// SPDX-License-Identifier: GPL-2.0+
/*
 *  Intel HID event & 5 button array driver
 *
 *  Copyright (C) 2015 Alex Hung <alex.hung@canonical.com>
 *  Copyright (C) 2015 Andrew Lutomirski <luto@kernel.org>
 */

#include <linux/acpi.h>
#include <linux/dmi.h>
#include <linux/input.h>
#include <linux/input/sparse-keymap.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/suspend.h>

/* When NOT in tablet mode, VGBS returns with the flag 0x40 */
#define TABLET_MODE_FLAG BIT(6)

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Alex Hung");

static const struct acpi_device_id intel_hid_ids[] = {
        {"INT33D5", 0},
        {"INTC1051", 0},
        {"INTC1054", 0},
        {"", 0},
};
MODULE_DEVICE_TABLE(acpi, intel_hid_ids);

/* In theory, these are HID usages. */
static const struct key_entry intel_hid_keymap[] = {
        /* 1: LSuper (Page 0x07, usage 0xE3) -- unclear what to do */
        /* 2: Toggle SW_ROTATE_LOCK -- easy to implement if seen in wild */
        { KE_KEY, 3, { KEY_NUMLOCK } },
        { KE_KEY, 4, { KEY_HOME } },
        { KE_KEY, 5, { KEY_END } },
        { KE_KEY, 6, { KEY_PAGEUP } },
        { KE_KEY, 7, { KEY_PAGEDOWN } },
        { KE_KEY, 8, { KEY_RFKILL } },
        { KE_KEY, 9, { KEY_POWER } },
        { KE_KEY, 11, { KEY_SLEEP } },
        /* 13 has two different meanings in the spec -- ignore it. */
        { KE_KEY, 14, { KEY_STOPCD } },
        { KE_KEY, 15, { KEY_PLAYPAUSE } },
        { KE_KEY, 16, { KEY_MUTE } },
        { KE_KEY, 17, { KEY_VOLUMEUP } },
        { KE_KEY, 18, { KEY_VOLUMEDOWN } },
        { KE_KEY, 19, { KEY_BRIGHTNESSUP } },
        { KE_KEY, 20, { KEY_BRIGHTNESSDOWN } },
        /* 27: wake -- needs special handling */
        { KE_END },
};

/* 5 button array notification value. */
static const struct key_entry intel_array_keymap[] = {
        { KE_KEY,    0xC2, { KEY_LEFTMETA } },                /* Press */
        { KE_IGNORE, 0xC3, { KEY_LEFTMETA } },                /* Release */
        { KE_KEY,    0xC4, { KEY_VOLUMEUP } },                /* Press */
        { KE_IGNORE, 0xC5, { KEY_VOLUMEUP } },                /* Release */
        { KE_KEY,    0xC6, { KEY_VOLUMEDOWN } },              /* Press */
        { KE_IGNORE, 0xC7, { KEY_VOLUMEDOWN } },              /* Release */
        { KE_KEY,    0xC8, { KEY_ROTATE_LOCK_TOGGLE } },      /* Press */
        { KE_IGNORE, 0xC9, { KEY_ROTATE_LOCK_TOGGLE } },      /* Release */
        { KE_KEY,    0xCE, { KEY_POWER } },                   /* Press */
        { KE_IGNORE, 0xCF, { KEY_POWER } },                   /* Release */
        { KE_END },
};

static const struct dmi_system_id button_array_table[] = {
        {
                .ident = "Wacom MobileStudio Pro 13",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Wacom Co.,Ltd"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "Wacom MobileStudio Pro 13"),
                },
        },
        {
                .ident = "Wacom MobileStudio Pro 16",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Wacom Co.,Ltd"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "Wacom MobileStudio Pro 16"),
                },
        },
        {
                .ident = "HP Spectre x2 (2015)",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "HP"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "HP Spectre x2 Detachable"),
                },
        },
        { }
};

/*
 * Some convertible use the intel-hid ACPI interface to report SW_TABLET_MODE,
 * these need to be compared via a DMI based authorization list because some
 * models have unreliable VGBS return which could cause incorrect
 * SW_TABLET_MODE report.
 */
static const struct dmi_system_id dmi_vgbs_allow_list[] = {
        {
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "HP"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "HP Spectre x360 Convertible 15-df0xxx"),
                },
        },
        { }
};

struct intel_hid_priv {
        struct input_dev *input_dev;
        struct input_dev *array;
        struct input_dev *switches;
        bool wakeup_mode;
};

#define HID_EVENT_FILTER_UUID   "eeec56b3-4442-408f-a792-4edd4d758054"

enum intel_hid_dsm_fn_codes {
        INTEL_HID_DSM_FN_INVALID,
        INTEL_HID_DSM_BTNL_FN,
        INTEL_HID_DSM_HDMM_FN,
        INTEL_HID_DSM_HDSM_FN,
        INTEL_HID_DSM_HDEM_FN,
        INTEL_HID_DSM_BTNS_FN,
        INTEL_HID_DSM_BTNE_FN,
        INTEL_HID_DSM_HEBC_V1_FN,
        INTEL_HID_DSM_VGBS_FN,
        INTEL_HID_DSM_HEBC_V2_FN,
        INTEL_HID_DSM_FN_MAX
};

static const char *intel_hid_dsm_fn_to_method[INTEL_HID_DSM_FN_MAX] = {
        NULL,
        "BTNL",
        "HDMM",
        "HDSM",
        "HDEM",
        "BTNS",
        "BTNE",
        "HEBC",
        "VGBS",
        "HEBC"
};

static unsigned long long intel_hid_dsm_fn_mask;
static guid_t intel_dsm_guid;

static bool intel_hid_execute_method(acpi_handle handle,
                                     enum intel_hid_dsm_fn_codes fn_index,
                                     unsigned long long arg)
{
        union acpi_object *obj, argv4, req;
        acpi_status status;
        char *method_name;

        if (fn_index <= INTEL_HID_DSM_FN_INVALID ||
            fn_index >= INTEL_HID_DSM_FN_MAX)
                return false;

        method_name = (char *)intel_hid_dsm_fn_to_method[fn_index];

        if (!(intel_hid_dsm_fn_mask & BIT(fn_index)))
                goto skip_dsm_exec;

        /* All methods expects a package with one integer element */
        req.type = ACPI_TYPE_INTEGER;
        req.integer.value = arg;

        argv4.type = ACPI_TYPE_PACKAGE;
        argv4.package.count = 1;
        argv4.package.elements = &req;

        obj = acpi_evaluate_dsm(handle, &intel_dsm_guid, 1, fn_index, &argv4);
        if (obj) {
                acpi_handle_debug(handle, "Exec DSM Fn code: %d[%s] success\n",
                                  fn_index, method_name);
                ACPI_FREE(obj);
                return true;
        }

skip_dsm_exec:
        status = acpi_execute_simple_method(handle, method_name, arg);
        if (ACPI_SUCCESS(status))
                return true;

        return false;
}

static bool intel_hid_evaluate_method(acpi_handle handle,
                                      enum intel_hid_dsm_fn_codes fn_index,
                                      unsigned long long *result)
{
        union acpi_object *obj;
        acpi_status status;
        char *method_name;

        if (fn_index <= INTEL_HID_DSM_FN_INVALID ||
            fn_index >= INTEL_HID_DSM_FN_MAX)
                return false;

        method_name = (char *)intel_hid_dsm_fn_to_method[fn_index];

        if (!(intel_hid_dsm_fn_mask & fn_index))
                goto skip_dsm_eval;

        obj = acpi_evaluate_dsm_typed(handle, &intel_dsm_guid,
                                      1, fn_index,
                                      NULL,  ACPI_TYPE_INTEGER);
        if (obj) {
                *result = obj->integer.value;
                acpi_handle_debug(handle,
                                  "Eval DSM Fn code: %d[%s] results: 0x%llx\n",
                                  fn_index, method_name, *result);
                ACPI_FREE(obj);
                return true;
        }

skip_dsm_eval:
        status = acpi_evaluate_integer(handle, method_name, NULL, result);
        if (ACPI_SUCCESS(status))
                return true;

        return false;
}

static void intel_hid_init_dsm(acpi_handle handle)
{
        union acpi_object *obj;

        guid_parse(HID_EVENT_FILTER_UUID, &intel_dsm_guid);

        obj = acpi_evaluate_dsm_typed(handle, &intel_dsm_guid, 1, 0, NULL,
                                      ACPI_TYPE_BUFFER);
        if (obj) {
                switch (obj->buffer.length) {
                default:
                case 2:
                        intel_hid_dsm_fn_mask = *(u16 *)obj->buffer.pointer;
                        break;
                case 1:
                        intel_hid_dsm_fn_mask = *obj->buffer.pointer;
                        break;
                case 0:
                        acpi_handle_warn(handle, "intel_hid_dsm_fn_mask length is zero\n");
                        intel_hid_dsm_fn_mask = 0;
                        break;
                }
                ACPI_FREE(obj);
        }

        acpi_handle_debug(handle, "intel_hid_dsm_fn_mask = %llx\n",
                          intel_hid_dsm_fn_mask);
}

static int intel_hid_set_enable(struct device *device, bool enable)
{
        acpi_handle handle = ACPI_HANDLE(device);

        /* Enable|disable features - power button is always enabled */
        if (!intel_hid_execute_method(handle, INTEL_HID_DSM_HDSM_FN,
                                      enable)) {
                dev_warn(device, "failed to %sable hotkeys\n",
                         enable ? "en" : "dis");
                return -EIO;
        }

        return 0;
}

static void intel_button_array_enable(struct device *device, bool enable)
{
        struct intel_hid_priv *priv = dev_get_drvdata(device);
        acpi_handle handle = ACPI_HANDLE(device);
        unsigned long long button_cap;
        acpi_status status;

        if (!priv->array)
                return;

        /* Query supported platform features */
        status = acpi_evaluate_integer(handle, "BTNC", NULL, &button_cap);
        if (ACPI_FAILURE(status)) {
                dev_warn(device, "failed to get button capability\n");
                return;
        }

        /* Enable|disable features - power button is always enabled */
        if (!intel_hid_execute_method(handle, INTEL_HID_DSM_BTNE_FN,
                                      enable ? button_cap : 1))
                dev_warn(device, "failed to set button capability\n");
}

static int intel_hid_pm_prepare(struct device *device)
{
        if (device_may_wakeup(device)) {
                struct intel_hid_priv *priv = dev_get_drvdata(device);

                priv->wakeup_mode = true;
        }
        return 0;
}

static void intel_hid_pm_complete(struct device *device)
{
        struct intel_hid_priv *priv = dev_get_drvdata(device);

        priv->wakeup_mode = false;
}

static int intel_hid_pl_suspend_handler(struct device *device)
{
        intel_button_array_enable(device, false);

        if (!pm_suspend_no_platform())
                intel_hid_set_enable(device, false);

        return 0;
}

static int intel_hid_pl_resume_handler(struct device *device)
{
        intel_hid_pm_complete(device);

        if (!pm_suspend_no_platform())
                intel_hid_set_enable(device, true);

        intel_button_array_enable(device, true);
        return 0;
}

static const struct dev_pm_ops intel_hid_pl_pm_ops = {
        .prepare = intel_hid_pm_prepare,
        .complete = intel_hid_pm_complete,
        .freeze  = intel_hid_pl_suspend_handler,
        .thaw  = intel_hid_pl_resume_handler,
        .restore  = intel_hid_pl_resume_handler,
        .suspend  = intel_hid_pl_suspend_handler,
        .resume  = intel_hid_pl_resume_handler,
};

static int intel_hid_input_setup(struct platform_device *device)
{
        struct intel_hid_priv *priv = dev_get_drvdata(&device->dev);
        int ret;

        priv->input_dev = devm_input_allocate_device(&device->dev);
        if (!priv->input_dev)
                return -ENOMEM;

        ret = sparse_keymap_setup(priv->input_dev, intel_hid_keymap, NULL);
        if (ret)
                return ret;

        priv->input_dev->name = "Intel HID events";
        priv->input_dev->id.bustype = BUS_HOST;

        return input_register_device(priv->input_dev);
}

static int intel_button_array_input_setup(struct platform_device *device)
{
        struct intel_hid_priv *priv = dev_get_drvdata(&device->dev);
        int ret;

        /* Setup input device for 5 button array */
        priv->array = devm_input_allocate_device(&device->dev);
        if (!priv->array)
                return -ENOMEM;

        ret = sparse_keymap_setup(priv->array, intel_array_keymap, NULL);
        if (ret)
                return ret;

        priv->array->name = "Intel HID 5 button array";
        priv->array->id.bustype = BUS_HOST;

        return input_register_device(priv->array);
}

static int intel_hid_switches_setup(struct platform_device *device)
{
        struct intel_hid_priv *priv = dev_get_drvdata(&device->dev);

        /* Setup input device for switches */
        priv->switches = devm_input_allocate_device(&device->dev);
        if (!priv->switches)
                return -ENOMEM;

        __set_bit(EV_SW, priv->switches->evbit);
        __set_bit(SW_TABLET_MODE, priv->switches->swbit);

        priv->switches->name = "Intel HID switches";
        priv->switches->id.bustype = BUS_HOST;
        return input_register_device(priv->switches);
}

static void report_tablet_mode_state(struct platform_device *device)
{
        struct intel_hid_priv *priv = dev_get_drvdata(&device->dev);
        acpi_handle handle = ACPI_HANDLE(&device->dev);
        unsigned long long vgbs;
        int m;

        if (!intel_hid_evaluate_method(handle, INTEL_HID_DSM_VGBS_FN, &vgbs))
                return;

        m = !(vgbs & TABLET_MODE_FLAG);
        input_report_switch(priv->switches, SW_TABLET_MODE, m);
        input_sync(priv->switches);
}

static bool report_tablet_mode_event(struct input_dev *input_dev, u32 event)
{
        if (!input_dev)
                return false;

        switch (event) {
        case 0xcc:
                input_report_switch(input_dev, SW_TABLET_MODE, 1);
                input_sync(input_dev);
                return true;
        case 0xcd:
                input_report_switch(input_dev, SW_TABLET_MODE, 0);
                input_sync(input_dev);
                return true;
        default:
                return false;
        }
}

static void notify_handler(acpi_handle handle, u32 event, void *context)
{
        struct platform_device *device = context;
        struct intel_hid_priv *priv = dev_get_drvdata(&device->dev);
        unsigned long long ev_index;
        int err;

        /*
         * Some convertible have unreliable VGBS return which could cause incorrect
         * SW_TABLET_MODE report, in these cases we enable support when receiving
         * the first event instead of during driver setup.
         *
         * Some 360 degree hinges (yoga) style 2-in-1 devices use 2 accelerometers
         * to allow the OS to determine the angle between the display and the base
         * of the device. On Windows these are read by a special HingeAngleService
         * process which calls an ACPI DSM (Device Specific Method) on the
         * ACPI KIOX010A device node for the sensor in the display, to let the
         * firmware know if the 2-in-1 is in tablet- or laptop-mode so that it can
         * disable the kbd and touchpad to avoid spurious input in tablet-mode.
         *
         * The linux kxcjk1013 driver calls the DSM for this once at probe time
         * to ensure that the builtin kbd and touchpad work. On some devices this
         * causes a "spurious" 0xcd event on the intel-hid ACPI dev. In this case
         * there is not a functional tablet-mode switch, so we should not register
         * the tablet-mode switch device.
         */
        if (!priv->switches && (event == 0xcc || event == 0xcd) &&
            !acpi_dev_present("KIOX010A", NULL, -1)) {
                dev_info(&device->dev, "switch event received, enable switches supports\n");
                err = intel_hid_switches_setup(device);
                if (err)
                        pr_err("Failed to setup Intel HID switches\n");
        }

        if (priv->wakeup_mode) {
                /*
                 * Needed for wakeup from suspend-to-idle to work on some
                 * platforms that don't expose the 5-button array, but still
                 * send notifies with the power button event code to this
                 * device object on power button actions while suspended.
                 */
                if (event == 0xce)
                        goto wakeup;

                /*
                 * Switch events will wake the device and report the new switch
                 * position to the input subsystem.
                 */
                if (priv->switches && (event == 0xcc || event == 0xcd))
                        goto wakeup;

                /* Wake up on 5-button array events only. */
                if (event == 0xc0 || !priv->array)
                        return;

                if (!sparse_keymap_entry_from_scancode(priv->array, event)) {
                        dev_info(&device->dev, "unknown event 0x%x\n", event);
                        return;
                }

wakeup:
                pm_wakeup_hard_event(&device->dev);

                if (report_tablet_mode_event(priv->switches, event))
                        return;

                return;
        }

        /*
         * Needed for suspend to work on some platforms that don't expose
         * the 5-button array, but still send notifies with power button
         * event code to this device object on power button actions.
         *
         * Report the power button press and release.
         */
        if (!priv->array) {
                if (event == 0xce) {
                        input_report_key(priv->input_dev, KEY_POWER, 1);
                        input_sync(priv->input_dev);
                        return;
                }

                if (event == 0xcf) {
                        input_report_key(priv->input_dev, KEY_POWER, 0);
                        input_sync(priv->input_dev);
                        return;
                }
        }

        if (report_tablet_mode_event(priv->switches, event))
                return;

        /* 0xC0 is for HID events, other values are for 5 button array */
        if (event != 0xc0) {
                if (!priv->array ||
                    !sparse_keymap_report_event(priv->array, event, 1, true))
                        dev_dbg(&device->dev, "unknown event 0x%x\n", event);
                return;
        }

        if (!intel_hid_evaluate_method(handle, INTEL_HID_DSM_HDEM_FN,
                                       &ev_index)) {
                dev_warn(&device->dev, "failed to get event index\n");
                return;
        }

        if (!sparse_keymap_report_event(priv->input_dev, ev_index, 1, true))
                dev_dbg(&device->dev, "unknown event index 0x%llx\n",
                         ev_index);
}

static bool button_array_present(struct platform_device *device)
{
        acpi_handle handle = ACPI_HANDLE(&device->dev);
        unsigned long long event_cap;

        if (intel_hid_evaluate_method(handle, INTEL_HID_DSM_HEBC_V2_FN,
                                      &event_cap)) {
                /* Check presence of 5 button array or v2 power button */
                if (event_cap & 0x60000)
                        return true;
        }

        if (intel_hid_evaluate_method(handle, INTEL_HID_DSM_HEBC_V1_FN,
                                      &event_cap)) {
                if (event_cap & 0x20000)
                        return true;
        }

        if (dmi_check_system(button_array_table))
                return true;

        return false;
}

static int intel_hid_probe(struct platform_device *device)
{
        acpi_handle handle = ACPI_HANDLE(&device->dev);
        unsigned long long mode;
        struct intel_hid_priv *priv;
        acpi_status status;
        int err;

        intel_hid_init_dsm(handle);

        if (!intel_hid_evaluate_method(handle, INTEL_HID_DSM_HDMM_FN, &mode)) {
                dev_warn(&device->dev, "failed to read mode\n");
                return -ENODEV;
        }

        if (mode != 0) {
                /*
                 * This driver only implements "simple" mode.  There appear
                 * to be no other modes, but we should be paranoid and check
                 * for compatibility.
                 */
                dev_info(&device->dev, "platform is not in simple mode\n");
                return -ENODEV;
        }

        priv = devm_kzalloc(&device->dev, sizeof(*priv), GFP_KERNEL);
        if (!priv)
                return -ENOMEM;
        dev_set_drvdata(&device->dev, priv);

        err = intel_hid_input_setup(device);
        if (err) {
                pr_err("Failed to setup Intel HID hotkeys\n");
                return err;
        }

        /* Setup 5 button array */
        if (button_array_present(device)) {
                dev_info(&device->dev, "platform supports 5 button array\n");
                err = intel_button_array_input_setup(device);
                if (err)
                        pr_err("Failed to setup Intel 5 button array hotkeys\n");
        }

        /* Setup switches for devices that we know VGBS return correctly */
        if (dmi_check_system(dmi_vgbs_allow_list)) {
                dev_info(&device->dev, "platform supports switches\n");
                err = intel_hid_switches_setup(device);
                if (err)
                        pr_err("Failed to setup Intel HID switches\n");
                else
                        report_tablet_mode_state(device);
        }

        status = acpi_install_notify_handler(handle,
                                             ACPI_DEVICE_NOTIFY,
                                             notify_handler,
                                             device);
        if (ACPI_FAILURE(status))
                return -EBUSY;

        err = intel_hid_set_enable(&device->dev, true);
        if (err)
                goto err_remove_notify;

        if (priv->array) {
                unsigned long long dummy;

                intel_button_array_enable(&device->dev, true);

                /* Call button load method to enable HID power button */
                if (!intel_hid_evaluate_method(handle, INTEL_HID_DSM_BTNL_FN,
                                               &dummy)) {
                        dev_warn(&device->dev,
                                 "failed to enable HID power button\n");
                }
        }

        device_init_wakeup(&device->dev, true);
        /*
         * In order for system wakeup to work, the EC GPE has to be marked as
         * a wakeup one, so do that here (this setting will persist, but it has
         * no effect until the wakeup mask is set for the EC GPE).
         */
        acpi_ec_mark_gpe_for_wake();
        return 0;

err_remove_notify:
        acpi_remove_notify_handler(handle, ACPI_DEVICE_NOTIFY, notify_handler);

        return err;
}

static int intel_hid_remove(struct platform_device *device)
{
        acpi_handle handle = ACPI_HANDLE(&device->dev);

        device_init_wakeup(&device->dev, false);
        acpi_remove_notify_handler(handle, ACPI_DEVICE_NOTIFY, notify_handler);
        intel_hid_set_enable(&device->dev, false);
        intel_button_array_enable(&device->dev, false);

        /*
         * Even if we failed to shut off the event stream, we can still
         * safely detach from the device.
         */
        return 0;
}

static struct platform_driver intel_hid_pl_driver = {
        .driver = {
                .name = "intel-hid",
                .acpi_match_table = intel_hid_ids,
                .pm = &intel_hid_pl_pm_ops,
        },
        .probe = intel_hid_probe,
        .remove = intel_hid_remove,
};

/*
 * Unfortunately, some laptops provide a _HID="INT33D5" device with
 * _CID="PNP0C02".  This causes the pnpacpi scan driver to claim the
 * ACPI node, so no platform device will be created.  The pnpacpi
 * driver rejects this device in subsequent processing, so no physical
 * node is created at all.
 *
 * As a workaround until the ACPI core figures out how to handle
 * this corner case, manually ask the ACPI platform device code to
 * claim the ACPI node.
 */
static acpi_status __init
check_acpi_dev(acpi_handle handle, u32 lvl, void *context, void **rv)
{
        const struct acpi_device_id *ids = context;
        struct acpi_device *dev;

        if (acpi_bus_get_device(handle, &dev) != 0)
                return AE_OK;

        if (acpi_match_device_ids(dev, ids) == 0)
                if (!IS_ERR_OR_NULL(acpi_create_platform_device(dev, NULL)))
                        dev_info(&dev->dev,
                                 "intel-hid: created platform device\n");

        return AE_OK;
}

static int __init intel_hid_init(void)
{
        acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
                            ACPI_UINT32_MAX, check_acpi_dev, NULL,
                            (void *)intel_hid_ids, NULL);

        return platform_driver_register(&intel_hid_pl_driver);
}
module_init(intel_hid_init);

static void __exit intel_hid_exit(void)
{
        platform_driver_unregister(&intel_hid_pl_driver);
}
module_exit(intel_hid_exit);