// 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);