// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  button.c - ACPI Button Driver
 *
 *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
 *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
 */

#define pr_fmt(fmt) "ACPI: button: " fmt

#include <linux/compiler.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/input.h>
#include <linux/slab.h>
#include <linux/acpi.h>
#include <linux/dmi.h>
#include <linux/platform_device.h>
#include <acpi/button.h>

#define ACPI_BUTTON_CLASS               "button"
#define ACPI_BUTTON_FILE_STATE          "state"
#define ACPI_BUTTON_TYPE_UNKNOWN        0x00
#define ACPI_BUTTON_NOTIFY_WAKE         0x02
#define ACPI_BUTTON_NOTIFY_STATUS       0x80

#define ACPI_BUTTON_SUBCLASS_POWER      "power"
#define ACPI_BUTTON_DEVICE_NAME_POWER   "Power Button"
#define ACPI_BUTTON_TYPE_POWER          0x01

#define ACPI_BUTTON_SUBCLASS_SLEEP      "sleep"
#define ACPI_BUTTON_DEVICE_NAME_SLEEP   "Sleep Button"
#define ACPI_BUTTON_TYPE_SLEEP          0x03

#define ACPI_BUTTON_SUBCLASS_LID        "lid"
#define ACPI_BUTTON_DEVICE_NAME_LID     "Lid Switch"
#define ACPI_BUTTON_TYPE_LID            0x05

enum {
        ACPI_BUTTON_LID_INIT_IGNORE,
        ACPI_BUTTON_LID_INIT_OPEN,
        ACPI_BUTTON_LID_INIT_METHOD,
        ACPI_BUTTON_LID_INIT_DISABLED,
};

static const char * const lid_init_state_str[] = {
        [ACPI_BUTTON_LID_INIT_IGNORE]           = "ignore",
        [ACPI_BUTTON_LID_INIT_OPEN]             = "open",
        [ACPI_BUTTON_LID_INIT_METHOD]           = "method",
        [ACPI_BUTTON_LID_INIT_DISABLED]         = "disabled",
};

MODULE_AUTHOR("Paul Diefenbaugh");
MODULE_DESCRIPTION("ACPI Button Driver");
MODULE_LICENSE("GPL");

static const struct acpi_device_id button_device_ids[] = {
        {ACPI_BUTTON_HID_LID,    0},
        {ACPI_BUTTON_HID_SLEEP,  0},
        {ACPI_BUTTON_HID_SLEEPF, 0},
        {ACPI_BUTTON_HID_POWER,  0},
        {ACPI_BUTTON_HID_POWERF, 0},
        {"", 0},
};
MODULE_DEVICE_TABLE(acpi, button_device_ids);

/* Please keep this list sorted alphabetically by vendor and model */
static const struct dmi_system_id dmi_lid_quirks[] = {
        {
                /* GP-electronic T701, _LID method points to a floating GPIO */
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Insyde"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "T701"),
                        DMI_MATCH(DMI_BIOS_VERSION, "BYT70A.YNCHENG.WIN.007"),
                },
                .driver_data = (void *)(long)ACPI_BUTTON_LID_INIT_DISABLED,
        },
        {
                /* Nextbook Ares 8A tablet, _LID device always reports lid closed */
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Insyde"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "CherryTrail"),
                        DMI_MATCH(DMI_BIOS_VERSION, "M882"),
                },
                .driver_data = (void *)(long)ACPI_BUTTON_LID_INIT_DISABLED,
        },
        {
                /*
                 * Lenovo Yoga 9 14ITL5, initial notification of the LID device
                 * never happens.
                 */
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "82BG"),
                },
                .driver_data = (void *)(long)ACPI_BUTTON_LID_INIT_OPEN,
        },
        {
                /*
                 * Medion Akoya E2215T, notification of the LID device only
                 * happens on close, not on open and _LID always returns closed.
                 */
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "MEDION"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "E2215T"),
                },
                .driver_data = (void *)(long)ACPI_BUTTON_LID_INIT_OPEN,
        },
        {
                /*
                 * Medion Akoya E2228T, notification of the LID device only
                 * happens on close, not on open and _LID always returns closed.
                 */
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "MEDION"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "E2228T"),
                },
                .driver_data = (void *)(long)ACPI_BUTTON_LID_INIT_OPEN,
        },
        {
                /*
                 * Razer Blade Stealth 13 late 2019, notification of the LID device
                 * only happens on close, not on open and _LID always returns closed.
                 */
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Razer"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "Razer Blade Stealth 13 Late 2019"),
                },
                .driver_data = (void *)(long)ACPI_BUTTON_LID_INIT_OPEN,
        },
        {
                /*
                 * Samsung galaxybook2 ,initial _LID device notification returns
                 * lid closed.
                 */
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
                        DMI_MATCH(DMI_PRODUCT_NAME, "750XED"),
                },
                .driver_data = (void *)(long)ACPI_BUTTON_LID_INIT_OPEN,
        },
        {}
};

static int acpi_button_probe(struct platform_device *pdev);
static void acpi_button_remove(struct platform_device *pdev);

#ifdef CONFIG_PM_SLEEP
static int acpi_button_suspend(struct device *dev);
static int acpi_button_resume(struct device *dev);
#else
#define acpi_button_suspend NULL
#define acpi_button_resume NULL
#endif
static SIMPLE_DEV_PM_OPS(acpi_button_pm, acpi_button_suspend, acpi_button_resume);

static struct platform_driver acpi_button_driver = {
        .probe = acpi_button_probe,
        .remove = acpi_button_remove,
        .driver = {
                .name = "acpi-button",
                .acpi_match_table = button_device_ids,
                .pm = &acpi_button_pm,
        },
};

struct acpi_button {
        struct acpi_device *adev;
        struct device *dev;             /* physical button device */
        unsigned int type;
        struct input_dev *input;
        char phys[32];                  /* for input device */
        unsigned long pushed;
        int last_state;
        ktime_t last_time;
        bool suspended;
        bool lid_state_initialized;
};

static struct acpi_device *lid_device;
static long lid_init_state = -1;

static unsigned long lid_report_interval __read_mostly = 500;
module_param(lid_report_interval, ulong, 0644);
MODULE_PARM_DESC(lid_report_interval, "Interval (ms) between lid key events");

/* FS Interface (/proc) */
static struct proc_dir_entry *acpi_button_dir;
static struct proc_dir_entry *acpi_lid_dir;

static int acpi_lid_evaluate_state(struct acpi_device *device)
{
        unsigned long long lid_state;
        acpi_status status;

        status = acpi_evaluate_integer(device->handle, "_LID", NULL, &lid_state);
        if (ACPI_FAILURE(status))
                return -ENODEV;

        return lid_state ? 1 : 0;
}

static int acpi_lid_notify_state(struct acpi_button *button, int state)
{
        struct acpi_device *device = button->adev;
        ktime_t next_report;
        bool do_update;

        /*
         * In lid_init_state=ignore mode, if user opens/closes lid
         * frequently with "open" missing, and "last_time" is also updated
         * frequently, "close" cannot be delivered to the userspace.
         * So "last_time" is only updated after a timeout or an actual
         * switch.
         */
        if (lid_init_state != ACPI_BUTTON_LID_INIT_IGNORE ||
            button->last_state != !!state)
                do_update = true;
        else
                do_update = false;

        next_report = ktime_add(button->last_time,
                                ms_to_ktime(lid_report_interval));
        if (button->last_state == !!state &&
            ktime_after(ktime_get(), next_report)) {
                /* Complain the buggy firmware */
                pr_warn_once("The lid device is not compliant to SW_LID.\n");

                /*
                 * Send the unreliable complement switch event:
                 *
                 * On most platforms, the lid device is reliable. However
                 * there are exceptions:
                 * 1. Platforms returning initial lid state as "close" by
                 *    default after booting/resuming:
                 *     https://bugzilla.kernel.org/show_bug.cgi?id=89211
                 *     https://bugzilla.kernel.org/show_bug.cgi?id=106151
                 * 2. Platforms never reporting "open" events:
                 *     https://bugzilla.kernel.org/show_bug.cgi?id=106941
                 * On these buggy platforms, the usage model of the ACPI
                 * lid device actually is:
                 * 1. The initial returning value of _LID may not be
                 *    reliable.
                 * 2. The open event may not be reliable.
                 * 3. The close event is reliable.
                 *
                 * But SW_LID is typed as input switch event, the input
                 * layer checks if the event is redundant. Hence if the
                 * state is not switched, the userspace cannot see this
                 * platform triggered reliable event. By inserting a
                 * complement switch event, it then is guaranteed that the
                 * platform triggered reliable one can always be seen by
                 * the userspace.
                 */
                if (lid_init_state == ACPI_BUTTON_LID_INIT_IGNORE) {
                        do_update = true;
                        /*
                         * Do generate complement switch event for "close"
                         * as "close" is reliable and wrong "open" won't
                         * trigger unexpected behaviors.
                         * Do not generate complement switch event for
                         * "open" as "open" is not reliable and wrong
                         * "close" will trigger unexpected behaviors.
                         */
                        if (!state) {
                                input_report_switch(button->input,
                                                    SW_LID, state);
                                input_sync(button->input);
                        }
                }
        }
        /* Send the platform triggered reliable event */
        if (do_update) {
                acpi_handle_debug(device->handle, "ACPI LID %s\n",
                                  state ? "open" : "closed");
                input_report_switch(button->input, SW_LID, !state);
                input_sync(button->input);
                button->last_state = !!state;
                button->last_time = ktime_get();
        }

        return 0;
}

static int __maybe_unused acpi_button_state_seq_show(struct seq_file *seq,
                                                     void *offset)
{
        struct acpi_button *button = seq->private;
        int state;

        state = acpi_lid_evaluate_state(button->adev);
        seq_printf(seq, "state:      %s\n",
                   state < 0 ? "unsupported" : (state ? "open" : "closed"));
        return 0;
}

static int acpi_button_add_fs(struct acpi_button *button)
{
        struct acpi_device *device = button->adev;
        struct proc_dir_entry *entry = NULL;
        int ret = 0;

        /* procfs I/F for ACPI lid device only */
        if (button->type != ACPI_BUTTON_TYPE_LID)
                return 0;

        if (acpi_button_dir || acpi_lid_dir) {
                pr_info("More than one Lid device found!\n");
                return -EEXIST;
        }

        /* create /proc/acpi/button */
        acpi_button_dir = proc_mkdir(ACPI_BUTTON_CLASS, acpi_root_dir);
        if (!acpi_button_dir)
                return -ENODEV;

        /* create /proc/acpi/button/lid */
        acpi_lid_dir = proc_mkdir(ACPI_BUTTON_SUBCLASS_LID, acpi_button_dir);
        if (!acpi_lid_dir) {
                ret = -ENODEV;
                goto remove_button_dir;
        }

        /* create /proc/acpi/button/lid/LID/ */
        acpi_device_dir(device) = proc_mkdir(acpi_device_bid(device), acpi_lid_dir);
        if (!acpi_device_dir(device)) {
                ret = -ENODEV;
                goto remove_lid_dir;
        }

        /* create /proc/acpi/button/lid/LID/state */
        entry = proc_create_single_data(ACPI_BUTTON_FILE_STATE, S_IRUGO,
                        acpi_device_dir(device), acpi_button_state_seq_show,
                        button);
        if (!entry) {
                ret = -ENODEV;
                goto remove_dev_dir;
        }

done:
        return ret;

remove_dev_dir:
        remove_proc_entry(acpi_device_bid(device),
                          acpi_lid_dir);
        acpi_device_dir(device) = NULL;
remove_lid_dir:
        remove_proc_entry(ACPI_BUTTON_SUBCLASS_LID, acpi_button_dir);
        acpi_lid_dir = NULL;
remove_button_dir:
        remove_proc_entry(ACPI_BUTTON_CLASS, acpi_root_dir);
        acpi_button_dir = NULL;
        goto done;
}

static int acpi_button_remove_fs(struct acpi_button *button)
{
        struct acpi_device *device = button->adev;

        if (button->type != ACPI_BUTTON_TYPE_LID)
                return 0;

        remove_proc_entry(ACPI_BUTTON_FILE_STATE,
                          acpi_device_dir(device));
        remove_proc_entry(acpi_device_bid(device),
                          acpi_lid_dir);
        acpi_device_dir(device) = NULL;
        remove_proc_entry(ACPI_BUTTON_SUBCLASS_LID, acpi_button_dir);
        acpi_lid_dir = NULL;
        remove_proc_entry(ACPI_BUTTON_CLASS, acpi_root_dir);
        acpi_button_dir = NULL;

        return 0;
}

/* Driver Interface */
int acpi_lid_open(void)
{
        if (!lid_device)
                return -ENODEV;

        return acpi_lid_evaluate_state(lid_device);
}
EXPORT_SYMBOL(acpi_lid_open);

static int acpi_lid_update_state(struct acpi_button *button,
                                 bool signal_wakeup)
{
        struct acpi_device *device = button->adev;
        int state;

        state = acpi_lid_evaluate_state(device);
        if (state < 0)
                return state;

        if (state && signal_wakeup)
                acpi_pm_wakeup_event(button->dev);

        return acpi_lid_notify_state(button, state);
}

static void acpi_lid_initialize_state(struct acpi_button *button)
{
        switch (lid_init_state) {
        case ACPI_BUTTON_LID_INIT_OPEN:
                (void)acpi_lid_notify_state(button, 1);
                break;
        case ACPI_BUTTON_LID_INIT_METHOD:
                (void)acpi_lid_update_state(button, false);
                break;
        case ACPI_BUTTON_LID_INIT_IGNORE:
        default:
                break;
        }

        button->lid_state_initialized = true;
}

static void acpi_lid_notify(acpi_handle handle, u32 event, void *data)
{
        struct acpi_button *button = data;
        struct acpi_device *device = button->adev;

        if (event != ACPI_BUTTON_NOTIFY_STATUS) {
                acpi_handle_debug(device->handle, "Unsupported event [0x%x]\n",
                                  event);
                return;
        }

        if (!button->lid_state_initialized)
                return;

        acpi_lid_update_state(button, true);
}

static void acpi_button_notify(acpi_handle handle, u32 event, void *data)
{
        struct acpi_button *button = data;
        struct acpi_device *device = button->adev;
        struct input_dev *input;
        int keycode;

        switch (event) {
        case ACPI_BUTTON_NOTIFY_STATUS:
                break;
        case ACPI_BUTTON_NOTIFY_WAKE:
                break;
        default:
                acpi_handle_debug(device->handle, "Unsupported event [0x%x]\n",
                                  event);
                return;
        }

        acpi_pm_wakeup_event(button->dev);

        if (button->suspended || event == ACPI_BUTTON_NOTIFY_WAKE)
                return;

        input = button->input;
        keycode = test_bit(KEY_SLEEP, input->keybit) ? KEY_SLEEP : KEY_POWER;

        input_report_key(input, keycode, 1);
        input_sync(input);
        input_report_key(input, keycode, 0);
        input_sync(input);

        acpi_bus_generate_netlink_event(device->pnp.device_class,
                                        dev_name(&device->dev),
                                        event, ++button->pushed);
}

static void acpi_button_notify_run(void *data)
{
        acpi_button_notify(NULL, ACPI_BUTTON_NOTIFY_STATUS, data);
}

static u32 acpi_button_event(void *data)
{
        acpi_os_execute(OSL_NOTIFY_HANDLER, acpi_button_notify_run, data);
        return ACPI_INTERRUPT_HANDLED;
}

#ifdef CONFIG_PM_SLEEP
static int acpi_button_suspend(struct device *dev)
{
        struct acpi_button *button = dev_get_drvdata(dev);

        button->suspended = true;
        return 0;
}

static int acpi_button_resume(struct device *dev)
{
        struct acpi_button *button = dev_get_drvdata(dev);
        struct acpi_device *device = ACPI_COMPANION(dev);
        struct input_dev *input;

        button->suspended = false;
        if (button->type == ACPI_BUTTON_TYPE_LID) {
                button->last_state = !!acpi_lid_evaluate_state(device);
                button->last_time = ktime_get();
                acpi_lid_initialize_state(button);
        }

        if (button->type == ACPI_BUTTON_TYPE_POWER) {
                input = button->input;
                input_report_key(input, KEY_WAKEUP, 1);
                input_sync(input);
                input_report_key(input, KEY_WAKEUP, 0);
                input_sync(input);
        }
        return 0;
}
#endif

static int acpi_lid_input_open(struct input_dev *input)
{
        struct acpi_button *button = input_get_drvdata(input);
        struct acpi_device *device = button->adev;

        button->last_state = !!acpi_lid_evaluate_state(device);
        button->last_time = ktime_get();
        acpi_lid_initialize_state(button);

        return 0;
}

static int acpi_button_probe(struct platform_device *pdev)
{
        struct acpi_device *device = ACPI_COMPANION(&pdev->dev);
        acpi_notify_handler handler;
        struct acpi_button *button;
        struct input_dev *input;
        const char *hid = acpi_device_hid(device);
        acpi_status status;
        char *name, *class;
        int error = 0;

        if (!strcmp(hid, ACPI_BUTTON_HID_LID) &&
             lid_init_state == ACPI_BUTTON_LID_INIT_DISABLED)
                return -ENODEV;

        button = kzalloc_obj(struct acpi_button);
        if (!button)
                return -ENOMEM;

        platform_set_drvdata(pdev, button);

        button->dev = &pdev->dev;
        button->adev = device;
        button->input = input = input_allocate_device();
        if (!input) {
                error = -ENOMEM;
                goto err_free_button;
        }

        name = acpi_device_name(device);
        class = acpi_device_class(device);

        if (!strcmp(hid, ACPI_BUTTON_HID_POWER) ||
            !strcmp(hid, ACPI_BUTTON_HID_POWERF)) {
                button->type = ACPI_BUTTON_TYPE_POWER;
                handler = acpi_button_notify;
                strscpy(name, ACPI_BUTTON_DEVICE_NAME_POWER, MAX_ACPI_DEVICE_NAME_LEN);
                sprintf(class, "%s/%s",
                        ACPI_BUTTON_CLASS, ACPI_BUTTON_SUBCLASS_POWER);
        } else if (!strcmp(hid, ACPI_BUTTON_HID_SLEEP) ||
                   !strcmp(hid, ACPI_BUTTON_HID_SLEEPF)) {
                button->type = ACPI_BUTTON_TYPE_SLEEP;
                handler = acpi_button_notify;
                strscpy(name, ACPI_BUTTON_DEVICE_NAME_SLEEP, MAX_ACPI_DEVICE_NAME_LEN);
                sprintf(class, "%s/%s",
                        ACPI_BUTTON_CLASS, ACPI_BUTTON_SUBCLASS_SLEEP);
        } else if (!strcmp(hid, ACPI_BUTTON_HID_LID)) {
                button->type = ACPI_BUTTON_TYPE_LID;
                handler = acpi_lid_notify;
                strscpy(name, ACPI_BUTTON_DEVICE_NAME_LID, MAX_ACPI_DEVICE_NAME_LEN);
                sprintf(class, "%s/%s",
                        ACPI_BUTTON_CLASS, ACPI_BUTTON_SUBCLASS_LID);
                input->open = acpi_lid_input_open;
        } else {
                pr_info("Unsupported hid [%s]\n", hid);
                error = -ENODEV;
        }

        if (!error)
                error = acpi_button_add_fs(button);

        if (error) {
                input_free_device(input);
                goto err_free_button;
        }

        snprintf(button->phys, sizeof(button->phys), "%s/button/input0", hid);

        input->name = name;
        input->phys = button->phys;
        input->id.bustype = BUS_HOST;
        input->id.product = button->type;
        input->dev.parent = &pdev->dev;

        switch (button->type) {
        case ACPI_BUTTON_TYPE_POWER:
                input_set_capability(input, EV_KEY, KEY_POWER);
                input_set_capability(input, EV_KEY, KEY_WAKEUP);
                break;

        case ACPI_BUTTON_TYPE_SLEEP:
                input_set_capability(input, EV_KEY, KEY_SLEEP);
                break;

        case ACPI_BUTTON_TYPE_LID:
                input_set_capability(input, EV_SW, SW_LID);
                break;
        }

        input_set_drvdata(input, button);
        error = input_register_device(input);
        if (error) {
                input_free_device(input);
                goto err_remove_fs;
        }

        device_init_wakeup(button->dev, true);

        switch (device->device_type) {
        case ACPI_BUS_TYPE_POWER_BUTTON:
                status = acpi_install_fixed_event_handler(ACPI_EVENT_POWER_BUTTON,
                                                          acpi_button_event,
                                                          button);
                break;
        case ACPI_BUS_TYPE_SLEEP_BUTTON:
                status = acpi_install_fixed_event_handler(ACPI_EVENT_SLEEP_BUTTON,
                                                          acpi_button_event,
                                                          button);
                break;
        default:
                status = acpi_install_notify_handler(device->handle,
                                                     ACPI_ALL_NOTIFY, handler,
                                                     button);
                break;
        }
        if (ACPI_FAILURE(status)) {
                error = -ENODEV;
                goto err_input_unregister;
        }

        if (button->type == ACPI_BUTTON_TYPE_LID) {
                /*
                 * This assumes there's only one lid device, or if there are
                 * more we only care about the last one...
                 */
                lid_device = device;
        }

        pr_info("%s [%s]\n", name, acpi_device_bid(device));
        return 0;

err_input_unregister:
        device_init_wakeup(button->dev, false);
        input_unregister_device(input);
err_remove_fs:
        acpi_button_remove_fs(button);
err_free_button:
        kfree(button);
        return error;
}

static void acpi_button_remove(struct platform_device *pdev)
{
        struct acpi_button *button = platform_get_drvdata(pdev);
        struct acpi_device *adev = button->adev;

        switch (adev->device_type) {
        case ACPI_BUS_TYPE_POWER_BUTTON:
                acpi_remove_fixed_event_handler(ACPI_EVENT_POWER_BUTTON,
                                                acpi_button_event);
                break;
        case ACPI_BUS_TYPE_SLEEP_BUTTON:
                acpi_remove_fixed_event_handler(ACPI_EVENT_SLEEP_BUTTON,
                                                acpi_button_event);
                break;
        default:
                acpi_remove_notify_handler(adev->handle, ACPI_DEVICE_NOTIFY,
                                           button->type == ACPI_BUTTON_TYPE_LID ?
                                                acpi_lid_notify :
                                                acpi_button_notify);
                break;
        }
        acpi_os_wait_events_complete();

        device_init_wakeup(button->dev, false);

        acpi_button_remove_fs(button);
        input_unregister_device(button->input);
        kfree(button);
}

static int param_set_lid_init_state(const char *val,
                                    const struct kernel_param *kp)
{
        int i;

        i = sysfs_match_string(lid_init_state_str, val);
        if (i < 0)
                return i;

        lid_init_state = i;
        pr_info("Initial lid state set to '%s'\n", lid_init_state_str[i]);
        return 0;
}

static int param_get_lid_init_state(char *buf, const struct kernel_param *kp)
{
        int i, c = 0;

        for (i = 0; i < ARRAY_SIZE(lid_init_state_str); i++)
                if (i == lid_init_state)
                        c += sprintf(buf + c, "[%s] ", lid_init_state_str[i]);
                else
                        c += sprintf(buf + c, "%s ", lid_init_state_str[i]);

        buf[c - 1] = '\n'; /* Replace the final space with a newline */

        return c;
}

module_param_call(lid_init_state,
                  param_set_lid_init_state, param_get_lid_init_state,
                  NULL, 0644);
MODULE_PARM_DESC(lid_init_state, "Behavior for reporting LID initial state");

static int __init acpi_button_init(void)
{
        const struct dmi_system_id *dmi_id;

        if (lid_init_state == -1) {
                dmi_id = dmi_first_match(dmi_lid_quirks);
                if (dmi_id)
                        lid_init_state = (long)dmi_id->driver_data;
                else
                        lid_init_state = ACPI_BUTTON_LID_INIT_METHOD;
        }

        /*
         * Modules such as nouveau.ko and i915.ko have a link time dependency
         * on acpi_lid_open(), and would therefore not be loadable on ACPI
         * capable kernels booted in non-ACPI mode if the return value of
         * platform_driver_register() is returned from here with ACPI disabled
         * when this driver is built as a module.
         */
        if (acpi_disabled)
                return 0;

        return platform_driver_register(&acpi_button_driver);
}

static void __exit acpi_button_exit(void)
{
        if (!acpi_disabled)
                platform_driver_unregister(&acpi_button_driver);
}

module_init(acpi_button_init);
module_exit(acpi_button_exit);