/*
 *
 *  Copyright (c) 2002 Osamu Tomita
 *
 *  Based on the work of:
 *	James Banks		Matthew Dillon
 *	David Giller		Nathan Laredo
 *	Linus Torvalds		Johan Myreen
 *	Cliff Matthews		Philip Blundell
 *	Russell King		Vojtech Pavlik
 */

/*
 * NEC PC-9801 Bus Mouse Driver for Linux
 */

/*
 * 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.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 * 
 */

#include <linux/config.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/delay.h>
#include <linux/ioport.h>
#include <linux/init.h>
#include <linux/input.h>
#include <linux/interrupt.h>

#include <asm/io.h>
#include <asm/irq.h>

MODULE_AUTHOR("Osamu Tomita <tomita@cinet.co.jp>");
MODULE_DESCRIPTION("PC-9801 busmouse driver");
MODULE_LICENSE("GPL");

#define	PC98BM_BASE		0x7fd9
#define	PC98BM_DATA_PORT	PC98BM_BASE + 0
/*	PC98BM_SIGNATURE_PORT	does not exist */
#define	PC98BM_CONTROL_PORT	PC98BM_BASE + 4
/*	PC98BM_INTERRUPT_PORT	does not exist */
#define	PC98BM_CONFIG_PORT	PC98BM_BASE + 6

#define	PC98BM_ENABLE_IRQ	0x00
#define	PC98BM_DISABLE_IRQ	0x10
#define	PC98BM_READ_X_LOW	0x80
#define	PC98BM_READ_X_HIGH	0xa0
#define	PC98BM_READ_Y_LOW	0xc0
#define	PC98BM_READ_Y_HIGH	0xe0

#define PC98BM_DEFAULT_MODE	0x93
/*	PC98BM_CONFIG_BYTE	is not used */
/*	PC98BM_SIGNATURE_BYTE	is not used */

#define PC98BM_TIMER_PORT	0xbfdb
#define PC98BM_DEFAULT_TIMER_VAL	0x00

#define PC98BM_IRQ		13

static int pc98bm_irq = PC98BM_IRQ;
module_param_named(irq, pc98bm_irq, uint, 0);
MODULE_PARM_DESC(irq, "IRQ number (13=default)");

__obsolete_setup("pc98bm_irq=");

static int pc98bm_used = 0;

static irqreturn_t pc98bm_interrupt(int irq, void *dev_id, struct pt_regs *regs);

static int pc98bm_open(struct input_dev *dev)
{
	if (pc98bm_used++)
		return 0;
	if (request_irq(pc98bm_irq, pc98bm_interrupt, 0, "98busmouse", NULL)) {
		pc98bm_used--;
		printk(KERN_ERR "98busmouse.c: Can't allocate irq %d\n", pc98bm_irq);
		return -EBUSY;
	}
	outb(PC98BM_ENABLE_IRQ, PC98BM_CONTROL_PORT);
	return 0;
}

static void pc98bm_close(struct input_dev *dev)
{
	if (--pc98bm_used)
		return;
	outb(PC98BM_DISABLE_IRQ, PC98BM_CONTROL_PORT);
	free_irq(pc98bm_irq, NULL);
}

static struct input_dev pc98bm_dev = {
	.evbit	= { BIT(EV_KEY) | BIT(EV_REL) },
	.keybit = { [LONG(BTN_LEFT)] = BIT(BTN_LEFT) | BIT(BTN_MIDDLE) | BIT(BTN_RIGHT) },
	.relbit	= { BIT(REL_X) | BIT(REL_Y) },
	.open	= pc98bm_open,
	.close	= pc98bm_close,
	.name	= "PC-9801 bus mouse",
	.phys	= "isa7fd9/input0",
	.id	= {
		.bustype = BUS_ISA,
		.vendor  = 0x0004,
		.product = 0x0001,
		.version = 0x0100,
	},
};

static irqreturn_t pc98bm_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
	char dx, dy;
	unsigned char buttons;

	outb(PC98BM_READ_X_LOW, PC98BM_CONTROL_PORT);
	dx = (inb(PC98BM_DATA_PORT) & 0xf);
	outb(PC98BM_READ_X_HIGH, PC98BM_CONTROL_PORT);
	dx |= (inb(PC98BM_DATA_PORT) & 0xf) << 4;
	outb(PC98BM_READ_Y_LOW, PC98BM_CONTROL_PORT);
	dy = (inb(PC98BM_DATA_PORT) & 0xf);
	outb(PC98BM_READ_Y_HIGH, PC98BM_CONTROL_PORT);
	buttons = inb(PC98BM_DATA_PORT);
	dy |= (buttons & 0xf) << 4;
	buttons = ~buttons >> 5;

	input_report_rel(&pc98bm_dev, REL_X, dx);
	input_report_rel(&pc98bm_dev, REL_Y, dy);
	input_report_key(&pc98bm_dev, BTN_RIGHT,  buttons & 1);
	input_report_key(&pc98bm_dev, BTN_MIDDLE, buttons & 2);
	input_report_key(&pc98bm_dev, BTN_LEFT,   buttons & 4);
	input_sync(&pc98bm_dev);

	outb(PC98BM_ENABLE_IRQ, PC98BM_CONTROL_PORT);

	return IRQ_HANDLED;
}

static int __init pc98bm_init(void)
{
	int i;

	for (i = 0; i <= 6; i += 2) {
		if (!request_region(PC98BM_BASE + i, 1, "98busmouse")) {
			printk(KERN_ERR "98busmouse.c: Can't allocate ports at %#x\n", PC98BM_BASE + i);
			while (i > 0) {
				i -= 2;
				release_region(PC98BM_BASE + i, 1);
			}

			return -EBUSY;
		}

	}

	if (!request_region(PC98BM_TIMER_PORT, 1, "98busmouse")) {
		printk(KERN_ERR "98busmouse.c: Can't allocate ports at %#x\n", PC98BM_TIMER_PORT);
		for (i = 0; i <= 6; i += 2)
			release_region(PC98BM_BASE + i, 1);

		return -EBUSY;
	}

	outb(PC98BM_DEFAULT_MODE, PC98BM_CONFIG_PORT);
	outb(PC98BM_DISABLE_IRQ, PC98BM_CONTROL_PORT);

	outb(PC98BM_DEFAULT_TIMER_VAL, PC98BM_TIMER_PORT);

	input_register_device(&pc98bm_dev);
	
	printk(KERN_INFO "input: PC-9801 bus mouse at %#x irq %d\n", PC98BM_BASE, pc98bm_irq);

	return 0;
}

static void __exit pc98bm_exit(void)
{
	int i;

	input_unregister_device(&pc98bm_dev);
	for (i = 0; i <= 6; i += 2)
		release_region(PC98BM_BASE + i, 1);

	release_region(PC98BM_TIMER_PORT, 1);
}

module_init(pc98bm_init);
module_exit(pc98bm_exit);