/*
 *  HID driver for eGalax dual-touch panels
 *
 *  Copyright (c) 2010 Stephane Chatty <chatty@enac.fr>
 *
 */

/*
 * 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/usb.h>
#include <linux/slab.h>

MODULE_AUTHOR("Stephane Chatty <chatty@enac.fr>");
MODULE_DESCRIPTION("eGalax dual-touch panel");
MODULE_LICENSE("GPL");

#include "hid-ids.h"

void usbhid_submit_report
(struct hid_device *hid, struct hid_report *report, unsigned char dir);

#define MAX_SLOTS		2
#define MAX_TRKID		USHRT_MAX
#define MAX_EVENTS		360

/* estimated signal-to-noise ratios */
#define SN_MOVE			1024
#define SN_PRESSURE		32

struct egalax_contact {
	int id;
	int x, y, z;
};

struct egalax_data {
	struct egalax_contact contact[MAX_SLOTS];
	int down, valid;
	int x, y, z;
	int slot, prev_slot;
	int mask;
	int trkid;
	int reported;
};

static int egalax_input_mapping(struct hid_device *hdev, struct hid_input *hi,
		struct hid_field *field, struct hid_usage *usage,
		unsigned long **bit, int *max)
{
	int f1 = field->logical_minimum;
	int f2 = field->logical_maximum;
	int df = f2 - f1;

	switch (usage->hid & HID_USAGE_PAGE) {

	case HID_UP_GENDESK:
		switch (usage->hid) {
		case HID_GD_X:
			f1 = 0;
			f2 = 32768;
			df = f2 - f1;
			hid_map_usage(hi, usage, bit, max,
					EV_ABS, ABS_MT_POSITION_X);
			input_set_abs_params(hi->input, ABS_MT_POSITION_X,
					     f1, f2, df / SN_MOVE, 0);
			input_set_abs_params(hi->input, ABS_X,
					     f1, f2, df / SN_MOVE, 0);
			return 1;
		case HID_GD_Y:
			f1 = 0;
			f2 = 32768;
			df = f2 - f1;
			hid_map_usage(hi, usage, bit, max,
					EV_ABS, ABS_MT_POSITION_Y);
			input_set_abs_params(hi->input, ABS_MT_POSITION_Y,
					     f1, f2, df / SN_MOVE, 0);
			input_set_abs_params(hi->input, ABS_Y,
					     f1, f2, df / SN_MOVE, 0);
			return 1;
		}
		return 0;

	case HID_UP_DIGITIZER:
		switch (usage->hid) {
		case HID_DG_TIPSWITCH:
			/* touchscreen emulation */
			hid_map_usage(hi, usage, bit, max, EV_KEY, BTN_TOUCH);
			input_set_capability(hi->input, EV_KEY, BTN_TOUCH);
			return 1;
		case HID_DG_INRANGE:
		case HID_DG_CONFIDENCE:
		case HID_DG_CONTACTCOUNT:
		case HID_DG_CONTACTMAX:
			return -1;
		case HID_DG_CONTACTID:
			field->logical_maximum = MAX_TRKID;
			hid_map_usage(hi, usage, bit, max,
					EV_ABS, ABS_MT_TRACKING_ID);
			input_set_abs_params(hi->input, ABS_MT_TRACKING_ID,
					     0, MAX_TRKID, 0, 0);
			if (!hi->input->mt)
				input_mt_create_slots(hi->input, MAX_SLOTS);
			input_set_events_per_packet(hi->input, MAX_EVENTS);
			return 1;
		case HID_DG_TIPPRESSURE:
			hid_map_usage(hi, usage, bit, max,
				      EV_ABS, ABS_PRESSURE);
			input_set_abs_params(hi->input, ABS_MT_PRESSURE,
					     f1, f2, df / SN_PRESSURE, 0);
			input_set_abs_params(hi->input, ABS_PRESSURE,
					     f1, f2, df / SN_PRESSURE, 0);
			return 1;
		}
		return 0;
	}

	/* ignore others (from other reports we won't get anyway) */
	return -1;
}

static int egalax_input_mapped(struct hid_device *hdev, struct hid_input *hi,
		struct hid_field *field, struct hid_usage *usage,
		unsigned long **bit, int *max)
{
	/* tell hid-input to skip setup of these event types */
	if (usage->type == EV_KEY || usage->type == EV_ABS)
		set_bit(usage->type, hi->input->evbit);
	return -1;
}

static void report_contact(struct egalax_data *td, struct input_dev *input)
{
	struct egalax_contact *f = &td->contact[td->slot];
	struct egalax_contact *oldest = 0;
	int i;

	if (!td->down)
		f->id = -1;
	else if (f->id < 0)
		f->id = td->trkid++ & MAX_TRKID;
	f->x = td->x;
	f->y = td->y;
	f->z = td->z;

	if (td->prev_slot != td->slot) {
		td->prev_slot = td->slot;
		if (td->reported) {
			td->reported = 0;
			return;
		}
	}
	td->reported = 1;

	for (i = 0; i < MAX_SLOTS; i++) {
		f = &td->contact[i];
		input_mt_slot(input, i);
		input_event(input, EV_ABS, ABS_MT_TRACKING_ID, f->id);
		if (f->id < 0)
			continue;
		input_event(input, EV_ABS, ABS_MT_POSITION_X, f->x);
		input_event(input, EV_ABS, ABS_MT_POSITION_Y, f->y);
		input_event(input, EV_ABS, ABS_MT_PRESSURE, f->z);
		if (!oldest)
			oldest = f;
	}

	if (oldest) {
		input_event(input, EV_KEY, BTN_TOUCH, 1);
		input_event(input, EV_ABS, ABS_X, oldest->x);
		input_event(input, EV_ABS, ABS_Y, oldest->y);
		input_event(input, EV_ABS, ABS_PRESSURE, oldest->z);
	} else {
		input_event(input, EV_KEY, BTN_TOUCH, 0);
	}

	input_sync(input);
}

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

	/* Note, eGalax has two product lines: the first is resistive and
	 * uses a standard parallel multitouch protocol (product ID ==
	 * 48xx).  The second is capacitive and uses an unusual "serial"
	 * protocol with a different message for each multitouch finger
	 * (product ID == 72xx).  We do not yet generate a correct event
	 * sequence for the capacitive/serial protocol.
	 */
	if (hid->claimed & HID_CLAIMED_INPUT) {
		struct input_dev *input = field->hidinput->input;

		//printk(KERN_INFO "CHECK: %08x %d", usage->hid, value);
		//return 1;

		switch (usage->hid) {
		case HID_DG_CONFIDENCE:
		case HID_DG_CONTACTCOUNT:
			break;

 		case HID_DG_TIPSWITCH:
			td->down = value;
			td->mask |= 0x01;
			break;
		case HID_DG_INRANGE:
			td->valid = value;
			td->mask |= 0x02;
			break;
		case HID_DG_CONTACTID:
			td->slot = clamp_val(value, 0, MAX_SLOTS - 1);
			td->mask |= 0x04;
			break;
		case HID_GD_X:
			td->x = value;
			td->mask |= 0x08;
			break;
		case HID_GD_Y:
			td->y = value;
			td->mask |= 0x10;
			break;
		case HID_DG_TIPPRESSURE:
			td->z = value;
			td->mask |= 0x20;
			break;

		default:
			/* fallback to the generic hidinput handling */
			return 0;
		}

 		if (td->mask == 0x3f) {
			td->mask = 0;
			if (td->valid)
				report_contact(td, input);
		}
	}

	/* we have handled the hidinput part, 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 egalax_probe(struct hid_device *hdev, const struct hid_device_id *id)
{
	int ret;
	struct egalax_data *td;
	struct hid_report *report;
	int i;

	hdev->quirks |= HID_QUIRK_NO_INPUT_SYNC;

	td = kzalloc(sizeof(struct egalax_data), GFP_KERNEL);
	if (!td) {
		dev_err(&hdev->dev, "cannot allocate eGalax data\n");
		return -ENOMEM;
	}
	for (i = 0; i < MAX_SLOTS; i++)
		td->contact[i].id = -1;
	hid_set_drvdata(hdev, td);

	ret = hid_parse(hdev);
	if (ret)
		goto end;

	ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
	if (ret)
		goto end;

	report = hdev->report_enum[HID_FEATURE_REPORT].report_id_hash[5]; 
	if (report) {
		report->field[0]->value[0] = 2;
		usbhid_submit_report(hdev, report, USB_DIR_OUT);
	}

end:
	if (ret)
		kfree(td);

	return ret;
}

static void egalax_remove(struct hid_device *hdev)
{
	hid_hw_stop(hdev);
	kfree(hid_get_drvdata(hdev));
	hid_set_drvdata(hdev, NULL);
}

static const struct hid_device_id egalax_devices[] = {
	{ HID_USB_DEVICE(USB_VENDOR_ID_DWAV,
			USB_DEVICE_ID_DWAV_EGALAX_MULTITOUCH) },
	{ HID_USB_DEVICE(USB_VENDOR_ID_DWAV,
			USB_DEVICE_ID_DWAV_EGALAX_MULTITOUCH1) },
	{ }
};
MODULE_DEVICE_TABLE(hid, egalax_devices);

static const struct hid_usage_id egalax_grabbed_usages[] = {
	{ HID_ANY_ID, HID_ANY_ID, HID_ANY_ID },
	{ HID_ANY_ID - 1, HID_ANY_ID - 1, HID_ANY_ID - 1}
};

static struct hid_driver egalax_driver = {
	.name = "egalax-touch",
	.id_table = egalax_devices,
	.probe = egalax_probe,
	.remove = egalax_remove,
	.input_mapping = egalax_input_mapping,
	.input_mapped = egalax_input_mapped,
	.usage_table = egalax_grabbed_usages,
	.event = egalax_event,
};

static int __init egalax_init(void)
{
	return hid_register_driver(&egalax_driver);
}

static void __exit egalax_exit(void)
{
	hid_unregister_driver(&egalax_driver);
}

module_init(egalax_init);
module_exit(egalax_exit);