// SPDX-License-Identifier: GPL-2.0+
/*
 * 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);

// 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 (int)ret;
        else
                return -1;
}

// 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;
}

// 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;
        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 = (struct led_classdev *)dev->driver_data;
        data = container_of(led, struct system76_data, kb_led);
        return sprintf(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 = (struct led_classdev *)dev->driver_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,
};

// 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;

        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->kb_color < 0)
                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);
}

// Handle ACPI notification
static void system76_notify(struct acpi_device *acpi_dev, u32 event)
{
        struct system76_data *data;

        data = acpi_driver_data(acpi_dev);
        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;
        }
}

// Add a System76 ACPI device
static int system76_add(struct acpi_device *acpi_dev)
{
        struct system76_data *data;
        int err;

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

        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(&acpi_dev->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), "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;
        }

        return 0;
}

// Remove a System76 ACPI device
static int system76_remove(struct acpi_device *acpi_dev)
{
        struct system76_data *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);

        system76_get(data, "FINI");

        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");