[PATCH V2 2/2] LoongArch: Add ACPI-based generic laptop driver

[Huacai Chen <chenhuacai@loongson.cn>]

From: Jianmin Lv <lvjianmin@loongson.cn>

This add ACPI-based generic laptop driver for Loongson-3. Some of the
codes are derived from drivers/platform/x86/thinkpad_acpi.c.

Signed-off-by: Jianmin Lv <lvjianmin@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
---
V2: Fix problems pointed out by Arnd.

 drivers/platform/loongarch/Kconfig          |  12 +
 drivers/platform/loongarch/Makefile         |   1 +
 drivers/platform/loongarch/generic-laptop.c | 747 ++++++++++++++++++++
 3 files changed, 760 insertions(+)
 create mode 100644 drivers/platform/loongarch/generic-laptop.c

diff --git a/drivers/platform/loongarch/Kconfig b/drivers/platform/loongarch/Kconfig
index a1542843b0ad..61ed83227d36 100644
--- a/drivers/platform/loongarch/Kconfig
+++ b/drivers/platform/loongarch/Kconfig
@@ -23,4 +23,16 @@ config CPU_HWMON
 	help
 	  Loongson-3A/3B/3C CPU HWMon (temperature sensor) driver.
 
+config GENERIC_LAPTOP
+	tristate "Generic Loongson-3 Laptop Driver"
+	depends on ACPI
+	depends on BACKLIGHT_CLASS_DEVICE
+	depends on INPUT
+	depends on MACH_LOONGSON64
+	select INPUT_EVDEV
+	select INPUT_SPARSEKMAP
+	default y
+	help
+	  ACPI-based Loongson-3 family laptops generic driver.
+
 endif # LOONGARCH_PLATFORM_DEVICES
diff --git a/drivers/platform/loongarch/Makefile b/drivers/platform/loongarch/Makefile
index 8dfd03924c37..9d6f69f2319d 100644
--- a/drivers/platform/loongarch/Makefile
+++ b/drivers/platform/loongarch/Makefile
@@ -1 +1,2 @@
 obj-$(CONFIG_CPU_HWMON) += cpu_hwmon.o
+obj-$(CONFIG_GENERIC_LAPTOP) += generic-laptop.o
diff --git a/drivers/platform/loongarch/generic-laptop.c b/drivers/platform/loongarch/generic-laptop.c
new file mode 100644
index 000000000000..90c866f29702
--- /dev/null
+++ b/drivers/platform/loongarch/generic-laptop.c
@@ -0,0 +1,747 @@
+/*
+ *  Generic Loongson processor based LAPTOP/ALL-IN-ONE driver
+ *
+ *  Jianmin Lv <lvjianmin@loongson.cn>
+ *  Huacai Chen <chenhuacai@loongson.cn>
+ *
+ * Copyright (C) 2022 Loongson Technology Corporation Limited
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/string.h>
+#include <linux/platform_device.h>
+#include <linux/input.h>
+#include <linux/acpi.h>
+#include <linux/uaccess.h>
+#include <linux/input/sparse-keymap.h>
+#include <linux/device.h>
+#include <linux/backlight.h>
+#include <acpi/video.h>
+
+/* ACPI HIDs */
+#define LOONGSON_ACPI_HKEY_HID	"LOON0000"
+#define LOONGSON_ACPI_EC_HID	"PNP0C09"
+
+/* Main driver */
+
+#define ACPI_LAPTOP_VERSION "1.0"
+#define ACPI_LAPTOP_NAME "loongson-laptop"
+#define ACPI_LAPTOP_DESC "Loongson Laptop/all-in-one ACPI Driver"
+#define ACPI_LAPTOP_FILE ACPI_LAPTOP_NAME "_acpi"
+#define ACPI_LAPTOP_DRVR_NAME ACPI_LAPTOP_FILE
+#define ACPI_LAPTOP_ACPI_EVENT_PREFIX "loongson"
+
+/* Driver-wide structs and misc. variables */
+
+struct generic_struct;
+
+struct generic_acpi_drv_struct {
+	u32 type;
+	acpi_handle *handle;
+	const struct acpi_device_id *hid;
+	struct acpi_device *device;
+	struct acpi_driver *driver;
+	void (*notify)(struct generic_struct *, u32);
+};
+
+struct generic_struct {
+	char *name;
+
+	int (*init)(struct generic_struct *);
+
+	struct generic_acpi_drv_struct *acpi;
+
+	struct {
+		u8 acpi_driver_registered;
+		u8 acpi_notify_installed;
+	} flags;
+};
+
+
+static struct {
+	u32 input_device_registered:1;
+} generic_features;
+
+static int hotkey_status_get(int *status);
+static int loongson_laptop_backlight_update(struct backlight_device *bd);
+
+/* 1. ACPI Helpers and device model */
+
+/* ACPI basic handles */
+
+static acpi_handle ec_handle;
+
+#define GENERIC_HANDLE(object, parent, paths...)			\
+	static acpi_handle  object##_handle;			\
+	static const acpi_handle * const object##_parent __initconst =	\
+						&parent##_handle; \
+	static char *object##_paths[] __initdata = { paths }
+
+GENERIC_HANDLE(hkey, ec, "\\_SB.HKEY", "^HKEY", "HKEY",);
+
+/* ACPI device model */
+
+#define GENERIC_ACPIHANDLE_INIT(object) \
+	drv_acpi_handle_init(#object, &object##_handle, *object##_parent, \
+		object##_paths, ARRAY_SIZE(object##_paths))
+
+static void __init drv_acpi_handle_init(const char *name,
+			   acpi_handle *handle, const acpi_handle parent,
+			   char **paths, const int num_paths)
+{
+	int i;
+	acpi_status status;
+
+	for (i = 0; i < num_paths; i++) {
+		status = acpi_get_handle(parent, paths[i], handle);
+		if (ACPI_SUCCESS(status))
+			return;
+	}
+
+	*handle = NULL;
+}
+static acpi_status __init generic_acpi_handle_locate_callback(acpi_handle handle,
+					u32 level, void *context, void **return_value)
+{
+	*(acpi_handle *)return_value = handle;
+
+	return AE_CTRL_TERMINATE;
+}
+
+static void __init generic_acpi_handle_locate(const char *name,
+		const char *hid, acpi_handle *handle)
+{
+	acpi_status status;
+	acpi_handle device_found;
+
+	BUG_ON(!name || !hid || !handle);
+
+	*handle = NULL;
+
+	memset(&device_found, 0, sizeof(device_found));
+	status = acpi_get_devices(hid, generic_acpi_handle_locate_callback,
+				  (void *)name, &device_found);
+
+	if (ACPI_SUCCESS(status))
+		*handle = device_found;
+}
+
+static void dispatch_acpi_notify(acpi_handle handle, u32 event, void *data)
+{
+	struct generic_struct *sub_driver = data;
+
+	if (!sub_driver || !sub_driver->acpi || !sub_driver->acpi->notify)
+		return;
+	sub_driver->acpi->notify(sub_driver, event);
+}
+
+static int __init setup_acpi_notify(struct generic_struct *sub_driver)
+{
+	acpi_status status;
+
+	BUG_ON(!sub_driver->acpi);
+
+	if (!*sub_driver->acpi->handle)
+		return 0;
+
+	sub_driver->acpi->device = acpi_fetch_acpi_dev(*sub_driver->acpi->handle);
+	if (!sub_driver->acpi->device) {
+		pr_err("acpi_fetch_acpi_dev(%s) failed\n", sub_driver->name);
+		return -ENODEV;
+	}
+
+	sub_driver->acpi->device->driver_data = sub_driver;
+	sprintf(acpi_device_class(sub_driver->acpi->device), "%s/%s",
+		ACPI_LAPTOP_ACPI_EVENT_PREFIX,
+		sub_driver->name);
+
+	status = acpi_install_notify_handler(*sub_driver->acpi->handle,
+			sub_driver->acpi->type, dispatch_acpi_notify, sub_driver);
+	if (ACPI_FAILURE(status)) {
+		if (status == AE_ALREADY_EXISTS) {
+			pr_notice("Another device driver is already "
+				  "handling %s events\n", sub_driver->name);
+		} else {
+			pr_err("acpi_install_notify_handler(%s) failed: %s\n",
+			       sub_driver->name, acpi_format_exception(status));
+		}
+		return -ENODEV;
+	}
+	sub_driver->flags.acpi_notify_installed = 1;
+	return 0;
+}
+
+static int __init tpacpi_device_add(struct acpi_device *device)
+{
+	return 0;
+}
+
+static struct input_dev *generic_inputdev;
+
+static int loongson_generic_suspend(struct device *dev)
+{
+	return 0;
+}
+static int loongson_generic_resume(struct device *dev)
+{
+	int status = 0;
+	struct key_entry ke;
+	struct backlight_device *bd;
+
+	/*
+	 * Only if the firmware supports SW_LID event model, we can handle the
+	 * event. This is for the consideration of development board without
+	 * EC.
+	 */
+	if (test_bit(SW_LID, generic_inputdev->swbit)) {
+		if (hotkey_status_get(&status))
+			return -EIO;
+		/*
+		 * The input device sw element records the last lid status.
+		 * When the system is awakened by other wake-up sources,
+		 * the lid event will also be reported. The judgment of
+		 * adding SW_LID bit which in sw element can avoid this
+		 * case.
+		 *
+		 * input system will drop lid event when current lid event
+		 * value and last lid status in the same data set，which
+		 * data set inclue zero set and no zero set. so laptop
+		 * driver doesn't report repeated events.
+		 *
+		 * Lid status is generally 0, but hardware exception is
+		 * considered. So add lid status confirmation.
+		 */
+		if (test_bit(SW_LID, generic_inputdev->sw) && !(status & (1 << SW_LID))) {
+			ke.type = KE_SW;
+			ke.sw.value = (u8)status;
+			ke.sw.code = SW_LID;
+			sparse_keymap_report_entry(generic_inputdev, &ke,
+					1, true);
+		}
+	}
+
+	bd = backlight_device_get_by_type(BACKLIGHT_PLATFORM);
+	if (bd) {
+		loongson_laptop_backlight_update(bd) ?
+		pr_warn("Loongson_backlight: resume brightness failed") :
+		pr_info("Loongson_backlight: resume brightness %d\n", bd->props.brightness);
+	}
+
+	return 0;
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(loongson_generic_pm,
+		loongson_generic_suspend, loongson_generic_resume);
+
+static int __init register_generic_subdriver(struct generic_struct *sub_driver)
+{
+	int rc;
+
+	BUG_ON(!sub_driver->acpi);
+
+	sub_driver->acpi->driver = kzalloc(sizeof(struct acpi_driver), GFP_KERNEL);
+	if (!sub_driver->acpi->driver) {
+		pr_err("Failed to allocate memory for ibm->acpi->driver\n");
+		return -ENOMEM;
+	}
+
+	sprintf(sub_driver->acpi->driver->name, "%s_%s", ACPI_LAPTOP_NAME, sub_driver->name);
+	sub_driver->acpi->driver->ids = sub_driver->acpi->hid;
+	sub_driver->acpi->driver->ops.add = &tpacpi_device_add;
+	sub_driver->acpi->driver->drv.pm = pm_ptr(&loongson_generic_pm);
+	rc = acpi_bus_register_driver(sub_driver->acpi->driver);
+	if (rc < 0) {
+		pr_err("acpi_bus_register_driver(%s) failed: %d\n", sub_driver->name, rc);
+		kfree(sub_driver->acpi->driver);
+		sub_driver->acpi->driver = NULL;
+	} else if (!rc)
+		sub_driver->flags.acpi_driver_registered = 1;
+
+	return rc;
+}
+
+#define MAX_ACPI_ARGS 3
+
+static int acpi_evalf(acpi_handle handle,
+		      int *res, char *method, char *fmt, ...)
+{
+	char res_type;
+	char *fmt0 = fmt;
+	va_list ap;
+	int success, quiet;
+	acpi_status status;
+	struct acpi_object_list params;
+	struct acpi_buffer result, *resultp;
+	union acpi_object in_objs[MAX_ACPI_ARGS], out_obj;
+
+	if (!*fmt) {
+		pr_err("acpi_evalf() called with empty format\n");
+		return 0;
+	}
+
+	if (*fmt == 'q') {
+		quiet = 1;
+		fmt++;
+	} else
+		quiet = 0;
+
+	res_type = *(fmt++);
+
+	params.count = 0;
+	params.pointer = &in_objs[0];
+
+	va_start(ap, fmt);
+	while (*fmt) {
+		char c = *(fmt++);
+		switch (c) {
+		case 'd':	/* int */
+			in_objs[params.count].integer.value = va_arg(ap, int);
+			in_objs[params.count++].type = ACPI_TYPE_INTEGER;
+			break;
+			/* add more types as needed */
+		default:
+			pr_err("acpi_evalf() called with invalid format character '%c'\n",
+			       c);
+			va_end(ap);
+			return 0;
+		}
+	}
+	va_end(ap);
+
+	if (res_type != 'v') {
+		result.length = sizeof(out_obj);
+		result.pointer = &out_obj;
+		resultp = &result;
+	} else
+		resultp = NULL;
+
+	status = acpi_evaluate_object(handle, method, &params, resultp);
+
+	switch (res_type) {
+	case 'd':		/* int */
+		success = (status == AE_OK &&
+			   out_obj.type == ACPI_TYPE_INTEGER);
+		if (success && res)
+			*res = out_obj.integer.value;
+		break;
+	case 'v':		/* void */
+		success = status == AE_OK;
+		break;
+		/* add more types as needed */
+	default:
+		pr_err("acpi_evalf() called with invalid format character '%c'\n",
+		       res_type);
+		return 0;
+	}
+
+	if (!success && !quiet)
+		pr_err("acpi_evalf(%s, %s, ...) failed: %s\n",
+		       method, fmt0, acpi_format_exception(status));
+
+	return success;
+}
+
+/* Loongson generic laptop firmware event model */
+
+#define GENERIC_HOTKEY_MAP_MAX	64
+#define METHOD_NAME__KMAP	"KMAP"
+static struct key_entry hotkey_keycode_map[GENERIC_HOTKEY_MAP_MAX];
+
+static int hotkey_map(void)
+{
+	u32 index;
+	acpi_status status;
+	struct acpi_buffer buf;
+	union acpi_object *pack;
+
+	buf.length = ACPI_ALLOCATE_BUFFER;
+	status = acpi_evaluate_object_typed(hkey_handle, METHOD_NAME__KMAP, NULL, &buf, ACPI_TYPE_PACKAGE);
+	if (status != AE_OK) {
+		pr_err("ACPI exception: %s\n", acpi_format_exception(status));
+		return -1;
+	}
+	pack = buf.pointer;
+	for (index = 0; index < pack->package.count; index++) {
+		union acpi_object *sub_pack = &pack->package.elements[index];
+		union acpi_object *element = &sub_pack->package.elements[0];
+
+		hotkey_keycode_map[index].type = element->integer.value;
+		element = &sub_pack->package.elements[1];
+		hotkey_keycode_map[index].code = element->integer.value;
+		element = &sub_pack->package.elements[2];
+		hotkey_keycode_map[index].keycode = element->integer.value;
+	}
+
+	return 0;
+}
+
+static int hotkey_backlight_set(bool enable)
+{
+	if (!acpi_evalf(hkey_handle, NULL, "VCBL", "vd", enable ? 1 : 0))
+		return -EIO;
+
+	return 0;
+}
+
+static int __init event_init(struct generic_struct *sub_driver)
+{
+	int ret;
+
+	GENERIC_ACPIHANDLE_INIT(hkey);
+	ret = hotkey_map();
+	if (ret < 0) {
+		pr_err("Failed to parse keymap from DSDT\n");
+		return ret;
+	}
+
+	ret = sparse_keymap_setup(generic_inputdev, hotkey_keycode_map, NULL);
+	if (ret < 0) {
+		pr_err("Failed to setup input device keymap\n");
+		input_free_device(generic_inputdev);
+
+		return ret;
+	}
+
+	/*
+	 * This hotkey driver handle backlight event when
+	 * acpi_video_get_backlight_type() gets acpi_backlight_vendor
+	 */
+	if (acpi_video_get_backlight_type() != acpi_backlight_vendor)
+		hotkey_backlight_set(false);
+	else
+		hotkey_backlight_set(true);
+
+	pr_info("ACPI: enabling firmware HKEY event interface...\n");
+
+	return ret;
+}
+
+#define GENERIC_EVENT_TYPE_OFF		12
+#define GENERIC_EVENT_MASK		0xFFF
+
+static int ec_get_brightness(void)
+{
+	int status = 0;
+
+	if (!hkey_handle)
+		return -ENXIO;
+
+	if (!acpi_evalf(hkey_handle, &status, "ECBG", "d"))
+		return -EIO;
+
+	if (status < 0)
+		return status;
+
+	return status;
+}
+
+static int ec_set_brightness(int level)
+{
+
+	int ret = 0;
+
+	if (!hkey_handle)
+		return -ENXIO;
+
+	if (!acpi_evalf(hkey_handle, NULL, "ECBS", "vd", level))
+		ret = -EIO;
+
+	return ret;
+}
+
+static int ec_backlight_level(u8 level)
+{
+	int status = 0;
+
+	if (!hkey_handle)
+		return -ENXIO;
+
+	if (!acpi_evalf(hkey_handle, &status, "ECLL", "d"))
+		return -EIO;
+
+	if ((status < 0) || (level > status))
+		return status;
+
+	if (!acpi_evalf(hkey_handle, &status, "ECSL", "d"))
+		return -EIO;
+
+	if ((status < 0) || (level < status))
+		return status;
+
+	return level;
+}
+
+static int loongson_laptop_backlight_update(struct backlight_device *bd)
+{
+	int lvl = ec_backlight_level(bd->props.brightness);
+
+	if (lvl < 0)
+		return -EIO;
+	if (ec_set_brightness(lvl))
+		return -EIO;
+
+	return 0;
+}
+
+static int loongson_laptop_get_brightness(struct backlight_device *bd)
+{
+	u8 level;
+
+	level = ec_get_brightness();
+	if (level < 0)
+		return -EIO;
+
+	return level;
+}
+
+static const struct backlight_ops backlight_laptop_ops = {
+	.update_status = loongson_laptop_backlight_update,
+	.get_brightness = loongson_laptop_get_brightness,
+};
+
+static int laptop_backlight_register(void)
+{
+	int status = 0;
+	struct backlight_properties props;
+
+	memset(&props, 0, sizeof(props));
+	props.type = BACKLIGHT_PLATFORM;
+
+	if (!acpi_evalf(hkey_handle, &status, "ECLL", "d"))
+		return -EIO;
+
+	props.brightness = 1;
+	props.max_brightness = status;
+
+	backlight_device_register("loongson_laptop",
+				NULL, NULL, &backlight_laptop_ops, &props);
+
+	return 0;
+}
+
+int loongson_laptop_turn_on_backlight(void)
+{
+	int status;
+	union acpi_object arg0 = { ACPI_TYPE_INTEGER };
+	struct acpi_object_list args = { 1, &arg0 };
+
+	arg0.integer.value = 1;
+	status = acpi_evaluate_object(NULL, "\\BLSW", &args, NULL);
+	if (ACPI_FAILURE(status)) {
+		pr_info("Loongson lvds error: 0x%x\n", status);
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+int loongson_laptop_turn_off_backlight(void)
+{
+	int status;
+	union acpi_object arg0 = { ACPI_TYPE_INTEGER };
+	struct acpi_object_list args = { 1, &arg0 };
+
+	arg0.integer.value = 0;
+	status = acpi_evaluate_object(NULL, "\\BLSW", &args, NULL);
+	if (ACPI_FAILURE(status)) {
+		pr_info("Loongson lvds error: 0x%x\n", status);
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+static int hotkey_status_get(int *status)
+{
+	if (!acpi_evalf(hkey_handle, status, "GSWS", "d"))
+		return -EIO;
+
+	return 0;
+}
+
+static void event_notify(struct generic_struct *sub_driver, u32 event)
+{
+	struct key_entry *ke = NULL;
+	int scan_code = event & GENERIC_EVENT_MASK;
+	int type = (event >> GENERIC_EVENT_TYPE_OFF) & 0xF;
+
+	ke = sparse_keymap_entry_from_scancode(generic_inputdev, scan_code);
+	if (ke) {
+		if (type == KE_SW) {
+			int status = 0;
+
+			if (hotkey_status_get(&status))
+				return;
+
+			ke->sw.value = !!(status & (1 << ke->sw.code));
+		}
+		sparse_keymap_report_entry(generic_inputdev, ke, 1, true);
+	}
+}
+
+static const struct acpi_device_id loongson_htk_device_ids[] = {
+	{LOONGSON_ACPI_HKEY_HID, 0},
+	{"", 0},
+};
+
+static struct generic_acpi_drv_struct ec_event_acpidriver = {
+	.hid = loongson_htk_device_ids,
+	.notify = event_notify,
+	.handle = &hkey_handle,
+	.type = ACPI_DEVICE_NOTIFY,
+};
+
+/* 2. Infrastructure */
+
+static int __init probe_for_generic(void)
+{
+	if (acpi_disabled)
+		return -ENODEV;
+
+	/* The EC handler is required */
+	generic_acpi_handle_locate("ec", LOONGSON_ACPI_EC_HID, &ec_handle);
+	if (!ec_handle)
+		return -ENODEV;
+
+	return 0;
+}
+
+static void generic_exit(struct generic_struct *sub_driver)
+{
+
+	if (sub_driver->flags.acpi_notify_installed) {
+		BUG_ON(!sub_driver->acpi);
+		acpi_remove_notify_handler(*sub_driver->acpi->handle,
+					   sub_driver->acpi->type,
+					   dispatch_acpi_notify);
+		sub_driver->flags.acpi_notify_installed = 0;
+	}
+
+	if (sub_driver->flags.acpi_driver_registered) {
+		BUG_ON(!sub_driver->acpi);
+		acpi_bus_unregister_driver(sub_driver->acpi->driver);
+		kfree(sub_driver->acpi->driver);
+		sub_driver->acpi->driver = NULL;
+		sub_driver->flags.acpi_driver_registered = 0;
+	}
+
+}
+
+static int __init generic_subdriver_init(struct generic_struct *sub_driver)
+{
+	int ret;
+
+	BUG_ON(sub_driver == NULL);
+
+	if (sub_driver->init)
+		sub_driver->init(sub_driver);
+
+	if (sub_driver->acpi) {
+		if (sub_driver->acpi->hid) {
+			ret = register_generic_subdriver(sub_driver);
+			if (ret)
+				goto err_out;
+		}
+
+		if (sub_driver->acpi->notify) {
+			ret = setup_acpi_notify(sub_driver);
+			if (ret == -ENODEV) {
+				ret = 0;
+				goto err_out;
+			}
+			if (ret < 0)
+				goto err_out;
+		}
+	}
+
+	return 0;
+
+err_out:
+	generic_exit(sub_driver);
+	return (ret < 0) ? ret : 0;
+}
+
+/* Module init, exit, parameters */
+static struct generic_struct generic_sub_drivers[] __initdata = {
+	{
+		.name = "EC Event",
+		.init = event_init,
+		.acpi = &ec_event_acpidriver,
+	},
+};
+
+static void generic_acpi_laptop_exit(void);
+
+static int __init generic_acpi_laptop_init(void)
+{
+	int i, ret, status;
+
+	ret = probe_for_generic();
+	if (ret < 0)
+		return ret;
+
+	generic_inputdev = input_allocate_device();
+	if (!generic_inputdev) {
+		pr_err("Unable to allocate input device\n");
+		return -ENOMEM;
+	}
+
+	/* Prepare input device, but don't register */
+	generic_inputdev->name =
+		"Loongson Generic Laptop/All-in-one Extra Buttons";
+	generic_inputdev->phys = ACPI_LAPTOP_DRVR_NAME "/input0";
+	generic_inputdev->id.bustype = BUS_HOST;
+	generic_inputdev->dev.parent = NULL;
+
+	/* Init subdrivers */
+	for (i = 0; i < ARRAY_SIZE(generic_sub_drivers); i++) {
+		ret = generic_subdriver_init(&generic_sub_drivers[i]);
+		if (ret < 0) {
+			generic_acpi_laptop_exit();
+			return ret;
+		}
+	}
+
+	ret = input_register_device(generic_inputdev);
+	if (ret < 0) {
+		pr_err("Unable to register input device\n");
+		generic_acpi_laptop_exit();
+		return ret;
+	}
+
+	generic_features.input_device_registered = 1;
+
+	if (acpi_evalf(hkey_handle, &status, "ECBG", "d")) {
+		pr_info("Loongson Laptop used, init brightness is 0x%x\n", status);
+		ret = laptop_backlight_register();
+		if (ret < 0)
+			pr_err("Loongson Laptop: laptop-backlight device register failed\n");
+	}
+
+	return 0;
+}
+
+static void __exit generic_acpi_laptop_exit(void)
+{
+	if (generic_inputdev) {
+		if (generic_features.input_device_registered)
+			input_unregister_device(generic_inputdev);
+		else
+			input_free_device(generic_inputdev);
+	}
+}
+
+module_init(generic_acpi_laptop_init);
+module_exit(generic_acpi_laptop_exit);
+
+MODULE_ALIAS("platform:acpi-laptop");
+MODULE_AUTHOR("Jianmin Lv <lvjianmin@loongson.cn>");
+MODULE_AUTHOR("Huacai Chen <chenhuacai@loongson.cn>");
+MODULE_DESCRIPTION(ACPI_LAPTOP_DESC);
+MODULE_VERSION(ACPI_LAPTOP_VERSION);
+MODULE_LICENSE("GPL");
-- 
2.31.1