/*
 * ICS MK712 touchscreen controller driver
 *
 * Copyright (c) 1999-2002 Transmeta Corporation
 * Copyright (c) 2005 Rick Koch <n1gp@hotmail.com>
 * Copyright (c) 2005 Vojtech Pavlik <vojtech@suse.cz>
 */

/*
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published by
 * the Free Software Foundation.
 */

/*
 * This driver supports the ICS MicroClock MK712 TouchScreen controller,
 * found in Gateway AOL Connected Touchpad computers.
 *
 * Documentation for ICS MK712 can be found at:
 * 	http://www.icst.com/pdf/mk712.pdf
 */

/*
 * 1999-12-18: original version, Daniel Quinlan
 * 1999-12-19: added anti-jitter code, report pen-up events, fixed mk712_poll
 *             to use queue_empty, Nathan Laredo
 * 1999-12-20: improved random point rejection, Nathan Laredo
 * 2000-01-05: checked in new anti-jitter code, changed mouse protocol, fixed
 *             queue code, added module options, other fixes, Daniel Quinlan
 * 2002-03-15: Clean up for kernel merge <alan@redhat.com>
 *             Fixed multi open race, fixed memory checks, fixed resource
 *             allocation, fixed close/powerdown bug, switched to new init
 * 2005-01-18: Ported to 2.6 from 2.4.28, Rick Koch
 * 2005-02-05: Rewritten for the input layer, Vojtech Pavlik
 *
 */

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/delay.h>
#include <linux/ioport.h>
#include <linux/interrupt.h>
#include <linux/input.h>
#include <asm/io.h>

MODULE_AUTHOR("Daniel Quinlan <quinlan@pathname.com>, Vojtech Pavlik <vojtech@suse.cz>");
MODULE_DESCRIPTION("ICS MicroClock MK712 TouchScreen driver");
MODULE_LICENSE("GPL");

static unsigned int mk712_io = 0x260;	/* Also 0x200, 0x208, 0x300 */
module_param_named(io, mk712_io, uint, 0);
MODULE_PARM_DESC(io, "I/O base address of MK712 touchscreen controller");

static unsigned int mk712_irq = 10;	/* Also 12, 14, 15 */
module_param_named(irq, mk712_irq, uint, 0);
MODULE_PARM_DESC(irq, "IRQ of MK712 touchscreen controller");

/* eight 8-bit registers */
#define MK712_STATUS		0
#define MK712_X			2
#define MK712_Y			4
#define MK712_CONTROL		6
#define MK712_RATE		7

/* status */
#define	MK712_STATUS_TOUCH			0x10
#define	MK712_CONVERSION_COMPLETE		0x80

/* control */
#define MK712_ENABLE_INT			0x01
#define MK712_INT_ON_CONVERSION_COMPLETE	0x02
#define MK712_INT_ON_CHANGE_IN_TOUCH_STATUS	0x04
#define MK712_ENABLE_PERIODIC_CONVERSIONS	0x10
#define MK712_READ_ONE_POINT			0x20
#define MK712_POWERUP				0x40

static int mk712_used = 0;
static struct input_dev mk712_dev;
static DEFINE_SPINLOCK(mk712_lock);

static irqreturn_t mk712_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
	unsigned char status;
	static int debounce = 1;
	static unsigned short last_x;
	static unsigned short last_y;

	spin_lock(&mk712_lock);
	input_regs(&mk712_dev, regs);

	status = inb(mk712_io + MK712_STATUS);

	if (~status & MK712_CONVERSION_COMPLETE) {
		debounce = 1;
		goto end;
	}

	if (~status & MK712_STATUS_TOUCH)
	{
		debounce = 1;
		input_report_key(&mk712_dev, BTN_TOUCH, 0);
		goto end;
	}

	if (debounce)
	{
		debounce = 0;
		goto end;
	}

	input_report_key(&mk712_dev, BTN_TOUCH, 1);
	input_report_abs(&mk712_dev, ABS_X, last_x);
	input_report_abs(&mk712_dev, ABS_Y, last_y);

end:

	last_x = inw(mk712_io + MK712_X) & 0x0fff;
	last_y = inw(mk712_io + MK712_Y) & 0x0fff;
	input_sync(&mk712_dev);
	spin_unlock(&mk712_lock);
	return IRQ_HANDLED;
}

static int mk712_open(struct input_dev *dev)
{
	unsigned long flags;

	spin_lock_irqsave(&mk712_lock, flags);

	if (!mk712_used++) {

		outb(0, mk712_io + MK712_CONTROL); /* Reset */

		outb(MK712_ENABLE_INT | MK712_INT_ON_CONVERSION_COMPLETE |
			MK712_INT_ON_CHANGE_IN_TOUCH_STATUS |
			MK712_ENABLE_PERIODIC_CONVERSIONS |
			MK712_POWERUP, mk712_io + MK712_CONTROL);

		outb(10, mk712_io + MK712_RATE); /* 187 points per second */
	}

	spin_unlock_irqrestore(&mk712_lock, flags);

	return 0;
}

static void mk712_close(struct input_dev *dev)
{
	unsigned long flags;

	spin_lock_irqsave(&mk712_lock, flags);

	if (!--mk712_used)
		outb(0, mk712_io + MK712_CONTROL);

	spin_unlock_irqrestore(&mk712_lock, flags);
}

static struct input_dev mk712_dev = {
	.evbit   = { BIT(EV_KEY) | BIT(EV_ABS) },
	.keybit  = { [LONG(BTN_TOUCH)] = BIT(BTN_TOUCH) },
	.absbit  = { BIT(ABS_X) | BIT(ABS_Y) },
	.open    = mk712_open,
	.close   = mk712_close,
	.name    = "ICS MicroClock MK712 TouchScreen",
	.phys    = "isa0260/input0",
	.absmin  = { [ABS_X] = 0, [ABS_Y] = 0 },
	.absmax  = { [ABS_X] = 0xfff, [ABS_Y] = 0xfff },
	.absfuzz = { [ABS_X] = 88, [ABS_Y] = 88 },
	.id      = {
		.bustype = BUS_ISA,
		.vendor  = 0x0005,
		.product = 0x0001,
		.version = 0x0100,
	},
};

int __init mk712_init(void)
{

	if(!request_region(mk712_io, 8, "mk712"))
	{
		printk(KERN_WARNING "mk712: unable to get IO region\n");
		return -ENODEV;
	}

	outb(0, mk712_io + MK712_CONTROL);

	if ((inw(mk712_io + MK712_X) & 0xf000) ||	/* Sanity check */
	    (inw(mk712_io + MK712_Y) & 0xf000) ||
	    (inw(mk712_io + MK712_STATUS) & 0xf333)) {
		printk(KERN_WARNING "mk712: device not present\n");
		release_region(mk712_io, 8);
		return -ENODEV;
	}

	if(request_irq(mk712_irq, mk712_interrupt, 0, "mk712", &mk712_dev))
	{
		printk(KERN_WARNING "mk712: unable to get IRQ\n");
		release_region(mk712_io, 8);
		return -EBUSY;
	}

	input_register_device(&mk712_dev);

	printk(KERN_INFO "input: ICS MicroClock MK712 TouchScreen at %#x irq %d\n", mk712_io, mk712_irq);

	return 0;
}

static void __exit mk712_exit(void)
{
	input_unregister_device(&mk712_dev);
	free_irq(mk712_irq, &mk712_dev);
	release_region(mk712_io, 8);
}

module_init(mk712_init);
module_exit(mk712_exit);