// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  Copyright (c) 1999-2001 Vojtech Pavlik
 *
 *  Based on the work of:
 *      James Banks             Matthew Dillon
 *      David Giller            Nathan Laredo
 *      Linus Torvalds          Johan Myreen
 *      Cliff Matthews          Philip Blundell
 *      Russell King
 */

/*
 * Logitech Bus Mouse Driver for Linux
 */

#include <linux/module.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("Vojtech Pavlik <vojtech@ucw.cz>");
MODULE_DESCRIPTION("Logitech busmouse driver");
MODULE_LICENSE("GPL");

#define LOGIBM_BASE             0x23c
#define LOGIBM_EXTENT           4

#define LOGIBM_DATA_PORT        LOGIBM_BASE + 0
#define LOGIBM_SIGNATURE_PORT   LOGIBM_BASE + 1
#define LOGIBM_CONTROL_PORT     LOGIBM_BASE + 2
#define LOGIBM_CONFIG_PORT      LOGIBM_BASE + 3

#define LOGIBM_ENABLE_IRQ       0x00
#define LOGIBM_DISABLE_IRQ      0x10
#define LOGIBM_READ_X_LOW       0x80
#define LOGIBM_READ_X_HIGH      0xa0
#define LOGIBM_READ_Y_LOW       0xc0
#define LOGIBM_READ_Y_HIGH      0xe0

#define LOGIBM_DEFAULT_MODE     0x90
#define LOGIBM_CONFIG_BYTE      0x91
#define LOGIBM_SIGNATURE_BYTE   0xa5

#define LOGIBM_IRQ              5

static int logibm_irq = LOGIBM_IRQ;
module_param_hw_named(irq, logibm_irq, uint, irq, 0);
MODULE_PARM_DESC(irq, "IRQ number (5=default)");

static struct input_dev *logibm_dev;

static irqreturn_t logibm_interrupt(int irq, void *dev_id)
{
        char dx, dy;
        unsigned char buttons;

        outb(LOGIBM_READ_X_LOW, LOGIBM_CONTROL_PORT);
        dx = (inb(LOGIBM_DATA_PORT) & 0xf);
        outb(LOGIBM_READ_X_HIGH, LOGIBM_CONTROL_PORT);
        dx |= (inb(LOGIBM_DATA_PORT) & 0xf) << 4;
        outb(LOGIBM_READ_Y_LOW, LOGIBM_CONTROL_PORT);
        dy = (inb(LOGIBM_DATA_PORT) & 0xf);
        outb(LOGIBM_READ_Y_HIGH, LOGIBM_CONTROL_PORT);
        buttons = inb(LOGIBM_DATA_PORT);
        dy |= (buttons & 0xf) << 4;
        buttons = ~buttons >> 5;

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

        outb(LOGIBM_ENABLE_IRQ, LOGIBM_CONTROL_PORT);
        return IRQ_HANDLED;
}

static int logibm_open(struct input_dev *dev)
{
        if (request_irq(logibm_irq, logibm_interrupt, 0, "logibm", NULL)) {
                printk(KERN_ERR "logibm.c: Can't allocate irq %d\n", logibm_irq);
                return -EBUSY;
        }
        outb(LOGIBM_ENABLE_IRQ, LOGIBM_CONTROL_PORT);
        return 0;
}

static void logibm_close(struct input_dev *dev)
{
        outb(LOGIBM_DISABLE_IRQ, LOGIBM_CONTROL_PORT);
        free_irq(logibm_irq, NULL);
}

static int __init logibm_init(void)
{
        int err;

        if (!request_region(LOGIBM_BASE, LOGIBM_EXTENT, "logibm")) {
                printk(KERN_ERR "logibm.c: Can't allocate ports at %#x\n", LOGIBM_BASE);
                return -EBUSY;
        }

        outb(LOGIBM_CONFIG_BYTE, LOGIBM_CONFIG_PORT);
        outb(LOGIBM_SIGNATURE_BYTE, LOGIBM_SIGNATURE_PORT);
        udelay(100);

        if (inb(LOGIBM_SIGNATURE_PORT) != LOGIBM_SIGNATURE_BYTE) {
                printk(KERN_INFO "logibm.c: Didn't find Logitech busmouse at %#x\n", LOGIBM_BASE);
                err = -ENODEV;
                goto err_release_region;
        }

        outb(LOGIBM_DEFAULT_MODE, LOGIBM_CONFIG_PORT);
        outb(LOGIBM_DISABLE_IRQ, LOGIBM_CONTROL_PORT);

        logibm_dev = input_allocate_device();
        if (!logibm_dev) {
                printk(KERN_ERR "logibm.c: Not enough memory for input device\n");
                err = -ENOMEM;
                goto err_release_region;
        }

        logibm_dev->name = "Logitech bus mouse";
        logibm_dev->phys = "isa023c/input0";
        logibm_dev->id.bustype = BUS_ISA;
        logibm_dev->id.vendor  = 0x0003;
        logibm_dev->id.product = 0x0001;
        logibm_dev->id.version = 0x0100;

        logibm_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_REL);
        logibm_dev->keybit[BIT_WORD(BTN_LEFT)] = BIT_MASK(BTN_LEFT) |
                BIT_MASK(BTN_MIDDLE) | BIT_MASK(BTN_RIGHT);
        logibm_dev->relbit[0] = BIT_MASK(REL_X) | BIT_MASK(REL_Y);

        logibm_dev->open  = logibm_open;
        logibm_dev->close = logibm_close;

        err = input_register_device(logibm_dev);
        if (err)
                goto err_free_dev;

        return 0;

 err_free_dev:
        input_free_device(logibm_dev);
 err_release_region:
        release_region(LOGIBM_BASE, LOGIBM_EXTENT);

        return err;
}

static void __exit logibm_exit(void)
{
        input_unregister_device(logibm_dev);
        release_region(LOGIBM_BASE, LOGIBM_EXTENT);
}

module_init(logibm_init);
module_exit(logibm_exit);