// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  Copyright (c) 1999-2001 Vojtech Pavlik
 */

/*
 *  82C710 C&T mouse port chip driver for Linux
 */

#include <linux/delay.h>
#include <linux/module.h>
#include <linux/ioport.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/serio.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/platform_device.h>
#include <linux/slab.h>

#include <asm/io.h>

MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
MODULE_DESCRIPTION("82C710 C&T mouse port chip driver");
MODULE_LICENSE("GPL");

/*
 * ct82c710 interface
 */

#define CT82C710_DEV_IDLE     0x01		/* Device Idle */
#define CT82C710_RX_FULL      0x02		/* Device Char received */
#define CT82C710_TX_IDLE      0x04		/* Device XMIT Idle */
#define CT82C710_RESET        0x08		/* Device Reset */
#define CT82C710_INTS_ON      0x10		/* Device Interrupt On */
#define CT82C710_ERROR_FLAG   0x20		/* Device Error */
#define CT82C710_CLEAR        0x40		/* Device Clear */
#define CT82C710_ENABLE       0x80		/* Device Enable */

#define CT82C710_IRQ          12

#define CT82C710_DATA         ct82c710_iores.start
#define CT82C710_STATUS       (ct82c710_iores.start + 1)

static struct serio *ct82c710_port;
static struct platform_device *ct82c710_device;
static struct resource ct82c710_iores;

/*
 * Interrupt handler for the 82C710 mouse port. A character
 * is waiting in the 82C710.
 */

static irqreturn_t ct82c710_interrupt(int cpl, void *dev_id)
{
	return serio_interrupt(ct82c710_port, inb(CT82C710_DATA), 0);
}

/*
 * Wait for device to send output char and flush any input char.
 */

static int ct82c170_wait(void)
{
	int timeout = 60000;

	while ((inb(CT82C710_STATUS) & (CT82C710_RX_FULL | CT82C710_TX_IDLE | CT82C710_DEV_IDLE))
		       != (CT82C710_DEV_IDLE | CT82C710_TX_IDLE) && timeout) {

		if (inb_p(CT82C710_STATUS) & CT82C710_RX_FULL) inb_p(CT82C710_DATA);

		udelay(1);
		timeout--;
	}

	return !timeout;
}

static void ct82c710_close(struct serio *serio)
{
	if (ct82c170_wait())
		printk(KERN_WARNING "ct82c710.c: Device busy in close()\n");

	outb_p(inb_p(CT82C710_STATUS) & ~(CT82C710_ENABLE | CT82C710_INTS_ON), CT82C710_STATUS);

	if (ct82c170_wait())
		printk(KERN_WARNING "ct82c710.c: Device busy in close()\n");

	free_irq(CT82C710_IRQ, NULL);
}

static int ct82c710_open(struct serio *serio)
{
	unsigned char status;
	int err;

	err = request_irq(CT82C710_IRQ, ct82c710_interrupt, 0, "ct82c710", NULL);
	if (err)
		return err;

	status = inb_p(CT82C710_STATUS);

	status |= (CT82C710_ENABLE | CT82C710_RESET);
	outb_p(status, CT82C710_STATUS);

	status &= ~(CT82C710_RESET);
	outb_p(status, CT82C710_STATUS);

	status |= CT82C710_INTS_ON;
	outb_p(status, CT82C710_STATUS);	/* Enable interrupts */

	while (ct82c170_wait()) {
		printk(KERN_ERR "ct82c710: Device busy in open()\n");
		status &= ~(CT82C710_ENABLE | CT82C710_INTS_ON);
		outb_p(status, CT82C710_STATUS);
		free_irq(CT82C710_IRQ, NULL);
		return -EBUSY;
	}

	return 0;
}

/*
 * Write to the 82C710 mouse device.
 */

static int ct82c710_write(struct serio *port, unsigned char c)
{
	if (ct82c170_wait()) return -1;
	outb_p(c, CT82C710_DATA);
	return 0;
}

/*
 * See if we can find a 82C710 device. Read mouse address.
 */

static int __init ct82c710_detect(void)
{
	outb_p(0x55, 0x2fa);				/* Any value except 9, ff or 36 */
	outb_p(0xaa, 0x3fa);				/* Inverse of 55 */
	outb_p(0x36, 0x3fa);				/* Address the chip */
	outb_p(0xe4, 0x3fa);				/* 390/4; 390 = config address */
	outb_p(0x1b, 0x2fa);				/* Inverse of e4 */
	outb_p(0x0f, 0x390);				/* Write index */
	if (inb_p(0x391) != 0xe4)			/* Config address found? */
		return -ENODEV;				/* No: no 82C710 here */

	outb_p(0x0d, 0x390);				/* Write index */
	ct82c710_iores.start = inb_p(0x391) << 2;	/* Get mouse I/O address */
	ct82c710_iores.end = ct82c710_iores.start + 1;
	ct82c710_iores.flags = IORESOURCE_IO;
	outb_p(0x0f, 0x390);
	outb_p(0x0f, 0x391);				/* Close config mode */

	return 0;
}

static int ct82c710_probe(struct platform_device *dev)
{
	ct82c710_port = kzalloc(sizeof(*ct82c710_port), GFP_KERNEL);
	if (!ct82c710_port)
		return -ENOMEM;

	ct82c710_port->id.type = SERIO_8042;
	ct82c710_port->dev.parent = &dev->dev;
	ct82c710_port->open = ct82c710_open;
	ct82c710_port->close = ct82c710_close;
	ct82c710_port->write = ct82c710_write;
	strscpy(ct82c710_port->name, "C&T 82c710 mouse port",
		sizeof(ct82c710_port->name));
	snprintf(ct82c710_port->phys, sizeof(ct82c710_port->phys),
		 "isa%16llx/serio0", (unsigned long long)CT82C710_DATA);

	serio_register_port(ct82c710_port);

	printk(KERN_INFO "serio: C&T 82c710 mouse port at %#llx irq %d\n",
		(unsigned long long)CT82C710_DATA, CT82C710_IRQ);

	return 0;
}

static void ct82c710_remove(struct platform_device *dev)
{
	serio_unregister_port(ct82c710_port);
}

static struct platform_driver ct82c710_driver = {
	.driver		= {
		.name	= "ct82c710",
	},
	.probe		= ct82c710_probe,
	.remove_new	= ct82c710_remove,
};


static int __init ct82c710_init(void)
{
	int error;

	error = ct82c710_detect();
	if (error)
		return error;

	error = platform_driver_register(&ct82c710_driver);
	if (error)
		return error;

	ct82c710_device = platform_device_alloc("ct82c710", -1);
	if (!ct82c710_device) {
		error = -ENOMEM;
		goto err_unregister_driver;
	}

	error = platform_device_add_resources(ct82c710_device, &ct82c710_iores, 1);
	if (error)
		goto err_free_device;

	error = platform_device_add(ct82c710_device);
	if (error)
		goto err_free_device;

	return 0;

 err_free_device:
	platform_device_put(ct82c710_device);
 err_unregister_driver:
	platform_driver_unregister(&ct82c710_driver);
	return error;
}

static void __exit ct82c710_exit(void)
{
	platform_device_unregister(ct82c710_device);
	platform_driver_unregister(&ct82c710_driver);
}

module_init(ct82c710_init);
module_exit(ct82c710_exit);