// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  OLPC XO-1.5 ebook switch driver
 *  (based on generic ACPI button driver)
 *
 *  Copyright (C) 2009 Paul Fox <pgf@laptop.org>
 *  Copyright (C) 2010 One Laptop per Child
 */

#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/acpi.h>
#include <linux/platform_device.h>

#define MODULE_NAME "xo15-ebook"

#define XO15_EBOOK_CLASS                MODULE_NAME
#define XO15_EBOOK_TYPE_UNKNOWN 0x00
#define XO15_EBOOK_NOTIFY_STATUS        0x80

#define XO15_EBOOK_SUBCLASS             "ebook"
#define XO15_EBOOK_HID                  "XO15EBK"
#define XO15_EBOOK_DEVICE_NAME          "EBook Switch"

MODULE_DESCRIPTION("OLPC XO-1.5 ebook switch driver");
MODULE_LICENSE("GPL");

static const struct acpi_device_id ebook_device_ids[] = {
        { XO15_EBOOK_HID, 0 },
        { "", 0 },
};
MODULE_DEVICE_TABLE(acpi, ebook_device_ids);

struct ebook_switch {
        struct input_dev *input;
        char phys[32];                  /* for input device */
        bool gpe_enabled;
};

static int ebook_send_state(struct device *dev)
{
        struct ebook_switch *button = dev_get_drvdata(dev);
        unsigned long long state;
        acpi_status status;

        status = acpi_evaluate_integer(ACPI_HANDLE(dev), "EBK", NULL, &state);
        if (ACPI_FAILURE(status))
                return -EIO;

        /* input layer checks if event is redundant */
        input_report_switch(button->input, SW_TABLET_MODE, !state);
        input_sync(button->input);
        return 0;
}

static void ebook_switch_notify(acpi_handle handle, u32 event, void *data)
{
        switch (event) {
        case ACPI_FIXED_HARDWARE_EVENT:
        case XO15_EBOOK_NOTIFY_STATUS:
                ebook_send_state(data);
                break;
        default:
                acpi_handle_debug(handle, "Unsupported event [0x%x]\n", event);
                break;
        }
}

#ifdef CONFIG_PM_SLEEP
static int ebook_switch_resume(struct device *dev)
{
        return ebook_send_state(dev);
}
#endif

static SIMPLE_DEV_PM_OPS(ebook_switch_pm, NULL, ebook_switch_resume);

static int ebook_switch_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct acpi_device *device = ACPI_COMPANION(dev);
        const struct acpi_device_id *id;
        struct ebook_switch *button;
        struct input_dev *input;
        int error;

        button = devm_kzalloc(dev, sizeof(*button), GFP_KERNEL);
        if (!button)
                return -ENOMEM;

        platform_set_drvdata(pdev, button);

        input = devm_input_allocate_device(dev);
        if (!input)
                return -ENOMEM;

        button->input = input;

        id = acpi_match_acpi_device(ebook_device_ids, device);
        if (!id)
                return dev_err_probe(dev, -ENODEV, "Unsupported hid\n");

        strscpy(acpi_device_name(device), XO15_EBOOK_DEVICE_NAME);
        strscpy(acpi_device_class(device), XO15_EBOOK_CLASS "/" XO15_EBOOK_SUBCLASS);

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

        input->name = acpi_device_name(device);
        input->phys = button->phys;
        input->id.bustype = BUS_HOST;

        input->evbit[0] = BIT_MASK(EV_SW);
        set_bit(SW_TABLET_MODE, input->swbit);

        error = input_register_device(input);
        if (error)
                return error;

        error = acpi_dev_install_notify_handler(device, ACPI_DEVICE_NOTIFY,
                                                ebook_switch_notify, dev);
        if (error)
                return error;

        ebook_send_state(dev);

        if (device->wakeup.flags.valid) {
                /* Button's GPE is run-wake GPE */
                acpi_enable_gpe(device->wakeup.gpe_device,
                                device->wakeup.gpe_number);
                button->gpe_enabled = true;
        }

        return 0;
}

static void ebook_switch_remove(struct platform_device *pdev)
{
        struct ebook_switch *button = platform_get_drvdata(pdev);
        struct acpi_device *device = ACPI_COMPANION(&pdev->dev);

        if (button->gpe_enabled)
                acpi_disable_gpe(device->wakeup.gpe_device,
                                 device->wakeup.gpe_number);

        acpi_dev_remove_notify_handler(device, ACPI_DEVICE_NOTIFY,
                                       ebook_switch_notify);
}

static struct platform_driver xo15_ebook_driver = {
        .probe = ebook_switch_probe,
        .remove = ebook_switch_remove,
        .driver = {
                .name = MODULE_NAME,
                .acpi_match_table = ebook_device_ids,
                .pm = &ebook_switch_pm,
        },
};
module_platform_driver(xo15_ebook_driver);