// SPDX-License-Identifier: GPL-2.0-only
/*
 * 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 driver supports the ICS MicroClock MK712 TouchScreen controller,
 * found in Gateway AOL Connected Touchpad computers.
 *
 * Documentation for ICS MK712 can be found at:
 *      https://www.idt.com/general-parts/mk712-touch-screen-controller
 */

/*
 * 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/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_hw_named(io, mk712_io, uint, ioport, 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_hw_named(irq, mk712_irq, uint, irq, 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 struct input_dev *mk712_dev;
static DEFINE_SPINLOCK(mk712_lock);

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

        spin_lock(&mk712_lock);

        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);

        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);

        outb(0, mk712_io + MK712_CONTROL);

        spin_unlock_irqrestore(&mk712_lock, flags);
}

static int __init mk712_init(void)
{
        int err;

        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");
                err = -ENODEV;
                goto fail1;
        }

        mk712_dev = input_allocate_device();
        if (!mk712_dev) {
                printk(KERN_ERR "mk712: not enough memory\n");
                err = -ENOMEM;
                goto fail1;
        }

        mk712_dev->name = "ICS MicroClock MK712 TouchScreen";
        mk712_dev->phys = "isa0260/input0";
        mk712_dev->id.bustype = BUS_ISA;
        mk712_dev->id.vendor  = 0x0005;
        mk712_dev->id.product = 0x0001;
        mk712_dev->id.version = 0x0100;

        mk712_dev->open    = mk712_open;
        mk712_dev->close   = mk712_close;

        mk712_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
        mk712_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
        input_set_abs_params(mk712_dev, ABS_X, 0, 0xfff, 88, 0);
        input_set_abs_params(mk712_dev, ABS_Y, 0, 0xfff, 88, 0);

        if (request_irq(mk712_irq, mk712_interrupt, 0, "mk712", mk712_dev)) {
                printk(KERN_WARNING "mk712: unable to get IRQ\n");
                err = -EBUSY;
                goto fail1;
        }

        err = input_register_device(mk712_dev);
        if (err)
                goto fail2;

        return 0;

 fail2: free_irq(mk712_irq, mk712_dev);
 fail1: input_free_device(mk712_dev);
        release_region(mk712_io, 8);
        return err;
}

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);