path: root/drivers/hid/hid-multitouch.c

/*
 *  HID driver for multitouch panels
 *
 *  Copyright (c) 2010-2012 Stephane Chatty <chatty@enac.fr>
 *  Copyright (c) 2010-2012 Benjamin Tissoires <benjamin.tissoires@gmail.com>
 *  Copyright (c) 2010-2012 Ecole Nationale de l'Aviation Civile, France
 *
 *  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 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.
 */

#include <linux/device.h>
#include <linux/hid.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/usb.h>
#include <linux/input/mt.h>
#include "usbhid/usbhid.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	(1 << 0)
#define MT_QUIRK_SLOT_IS_CONTACTID	(1 << 1)
#define MT_QUIRK_CYPRESS		(1 << 2)
#define MT_QUIRK_SLOT_IS_CONTACTNUMBER	(1 << 3)
#define MT_QUIRK_ALWAYS_VALID		(1 << 4)
#define MT_QUIRK_VALID_IS_INRANGE	(1 << 5)
#define MT_QUIRK_VALID_IS_CONFIDENCE	(1 << 6)
#define MT_QUIRK_SLOT_IS_CONTACTID_MINUS_ONE	(1 << 8)

struct mt_slot {
	__s32 x, y, p, w, h;
	__s32 contactid;	/* the device ContactID assigned to this slot */
	bool touch_state;	/* is the touch valid? */
	bool seen_in_this_frame;/* has this slot been updated */
};

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 */
};

struct mt_fields {
	unsigned usages[HID_MAX_FIELDS];
	unsigned int length;
};

struct mt_device {
	struct mt_slot curdata;	/* placeholder of incoming data */
	struct mt_class mtclass;	/* our mt device class */
	struct mt_fields *fields;	/* temporary placeholder for storing the
					   multitouch fields */
	unsigned last_field_index;	/* last field index of the report */
	unsigned last_slot_field;	/* the last field of a slot */
	__s8 inputmode;		/* InputMode HID feature, -1 if non-existent */
	__s8 inputmode_index;	/* InputMode HID feature index in the report */
	__s8 maxcontact_report_id;	/* Maximum Contact Number HID feature,
				   -1 if non-existent */
	__u8 num_received;	/* how many contacts we received */
	__u8 num_expected;	/* expected last contact index */
	__u8 maxcontacts;
	__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 */
	bool curvalid;		/* is the current contact valid? */
	struct mt_slot *slots;
};

/* 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
#define MT_CLS_DUAL_NSMU_CONTACTID		0x0008
#define MT_CLS_INRANGE_CONTACTNUMBER		0x0009

/* vendor specific classes */
#define MT_CLS_3M				0x0101
#define MT_CLS_CYPRESS				0x0102
#define MT_CLS_EGALAX				0x0103
#define MT_CLS_EGALAX_SERIAL			0x0104
#define MT_CLS_TOPSEED				0x0105
#define MT_CLS_PANASONIC			0x0106

#define MT_DEFAULT_MAXCONTACT	10

#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_device *td)
{
	if (td->curdata.contactid != 0 || td->num_received == 0)
		return td->curdata.contactid;
	else
		return -1;
}

static int find_slot_from_contactid(struct mt_device *td)
{
	int i;
	for (i = 0; i < td->maxcontacts; ++i) {
		if (td->slots[i].contactid == td->curdata.contactid &&
			td->slots[i].touch_state)
			return i;
	}
	for (i = 0; i < td->maxcontacts; ++i) {
		if (!td->slots[i].seen_in_this_frame &&
			!td->slots[i].touch_state)
			return i;
	}
	/* should not occurs. If this happens that means
	 * that the device sent more touches that it says
	 * in the report descriptor. It is ignored then. */
	return -1;
}

static struct mt_class mt_classes[] = {
	{ .name = MT_CLS_DEFAULT,
		.quirks = MT_QUIRK_NOT_SEEN_MEANS_UP },
	{ .name = MT_CLS_SERIAL,
		.quirks = MT_QUIRK_ALWAYS_VALID},
	{ .name