Linux ms3020串口驱动移植

// SPDX-License-Identifier: GPL-2.0
/*
 * Macrosilicon MS3020 USB to serial adaptor driver
 *
 * Original driver for LINUX 2.2.x
 *
 */

#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/tty.h>
#include <linux/tty_driver.h>
#include <linux/tty_flip.h>
#include <linux/serial.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/spinlock.h>
#include <linux/uaccess.h>
#include <linux/usb.h>
#include <linux/usb/serial.h>
#include <asm/unaligned.h>

#define MS3020_VENDOR_ID (0x345f)
#define MS3020_PRODUCT_ID (0x3020)

#define SET_LINE_REQUEST_TYPE                (0x21)
#define SET_LINE_REQUEST                    (0x20)
#define GET_LINE_REQUEST_TYPE                (0xa1)
#define GET_LINE_REQUEST                    (0x21)

#define SET_CONTROL_REQUEST_TYPE        (0x21)
#define SET_CONTROL_REQUEST                    (0x22)
#define CONTROL_DTR                                (0x01)
#define CONTROL_RTS                                (0x02)

#define BREAK_REQUEST_TYPE                    (0x21)
#define BREAK_REQUEST                            (0x23)
#define BREAK_ON                                (0xffff)
#define BREAK_OFF                                (0x0000)

#define VENDOR_WRITE_REQUEST_TYPE        (0x40)
#define VENDOR_WRITE_REQUEST                (0x80)
#define VENDOR_READ_REQUEST_TYPE        (0xc0)
#define VENDOR_READ_REQUEST                    (0x81)

#define UART_STATE_INDEX                    (8)
#define UART_STATE_MSR_MASK                    (0x8b)
#define UART_STATE_TRANSIENT_MASK        (0x74)
#define UART_DCD                                (0x01)
#define UART_DSR                                (0x02)
#define UART_BREAK_ERROR                    (0x04)
#define UART_RING                                (0x08)
#define UART_FRAME_ERROR                    (0x10)
#define UART_PARITY_ERROR                    (0x20)
#define UART_OVERRUN_ERROR                    (0x40)
#define UART_CTS                                (0x80)

#define MS3020_FLOWCTRL_MASK                    (0xf0)
#define MS3020_DEF_FLOWCTRL_REG                    (0x0a)
#define MS3020_DEF_FLOWCTRL_MASK            (0x1c)
#define MS3020_DEF_FLOWCTRL_NONE            (0x1c)
#define MS3020_DEF_FLOWCTRL_RTS_CTS            (0x18)
#define MS3020_DEF_FLOWCTRL_XON_XOFF        (0x0c)

static const struct usb_device_id id_table[] = {
        { USB_DEVICE_INTERFACE_CLASS(MS3020_VENDOR_ID, MS3020_PRODUCT_ID, 0xff) },
        { }
};

MODULE_DEVICE_TABLE(usb, id_table);

static void ms3020_set_break(struct usb_serial_port *port, bool enable);

enum ms3020_type {
        TYPE_DEF,
        TYPE_COUNT
};

struct ms3020_type_data {
        const char *name;
        speed_t max_baud_rate;
};

struct ms3020_serial_private {
        const struct ms3020_type_data *type;
};

struct ms3020_private {
        spinlock_t lock;
        u8 line_control;
        u8 line_status;

        u8 line_settings[7];
};

static const struct ms3020_type_data ms3020_type_data[TYPE_COUNT] = {
        [TYPE_DEF] = {
                .name                        = "DEF",
                .max_baud_rate                = 12000000,
        },
};

static int ms3020_vendor_read(struct usb_serial *serial, u16 value, unsigned char buf[1])
{
        struct device *dev = &serial->interface->dev;
        int ret;

        ret = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
                        VENDOR_READ_REQUEST, VENDOR_READ_REQUEST_TYPE,
                        value, 0, buf, 1, 100);
        if (ret != 1) {
                dev_err(dev, "%s failed to read [%04x]: %d\n", __func__, value, ret);
                if (ret >= 0)
                        ret = -EIO;

                return ret;
        }

        dev_dbg(dev, "%s [%04x] = %02x\n", __func__, value, buf[0]);

        return 0;
}

static int ms3020_vendor_write(struct usb_serial *serial, u16 value, u16 index)
{
        struct device *dev = &serial->interface->dev;
        int ret;

        dev_dbg(dev, "%s [%04x] = %02x\n", __func__, value, index);
        ret = usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
                        VENDOR_WRITE_REQUEST, VENDOR_WRITE_REQUEST_TYPE,
                        value, index, NULL, 0, 100);
        if (ret) {
                dev_err(dev, "%s failed to write [%04x]: %d\n", __func__, value, ret);
                return ret;
        }

        return 0;
}

static int ms3020_update_reg(struct usb_serial *serial, u8 reg, u8 mask, u8 val)
{
        int ret = 0;
        u8 *buf;

        buf = kmalloc(1, GFP_KERNEL);
        if (!buf)
                return -ENOMEM;

        ret = ms3020_vendor_read(serial, reg, buf);

        if (ret)
                goto out_free;

        *buf &= ~mask;
        *buf |= val & mask;

        ret = ms3020_vendor_write(serial, reg, *buf);
out_free:
        kfree(buf);

        return ret;
}

static int ms3020_probe(struct usb_serial *serial,
                                        const struct usb_device_id *id)
{
        usb_set_serial_data(serial, (void *)id->driver_info);

        return 0;
}

static int ms3020_startup(struct usb_serial *serial)
{
        struct ms3020_serial_private *spriv;
        unsigned char num_ports = serial->num_ports;
        enum ms3020_type type;

        if (serial->num_bulk_in < num_ports || serial->num_bulk_out < num_ports ||
                        serial->num_interrupt_in < num_ports) {
                dev_err(&serial->interface->dev, " error num_ports");
                return -ENODEV;
        }

        type = TYPE_DEF;
        spriv = kzalloc(sizeof(*spriv), GFP_KERNEL);
        if (!spriv)
                return -ENOMEM;

        spriv->type = &ms3020_type_data[type];

        usb_set_serial_data(serial, spriv);

        return 0;
}

static void ms3020_release(struct usb_serial *serial)
{
        struct ms3020_serial_private *spriv = usb_get_serial_data(serial);

        kfree(spriv);
}

static int ms3020_port_probe(struct usb_serial_port *port)
{
        struct ms3020_private *priv;

        priv = kzalloc(sizeof(*priv), GFP_KERNEL);
        if (!priv)
                return -ENOMEM;

        spin_lock_init(&priv->lock);

        usb_set_serial_port_data(port, priv);

        port->port.drain_delay = 256;

        return 0;
}

static int ms3020_port_remove(struct usb_serial_port *port)
{
        struct ms3020_private *priv = usb_get_serial_port_data(port);

        kfree(priv);

        return 0;
}

static int ms3020_set_control_lines(struct usb_serial_port *port, u8 value)
{
        struct usb_device *dev = port->serial->dev;
        int retval;

        dev_dbg(&port->dev, "%s %02x\n", __func__, value);

        retval = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
                                 SET_CONTROL_REQUEST, SET_CONTROL_REQUEST_TYPE,
                                 value, 0, NULL, 0, 100);
        if (retval)
                dev_err(&port->dev, "%s failed: %d\n", __func__, retval);

        return retval;
}

static speed_t _ms3020_encode_baud_rate(unsigned char buf[4],
                                                                speed_t baud)
{
        put_unaligned_le32(baud, buf);

        return baud;
}

static void ms3020_encode_baud_rate(struct tty_struct *tty,
                                        struct usb_serial_port *port, u8 buf[4])
{
        struct usb_serial *serial = port->serial;
        struct ms3020_serial_private *spriv = usb_get_serial_data(serial);
        speed_t baud;

        baud = tty_get_baud_rate(tty);
        dev_dbg(&port->dev, "baud requested = %u\n", baud);

        if (!baud)
                return;

        if (spriv->type->max_baud_rate)
                baud = min_t(speed_t, baud, spriv->type->max_baud_rate);


        _ms3020_encode_baud_rate(buf, baud);

        /* Save resulting baud rate */
        tty_encode_baud_rate(tty, baud, baud);
        dev_dbg(&port->dev, "baud set = %u\n", baud);

}

static int ms3020_get_line_request(struct usb_serial_port *port,
                                                        unsigned char buf[7])
{
        struct usb_device *udev = port->serial->dev;
        int ret;

        ret = usb_control_msg(udev, usb_rcvctrlpipe(udev, 0),
                                GET_LINE_REQUEST, GET_LINE_REQUEST_TYPE,
                                0, 0, buf, 7, 100);
        if (ret != 7) {
                dev_err(&port->dev, "%s - failed: %d\n", __func__, ret);

                if (ret >= 0)
                        ret = -EIO;

                return ret;
        }

        dev_dbg(&port->dev, "%s - %7ph\n", __func__, buf);

        return 0;
}

static int ms3020_set_line_request(struct usb_serial_port *port,
                                                        unsigned char buf[7])
{
        struct usb_device *udev = port->serial->dev;
        int ret;

        ret = usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
                                SET_LINE_REQUEST, SET_LINE_REQUEST_TYPE,
                                0, 0, buf, 7, 100);
        if (ret < 0) {
                dev_err(&port->dev, "%s - failed: %d\n", __func__, ret);
                return ret;
        }

        dev_dbg(&port->dev, "%s - %7ph\n", __func__, buf);

        return 0;
}

static bool ms3020_termios_change(struct ktermios *a, struct ktermios *b)
{
        bool ixon_change;

        ixon_change = ((a->c_iflag ^ b->c_iflag) & (IXON | IXANY)) ||
                        a->c_cc[VSTART] != b->c_cc[VSTART] ||
                        a->c_cc[VSTOP] != b->c_cc[VSTOP];

        return tty_termios_hw_change(a, b) || ixon_change;
}

static bool ms3020_enable_xonxoff(struct tty_struct *tty, const struct ms3020_type_data *type)
{
        if (!I_IXON(tty) || I_IXANY(tty))
                return false;

        return true;
}

static void ms3020_set_termios(struct tty_struct *tty,
                struct usb_serial_port *port, struct ktermios *old_termios)
{
        struct usb_serial *serial = port->serial;
        struct ms3020_serial_private *spriv = usb_get_serial_data(serial);
        struct ms3020_private *priv = usb_get_serial_port_data(port);
        unsigned long flags;
        unsigned char *buf;
        int ret;
        u8 control;

        if (old_termios && !ms3020_termios_change(&tty->termios, old_termios))
                return;

        buf = kzalloc(7, GFP_KERNEL);
        if (!buf) {
                if (old_termios)
                        tty->termios = *old_termios;
                return;
        }

        ms3020_get_line_request(port, buf);

        switch (C_CSIZE(tty)) {
        case CS5:
                buf[6] = 5;
                break;
        case CS6:
                buf[6] = 6;
                break;
        case CS7:
                buf[6] = 7;
                break;
        default:
        case CS8:
                buf[6] = 8;
        }
        dev_dbg(&port->dev, "data bits = %d\n", buf[6]);

        ms3020_encode_baud_rate(tty, port, &buf[0]);

        if (C_PARENB(tty)) {
                if (C_PARODD(tty)) {
                        if (C_CMSPAR(tty)) {
                                buf[5] = 3;
                                dev_dbg(&port->dev, "parity = mark\n");
                        } else {
                                buf[5] = 1;
                                dev_dbg(&port->dev, "parity = odd\n");
                        }
                } else {
                        if (C_CMSPAR(tty)) {
                                buf[5] = 4;
                                dev_dbg(&port->dev, "parity = space\n");
                        } else {
                                buf[5] = 2;
                                dev_dbg(&port->dev, "parity = even\n");
                        }
                }
        } else {
                buf[5] = 0;
                dev_dbg(&port->dev, "parity = none\n");
        }

        if (C_CSTOPB(tty)) {
                if (C_CSIZE(tty) == CS5) {
                        buf[4] = 1;
                        dev_dbg(&port->dev, "stop bits = 1.5\n");
                } else {
                        buf[4] = 2;
                        dev_dbg(&port->dev, "stop bits = 2\n");
                }
        } else {
                buf[4] = 0;
                dev_dbg(&port->dev, "stop bits = 1\n");
        }

        if (!old_termios || memcmp(buf, priv->line_settings, 7)) {
                ret = ms3020_set_line_request(port, buf);
                if (!ret)
                        memcpy(priv->line_settings, buf, 7);
        }

        spin_lock_irqsave(&priv->lock, flags);
        control = priv->line_control;
        if (C_BAUD(tty) == B0)
                priv->line_control &= ~(CONTROL_DTR | CONTROL_RTS);
        else if (old_termios && (old_termios->c_cflag & CBAUD) == B0)
                priv->line_control |= (CONTROL_DTR | CONTROL_RTS);
        if (control != priv->line_control) {
                control = priv->line_control;
                spin_unlock_irqrestore(&priv->lock, flags);
                ms3020_set_control_lines(port, control);
        } else {
                spin_unlock_irqrestore(&priv->lock, flags);
        }

        if (C_CRTSCTS(tty)) {
            if (spriv->type == &ms3020_type_data[TYPE_DEF]) {
                        ms3020_update_reg(serial, MS3020_DEF_FLOWCTRL_REG,
                                        MS3020_DEF_FLOWCTRL_MASK,
                                        MS3020_DEF_FLOWCTRL_RTS_CTS);
                }
        } else if (ms3020_enable_xonxoff(tty, spriv->type)) {
                if (spriv->type == &ms3020_type_data[TYPE_DEF]) {
                        ms3020_update_reg(serial, MS3020_DEF_FLOWCTRL_REG,
                                        MS3020_DEF_FLOWCTRL_MASK,
                                        MS3020_DEF_FLOWCTRL_XON_XOFF);
                }
        } else {
                if (spriv->type == &ms3020_type_data[TYPE_DEF]) {
                        ms3020_update_reg(serial, MS3020_DEF_FLOWCTRL_REG,
                                        MS3020_DEF_FLOWCTRL_MASK,
                                        MS3020_DEF_FLOWCTRL_NONE);
                }
        }

        kfree(buf);
}

static void ms3020_dtr_rts(struct usb_serial_port *port, int on)
{
        struct ms3020_private *priv = usb_get_serial_port_data(port);
        unsigned long flags;
        u8 control;

        spin_lock_irqsave(&priv->lock, flags);
        if (on)
                priv->line_control |= (CONTROL_DTR | CONTROL_RTS);
        else
                priv->line_control &= ~(CONTROL_DTR | CONTROL_RTS);
        control = priv->line_control;
        spin_unlock_irqrestore(&priv->lock, flags);

        ms3020_set_control_lines(port, control);
}

static void ms3020_close(struct usb_serial_port *port)
{
        usb_serial_generic_close(port);
        usb_kill_urb(port->interrupt_in_urb);
        ms3020_set_break(port, false);
}

static int ms3020_open(struct tty_struct *tty, struct usb_serial_port *port)
{
        int result;

        /* Setup termios */
        if (tty)
                ms3020_set_termios(tty, port, NULL);

        result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
        if (result) {
                dev_err(&port->dev, "failed to submit interrupt urb: %d\n",
                        result);
                return result;
        }

        result = usb_serial_generic_open(tty, port);
        if (result) {
                usb_kill_urb(port->interrupt_in_urb);
                return result;
        }

        return 0;
}

static int ms3020_tiocmset(struct tty_struct *tty,
                           unsigned int set, unsigned int clear)
{
        struct usb_serial_port *port = tty->driver_data;
        struct ms3020_private *priv = usb_get_serial_port_data(port);
        unsigned long flags;
        u8 control;
        int ret;

        spin_lock_irqsave(&priv->lock, flags);
        if (set & TIOCM_RTS)
                priv->line_control |= CONTROL_RTS;
        if (set & TIOCM_DTR)
                priv->line_control |= CONTROL_DTR;
        if (clear & TIOCM_RTS)
                priv->line_control &= ~CONTROL_RTS;
        if (clear & TIOCM_DTR)
                priv->line_control &= ~CONTROL_DTR;
        control = priv->line_control;
        spin_unlock_irqrestore(&priv->lock, flags);

        ret = ms3020_set_control_lines(port, control);
        if (ret)
                return usb_translate_errors(ret);

        return 0;
}

static int ms3020_tiocmget(struct tty_struct *tty)
{
        struct usb_serial_port *port = tty->driver_data;
        struct ms3020_private *priv = usb_get_serial_port_data(port);
        unsigned long flags;
        unsigned int mcr;
        unsigned int status;
        unsigned int result;

        spin_lock_irqsave(&priv->lock, flags);
        mcr = priv->line_control;
        status = priv->line_status;
        spin_unlock_irqrestore(&priv->lock, flags);

        result = ((mcr & CONTROL_DTR)                ? TIOCM_DTR : 0)
                  | ((mcr & CONTROL_RTS)        ? TIOCM_RTS : 0)
                  | ((status & UART_CTS)        ? TIOCM_CTS : 0)
                  | ((status & UART_DSR)        ? TIOCM_DSR : 0)
                  | ((status & UART_RING)        ? TIOCM_RI  : 0)
                  | ((status & UART_DCD)        ? TIOCM_CD  : 0);

        dev_dbg(&port->dev, "%s - result = %x\n", __func__, result);

        return result;
}

static int ms3020_carrier_raised(struct usb_serial_port *port)
{
        struct ms3020_private *priv = usb_get_serial_port_data(port);

        if (priv->line_status & UART_DCD)
                return 1;

        return 0;
}

static int ms3020_ioctl(struct tty_struct *tty,
                        unsigned int cmd, unsigned long arg)
{
        struct serial_struct ser;
        struct usb_serial_port *port = tty->driver_data;

        switch (cmd) {
        case TIOCGSERIAL:
                memset(&ser, 0, sizeof ser);
                ser.type = PORT_16654;
                ser.line = port->minor;
                ser.port = port->port_number;
                ser.baud_base = 460800;

                if (copy_to_user((void __user *)arg, &ser, sizeof ser))
                        return -EFAULT;

                return 0;
        default:
                break;
        }

        return -ENOIOCTLCMD;
}

static void ms3020_set_break(struct usb_serial_port *port, bool enable)
{
        struct usb_serial *serial = port->serial;
        u16 state;
        int result;

        if (enable)
                state = BREAK_ON;
        else
                state = BREAK_OFF;

        dev_dbg(&port->dev, "%s turning break %s\n", __func__,
                        state == BREAK_OFF ? "off" : "on");

        result = usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
                                 BREAK_REQUEST, BREAK_REQUEST_TYPE, state,
                                 0, NULL, 0, 100);
        if (result)
                dev_err(&port->dev, "error sending break = %d\n", result);
}

static void ms3020_break_ctl(struct tty_struct *tty, int state)
{
        struct usb_serial_port *port = tty->driver_data;

        ms3020_set_break(port, state);
}

static void ms3020_update_line_status(struct usb_serial_port *port,
                                      unsigned char *data,
                                      unsigned int actual_length)
{
        struct ms3020_private *priv = usb_get_serial_port_data(port);
        struct tty_struct *tty;
        unsigned long flags;
        unsigned int status_idx = UART_STATE_INDEX;
        u8 status;
        u8 delta;

        if (actual_length < status_idx + 1)
                return;

        status = data[status_idx];

        /* Save off the uart status for others to look at */
        spin_lock_irqsave(&priv->lock, flags);
        delta = priv->line_status ^ status;
        priv->line_status = status;
        spin_unlock_irqrestore(&priv->lock, flags);

        if (status & UART_BREAK_ERROR)
                usb_serial_handle_break(port);

        if (delta & UART_STATE_MSR_MASK) {
                if (delta & UART_CTS)
                        port->icount.cts++;
                if (delta & UART_DSR)
                        port->icount.dsr++;
                if (delta & UART_RING)
                        port->icount.rng++;
                if (delta & UART_DCD) {
                        port->icount.dcd++;
                        tty = tty_port_tty_get(&port->port);
                        if (tty) {
                                usb_serial_handle_dcd_change(port, tty,
                                                        status & UART_DCD);
                                tty_kref_put(tty);
                        }
                }

                wake_up_interruptible(&port->port.delta_msr_wait);
        }
}

static void ms3020_read_int_callback(struct urb *urb)
{
        struct usb_serial_port *port =  urb->context;
        unsigned char *data = urb->transfer_buffer;
        unsigned int actual_length = urb->actual_length;
        int status = urb->status;
        int retval;

        switch (status) {
        case 0:
                /* success */
                break;
        case -ECONNRESET:
        case -ENOENT:
        case -ESHUTDOWN:
                /* this urb is terminated, clean up */
                dev_dbg(&port->dev, "%s urb shutting down with status: %d\n",
                        __func__, status);
                return;
        default:
                dev_dbg(&port->dev, "%s nonzero urb status received: %d\n",
                        __func__, status);
                goto exit;
        }

        usb_serial_debug_data(&port->dev, __func__,
                              urb->actual_length, urb->transfer_buffer);

        ms3020_update_line_status(port, data, actual_length);

exit:
        retval = usb_submit_urb(urb, GFP_ATOMIC);
        if (retval) {
                dev_err(&port->dev,
                        "%s usb_submit_urb failed with result %d\n",
                        __func__, retval);
        }
}

static void ms3020_process_read_urb(struct urb *urb)
{
        struct usb_serial_port *port = urb->context;
        struct ms3020_private *priv = usb_get_serial_port_data(port);
        unsigned char *data = urb->transfer_buffer;
        char tty_flag = TTY_NORMAL;
        unsigned long flags;
        u8 line_status;
        int i;
        

        /* update line status */
        spin_lock_irqsave(&priv->lock, flags);
        line_status = priv->line_status;
        priv->line_status &= ~UART_STATE_TRANSIENT_MASK;
        spin_unlock_irqrestore(&priv->lock, flags);

        if (!urb->actual_length)
                return;

        /*
         * Break takes precedence over parity, which takes precedence over
         * framing errors.
         */
        if (line_status & UART_BREAK_ERROR)
                tty_flag = TTY_BREAK;
        else if (line_status & UART_PARITY_ERROR)
                tty_flag = TTY_PARITY;
        else if (line_status & UART_FRAME_ERROR)
                tty_flag = TTY_FRAME;

        if (tty_flag != TTY_NORMAL)
                dev_dbg(&port->dev, "%s tty_flag = %d\n", __func__,
                                                                tty_flag);
        /* overrun is special, not associated with a char */
        if (line_status & UART_OVERRUN_ERROR)
                tty_insert_flip_char(&port->port, 0, TTY_OVERRUN);

        if (port->port.console && port->sysrq) {
                for (i = 0; i < urb->actual_length; ++i)
                        if (!usb_serial_handle_sysrq_char(port, data[i]))
                                tty_insert_flip_char(&port->port, data[i],
                                                tty_flag);
        } else {
                tty_insert_flip_string_fixed_flag(&port->port, data, tty_flag,
                                                        urb->actual_length);
        }

        tty_flip_buffer_push(&port->port);
}

static struct usb_serial_driver ms3020_device = {
        .driver = {
                .owner =        THIS_MODULE,
                .name =                "ms3020",
        },
        .id_table =                id_table,
        .num_ports =                1,
        .bulk_in_size =                256,
        .bulk_out_size =        256,
        .open =                        ms3020_open,
        .close =                ms3020_close,
        .dtr_rts =                ms3020_dtr_rts,
        .carrier_raised =        ms3020_carrier_raised,
        .ioctl =                ms3020_ioctl,
        .break_ctl =                ms3020_break_ctl,
        .set_termios =                ms3020_set_termios,
        .tiocmget =                ms3020_tiocmget,
        .tiocmset =                ms3020_tiocmset,
        .tiocmiwait =                usb_serial_generic_tiocmiwait,
        .process_read_urb =        ms3020_process_read_urb,
        .read_int_callback =        ms3020_read_int_callback,
        .throttle = usb_serial_generic_throttle,
        .unthrottle = usb_serial_generic_unthrottle,
        .probe =                ms3020_probe,
        .attach =                ms3020_startup,
        .release =                ms3020_release,
        .port_probe =                ms3020_port_probe,
        .port_remove =                ms3020_port_remove,
};

static struct usb_serial_driver * const serial_drivers[] = {
        &ms3020_device, NULL
};

module_usb_serial_driver(serial_drivers, id_table);

MODULE_DESCRIPTION("MS3020 USB to serial adaptor driver");
MODULE_LICENSE("GPL");