/*
 * HID over I2C ACPI Subclass
 *
 * Copyright (c) 2012 Benjamin Tissoires <benjamin.tissoires@gmail.com>
 * Copyright (c) 2012 Ecole Nationale de l'Aviation Civile, France
 * Copyright (c) 2012 Red Hat, Inc
 *
 * This code was forked out of the core code, which was partly based on
 * "USB HID support for Linux":
 *
 *  Copyright (c) 1999 Andreas Gal
 *  Copyright (c) 2000-2005 Vojtech Pavlik <vojtech@suse.cz>
 *  Copyright (c) 2005 Michael Haboustak <mike-@cinci.rr.com> for Concept2, Inc
 *  Copyright (c) 2007-2008 Oliver Neukum
 *  Copyright (c) 2006-2010 Jiri Kosina
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file COPYING in the main directory of this archive for
 * more details.
 */

#include <linux/acpi.h>
#include <linux/device.h>
#include <linux/i2c.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/pm.h>
#include <linux/uuid.h>

#include "i2c-hid.h"

struct i2c_hid_acpi {
        struct i2chid_ops ops;
        struct acpi_device *adev;
};

static const struct acpi_device_id i2c_hid_acpi_blacklist[] = {
        /*
         * The CHPN0001 ACPI device, which is used to describe the Chipone
         * ICN8505 controller, has a _CID of PNP0C50 but is not HID compatible.
         */
        { "CHPN0001" },
        /*
         * The IDEA5002 ACPI device causes high interrupt usage and spurious
         * wakeups from suspend.
         */
        { "IDEA5002" },
        { }
};

/* HID I²C Device: 3cdff6f7-4267-4555-ad05-b30a3d8938de */
static guid_t i2c_hid_guid =
        GUID_INIT(0x3CDFF6F7, 0x4267, 0x4555,
                  0xAD, 0x05, 0xB3, 0x0A, 0x3D, 0x89, 0x38, 0xDE);

static int i2c_hid_acpi_get_descriptor(struct i2c_hid_acpi *ihid_acpi)
{
        struct acpi_device *adev = ihid_acpi->adev;
        acpi_handle handle = acpi_device_handle(adev);
        union acpi_object *obj;
        u16 hid_descriptor_address;

        if (acpi_match_device_ids(adev, i2c_hid_acpi_blacklist) == 0)
                return -ENODEV;

        obj = acpi_evaluate_dsm_typed(handle, &i2c_hid_guid, 1, 1, NULL,
                                      ACPI_TYPE_INTEGER);
        if (!obj) {
                acpi_handle_err(handle, "Error _DSM call to get HID descriptor address failed\n");
                return -ENODEV;
        }

        hid_descriptor_address = obj->integer.value;
        ACPI_FREE(obj);

        return hid_descriptor_address;
}

static void i2c_hid_acpi_restore_sequence(struct i2chid_ops *ops)
{
        struct i2c_hid_acpi *ihid_acpi = container_of(ops, struct i2c_hid_acpi, ops);

        i2c_hid_acpi_get_descriptor(ihid_acpi);
}

static void i2c_hid_acpi_shutdown_tail(struct i2chid_ops *ops)
{
        struct i2c_hid_acpi *ihid_acpi = container_of(ops, struct i2c_hid_acpi, ops);

        acpi_device_set_power(ihid_acpi->adev, ACPI_STATE_D3_COLD);
}

static int i2c_hid_acpi_probe(struct i2c_client *client)
{
        struct device *dev = &client->dev;
        struct i2c_hid_acpi *ihid_acpi;
        u16 hid_descriptor_address;
        int ret;

        ihid_acpi = devm_kzalloc(&client->dev, sizeof(*ihid_acpi), GFP_KERNEL);
        if (!ihid_acpi)
                return -ENOMEM;

        ihid_acpi->adev = ACPI_COMPANION(dev);
        ihid_acpi->ops.shutdown_tail = i2c_hid_acpi_shutdown_tail;
        ihid_acpi->ops.restore_sequence = i2c_hid_acpi_restore_sequence;

        ret = i2c_hid_acpi_get_descriptor(ihid_acpi);
        if (ret < 0)
                return ret;
        hid_descriptor_address = ret;

        acpi_device_fix_up_power(ihid_acpi->adev);

        return i2c_hid_core_probe(client, &ihid_acpi->ops,
                                  hid_descriptor_address, 0);
}

static const struct acpi_device_id i2c_hid_acpi_match[] = {
        { "ACPI0C50" },
        { "PNP0C50" },
        { }
};
MODULE_DEVICE_TABLE(acpi, i2c_hid_acpi_match);

static struct i2c_driver i2c_hid_acpi_driver = {
        .driver = {
                .name   = "i2c_hid_acpi",
                .pm     = &i2c_hid_core_pm,
                .probe_type = PROBE_PREFER_ASYNCHRONOUS,
                .acpi_match_table = i2c_hid_acpi_match,
        },

        .probe          = i2c_hid_acpi_probe,
        .remove         = i2c_hid_core_remove,
        .shutdown       = i2c_hid_core_shutdown,
};

module_i2c_driver(i2c_hid_acpi_driver);

MODULE_DESCRIPTION("HID over I2C ACPI driver");
MODULE_AUTHOR("Benjamin Tissoires <benjamin.tissoires@gmail.com>");
MODULE_LICENSE("GPL");