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

/*
 * XT keyboard driver for Linux
 */

#include <linux/slab.h>
#include <linux/module.h>
#include <linux/input.h>
#include <linux/serio.h>

#define DRIVER_DESC	"XT keyboard driver"

MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");

#define XTKBD_EMUL0	0xe0
#define XTKBD_EMUL1	0xe1
#define XTKBD_KEY	0x7f
#define XTKBD_RELEASE	0x80

static unsigned char xtkbd_keycode[256] = {
	  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 15,
	 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31,
	 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47,
	 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63,
	 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79,
	 80, 81, 82, 83,  0,  0,  0, 87, 88,  0,  0,  0,  0,  0,  0,  0,
	  0,  0,  0,  0,  0, 87, 88,  0,  0,  0,  0,110,111,103,108,105,
	106
};

struct xtkbd {
	unsigned char keycode[256];
	struct input_dev *dev;
	struct serio *serio;
	char phys[32];
};

static irqreturn_t xtkbd_interrupt(struct serio *serio,
	unsigned char data, unsigned int flags)
{
	struct xtkbd *xtkbd = serio_get_drvdata(serio);

	switch (data) {
		case XTKBD_EMUL0:
		case XTKBD_EMUL1:
			break;
		default:

			if (xtkbd->keycode[data & XTKBD_KEY]) {
				input_report_key(xtkbd->dev, xtkbd->keycode[data & XTKBD_KEY], !(data & XTKBD_RELEASE));
				input_sync(xtkbd->dev);
			} else {
				printk(KERN_WARNING "xtkbd.c: Unknown key (scancode %#x) %s.\n",
					data & XTKBD_KEY, data & XTKBD_RELEASE ? "released" : "pressed");
			}
	}
	return IRQ_HANDLED;
}

static int xtkbd_connect(struct serio *serio, struct serio_driver *drv)
{
	struct xtkbd *xtkbd;
	struct input_dev *input_dev;
	int err = -ENOMEM;
	int i;

	xtkbd = kmalloc(sizeof(struct xtkbd), GFP_KERNEL);
	input_dev = input_allocate_device();
	if (!xtkbd || !input_dev)
		goto fail1;

	xtkbd->serio = serio;
	xtkbd->dev = input_dev;
	snprintf(xtkbd->phys, sizeof(xtkbd->phys), "%s/input0", serio->phys);
	memcpy(xtkbd->keycode, xtkbd_keycode, sizeof(xtkbd->keycode));

	input_dev->name = "XT Keyboard";
	input_dev->phys = xtkbd->phys;
	input_dev->id.bustype = BUS_XTKBD;
	input_dev->id.vendor  = 0x0001;
	input_dev->id.product = 0x0001;
	input_dev->id.version = 0x0100;
	input_dev->dev.parent = &serio->dev;

	input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_REP);
	input_dev->keycode = xtkbd->keycode;
	input_dev->keycodesize = sizeof(unsigned char);
	input_dev->keycodemax = ARRAY_SIZE(xtkbd_keycode);

	for (i = 0; i < 255; i++)
		set_bit(xtkbd->keycode[i], input_dev->keybit);
	clear_bit(0, input_dev->keybit);

	serio_set_drvdata(serio, xtkbd);

	err = serio_open(serio, drv);
	if (err)
		goto fail2;

	err = input_register_device(xtkbd->dev);
	if (err)
		goto fail3;

	return 0;

 fail3:	serio_close(serio);
 fail2:	serio_set_drvdata(serio, NULL);
 fail1:	input_free_device(input_dev);
	kfree(xtkbd);
	return err;
}

static void xtkbd_disconnect(struct serio *serio)
{
	struct xtkbd *xtkbd = serio_get_drvdata(serio);

	serio_close(serio);
	serio_set_drvdata(serio, NULL);
	input_unregister_device(xtkbd->dev);
	kfree(xtkbd);
}

static const struct serio_device_id xtkbd_serio_ids[] = {
	{
		.type	= SERIO_XT,
		.proto	= SERIO_ANY,
		.id	= SERIO_ANY,
		.extra	= SERIO_ANY,
	},
	{ 0 }
};

MODULE_DEVICE_TABLE(serio, xtkbd_serio_ids);

static struct serio_driver xtkbd_drv = {
	.driver		= {
		.name	= "xtkbd",
	},
	.description	= DRIVER_DESC,
	.id_table	= xtkbd_serio_ids,
	.interrupt	= xtkbd_interrupt,
	.connect	= xtkbd_connect,
	.disconnect	= xtkbd_disconnect,
};

module_serio_driver(xtkbd_drv);