// SPDX-License-Identifier: GPL-2.0+
/*
 * System76 ACPI Driver
 *
 * Copyright (C) 2023 System76
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/acpi.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/init.h>
#include <linux/input.h>
#include <linux/kernel.h>
#include <linux/leds.h>
#include <linux/module.h>
#include <linux/pci_ids.h>
#include <linux/platform_device.h>
#include <linux/power_supply.h>
#include <linux/sysfs.h>
#include <linux/types.h>

#include <acpi/battery.h>

enum kbled_type {
	KBLED_NONE,
	KBLED_WHITE,
	KBLED_RGB,
};

struct system76_data {
	struct acpi_device *acpi_dev;
	struct led_classdev ap_led;
	struct led_classdev kb_led;
	enum led_brightness kb_brightness;
	enum led_brightness kb_toggle_brightness;
	int kb_color;
	struct device *therm;
	union acpi_object *nfan;
	union acpi_object *ntmp;
	struct input_dev *input;
	bool has_open_ec;
	enum kbled_type kbled_type;
};

static const struct acpi_device_id device_ids[] = {
	{"17761776", 0},
	{"", 0},
};
MODULE_DEVICE_TABLE(acpi, device_ids);

// Array of keyboard LED brightness levels
static const enum led_brightness kb_levels[] = {
	48,
	72,
	96,
	144,
	192,
	255
};

// Array of keyboard LED colors in 24-bit RGB format
static const int kb_colors[] = {
	0xFFFFFF,
	0x0000FF,
	0xFF0000,
	0xFF00FF,
	0x00FF00,
	0x00FFFF,
	0xFFFF00
};

// Get a System76 ACPI device value by name
static int system76_get(struct system76_data *data, char *method)
{
	acpi_handle handle;
	acpi_status status;
	unsigned long long ret = 0;

	handle = acpi_device_handle(data->acpi_dev);
	status = acpi_evaluate_integer(handle, method, NULL, &ret);
	if (ACPI_SUCCESS(status))
		return ret;
	return -ENODEV;
}

// Get a System76 ACPI device value by name with index
static int system76_get_index(struct system76_data *data, char *method, int index)
{
	union acpi_object obj;
	struct acpi_object_list obj_list;
	acpi_handle handle;
	acpi_status status;
	unsigned long long ret = 0;

	obj.type = ACPI_TYPE_INTEGER;
	obj.integer.value = index;
	obj_list.count = 1;
	obj_list.pointer = &obj;

	handle = acpi_device_handle(data->acpi_dev);
	status = acpi_evaluate_integer(handle, method, &obj_list, &ret);
	if (ACPI_SUCCESS(status))
		return ret;
	return -ENODEV;
}

// Get a System76 ACPI device object by name
static int system76_get_object(struct system76_data *data, char *method, union acpi_object **obj)
{
	acpi_handle handle;
	acpi_status status;
	struct acpi_buffer buf = { ACPI_ALLOCATE_BUFFER, NULL };

	handle = acpi_device_handle(data->acpi_dev);
	status = acpi_evaluate_object(handle, method, NULL, &buf);
	if (ACPI_SUCCESS(status)) {
		*obj = buf.pointer;
		return 0;
	}

	return -ENODEV;
}

// Get a name from a System76 ACPI device object
static char *system76_name(union acpi_object *obj, int index)
{
	if (obj && obj->type == ACPI_TYPE_PACKAGE && index <= obj->package.count) {
		if (obj->package.elements[index].type == ACPI_TYPE_STRING)
			return obj->package.elements[index].string.pointer;
	}

	return NULL;
}

// Set a System76 ACPI device value by name
static int system76_set(struct system76_data *data, char *method, int value)
{
	union acpi_object obj;
	struct acpi_object_list obj_list;
	acpi_handle handle;
	acpi_status status;

	obj.type = ACPI_TYPE_INTEGER;
	obj.integer.value = value;
	obj_list.count = 1;
	obj_list.pointer = &obj;
	handle = acpi_device_handle(data->acpi_dev);
	status = acpi_evaluate_object(handle, method, &obj_list, NULL);
	if (ACPI_SUCCESS(status))
		return 0;
	else
		return -1;
}

#define BATTERY_THRESHOLD_INVALID	0xFF

enum {
	THRESHOLD_START,
	THRESHOLD_END,
};

static ssize_t battery_get_threshold(int which, char *buf)
{
	struct acpi_object_list input;
	union acpi_object param;
	acpi_handle handle;
	acpi_status status;
	unsigned long long ret = BATTERY_THRESHOLD_INVALID;

	handle = ec_get_handle();
	if (!handle)
		return -ENODEV;

	input.count = 1;
	input.pointer = &param;
	// Start/stop selection
	param.type = ACPI_TYPE_INTEGER;
	param.integer.value = which;

	status = acpi_evaluate_integer(handle, "GBCT", &input, &ret);
	if (ACPI_FAILURE(status))
		return -EIO;
	if (ret == BATTERY_THRESHOLD_INVALID)
		return -EINVAL;

	return sysfs_emit(buf, "%d\n", (int)ret);
}

static ssize_t battery_set_threshold(int which, const char *buf, size_t count)
{
	struct acpi_object_list input;
	union acpi_object params[2];
	acpi_handle handle;
	acpi_status status;
	unsigned int value;
	int ret;

	handle = ec_get_handle();
	if (!handle)
		return -ENODEV;

	ret = kstrtouint(buf, 10, &value);
	if (ret)
		return ret;

	if (value > 100)
		return -EINVAL;

	input.count = 2;
	input.pointer = params;
	// Start/stop selection
	params[0].type = ACPI_TYPE_INTEGER;
	params[0].integer.value = which;
	// Threshold value
	params[1].type = ACPI_TYPE_INTEGER;
	params[1].integer.value = value;

	status = acpi_evaluate_object(handle, "SBCT", &input, NULL);
	if (ACPI_FAILURE(status))
		return -EIO;

	return count;
}

static ssize_t charge_control_start_threshold_show(struct device *dev,
	struct device_attribute *attr, char *buf)
{
	return battery_get_threshold(THRESHOLD_START, buf);
}

static ssize_t charge_control_start_threshold_store(struct device *dev,
	struct device_attribute *attr, const char *buf, size_t count)
{
	return battery_set_threshold(THRESHOLD_START, buf, count);
}

static DEVICE_ATTR_RW(charge_control_start_threshold);

static ssize_t charge_control_end_threshold_show(struct device *dev,
	struct device_attribute *attr, char *buf)
{
	return battery_get_threshold(THRESHOLD_END, buf);
}

static ssize_t charge_control_end_threshold_store(struct device *dev,
	struct device_attribute *attr, const char *buf, size_t count)
{
	return battery_set_threshold(THRESHOLD_END, buf, count);
}

static DEVICE_ATTR_RW(charge_control_end_threshold);

static struct attribute *system76_battery_attrs[] = {
	&dev_attr_charge_control_start_threshold.attr,
	&dev_attr_charge_control_end_threshold.attr,
	NULL,
};

ATTRIBUTE_GROUPS(system76_battery);

static int system76_battery_add(struct power_supply *battery, struct acpi_battery_hook *hook)
{
	// System76 EC only supports 1 battery
	if (strcmp(battery->desc->name, "BAT0") != 0)
		return -ENODEV;

	if (device_add_groups(&battery->dev, system76_battery_groups))
		return -ENODEV;

	return 0;
}

static int system76_battery_remove(struct power_supply *battery, struct acpi_battery_hook *hook)
{
	device_remove_groups(&battery->dev, system76_battery_groups);
	return 0;
}

static struct acpi_battery_hook system76_battery_hook = {
	.add_battery = system76_battery_add,
	.remove_battery = system76_battery_remove,
	.name = "System76 Battery Extension",
};

static void system76_battery_init(void)
{
	battery_hook_register(&system76_battery_hook);
}

static void system76_battery_exit(void)
{
	battery_hook_unregister(&system76_battery_hook);
}

// Get the airplane mode LED brightness
static enum led_brightness ap_led_get(struct led_classdev *led)
{
	struct system76_data *data;
	int value;

	data = container_of(led, struct system76_data, ap_led);
	value = system76_get(data, "GAPL");
	if (value > 0)
		return (enum led_brightness)value;
	else
		return LED_OFF;
}

// Set the airplane mode LED brightness
static int ap_led_set(struct led_classdev *led, enum led_brightness value)
{
	struct system76_data *data;

	data = container_of(led, struct system76_data, ap_led);
	return system76_set(data, "SAPL", value == LED_OFF ? 0 : 1);
}

// Get the last set keyboard LED brightness
static enum led_brightness kb_led_get(struct led_classdev *led)
{
	struct system76_data *data;

	data = container_of(led, struct system76_data, kb_led);
	return data->kb_brightness;
}

// Set the keyboard LED brightness
static int kb_led_set(struct led_classdev *led, enum led_brightness value)
{
	struct system76_data *data;

	data = container_of(led, struct system76_data, kb_led);
	data->kb_brightness = value;
	if (acpi_has_method(acpi_device_handle(data->acpi_dev), "GKBK")) {
		return system76_set(data, "SKBB", (int)data->kb_brightness);
	} else {
		return system76_set(data, "SKBL", (int)data->kb_brightness);
	}
}

// Get the last set keyboard LED color
static ssize_t kb_led_color_show(
	struct device *dev,
	struct device_attribute *dev_attr,
	char *buf)
{
	struct led_classdev *led;
	struct system76_data *data;

	led = dev_get_drvdata(dev);
	data = container_of(led, struct system76_data, kb_led);
	return sysfs_emit(buf, "%06X\n", data->kb_color);
}

// Set the keyboard LED color
static ssize_t kb_led_color_store(
	struct device *dev,
	struct device_attribute *dev_attr,
	const char *buf,
	size_t size)
{
	struct led_classdev *led;
	struct system76_data *data;
	unsigned int val;
	int ret;

	led = dev_get_drvdata(dev);
	data = container_of(led, struct system76_data, kb_led);
	ret = kstrtouint(buf, 16, &val);
	if (ret)
		return ret;
	if (val > 0xFFFFFF)
		return -EINVAL;
	data->kb_color = (int)val;
	system76_set(data, "SKBC", data->kb_color);

	return size;
}

static struct device_attribute dev_attr_kb_led_color = {
	.attr = {
		.name = "color",
		.mode = 0644,
	},
	.show = kb_led_color_show,
	.store = kb_led_color_store,
};

static struct attribute *system76_kb_led_color_attrs[] = {
	&dev_attr_kb_led_color.attr,
	NULL,
};

ATTRIBUTE_GROUPS(system76_kb_led_color);

// Notify that the keyboard LED was changed by hardware
static void kb_led_notify(struct system76_data *data)
{
	led_classdev_notify_brightness_hw_changed(
		&data->kb_led,
		data->kb_brightness
	);
}

// Read keyboard LED brightness as set by hardware
static void kb_led_hotkey_hardware(struct system76_data *data)
{
	int value;

	if (acpi_has_method(acpi_device_handle(data->acpi_dev), "GKBK")) {
		value = system76_get(data, "GKBB");
	} else {
		value = system76_get(data, "GKBL");
	}

	if (value < 0)
		return;
	data->kb_brightness = value;
	kb_led_notify(data);
}

// Toggle the keyboard LED
static void kb_led_hotkey_toggle(struct system76_data *data)
{
	if (data->kb_brightness > 0) {
		data->kb_toggle_brightness = data->kb_brightness;
		kb_led_set(&data->kb_led, 0);
	} else {
		kb_led_set(&data->kb_led, data->kb_toggle_brightness);
	}
	kb_led_notify(data);
}

// Decrease the keyboard LED brightness
static void kb_led_hotkey_down(struct system76_data *data)
{
	int i;

	if (data->kb_brightness > 0) {
		for (i = ARRAY_SIZE(kb_levels); i > 0; i--) {
			if (kb_levels[i - 1] < data->kb_brightness) {
				kb_led_set(&data->kb_led, kb_levels[i - 1]);
				break;
			}
		}
	} else {
		kb_led_set(&data->kb_led, data->kb_toggle_brightness);
	}
	kb_led_notify(data);
}

// Increase the keyboard LED brightness
static void kb_led_hotkey_up(struct system76_data *data)
{
	int i;

	if (data->kb_brightness > 0) {
		for (i = 0; i < ARRAY_SIZE(kb_levels); i++) {
			if (kb_levels[i] > data->kb_brightness) {
				kb_led_set(&data->kb_led, kb_levels[i]);
				break;
			}
		}
	} else {
		kb_led_set(&data->kb_led, data->kb_toggle_brightness);
	}
	kb_led_notify(data);
}

// Cycle the keyboard LED color
static void kb_led_hotkey_color(struct system76_data *data)
{
	int i;

	if (data->kbled_type != KBLED_RGB)
		return;

	if (data->kb_brightness > 0) {
		for (i = 0; i < ARRAY_SIZE(kb_colors); i++) {
			if (kb_colors[i] == data->kb_color)
				break;
		}
		i += 1;
		if (i >= ARRAY_SIZE(kb_colors))
			i = 0;
		data->kb_color = kb_colors[i];
		system76_set(data, "SKBC", data->kb_color);
	} else {
		kb_led_set(&data->kb_led, data->kb_toggle_brightness);
	}
	kb_led_notify(data);
}

static umode_t thermal_is_visible(const void *drvdata, enum hwmon_sensor_types type,
				  u32 attr, int channel)
{
	const struct system76_data *data = drvdata;

	switch (type) {
	case hwmon_fan:
	case hwmon_pwm:
		if (system76_name(data->nfan, channel))
			return 0444;
		break;

	case hwmon_temp:
		if (system76_name(data->ntmp, channel))
			return 0444;
		break;

	default:
		return 0;
	}

	return 0;
}

static int thermal_read(struct device *dev, enum hwmon_sensor_types type, u32 attr,
			int channel, long *val)
{
	struct system76_data *data = dev_get_drvdata(dev);
	int raw;

	switch (type) {
	case hwmon_fan:
		if (attr == hwmon_fan_input) {
			raw = system76_get_index(data, "GFAN", channel);
			if (raw < 0)
				return raw;
			*val = (raw >> 8) & 0xFFFF;
			return 0;
		}
		break;

	case hwmon_pwm:
		if (attr == hwmon_pwm_input) {
			raw = system76_get_index(data, "GFAN", channel);
			if (raw < 0)
				return raw;
			*val = raw & 0xFF;
			return 0;
		}
		break;

	case hwmon_temp:
		if (attr == hwmon_temp_input) {
			raw = system76_get_index(data, "GTMP", channel);
			if (raw < 0)
				return raw;
			*val = raw * 1000;
			return 0;
		}
		break;

	default:
		return -EOPNOTSUPP;
	}

	return -EOPNOTSUPP;
}

static int thermal_read_string(struct device *dev, enum hwmon_sensor_types type, u32 attr,
			       int channel, const char **str)
{
	struct system76_data *data = dev_get_drvdata(dev);

	switch (type) {
	case hwmon_fan:
		if (attr == hwmon_fan_label) {
			*str = system76_name(data->nfan, channel);
			if (*str)
				return 0;
		}
		break;

	case hwmon_temp:
		if (attr == hwmon_temp_label) {
			*str = system76_name(data->ntmp, channel);
			if (*str)
				return 0;
		}
		break;

	default:
		return -EOPNOTSUPP;
	}

	return -EOPNOTSUPP;
}

static const struct hwmon_ops thermal_ops = {
	.is_visible = thermal_is_visible,
	.read = thermal_read,
	.read_string = thermal_read_string,
};

// Allocate up to 8 fans and temperatures
static const struct hwmon_channel_info * const thermal_channel_info[] = {
	HWMON_CHANNEL_INFO(fan,
		HWMON_F_INPUT | HWMON_F_LABEL,
		HWMON_F_INPUT | HWMON_F_LABEL,
		HWMON_F_INPUT | HWMON_F_LABEL,
		HWMON_F_INPUT | HWMON_F_LABEL,
		HWMON_F_INPUT | HWMON_F_LABEL,
		HWMON_F_INPUT | HWMON_F_LABEL,
		HWMON_F_INPUT | HWMON_F_LABEL,
		HWMON_F_INPUT | HWMON_F_LABEL),
	HWMON_CHANNEL_INFO(pwm,
		HWMON_PWM_INPUT,
		HWMON_PWM_INPUT,
		HWMON_PWM_INPUT,
		HWMON_PWM_INPUT,
		HWMON_PWM_INPUT,
		HWMON_PWM_INPUT,
		HWMON_PWM_INPUT,
		HWMON_PWM_INPUT),
	HWMON_CHANNEL_INFO(temp,
		HWMON_T_INPUT | HWMON_T_LABEL,
		HWMON_T_INPUT | HWMON_T_LABEL,
		HWMON_T_INPUT | HWMON_T_LABEL,
		HWMON_T_INPUT | HWMON_T_LABEL,
		HWMON_T_INPUT | HWMON_T_LABEL,
		HWMON_T_INPUT | HWMON_T_LABEL,
		HWMON_T_INPUT | HWMON_T_LABEL,
		HWMON_T_INPUT | HWMON_T_LABEL),
	NULL
};

static const struct hwmon_chip_info thermal_chip_info = {
	.ops = &thermal_ops,
	.info = thermal_channel_info,
};

static void input_key(struct system76_data *data, unsigned int code)
{
	input_report_key(data->input, code, 1);
	input_sync(data->input);

	input_report_key(data->input, code, 0);
	input_sync(data->input);
}

// Handle ACPI notification
static void system76_notify(acpi_handle handle, u32 event, void *context)
{
	struct system76_data *data = context;

	switch (event) {
	case 0x80:
		kb_led_hotkey_hardware(data);
		break;
	case 0x81:
		kb_led_hotkey_toggle(data);
		break;
	case 0x82:
		kb_led_hotkey_down(data);
		break;
	case 0x83:
		kb_led_hotkey_up(data);
		break;
	case 0x84:
		kb_led_hotkey_color(data);
		break;
	case 0x85:
		input_key(data, KEY_SCREENLOCK);
		break;
	}
}

// Probe a System76 platform device
static int system76_probe(struct platform_device *pdev)
{
	struct acpi_device *acpi_dev;
	struct system76_data *data;
	int err;

	acpi_dev = ACPI_COMPANION(&pdev->dev);
	if (!acpi_dev)
		return -ENODEV;

	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
	if (!data)
		return -ENOMEM;

	platform_set_drvdata(pdev, data);

	data->acpi_dev = acpi_dev;

	// Some models do not run open EC firmware. Check for an ACPI method
	// that only exists on open EC to guard functionality specific to it.
	data->has_open_ec = acpi_has_method(acpi_device_handle(data->acpi_dev), "NFAN");

	err = system76_get(data, "INIT");
	if (err)
		return err;
	data->ap_led.name = "system76_acpi::airplane";
	data->ap_led.flags = LED_CORE_SUSPENDRESUME;
	data->ap_led.brightness_get = ap_led_get;
	data->ap_led.brightness_set_blocking = ap_led_set;
	data->ap_led.max_brightness = 1;
	data->ap_led.default_trigger = "rfkill-none";
	err = devm_led_classdev_register(&pdev->dev, &data->ap_led);
	if (err)
		return err;

	data->kb_led.name = "system76_acpi::kbd_backlight";
	data->kb_led.flags = LED_BRIGHT_HW_CHANGED | LED_CORE_SUSPENDRESUME;
	data->kb_led.brightness_get = kb_led_get;
	data->kb_led.brightness_set_blocking = kb_led_set;
	if (acpi_has_method(acpi_device_handle(data->acpi_dev), "GKBK")) {
		// Use the new ACPI methods
		data->kbled_type = system76_get(data, "GKBK");

		switch (data->kbled_type) {
		case KBLED_NONE:
			// Nothing to do: Device will not be registered.
			break;
		case KBLED_WHITE:
			data->kb_led.max_brightness = 255;
			data->kb_toggle_brightness = 72;
			break;
		case KBLED_RGB:
			data->kb_led.max_brightness = 255;
			data->kb_led.groups = system76_kb_led_color_groups;
			data->kb_toggle_brightness = 72;
			data->kb_color = 0xffffff;
			system76_set(data, "SKBC", data->kb_color);
			break;
		}
	} else {
		// Use the old ACPI methods
		if (acpi_has_method(acpi_device_handle(data->acpi_dev), "SKBC")) {
			data->kbled_type = KBLED_RGB;
			data->kb_led.max_brightness = 255;
			data->kb_led.groups = system76_kb_led_color_groups;
			data->kb_toggle_brightness = 72;
			data->kb_color = 0xffffff;
			system76_set(data, "SKBC", data->kb_color);
		} else {
			data->kbled_type = KBLED_WHITE;
			data->kb_led.max_brightness = 5;
		}
	}

	if (data->kbled_type != KBLED_NONE) {
		err = devm_led_classdev_register(&pdev->dev, &data->kb_led);
		if (err)
			return err;
	}

	data->input = devm_input_allocate_device(&pdev->dev);
	if (!data->input)
		return -ENOMEM;

	data->input->name = "System76 ACPI Hotkeys";
	data->input->phys = "system76_acpi/input0";
	data->input->id.bustype = BUS_HOST;
	data->input->dev.parent = &pdev->dev;
	input_set_capability(data->input, EV_KEY, KEY_SCREENLOCK);

	err = input_register_device(data->input);
	if (err)
		return err;

	err = acpi_dev_install_notify_handler(acpi_dev, ACPI_DEVICE_NOTIFY,
					      system76_notify, data);
	if (err)
		return err;

	if (data->has_open_ec) {
		err = system76_get_object(data, "NFAN", &data->nfan);
		if (err)
			goto error;

		err = system76_get_object(data, "NTMP", &data->ntmp);
		if (err)
			goto error;

		data->therm = devm_hwmon_device_register_with_info(&pdev->dev,
			"system76_acpi", data, &thermal_chip_info, NULL);
		err = PTR_ERR_OR_ZERO(data->therm);
		if (err)
			goto error;

		system76_battery_init();
	}

	return 0;

error:
	if (data->has_open_ec) {
		kfree(data->ntmp);
		kfree(data->nfan);
	}
	acpi_dev_remove_notify_handler(acpi_dev, ACPI_DEVICE_NOTIFY, system76_notify);
	return err;
}

// Remove a System76 platform device
static void system76_remove(struct platform_device *pdev)
{
	struct system76_data *data = platform_get_drvdata(pdev);

	if (data->has_open_ec) {
		system76_battery_exit();
		kfree(data->nfan);
		kfree(data->ntmp);
	}

	acpi_dev_remove_notify_handler(ACPI_COMPANION(&pdev->dev),
				       ACPI_DEVICE_NOTIFY, system76_notify);

	system76_get(data, "FINI");
}

static struct platform_driver system76_driver = {
	.probe = system76_probe,
	.remove = system76_remove,
	.driver = {
		.name = "System76 ACPI Driver",
		.acpi_match_table = device_ids,
	},
};
module_platform_driver(system76_driver);

MODULE_DESCRIPTION("System76 ACPI Driver");
MODULE_AUTHOR("Jeremy Soller <jeremy@system76.com>");
MODULE_LICENSE("GPL");
