// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * corsair-cpro.c - Linux driver for Corsair Commander Pro
 * Copyright (C) 2020 Marius Zachmann <mail@mariuszachmann.de>
 *
 * This driver uses hid reports to communicate with the device to allow hidraw userspace drivers
 * still being used. The device does not use report ids. When using hidraw and this driver
 * simultaniously, reports could be switched.
 */

#include <linux/bitops.h>
#include <linux/completion.h>
#include <linux/debugfs.h>
#include <linux/hid.h>
#include <linux/hwmon.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/seq_file.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/types.h>

#define USB_VENDOR_ID_CORSAIR                   0x1b1c
#define USB_PRODUCT_ID_CORSAIR_COMMANDERPRO     0x0c10
#define USB_PRODUCT_ID_CORSAIR_1000D            0x1d00

#define OUT_BUFFER_SIZE         63
#define IN_BUFFER_SIZE          16
#define LABEL_LENGTH            11
#define REQ_TIMEOUT             300

#define CTL_GET_FW_VER          0x02    /* returns the firmware version in bytes 1-3 */
#define CTL_GET_BL_VER          0x06    /* returns the bootloader version in bytes 1-2 */
#define CTL_GET_TMP_CNCT        0x10    /*
                                         * returns in bytes 1-4 for each temp sensor:
                                         * 0 not connected
                                         * 1 connected
                                         */
#define CTL_GET_TMP             0x11    /*
                                         * send: byte 1 is channel, rest zero
                                         * rcv:  returns temp for channel in centi-degree celsius
                                         * in bytes 1 and 2 as a two's complement value
                                         * returns 0x11 in byte 0 if no sensor is connected
                                         */
#define CTL_GET_VOLT            0x12    /*
                                         * send: byte 1 is rail number: 0 = 12v, 1 = 5v, 2 = 3.3v
                                         * rcv:  returns millivolt in bytes 1,2
                                         * returns error 0x10 if request is invalid
                                         */
#define CTL_GET_FAN_CNCT        0x20    /*
                                         * returns in bytes 1-6 for each fan:
                                         * 0 not connected
                                         * 1 3pin
                                         * 2 4pin
                                         */
#define CTL_GET_FAN_RPM         0x21    /*
                                         * send: byte 1 is channel, rest zero
                                         * rcv:  returns rpm in bytes 1,2
                                         */
#define CTL_GET_FAN_PWM         0x22    /*
                                         * send: byte 1 is channel, rest zero
                                         * rcv:  returns pwm in byte 1 if it was set
                                         *       returns error 0x12 if fan is controlled via
                                         *       fan_target or fan curve
                                         */
#define CTL_SET_FAN_FPWM        0x23    /*
                                         * set fixed pwm
                                         * send: byte 1 is fan number
                                         * send: byte 2 is percentage from 0 - 100
                                         */
#define CTL_SET_FAN_TARGET      0x24    /*
                                         * set target rpm
                                         * send: byte 1 is fan number
                                         * send: byte 2-3 is target
                                         * device accepts all values from 0x00 - 0xFFFF
                                         */

#define NUM_FANS                6
#define NUM_TEMP_SENSORS        4

struct ccp_device {
        struct hid_device *hdev;
        struct device *hwmon_dev;
        struct dentry *debugfs;
        /* For reinitializing the completion below */
        spinlock_t wait_input_report_lock;
        struct completion wait_input_report;
        struct mutex mutex; /* whenever buffer is used, lock before send_usb_cmd */
        u8 *cmd_buffer;
        u8 *buffer;
        int buffer_recv_size; /* number of received bytes in buffer */
        int target[NUM_FANS];
        DECLARE_BITMAP(temp_cnct, NUM_TEMP_SENSORS);
        DECLARE_BITMAP(fan_cnct, NUM_FANS);
        char fan_label[NUM_FANS][LABEL_LENGTH];
        u8 firmware_ver[3];
        u8 bootloader_ver[2];
};

/* converts response error in buffer to errno */
static int ccp_get_errno(struct ccp_device *ccp)
{
        switch (ccp->buffer[0]) {
        case 0x00: /* success */
                return 0;
        case 0x01: /* called invalid command */
                return -EOPNOTSUPP;
        case 0x10: /* called GET_VOLT / GET_TMP with invalid arguments */
                return -EINVAL;
        case 0x11: /* requested temps of disconnected sensors */
        case 0x12: /* requested pwm of not pwm controlled channels */
                return -ENODATA;
        default:
                hid_dbg(ccp->hdev, "unknown device response error: %d", ccp->buffer[0]);
                return -EIO;
        }
}

/* send command, check for error in response, response in ccp->buffer */
static int send_usb_cmd(struct ccp_device *ccp, u8 command, u8 byte1, u8 byte2, u8 byte3)
{
        unsigned long t;
        int ret;

        memset(ccp->cmd_buffer, 0x00, OUT_BUFFER_SIZE);
        ccp->cmd_buffer[0] = command;
        ccp->cmd_buffer[1] = byte1;
        ccp->cmd_buffer[2] = byte2;
        ccp->cmd_buffer[3] = byte3;

        /*
         * Disable raw event parsing for a moment to safely reinitialize the
         * completion. Reinit is done because hidraw could have triggered
         * the raw event parsing and marked the ccp->wait_input_report
         * completion as done.
         */
        spin_lock_bh(&ccp->wait_input_report_lock);
        reinit_completion(&ccp->wait_input_report);
        spin_unlock_bh(&ccp->wait_input_report_lock);

        ret = hid_hw_output_report(ccp->hdev, ccp->cmd_buffer, OUT_BUFFER_SIZE);
        if (ret < 0)
                return ret;

        t = wait_for_completion_timeout(&ccp->wait_input_report, msecs_to_jiffies(REQ_TIMEOUT));
        if (!t)
                return -ETIMEDOUT;

        if (ccp->buffer_recv_size != IN_BUFFER_SIZE)
                return -EPROTO;

        return ccp_get_errno(ccp);
}

static int ccp_raw_event(struct hid_device *hdev, struct hid_report *report, u8 *data, int size)
{
        struct ccp_device *ccp = hid_get_drvdata(hdev);

        /* only copy buffer when requested */
        spin_lock(&ccp->wait_input_report_lock);
        if (!completion_done(&ccp->wait_input_report)) {
                memcpy(ccp->buffer, data, min(IN_BUFFER_SIZE, size));
                ccp->buffer_recv_size = size;
                complete_all(&ccp->wait_input_report);
        }
        spin_unlock(&ccp->wait_input_report_lock);

        return 0;
}

/* requests and returns single data values depending on channel */
static int get_data(struct ccp_device *ccp, int command, int channel, bool two_byte_data)
{
        int ret;

        mutex_lock(&ccp->mutex);

        ret = send_usb_cmd(ccp, command, channel, 0, 0);
        if (ret)
                goto out_unlock;

        ret = ccp->buffer[1];
        if (two_byte_data)
                ret = (ret << 8) + ccp->buffer[2];

out_unlock:
        mutex_unlock(&ccp->mutex);
        return ret;
}

static int set_pwm(struct ccp_device *ccp, int channel, long val)
{
        int ret;

        if (val < 0 || val > 255)
                return -EINVAL;

        /* The Corsair Commander Pro uses values from 0-100 */
        val = DIV_ROUND_CLOSEST(val * 100, 255);

        mutex_lock(&ccp->mutex);

        ret = send_usb_cmd(ccp, CTL_SET_FAN_FPWM, channel, val, 0);
        if (!ret)
                ccp->target[channel] = -ENODATA;

        mutex_unlock(&ccp->mutex);
        return ret;
}

static int set_target(struct ccp_device *ccp, int channel, long val)
{
        int ret;

        val = clamp_val(val, 0, 0xFFFF);
        ccp->target[channel] = val;

        mutex_lock(&ccp->mutex);
        ret = send_usb_cmd(ccp, CTL_SET_FAN_TARGET, channel, val >> 8, val);

        mutex_unlock(&ccp->mutex);
        return ret;
}

static int ccp_read_string(struct device *dev, enum hwmon_sensor_types type,
                           u32 attr, int channel, const char **str)
{
        struct ccp_device *ccp = dev_get_drvdata(dev);

        switch (type) {
        case hwmon_fan:
                switch (attr) {
                case hwmon_fan_label:
                        *str = ccp->fan_label[channel];
                        return 0;
                default:
                        break;
                }
                break;
        default:
                break;
        }

        return -EOPNOTSUPP;
}

static int ccp_read(struct device *dev, enum hwmon_sensor_types type,
                    u32 attr, int channel, long *val)
{
        struct ccp_device *ccp = dev_get_drvdata(dev);
        int ret;

        switch (type) {
        case hwmon_temp:
                switch (attr) {
                case hwmon_temp_input:
                        ret = get_data(ccp, CTL_GET_TMP, channel, true);
                        if (ret < 0)
                                return ret;
                        *val = (s16)ret * 10;
                        return 0;
                default:
                        break;
                }
                break;
        case hwmon_fan:
                switch (attr) {
                case hwmon_fan_input:
                        ret = get_data(ccp, CTL_GET_FAN_RPM, channel, true);
                        if (ret < 0)
                                return ret;
                        *val = ret;
                        return 0;
                case hwmon_fan_target:
                        /* how to read target values from the device is unknown */
                        /* driver returns last set value or 0                   */
                        if (ccp->target[channel] < 0)
                                return -ENODATA;
                        *val = ccp->target[channel];
                        return 0;
                default:
                        break;
                }
                break;
        case hwmon_pwm:
                switch (attr) {
                case hwmon_pwm_input:
                        ret = get_data(ccp, CTL_GET_FAN_PWM, channel, false);
                        if (ret < 0)
                                return ret;
                        *val = DIV_ROUND_CLOSEST(ret * 255, 100);
                        return 0;
                default:
                        break;
                }
                break;
        case hwmon_in:
                switch (attr) {
                case hwmon_in_input:
                        ret = get_data(ccp, CTL_GET_VOLT, channel, true);
                        if (ret < 0)
                                return ret;
                        *val = ret;
                        return 0;
                default:
                        break;
                }
                break;
        default:
                break;
        }

        return -EOPNOTSUPP;
};

static int ccp_write(struct device *dev, enum hwmon_sensor_types type,
                     u32 attr, int channel, long val)
{
        struct ccp_device *ccp = dev_get_drvdata(dev);

        switch (type) {
        case hwmon_pwm:
                switch (attr) {
                case hwmon_pwm_input:
                        return set_pwm(ccp, channel, val);
                default:
                        break;
                }
                break;
        case hwmon_fan:
                switch (attr) {
                case hwmon_fan_target:
                        return set_target(ccp, channel, val);
                default:
                        break;
                }
                break;
        default:
                break;
        }

        return -EOPNOTSUPP;
};

static umode_t ccp_is_visible(const void *data, enum hwmon_sensor_types type,
                              u32 attr, int channel)
{
        const struct ccp_device *ccp = data;

        switch (type) {
        case hwmon_temp:
                if (!test_bit(channel, ccp->temp_cnct))
                        break;

                switch (attr) {
                case hwmon_temp_input:
                        return 0444;
                case hwmon_temp_label:
                        return 0444;
                default:
                        break;
                }
                break;
        case hwmon_fan:
                if (!test_bit(channel, ccp->fan_cnct))
                        break;

                switch (attr) {
                case hwmon_fan_input:
                        return 0444;
                case hwmon_fan_label:
                        return 0444;
                case hwmon_fan_target:
                        return 0644;
                default:
                        break;
                }
                break;
        case hwmon_pwm:
                if (!test_bit(channel, ccp->fan_cnct))
                        break;

                switch (attr) {
                case hwmon_pwm_input:
                        return 0644;
                default:
                        break;
                }
                break;
        case hwmon_in:
                switch (attr) {
                case hwmon_in_input:
                        return 0444;
                default:
                        break;
                }
                break;
        default:
                break;
        }

        return 0;
};

static const struct hwmon_ops ccp_hwmon_ops = {
        .is_visible = ccp_is_visible,
        .read = ccp_read,
        .read_string = ccp_read_string,
        .write = ccp_write,
};

static const struct hwmon_channel_info * const ccp_info[] = {
        HWMON_CHANNEL_INFO(chip,
                           HWMON_C_REGISTER_TZ),
        HWMON_CHANNEL_INFO(temp,
                           HWMON_T_INPUT,
                           HWMON_T_INPUT,
                           HWMON_T_INPUT,
                           HWMON_T_INPUT
                           ),
        HWMON_CHANNEL_INFO(fan,
                           HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_TARGET,
                           HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_TARGET,
                           HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_TARGET,
                           HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_TARGET,
                           HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_TARGET,
                           HWMON_F_INPUT | HWMON_F_LABEL | HWMON_F_TARGET
                           ),
        HWMON_CHANNEL_INFO(pwm,
                           HWMON_PWM_INPUT,
                           HWMON_PWM_INPUT,
                           HWMON_PWM_INPUT,
                           HWMON_PWM_INPUT,
                           HWMON_PWM_INPUT,
                           HWMON_PWM_INPUT
                           ),
        HWMON_CHANNEL_INFO(in,
                           HWMON_I_INPUT,
                           HWMON_I_INPUT,
                           HWMON_I_INPUT
                           ),
        NULL
};

static const struct hwmon_chip_info ccp_chip_info = {
        .ops = &ccp_hwmon_ops,
        .info = ccp_info,
};

/* read fan connection status and set labels */
static int get_fan_cnct(struct ccp_device *ccp)
{
        int channel;
        int mode;
        int ret;

        ret = send_usb_cmd(ccp, CTL_GET_FAN_CNCT, 0, 0, 0);
        if (ret)
                return ret;

        for (channel = 0; channel < NUM_FANS; channel++) {
                mode = ccp->buffer[channel + 1];
                if (mode == 0)
                        continue;

                set_bit(channel, ccp->fan_cnct);
                ccp->target[channel] = -ENODATA;

                switch (mode) {
                case 1:
                        scnprintf(ccp->fan_label[channel], LABEL_LENGTH,
                                  "fan%d 3pin", channel + 1);
                        break;
                case 2:
                        scnprintf(ccp->fan_label[channel], LABEL_LENGTH,
                                  "fan%d 4pin", channel + 1);
                        break;
                default:
                        scnprintf(ccp->fan_label[channel], LABEL_LENGTH,
                                  "fan%d other", channel + 1);
                        break;
                }
        }

        return 0;
}

/* read temp sensor connection status */
static int get_temp_cnct(struct ccp_device *ccp)
{
        int channel;
        int mode;
        int ret;

        ret = send_usb_cmd(ccp, CTL_GET_TMP_CNCT, 0, 0, 0);
        if (ret)
                return ret;

        for (channel = 0; channel < NUM_TEMP_SENSORS; channel++) {
                mode = ccp->buffer[channel + 1];
                if (mode == 0)
                        continue;

                set_bit(channel, ccp->temp_cnct);
        }

        return 0;
}

/* read firmware version */
static int get_fw_version(struct ccp_device *ccp)
{
        int ret;

        ret = send_usb_cmd(ccp, CTL_GET_FW_VER, 0, 0, 0);
        if (ret) {
                hid_notice(ccp->hdev, "Failed to read firmware version.\n");
                return ret;
        }
        ccp->firmware_ver[0] = ccp->buffer[1];
        ccp->firmware_ver[1] = ccp->buffer[2];
        ccp->firmware_ver[2] = ccp->buffer[3];

        return 0;
}

/* read bootloader version */
static int get_bl_version(struct ccp_device *ccp)
{
        int ret;

        ret = send_usb_cmd(ccp, CTL_GET_BL_VER, 0, 0, 0);
        if (ret) {
                hid_notice(ccp->hdev, "Failed to read bootloader version.\n");
                return ret;
        }
        ccp->bootloader_ver[0] = ccp->buffer[1];
        ccp->bootloader_ver[1] = ccp->buffer[2];

        return 0;
}

static int firmware_show(struct seq_file *seqf, void *unused)
{
        struct ccp_device *ccp = seqf->private;

        seq_printf(seqf, "%d.%d.%d\n",
                   ccp->firmware_ver[0],
                   ccp->firmware_ver[1],
                   ccp->firmware_ver[2]);

        return 0;
}
DEFINE_SHOW_ATTRIBUTE(firmware);

static int bootloader_show(struct seq_file *seqf, void *unused)
{
        struct ccp_device *ccp = seqf->private;

        seq_printf(seqf, "%d.%d\n",
                   ccp->bootloader_ver[0],
                   ccp->bootloader_ver[1]);

        return 0;
}
DEFINE_SHOW_ATTRIBUTE(bootloader);

static void ccp_debugfs_init(struct ccp_device *ccp)
{
        char name[32];
        int ret;

        scnprintf(name, sizeof(name), "corsaircpro-%s", dev_name(&ccp->hdev->dev));
        ccp->debugfs = debugfs_create_dir(name, NULL);

        ret = get_fw_version(ccp);
        if (!ret)
                debugfs_create_file("firmware_version", 0444,
                                    ccp->debugfs, ccp, &firmware_fops);

        ret = get_bl_version(ccp);
        if (!ret)
                debugfs_create_file("bootloader_version", 0444,
                                    ccp->debugfs, ccp, &bootloader_fops);
}

static int ccp_probe(struct hid_device *hdev, const struct hid_device_id *id)
{
        struct ccp_device *ccp;
        int ret;

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

        ccp->cmd_buffer = devm_kmalloc(&hdev->dev, OUT_BUFFER_SIZE, GFP_KERNEL);
        if (!ccp->cmd_buffer)
                return -ENOMEM;

        ccp->buffer = devm_kmalloc(&hdev->dev, IN_BUFFER_SIZE, GFP_KERNEL);
        if (!ccp->buffer)
                return -ENOMEM;

        ret = hid_parse(hdev);
        if (ret)
                return ret;

        ret = hid_hw_start(hdev, HID_CONNECT_HIDRAW);
        if (ret)
                return ret;

        ret = hid_hw_open(hdev);
        if (ret)
                goto out_hw_stop;

        ccp->hdev = hdev;
        hid_set_drvdata(hdev, ccp);

        mutex_init(&ccp->mutex);
        spin_lock_init(&ccp->wait_input_report_lock);
        init_completion(&ccp->wait_input_report);

        hid_device_io_start(hdev);

        /* temp and fan connection status only updates when device is powered on */
        ret = get_temp_cnct(ccp);
        if (ret)
                goto out_hw_close;

        ret = get_fan_cnct(ccp);
        if (ret)
                goto out_hw_close;

        ccp_debugfs_init(ccp);

        ccp->hwmon_dev = hwmon_device_register_with_info(&hdev->dev, "corsaircpro",
                                                         ccp, &ccp_chip_info, NULL);
        if (IS_ERR(ccp->hwmon_dev)) {
                ret = PTR_ERR(ccp->hwmon_dev);
                goto out_hw_close;
        }

        return 0;

out_hw_close:
        hid_hw_close(hdev);
out_hw_stop:
        hid_hw_stop(hdev);
        return ret;
}

static void ccp_remove(struct hid_device *hdev)
{
        struct ccp_device *ccp = hid_get_drvdata(hdev);

        debugfs_remove_recursive(ccp->debugfs);
        hwmon_device_unregister(ccp->hwmon_dev);
        hid_hw_close(hdev);
        hid_hw_stop(hdev);
}

static const struct hid_device_id ccp_devices[] = {
        { HID_USB_DEVICE(USB_VENDOR_ID_CORSAIR, USB_PRODUCT_ID_CORSAIR_COMMANDERPRO) },
        { HID_USB_DEVICE(USB_VENDOR_ID_CORSAIR, USB_PRODUCT_ID_CORSAIR_1000D) },
        { }
};

static struct hid_driver ccp_driver = {
        .name = "corsair-cpro",
        .id_table = ccp_devices,
        .probe = ccp_probe,
        .remove = ccp_remove,
        .raw_event = ccp_raw_event,
};

MODULE_DEVICE_TABLE(hid, ccp_devices);
MODULE_DESCRIPTION("Corsair Commander Pro controller driver");
MODULE_LICENSE("GPL");

static int __init ccp_init(void)
{
        return hid_register_driver(&ccp_driver);
}

static void __exit ccp_exit(void)
{
        hid_unregister_driver(&ccp_driver);
}

/*
 * When compiling this driver as built-in, hwmon initcalls will get called before the
 * hid driver and this driver would fail to register. late_initcall solves this.
 */
late_initcall(ccp_init);
module_exit(ccp_exit);