// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  Copyright (c) 1999-2001 Vojtech Pavlik
 *
 *  Based on the work of:
 *      David Thompson
 *      Joseph Krahn
 */

/*
 * SpaceTec SpaceBall 2003/3003/4000 FLX driver for Linux
 */

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

#define DRIVER_DESC     "SpaceTec SpaceBall 2003/3003/4000 FLX driver"

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

/*
 * Constants.
 */

#define SPACEBALL_MAX_LENGTH    128
#define SPACEBALL_MAX_ID        9

#define SPACEBALL_1003      1
#define SPACEBALL_2003B     3
#define SPACEBALL_2003C     4
#define SPACEBALL_3003C     7
#define SPACEBALL_4000FLX   8
#define SPACEBALL_4000FLX_L 9

static int spaceball_axes[] = { ABS_X, ABS_Z, ABS_Y, ABS_RX, ABS_RZ, ABS_RY };
static char *spaceball_names[] = {
        "?", "SpaceTec SpaceBall 1003", "SpaceTec SpaceBall 2003", "SpaceTec SpaceBall 2003B",
        "SpaceTec SpaceBall 2003C", "SpaceTec SpaceBall 3003", "SpaceTec SpaceBall SpaceController",
        "SpaceTec SpaceBall 3003C", "SpaceTec SpaceBall 4000FLX", "SpaceTec SpaceBall 4000FLX Lefty" };

/*
 * Per-Ball data.
 */

struct spaceball {
        struct input_dev *dev;
        int idx;
        int escape;
        unsigned char data[SPACEBALL_MAX_LENGTH];
        char phys[32];
};

/*
 * spaceball_process_packet() decodes packets the driver receives from the
 * SpaceBall.
 */

static void spaceball_process_packet(struct spaceball* spaceball)
{
        struct input_dev *dev = spaceball->dev;
        unsigned char *data = spaceball->data;
        int i;

        if (spaceball->idx < 2) return;

        switch (spaceball->data[0]) {

                case 'D':                                       /* Ball data */
                        if (spaceball->idx != 15) return;
                        /*
                         * Skip first three bytes; read six axes worth of data.
                         * Axis values are signed 16-bit big-endian.
                         */
                        data += 3;
                        for (i = 0; i < ARRAY_SIZE(spaceball_axes); i++) {
                                input_report_abs(dev, spaceball_axes[i],
                                        (__s16)get_unaligned_be16(&data[i * 2]));
                        }
                        break;

                case 'K':                                       /* Button data */
                        if (spaceball->idx != 3) return;
                        input_report_key(dev, BTN_1, (data[2] & 0x01) || (data[2] & 0x20));
                        input_report_key(dev, BTN_2, data[2] & 0x02);
                        input_report_key(dev, BTN_3, data[2] & 0x04);
                        input_report_key(dev, BTN_4, data[2] & 0x08);
                        input_report_key(dev, BTN_5, data[1] & 0x01);
                        input_report_key(dev, BTN_6, data[1] & 0x02);
                        input_report_key(dev, BTN_7, data[1] & 0x04);
                        input_report_key(dev, BTN_8, data[1] & 0x10);
                        break;

                case '.':                                       /* Advanced button data */
                        if (spaceball->idx != 3) return;
                        input_report_key(dev, BTN_1, data[2] & 0x01);
                        input_report_key(dev, BTN_2, data[2] & 0x02);
                        input_report_key(dev, BTN_3, data[2] & 0x04);
                        input_report_key(dev, BTN_4, data[2] & 0x08);
                        input_report_key(dev, BTN_5, data[2] & 0x10);
                        input_report_key(dev, BTN_6, data[2] & 0x20);
                        input_report_key(dev, BTN_7, data[2] & 0x80);
                        input_report_key(dev, BTN_8, data[1] & 0x01);
                        input_report_key(dev, BTN_9, data[1] & 0x02);
                        input_report_key(dev, BTN_A, data[1] & 0x04);
                        input_report_key(dev, BTN_B, data[1] & 0x08);
                        input_report_key(dev, BTN_C, data[1] & 0x10);
                        input_report_key(dev, BTN_MODE, data[1] & 0x20);
                        break;

                case 'E':                                       /* Device error */
                        spaceball->data[spaceball->idx - 1] = 0;
                        printk(KERN_ERR "spaceball: Device error. [%s]\n", spaceball->data + 1);
                        break;

                case '?':                                       /* Bad command packet */
                        spaceball->data[spaceball->idx - 1] = 0;
                        printk(KERN_ERR "spaceball: Bad command. [%s]\n", spaceball->data + 1);
                        break;
        }

        input_sync(dev);
}

/*
 * Spaceball 4000 FLX packets all start with a one letter packet-type decriptor,
 * and end in 0x0d. It uses '^' as an escape for CR, XOFF and XON characters which
 * can occur in the axis values.
 */

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

        switch (data) {
                case 0xd:
                        spaceball_process_packet(spaceball);
                        spaceball->idx = 0;
                        spaceball->escape = 0;
                        break;
                case '^':
                        if (!spaceball->escape) {
                                spaceball->escape = 1;
                                break;
                        }
                        spaceball->escape = 0;
                        fallthrough;
                case 'M':
                case 'Q':
                case 'S':
                        if (spaceball->escape) {
                                spaceball->escape = 0;
                                data &= 0x1f;
                        }
                        fallthrough;
                default:
                        if (spaceball->escape)
                                spaceball->escape = 0;
                        if (spaceball->idx < SPACEBALL_MAX_LENGTH)
                                spaceball->data[spaceball->idx++] = data;
                        break;
        }
        return IRQ_HANDLED;
}

/*
 * spaceball_disconnect() is the opposite of spaceball_connect()
 */

static void spaceball_disconnect(struct serio *serio)
{
        struct spaceball* spaceball = serio_get_drvdata(serio);

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

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

static int spaceball_connect(struct serio *serio, struct serio_driver *drv)
{
        struct spaceball *spaceball;
        struct input_dev *input_dev;
        int err = -ENOMEM;
        int i, id;

        if ((id = serio->id.id) > SPACEBALL_MAX_ID)
                return -ENODEV;

        spaceball = kmalloc_obj(*spaceball);
        input_dev = input_allocate_device();
        if (!spaceball || !input_dev)
                goto fail1;

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

        input_dev->name = spaceball_names[id];
        input_dev->phys = spaceball->phys;
        input_dev->id.bustype = BUS_RS232;
        input_dev->id.vendor = SERIO_SPACEBALL;
        input_dev->id.product = id;
        input_dev->id.version = 0x0100;
        input_dev->dev.parent = &serio->dev;

        input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);

        switch (id) {
                case SPACEBALL_4000FLX:
                case SPACEBALL_4000FLX_L:
                        input_dev->keybit[BIT_WORD(BTN_0)] |= BIT_MASK(BTN_9);
                        input_dev->keybit[BIT_WORD(BTN_A)] |= BIT_MASK(BTN_A) |
                                BIT_MASK(BTN_B) | BIT_MASK(BTN_C) |
                                BIT_MASK(BTN_MODE);
                        fallthrough;
                default:
                        input_dev->keybit[BIT_WORD(BTN_0)] |= BIT_MASK(BTN_2) |
                                BIT_MASK(BTN_3) | BIT_MASK(BTN_4) |
                                BIT_MASK(BTN_5) | BIT_MASK(BTN_6) |
                                BIT_MASK(BTN_7) | BIT_MASK(BTN_8);
                        fallthrough;
                case SPACEBALL_3003C:
                        input_dev->keybit[BIT_WORD(BTN_0)] |= BIT_MASK(BTN_1) |
                                BIT_MASK(BTN_8);
        }

        for (i = 0; i < 3; i++) {
                input_set_abs_params(input_dev, ABS_X + i, -8000, 8000, 8, 40);
                input_set_abs_params(input_dev, ABS_RX + i, -1600, 1600, 2, 8);
        }

        serio_set_drvdata(serio, spaceball);

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

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

        return 0;

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

/*
 * The serio driver structure.
 */

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

MODULE_DEVICE_TABLE(serio, spaceball_serio_ids);

static struct serio_driver spaceball_drv = {
        .driver         = {
                .name   = "spaceball",
        },
        .description    = DRIVER_DESC,
        .id_table       = spaceball_serio_ids,
        .interrupt      = spaceball_interrupt,
        .connect        = spaceball_connect,
        .disconnect     = spaceball_disconnect,
};

module_serio_driver(spaceball_drv);