/*
 * System76 ACPI Driver
 *
 * Copyright (C) 2019 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/init.h>
#include <linux/kernel.h>
#include <linux/leds.h>
#include <linux/module.h>
#include <linux/pci_ids.h>
#include <linux/types.h>

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;
};

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

static const enum led_brightness kb_levels[] = {
	48,
	72,
	96,
	144,
	192,
	255
};

static const int kb_colors[] = {
	0xFFFFFF,
	0x0000FF,
	0xFF0000,
	0xFF00FF,
	0x00FF00,
	0x00FFFF,
	0xFFFF00
};

static int system76_get(struct system76_data * data, char * method) {
	acpi_handle handle = acpi_device_handle(data->acpi_dev);

	unsigned long long ret = 0;
	acpi_status status = acpi_evaluate_integer(handle, method, NULL, &ret);
	if (ACPI_SUCCESS(status)) {
		return (int)ret;
	} else {
		return -1;
	}
}

static int system76_set(struct system76_data * data, char * method, int value) {
	acpi_handle handle = acpi_device_handle(data->acpi_dev);

	union acpi_object obj;
	obj.type = ACPI_TYPE_INTEGER;
	obj.integer.value = value;

	struct acpi_object_list obj_list;
	obj_list.count = 1;
	obj_list.pointer = &obj;

	acpi_status status = acpi_evaluate_object(handle, method, &obj_list, NULL);
	if (ACPI_SUCCESS(status)) {
		return 0;
	} else {
		return -1;
	}
}

static enum led_brightness ap_led_get(struct led_classdev * led) {
	struct system76_data * data = container_of(led, struct system76_data, ap_led);

	int value = system76_get(data, "GAPL");
	if (value > 0) {
		return (enum led_brightness)value;
	} else {
		return LED_OFF;
	}
}

static void ap_led_set(struct led_classdev * led, enum led_brightness value) {
	struct system76_data * data = container_of(led, struct system76_data, ap_led);

	system76_set(data, "SAPL", value == LED_OFF ? 0 : 1);
}

static enum led_brightness kb_led_get(struct led_classdev * led) {
	struct system76_data * data = container_of(led, struct system76_data, kb_led);

	return data->kb_brightness;
}

static void kb_led_set(struct led_classdev * led, enum led_brightness value) {
	struct system76_data * data = container_of(led, struct system76_data, kb_led);

	data->kb_brightness = value;
	system76_set(data, "SKBL", (int)data->kb_brightness);
}

static ssize_t kb_led_color_show(struct device * dev, struct device_attribute * dev_attr, char *buf) {
	struct led_classdev * led = (struct led_classdev *)dev->driver_data;
	struct system76_data * data = container_of(led, struct system76_data, kb_led);

	return sprintf(buf, "%06X\n", data->kb_color);
}

static ssize_t kb_led_color_store(struct device * dev, struct device_attribute * dev_attr, const char *buf, size_t size) {
	unsigned int val;
	int ret;

	struct led_classdev * led = (struct led_classdev *)dev->driver_data;
	struct system76_data * 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 const struct device_attribute kb_led_color_dev_attr = {
	.attr = {
		.name = "color",
		.mode = 0644,
	},
	.show = kb_led_color_show,
	.store = kb_led_color_store,
};

static void system76_notify(struct acpi_device *acpi_dev, u32 event) {
	int i;
	struct system76_data * data = acpi_driver_data(acpi_dev);

	if (event == 0x80) {
		// Keyboard LED change
		int value = system76_get(data, "GKBL");
		if (value >= 0) {
			data->kb_brightness = value;
			led_classdev_notify_brightness_hw_changed(&data->kb_led, data->kb_brightness);
		}
	} else if (event == 0x81) {
		// Backlight toggle
		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);
		}
		led_classdev_notify_brightness_hw_changed(&data->kb_led, data->kb_brightness);
	} else if (event == 0x82) {
		// Backlight down
		if (data->kb_brightness > 0) {
			for (i = sizeof(kb_levels)/sizeof(enum led_brightness); 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);
		}
		led_classdev_notify_brightness_hw_changed(&data->kb_led, data->kb_brightness);
	} else if (event == 0x83) {
		// Backlight up
		if (data->kb_brightness > 0) {
			for (i = 0; i < sizeof(kb_levels)/sizeof(enum led_brightness); 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);
		}
		led_classdev_notify_brightness_hw_changed(&data->kb_led, data->kb_brightness);
	} else if (event == 0x84) {
		// Backlight color
		if (data->kb_color >= 0) {
			if (data->kb_brightness > 0) {
				for (i = 0; i < sizeof(kb_colors)/sizeof(int); i++) {
					if (kb_colors[i] == data->kb_color) {
						break;
					}
				}
				i += 1;
				if (i >= sizeof(kb_colors)/sizeof(int)) {
					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);
			}
			led_classdev_notify_brightness_hw_changed(&data->kb_led, data->kb_brightness);
		}
	}
}

static int system76_add(struct acpi_device *acpi_dev) {
	int err;

	struct system76_data * data = devm_kzalloc(&acpi_dev->dev, sizeof(*data), GFP_KERNEL);
	if (!data) {
		return -ENOMEM;
	}
	acpi_dev->driver_data = data;
	data->acpi_dev = acpi_dev;

	data->ap_led.name = "system76::airplane";
	data->ap_led.flags = LED_CORE_SUSPENDRESUME;
	data->ap_led.brightness_get = ap_led_get;
	data->ap_led.brightness_set = ap_led_set;
	data->ap_led.max_brightness = 1;
	data->ap_led.default_trigger = "rfkill-none";
	err = devm_led_classdev_register(&acpi_dev->dev, &data->ap_led);
	if (err) {
		return err;
	}

	data->kb_led.name = "system76::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 = kb_led_set;
	if (acpi_has_method(acpi_device_handle(data->acpi_dev), "SKBC")) {
		data->kb_led.max_brightness = 255;
		data->kb_toggle_brightness = 72;
		data->kb_color = 0xffffff;
		system76_set(data, "SKBC", data->kb_color);
	} else {
		data->kb_led.max_brightness = 5;
		data->kb_color = -1;
	}
	err = devm_led_classdev_register(&acpi_dev->dev, &data->kb_led);
	if (err) {
		return err;
	}
	if (data->kb_color >= 0) {
		err = device_create_file(data->kb_led.dev, &kb_led_color_dev_attr);
		if (err) {
			return err;
		}
	}

	// Probe EC devices
	u8 d = 0;
	err = ec_transaction(0xA8, NULL, 0, &d, 1);
	if(err) {
		printk("system76-coreboot: failed to probe EC devices: %d\n", err);
	} else {
		printk("system76-coreboot: EC devices: 0x%x\n", d);
	}

	return 0;
}

static int system76_remove(struct acpi_device *acpi_dev) {
	struct system76_data *data = acpi_driver_data(acpi_dev);

	if (data->kb_color >= 0) {
		device_remove_file(data->kb_led.dev, &kb_led_color_dev_attr);
	}

	devm_led_classdev_unregister(&acpi_dev->dev, &data->ap_led);

	devm_led_classdev_unregister(&acpi_dev->dev, &data->kb_led);

	return 0;
}

static struct acpi_driver system76_driver = {
	.name = "System76 ACPI Driver",
	.class = "hotkey",
	.ids = device_ids,
	.ops = {
		.add = system76_add,
		.remove = system76_remove,
		.notify = system76_notify,
	},
};
module_acpi_driver(system76_driver);

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