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

/*
 * Magellan and Space Mouse 6dof controller driver for Linux
 */

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

#define DRIVER_DESC	"Magellan and SpaceMouse 6dof controller driver"

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

/*
 * Definitions & global arrays.
 */

#define	MAGELLAN_MAX_LENGTH	32

static int magellan_buttons[] = { BTN_0, BTN_1, BTN_2, BTN_3, BTN_4, BTN_5, BTN_6, BTN_7, BTN_8 };
static int magellan_axes[] = { ABS_X, ABS_Y, ABS_Z, ABS_RX, ABS_RY, ABS_RZ };

/*
 * Per-Magellan data.
 */

struct magellan {
	struct input_dev *dev;
	int idx;
	unsigned char data[MAGELLAN_MAX_LENGTH];
	char phys[32];
};

/*
 * magellan_crunch_nibbles() verifies that the bytes sent from the Magellan
 * have correct upper nibbles for the lower ones, if not, the packet will
 * be thrown away. It also strips these upper halves to simplify further
 * processing.
 */

static int magellan_crunch_nibbles(unsigned char *data, int count)
{
	static unsigned char nibbles[16] = "0AB3D56GH9:K<MN?";

	do {
		if (data[count] == nibbles[data[count] & 0xf])
			data[count] = data[count] & 0xf;
		else
			return -1;
	} while (--count);

	return 0;
}

static void magellan_process_packet(struct magellan* magellan)
{
	struct input_dev *dev = magellan->dev;
	unsigned char *data = magellan->data;
	int i, t;

	if (!magellan->idx) return;

	switch (magellan->data[0]) {

		case 'd':				/* Axis data */
			if (magellan->idx != 25) return;
			if (magellan_crunch_nibbles(data, 24)) return;
			for (i = 0; i < 6; i++)
				input_report_abs(dev, magellan_axes[i],
					(data[(i << 2) + 1] << 12 | data[(i << 2) + 2] << 8 |
					 data[(i << 2) + 3] <<  4 | data[(i << 2) + 4]) - 32768);
			break;

		case 'k':				/* Button data */
			if (magellan->idx != 4) return;
			if (magellan_crunch_nibbles(data, 3)) return;
			t = (data[1] << 1) | (data[2] << 5) | data[3];
			for (i = 0; i < 9; i++) input_report_key(dev, magellan_buttons[i], (t >> i) & 1);
			break;
	}

	input_sync(dev);
}

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

	if (data == '\r') {
		magellan_process_packet(magellan);
		magellan->idx = 0;
	} else {
		if (magellan->idx < MAGELLAN_MAX_LENGTH)
			magellan->data[magellan->idx++] = data;
	}
	return IRQ_HANDLED;
}

/*
 * magellan_disconnect() is the opposite of magellan_connect()
 */

static void magellan_disconnect(struct serio *serio)
{
	struct magellan* magellan = serio_get_drvdata(serio);

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

/*
 * magellan_connect() is the routine that is called when someone adds a
 * new serio device that supports Magellan protocol and registers it as
 * an input device.
 */

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

	magellan = kzalloc(sizeof(struct magellan), GFP_KERNEL);
	input_dev = input_allocate_device();
	if (!magellan || !input_dev)
		goto fail1;

	magellan->dev = input_dev;
	snprintf(magellan->phys, sizeof(magellan->phys), "%s/input0", serio->phys);

	input_dev->name = "LogiCad3D Magellan / SpaceMouse";
	input_dev->phys = magellan->phys;
	input_dev->id.bustype = BUS_RS232;
	input_dev->id.vendor = SERIO_MAGELLAN;
	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_ABS);

	for (i = 0; i < 9; i++)
		set_bit(magellan_buttons[i], input_dev->keybit);

	for (i = 0; i < 6; i++)
		input_set_abs_params(input_dev, magellan_axes[i], -360, 360, 0, 0);

	serio_set_drvdata(serio, magellan);

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

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

	return 0;

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

/*
 * The serio driver structure.
 */

static const struct serio_device_id magellan_serio_ids[] = {
	{
		.type	= SERIO_RS232,
		.proto	= SERIO_MAGELLAN,
		.id	= SERIO_ANY,
		.extra	= SERIO_ANY,
	},
	{ 0 }
};

MODULE_DEVICE_TABLE(serio, magellan_serio_ids);

static struct serio_driver magellan_drv = {
	.driver		= {
		.name	= "magellan",
	},
	.description	= DRIVER_DESC,
	.id_table	= magellan_serio_ids,
	.interrupt	= magellan_interrupt,
	.connect	= magellan_connect,
	.disconnect	= magellan_disconnect,
};

module_serio_driver(magellan_drv);