if (usage->usage_index)
  		prev_usage = &field->usage[usage->usage_index - 1];

  	switch (usage->hid & HID_USAGE_PAGE) {
  
  	case HID_UP_GENDESK:
  		switch (usage->hid) {
  		case HID_GD_X:

  			if (prev_usage && (prev_usage->hid == usage->hid)) {

  				code = ABS_MT_TOOL_X;

  				MT_STORE_FIELD(cx);
  			} else {

  				code = ABS_MT_POSITION_X;

  				MT_STORE_FIELD(x);
  			}

  			set_abs(hi->input, code, field, cls->sn_move);

  			/*
  			 * A system multi-axis that exports X and Y has a high
  			 * chance of being used directly on a surface
  			 */
  			if (field->application == HID_GD_SYSTEM_MULTIAXIS) {
  				__set_bit(INPUT_PROP_DIRECT,
  					  hi->input->propbit);
  				input_set_abs_params(hi->input,
  						     ABS_MT_TOOL_TYPE,
  						     MT_TOOL_DIAL,
  						     MT_TOOL_DIAL, 0, 0);
  			}

  			return 1;
  		case HID_GD_Y:

  			if (prev_usage && (prev_usage->hid == usage->hid)) {

  				code = ABS_MT_TOOL_Y;

  				MT_STORE_FIELD(cy);
  			} else {

  				code = ABS_MT_POSITION_Y;

  				MT_STORE_FIELD(y);
  			}

  			set_abs(hi->input, code, field, cls->sn_move);

  			return 1;
  		}
  		return 0;
  
  	case HID_UP_DIGITIZER:
  		switch (usage->hid) {
  		case HID_DG_INRANGE:

  			if (app->quirks & MT_QUIRK_HOVERING) {

  				input_set_abs_params(hi->input,
  					ABS_MT_DISTANCE, 0, 1, 0, 0);
  			}

  			MT_STORE_FIELD(inrange_state);

  			return 1;
  		case HID_DG_CONFIDENCE:

  			if (cls->name == MT_CLS_WIN_8 &&

  				(field->application == HID_DG_TOUCHPAD ||
  				 field->application == HID_DG_TOUCHSCREEN))

  				app->quirks |= MT_QUIRK_CONFIDENCE;

  
  			if (app->quirks & MT_QUIRK_CONFIDENCE)
  				input_set_abs_params(hi->input,
  						     ABS_MT_TOOL_TYPE,
  						     MT_TOOL_FINGER,
  						     MT_TOOL_PALM, 0, 0);

  			MT_STORE_FIELD(confidence_state);

  			return 1;
  		case HID_DG_TIPSWITCH:

  			if (field->application != HID_GD_SYSTEM_MULTIAXIS)
  				input_set_capability(hi->input,
  						     EV_KEY, BTN_TOUCH);

  			MT_STORE_FIELD(tip_state);

  			return 1;
  		case HID_DG_CONTACTID:

  			MT_STORE_FIELD(contactid);

  			app->touches_by_report++;

  			return 1;
  		case HID_DG_WIDTH:

  			if (!(app->quirks & MT_QUIRK_NO_AREA))

  				set_abs(hi->input, ABS_MT_TOUCH_MAJOR, field,
  					cls->sn_width);

  			MT_STORE_FIELD(w);

  			return 1;
  		case HID_DG_HEIGHT:

  			if (!(app->quirks & MT_QUIRK_NO_AREA)) {

  				set_abs(hi->input, ABS_MT_TOUCH_MINOR, field,
  					cls->sn_height);

  
  				/*
  				 * Only set ABS_MT_ORIENTATION if it is not
  				 * already set by the HID_DG_AZIMUTH usage.
  				 */
  				if (!test_bit(ABS_MT_ORIENTATION,
  						hi->input->absbit))
  					input_set_abs_params(hi->input,
  						ABS_MT_ORIENTATION, 0, 1, 0, 0);

  			}

  			MT_STORE_FIELD(h);

  			return 1;
  		case HID_DG_TIPPRESSURE:

  			set_abs(hi->input, ABS_MT_PRESSURE, field,
  				cls->sn_pressure);

  			MT_STORE_FIELD(p);

  			return 1;

  		case HID_DG_SCANTIME:

  			input_set_capability(hi->input, EV_MSC, MSC_TIMESTAMP);

  			app->scantime = &field->value[usage->usage_index];
  			app->scantime_logical_max = field->logical_maximum;

  			return 1;

  		case HID_DG_CONTACTCOUNT:

  			app->have_contact_count = true;
  			app->raw_cc = &field->value[usage->usage_index];

  			return 1;

  		case HID_DG_AZIMUTH:

  			/*
  			 * Azimuth has the range of [0, MAX) representing a full
  			 * revolution. Set ABS_MT_ORIENTATION to a quarter of
  			 * MAX according the definition of ABS_MT_ORIENTATION
  			 */
  			input_set_abs_params(hi->input, ABS_MT_ORIENTATION,
  				-field->logical_maximum / 4,
  				field->logical_maximum / 4,
  				cls->sn_move ?
  				field->logical_maximum / cls->sn_move : 0, 0);

  			MT_STORE_FIELD(a);

  			return 1;

  		case HID_DG_CONTACTMAX:

  			/* contact max are global to the report */

  			return -1;

  		case HID_DG_TOUCH:
  			/* Legacy devices use TIPSWITCH and not TOUCH.
  			 * Let's just ignore this field. */
  			return -1;

  		}

  		/* let hid-input decide for the others */
  		return 0;

  	case HID_UP_BUTTON:
  		code = BTN_MOUSE + ((usage->hid - 1) & HID_USAGE);

  		/*
  		 * MS PTP spec says that external buttons left and right have
  		 * usages 2 and 3.
  		 */

  		if ((app->quirks & MT_QUIRK_WIN8_PTP_BUTTONS) &&

  		    field->application == HID_DG_TOUCHPAD &&
  		    (usage->hid & HID_USAGE) > 1)
  			code--;

  
  		if (field->application == HID_GD_SYSTEM_MULTIAXIS)
  			code = BTN_0  + ((usage->hid - 1) & HID_USAGE);

  		hid_map_usage(hi, usage, bit, max, EV_KEY, code);

  		if (!*bit)
  			return -1;

  		input_set_capability(hi->input, EV_KEY, code);
  		return 1;

  	case 0xff000000:
  		/* we do not want to map these: no input-oriented meaning */
  		return -1;
  	}
  
  	return 0;
  }

  static int mt_compute_slot(struct mt_device *td, struct mt_application *app,

  			   struct mt_usages *slot,

  			   struct input_dev *input)

  {

  	__s32 quirks = app->quirks;

  	if (quirks & MT_QUIRK_SLOT_IS_CONTACTID)

  		return *slot->contactid;

  	if (quirks & MT_QUIRK_CYPRESS)

  		return cypress_compute_slot(app, slot);

  	if (quirks & MT_QUIRK_SLOT_IS_CONTACTNUMBER)

  		return app->num_received;

  	if (quirks & MT_QUIRK_SLOT_IS_CONTACTID_MINUS_ONE)

  		return *slot->contactid - 1;

  	return input_mt_get_slot_by_key(input, *slot->contactid);

  }

  static void mt_release_pending_palms(struct mt_device *td,
  				     struct mt_application *app,
  				     struct input_dev *input)
  {
  	int slotnum;
  	bool need_sync = false;
  
  	for_each_set_bit(slotnum, app->pending_palm_slots, td->maxcontacts) {
  		clear_bit(slotnum, app->pending_palm_slots);
  
  		input_mt_slot(input, slotnum);

  		input_mt_report_slot_inactive(input);

  
  		need_sync = true;
  	}
  
  	if (need_sync) {
  		input_mt_sync_frame(input);
  		input_sync(input);
  	}
  }

  /*
   * this function is called when a whole packet has been received and processed,
   * so that it can decide what to send to the input layer.
   */

  static void mt_sync_frame(struct mt_device *td, struct mt_application *app,
  			  struct input_dev *input)

  {

  	if (app->quirks & MT_QUIRK_WIN8_PTP_BUTTONS)

  		input_event(input, EV_KEY, BTN_LEFT, app->left_button_state);

  	input_mt_sync_frame(input);

  	input_event(input, EV_MSC, MSC_TIMESTAMP, app->timestamp);

  	input_sync(input);

  
  	mt_release_pending_palms(td, app, input);

  	app->num_received = 0;
  	app->left_button_state = 0;

  	if (test_bit(MT_IO_FLAGS_ACTIVE_SLOTS, &td->mt_io_flags))
  		set_bit(MT_IO_FLAGS_PENDING_SLOTS, &td->mt_io_flags);
  	else
  		clear_bit(MT_IO_FLAGS_PENDING_SLOTS, &td->mt_io_flags);
  	clear_bit(MT_IO_FLAGS_ACTIVE_SLOTS, &td->mt_io_flags);

  }

  static int mt_compute_timestamp(struct mt_application *app, __s32 value)

  {

  	long delta = value - app->prev_scantime;
  	unsigned long jdelta = jiffies_to_usecs(jiffies - app->jiffies);

  	app->jiffies = jiffies;

  
  	if (delta < 0)

  		delta += app->scantime_logical_max;

  
  	/* HID_DG_SCANTIME is expressed in 100us, we want it in us. */
  	delta *= 100;
  
  	if (jdelta > MAX_TIMESTAMP_INTERVAL)
  		/* No data received for a while, resync the timestamp. */
  		return 0;
  	else

  		return app->timestamp + delta;

  }

  static int mt_touch_event(struct hid_device *hid, struct hid_field *field,

  				struct hid_usage *usage, __s32 value)
  {

  	/* we will handle the hidinput part later, now remains hiddev */
  	if (hid->claimed & HID_CLAIMED_HIDDEV && hid->hiddev_hid_event)
  		hid->hiddev_hid_event(hid, field, usage, value);
  
  	return 1;
  }

  static int mt_process_slot(struct mt_device *td, struct input_dev *input,
  			    struct mt_application *app,
  			    struct mt_usages *slot)

  {

  	struct input_mt *mt = input->mt;

  	__s32 quirks = app->quirks;

  	bool valid = true;
  	bool confidence_state = true;
  	bool inrange_state = false;
  	int active;
  	int slotnum;

  	int tool = MT_TOOL_FINGER;

  	if (!slot)
  		return -EINVAL;
  
  	if ((quirks & MT_QUIRK_CONTACT_CNT_ACCURATE) &&
  	    app->num_received >= app->num_expected)
  		return -EAGAIN;
  
  	if (!(quirks & MT_QUIRK_ALWAYS_VALID)) {
  		if (quirks & MT_QUIRK_VALID_IS_INRANGE)
  			valid = *slot->inrange_state;
  		if (quirks & MT_QUIRK_NOT_SEEN_MEANS_UP)
  			valid = *slot->tip_state;
  		if (quirks & MT_QUIRK_VALID_IS_CONFIDENCE)
  			valid = *slot->confidence_state;
  
  		if (!valid)
  			return 0;
  	}
  
  	slotnum = mt_compute_slot(td, app, slot, input);
  	if (slotnum < 0 || slotnum >= td->maxcontacts)
  		return 0;
  
  	if ((quirks & MT_QUIRK_IGNORE_DUPLICATES) && mt) {
  		struct input_mt_slot *i_slot = &mt->slots[slotnum];
  
  		if (input_mt_is_active(i_slot) &&
  		    input_mt_is_used(mt, i_slot))
  			return -EAGAIN;
  	}
  
  	if (quirks & MT_QUIRK_CONFIDENCE)
  		confidence_state = *slot->confidence_state;
  
  	if (quirks & MT_QUIRK_HOVERING)
  		inrange_state = *slot->inrange_state;

  	active = *slot->tip_state || inrange_state;

  	if (app->application == HID_GD_SYSTEM_MULTIAXIS)
  		tool = MT_TOOL_DIAL;

  	else if (unlikely(!confidence_state)) {

  		tool = MT_TOOL_PALM;

  		if (!active && mt &&

  		    input_mt_is_active(&mt->slots[slotnum])) {
  			/*
  			 * The non-confidence was reported for
  			 * previously valid contact that is also no
  			 * longer valid. We can't simply report
  			 * lift-off as userspace will not be aware
  			 * of non-confidence, so we need to split
  			 * it into 2 events: active MT_TOOL_PALM
  			 * and a separate liftoff.
  			 */
  			active = true;
  			set_bit(slotnum, app->pending_palm_slots);
  		}
  	}

  	input_mt_slot(input, slotnum);

  	input_mt_report_slot_state(input, tool, active);

  	if (active) {
  		/* this finger is in proximity of the sensor */
  		int wide = (*slot->w > *slot->h);
  		int major = max(*slot->w, *slot->h);
  		int minor = min(*slot->w, *slot->h);
  		int orientation = wide;
  		int max_azimuth;
  		int azimuth;
  
  		if (slot->a != DEFAULT_ZERO) {

  			/*
  			 * Azimuth is counter-clockwise and ranges from [0, MAX)
  			 * (a full revolution). Convert it to clockwise ranging
  			 * [-MAX/2, MAX/2].
  			 *
  			 * Note that ABS_MT_ORIENTATION require us to report
  			 * the limit of [-MAX/4, MAX/4], but the value can go
  			 * out of range to [-MAX/2, MAX/2] to report an upside
  			 * down ellipsis.
  			 */

  			azimuth = *slot->a;
  			max_azimuth = input_abs_get_max(input,
  							ABS_MT_ORIENTATION);
  			if (azimuth > max_azimuth * 2)
  				azimuth -= max_azimuth * 4;
  			orientation = -azimuth;
  		}

  		if (quirks & MT_QUIRK_TOUCH_SIZE_SCALING) {

  			/*
  			 * divided by two to match visual scale of touch
  			 * for devices with this quirk
  			 */

  			major = major >> 1;
  			minor = minor >> 1;
  		}

  		input_event(input, EV_ABS, ABS_MT_POSITION_X, *slot->x);
  		input_event(input, EV_ABS, ABS_MT_POSITION_Y, *slot->y);
  		input_event(input, EV_ABS, ABS_MT_TOOL_X, *slot->cx);
  		input_event(input, EV_ABS, ABS_MT_TOOL_Y, *slot->cy);
  		input_event(input, EV_ABS, ABS_MT_DISTANCE, !*slot->tip_state);
  		input_event(input, EV_ABS, ABS_MT_ORIENTATION, orientation);
  		input_event(input, EV_ABS, ABS_MT_PRESSURE, *slot->p);
  		input_event(input, EV_ABS, ABS_MT_TOUCH_MAJOR, major);
  		input_event(input, EV_ABS, ABS_MT_TOUCH_MINOR, minor);
  
  		set_bit(MT_IO_FLAGS_ACTIVE_SLOTS, &td->mt_io_flags);
  	}

  	return 0;
  }
  
  static void mt_process_mt_event(struct hid_device *hid,
  				struct mt_application *app,
  				struct hid_field *field,
  				struct hid_usage *usage,
  				__s32 value,
  				bool first_packet)
  {
  	__s32 quirks = app->quirks;
  	struct input_dev *input = field->hidinput->input;
  
  	if (!usage->type || !(hid->claimed & HID_CLAIMED_INPUT))
  		return;
  
  	if (quirks & MT_QUIRK_WIN8_PTP_BUTTONS) {
  
  		/*
  		 * For Win8 PTP touchpads we should only look at
  		 * non finger/touch events in the first_packet of a
  		 * (possible) multi-packet frame.
  		 */
  		if (!first_packet)

  			return;

  		/*
  		 * For Win8 PTP touchpads we map both the clickpad click
  		 * and any "external" left buttons to BTN_LEFT if a
  		 * device claims to have both we need to report 1 for
  		 * BTN_LEFT if either is pressed, so we or all values
  		 * together and report the result in mt_sync_frame().
  		 */
  		if (usage->type == EV_KEY && usage->code == BTN_LEFT) {
  			app->left_button_state |= value;
  			return;

  		}

  	}

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

  }

  static void mt_touch_report(struct hid_device *hid,
  			    struct mt_report_data *rdata)

  {
  	struct mt_device *td = hid_get_drvdata(hid);

  	struct hid_report *report = rdata->report;
  	struct mt_application *app = rdata->application;

  	struct hid_field *field;

  	struct input_dev *input;
  	struct mt_usages *slot;

  	bool first_packet;

  	unsigned count;

  	int r, n;
  	int scantime = 0;
  	int contact_count = -1;

  	/* sticky fingers release in progress, abort */
  	if (test_and_set_bit(MT_IO_FLAGS_RUNNING, &td->mt_io_flags))
  		return;

  	scantime = *app->scantime;
  	app->timestamp = mt_compute_timestamp(app, scantime);
  	if (app->raw_cc != DEFAULT_ZERO)
  		contact_count = *app->raw_cc;

  	/*
  	 * Includes multi-packet support where subsequent
  	 * packets are sent with zero contactcount.
  	 */

  	if (contact_count >= 0) {

  		/*
  		 * For Win8 PTPs the first packet (td->num_received == 0) may
  		 * have a contactcount of 0 if there only is a button event.
  		 * We double check that this is not a continuation packet
  		 * of a possible multi-packet frame be checking that the
  		 * timestamp has changed.
  		 */

  		if ((app->quirks & MT_QUIRK_WIN8_PTP_BUTTONS) &&

  		    app->num_received == 0 &&
  		    app->prev_scantime != scantime)
  			app->num_expected = contact_count;

  		/* A non 0 contact count always indicates a first packet */

  		else if (contact_count)
  			app->num_expected = contact_count;

  	}

  	app->prev_scantime = scantime;

  	first_packet = app->num_received == 0;

  
  	input = report->field[0]->hidinput->input;
  
  	list_for_each_entry(slot, &app->mt_usages, list) {
  		if (!mt_process_slot(td, input, app, slot))
  			app->num_received++;
  	}

  	for (r = 0; r < report->maxfield; r++) {
  		field = report->field[r];
  		count = field->report_count;
  
  		if (!(HID_MAIN_ITEM_VARIABLE & field->flags))
  			continue;
  
  		for (n = 0; n < count; n++)

  			mt_process_mt_event(hid, app, field,
  					    &field->usage[n], field->value[n],
  					    first_packet);

  	}

  	if (app->num_received >= app->num_expected)

  		mt_sync_frame(td, app, input);

  
  	/*
  	 * Windows 8 specs says 2 things:
  	 * - once a contact has been reported, it has to be reported in each
  	 *   subsequent report
  	 * - the report rate when fingers are present has to be at least
  	 *   the refresh rate of the screen, 60 or 120 Hz
  	 *
  	 * I interprete this that the specification forces a report rate of
  	 * at least 60 Hz for a touchscreen to be certified.
  	 * Which means that if we do not get a report whithin 16 ms, either
  	 * something wrong happens, either the touchscreen forgets to send
  	 * a release. Taking a reasonable margin allows to remove issues
  	 * with USB communication or the load of the machine.
  	 *
  	 * Given that Win 8 devices are forced to send a release, this will
  	 * only affect laggish machines and the ones that have a firmware
  	 * defect.
  	 */

  	if (app->quirks & MT_QUIRK_STICKY_FINGERS) {

  		if (test_bit(MT_IO_FLAGS_PENDING_SLOTS, &td->mt_io_flags))
  			mod_timer(&td->release_timer,
  				  jiffies + msecs_to_jiffies(100));
  		else
  			del_timer(&td->release_timer);
  	}

  
  	clear_bit(MT_IO_FLAGS_RUNNING, &td->mt_io_flags);

  }

  static int mt_touch_input_configured(struct hid_device *hdev,

  				     struct hid_input *hi,
  				     struct mt_application *app)

  {
  	struct mt_device *td = hid_get_drvdata(hdev);
  	struct mt_class *cls = &td->mtclass;
  	struct input_dev *input = hi->input;

  	int ret;

  
  	if (!td->maxcontacts)
  		td->maxcontacts = MT_DEFAULT_MAXCONTACT;

  	mt_post_parse(td, app);

  	if (td->serial_maybe)

  		mt_post_parse_default_settings(td, app);

  
  	if (cls->is_indirect)

  		app->mt_flags |= INPUT_MT_POINTER;

  	if (app->quirks & MT_QUIRK_NOT_SEEN_MEANS_UP)

  		app->mt_flags |= INPUT_MT_DROP_UNUSED;

  	/* check for clickpads */

  	if ((app->mt_flags & INPUT_MT_POINTER) &&
  	    (app->buttons_count == 1))

  		td->is_buttonpad = true;
  
  	if (td->is_buttonpad)

  		__set_bit(INPUT_PROP_BUTTONPAD, input->propbit);

  	app->pending_palm_slots = devm_kcalloc(&hi->input->dev,
  					       BITS_TO_LONGS(td->maxcontacts),
  					       sizeof(long),
  					       GFP_KERNEL);
  	if (!app->pending_palm_slots)
  		return -ENOMEM;

  	ret = input_mt_init_slots(input, td->maxcontacts, app->mt_flags);

  	if (ret)
  		return ret;

  	app->mt_flags = 0;

  	return 0;

  }

  #define mt_map_key_clear(c)	hid_map_usage_clear(hi, usage, bit, \
  						    max, EV_KEY, (c))

  static int mt_input_mapping(struct hid_device *hdev, struct hid_input *hi,
  		struct hid_field *field, struct hid_usage *usage,
  		unsigned long **bit, int *max)
  {

  	struct mt_device *td = hid_get_drvdata(hdev);

  	struct mt_application *application;

  	struct mt_report_data *rdata;
  
  	rdata = mt_find_report_data(td, field->report);
  	if (!rdata) {
  		hid_err(hdev, "failed to allocate data for report
  ");
  		return 0;
  	}

  	application = rdata->application;

  	/*
  	 * If mtclass.export_all_inputs is not set, only map fields from
  	 * TouchScreen or TouchPad collections. We need to ignore fields
  	 * that belong to other collections such as Mouse that might have
  	 * the same GenericDesktop usages.
  	 */
  	if (!td->mtclass.export_all_inputs &&
  	    field->application != HID_DG_TOUCHSCREEN &&

  	    field->application != HID_DG_PEN &&

  	    field->application != HID_DG_TOUCHPAD &&
  	    field->application != HID_GD_KEYBOARD &&

  	    field->application != HID_GD_SYSTEM_CONTROL &&

  	    field->application != HID_CP_CONSUMER_CONTROL &&

  	    field->application != HID_GD_WIRELESS_RADIO_CTLS &&

  	    field->application != HID_GD_SYSTEM_MULTIAXIS &&

  	    !(field->application == HID_VD_ASUS_CUSTOM_MEDIA_KEYS &&

  	      application->quirks & MT_QUIRK_ASUS_CUSTOM_UP))

  		return -1;

  	/*

  	 * Some Asus keyboard+touchpad devices have the hotkeys defined in the
  	 * touchpad report descriptor. We need to treat these as an array to
  	 * map usages to input keys.
  	 */

  	if (field->application == HID_VD_ASUS_CUSTOM_MEDIA_KEYS &&

  	    application->quirks & MT_QUIRK_ASUS_CUSTOM_UP &&

  	    (usage->hid & HID_USAGE_PAGE) == HID_UP_CUSTOM) {
  		set_bit(EV_REP, hi->input->evbit);
  		if (field->flags & HID_MAIN_ITEM_VARIABLE)
  			field->flags &= ~HID_MAIN_ITEM_VARIABLE;
  		switch (usage->hid & HID_USAGE) {
  		case 0x10: mt_map_key_clear(KEY_BRIGHTNESSDOWN);	break;
  		case 0x20: mt_map_key_clear(KEY_BRIGHTNESSUP);		break;
  		case 0x35: mt_map_key_clear(KEY_DISPLAY_OFF);		break;
  		case 0x6b: mt_map_key_clear(KEY_F21);			break;
  		case 0x6c: mt_map_key_clear(KEY_SLEEP);			break;
  		default:
  			return -1;
  		}
  		return 1;
  	}

  	if (rdata->is_mt_collection)

  		return mt_touch_input_mapping(hdev, hi, field, usage, bit, max,
  					      application);

  	/*
  	 * some egalax touchscreens have "application == DG_TOUCHSCREEN"
  	 * for the stylus. Overwrite the hid_input application
  	 */
  	if (field->physical == HID_DG_STYLUS)
  		hi->application = HID_DG_STYLUS;

  	/* let hid-core decide for the others */
  	return 0;

  }
  
  static int mt_input_mapped(struct hid_device *hdev, struct hid_input *hi,
  		struct hid_field *field, struct hid_usage *usage,
  		unsigned long **bit, int *max)
  {

  	struct mt_device *td = hid_get_drvdata(hdev);
  	struct mt_report_data *rdata;

  	rdata = mt_find_report_data(td, field->report);
  	if (rdata && rdata->is_mt_collection) {

  		/* We own these mappings, tell hid-input to ignore them */
  		return -1;
  	}

  
  	/* let hid-core decide for the others */
  	return 0;

  }
  
  static int mt_event(struct hid_device *hid, struct hid_field *field,
  				struct hid_usage *usage, __s32 value)
  {
  	struct mt_device *td = hid_get_drvdata(hid);

  	struct mt_report_data *rdata;

  	rdata = mt_find_report_data(td, field->report);
  	if (rdata && rdata->is_mt_collection)

  		return mt_touch_event(hid, field, usage, value);

  	return 0;

  }
  
  static void mt_report(struct hid_device *hid, struct hid_report *report)
  {
  	struct mt_device *td = hid_get_drvdata(hid);

  	struct hid_field *field = report->field[0];

  	struct mt_report_data *rdata;

  
  	if (!(hid->claimed & HID_CLAIMED_INPUT))
  		return;

  	rdata = mt_find_report_data(td, report);
  	if (rdata && rdata->is_mt_collection)
  		return mt_touch_report(hid, rdata);

  	if (field && field->hidinput && field->hidinput->input)
  		input_sync(field->hidinput->input);

  }

  static bool mt_need_to_apply_feature(struct hid_device *hdev,
  				     struct hid_field *field,

  				     struct hid_usage *usage,
  				     enum latency_mode latency,
  				     bool surface_switch,

  				     bool button_switch,
  				     bool *inputmode_found)

  {
  	struct mt_device *td = hid_get_drvdata(hdev);

  	struct mt_class *cls = &td->mtclass;

  	struct hid_report *report = field->report;
  	unsigned int index = usage->usage_index;

  	char *buf;

  	u32 report_len;

  	int max;

  	switch (usage->hid) {
  	case HID_DG_INPUTMODE:

  		/*
  		 * Some elan panels wrongly declare 2 input mode features,
  		 * and silently ignore when we set the value in the second
  		 * field. Skip the second feature and hope for the best.
  		 */
  		if (*inputmode_found)
  			return false;

  		if (cls->quirks & MT_QUIRK_FORCE_GET_FEATURE) {

  			report_len = hid_report_len(report);
  			buf = hid_alloc_report_buf(report, GFP_KERNEL);

  			if (!buf) {

  				hid_err(hdev,
  					"failed to allocate buffer for report
  ");
  				return false;

  			}

  			hid_hw_raw_request(hdev, report->id, buf, report_len,

  					   HID_FEATURE_REPORT,
  					   HID_REQ_GET_REPORT);
  			kfree(buf);
  		}

  		field->value[index] = td->inputmode_value;

  		*inputmode_found = true;

  		return true;

  	case HID_DG_CONTACTMAX:

  		if (cls->maxcontacts) {

  			max = min_t(int, field->logical_maximum,

  				    cls->maxcontacts);

  			if (field->value[index] != max) {
  				field->value[index] = max;
  				return true;
  			}
  		}
  		break;

  
  	case HID_DG_LATENCYMODE:
  		field->value[index] = latency;

  		return true;

  
  	case HID_DG_SURFACESWITCH:
  		field->value[index] = surface_switch;

  		return true;

  
  	case HID_DG_BUTTONSWITCH:
  		field->value[index] = button_switch;

  		return true;

  	}

  	return false; /* no need to update the report */
  }

  static void mt_set_modes(struct hid_device *hdev, enum latency_mode latency,
  			 bool surface_switch, bool button_switch)

  {
  	struct hid_report_enum *rep_enum;
  	struct hid_report *rep;
  	struct hid_usage *usage;
  	int i, j;
  	bool update_report;

  	bool inputmode_found = false;

  
  	rep_enum = &hdev->report_enum[HID_FEATURE_REPORT];
  	list_for_each_entry(rep, &rep_enum->report_list, list) {
  		update_report = false;
  
  		for (i = 0; i < rep->maxfield; i++) {
  			/* Ignore if report count is out of bounds. */
  			if (rep->field[i]->report_count < 1)
  				continue;
  
  			for (j = 0; j < rep->field[i]->maxusage; j++) {
  				usage = &rep->field[i]->usage[j];
  
  				if (mt_need_to_apply_feature(hdev,
  							     rep->field[i],

  							     usage,
  							     latency,
  							     surface_switch,

  							     button_switch,
  							     &inputmode_found))

  					update_report = true;
  			}

  		}

  
  		if (update_report)
  			hid_hw_request(hdev, rep, HID_REQ_SET_REPORT);

  	}
  }

  static void mt_post_parse_default_settings(struct mt_device *td,
  					   struct mt_application *app)

  {

  	__s32 quirks = app->quirks;

  
  	/* unknown serial device needs special quirks */

  	if (list_is_singular(&app->mt_usages)) {

  		quirks |= MT_QUIRK_ALWAYS_VALID;
  		quirks &= ~MT_QUIRK_NOT_SEEN_MEANS_UP;
  		quirks &= ~MT_QUIRK_VALID_IS_INRANGE;
  		quirks &= ~MT_QUIRK_VALID_IS_CONFIDENCE;

  		quirks &= ~MT_QUIRK_CONTACT_CNT_ACCURATE;

  	}

  	app->quirks = quirks;

  }

  static void mt_post_parse(struct mt_device *td, struct mt_application *app)

  {

  	if (!app->have_contact_count)

  		app->quirks &= ~MT_QUIRK_CONTACT_CNT_ACCURATE;

  }

  static int mt_input_configured(struct hid_device *hdev, struct hid_input *hi)

  {
  	struct mt_device *td = hid_get_drvdata(hdev);

  	char *name;
  	const char *suffix = NULL;

  	struct mt_report_data *rdata;

  	struct mt_application *mt_application = NULL;

  	struct hid_report *report;

  	int ret;

  	list_for_each_entry(report, &hi->reports, hidinput_list) {

  		rdata = mt_find_report_data(td, report);
  		if (!rdata) {
  			hid_err(hdev, "failed to allocate data for report
  ");
  			return -ENOMEM;
  		}
  
  		mt_application = rdata->application;

  		if (rdata->is_mt_collection) {

  			ret = mt_touch_input_configured(hdev, hi,
  							mt_application);

  			if (ret)
  				return ret;
  		}

  	}

  	switch (hi->application) {
  	case HID_GD_KEYBOARD:
  	case HID_GD_KEYPAD:
  	case HID_GD_MOUSE:
  	case HID_DG_TOUCHPAD:
  	case HID_GD_SYSTEM_CONTROL:
  	case HID_CP_CONSUMER_CONTROL:
  	case HID_GD_WIRELESS_RADIO_CTLS:
  	case HID_GD_SYSTEM_MULTIAXIS:
  		/* already handled by hid core */
  		break;
  	case HID_DG_TOUCHSCREEN:
  		/* we do not set suffix = "Touchscreen" */
  		hi->input->name = hdev->name;
  		break;
  	case HID_DG_STYLUS:
  		/* force BTN_STYLUS to allow tablet matching in udev */
  		__set_bit(BTN_STYLUS, hi->input->keybit);
  		break;
  	case HID_VD_ASUS_CUSTOM_MEDIA_KEYS:
  		suffix = "Custom Media Keys";
  		break;

  	case HID_DG_PEN:
  		suffix = "Stylus";
  		break;

  	default:
  		suffix = "UNKNOWN";
  		break;

  	}
  
  	if (suffix) {
  		name = devm_kzalloc(&hi->input->dev,
  				    strlen(hdev->name) + strlen(suffix) + 2,
  				    GFP_KERNEL);
  		if (name) {
  			sprintf(name, "%s %s", hdev->name, suffix);
  			hi->input->name = name;
  		}
  	}

  
  	return 0;

  }

  static void mt_fix_const_field(struct hid_field *field, unsigned int usage)
  {
  	if (field->usage[0].hid != usage ||
  	    !(field->flags & HID_MAIN_ITEM_CONSTANT))
  		return;
  
  	field->flags &= ~HID_MAIN_ITEM_CONSTANT;
  	field->flags |= HID_MAIN_ITEM_VARIABLE;
  }
  
  static void mt_fix_const_fields(struct hid_device *hdev, unsigned int usage)
  {
  	struct hid_report *report;
  	int i;
  
  	list_for_each_entry(report,
  			    &hdev->report_enum[HID_INPUT_REPORT].report_list,
  			    list) {
  
  		if (!report->maxfield)
  			continue;
  
  		for (i = 0; i < report->maxfield; i++)
  			if (report->field[i]->maxusage >= 1)
  				mt_fix_const_field(report->field[i], usage);
  	}
  }

  static void mt_release_contacts(struct hid_device *hid)
  {
  	struct hid_input *hidinput;

  	struct mt_application *application;

  	struct mt_device *td = hid_get_drvdata(hid);
  
  	list_for_each_entry(hidinput, &hid->inputs, list) {
  		struct input_dev *input_dev = hidinput->input;
  		struct input_mt *mt = input_dev->mt;
  		int i;
  
  		if (mt) {
  			for (i = 0; i < mt->num_slots; i++) {
  				input_mt_slot(input_dev, i);

  				input_mt_report_slot_inactive(input_dev);

  			}
  			input_mt_sync_frame(input_dev);
  			input_sync(input_dev);
  		}
  	}

  	list_for_each_entry(application, &td->applications, list) {
  		application->num_received = 0;
  	}

  }

  static void mt_expired_timeout(struct timer_list *t)

  {

  	struct mt_device *td = from_timer(td, t, release_timer);
  	struct hid_device *hdev = td->hdev;

  
  	/*
  	 * An input report came in just before we release the sticky fingers,
  	 * it will take care of the sticky fingers.
  	 */
  	if (test_and_set_bit(MT_IO_FLAGS_RUNNING, &td->mt_io_flags))
  		return;

  	if (test_bit(MT_IO_FLAGS_PENDING_SLOTS, &td->mt_io_flags))
  		mt_release_contacts(hdev);

  	clear_bit(MT_IO_FLAGS_RUNNING, &td->mt_io_flags);
  }

  static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
  {

  	int ret, i;

  	struct mt_device *td;

  	const struct mt_class *mtclass = mt_classes; /* MT_CLS_DEFAULT */

  	for (i = 0; mt_classes[i].name ; i++) {
  		if (id->driver_data == mt_classes[i].name) {
  			mtclass = &(mt_classes[i]);
  			break;

  		}
  	}

  	td = devm_kzalloc(&hdev->dev, sizeof(struct mt_device), GFP_KERNEL);

  	if (!td) {
  		dev_err(&hdev->dev, "cannot allocate multitouch data
  ");
  		return -ENOMEM;
  	}

  	td->hdev = hdev;

  	td->mtclass = *mtclass;

  	td->inputmode_value = MT_INPUTMODE_TOUCHSCREEN;

  	hid_set_drvdata(hdev, td);

  	INIT_LIST_HEAD(&td->applications);

  	INIT_LIST_HEAD(&td->reports);

  	if (id->vendor == HID_ANY_ID && id->product == HID_ANY_ID)
  		td->serial_maybe = true;

  	/* This allows the driver to correctly support devices
  	 * that emit events over several HID messages.
  	 */
  	hdev->quirks |= HID_QUIRK_NO_INPUT_SYNC;
  
  	/*
  	 * This allows the driver to handle different input sensors

  	 * that emits events through different applications on the same HID

  	 * device.
  	 */

  	hdev->quirks |= HID_QUIRK_INPUT_PER_APP;

  	if (id->group != HID_GROUP_MULTITOUCH_WIN_8)
  		hdev->quirks |= HID_QUIRK_MULTI_INPUT;

  	if (mtclass->quirks & MT_QUIRK_FORCE_MULTI_INPUT) {
  		hdev->quirks &= ~HID_QUIRK_INPUT_PER_APP;
  		hdev->quirks |= HID_QUIRK_MULTI_INPUT;
  	}

  	timer_setup(&td->release_timer, mt_expired_timeout, 0);

  	ret = hid_parse(hdev);
  	if (ret != 0)

  		return ret;

  	if (mtclass->quirks & MT_QUIRK_FIX_CONST_CONTACT_ID)
  		mt_fix_const_fields(hdev, HID_DG_CONTACTID);

  	ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);

  	if (ret)

  		return ret;

  	ret = sysfs_create_group(&hdev->dev.kobj, &mt_attribute_group);

  	if (ret)
  		dev_warn(&hdev->dev, "Cannot allocate sysfs group for %s
  ",
  				hdev->name);

  	mt_set_modes(hdev, HID_LATENCY_NORMAL, true, true);

  
  	return 0;

  }
  
  #ifdef CONFIG_PM
  static int mt_reset_resume(struct hid_device *hdev)
  {

  	mt_release_contacts(hdev);

  	mt_set_modes(hdev, HID_LATENCY_NORMAL, true, true);

  	return 0;
  }

  
  static int mt_resume(struct hid_device *hdev)
  {

  	/* Some Elan legacy devices require SET_IDLE to be set on resume.
  	 * It should be safe to send it to other devices too.
  	 * Tested on 3M, Stantum, Cypress, Zytronic, eGalax, and Elan panels. */

  	hid_hw_idle(hdev, 0, 0, HID_REQ_SET_IDLE);

  
  	return 0;
  }

  #endif
  
  static void mt_remove(struct hid_device *hdev)
  {

  	struct mt_device *td = hid_get_drvdata(hdev);

  	del_timer_sync(&td->release_timer);

  	sysfs_remove_group(&hdev->dev.kobj, &mt_attribute_group);

  	hid_hw_stop(hdev);

  }