/*
 *  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>
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 *  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.
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 */

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

#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 <acpi/button.h>

#define PREFIX "ACPI: "

#define ACPI_BUTTON_CLASS               "button"
#define ACPI_BUTTON_FILE_INFO           "info"
#define ACPI_BUTTON_FILE_STATE          "state"
#define ACPI_BUTTON_TYPE_UNKNOWN        0x00
#define ACPI_BUTTON_NOTIFY_STATUS       0x80

#define ACPI_BUTTON_SUBCLASS_POWER      "power"
#define ACPI_BUTTON_HID_POWER           "PNP0C0C"
#define ACPI_BUTTON_DEVICE_NAME_POWER   "Power Button"
#define ACPI_BUTTON_TYPE_POWER          0x01

#define ACPI_BUTTON_SUBCLASS_SLEEP      "sleep"
#define ACPI_BUTTON_HID_SLEEP           "PNP0C0E"
#define ACPI_BUTTON_DEVICE_NAME_SLEEP   "Sleep Button"
#define ACPI_BUTTON_TYPE_SLEEP          0x03

#define ACPI_BUTTON_SUBCLASS_LID        "lid"
#define ACPI_BUTTON_HID_LID             "PNP0C0D"
#define ACPI_BUTTON_DEVICE_NAME_LID     "Lid Switch"
#define ACPI_BUTTON_TYPE_LID            0x05

#define ACPI_BUTTON_LID_INIT_IGNORE     0x00
#define ACPI_BUTTON_LID_INIT_OPEN       0x01
#define ACPI_BUTTON_LID_INIT_METHOD     0x02

#define _COMPONENT              ACPI_BUTTON_COMPONENT
ACPI_MODULE_NAME("button");

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);

static int acpi_button_add(struct acpi_device *device);
static int acpi_button_remove(struct acpi_device *device);
static void acpi_button_notify(struct acpi_device *device, u32 event);

#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 acpi_driver acpi_button_driver = {
        .name = "button",
        .class = ACPI_BUTTON_CLASS,
        .ids = button_device_ids,
        .ops = {
                .add = acpi_button_add,
                .remove = acpi_button_remove,
                .notify = acpi_button_notify,
        },
        .drv.pm = &acpi_button_pm,
};

struct acpi_button {
        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;
};

static BLOCKING_NOTIFIER_HEAD(acpi_lid_notifier);
static struct acpi_device *lid_device;
static u8 lid_init_state = ACPI_BUTTON_LID_INIT_METHOD;

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_device *device, int state)
{
        struct acpi_button *button = acpi_driver_data(device);
        int ret;
        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) {
                input_report_switch(button->input, SW_LID, !state);
                input_sync(button->input);
                button->last_state = !!state;
                button->last_time = ktime_get();
        }

        if (state)
                acpi_pm_wakeup_event(&device->dev);

        ret = blocking_notifier_call_chain(&acpi_lid_notifier, state, device);
        if (ret == NOTIFY_DONE)
                ret = blocking_notifier_call_chain(&acpi_lid_notifier, state,
                                                   device);
        if (ret == NOTIFY_DONE || ret == NOTIFY_OK) {
                /*
                 * It is also regarded as success if the notifier_chain
                 * returns NOTIFY_OK or NOTIFY_DONE.
                 */
                ret = 0;
        }
        return ret;
}

static int acpi_button_state_seq_show(struct seq_file *seq, void *offset)
{
        struct acpi_device *device = seq->private;
        int state;

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

static int acpi_button_state_open_fs(struct inode *inode, struct file *file)
{
        return single_open(file, acpi_button_state_seq_show, PDE_DATA(inode));
}

static const struct file_operations acpi_button_state_fops = {
        .owner = THIS_MODULE,
        .open = acpi_button_state_open_fs,
        .read = seq_read,
        .llseek = seq_lseek,
        .release = single_release,
};

static int acpi_button_add_fs(struct acpi_device *device)
{
        struct acpi_button *button = acpi_driver_data(device);
        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) {
                printk(KERN_ERR PREFIX "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_data(ACPI_BUTTON_FILE_STATE,
                                 S_IRUGO, acpi_device_dir(device),
                                 &acpi_button_state_fops, device);
        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_device *device)
{
        struct acpi_button *button = acpi_driver_data(device);

        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_notifier_register(struct notifier_block *nb)
{
        return blocking_notifier_chain_register(&acpi_lid_notifier, nb);
}
EXPORT_SYMBOL(acpi_lid_notifier_register);

int acpi_lid_notifier_unregister(struct notifier_block *nb)
{
        return blocking_notifier_chain_unregister(&acpi_lid_notifier, nb);
}
EXPORT_SYMBOL(acpi_lid_notifier_unregister);

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_device *device)
{
        int state;

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

        return acpi_lid_notify_state(device, state);
}

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

static void acpi_button_notify(struct acpi_device *device, u32 event)
{
        struct acpi_button *button = acpi_driver_data(device);
        struct input_dev *input;

        switch (event) {
        case ACPI_FIXED_HARDWARE_EVENT:
                event = ACPI_BUTTON_NOTIFY_STATUS;
                /* fall through */
        case ACPI_BUTTON_NOTIFY_STATUS:
                input = button->input;
                if (button->type == ACPI_BUTTON_TYPE_LID) {
                        acpi_lid_update_state(device);
                } else {
                        int keycode;

                        acpi_pm_wakeup_event(&device->dev);
                        if (button->suspended)
                                break;

                        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);
                }
                break;
        default:
                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                                  "Unsupported event [0x%x]\n", event));
                break;
        }
}

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

        button->suspended = true;
        return 0;
}

static int acpi_button_resume(struct device *dev)
{
        struct acpi_device *device = to_acpi_device(dev);
        struct acpi_button *button = acpi_driver_data(device);

        button->suspended = false;
        if (button->type == ACPI_BUTTON_TYPE_LID)
                acpi_lid_initialize_state(device);
        return 0;
}
#endif

static int acpi_button_add(struct acpi_device *device)
{
        struct acpi_button *button;
        struct input_dev *input;
        const char *hid = acpi_device_hid(device);
        char *name, *class;
        int error;

        button = kzalloc(sizeof(struct acpi_button), GFP_KERNEL);
        if (!button)
                return -ENOMEM;

        device->driver_data = button;

        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;
                strcpy(name, ACPI_BUTTON_DEVICE_NAME_POWER);
                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;
                strcpy(name, ACPI_BUTTON_DEVICE_NAME_SLEEP);
                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;
                strcpy(name, ACPI_BUTTON_DEVICE_NAME_LID);
                sprintf(class, "%s/%s",
                        ACPI_BUTTON_CLASS, ACPI_BUTTON_SUBCLASS_LID);
                button->last_state = !!acpi_lid_evaluate_state(device);
                button->last_time = ktime_get();
        } else {
                printk(KERN_ERR PREFIX "Unsupported hid [%s]\n", hid);
                error = -ENODEV;
                goto err_free_input;
        }

        error = acpi_button_add_fs(device);
        if (error)
                goto err_free_input;

        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 = &device->dev;

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

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

        device_init_wakeup(&device->dev, true);
        printk(KERN_INFO PREFIX "%s [%s]\n", name, acpi_device_bid(device));
        return 0;

 err_remove_fs:
        acpi_button_remove_fs(device);
 err_free_input:
        input_free_device(input);
 err_free_button:
        kfree(button);
        return error;
}

static int acpi_button_remove(struct acpi_device *device)
{
        struct acpi_button *button = acpi_driver_data(device);

        acpi_button_remove_fs(device);
        input_unregister_device(button->input);
        kfree(button);
        return 0;
}

static int param_set_lid_init_state(const char *val, struct kernel_param *kp)
{
        int result = 0;

        if (!strncmp(val, "open", sizeof("open") - 1)) {
                lid_init_state = ACPI_BUTTON_LID_INIT_OPEN;
                pr_info("Notify initial lid state as open\n");
        } else if (!strncmp(val, "method", sizeof("method") - 1)) {
                lid_init_state = ACPI_BUTTON_LID_INIT_METHOD;
                pr_info("Notify initial lid state with _LID return value\n");
        } else if (!strncmp(val, "ignore", sizeof("ignore") - 1)) {
                lid_init_state = ACPI_BUTTON_LID_INIT_IGNORE;
                pr_info("Do not notify initial lid state\n");
        } else
                result = -EINVAL;
        return result;
}

static int param_get_lid_init_state(char *buffer, struct kernel_param *kp)
{
        switch (lid_init_state) {
        case ACPI_BUTTON_LID_INIT_OPEN:
                return sprintf(buffer, "open");
        case ACPI_BUTTON_LID_INIT_METHOD:
                return sprintf(buffer, "method");
        case ACPI_BUTTON_LID_INIT_IGNORE:
                return sprintf(buffer, "ignore");
        default:
                return sprintf(buffer, "invalid");
        }
        return 0;
}

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");

module_acpi_driver(acpi_button_driver);