LoongArch: Add ACPI-based generic laptop driver

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>

drivers/platform/Kconfig

@@ -3,6 +3,8 @@ if MIPS
 source "drivers/platform/mips/Kconfig"
 endif
 
+source "drivers/platform/loongarch/Kconfig"
+
 source "drivers/platform/goldfish/Kconfig"
 
 source "drivers/platform/chrome/Kconfig"

drivers/platform/Makefile

@@ -4,6 +4,7 @@
 #
 
 obj-$(CONFIG_X86)		+= x86/
+obj-$(CONFIG_LOONGARCH)		+= loongarch/
 obj-$(CONFIG_MELLANOX_PLATFORM)	+= mellanox/
 obj-$(CONFIG_MIPS)		+= mips/
 obj-$(CONFIG_OLPC_EC)		+= olpc/

drivers/platform/loongarch/Kconfig

@@ -0,0 +1,31 @@
+#
+# LoongArch Platform Specific Drivers
+#
+
+menuconfig LOONGARCH_PLATFORM_DEVICES
+	bool "LoongArch Platform Specific Device Drivers"
+	default y
+	depends on LOONGARCH
+	help
+	  Say Y here to get to see options for device drivers of various
+	  LoongArch platforms, including vendor-specific laptop/desktop
+	  extension and hardware monitor drivers. This option itself does
+	  not add any kernel code.
+
+	  If you say N, all options in this submenu will be skipped and disabled.
+
+if LOONGARCH_PLATFORM_DEVICES
+
+config LOONGSON_LAPTOP
+	tristate "Generic Loongson-3 Laptop Driver"
+	depends on ACPI
+	depends on BACKLIGHT_CLASS_DEVICE
+	depends on INPUT
+	depends on MACH_LOONGSON64
+	select ACPI_VIDEO
+	select INPUT_SPARSEKMAP
+	default y
+	help
+	  ACPI-based Loongson-3 family laptops generic driver.
+
+endif # LOONGARCH_PLATFORM_DEVICES

drivers/platform/loongarch/Makefile

@@ -0,0 +1 @@
+obj-$(CONFIG_LOONGSON_LAPTOP) += loongson-laptop.o

drivers/platform/loongarch/loongson-laptop.c

@@ -0,0 +1,624 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  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/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/acpi.h>
+#include <linux/backlight.h>
+#include <linux/device.h>
+#include <linux/input.h>
+#include <linux/input/sparse-keymap.h>
+#include <linux/platform_device.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <acpi/video.h>
+
+/* 1. Driver-wide structs and misc. variables */
+
+/* ACPI HIDs */
+#define LOONGSON_ACPI_EC_HID	"PNP0C09"
+#define LOONGSON_ACPI_HKEY_HID	"LOON0000"
+
+#define ACPI_LAPTOP_NAME "loongson-laptop"
+#define ACPI_LAPTOP_ACPI_EVENT_PREFIX "loongson"
+
+#define MAX_ACPI_ARGS			3
+#define GENERIC_HOTKEY_MAP_MAX		64
+
+#define GENERIC_EVENT_TYPE_OFF		12
+#define GENERIC_EVENT_TYPE_MASK		0xF000
+#define GENERIC_EVENT_CODE_MASK		0x0FFF
+
+struct generic_sub_driver {
+	u32 type;
+	char *name;
+	acpi_handle *handle;
+	struct acpi_device *device;
+	struct platform_driver *driver;
+	int (*init)(struct generic_sub_driver *sub_driver);
+	void (*notify)(struct generic_sub_driver *sub_driver, u32 event);
+	u8 acpi_notify_installed;
+};
+
+static u32 input_device_registered;
+static struct input_dev *generic_inputdev;
+
+static acpi_handle hotkey_handle;
+static struct key_entry hotkey_keycode_map[GENERIC_HOTKEY_MAP_MAX];
+
+int loongson_laptop_turn_on_backlight(void);
+int loongson_laptop_turn_off_backlight(void);
+static int loongson_laptop_backlight_update(struct backlight_device *bd);
+
+/* 2. ACPI Helpers and device model */
+
+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;
+}
+
+static int hotkey_status_get(int *status)
+{
+	if (!acpi_evalf(hotkey_handle, status, "GSWS", "d"))
+		return -EIO;
+
+	return 0;
+}
+
+static void dispatch_acpi_notify(acpi_handle handle, u32 event, void *data)
+{
+	struct generic_sub_driver *sub_driver = data;
+
+	if (!sub_driver || !sub_driver->notify)
+		return;
+	sub_driver->notify(sub_driver, event);
+}
+
+static int __init setup_acpi_notify(struct generic_sub_driver *sub_driver)
+{
+	acpi_status status;
+
+	if (!*sub_driver->handle)
+		return 0;
+
+	sub_driver->device = acpi_fetch_acpi_dev(*sub_driver->handle);
+	if (!sub_driver->device) {
+		pr_err("acpi_fetch_acpi_dev(%s) failed\n", sub_driver->name);
+		return -ENODEV;
+	}
+
+	sub_driver->device->driver_data = sub_driver;
+	sprintf(acpi_device_class(sub_driver->device), "%s/%s",
+		ACPI_LAPTOP_ACPI_EVENT_PREFIX, sub_driver->name);
+
+	status = acpi_install_notify_handler(*sub_driver->handle,
+			sub_driver->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->acpi_notify_installed = 1;
+
+	return 0;
+}
+
+static int loongson_hotkey_suspend(struct device *dev)
+{
+	return 0;
+}
+
+static int loongson_hotkey_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) < 0)
+			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. 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_hotkey_pm,
+		loongson_hotkey_suspend, loongson_hotkey_resume);
+
+static int loongson_hotkey_probe(struct platform_device *pdev)
+{
+	hotkey_handle = ACPI_HANDLE(&pdev->dev);
+
+	if (!hotkey_handle)
+		return -ENODEV;
+
+	return 0;
+}
+
+static const struct acpi_device_id loongson_device_ids[] = {
+	{LOONGSON_ACPI_HKEY_HID, 0},
+	{"", 0},
+};
+MODULE_DEVICE_TABLE(acpi, loongson_device_ids);
+
+static struct platform_driver loongson_hotkey_driver = {
+	.probe		= loongson_hotkey_probe,
+	.driver		= {
+		.name	= "loongson-hotkey",
+		.owner	= THIS_MODULE,
+		.pm	= pm_ptr(&loongson_hotkey_pm),
+		.acpi_match_table = loongson_device_ids,
+	},
+};
+
+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(hotkey_handle, "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 *element, *sub_pack;
+
+		sub_pack = &pack->package.elements[index];
+
+		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(hotkey_handle, NULL, "VCBL", "vd", enable ? 1 : 0))
+		return -EIO;
+
+	return 0;
+}
+
+static int ec_get_brightness(void)
+{
+	int status = 0;
+
+	if (!hotkey_handle)
+		return -ENXIO;
+
+	if (!acpi_evalf(hotkey_handle, &status, "ECBG", "d"))
+		return -EIO;
+
+	return status;
+}
+
+static int ec_set_brightness(int level)
+{
+
+	int ret = 0;
+
+	if (!hotkey_handle)
+		return -ENXIO;
+
+	if (!acpi_evalf(hotkey_handle, NULL, "ECBS", "vd", level))
+		ret = -EIO;
+
+	return ret;
+}
+
+static int ec_backlight_level(u8 level)
+{
+	int status = 0;
+
+	if (!hotkey_handle)
+		return -ENXIO;
+
+	if (!acpi_evalf(hotkey_handle, &status, "ECLL", "d"))
+		return -EIO;
+
+	if ((status < 0) || (level > status))
+		return status;
+
+	if (!acpi_evalf(hotkey_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)
+{
+	int 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));
+
+	if (!acpi_evalf(hotkey_handle, &status, "ECLL", "d"))
+		return -EIO;
+
+	props.brightness = 1;
+	props.max_brightness = status;
+	props.type = BACKLIGHT_PLATFORM;
+
+	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 __init event_init(struct generic_sub_driver *sub_driver)
+{
+	int ret;
+
+	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(true);
+	else
+		hotkey_backlight_set(false);
+
+	pr_info("ACPI: enabling firmware HKEY event interface...\n");
+
+	return ret;
+}
+
+static void event_notify(struct generic_sub_driver *sub_driver, u32 event)
+{
+	int type, scan_code;
+	struct key_entry *ke = NULL;
+
+	scan_code = event & GENERIC_EVENT_CODE_MASK;
+	type = (event & GENERIC_EVENT_TYPE_MASK) >> GENERIC_EVENT_TYPE_OFF;
+	ke = sparse_keymap_entry_from_scancode(generic_inputdev, scan_code);
+	if (ke) {
+		if (type == KE_SW) {
+			int status = 0;
+
+			if (hotkey_status_get(&status) < 0)
+				return;
+
+			ke->sw.value = !!(status & (1 << ke->sw.code));
+		}
+		sparse_keymap_report_entry(generic_inputdev, ke, 1, true);
+	}
+}
+
+/* 3. Infrastructure */
+
+static void generic_subdriver_exit(struct generic_sub_driver *sub_driver);
+
+static int __init generic_subdriver_init(struct generic_sub_driver *sub_driver)
+{
+	int ret;
+
+	if (!sub_driver || !sub_driver->driver)
+		return -EINVAL;
+
+	ret = platform_driver_register(sub_driver->driver);
+	if (ret)
+		return -EINVAL;
+
+	if (sub_driver->init)
+		sub_driver->init(sub_driver);
+
+	if (sub_driver->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_subdriver_exit(sub_driver);
+	return (ret < 0) ? ret : 0;
+}
+
+static void generic_subdriver_exit(struct generic_sub_driver *sub_driver)
+{
+
+	if (sub_driver->acpi_notify_installed) {
+		acpi_remove_notify_handler(*sub_driver->handle,
+					   sub_driver->type, dispatch_acpi_notify);
+		sub_driver->acpi_notify_installed = 0;
+	}
+	platform_driver_unregister(sub_driver->driver);
+}
+
+static struct generic_sub_driver generic_sub_drivers[] __refdata = {
+	{
+		.name = "hotkey",
+		.init = event_init,
+		.notify = event_notify,
+		.handle = &hotkey_handle,
+		.type = ACPI_DEVICE_NOTIFY,
+		.driver = &loongson_hotkey_driver,
+	},
+};
+
+static int __init generic_acpi_laptop_init(void)
+{
+	bool ec_found;
+	int i, ret, status;
+
+	if (acpi_disabled)
+		return -ENODEV;
+
+	/* The EC device is required */
+	ec_found = acpi_dev_found(LOONGSON_ACPI_EC_HID);
+	if (!ec_found)
+		return -ENODEV;
+
+	/* Enable SCI for EC */
+	acpi_write_bit_register(ACPI_BITREG_SCI_ENABLE, 1);
+
+	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_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) {
+			input_free_device(generic_inputdev);
+			while (--i >= 0)
+				generic_subdriver_exit(&generic_sub_drivers[i]);
+			return ret;
+		}
+	}
+
+	ret = input_register_device(generic_inputdev);
+	if (ret < 0) {
+		input_free_device(generic_inputdev);
+		while (--i >= 0)
+			generic_subdriver_exit(&generic_sub_drivers[i]);
+		pr_err("Unable to register input device\n");
+		return ret;
+	}
+
+	input_device_registered = 1;
+
+	if (acpi_evalf(hotkey_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 (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_AUTHOR("Jianmin Lv <lvjianmin@loongson.cn>");
+MODULE_AUTHOR("Huacai Chen <chenhuacai@loongson.cn>");
+MODULE_DESCRIPTION("Loongson Laptop/All-in-One ACPI Driver");
+MODULE_LICENSE("GPL");