v4.19.13 snapshot.
diff --git a/drivers/platform/x86/intel-vbtn.c b/drivers/platform/x86/intel-vbtn.c
new file mode 100644
index 0000000..06cd7e8
--- /dev/null
+++ b/drivers/platform/x86/intel-vbtn.c
@@ -0,0 +1,249 @@
+// 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/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 0x40
+#define DOCK_MODE_FLAG 0x80
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("AceLan Kao");
+
+static const struct acpi_device_id intel_vbtn_ids[] = {
+ {"INT33D6", 0},
+ {"", 0},
+};
+
+/* 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_SW, 0xCA, { .sw = { SW_DOCK, 1 } } }, /* Docked */
+ { KE_SW, 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 input_dev *input_dev;
+ bool wakeup_mode;
+};
+
+static int intel_vbtn_input_setup(struct platform_device *device)
+{
+ struct intel_vbtn_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_vbtn_keymap, NULL);
+ if (ret)
+ return ret;
+
+ priv->input_dev->dev.parent = &device->dev;
+ priv->input_dev->name = "Intel Virtual Button driver";
+ priv->input_dev->id.bustype = BUS_HOST;
+
+ return input_register_device(priv->input_dev);
+}
+
+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_rel;
+ bool autorelease;
+
+ if (priv->wakeup_mode) {
+ if (sparse_keymap_entry_from_scancode(priv->input_dev, event)) {
+ pm_wakeup_hard_event(&device->dev);
+ return;
+ }
+ goto out_unknown;
+ }
+
+ /*
+ * 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(priv->input_dev, event | 1);
+ autorelease = val && (!ke_rel || ke_rel->type == KE_IGNORE);
+
+ if (sparse_keymap_report_event(priv->input_dev, event, val, autorelease))
+ return;
+
+out_unknown:
+ dev_dbg(&device->dev, "unknown event index 0x%x\n", event);
+}
+
+static void detect_tablet_mode(struct platform_device *device)
+{
+ const char *chassis_type = dmi_get_system_info(DMI_CHASSIS_TYPE);
+ struct intel_vbtn_priv *priv = dev_get_drvdata(&device->dev);
+ acpi_handle handle = ACPI_HANDLE(&device->dev);
+ struct acpi_buffer vgbs_output = { ACPI_ALLOCATE_BUFFER, NULL };
+ union acpi_object *obj;
+ acpi_status status;
+ int m;
+
+ if (!(chassis_type && strcmp(chassis_type, "31") == 0))
+ goto out;
+
+ status = acpi_evaluate_object(handle, "VGBS", NULL, &vgbs_output);
+ if (ACPI_FAILURE(status))
+ goto out;
+
+ obj = vgbs_output.pointer;
+ if (!(obj && obj->type == ACPI_TYPE_INTEGER))
+ goto out;
+
+ m = !(obj->integer.value & TABLET_MODE_FLAG);
+ input_report_switch(priv->input_dev, SW_TABLET_MODE, m);
+ m = (obj->integer.value & DOCK_MODE_FLAG) ? 1 : 0;
+ input_report_switch(priv->input_dev, SW_DOCK, m);
+out:
+ kfree(vgbs_output.pointer);
+}
+
+static int intel_vbtn_probe(struct platform_device *device)
+{
+ acpi_handle handle = ACPI_HANDLE(&device->dev);
+ struct intel_vbtn_priv *priv;
+ acpi_status status;
+ int err;
+
+ status = acpi_evaluate_object(handle, "VBDL", NULL, NULL);
+ if (ACPI_FAILURE(status)) {
+ 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 = intel_vbtn_input_setup(device);
+ if (err) {
+ pr_err("Failed to setup Intel Virtual Button\n");
+ return err;
+ }
+
+ detect_tablet_mode(device);
+
+ status = acpi_install_notify_handler(handle,
+ ACPI_DEVICE_NOTIFY,
+ notify_handler,
+ device);
+ if (ACPI_FAILURE(status))
+ return -EBUSY;
+
+ device_init_wakeup(&device->dev, true);
+ return 0;
+}
+
+static int 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);
+
+ /*
+ * Even if we failed to shut off the event stream, we can still
+ * safely detach from the device.
+ */
+ return 0;
+}
+
+static int intel_vbtn_pm_prepare(struct device *dev)
+{
+ struct intel_vbtn_priv *priv = dev_get_drvdata(dev);
+
+ priv->wakeup_mode = true;
+ return 0;
+}
+
+static int intel_vbtn_pm_resume(struct device *dev)
+{
+ struct intel_vbtn_priv *priv = dev_get_drvdata(dev);
+
+ priv->wakeup_mode = false;
+ return 0;
+}
+
+static const struct dev_pm_ops intel_vbtn_pm_ops = {
+ .prepare = intel_vbtn_pm_prepare,
+ .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_DEVICE_TABLE(acpi, intel_vbtn_ids);
+
+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 (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);