// SPDX-License-Identifier: GPL-2.0+
/*
 *  Intel Virtual Button driver for Windows 8.1+
 *
 *  Copyright (C) 2016 AceLan Kao <acelan.kao@canonical.com>
 *  Copyright (C) 2016 Alex Hung <alex.hung@canonical.com>
 */

#include <linux/acpi.h>
#include <linux/cleanup.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/mutex.h>
#include <linux/platform_device.h>
#include <linux/suspend.h>
#include "../dual_accel_detect.h"

/* Returned when NOT in tablet mode on some HP Stream x360 11 models */
#define VGBS_TABLET_MODE_FLAG_ALT       0x10
/* When NOT in tablet mode, VGBS returns with the flag 0x40 */
#define VGBS_TABLET_MODE_FLAG           0x40
#define VGBS_DOCK_MODE_FLAG             0x80

#define VGBS_TABLET_MODE_FLAGS (VGBS_TABLET_MODE_FLAG | VGBS_TABLET_MODE_FLAG_ALT)

MODULE_DESCRIPTION("Intel Virtual Button driver");
MODULE_LICENSE("GPL");
MODULE_AUTHOR("AceLan Kao");

static const struct acpi_device_id intel_vbtn_ids[] = {
        {"INT33D6", 0},
        {"", 0},
};
MODULE_DEVICE_TABLE(acpi, intel_vbtn_ids);

/* In theory, these are HID usages. */
static const struct key_entry intel_vbtn_keymap[] = {
        { KE_KEY, 0xC0, { KEY_POWER } },        /* power key press */
        { KE_IGNORE, 0xC1, { KEY_POWER } },     /* power key release */
        { KE_KEY, 0xC2, { KEY_LEFTMETA } },             /* 'Windows' key press */
        { KE_KEY, 0xC3, { KEY_LEFTMETA } },             /* 'Windows' key release */
        { KE_KEY, 0xC4, { KEY_VOLUMEUP } },             /* volume-up key press */
        { KE_IGNORE, 0xC5, { KEY_VOLUMEUP } },          /* volume-up key release */
        { KE_KEY, 0xC6, { KEY_VOLUMEDOWN } },           /* volume-down key press */
        { KE_IGNORE, 0xC7, { KEY_VOLUMEDOWN } },        /* volume-down key release */
        { KE_KEY,    0xC8, { KEY_ROTATE_LOCK_TOGGLE } },        /* rotate-lock key press */
        { KE_KEY,    0xC9, { KEY_ROTATE_LOCK_TOGGLE } },        /* rotate-lock key release */
        { KE_END }
};

static const struct key_entry intel_vbtn_switchmap[] = {
        /*
         * SW_DOCK should only be reported for docking stations, but DSDTs using the
         * intel-vbtn code, always seem to use this for 2-in-1s / convertibles and set
         * SW_DOCK=1 when in laptop-mode (in tandem with setting SW_TABLET_MODE=0).
         * This causes userspace to think the laptop is docked to a port-replicator
         * and to disable suspend-on-lid-close, which is undesirable.
         * Map the dock events to KEY_IGNORE to avoid this broken SW_DOCK reporting.
         */
        { KE_IGNORE, 0xCA, { .sw = { SW_DOCK, 1 } } },          /* Docked */
        { KE_IGNORE, 0xCB, { .sw = { SW_DOCK, 0 } } },          /* Undocked */
        { KE_SW,     0xCC, { .sw = { SW_TABLET_MODE, 1 } } },   /* Tablet */
        { KE_SW,     0xCD, { .sw = { SW_TABLET_MODE, 0 } } },   /* Laptop */
        { KE_END }
};

struct intel_vbtn_priv {
        struct mutex mutex; /* Avoid notify_handler() racing with itself */
        struct input_dev *buttons_dev;
        struct input_dev *switches_dev;
        bool dual_accel;
        bool has_buttons;
        bool has_switches;
        bool wakeup_mode;
};

static void detect_tablet_mode(struct device *dev)
{
        struct intel_vbtn_priv *priv = dev_get_drvdata(dev);
        acpi_handle handle = ACPI_HANDLE(dev);
        unsigned long long vgbs;
        acpi_status status;
        int m;

        status = acpi_evaluate_integer(handle, "VGBS", NULL, &vgbs);
        if (ACPI_FAILURE(status))
                return;

        m = !(vgbs & VGBS_TABLET_MODE_FLAGS);
        input_report_switch(priv->switches_dev, SW_TABLET_MODE, m);
        m = (vgbs & VGBS_DOCK_MODE_FLAG) ? 1 : 0;
        input_report_switch(priv->switches_dev, SW_DOCK, m);

        input_sync(priv->switches_dev);
}

/*
 * Note this unconditionally creates the 2 input_dev-s and sets up
 * the sparse-keymaps. Only the registration is conditional on
 * have_buttons / have_switches. This is done so that the notify
 * handler can always call sparse_keymap_entry_from_scancode()
 * on the input_dev-s do determine the event type.
 */
static int intel_vbtn_input_setup(struct platform_device *device)
{
        struct intel_vbtn_priv *priv = dev_get_drvdata(&device->dev);
        int ret;

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

        ret = sparse_keymap_setup(priv->buttons_dev, intel_vbtn_keymap, NULL);
        if (ret)
                return ret;

        priv->buttons_dev->dev.parent = &device->dev;
        priv->buttons_dev->name = "Intel Virtual Buttons";
        priv->buttons_dev->id.bustype = BUS_HOST;

        if (priv->has_buttons) {
                ret = input_register_device(priv->buttons_dev);
                if (ret)
                        return ret;
        }

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

        ret = sparse_keymap_setup(priv->switches_dev, intel_vbtn_switchmap, NULL);
        if (ret)
                return ret;

        priv->switches_dev->dev.parent = &device->dev;
        priv->switches_dev->name = "Intel Virtual Switches";
        priv->switches_dev->id.bustype = BUS_HOST;

        if (priv->has_switches) {
                ret = input_register_device(priv->switches_dev);
                if (ret)
                        return ret;
        }

        return 0;
}

static void notify_handler(acpi_handle handle, u32 event, void *context)
{
        struct platform_device *device = context;
        struct intel_vbtn_priv *priv = dev_get_drvdata(&device->dev);
        unsigned int val = !(event & 1); /* Even=press, Odd=release */
        const struct key_entry *ke, *ke_rel;
        struct input_dev *input_dev;
        bool autorelease;
        int ret;

        guard(mutex)(&priv->mutex);

        if ((ke = sparse_keymap_entry_from_scancode(priv->buttons_dev, event))) {
                if (!priv->has_buttons) {
                        dev_warn(&device->dev, "Warning: received 0x%02x button event on a device without buttons, please report this.\n",
                                 event);
                        return;
                }
                input_dev = priv->buttons_dev;
        } else if ((ke = sparse_keymap_entry_from_scancode(priv->switches_dev, event))) {
                if (!priv->has_switches) {
                        /* See dual_accel_detect.h for more info */
                        if (priv->dual_accel)
                                return;

                        dev_info(&device->dev, "Registering Intel Virtual Switches input-dev after receiving a switch event\n");
                        ret = input_register_device(priv->switches_dev);
                        if (ret)
                                return;

                        priv->has_switches = true;
                }
                input_dev = priv->switches_dev;
        } else {
                dev_dbg(&device->dev, "unknown event index 0x%x\n", event);
                return;
        }

        if (priv->wakeup_mode) {
                pm_wakeup_hard_event(&device->dev);

                /*
                 * Skip reporting an evdev event for button wake events,
                 * mirroring how the drivers/acpi/button.c code skips this too.
                 */
                if (ke->type == KE_KEY)
                        return;
        }

        /*
         * Even press events are autorelease if there is no corresponding odd
         * release event, or if the odd event is KE_IGNORE.
         */
        ke_rel = sparse_keymap_entry_from_scancode(input_dev, event | 1);
        autorelease = val && (!ke_rel || ke_rel->type == KE_IGNORE);

        sparse_keymap_report_event(input_dev, event, val, autorelease);
}

/*
 * There are several laptops (non 2-in-1) models out there which support VGBS,
 * but simply always return 0, which we translate to SW_TABLET_MODE=1. This in
 * turn causes userspace (libinput) to suppress events from the builtin
 * keyboard and touchpad, making the laptop essentially unusable.
 *
 * Since the problem of wrongly reporting SW_TABLET_MODE=1 in combination
 * with libinput, leads to a non-usable system. Where as OTOH many people will
 * not even notice when SW_TABLET_MODE is not being reported, a DMI based allow
 * list is used here. This list mainly matches on the chassis-type of 2-in-1s.
 *
 * There are also some 2-in-1s which use the intel-vbtn ACPI interface to report
 * SW_TABLET_MODE with a chassis-type of 8 ("Portable") or 10 ("Notebook"),
 * these are matched on a per model basis, since many normal laptops with a
 * possible broken VGBS ACPI-method also use these chassis-types.
 */
static const struct dmi_system_id dmi_switches_allow_list[] = {
        {
                .matches = {
                        DMI_EXACT_MATCH(DMI_CHASSIS_TYPE, "31" /* Convertible */),
                },
        },
        {
                .matches = {
                        DMI_EXACT_MATCH(DMI_CHASSIS_TYPE, "32" /* Detachable */),
                },
        },
        {
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
                        DMI_MATCH(DMI_PRODUCT_NAME, "Venue 11 Pro 7130"),
                },
        },
        {
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "HP Pavilion 13 x360 PC"),
                },
        },
        {
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "Switch SA5-271"),
                },
        },
        {
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
                        DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 7352"),
                },
        },
        {} /* Array terminator */
};

static bool intel_vbtn_has_switches(acpi_handle handle, bool dual_accel)
{
        /* See dual_accel_detect.h for more info */
        if (dual_accel)
                return false;

        if (!dmi_check_system(dmi_switches_allow_list))
                return false;

        return acpi_has_method(handle, "VGBS");
}

static int intel_vbtn_probe(struct platform_device *device)
{
        acpi_handle handle = ACPI_HANDLE(&device->dev);
        bool dual_accel, has_buttons, has_switches;
        struct intel_vbtn_priv *priv;
        acpi_status status;
        int err;

        dual_accel = dual_accel_detect();
        has_buttons = acpi_has_method(handle, "VBDL");
        has_switches = intel_vbtn_has_switches(handle, dual_accel);

        if (!has_buttons && !has_switches) {
                dev_warn(&device->dev, "failed to read Intel Virtual Button driver\n");
                return -ENODEV;
        }

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

        err = devm_mutex_init(&device->dev, &priv->mutex);
        if (err)
                return err;

        priv->dual_accel = dual_accel;
        priv->has_buttons = has_buttons;
        priv->has_switches = has_switches;

        err = intel_vbtn_input_setup(device);
        if (err) {
                pr_err("Failed to setup Intel Virtual Button\n");
                return err;
        }

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

        if (has_buttons) {
                status = acpi_evaluate_object(handle, "VBDL", NULL, NULL);
                if (ACPI_FAILURE(status))
                        dev_err(&device->dev, "Error VBDL failed with ACPI status %d\n", status);
        }
        // Check switches after buttons since VBDL may have side effects.
        if (has_switches)
                detect_tablet_mode(&device->dev);

        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;
}

static void intel_vbtn_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);
}

static int intel_vbtn_pm_prepare(struct device *dev)
{
        if (device_may_wakeup(dev)) {
                struct intel_vbtn_priv *priv = dev_get_drvdata(dev);

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

static void intel_vbtn_pm_complete(struct device *dev)
{
        struct intel_vbtn_priv *priv = dev_get_drvdata(dev);

        priv->wakeup_mode = false;
}

static int intel_vbtn_pm_resume(struct device *dev)
{
        struct intel_vbtn_priv *priv = dev_get_drvdata(dev);

        intel_vbtn_pm_complete(dev);

        if (priv->has_switches)
                detect_tablet_mode(dev);

        return 0;
}

static const struct dev_pm_ops intel_vbtn_pm_ops = {
        .prepare = intel_vbtn_pm_prepare,
        .complete = intel_vbtn_pm_complete,
        .resume = intel_vbtn_pm_resume,
        .restore = intel_vbtn_pm_resume,
        .thaw = intel_vbtn_pm_resume,
};

static struct platform_driver intel_vbtn_pl_driver = {
        .driver = {
                .name = "intel-vbtn",
                .acpi_match_table = intel_vbtn_ids,
                .pm = &intel_vbtn_pm_ops,
        },
        .probe = intel_vbtn_probe,
        .remove = intel_vbtn_remove,
};

module_platform_driver(intel_vbtn_pl_driver);