// SPDX-License-Identifier: GPL-2.0+

/* Platform driver for GPD devices that expose fan control via hwmon sysfs.
 *
 * Fan control is provided via pwm interface in the range [0-255].
 * Each model has a different range in the EC, the written value is scaled to
 * accommodate for that.
 *
 * Based on this repo:
 * https://github.com/Cryolitia/gpd-fan-driver
 *
 * Copyright (c) 2024 Cryolitia PukNgae
 */

#include <linux/dmi.h>
#include <linux/hwmon.h>
#include <linux/io.h>
#include <linux/ioport.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>

#define DRIVER_NAME "gpdfan"
#define GPD_PWM_CTR_OFFSET 0x1841

static char *gpd_fan_board = "";
module_param(gpd_fan_board, charp, 0444);

enum gpd_board {
        win_mini,
        win4_6800u,
        win_max_2,
        duo,
        mpc2,
};

enum FAN_PWM_ENABLE {
        DISABLE         = 0,
        MANUAL          = 1,
        AUTOMATIC       = 2,
};

static struct {
        enum FAN_PWM_ENABLE pwm_enable;
        u8 pwm_value;

        const struct gpd_fan_drvdata *drvdata;
} gpd_driver_priv;

struct gpd_fan_drvdata {
        const char *board_name; // Board name for module param comparison
        const enum gpd_board board;

        const u8 addr_port;
        const u8 data_port;
        const u16 manual_control_enable;
        const u16 rpm_read;
        const u16 pwm_write;
        const u16 pwm_max;
};

static struct gpd_fan_drvdata gpd_win_mini_drvdata = {
        .board_name             = "win_mini",
        .board                  = win_mini,

        .addr_port              = 0x4E,
        .data_port              = 0x4F,
        .manual_control_enable  = 0x047A,
        .rpm_read               = 0x0478,
        .pwm_write              = 0x047A,
        .pwm_max                = 244,
};

static struct gpd_fan_drvdata gpd_duo_drvdata = {
        .board_name             = "duo",
        .board                  = duo,

        .addr_port              = 0x4E,
        .data_port              = 0x4F,
        .manual_control_enable  = 0x047A,
        .rpm_read               = 0x0478,
        .pwm_write              = 0x047A,
        .pwm_max                = 244,
};

static struct gpd_fan_drvdata gpd_win4_drvdata = {
        .board_name             = "win4",
        .board                  = win4_6800u,

        .addr_port              = 0x2E,
        .data_port              = 0x2F,
        .manual_control_enable  = 0xC311,
        .rpm_read               = 0xC880,
        .pwm_write              = 0xC311,
        .pwm_max                = 127,
};

static struct gpd_fan_drvdata gpd_wm2_drvdata = {
        .board_name             = "wm2",
        .board                  = win_max_2,

        .addr_port              = 0x4E,
        .data_port              = 0x4F,
        .manual_control_enable  = 0x0275,
        .rpm_read               = 0x0218,
        .pwm_write              = 0x1809,
        .pwm_max                = 184,
};

static struct gpd_fan_drvdata gpd_mpc2_drvdata = {
        .board_name             = "mpc2",
        .board                  = mpc2,

        .addr_port              = 0x4E,
        .data_port              = 0x4F,
        .manual_control_enable  = 0x047A,
        .rpm_read               = 0x0476,
        .pwm_write              = 0x047A,
        .pwm_max                = 244,
};

static const struct dmi_system_id dmi_table[] = {
        {
                // GPD Win Mini
                // GPD Win Mini with AMD Ryzen 8840U
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "GPD"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "G1617-01")
                },
                .driver_data = &gpd_win_mini_drvdata,
        },
        {
                // GPD Win Mini
                // GPD Win Mini with AMD Ryzen HX370
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "GPD"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "G1617-02")
                },
                .driver_data = &gpd_win_mini_drvdata,
        },
        {
                // GPD Win Mini
                // GPD Win Mini with AMD Ryzen HX370
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "GPD"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "G1617-02-L")
                },
                .driver_data = &gpd_win_mini_drvdata,
        },
        {
                // GPD Win 4 with AMD Ryzen 6800U
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "GPD"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "G1618-04"),
                        DMI_MATCH(DMI_BOARD_VERSION, "Default string"),
                },
                .driver_data = &gpd_win4_drvdata,
        },
        {
                // GPD Win 4 with Ryzen 7840U
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "GPD"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "G1618-04"),
                        DMI_MATCH(DMI_BOARD_VERSION, "Ver. 1.0"),
                },
                // Since 7840U, win4 uses the same drvdata as wm2
                .driver_data = &gpd_wm2_drvdata,
        },
        {
                // GPD Win 4 with Ryzen 7840U (another)
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "GPD"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "G1618-04"),
                        DMI_MATCH(DMI_BOARD_VERSION, "Ver.1.0"),
                },
                .driver_data = &gpd_wm2_drvdata,
        },
        {
                // GPD Win Max 2 with Ryzen 6800U
                // GPD Win Max 2 2023 with Ryzen 7840U
                // GPD Win Max 2 2024 with Ryzen 8840U
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "GPD"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "G1619-04"),
                },
                .driver_data = &gpd_wm2_drvdata,
        },
        {
                // GPD Win Max 2 with AMD Ryzen HX370
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "GPD"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "G1619-05"),
                },
                .driver_data = &gpd_wm2_drvdata,
        },
        {
                // GPD Duo
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "GPD"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "G1622-01"),
                },
                .driver_data = &gpd_duo_drvdata,
        },
        {
                // GPD Duo (another)
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "GPD"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "G1622-01-L"),
                },
                .driver_data = &gpd_duo_drvdata,
        },
        {
                // GPD Pocket 4
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "GPD"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "G1628-04"),
                },
                .driver_data = &gpd_win_mini_drvdata,
        },
        {
                // GPD Pocket 4 (another)
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "GPD"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "G1628-04-L"),
                },
                .driver_data = &gpd_win_mini_drvdata,
        },
        {
                // GPD Micro PC 2
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "GPD"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "G1688-08"),
                },
                .driver_data = &gpd_mpc2_drvdata,
        },
        {}
};

static const struct gpd_fan_drvdata *gpd_module_drvdata[] = {
        &gpd_win_mini_drvdata, &gpd_win4_drvdata, &gpd_wm2_drvdata, &gpd_mpc2_drvdata, NULL
};

// Helper functions to handle EC read/write
static void gpd_ecram_read(u16 offset, u8 *val)
{
        u16 addr_port = gpd_driver_priv.drvdata->addr_port;
        u16 data_port = gpd_driver_priv.drvdata->data_port;

        outb(0x2E, addr_port);
        outb(0x11, data_port);
        outb(0x2F, addr_port);
        outb((u8)((offset >> 8) & 0xFF), data_port);

        outb(0x2E, addr_port);
        outb(0x10, data_port);
        outb(0x2F, addr_port);
        outb((u8)(offset & 0xFF), data_port);

        outb(0x2E, addr_port);
        outb(0x12, data_port);
        outb(0x2F, addr_port);
        *val = inb(data_port);
}

static void gpd_ecram_write(u16 offset, u8 value)
{
        u16 addr_port = gpd_driver_priv.drvdata->addr_port;
        u16 data_port = gpd_driver_priv.drvdata->data_port;

        outb(0x2E, addr_port);
        outb(0x11, data_port);
        outb(0x2F, addr_port);
        outb((u8)((offset >> 8) & 0xFF), data_port);

        outb(0x2E, addr_port);
        outb(0x10, data_port);
        outb(0x2F, addr_port);
        outb((u8)(offset & 0xFF), data_port);

        outb(0x2E, addr_port);
        outb(0x12, data_port);
        outb(0x2F, addr_port);
        outb(value, data_port);
}

static int gpd_generic_read_rpm(void)
{
        const struct gpd_fan_drvdata *const drvdata = gpd_driver_priv.drvdata;
        u8 high, low;

        gpd_ecram_read(drvdata->rpm_read, &high);
        gpd_ecram_read(drvdata->rpm_read + 1, &low);

        return (u16)high << 8 | low;
}

static int gpd_wm2_read_rpm(void)
{
        for (u16 pwm_ctr_offset = GPD_PWM_CTR_OFFSET;
             pwm_ctr_offset <= GPD_PWM_CTR_OFFSET + 2; pwm_ctr_offset++) {
                u8 PWMCTR;

                gpd_ecram_read(pwm_ctr_offset, &PWMCTR);

                if (PWMCTR != 0xB8)
                        gpd_ecram_write(pwm_ctr_offset, 0xB8);
        }

        return gpd_generic_read_rpm();
}

// Read value for fan1_input
static int gpd_read_rpm(void)
{
        switch (gpd_driver_priv.drvdata->board) {
        case win4_6800u:
        case win_mini:
        case duo:
        case mpc2:
                return gpd_generic_read_rpm();
        case win_max_2:
                return gpd_wm2_read_rpm();
        }

        return 0;
}

static int gpd_wm2_read_pwm(void)
{
        const struct gpd_fan_drvdata *const drvdata = gpd_driver_priv.drvdata;
        u8 var;

        gpd_ecram_read(drvdata->pwm_write, &var);

        // Match gpd_generic_write_pwm(u8) below
        return DIV_ROUND_CLOSEST((var - 1) * 255, (drvdata->pwm_max - 1));
}

// Read value for pwm1
static int gpd_read_pwm(void)
{
        switch (gpd_driver_priv.drvdata->board) {
        case win_mini:
        case duo:
        case win4_6800u:
        case mpc2:
                switch (gpd_driver_priv.pwm_enable) {
                case DISABLE:
                        return 255;
                case MANUAL:
                        return gpd_driver_priv.pwm_value;
                case AUTOMATIC:
                        return -EOPNOTSUPP;
                }
                break;
        case win_max_2:
                return gpd_wm2_read_pwm();
        }
        return 0;
}

// PWM value's range in EC is 1 - pwm_max, cast 0 - 255 to it.
static inline u8 gpd_cast_pwm_range(u8 val)
{
        const struct gpd_fan_drvdata *const drvdata = gpd_driver_priv.drvdata;

        return DIV_ROUND_CLOSEST(val * (drvdata->pwm_max - 1), 255) + 1;
}

static void gpd_generic_write_pwm(u8 val)
{
        const struct gpd_fan_drvdata *const drvdata = gpd_driver_priv.drvdata;
        u8 pwm_reg;

        pwm_reg = gpd_cast_pwm_range(val);
        gpd_ecram_write(drvdata->pwm_write, pwm_reg);
}

static void gpd_duo_write_pwm(u8 val)
{
        const struct gpd_fan_drvdata *const drvdata = gpd_driver_priv.drvdata;
        u8 pwm_reg;

        pwm_reg = gpd_cast_pwm_range(val);
        gpd_ecram_write(drvdata->pwm_write, pwm_reg);
        gpd_ecram_write(drvdata->pwm_write + 1, pwm_reg);
}

// Write value for pwm1
static int gpd_write_pwm(u8 val)
{
        if (gpd_driver_priv.pwm_enable != MANUAL)
                return -EPERM;

        switch (gpd_driver_priv.drvdata->board) {
        case duo:
                gpd_duo_write_pwm(val);
                break;
        case win_mini:
        case win4_6800u:
        case win_max_2:
        case mpc2:
                gpd_generic_write_pwm(val);
                break;
        }

        return 0;
}

static void gpd_win_mini_set_pwm_enable(enum FAN_PWM_ENABLE pwm_enable)
{
        switch (pwm_enable) {
        case DISABLE:
                gpd_generic_write_pwm(255);
                break;
        case MANUAL:
                gpd_generic_write_pwm(gpd_driver_priv.pwm_value);
                break;
        case AUTOMATIC:
                gpd_ecram_write(gpd_driver_priv.drvdata->pwm_write, 0);
                break;
        }
}

static void gpd_duo_set_pwm_enable(enum FAN_PWM_ENABLE pwm_enable)
{
        switch (pwm_enable) {
        case DISABLE:
                gpd_duo_write_pwm(255);
                break;
        case MANUAL:
                gpd_duo_write_pwm(gpd_driver_priv.pwm_value);
                break;
        case AUTOMATIC:
                gpd_ecram_write(gpd_driver_priv.drvdata->pwm_write, 0);
                break;
        }
}

static void gpd_wm2_set_pwm_enable(enum FAN_PWM_ENABLE enable)
{
        const struct gpd_fan_drvdata *const drvdata = gpd_driver_priv.drvdata;

        switch (enable) {
        case DISABLE:
                gpd_generic_write_pwm(255);
                gpd_ecram_write(drvdata->manual_control_enable, 1);
                break;
        case MANUAL:
                gpd_generic_write_pwm(gpd_driver_priv.pwm_value);
                gpd_ecram_write(drvdata->manual_control_enable, 1);
                break;
        case AUTOMATIC:
                gpd_ecram_write(drvdata->manual_control_enable, 0);
                break;
        }
}

// Write value for pwm1_enable
static void gpd_set_pwm_enable(enum FAN_PWM_ENABLE enable)
{
        if (enable == MANUAL)
                // Set pwm_value to max firstly when switching to manual mode, in
                // consideration of device safety.
                gpd_driver_priv.pwm_value = 255;

        switch (gpd_driver_priv.drvdata->board) {
        case win_mini:
        case win4_6800u:
        case mpc2:
                gpd_win_mini_set_pwm_enable(enable);
                break;
        case duo:
                gpd_duo_set_pwm_enable(enable);
                break;
        case win_max_2:
                gpd_wm2_set_pwm_enable(enable);
                break;
        }
}

static umode_t gpd_fan_hwmon_is_visible(__always_unused const void *drvdata,
                                        enum hwmon_sensor_types type, u32 attr,
                                        __always_unused int channel)
{
        if (type == hwmon_fan && attr == hwmon_fan_input) {
                return 0444;
        } else if (type == hwmon_pwm) {
                switch (attr) {
                case hwmon_pwm_enable:
                case hwmon_pwm_input:
                        return 0644;
                default:
                        return 0;
                }
        }
        return 0;
}

static int gpd_fan_hwmon_read(__always_unused struct device *dev,
                              enum hwmon_sensor_types type, u32 attr,
                              __always_unused int channel, long *val)
{
        int ret;

        if (type == hwmon_fan) {
                if (attr == hwmon_fan_input) {
                        ret = gpd_read_rpm();

                        if (ret < 0)
                                return ret;

                        *val = ret;
                        return 0;
                }
        } else if (type == hwmon_pwm) {
                switch (attr) {
                case hwmon_pwm_enable:
                        *val = gpd_driver_priv.pwm_enable;
                        return 0;
                case hwmon_pwm_input:
                        ret = gpd_read_pwm();

                        if (ret < 0)
                                return ret;

                        *val = ret;
                        return 0;
                }
        }

        return -EOPNOTSUPP;
}

static int gpd_fan_hwmon_write(__always_unused struct device *dev,
                               enum hwmon_sensor_types type, u32 attr,
                               __always_unused int channel, long val)
{
        if (type == hwmon_pwm) {
                switch (attr) {
                case hwmon_pwm_enable:
                        if (!in_range(val, 0, 3))
                                return -EINVAL;

                        gpd_driver_priv.pwm_enable = val;

                        gpd_set_pwm_enable(gpd_driver_priv.pwm_enable);
                        return 0;
                case hwmon_pwm_input:
                        if (!in_range(val, 0, 256))
                                return -EINVAL;

                        gpd_driver_priv.pwm_value = val;

                        return gpd_write_pwm(val);
                }
        }

        return -EOPNOTSUPP;
}

static const struct hwmon_ops gpd_fan_ops = {
        .is_visible = gpd_fan_hwmon_is_visible,
        .read = gpd_fan_hwmon_read,
        .write = gpd_fan_hwmon_write,
};

static const struct hwmon_channel_info *gpd_fan_hwmon_channel_info[] = {
        HWMON_CHANNEL_INFO(fan, HWMON_F_INPUT),
        HWMON_CHANNEL_INFO(pwm, HWMON_PWM_INPUT | HWMON_PWM_ENABLE),
        NULL
};

static struct hwmon_chip_info gpd_fan_chip_info = {
        .ops = &gpd_fan_ops,
        .info = gpd_fan_hwmon_channel_info
};

static void gpd_win4_init_ec(void)
{
        u8 chip_id, chip_ver;

        gpd_ecram_read(0x2000, &chip_id);

        if (chip_id == 0x55) {
                gpd_ecram_read(0x1060, &chip_ver);
                gpd_ecram_write(0x1060, chip_ver | 0x80);
        }
}

static void gpd_init_ec(void)
{
        // The buggy firmware won't initialize EC properly on boot.
        // Before its initialization, reading RPM will always return 0,
        // and writing PWM will have no effect.
        // Initialize it manually on driver load.
        if (gpd_driver_priv.drvdata->board == win4_6800u)
                gpd_win4_init_ec();
}

static int gpd_fan_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        const struct resource *region;
        const struct resource *res;
        const struct device *hwdev;

        res = platform_get_resource(pdev, IORESOURCE_IO, 0);
        if (!res)
                return dev_err_probe(dev, -EINVAL,
                                     "Failed to get platform resource\n");

        region = devm_request_region(dev, res->start,
                                     resource_size(res), DRIVER_NAME);
        if (!region)
                return dev_err_probe(dev, -EBUSY,
                                     "Failed to request region\n");

        hwdev = devm_hwmon_device_register_with_info(dev,
                                                     DRIVER_NAME,
                                                     NULL,
                                                     &gpd_fan_chip_info,
                                                     NULL);
        if (IS_ERR(hwdev))
                return dev_err_probe(dev, PTR_ERR(hwdev),
                                     "Failed to register hwmon device\n");

        gpd_init_ec();

        return 0;
}

static void gpd_fan_remove(__always_unused struct platform_device *pdev)
{
        gpd_driver_priv.pwm_enable = AUTOMATIC;
        gpd_set_pwm_enable(AUTOMATIC);
}

static struct platform_driver gpd_fan_driver = {
        .probe = gpd_fan_probe,
        .remove = gpd_fan_remove,
        .driver = {
                .name = KBUILD_MODNAME,
        },
};

static struct platform_device *gpd_fan_platform_device;

static int __init gpd_fan_init(void)
{
        const struct gpd_fan_drvdata *match = NULL;

        for (const struct gpd_fan_drvdata **p = gpd_module_drvdata; *p; p++) {
                if (strcmp(gpd_fan_board, (*p)->board_name) == 0) {
                        match = *p;
                        break;
                }
        }

        if (!match) {
                const struct dmi_system_id *dmi_match =
                        dmi_first_match(dmi_table);
                if (dmi_match)
                        match = dmi_match->driver_data;
        }

        if (!match)
                return -ENODEV;

        gpd_driver_priv.pwm_enable = AUTOMATIC;
        gpd_driver_priv.pwm_value = 255;
        gpd_driver_priv.drvdata = match;

        struct resource gpd_fan_resources[] = {
                {
                        .start = match->addr_port,
                        .end = match->data_port,
                        .flags = IORESOURCE_IO,
                },
        };

        gpd_fan_platform_device = platform_create_bundle(&gpd_fan_driver,
                                                         gpd_fan_probe,
                                                         gpd_fan_resources,
                                                         1, NULL, 0);

        if (IS_ERR(gpd_fan_platform_device)) {
                pr_warn("Failed to create platform device\n");
                return PTR_ERR(gpd_fan_platform_device);
        }

        return 0;
}

static void __exit gpd_fan_exit(void)
{
        platform_device_unregister(gpd_fan_platform_device);
        platform_driver_unregister(&gpd_fan_driver);
}

MODULE_DEVICE_TABLE(dmi, dmi_table);

module_init(gpd_fan_init);
module_exit(gpd_fan_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Cryolitia PukNgae <cryolitia@uniontech.com>");
MODULE_DESCRIPTION("GPD Devices fan control driver");