drivers/platform/x86/intel/vbtn.c - linux - Git at Google

 // 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_new = intel_vbtn_remove,
 };

 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 = acpi_fetch_acpi_dev(handle);

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

 	return AE_OK;
 }

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

 	return platform_driver_register(&intel_vbtn_pl_driver);
 }
 module_init(intel_vbtn_init);

 static void __exit intel_vbtn_exit(void)
 {
 	platform_driver_unregister(&intel_vbtn_pl_driver);
 }
 module_exit(intel_vbtn_exit);
	// 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_new = intel_vbtn_remove,
	};

	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 = acpi_fetch_acpi_dev(handle);

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

	return AE_OK;
	}

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

	return platform_driver_register(&intel_vbtn_pl_driver);
	}
	module_init(intel_vbtn_init);

	static void __exit intel_vbtn_exit(void)
	{
	platform_driver_unregister(&intel_vbtn_pl_driver);
	}
	module_exit(intel_vbtn_exit);