// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Stowaway keyboard driver for Linux
 */

/*
 *  Copyright (c) 2006 Marek Vasut
 *
 *  Based on Newton keyboard driver for Linux
 *  by Justin Cormack
 */

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

#define DRIVER_DESC     "Stowaway keyboard driver"

MODULE_AUTHOR("Marek Vasut <marek.vasut@gmail.com>");
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");

#define SKBD_KEY_MASK   0x7f
#define SKBD_RELEASE    0x80

static unsigned char skbd_keycode[128] = {
        KEY_1, KEY_2, KEY_3, KEY_Z, KEY_4, KEY_5, KEY_6, KEY_7,
        0, KEY_Q, KEY_W, KEY_E, KEY_R, KEY_T, KEY_Y, KEY_GRAVE,
        KEY_X, KEY_A, KEY_S, KEY_D, KEY_F, KEY_G, KEY_H, KEY_SPACE,
        KEY_CAPSLOCK, KEY_TAB, KEY_LEFTCTRL, 0, 0, 0, 0, 0,
        0, 0, 0, KEY_LEFTALT, 0, 0, 0, 0,
        0, 0, 0, 0, KEY_C, KEY_V, KEY_B, KEY_N,
        KEY_MINUS, KEY_EQUAL, KEY_BACKSPACE, KEY_HOME, KEY_8, KEY_9, KEY_0, KEY_ESC,
        KEY_LEFTBRACE, KEY_RIGHTBRACE, KEY_BACKSLASH, KEY_END, KEY_U, KEY_I, KEY_O, KEY_P,
        KEY_APOSTROPHE, KEY_ENTER, KEY_PAGEUP,0, KEY_J, KEY_K, KEY_L, KEY_SEMICOLON,
        KEY_SLASH, KEY_UP, KEY_PAGEDOWN, 0,KEY_M, KEY_COMMA, KEY_DOT, KEY_INSERT,
        KEY_DELETE, KEY_LEFT, KEY_DOWN, KEY_RIGHT,  0, 0, 0,
        KEY_LEFTSHIFT, KEY_RIGHTSHIFT, 0, 0, 0, 0, 0,
        0, 0, 0, 0, 0, 0, 0, 0,
        0, 0, 0, 0, 0, 0, 0, 0,
        0, KEY_F1, KEY_F2, KEY_F3, KEY_F4, KEY_F5, KEY_F6, KEY_F7,
        KEY_F8, KEY_F9, KEY_F10, KEY_F11, KEY_F12, 0, 0, 0
};

struct skbd {
        unsigned char keycode[128];
        struct input_dev *dev;
        struct serio *serio;
        char phys[32];
};

static irqreturn_t skbd_interrupt(struct serio *serio, unsigned char data,
                                  unsigned int flags)
{
        struct skbd *skbd = serio_get_drvdata(serio);
        struct input_dev *dev = skbd->dev;

        if (skbd->keycode[data & SKBD_KEY_MASK]) {
                input_report_key(dev, skbd->keycode[data & SKBD_KEY_MASK],
                                 !(data & SKBD_RELEASE));
                input_sync(dev);
        }

        return IRQ_HANDLED;
}

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

        skbd = kzalloc_obj(*skbd);
        input_dev = input_allocate_device();
        if (!skbd || !input_dev)
                goto fail1;

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

        input_dev->name = "Stowaway Keyboard";
        input_dev->phys = skbd->phys;
        input_dev->id.bustype = BUS_RS232;
        input_dev->id.vendor = SERIO_STOWAWAY;
        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 = skbd->keycode;
        input_dev->keycodesize = sizeof(unsigned char);
        input_dev->keycodemax = ARRAY_SIZE(skbd_keycode);
        for (i = 0; i < ARRAY_SIZE(skbd_keycode); i++)
                set_bit(skbd_keycode[i], input_dev->keybit);
        clear_bit(0, input_dev->keybit);

        serio_set_drvdata(serio, skbd);

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

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

        return 0;

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

static void skbd_disconnect(struct serio *serio)
{
        struct skbd *skbd = serio_get_drvdata(serio);

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

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

MODULE_DEVICE_TABLE(serio, skbd_serio_ids);

static struct serio_driver skbd_drv = {
        .driver         = {
                .name   = "stowaway",
        },
        .description    = DRIVER_DESC,
        .id_table       = skbd_serio_ids,
        .interrupt      = skbd_interrupt,
        .connect        = skbd_connect,
        .disconnect     = skbd_disconnect,
};

module_serio_driver(skbd_drv);