// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  Airplane mode button for AMD, HP & Xiaomi laptops
 *
 *  Copyright (C) 2014-2017 Alex Hung <alex.hung@canonical.com>
 *  Copyright (C) 2021 Advanced Micro Devices
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/input.h>
#include <linux/platform_device.h>
#include <linux/acpi.h>
#include <acpi/acpi_bus.h>

MODULE_DESCRIPTION("Airplane mode button for AMD, HP & Xiaomi laptops");
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Alex Hung");
MODULE_ALIAS("acpi*:HPQ6001:*");
MODULE_ALIAS("acpi*:WSTADEF:*");
MODULE_ALIAS("acpi*:AMDI0051:*");
MODULE_ALIAS("acpi*:LGEX0815:*");

struct wl_button {
        struct input_dev *input_dev;
        char phys[32];
};

static const struct acpi_device_id wl_ids[] = {
        {"HPQ6001", 0},
        {"WSTADEF", 0},
        {"AMDI0051", 0},
        {"LGEX0815", 0},
        {"", 0},
};

static int wireless_input_setup(struct acpi_device *device)
{
        struct wl_button *button = acpi_driver_data(device);
        int err;

        button->input_dev = input_allocate_device();
        if (!button->input_dev)
                return -ENOMEM;

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

        button->input_dev->name = "Wireless hotkeys";
        button->input_dev->phys = button->phys;
        button->input_dev->id.bustype = BUS_HOST;
        button->input_dev->evbit[0] = BIT(EV_KEY);
        set_bit(KEY_RFKILL, button->input_dev->keybit);

        err = input_register_device(button->input_dev);
        if (err)
                goto err_free_dev;

        return 0;

err_free_dev:
        input_free_device(button->input_dev);
        return err;
}

static void wireless_input_destroy(struct acpi_device *device)
{
        struct wl_button *button = acpi_driver_data(device);

        input_unregister_device(button->input_dev);
        kfree(button);
}

static void wl_notify(struct acpi_device *acpi_dev, u32 event)
{
        struct wl_button *button = acpi_driver_data(acpi_dev);

        if (event != 0x80) {
                pr_info("Received unknown event (0x%x)\n", event);
                return;
        }

        input_report_key(button->input_dev, KEY_RFKILL, 1);
        input_sync(button->input_dev);
        input_report_key(button->input_dev, KEY_RFKILL, 0);
        input_sync(button->input_dev);
}

static int wl_add(struct acpi_device *device)
{
        struct wl_button *button;
        int err;

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

        device->driver_data = button;

        err = wireless_input_setup(device);
        if (err) {
                pr_err("Failed to setup wireless hotkeys\n");
                kfree(button);
        }

        return err;
}

static void wl_remove(struct acpi_device *device)
{
        wireless_input_destroy(device);
}

static struct acpi_driver wl_driver = {
        .name   = "wireless-hotkey",
        .ids    = wl_ids,
        .ops    = {
                .add    = wl_add,
                .remove = wl_remove,
                .notify = wl_notify,
        },
};

module_acpi_driver(wl_driver);