mac_hid.c

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/*
 * drivers/macintosh/mac_hid.c
 *
 * HID support stuff for Macintosh computers.
 *
 * Copyright (C) 2000 Franz Sirl.
 *
 * This file will soon be removed in favor of an uinput userspace tool.
 */

#include <linux/init.h>
#include <linux/proc_fs.h>
#include <linux/sysctl.h>
#include <linux/input.h>
#include <linux/module.h>
#include <linux/slab.h>

MODULE_LICENSE("GPL");

static int mouse_emulate_buttons;
static int mouse_button2_keycode = KEY_RIGHTCTRL;   /* right control key */
static int mouse_button3_keycode = KEY_RIGHTALT;    /* right option key */

static struct input_dev *mac_hid_emumouse_dev;

static DEFINE_MUTEX(mac_hid_emumouse_mutex);

static int mac_hid_create_emumouse(void)
{
    static struct lock_class_key mac_hid_emumouse_dev_event_class;
    static struct lock_class_key mac_hid_emumouse_dev_mutex_class;
    int err;

    mac_hid_emumouse_dev = input_allocate_device();
    if (!mac_hid_emumouse_dev)
        return -ENOMEM;

    lockdep_set_class(&mac_hid_emumouse_dev->event_lock,
              &mac_hid_emumouse_dev_event_class);
    lockdep_set_class(&mac_hid_emumouse_dev->mutex,
              &mac_hid_emumouse_dev_mutex_class);

    mac_hid_emumouse_dev->name = "Macintosh mouse button emulation";
    mac_hid_emumouse_dev->id.bustype = BUS_ADB;
    mac_hid_emumouse_dev->id.vendor = 0x0001;
    mac_hid_emumouse_dev->id.product = 0x0001;
    mac_hid_emumouse_dev->id.version = 0x0100;

    mac_hid_emumouse_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_REL);
    mac_hid_emumouse_dev->keybit[BIT_WORD(BTN_MOUSE)] =
        BIT_MASK(BTN_LEFT) | BIT_MASK(BTN_MIDDLE) | BIT_MASK(BTN_RIGHT);
    mac_hid_emumouse_dev->relbit[0] = BIT_MASK(REL_X) | BIT_MASK(REL_Y);

    err = input_register_device(mac_hid_emumouse_dev);
    if (err) {
        input_free_device(mac_hid_emumouse_dev);
        mac_hid_emumouse_dev = NULL;
        return err;
    }

    return 0;
}

static void mac_hid_destroy_emumouse(void)
{
    input_unregister_device(mac_hid_emumouse_dev);
    mac_hid_emumouse_dev = NULL;
}

static bool mac_hid_emumouse_filter(struct input_handle *handle,
                    unsigned int type, unsigned int code,
                    int value)
{
    unsigned int btn;

    if (type != EV_KEY)
        return false;

    if (code == mouse_button2_keycode)
        btn = BTN_MIDDLE;
    else if (code == mouse_button3_keycode)
        btn = BTN_RIGHT;
    else
        return false;

    input_report_key(mac_hid_emumouse_dev, btn, value);
    input_sync(mac_hid_emumouse_dev);

    return true;
}

static int mac_hid_emumouse_connect(struct input_handler *handler,
                    struct input_dev *dev,
                    const struct input_device_id *id)
{
    struct input_handle *handle;
    int error;

    /* Don't bind to ourselves */
    if (dev == mac_hid_emumouse_dev)
        return -ENODEV;

    handle = kzalloc(sizeof(struct input_handle), GFP_KERNEL);
    if (!handle)
        return -ENOMEM;

    handle->dev = dev;
    handle->handler = handler;
    handle->name = "mac-button-emul";

    error = input_register_handle(handle);
    if (error) {
        printk(KERN_ERR
            "mac_hid: Failed to register button emulation handle, "
            "error %d\n", error);
        goto err_free;
    }

    error = input_open_device(handle);
    if (error) {
        printk(KERN_ERR
            "mac_hid: Failed to open input device, error %d\n",
            error);
        goto err_unregister;
    }

    return 0;

 err_unregister:
    input_unregister_handle(handle);
 err_free:
    kfree(handle);
    return error;
}

static void mac_hid_emumouse_disconnect(struct input_handle *handle)
{
    input_close_device(handle);
    input_unregister_handle(handle);
    kfree(handle);
}

static const struct input_device_id mac_hid_emumouse_ids[] = {
    {
        .flags = INPUT_DEVICE_ID_MATCH_EVBIT,
        .evbit = { BIT_MASK(EV_KEY) },
    },
    { },
};

MODULE_DEVICE_TABLE(input, mac_hid_emumouse_ids);

static struct input_handler mac_hid_emumouse_handler = {
    .filter     = mac_hid_emumouse_filter,
    .connect    = mac_hid_emumouse_connect,
    .disconnect = mac_hid_emumouse_disconnect,
    .name       = "mac-button-emul",
    .id_table   = mac_hid_emumouse_ids,
};

static int mac_hid_start_emulation(void)
{
    int err;

    err = mac_hid_create_emumouse();
    if (err)
        return err;

    err = input_register_handler(&mac_hid_emumouse_handler);
    if (err) {
        mac_hid_destroy_emumouse();
        return err;
    }

    return 0;
}

static void mac_hid_stop_emulation(void)
{
    input_unregister_handler(&mac_hid_emumouse_handler);
    mac_hid_destroy_emumouse();
}

static int mac_hid_toggle_emumouse(ctl_table *table, int write,
                   void __user *buffer, size_t *lenp,
                   loff_t *ppos)
{
    int *valp = table->data;
    int old_val = *valp;
    int rc;

    rc = mutex_lock_killable(&mac_hid_emumouse_mutex);
    if (rc)
        return rc;

    rc = proc_dointvec(table, write, buffer, lenp, ppos);

    if (rc == 0 && write && *valp != old_val) {
        if (*valp == 1)
            rc = mac_hid_start_emulation();
        else if (*valp == 0)
            mac_hid_stop_emulation();
        else
            rc = -EINVAL;
    }

    /* Restore the old value in case of error */
    if (rc)
        *valp = old_val;

    mutex_unlock(&mac_hid_emumouse_mutex);

    return rc;
}

/* file(s) in /proc/sys/dev/mac_hid */
static ctl_table mac_hid_files[] = {
    {
        .procname   = "mouse_button_emulation",
        .data       = &mouse_emulate_buttons,
        .maxlen     = sizeof(int),
        .mode       = 0644,
        .proc_handler   = mac_hid_toggle_emumouse,
    },
    {
        .procname   = "mouse_button2_keycode",
        .data       = &mouse_button2_keycode,
        .maxlen     = sizeof(int),
        .mode       = 0644,
        .proc_handler   = proc_dointvec,
    },
    {
        .procname   = "mouse_button3_keycode",
        .data       = &mouse_button3_keycode,
        .maxlen     = sizeof(int),
        .mode       = 0644,
        .proc_handler   = proc_dointvec,
    },
    { }
};

/* dir in /proc/sys/dev */
static ctl_table mac_hid_dir[] = {
    {
        .procname   = "mac_hid",
        .maxlen     = 0,
        .mode       = 0555,
        .child      = mac_hid_files,
    },
    { }
};

/* /proc/sys/dev itself, in case that is not there yet */
static ctl_table mac_hid_root_dir[] = {
    {
        .procname   = "dev",
        .maxlen     = 0,
        .mode       = 0555,
        .child      = mac_hid_dir,
    },
    { }
};

static struct ctl_table_header *mac_hid_sysctl_header;

static int __init mac_hid_init(void)
{
    mac_hid_sysctl_header = register_sysctl_table(mac_hid_root_dir);
    if (!mac_hid_sysctl_header)
        return -ENOMEM;

    return 0;
}
module_init(mac_hid_init);

static void __exit mac_hid_exit(void)
{
    unregister_sysctl_table(mac_hid_sysctl_header);

    if (mouse_emulate_buttons)
        mac_hid_stop_emulation();
}
module_exit(mac_hid_exit);