/*
 * Dell WMI hotkeys
 *
 * Copyright (C) 2008 Red Hat <mjg@redhat.com>
 *
 * Portions based on wistron_btns.c:
 * Copyright (C) 2005 Miloslav Trmac <mitr@volny.cz>
 * Copyright (C) 2005 Bernhard Rosenkraenzer <bero@arklinux.org>
 * Copyright (C) 2005 Dmitry Torokhov <dtor@mail.ru>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/input.h>
#include <acpi/acpi_drivers.h>
#include <linux/acpi.h>
#include <linux/string.h>

MODULE_AUTHOR("Matthew Garrett <mjg@redhat.com>");
MODULE_DESCRIPTION("Dell laptop WMI hotkeys driver");
MODULE_LICENSE("GPL");

#define DELL_EVENT_GUID "9DBB5994-A997-11DA-B012-B622A1EF5492"

MODULE_ALIAS("wmi:"DELL_EVENT_GUID);

struct key_entry {
        char type;              /* See KE_* below */
        u16 code;
        u16 keycode;
};

enum { KE_KEY, KE_SW, KE_IGNORE, KE_END };

/*
 * Certain keys are flagged as KE_IGNORE. All of these are either
 * notifications (rather than requests for change) or are also sent
 * via the keyboard controller so should not be sent again.
 */

static struct key_entry dell_wmi_keymap[] = {
        {KE_KEY, 0xe045, KEY_PROG1},
        {KE_KEY, 0xe009, KEY_EJECTCD},

        /* These also contain the brightness level at offset 6 */
        {KE_KEY, 0xe006, KEY_BRIGHTNESSUP},
        {KE_KEY, 0xe005, KEY_BRIGHTNESSDOWN},

        /* Battery health status button */
        {KE_KEY, 0xe007, KEY_BATTERY},

        /* This is actually for all radios. Although physically a
         * switch, the notification does not provide an indication of
         * state and so it should be reported as a key */
        {KE_KEY, 0xe008, KEY_WLAN},

        /* The next device is at offset 6, the active devices are at
           offset 8 and the attached devices at offset 10 */
        {KE_KEY, 0xe00b, KEY_DISPLAYTOGGLE},

        {KE_IGNORE, 0xe00c, KEY_KBDILLUMTOGGLE},

        /* BIOS error detected */
        {KE_IGNORE, 0xe00d, KEY_RESERVED},

        /* Wifi Catcher */
        {KE_KEY, 0xe011, KEY_PROG2},

        /* Ambient light sensor toggle */
        {KE_IGNORE, 0xe013, KEY_RESERVED},

        {KE_IGNORE, 0xe020, KEY_MUTE},
        {KE_IGNORE, 0xe02e, KEY_VOLUMEDOWN},
        {KE_IGNORE, 0xe030, KEY_VOLUMEUP},
        {KE_IGNORE, 0xe033, KEY_KBDILLUMUP},
        {KE_IGNORE, 0xe034, KEY_KBDILLUMDOWN},
        {KE_IGNORE, 0xe03a, KEY_CAPSLOCK},
        {KE_IGNORE, 0xe045, KEY_NUMLOCK},
        {KE_IGNORE, 0xe046, KEY_SCROLLLOCK},
        {KE_END, 0}
};

static struct input_dev *dell_wmi_input_dev;

static struct key_entry *dell_wmi_get_entry_by_scancode(int code)
{
        struct key_entry *key;

        for (key = dell_wmi_keymap; key->type != KE_END; key++)
                if (code == key->code)
                        return key;

        return NULL;
}

static struct key_entry *dell_wmi_get_entry_by_keycode(int keycode)
{
        struct key_entry *key;

        for (key = dell_wmi_keymap; key->type != KE_END; key++)
                if (key->type == KE_KEY && keycode == key->keycode)
                        return key;

        return NULL;
}

static int dell_wmi_getkeycode(struct input_dev *dev, int scancode,
                               int *keycode)
{
        struct key_entry *key = dell_wmi_get_entry_by_scancode(scancode);

        if (key && key->type == KE_KEY) {
                *keycode = key->keycode;
                return 0;
        }

        return -EINVAL;
}

static int dell_wmi_setkeycode(struct input_dev *dev, int scancode, int keycode)
{
        struct key_entry *key;
        int old_keycode;

        if (keycode < 0 || keycode > KEY_MAX)
                return -EINVAL;

        key = dell_wmi_get_entry_by_scancode(scancode);
        if (key && key->type == KE_KEY) {
                old_keycode = key->keycode;
                key->keycode = keycode;
                set_bit(keycode, dev->keybit);
                if (!dell_wmi_get_entry_by_keycode(old_keycode))
                        clear_bit(old_keycode, dev->keybit);
                return 0;
        }
        return -EINVAL;
}

static void dell_wmi_notify(u32 value, void *context)
{
        struct acpi_buffer response = { ACPI_ALLOCATE_BUFFER, NULL };
        static struct key_entry *key;
        union acpi_object *obj;

        wmi_get_event_data(value, &response);

        obj = (union acpi_object *)response.pointer;

        if (obj && obj->type == ACPI_TYPE_BUFFER) {
                int *buffer = (int *)obj->buffer.pointer;
                /*
                 *  The upper bytes of the event may contain
                 *  additional information, so mask them off for the
                 *  scancode lookup
                 */
                key = dell_wmi_get_entry_by_scancode(buffer[1] & 0xFFFF);
                if (key) {
                        input_report_key(dell_wmi_input_dev, key->keycode, 1);
                        input_sync(dell_wmi_input_dev);
                        input_report_key(dell_wmi_input_dev, key->keycode, 0);
                        input_sync(dell_wmi_input_dev);
                } else if (buffer[1] & 0xFFFF)
                        printk(KERN_INFO "dell-wmi: Unknown key %x pressed\n",
                               buffer[1] & 0xFFFF);
        }
}

static int __init dell_wmi_input_setup(void)
{
        struct key_entry *key;
        int err;

        dell_wmi_input_dev = input_allocate_device();

        if (!dell_wmi_input_dev)
                return -ENOMEM;

        dell_wmi_input_dev->name = "Dell WMI hotkeys";
        dell_wmi_input_dev->phys = "wmi/input0";
        dell_wmi_input_dev->id.bustype = BUS_HOST;
        dell_wmi_input_dev->getkeycode = dell_wmi_getkeycode;
        dell_wmi_input_dev->setkeycode = dell_wmi_setkeycode;

        for (key = dell_wmi_keymap; key->type != KE_END; key++) {
                switch (key->type) {
                case KE_KEY:
                        set_bit(EV_KEY, dell_wmi_input_dev->evbit);
                        set_bit(key->keycode, dell_wmi_input_dev->keybit);
                        break;
                case KE_SW:
                        set_bit(EV_SW, dell_wmi_input_dev->evbit);
                        set_bit(key->keycode, dell_wmi_input_dev->swbit);
                        break;
                }
        }

        err = input_register_device(dell_wmi_input_dev);

        if (err) {
                input_free_device(dell_wmi_input_dev);
                return err;
        }

        return 0;
}

static int __init dell_wmi_init(void)
{
        int err;

        if (wmi_has_guid(DELL_EVENT_GUID)) {
                err = dell_wmi_input_setup();

                if (err)
                        return err;

                err = wmi_install_notify_handler(DELL_EVENT_GUID,
                                                 dell_wmi_notify, NULL);
                if (err) {
                        input_unregister_device(dell_wmi_input_dev);
                        printk(KERN_ERR "dell-wmi: Unable to register"
                               " notify handler - %d\n", err);
                        return err;
                }

        } else
                printk(KERN_WARNING "dell-wmi: No known WMI GUID found\n");

        return 0;
}

static void __exit dell_wmi_exit(void)
{
        if (wmi_has_guid(DELL_EVENT_GUID)) {
                wmi_remove_notify_handler(DELL_EVENT_GUID);
                input_unregister_device(dell_wmi_input_dev);
        }
}

module_init(dell_wmi_init);
module_exit(dell_wmi_exit);