drivers/usb/serial/ch341.c

   1 /*
   2  * Copyright 2007, Frank A Kingswood <frank@kingswood-consulting.co.uk>
   3  * Copyright 2007, Werner Cornelius <werner@cornelius-consult.de>
   4  * Copyright 2009, Boris Hajduk <boris@hajduk.org>
   5  *
   6  * ch341.c implements a serial port driver for the Winchiphead CH341.
   7  *
   8  * The CH341 device can be used to implement an RS232 asynchronous
   9  * serial port, an IEEE-1284 parallel printer port or a memory-like
  10  * interface. In all cases the CH341 supports an I2C interface as well.
  11  * This driver only supports the asynchronous serial interface.
  12  *
  13  * This program is free software; you can redistribute it and/or
  14  * modify it under the terms of the GNU General Public License version
  15  * 2 as published by the Free Software Foundation.
  16  */
  17
  18 #include <linux/kernel.h>
  19 #include <linux/tty.h>
  20 #include <linux/module.h>
  21 #include <linux/slab.h>
  22 #include <linux/usb.h>
  23 #include <linux/usb/serial.h>
  24 #include <linux/serial.h>
  25 #include <asm/unaligned.h>
  26
  27 #define DEFAULT_BAUD_RATE 9600
  28 #define DEFAULT_TIMEOUT   1000
  29
  30 /* flags for IO-Bits */
  31 #define CH341_BIT_RTS (1 << 6)
  32 #define CH341_BIT_DTR (1 << 5)
  33
  34 /******************************/
  35 /* interrupt pipe definitions */
  36 /******************************/
  37 /* always 4 interrupt bytes */
  38 /* first irq byte normally 0x08 */
  39 /* second irq byte base 0x7d + below */
  40 /* third irq byte base 0x94 + below */
  41 /* fourth irq byte normally 0xee */
  42
  43 /* second interrupt byte */
  44 #define CH341_MULT_STAT 0x04 /* multiple status since last interrupt event */
  45
  46 /* status returned in third interrupt answer byte, inverted in data
  47    from irq */
  48 #define CH341_BIT_CTS 0x01
  49 #define CH341_BIT_DSR 0x02
  50 #define CH341_BIT_RI  0x04
  51 #define CH341_BIT_DCD 0x08
  52 #define CH341_BITS_MODEM_STAT 0x0f /* all bits */
  53
  54 /*******************************/
  55 /* baudrate calculation factor */
  56 /*******************************/
  57 #define CH341_BAUDBASE_FACTOR 1532620800
  58 #define CH341_BAUDBASE_DIVMAX 3
  59
  60 /* Break support - the information used to implement this was gleaned from
  61  * the Net/FreeBSD uchcom.c driver by Takanori Watanabe.  Domo arigato.
  62  */
  63
  64 #define CH341_REQ_READ_VERSION 0x5F
  65 #define CH341_REQ_WRITE_REG    0x9A
  66 #define CH341_REQ_READ_REG     0x95
  67 #define CH341_REQ_SERIAL_INIT  0xA1
  68 #define CH341_REQ_MODEM_CTRL   0xA4
  69
  70 #define CH341_REG_BREAK        0x05
  71 #define CH341_REG_LCR          0x18
  72 #define CH341_NBREAK_BITS      0x01
  73
  74 #define CH341_LCR_ENABLE_RX    0x80
  75 #define CH341_LCR_ENABLE_TX    0x40
  76 #define CH341_LCR_MARK_SPACE   0x20
  77 #define CH341_LCR_PAR_EVEN     0x10
  78 #define CH341_LCR_ENABLE_PAR   0x08
  79 #define CH341_LCR_STOP_BITS_2  0x04
  80 #define CH341_LCR_CS8          0x03
  81 #define CH341_LCR_CS7          0x02
  82 #define CH341_LCR_CS6          0x01
  83 #define CH341_LCR_CS5          0x00
  84
  85 static const struct usb_device_id id_table[] = {
  86         { USB_DEVICE(0x4348, 0x5523) },
  87         { USB_DEVICE(0x1a86, 0x7523) },
  88         { USB_DEVICE(0x1a86, 0x5523) },
  89         { },
  90 };
  91 MODULE_DEVICE_TABLE(usb, id_table);
  92
  93 struct ch341_private {
  94         spinlock_t lock; /* access lock */
  95         unsigned baud_rate; /* set baud rate */
  96         u8 line_control; /* set line control value RTS/DTR */
  97         u8 line_status; /* active status of modem control inputs */
  98         u8 lcr;
  99 };
 100
 101 static void ch341_set_termios(struct tty_struct *tty,
 102                               struct usb_serial_port *port,
 103                               struct ktermios *old_termios);
 104
 105 static int ch341_control_out(struct usb_device *dev, u8 request,
 106                              u16 value, u16 index)
 107 {
 108         int r;
 109
 110         dev_dbg(&dev->dev, "ch341_control_out(%02x,%02x,%04x,%04x)\n",
 111                 USB_DIR_OUT|0x40, (int)request, (int)value, (int)index);
 112
 113         r = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), request,
 114                             USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT,
 115                             value, index, NULL, 0, DEFAULT_TIMEOUT);
 116         if (r < 0)
 117                 dev_err(&dev->dev, "failed to send control message: %d\n", r);
 118
 119         return r;
 120 }
 121
 122 static int ch341_control_in(struct usb_device *dev,
 123                             u8 request, u16 value, u16 index,
 124                             char *buf, unsigned bufsize)
 125 {
 126         int r;
 127
 128         dev_dbg(&dev->dev, "ch341_control_in(%02x,%02x,%04x,%04x,%p,%u)\n",
 129                 USB_DIR_IN|0x40, (int)request, (int)value, (int)index, buf,
 130                 (int)bufsize);
 131
 132         r = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), request,
 133                             USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
 134                             value, index, buf, bufsize, DEFAULT_TIMEOUT);
 135         if (r < bufsize) {
 136                 if (r >= 0) {
 137                         dev_err(&dev->dev,
 138                                 "short control message received (%d < %u)\n",
 139                                 r, bufsize);
 140                         r = -EIO;
 141                 }
 142
 143                 dev_err(&dev->dev, "failed to receive control message: %d\n",
 144                         r);
 145                 return r;
 146         }
 147
 148         return 0;
 149 }
 150
 151 static int ch341_set_baudrate_lcr(struct usb_device *dev,
 152                                   struct ch341_private *priv, u8 lcr)
 153 {
 154         short a;
 155         int r;
 156         unsigned long factor;
 157         short divisor;
 158
 159         if (!priv->baud_rate)
 160                 return -EINVAL;
 161         factor = (CH341_BAUDBASE_FACTOR / priv->baud_rate);
 162         divisor = CH341_BAUDBASE_DIVMAX;
 163
 164         while ((factor > 0xfff0) && divisor) {
 165                 factor >>= 3;
 166                 divisor--;
 167         }
 168
 169         if (factor > 0xfff0)
 170                 return -EINVAL;
 171
 172         factor = 0x10000 - factor;
 173         a = (factor & 0xff00) | divisor;
 174
 175         /*
 176          * CH341A buffers data until a full endpoint-size packet (32 bytes)
 177          * has been received unless bit 7 is set.
 178          */
 179         a |= BIT(7);
 180
 181         r = ch341_control_out(dev, CH341_REQ_WRITE_REG, 0x1312, a);
 182         if (r)
 183                 return r;
 184
 185         r = ch341_control_out(dev, CH341_REQ_WRITE_REG, 0x2518, lcr);
 186         if (r)
 187                 return r;
 188
 189         return r;
 190 }
 191
 192 static int ch341_set_handshake(struct usb_device *dev, u8 control)
 193 {
 194         return ch341_control_out(dev, CH341_REQ_MODEM_CTRL, ~control, 0);
 195 }
 196
 197 static int ch341_get_status(struct usb_device *dev, struct ch341_private *priv)
 198 {
 199         const unsigned int size = 2;
 200         char *buffer;
 201         int r;
 202         unsigned long flags;
 203
 204         buffer = kmalloc(size, GFP_KERNEL);
 205         if (!buffer)
 206                 return -ENOMEM;
 207
 208         r = ch341_control_in(dev, CH341_REQ_READ_REG, 0x0706, 0, buffer, size);
 209         if (r < 0)
 210                 goto out;
 211
 212         spin_lock_irqsave(&priv->lock, flags);
 213         priv->line_status = (~(*buffer)) & CH341_BITS_MODEM_STAT;
 214         spin_unlock_irqrestore(&priv->lock, flags);
 215
 216 out:    kfree(buffer);
 217         return r;
 218 }
 219
 220 /* -------------------------------------------------------------------------- */
 221
 222 static int ch341_configure(struct usb_device *dev, struct ch341_private *priv)
 223 {
 224         const unsigned int size = 2;
 225         char *buffer;
 226         int r;
 227
 228         buffer = kmalloc(size, GFP_KERNEL);
 229         if (!buffer)
 230                 return -ENOMEM;
 231
 232         /* expect two bytes 0x27 0x00 */
 233         r = ch341_control_in(dev, CH341_REQ_READ_VERSION, 0, 0, buffer, size);
 234         if (r < 0)
 235                 goto out;
 236         dev_dbg(&dev->dev, "Chip version: 0x%02x\n", buffer[0]);
 237
 238         r = ch341_control_out(dev, CH341_REQ_SERIAL_INIT, 0, 0);
 239         if (r < 0)
 240                 goto out;
 241
 242         /* expect two bytes 0x56 0x00 */
 243         r = ch341_control_in(dev, CH341_REQ_READ_REG, 0x2518, 0, buffer, size);
 244         if (r < 0)
 245                 goto out;
 246
 247         r = ch341_control_out(dev, CH341_REQ_WRITE_REG, 0x2518, 0x0050);
 248         if (r < 0)
 249                 goto out;
 250
 251         /* expect 0xff 0xee */
 252         r = ch341_get_status(dev, priv);
 253         if (r < 0)
 254                 goto out;
 255
 256         r = ch341_set_baudrate_lcr(dev, priv, priv->lcr);
 257         if (r < 0)
 258                 goto out;
 259
 260         r = ch341_set_handshake(dev, priv->line_control);
 261         if (r < 0)
 262                 goto out;
 263
 264         /* expect 0x9f 0xee */
 265         r = ch341_get_status(dev, priv);
 266
 267 out:    kfree(buffer);
 268         return r;
 269 }
 270
 271 static int ch341_port_probe(struct usb_serial_port *port)
 272 {
 273         struct ch341_private *priv;
 274         int r;
 275
 276         priv = kzalloc(sizeof(struct ch341_private), GFP_KERNEL);
 277         if (!priv)
 278                 return -ENOMEM;
 279
 280         spin_lock_init(&priv->lock);
 281         priv->baud_rate = DEFAULT_BAUD_RATE;
 282
 283         r = ch341_configure(port->serial->dev, priv);
 284         if (r < 0)
 285                 goto error;
 286
 287         usb_set_serial_port_data(port, priv);
 288         return 0;
 289
 290 error:  kfree(priv);
 291         return r;
 292 }
 293
 294 static int ch341_port_remove(struct usb_serial_port *port)
 295 {
 296         struct ch341_private *priv;
 297
 298         priv = usb_get_serial_port_data(port);
 299         kfree(priv);
 300
 301         return 0;
 302 }
 303
 304 static int ch341_carrier_raised(struct usb_serial_port *port)
 305 {
 306         struct ch341_private *priv = usb_get_serial_port_data(port);
 307         if (priv->line_status & CH341_BIT_DCD)
 308                 return 1;
 309         return 0;
 310 }
 311
 312 static void ch341_dtr_rts(struct usb_serial_port *port, int on)
 313 {
 314         struct ch341_private *priv = usb_get_serial_port_data(port);
 315         unsigned long flags;
 316
 317         /* drop DTR and RTS */
 318         spin_lock_irqsave(&priv->lock, flags);
 319         if (on)
 320                 priv->line_control |= CH341_BIT_RTS | CH341_BIT_DTR;
 321         else
 322                 priv->line_control &= ~(CH341_BIT_RTS | CH341_BIT_DTR);
 323         spin_unlock_irqrestore(&priv->lock, flags);
 324         ch341_set_handshake(port->serial->dev, priv->line_control);
 325 }
 326
 327 static void ch341_close(struct usb_serial_port *port)
 328 {
 329         usb_serial_generic_close(port);
 330         usb_kill_urb(port->interrupt_in_urb);
 331 }
 332
 333
 334 /* open this device, set default parameters */
 335 static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port)
 336 {
 337         struct usb_serial *serial = port->serial;
 338         struct ch341_private *priv = usb_get_serial_port_data(port);
 339         int r;
 340
 341         r = ch341_configure(serial->dev, priv);
 342         if (r)
 343                 return r;
 344
 345         if (tty)
 346                 ch341_set_termios(tty, port, NULL);
 347
 348         dev_dbg(&port->dev, "%s - submitting interrupt urb\n", __func__);
 349         r = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
 350         if (r) {
 351                 dev_err(&port->dev, "%s - failed to submit interrupt urb: %d\n",
 352                         __func__, r);
 353                 return r;
 354         }
 355
 356         r = usb_serial_generic_open(tty, port);
 357         if (r)
 358                 goto err_kill_interrupt_urb;
 359
 360         return 0;
 361
 362 err_kill_interrupt_urb:
 363         usb_kill_urb(port->interrupt_in_urb);
 364
 365         return r;
 366 }
 367
 368 /* Old_termios contains the original termios settings and
 369  * tty->termios contains the new setting to be used.
 370  */
 371 static void ch341_set_termios(struct tty_struct *tty,
 372                 struct usb_serial_port *port, struct ktermios *old_termios)
 373 {
 374         struct ch341_private *priv = usb_get_serial_port_data(port);
 375         unsigned baud_rate;
 376         unsigned long flags;
 377         unsigned char ctrl;
 378         int r;
 379
 380         /* redundant changes may cause the chip to lose bytes */
 381         if (old_termios && !tty_termios_hw_change(&tty->termios, old_termios))
 382                 return;
 383
 384         baud_rate = tty_get_baud_rate(tty);
 385
 386         ctrl = CH341_LCR_ENABLE_RX | CH341_LCR_ENABLE_TX;
 387
 388         switch (C_CSIZE(tty)) {
 389         case CS5:
 390                 ctrl |= CH341_LCR_CS5;
 391                 break;
 392         case CS6:
 393                 ctrl |= CH341_LCR_CS6;
 394                 break;
 395         case CS7:
 396                 ctrl |= CH341_LCR_CS7;
 397                 break;
 398         case CS8:
 399                 ctrl |= CH341_LCR_CS8;
 400                 break;
 401         }
 402
 403         if (C_PARENB(tty)) {
 404                 ctrl |= CH341_LCR_ENABLE_PAR;
 405                 if (C_PARODD(tty) == 0)
 406                         ctrl |= CH341_LCR_PAR_EVEN;
 407                 if (C_CMSPAR(tty))
 408                         ctrl |= CH341_LCR_MARK_SPACE;
 409         }
 410
 411         if (C_CSTOPB(tty))
 412                 ctrl |= CH341_LCR_STOP_BITS_2;
 413
 414         if (baud_rate) {
 415                 priv->baud_rate = baud_rate;
 416
 417                 r = ch341_set_baudrate_lcr(port->serial->dev, priv, ctrl);
 418                 if (r < 0 && old_termios) {
 419                         priv->baud_rate = tty_termios_baud_rate(old_termios);
 420                         tty_termios_copy_hw(&tty->termios, old_termios);
 421                 } else if (r == 0) {
 422                         priv->lcr = ctrl;
 423                 }
 424         }
 425
 426         spin_lock_irqsave(&priv->lock, flags);
 427         if (C_BAUD(tty) == B0)
 428                 priv->line_control &= ~(CH341_BIT_DTR | CH341_BIT_RTS);
 429         else if (old_termios && (old_termios->c_cflag & CBAUD) == B0)
 430                 priv->line_control |= (CH341_BIT_DTR | CH341_BIT_RTS);
 431         spin_unlock_irqrestore(&priv->lock, flags);
 432
 433         ch341_set_handshake(port->serial->dev, priv->line_control);
 434 }
 435
 436 static void ch341_break_ctl(struct tty_struct *tty, int break_state)
 437 {
 438         const uint16_t ch341_break_reg =
 439                         ((uint16_t) CH341_REG_LCR << 8) | CH341_REG_BREAK;
 440         struct usb_serial_port *port = tty->driver_data;
 441         int r;
 442         uint16_t reg_contents;
 443         uint8_t *break_reg;
 444
 445         break_reg = kmalloc(2, GFP_KERNEL);
 446         if (!break_reg)
 447                 return;
 448
 449         r = ch341_control_in(port->serial->dev, CH341_REQ_READ_REG,
 450                         ch341_break_reg, 0, break_reg, 2);
 451         if (r < 0) {
 452                 dev_err(&port->dev, "%s - USB control read error (%d)\n",
 453                                 __func__, r);
 454                 goto out;
 455         }
 456         dev_dbg(&port->dev, "%s - initial ch341 break register contents - reg1: %x, reg2: %x\n",
 457                 __func__, break_reg[0], break_reg[1]);
 458         if (break_state != 0) {
 459                 dev_dbg(&port->dev, "%s - Enter break state requested\n", __func__);
 460                 break_reg[0] &= ~CH341_NBREAK_BITS;
 461                 break_reg[1] &= ~CH341_LCR_ENABLE_TX;
 462         } else {
 463                 dev_dbg(&port->dev, "%s - Leave break state requested\n", __func__);
 464                 break_reg[0] |= CH341_NBREAK_BITS;
 465                 break_reg[1] |= CH341_LCR_ENABLE_TX;
 466         }
 467         dev_dbg(&port->dev, "%s - New ch341 break register contents - reg1: %x, reg2: %x\n",
 468                 __func__, break_reg[0], break_reg[1]);
 469         reg_contents = get_unaligned_le16(break_reg);
 470         r = ch341_control_out(port->serial->dev, CH341_REQ_WRITE_REG,
 471                         ch341_break_reg, reg_contents);
 472         if (r < 0)
 473                 dev_err(&port->dev, "%s - USB control write error (%d)\n",
 474                                 __func__, r);
 475 out:
 476         kfree(break_reg);
 477 }
 478
 479 static int ch341_tiocmset(struct tty_struct *tty,
 480                           unsigned int set, unsigned int clear)
 481 {
 482         struct usb_serial_port *port = tty->driver_data;
 483         struct ch341_private *priv = usb_get_serial_port_data(port);
 484         unsigned long flags;
 485         u8 control;
 486
 487         spin_lock_irqsave(&priv->lock, flags);
 488         if (set & TIOCM_RTS)
 489                 priv->line_control |= CH341_BIT_RTS;
 490         if (set & TIOCM_DTR)
 491                 priv->line_control |= CH341_BIT_DTR;
 492         if (clear & TIOCM_RTS)
 493                 priv->line_control &= ~CH341_BIT_RTS;
 494         if (clear & TIOCM_DTR)
 495                 priv->line_control &= ~CH341_BIT_DTR;
 496         control = priv->line_control;
 497         spin_unlock_irqrestore(&priv->lock, flags);
 498
 499         return ch341_set_handshake(port->serial->dev, control);
 500 }
 501
 502 static void ch341_update_line_status(struct usb_serial_port *port,
 503                                         unsigned char *data, size_t len)
 504 {
 505         struct ch341_private *priv = usb_get_serial_port_data(port);
 506         struct tty_struct *tty;
 507         unsigned long flags;
 508         u8 status;
 509         u8 delta;
 510
 511         if (len < 4)
 512                 return;
 513
 514         status = ~data[2] & CH341_BITS_MODEM_STAT;
 515
 516         spin_lock_irqsave(&priv->lock, flags);
 517         delta = status ^ priv->line_status;
 518         priv->line_status = status;
 519         spin_unlock_irqrestore(&priv->lock, flags);
 520
 521         if (data[1] & CH341_MULT_STAT)
 522                 dev_dbg(&port->dev, "%s - multiple status change\n", __func__);
 523
 524         if (!delta)
 525                 return;
 526
 527         if (delta & CH341_BIT_CTS)
 528                 port->icount.cts++;
 529         if (delta & CH341_BIT_DSR)
 530                 port->icount.dsr++;
 531         if (delta & CH341_BIT_RI)
 532                 port->icount.rng++;
 533         if (delta & CH341_BIT_DCD) {
 534                 port->icount.dcd++;
 535                 tty = tty_port_tty_get(&port->port);
 536                 if (tty) {
 537                         usb_serial_handle_dcd_change(port, tty,
 538                                                 status & CH341_BIT_DCD);
 539                         tty_kref_put(tty);
 540                 }
 541         }
 542
 543         wake_up_interruptible(&port->port.delta_msr_wait);
 544 }
 545
 546 static void ch341_read_int_callback(struct urb *urb)
 547 {
 548         struct usb_serial_port *port = urb->context;
 549         unsigned char *data = urb->transfer_buffer;
 550         unsigned int len = urb->actual_length;
 551         int status;
 552
 553         switch (urb->status) {
 554         case 0:
 555                 /* success */
 556                 break;
 557         case -ECONNRESET:
 558         case -ENOENT:
 559         case -ESHUTDOWN:
 560                 /* this urb is terminated, clean up */
 561                 dev_dbg(&urb->dev->dev, "%s - urb shutting down: %d\n",
 562                         __func__, urb->status);
 563                 return;
 564         default:
 565                 dev_dbg(&urb->dev->dev, "%s - nonzero urb status: %d\n",
 566                         __func__, urb->status);
 567                 goto exit;
 568         }
 569
 570         usb_serial_debug_data(&port->dev, __func__, len, data);
 571         ch341_update_line_status(port, data, len);
 572 exit:
 573         status = usb_submit_urb(urb, GFP_ATOMIC);
 574         if (status) {
 575                 dev_err(&urb->dev->dev, "%s - usb_submit_urb failed: %d\n",
 576                         __func__, status);
 577         }
 578 }
 579
 580 static int ch341_tiocmget(struct tty_struct *tty)
 581 {
 582         struct usb_serial_port *port = tty->driver_data;
 583         struct ch341_private *priv = usb_get_serial_port_data(port);
 584         unsigned long flags;
 585         u8 mcr;
 586         u8 status;
 587         unsigned int result;
 588
 589         spin_lock_irqsave(&priv->lock, flags);
 590         mcr = priv->line_control;
 591         status = priv->line_status;
 592         spin_unlock_irqrestore(&priv->lock, flags);
 593
 594         result = ((mcr & CH341_BIT_DTR)         ? TIOCM_DTR : 0)
 595                   | ((mcr & CH341_BIT_RTS)      ? TIOCM_RTS : 0)
 596                   | ((status & CH341_BIT_CTS)   ? TIOCM_CTS : 0)
 597                   | ((status & CH341_BIT_DSR)   ? TIOCM_DSR : 0)
 598                   | ((status & CH341_BIT_RI)    ? TIOCM_RI  : 0)
 599                   | ((status & CH341_BIT_DCD)   ? TIOCM_CD  : 0);
 600
 601         dev_dbg(&port->dev, "%s - result = %x\n", __func__, result);
 602
 603         return result;
 604 }
 605
 606 static int ch341_reset_resume(struct usb_serial *serial)
 607 {
 608         struct usb_serial_port *port = serial->port[0];
 609         struct ch341_private *priv = usb_get_serial_port_data(port);
 610         int ret;
 611
 612         /* reconfigure ch341 serial port after bus-reset */
 613         ch341_configure(serial->dev, priv);
 614
 615         if (tty_port_initialized(&port->port)) {
 616                 ret = usb_submit_urb(port->interrupt_in_urb, GFP_NOIO);
 617                 if (ret) {
 618                         dev_err(&port->dev, "failed to submit interrupt urb: %d\n",
 619                                 ret);
 620                         return ret;
 621                 }
 622         }
 623
 624         return usb_serial_generic_resume(serial);
 625 }
 626
 627 static struct usb_serial_driver ch341_device = {
 628         .driver = {
 629                 .owner  = THIS_MODULE,
 630                 .name   = "ch341-uart",
 631         },
 632         .id_table          = id_table,
 633         .num_ports         = 1,
 634         .open              = ch341_open,
 635         .dtr_rts           = ch341_dtr_rts,
 636         .carrier_raised    = ch341_carrier_raised,
 637         .close             = ch341_close,
 638         .set_termios       = ch341_set_termios,
 639         .break_ctl         = ch341_break_ctl,
 640         .tiocmget          = ch341_tiocmget,
 641         .tiocmset          = ch341_tiocmset,
 642         .tiocmiwait        = usb_serial_generic_tiocmiwait,
 643         .read_int_callback = ch341_read_int_callback,
 644         .port_probe        = ch341_port_probe,
 645         .port_remove       = ch341_port_remove,
 646         .reset_resume      = ch341_reset_resume,
 647 };
 648
 649 static struct usb_serial_driver * const serial_drivers[] = {
 650         &ch341_device, NULL
 651 };
 652
 653 module_usb_serial_driver(serial_drivers, id_table);
 654
 655 MODULE_LICENSE("GPL");