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/init.h>
  20 #include <linux/tty.h>
  21 #include <linux/module.h>
  22 #include <linux/slab.h>
  23 #include <linux/usb.h>
  24 #include <linux/usb/serial.h>
  25 #include <linux/serial.h>
  26 #include <asm/unaligned.h>
  27
  28 #define DEFAULT_BAUD_RATE 9600
  29 #define DEFAULT_TIMEOUT   1000
  30
  31 /* flags for IO-Bits */
  32 #define CH341_BIT_RTS (1 << 6)
  33 #define CH341_BIT_DTR (1 << 5)
  34
  35 /******************************/
  36 /* interrupt pipe definitions */
  37 /******************************/
  38 /* always 4 interrupt bytes */
  39 /* first irq byte normally 0x08 */
  40 /* second irq byte base 0x7d + below */
  41 /* third irq byte base 0x94 + below */
  42 /* fourth irq byte normally 0xee */
  43
  44 /* second interrupt byte */
  45 #define CH341_MULT_STAT 0x04 /* multiple status since last interrupt event */
  46
  47 /* status returned in third interrupt answer byte, inverted in data
  48    from irq */
  49 #define CH341_BIT_CTS 0x01
  50 #define CH341_BIT_DSR 0x02
  51 #define CH341_BIT_RI  0x04
  52 #define CH341_BIT_DCD 0x08
  53 #define CH341_BITS_MODEM_STAT 0x0f /* all bits */
  54
  55 /*******************************/
  56 /* baudrate calculation factor */
  57 /*******************************/
  58 #define CH341_BAUDBASE_FACTOR 1532620800
  59 #define CH341_BAUDBASE_DIVMAX 3
  60
  61 /* Break support - the information used to implement this was gleaned from
  62  * the Net/FreeBSD uchcom.c driver by Takanori Watanabe.  Domo arigato.
  63  */
  64
  65 #define CH341_REQ_WRITE_REG    0x9A
  66 #define CH341_REQ_READ_REG     0x95
  67 #define CH341_REG_BREAK1       0x05
  68 #define CH341_REG_BREAK2       0x18
  69 #define CH341_NBREAK_BITS_REG1 0x01
  70 #define CH341_NBREAK_BITS_REG2 0x40
  71
  72
  73 static int debug;
  74
  75 static const struct usb_device_id id_table[] = {
  76         { USB_DEVICE(0x4348, 0x5523) },
  77         { USB_DEVICE(0x1a86, 0x7523) },
  78         { USB_DEVICE(0x1a86, 0x5523) },
  79         { },
  80 };
  81 MODULE_DEVICE_TABLE(usb, id_table);
  82
  83 struct ch341_private {
  84         spinlock_t lock; /* access lock */
  85         unsigned baud_rate; /* set baud rate */
  86         u8 line_control; /* set line control value RTS/DTR */
  87         u8 line_status; /* active status of modem control inputs */
  88         u8 multi_status_change; /* status changed multiple since last call */
  89 };
  90
  91 static void ch341_set_termios(struct tty_struct *tty,
  92                               struct usb_serial_port *port,
  93                               struct ktermios *old_termios);
  94
  95 static int ch341_control_out(struct usb_device *dev, u8 request,
  96                              u16 value, u16 index)
  97 {
  98         int r;
  99         dbg("ch341_control_out(%02x,%02x,%04x,%04x)", USB_DIR_OUT|0x40,
 100                 (int)request, (int)value, (int)index);
 101
 102         r = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), request,
 103                             USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT,
 104                             value, index, NULL, 0, DEFAULT_TIMEOUT);
 105
 106         return r;
 107 }
 108
 109 static int ch341_control_in(struct usb_device *dev,
 110                             u8 request, u16 value, u16 index,
 111                             char *buf, unsigned bufsize)
 112 {
 113         int r;
 114         dbg("ch341_control_in(%02x,%02x,%04x,%04x,%p,%u)", USB_DIR_IN|0x40,
 115                 (int)request, (int)value, (int)index, buf, (int)bufsize);
 116
 117         r = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), request,
 118                             USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
 119                             value, index, buf, bufsize, DEFAULT_TIMEOUT);
 120         return r;
 121 }
 122
 123 static int ch341_set_baudrate(struct usb_device *dev,
 124                               struct ch341_private *priv)
 125 {
 126         short a, b;
 127         int r;
 128         unsigned long factor;
 129         short divisor;
 130
 131         dbg("ch341_set_baudrate(%d)", priv->baud_rate);
 132
 133         if (!priv->baud_rate)
 134                 return -EINVAL;
 135         factor = (CH341_BAUDBASE_FACTOR / priv->baud_rate);
 136         divisor = CH341_BAUDBASE_DIVMAX;
 137
 138         while ((factor > 0xfff0) && divisor) {
 139                 factor >>= 3;
 140                 divisor--;
 141         }
 142
 143         if (factor > 0xfff0)
 144                 return -EINVAL;
 145
 146         factor = 0x10000 - factor;
 147         a = (factor & 0xff00) | divisor;
 148         b = factor & 0xff;
 149
 150         r = ch341_control_out(dev, 0x9a, 0x1312, a);
 151         if (!r)
 152                 r = ch341_control_out(dev, 0x9a, 0x0f2c, b);
 153
 154         return r;
 155 }
 156
 157 static int ch341_set_handshake(struct usb_device *dev, u8 control)
 158 {
 159         dbg("ch341_set_handshake(0x%02x)", control);
 160         return ch341_control_out(dev, 0xa4, ~control, 0);
 161 }
 162
 163 static int ch341_get_status(struct usb_device *dev, struct ch341_private *priv)
 164 {
 165         char *buffer;
 166         int r;
 167         const unsigned size = 8;
 168         unsigned long flags;
 169
 170         dbg("ch341_get_status()");
 171
 172         buffer = kmalloc(size, GFP_KERNEL);
 173         if (!buffer)
 174                 return -ENOMEM;
 175
 176         r = ch341_control_in(dev, 0x95, 0x0706, 0, buffer, size);
 177         if (r < 0)
 178                 goto out;
 179
 180         /* setup the private status if available */
 181         if (r == 2) {
 182                 r = 0;
 183                 spin_lock_irqsave(&priv->lock, flags);
 184                 priv->line_status = (~(*buffer)) & CH341_BITS_MODEM_STAT;
 185                 priv->multi_status_change = 0;
 186                 spin_unlock_irqrestore(&priv->lock, flags);
 187         } else
 188                 r = -EPROTO;
 189
 190 out:    kfree(buffer);
 191         return r;
 192 }
 193
 194 /* -------------------------------------------------------------------------- */
 195
 196 static int ch341_configure(struct usb_device *dev, struct ch341_private *priv)
 197 {
 198         char *buffer;
 199         int r;
 200         const unsigned size = 8;
 201
 202         dbg("ch341_configure()");
 203
 204         buffer = kmalloc(size, GFP_KERNEL);
 205         if (!buffer)
 206                 return -ENOMEM;
 207
 208         /* expect two bytes 0x27 0x00 */
 209         r = ch341_control_in(dev, 0x5f, 0, 0, buffer, size);
 210         if (r < 0)
 211                 goto out;
 212
 213         r = ch341_control_out(dev, 0xa1, 0, 0);
 214         if (r < 0)
 215                 goto out;
 216
 217         r = ch341_set_baudrate(dev, priv);
 218         if (r < 0)
 219                 goto out;
 220
 221         /* expect two bytes 0x56 0x00 */
 222         r = ch341_control_in(dev, 0x95, 0x2518, 0, buffer, size);
 223         if (r < 0)
 224                 goto out;
 225
 226         r = ch341_control_out(dev, 0x9a, 0x2518, 0x0050);
 227         if (r < 0)
 228                 goto out;
 229
 230         /* expect 0xff 0xee */
 231         r = ch341_get_status(dev, priv);
 232         if (r < 0)
 233                 goto out;
 234
 235         r = ch341_control_out(dev, 0xa1, 0x501f, 0xd90a);
 236         if (r < 0)
 237                 goto out;
 238
 239         r = ch341_set_baudrate(dev, priv);
 240         if (r < 0)
 241                 goto out;
 242
 243         r = ch341_set_handshake(dev, priv->line_control);
 244         if (r < 0)
 245                 goto out;
 246
 247         /* expect 0x9f 0xee */
 248         r = ch341_get_status(dev, priv);
 249
 250 out:    kfree(buffer);
 251         return r;
 252 }
 253
 254 /* allocate private data */
 255 static int ch341_attach(struct usb_serial *serial)
 256 {
 257         struct ch341_private *priv;
 258         int r;
 259
 260         dbg("ch341_attach()");
 261
 262         /* private data */
 263         priv = kzalloc(sizeof(struct ch341_private), GFP_KERNEL);
 264         if (!priv)
 265                 return -ENOMEM;
 266
 267         spin_lock_init(&priv->lock);
 268         priv->baud_rate = DEFAULT_BAUD_RATE;
 269         priv->line_control = CH341_BIT_RTS | CH341_BIT_DTR;
 270
 271         r = ch341_configure(serial->dev, priv);
 272         if (r < 0)
 273                 goto error;
 274
 275         usb_set_serial_port_data(serial->port[0], priv);
 276         return 0;
 277
 278 error:  kfree(priv);
 279         return r;
 280 }
 281
 282 static int ch341_carrier_raised(struct usb_serial_port *port)
 283 {
 284         struct ch341_private *priv = usb_get_serial_port_data(port);
 285         if (priv->line_status & CH341_BIT_DCD)
 286                 return 1;
 287         return 0;
 288 }
 289
 290 static void ch341_dtr_rts(struct usb_serial_port *port, int on)
 291 {
 292         struct ch341_private *priv = usb_get_serial_port_data(port);
 293         unsigned long flags;
 294
 295         dbg("%s - port %d", __func__, port->number);
 296         /* drop DTR and RTS */
 297         spin_lock_irqsave(&priv->lock, flags);
 298         if (on)
 299                 priv->line_control |= CH341_BIT_RTS | CH341_BIT_DTR;
 300         else
 301                 priv->line_control &= ~(CH341_BIT_RTS | CH341_BIT_DTR);
 302         spin_unlock_irqrestore(&priv->lock, flags);
 303         ch341_set_handshake(port->serial->dev, priv->line_control);
 304         wake_up_interruptible(&port->delta_msr_wait);
 305 }
 306
 307 static void ch341_close(struct usb_serial_port *port)
 308 {
 309         dbg("%s - port %d", __func__, port->number);
 310
 311         usb_serial_generic_close(port);
 312         usb_kill_urb(port->interrupt_in_urb);
 313 }
 314
 315
 316 /* open this device, set default parameters */
 317 static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port)
 318 {
 319         struct usb_serial *serial = port->serial;
 320         struct ch341_private *priv = usb_get_serial_port_data(serial->port[0]);
 321         int r;
 322
 323         dbg("ch341_open()");
 324
 325         r = ch341_configure(serial->dev, priv);
 326         if (r)
 327                 goto out;
 328
 329         if (tty)
 330                 ch341_set_termios(tty, port, NULL);
 331
 332         dbg("%s - submitting interrupt urb", __func__);
 333         port->interrupt_in_urb->dev = serial->dev;
 334         r = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
 335         if (r) {
 336                 dev_err(&port->dev, "%s - failed submitting interrupt urb,"
 337                         " error %d\n", __func__, r);
 338                 goto out;
 339         }
 340
 341         r = usb_serial_generic_open(tty, port);
 342
 343 out:    return r;
 344 }
 345
 346 /* Old_termios contains the original termios settings and
 347  * tty->termios contains the new setting to be used.
 348  */
 349 static void ch341_set_termios(struct tty_struct *tty,
 350                 struct usb_serial_port *port, struct ktermios *old_termios)
 351 {
 352         struct ch341_private *priv = usb_get_serial_port_data(port);
 353         unsigned baud_rate;
 354         unsigned long flags;
 355
 356         dbg("ch341_set_termios()");
 357
 358         baud_rate = tty_get_baud_rate(tty);
 359
 360         priv->baud_rate = baud_rate;
 361
 362         if (baud_rate) {
 363                 spin_lock_irqsave(&priv->lock, flags);
 364                 priv->line_control |= (CH341_BIT_DTR | CH341_BIT_RTS);
 365                 spin_unlock_irqrestore(&priv->lock, flags);
 366                 ch341_set_baudrate(port->serial->dev, priv);
 367         } else {
 368                 spin_lock_irqsave(&priv->lock, flags);
 369                 priv->line_control &= ~(CH341_BIT_DTR | CH341_BIT_RTS);
 370                 spin_unlock_irqrestore(&priv->lock, flags);
 371         }
 372
 373         ch341_set_handshake(port->serial->dev, priv->line_control);
 374
 375         /* Unimplemented:
 376          * (cflag & CSIZE) : data bits [5, 8]
 377          * (cflag & PARENB) : parity {NONE, EVEN, ODD}
 378          * (cflag & CSTOPB) : stop bits [1, 2]
 379          */
 380 }
 381
 382 static void ch341_break_ctl(struct tty_struct *tty, int break_state)
 383 {
 384         const uint16_t ch341_break_reg =
 385                 CH341_REG_BREAK1 | ((uint16_t) CH341_REG_BREAK2 << 8);
 386         struct usb_serial_port *port = tty->driver_data;
 387         int r;
 388         uint16_t reg_contents;
 389         uint8_t *break_reg;
 390
 391         dbg("%s()", __func__);
 392
 393         break_reg = kmalloc(2, GFP_KERNEL);
 394         if (!break_reg) {
 395                 dev_err(&port->dev, "%s - kmalloc failed\n", __func__);
 396                 return;
 397         }
 398
 399         r = ch341_control_in(port->serial->dev, CH341_REQ_READ_REG,
 400                         ch341_break_reg, 0, break_reg, 2);
 401         if (r < 0) {
 402                 dev_err(&port->dev, "%s - USB control read error (%d)\n",
 403                                 __func__, r);
 404                 goto out;
 405         }
 406         dbg("%s - initial ch341 break register contents - reg1: %x, reg2: %x",
 407                         __func__, break_reg[0], break_reg[1]);
 408         if (break_state != 0) {
 409                 dbg("%s - Enter break state requested", __func__);
 410                 break_reg[0] &= ~CH341_NBREAK_BITS_REG1;
 411                 break_reg[1] &= ~CH341_NBREAK_BITS_REG2;
 412         } else {
 413                 dbg("%s - Leave break state requested", __func__);
 414                 break_reg[0] |= CH341_NBREAK_BITS_REG1;
 415                 break_reg[1] |= CH341_NBREAK_BITS_REG2;
 416         }
 417         dbg("%s - New ch341 break register contents - reg1: %x, reg2: %x",
 418                         __func__, break_reg[0], break_reg[1]);
 419         reg_contents = get_unaligned_le16(break_reg);
 420         r = ch341_control_out(port->serial->dev, CH341_REQ_WRITE_REG,
 421                         ch341_break_reg, reg_contents);
 422         if (r < 0)
 423                 dev_err(&port->dev, "%s - USB control write error (%d)\n",
 424                                 __func__, r);
 425 out:
 426         kfree(break_reg);
 427 }
 428
 429 static int ch341_tiocmset(struct tty_struct *tty,
 430                           unsigned int set, unsigned int clear)
 431 {
 432         struct usb_serial_port *port = tty->driver_data;
 433         struct ch341_private *priv = usb_get_serial_port_data(port);
 434         unsigned long flags;
 435         u8 control;
 436
 437         spin_lock_irqsave(&priv->lock, flags);
 438         if (set & TIOCM_RTS)
 439                 priv->line_control |= CH341_BIT_RTS;
 440         if (set & TIOCM_DTR)
 441                 priv->line_control |= CH341_BIT_DTR;
 442         if (clear & TIOCM_RTS)
 443                 priv->line_control &= ~CH341_BIT_RTS;
 444         if (clear & TIOCM_DTR)
 445                 priv->line_control &= ~CH341_BIT_DTR;
 446         control = priv->line_control;
 447         spin_unlock_irqrestore(&priv->lock, flags);
 448
 449         return ch341_set_handshake(port->serial->dev, control);
 450 }
 451
 452 static void ch341_read_int_callback(struct urb *urb)
 453 {
 454         struct usb_serial_port *port = (struct usb_serial_port *) urb->context;
 455         unsigned char *data = urb->transfer_buffer;
 456         unsigned int actual_length = urb->actual_length;
 457         int status;
 458
 459         dbg("%s (%d)", __func__, port->number);
 460
 461         switch (urb->status) {
 462         case 0:
 463                 /* success */
 464                 break;
 465         case -ECONNRESET:
 466         case -ENOENT:
 467         case -ESHUTDOWN:
 468                 /* this urb is terminated, clean up */
 469                 dbg("%s - urb shutting down with status: %d", __func__,
 470                     urb->status);
 471                 return;
 472         default:
 473                 dbg("%s - nonzero urb status received: %d", __func__,
 474                     urb->status);
 475                 goto exit;
 476         }
 477
 478         usb_serial_debug_data(debug, &port->dev, __func__,
 479                               urb->actual_length, urb->transfer_buffer);
 480
 481         if (actual_length >= 4) {
 482                 struct ch341_private *priv = usb_get_serial_port_data(port);
 483                 unsigned long flags;
 484                 u8 prev_line_status = priv->line_status;
 485
 486                 spin_lock_irqsave(&priv->lock, flags);
 487                 priv->line_status = (~(data[2])) & CH341_BITS_MODEM_STAT;
 488                 if ((data[1] & CH341_MULT_STAT))
 489                         priv->multi_status_change = 1;
 490                 spin_unlock_irqrestore(&priv->lock, flags);
 491
 492                 if ((priv->line_status ^ prev_line_status) & CH341_BIT_DCD) {
 493                         struct tty_struct *tty = tty_port_tty_get(&port->port);
 494                         if (tty)
 495                                 usb_serial_handle_dcd_change(port, tty,
 496                                             priv->line_status & CH341_BIT_DCD);
 497                         tty_kref_put(tty);
 498                 }
 499
 500                 wake_up_interruptible(&port->delta_msr_wait);
 501         }
 502
 503 exit:
 504         status = usb_submit_urb(urb, GFP_ATOMIC);
 505         if (status)
 506                 dev_err(&urb->dev->dev,
 507                         "%s - usb_submit_urb failed with result %d\n",
 508                         __func__, status);
 509 }
 510
 511 static int wait_modem_info(struct usb_serial_port *port, unsigned int arg)
 512 {
 513         struct ch341_private *priv = usb_get_serial_port_data(port);
 514         unsigned long flags;
 515         u8 prevstatus;
 516         u8 status;
 517         u8 changed;
 518         u8 multi_change = 0;
 519
 520         spin_lock_irqsave(&priv->lock, flags);
 521         prevstatus = priv->line_status;
 522         priv->multi_status_change = 0;
 523         spin_unlock_irqrestore(&priv->lock, flags);
 524
 525         while (!multi_change) {
 526                 interruptible_sleep_on(&port->delta_msr_wait);
 527                 /* see if a signal did it */
 528                 if (signal_pending(current))
 529                         return -ERESTARTSYS;
 530
 531                 if (port->serial->disconnected)
 532                         return -EIO;
 533
 534                 spin_lock_irqsave(&priv->lock, flags);
 535                 status = priv->line_status;
 536                 multi_change = priv->multi_status_change;
 537                 spin_unlock_irqrestore(&priv->lock, flags);
 538
 539                 changed = prevstatus ^ status;
 540
 541                 if (((arg & TIOCM_RNG) && (changed & CH341_BIT_RI)) ||
 542                     ((arg & TIOCM_DSR) && (changed & CH341_BIT_DSR)) ||
 543                     ((arg & TIOCM_CD)  && (changed & CH341_BIT_DCD)) ||
 544                     ((arg & TIOCM_CTS) && (changed & CH341_BIT_CTS))) {
 545                         return 0;
 546                 }
 547                 prevstatus = status;
 548         }
 549
 550         return 0;
 551 }
 552
 553 static int ch341_ioctl(struct tty_struct *tty,
 554                         unsigned int cmd, unsigned long arg)
 555 {
 556         struct usb_serial_port *port = tty->driver_data;
 557         dbg("%s (%d) cmd = 0x%04x", __func__, port->number, cmd);
 558
 559         switch (cmd) {
 560         case TIOCMIWAIT:
 561                 dbg("%s (%d) TIOCMIWAIT", __func__,  port->number);
 562                 return wait_modem_info(port, arg);
 563
 564         default:
 565                 dbg("%s not supported = 0x%04x", __func__, cmd);
 566                 break;
 567         }
 568
 569         return -ENOIOCTLCMD;
 570 }
 571
 572 static int ch341_tiocmget(struct tty_struct *tty)
 573 {
 574         struct usb_serial_port *port = tty->driver_data;
 575         struct ch341_private *priv = usb_get_serial_port_data(port);
 576         unsigned long flags;
 577         u8 mcr;
 578         u8 status;
 579         unsigned int result;
 580
 581         dbg("%s (%d)", __func__, port->number);
 582
 583         spin_lock_irqsave(&priv->lock, flags);
 584         mcr = priv->line_control;
 585         status = priv->line_status;
 586         spin_unlock_irqrestore(&priv->lock, flags);
 587
 588         result = ((mcr & CH341_BIT_DTR)         ? TIOCM_DTR : 0)
 589                   | ((mcr & CH341_BIT_RTS)      ? TIOCM_RTS : 0)
 590                   | ((status & CH341_BIT_CTS)   ? TIOCM_CTS : 0)
 591                   | ((status & CH341_BIT_DSR)   ? TIOCM_DSR : 0)
 592                   | ((status & CH341_BIT_RI)    ? TIOCM_RI  : 0)
 593                   | ((status & CH341_BIT_DCD)   ? TIOCM_CD  : 0);
 594
 595         dbg("%s - result = %x", __func__, result);
 596
 597         return result;
 598 }
 599
 600
 601 static int ch341_reset_resume(struct usb_interface *intf)
 602 {
 603         struct usb_device *dev = interface_to_usbdev(intf);
 604         struct usb_serial *serial = NULL;
 605         struct ch341_private *priv;
 606
 607         serial = usb_get_intfdata(intf);
 608         priv = usb_get_serial_port_data(serial->port[0]);
 609
 610         /*reconfigure ch341 serial port after bus-reset*/
 611         ch341_configure(dev, priv);
 612
 613         usb_serial_resume(intf);
 614
 615         return 0;
 616 }
 617
 618 static struct usb_driver ch341_driver = {
 619         .name           = "ch341",
 620         .probe          = usb_serial_probe,
 621         .disconnect     = usb_serial_disconnect,
 622         .suspend        = usb_serial_suspend,
 623         .resume         = usb_serial_resume,
 624         .reset_resume   = ch341_reset_resume,
 625         .id_table       = id_table,
 626         .no_dynamic_id  = 1,
 627         .supports_autosuspend = 1,
 628 };
 629
 630 static struct usb_serial_driver ch341_device = {
 631         .driver = {
 632                 .owner  = THIS_MODULE,
 633                 .name   = "ch341-uart",
 634         },
 635         .id_table          = id_table,
 636         .usb_driver        = &ch341_driver,
 637         .num_ports         = 1,
 638         .open              = ch341_open,
 639         .dtr_rts           = ch341_dtr_rts,
 640         .carrier_raised    = ch341_carrier_raised,
 641         .close             = ch341_close,
 642         .ioctl             = ch341_ioctl,
 643         .set_termios       = ch341_set_termios,
 644         .break_ctl         = ch341_break_ctl,
 645         .tiocmget          = ch341_tiocmget,
 646         .tiocmset          = ch341_tiocmset,
 647         .read_int_callback = ch341_read_int_callback,
 648         .attach            = ch341_attach,
 649 };
 650
 651 static int __init ch341_init(void)
 652 {
 653         int retval;
 654
 655         retval = usb_serial_register(&ch341_device);
 656         if (retval)
 657                 return retval;
 658         retval = usb_register(&ch341_driver);
 659         if (retval)
 660                 usb_serial_deregister(&ch341_device);
 661         return retval;
 662 }
 663
 664 static void __exit ch341_exit(void)
 665 {
 666         usb_deregister(&ch341_driver);
 667         usb_serial_deregister(&ch341_device);
 668 }
 669
 670 module_init(ch341_init);
 671 module_exit(ch341_exit);
 672 MODULE_LICENSE("GPL");
 673
 674 module_param(debug, bool, S_IRUGO | S_IWUSR);
 675 MODULE_PARM_DESC(debug, "Debug enabled or not");
 676
 677 /* EOF ch341.c */