Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/drivers/platform/x86/xiaomi-wmi.c b/drivers/platform/x86/xiaomi-wmi.c
new file mode 100644
index 0000000..601cbb2
--- /dev/null
+++ b/drivers/platform/x86/xiaomi-wmi.c
@@ -0,0 +1,92 @@
+// SPDX-License-Identifier: GPL-2.0
+/* WMI driver for Xiaomi Laptops */
+
+#include <linux/acpi.h>
+#include <linux/input.h>
+#include <linux/module.h>
+#include <linux/wmi.h>
+
+#include <uapi/linux/input-event-codes.h>
+
+#define XIAOMI_KEY_FN_ESC_0	"A2095CCE-0491-44E7-BA27-F8ED8F88AA86"
+#define XIAOMI_KEY_FN_ESC_1	"7BBE8E39-B486-473D-BA13-66F75C5805CD"
+#define XIAOMI_KEY_FN_FN	"409B028D-F06B-4C7C-8BBB-EE133A6BD87E"
+#define XIAOMI_KEY_CAPSLOCK	"83FE7607-053A-4644-822A-21532C621FC7"
+#define XIAOMI_KEY_FN_F7	"76E9027C-95D0-4180-8692-DA6747DD1C2D"
+
+#define XIAOMI_DEVICE(guid, key)		\
+	.guid_string = (guid),			\
+	.context = &(const unsigned int){key}
+
+struct xiaomi_wmi {
+	struct input_dev *input_dev;
+	unsigned int key_code;
+};
+
+int xiaomi_wmi_probe(struct wmi_device *wdev, const void *context)
+{
+	struct xiaomi_wmi *data;
+
+	if (wdev == NULL || context == NULL)
+		return -EINVAL;
+
+	data = devm_kzalloc(&wdev->dev, sizeof(struct xiaomi_wmi), GFP_KERNEL);
+	if (data == NULL)
+		return -ENOMEM;
+	dev_set_drvdata(&wdev->dev, data);
+
+	data->input_dev = devm_input_allocate_device(&wdev->dev);
+	if (data->input_dev == NULL)
+		return -ENOMEM;
+	data->input_dev->name = "Xiaomi WMI keys";
+	data->input_dev->phys = "wmi/input0";
+
+	data->key_code = *((const unsigned int *)context);
+	set_bit(EV_KEY, data->input_dev->evbit);
+	set_bit(data->key_code, data->input_dev->keybit);
+
+	return input_register_device(data->input_dev);
+}
+
+void xiaomi_wmi_notify(struct wmi_device *wdev, union acpi_object *dummy)
+{
+	struct xiaomi_wmi *data;
+
+	if (wdev == NULL)
+		return;
+
+	data = dev_get_drvdata(&wdev->dev);
+	if (data == NULL)
+		return;
+
+	input_report_key(data->input_dev, data->key_code, 1);
+	input_sync(data->input_dev);
+	input_report_key(data->input_dev, data->key_code, 0);
+	input_sync(data->input_dev);
+}
+
+static const struct wmi_device_id xiaomi_wmi_id_table[] = {
+	// { XIAOMI_DEVICE(XIAOMI_KEY_FN_ESC_0, KEY_FN_ESC) },
+	// { XIAOMI_DEVICE(XIAOMI_KEY_FN_ESC_1, KEY_FN_ESC) },
+	{ XIAOMI_DEVICE(XIAOMI_KEY_FN_FN, KEY_PROG1) },
+	// { XIAOMI_DEVICE(XIAOMI_KEY_CAPSLOCK, KEY_CAPSLOCK) },
+	{ XIAOMI_DEVICE(XIAOMI_KEY_FN_F7, KEY_CUT) },
+
+	/* Terminating entry */
+	{ }
+};
+
+static struct wmi_driver xiaomi_wmi_driver = {
+	.driver = {
+		.name = "xiaomi-wmi",
+	},
+	.id_table = xiaomi_wmi_id_table,
+	.probe = xiaomi_wmi_probe,
+	.notify = xiaomi_wmi_notify,
+};
+module_wmi_driver(xiaomi_wmi_driver);
+
+MODULE_DEVICE_TABLE(wmi, xiaomi_wmi_id_table);
+MODULE_AUTHOR("Mattias Jacobsson");
+MODULE_DESCRIPTION("Xiaomi WMI driver");
+MODULE_LICENSE("GPL v2");