dell-wmi-aio.c

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/*
 *  WMI hotkeys support for Dell All-In-One series
 *
 *  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
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

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

MODULE_DESCRIPTION("WMI hotkeys driver for Dell All-In-One series");
MODULE_LICENSE("GPL");

#define EVENT_GUID1 "284A0E6B-380E-472A-921F-E52786257FB4"
#define EVENT_GUID2 "02314822-307C-4F66-BF0E-48AEAEB26CC8"

static const char *dell_wmi_aio_guids[] = {
    EVENT_GUID1,
    EVENT_GUID2,
    NULL
};

MODULE_ALIAS("wmi:"EVENT_GUID1);
MODULE_ALIAS("wmi:"EVENT_GUID2);

static const struct key_entry dell_wmi_aio_keymap[] = {
    { KE_KEY, 0xc0, { KEY_VOLUMEUP } },
    { KE_KEY, 0xc1, { KEY_VOLUMEDOWN } },
    { KE_END, 0 }
};

static struct input_dev *dell_wmi_aio_input_dev;

static void dell_wmi_aio_notify(u32 value, void *context)
{
    struct acpi_buffer response = { ACPI_ALLOCATE_BUFFER, NULL };
    union acpi_object *obj;
    acpi_status status;

    status = wmi_get_event_data(value, &response);
    if (status != AE_OK) {
        pr_info("bad event status 0x%x\n", status);
        return;
    }

    obj = (union acpi_object *)response.pointer;
    if (obj) {
        unsigned int scancode;

        switch (obj->type) {
        case ACPI_TYPE_INTEGER:
            /* Most All-In-One correctly return integer scancode */
            scancode = obj->integer.value;
            sparse_keymap_report_event(dell_wmi_aio_input_dev,
                scancode, 1, true);
            break;
        case ACPI_TYPE_BUFFER:
            /* Broken machines return the scancode in a buffer */
            if (obj->buffer.pointer && obj->buffer.length > 0) {
                scancode = obj->buffer.pointer[0];
                sparse_keymap_report_event(
                    dell_wmi_aio_input_dev,
                    scancode, 1, true);
            }
            break;
        }
    }
    kfree(obj);
}

static int __init dell_wmi_aio_input_setup(void)
{
    int err;

    dell_wmi_aio_input_dev = input_allocate_device();

    if (!dell_wmi_aio_input_dev)
        return -ENOMEM;

    dell_wmi_aio_input_dev->name = "Dell AIO WMI hotkeys";
    dell_wmi_aio_input_dev->phys = "wmi/input0";
    dell_wmi_aio_input_dev->id.bustype = BUS_HOST;

    err = sparse_keymap_setup(dell_wmi_aio_input_dev,
            dell_wmi_aio_keymap, NULL);
    if (err) {
        pr_err("Unable to setup input device keymap\n");
        goto err_free_dev;
    }
    err = input_register_device(dell_wmi_aio_input_dev);
    if (err) {
        pr_info("Unable to register input device\n");
        goto err_free_keymap;
    }
    return 0;

err_free_keymap:
    sparse_keymap_free(dell_wmi_aio_input_dev);
err_free_dev:
    input_free_device(dell_wmi_aio_input_dev);
    return err;
}

static const char *dell_wmi_aio_find(void)
{
    int i;

    for (i = 0; dell_wmi_aio_guids[i] != NULL; i++)
        if (wmi_has_guid(dell_wmi_aio_guids[i]))
            return dell_wmi_aio_guids[i];

    return NULL;
}

static int __init dell_wmi_aio_init(void)
{
    int err;
    const char *guid;

    guid = dell_wmi_aio_find();
    if (!guid) {
        pr_warn("No known WMI GUID found\n");
        return -ENXIO;
    }

    err = dell_wmi_aio_input_setup();
    if (err)
        return err;

    err = wmi_install_notify_handler(guid, dell_wmi_aio_notify, NULL);
    if (err) {
        pr_err("Unable to register notify handler - %d\n", err);
        sparse_keymap_free(dell_wmi_aio_input_dev);
        input_unregister_device(dell_wmi_aio_input_dev);
        return err;
    }

    return 0;
}

static void __exit dell_wmi_aio_exit(void)
{
    const char *guid;

    guid = dell_wmi_aio_find();
    wmi_remove_notify_handler(guid);
    sparse_keymap_free(dell_wmi_aio_input_dev);
    input_unregister_device(dell_wmi_aio_input_dev);
}

module_init(dell_wmi_aio_init);
module_exit(dell_wmi_aio_exit);