// 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");