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 int ch341_control_out(struct usb_device *dev, u8 request,
  92                              u16 value, u16 index)
  93 {
  94         int r;
  95         dbg("ch341_control_out(%02x,%02x,%04x,%04x)", USB_DIR_OUT|0x40,
  96                 (int)request, (int)value, (int)index);
  97
  98         r = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), request,
  99                             USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT,
 100                             value, index, NULL, 0, DEFAULT_TIMEOUT);
 101
 102         return r;
 103 }
 104
 105 static int ch341_control_in(struct usb_device *dev,
 106                             u8 request, u16 value, u16 index,
 107                             char *buf, unsigned bufsize)
 108 {
 109         int r;
 110         dbg("ch341_control_in(%02x,%02x,%04x,%04x,%p,%u)", USB_DIR_IN|0x40,
 111                 (int)request, (int)value, (int)index, buf, (int)bufsize);
 112
 113         r = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), request,
 114                             USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
 115                             value, index, buf, bufsize, DEFAULT_TIMEOUT);
 116         return r;
 117 }
 118
 119 static int ch341_set_baudrate(struct usb_device *dev,
 120                               struct ch341_private *priv)
 121 {
 122         short a, b;
 123         int r;
 124         unsigned long factor;
 125         short divisor;
 126
 127         dbg("ch341_set_baudrate(%d)", priv->baud_rate);
 128
 129         if (!priv->baud_rate)
 130                 return -EINVAL;
 131         factor = (CH341_BAUDBASE_FACTOR / priv->baud_rate);
 132         divisor = CH341_BAUDBASE_DIVMAX;
 133
 134         while ((factor > 0xfff0) && divisor) {
 135                 factor >>= 3;
 136                 divisor--;
 137         }
 138
 139         if (factor > 0xfff0)
 140                 return -EINVAL;
 141
 142         factor = 0x10000 - factor;
 143         a = (factor & 0xff00) | divisor;
 144         b = factor & 0xff;
 145
 146         r = ch341_control_out(dev, 0x9a, 0x1312, a);
 147         if (!r)
 148                 r = ch341_control_out(dev, 0x9a, 0x0f2c, b);
 149
 150         return r;
 151 }
 152
 153 static int ch341_set_handshake(struct usb_device *dev, u8 control)
 154 {
 155         dbg("ch341_set_handshake(0x%02x)", control);
 156         return ch341_control_out(dev, 0xa4, ~control, 0);
 157 }
 158
 159 static int ch341_get_status(struct usb_device *dev, struct ch341_private *priv)
 160 {
 161         char *buffer;
 162         int r;
 163         const unsigned size = 8;
 164         unsigned long flags;
 165
 166         dbg("ch341_get_status()");
 167
 168         buffer = kmalloc(size, GFP_KERNEL);
 169         if (!buffer)
 170                 return -ENOMEM;
 171
 172         r = ch341_control_in(dev, 0x95, 0x0706, 0, buffer, size);
 173         if (r < 0)
 174                 goto out;
 175
 176         /* setup the private status if available */
 177         if (r == 2) {
 178                 r = 0;
 179                 spin_lock_irqsave(&priv->lock, flags);
 180                 priv->line_status = (~(*buffer)) & CH341_BITS_MODEM_STAT;
 181                 priv->multi_status_change = 0;
 182                 spin_unlock_irqrestore(&priv->lock, flags);
 183         } else
 184                 r = -EPROTO;
 185
 186 out:    kfree(buffer);
 187         return r;
 188 }
 189
 190 /* -------------------------------------------------------------------------- */
 191
 192 static int ch341_configure(struct usb_device *dev, struct ch341_private *priv)
 193 {
 194         char *buffer;
 195         int r;
 196         const unsigned size = 8;
 197
 198         dbg("ch341_configure()");
 199
 200         buffer = kmalloc(size, GFP_KERNEL);
 201         if (!buffer)
 202                 return -ENOMEM;
 203
 204         /* expect two bytes 0x27 0x00 */
 205         r = ch341_control_in(dev, 0x5f, 0, 0, buffer, size);
 206         if (r < 0)
 207                 goto out;
 208
 209         r = ch341_control_out(dev, 0xa1, 0, 0);
 210         if (r < 0)
 211                 goto out;
 212
 213         r = ch341_set_baudrate(dev, priv);
 214         if (r < 0)
 215                 goto out;
 216
 217         /* expect two bytes 0x56 0x00 */
 218         r = ch341_control_in(dev, 0x95, 0x2518, 0, buffer, size);
 219         if (r < 0)
 220                 goto out;
 221
 222         r = ch341_control_out(dev, 0x9a, 0x2518, 0x0050);
 223         if (r < 0)
 224                 goto out;
 225
 226         /* expect 0xff 0xee */
 227         r = ch341_get_status(dev, priv);
 228         if (r < 0)
 229                 goto out;
 230
 231         r = ch341_control_out(dev, 0xa1, 0x501f, 0xd90a);
 232         if (r < 0)
 233                 goto out;
 234
 235         r = ch341_set_baudrate(dev, priv);
 236         if (r < 0)
 237                 goto out;
 238
 239         r = ch341_set_handshake(dev, priv->line_control);
 240         if (r < 0)
 241                 goto out;
 242
 243         /* expect 0x9f 0xee */
 244         r = ch341_get_status(dev, priv);
 245
 246 out:    kfree(buffer);
 247         return r;
 248 }
 249
 250 /* allocate private data */
 251 static int ch341_attach(struct usb_serial *serial)
 252 {
 253         struct ch341_private *priv;
 254         int r;
 255
 256         dbg("ch341_attach()");
 257
 258         /* private data */
 259         priv = kzalloc(sizeof(struct ch341_private), GFP_KERNEL);
 260         if (!priv)
 261                 return -ENOMEM;
 262
 263         spin_lock_init(&priv->lock);
 264         priv->baud_rate = DEFAULT_BAUD_RATE;
 265         priv->line_control = CH341_BIT_RTS | CH341_BIT_DTR;
 266
 267         r = ch341_configure(serial->dev, priv);
 268         if (r < 0)
 269                 goto error;
 270
 271         usb_set_serial_port_data(serial->port[0], priv);
 272         return 0;
 273
 274 error:  kfree(priv);
 275         return r;
 276 }
 277
 278 static int ch341_carrier_raised(struct usb_serial_port *port)
 279 {
 280         struct ch341_private *priv = usb_get_serial_port_data(port);
 281         if (priv->line_status & CH341_BIT_DCD)
 282                 return 1;
 283         return 0;
 284 }
 285
 286 static void ch341_dtr_rts(struct usb_serial_port *port, int on)
 287 {
 288         struct ch341_private *priv = usb_get_serial_port_data(port);
 289         unsigned long flags;
 290
 291         dbg("%s - port %d", __func__, port->number);
 292         /* drop DTR and RTS */
 293         spin_lock_irqsave(&priv->lock, flags);
 294         if (on)
 295                 priv->line_control |= CH341_BIT_RTS | CH341_BIT_DTR;
 296         else
 297                 priv->line_control &= ~(CH341_BIT_RTS | CH341_BIT_DTR);
 298         spin_unlock_irqrestore(&priv->lock, flags);
 299         ch341_set_handshake(port->serial->dev, priv->line_control);
 300         wake_up_interruptible(&port->delta_msr_wait);
 301 }
 302
 303 static void ch341_close(struct usb_serial_port *port)
 304 {
 305         dbg("%s - port %d", __func__, port->number);
 306
 307         usb_serial_generic_close(port);
 308         usb_kill_urb(port->interrupt_in_urb);
 309 }
 310
 311
 312 /* open this device, set default parameters */
 313 static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port)
 314 {
 315         struct usb_serial *serial = port->serial;
 316         struct ch341_private *priv = usb_get_serial_port_data(serial->port[0]);
 317         int r;
 318
 319         dbg("ch341_open()");
 320
 321         priv->baud_rate = DEFAULT_BAUD_RATE;
 322
 323         r = ch341_configure(serial->dev, priv);
 324         if (r)
 325                 goto out;
 326
 327         r = ch341_set_handshake(serial->dev, priv->line_control);
 328         if (r)
 329                 goto out;
 330
 331         r = ch341_set_baudrate(serial->dev, priv);
 332         if (r)
 333                 goto out;
 334
 335         dbg("%s - submitting interrupt urb", __func__);
 336         port->interrupt_in_urb->dev = serial->dev;
 337         r = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
 338         if (r) {
 339                 dev_err(&port->dev, "%s - failed submitting interrupt urb,"
 340                         " error %d\n", __func__, r);
 341                 goto out;
 342         }
 343
 344         r = usb_serial_generic_open(tty, port);
 345
 346 out:    return r;
 347 }
 348
 349 /* Old_termios contains the original termios settings and
 350  * tty->termios contains the new setting to be used.
 351  */
 352 static void ch341_set_termios(struct tty_struct *tty,
 353                 struct usb_serial_port *port, struct ktermios *old_termios)
 354 {
 355         struct ch341_private *priv = usb_get_serial_port_data(port);
 356         unsigned baud_rate;
 357         unsigned long flags;
 358
 359         dbg("ch341_set_termios()");
 360
 361         baud_rate = tty_get_baud_rate(tty);
 362
 363         priv->baud_rate = baud_rate;
 364
 365         if (baud_rate) {
 366                 spin_lock_irqsave(&priv->lock, flags);
 367                 priv->line_control |= (CH341_BIT_DTR | CH341_BIT_RTS);
 368                 spin_unlock_irqrestore(&priv->lock, flags);
 369                 ch341_set_baudrate(port->serial->dev, priv);
 370         } else {
 371                 spin_lock_irqsave(&priv->lock, flags);
 372                 priv->line_control &= ~(CH341_BIT_DTR | CH341_BIT_RTS);
 373                 spin_unlock_irqrestore(&priv->lock, flags);
 374         }
 375
 376         ch341_set_handshake(port->serial->dev, priv->line_control);
 377
 378         /* Unimplemented:
 379          * (cflag & CSIZE) : data bits [5, 8]
 380          * (cflag & PARENB) : parity {NONE, EVEN, ODD}
 381          * (cflag & CSTOPB) : stop bits [1, 2]
 382          */
 383 }
 384
 385 static void ch341_break_ctl(struct tty_struct *tty, int break_state)
 386 {
 387         const uint16_t ch341_break_reg =
 388                 CH341_REG_BREAK1 | ((uint16_t) CH341_REG_BREAK2 << 8);
 389         struct usb_serial_port *port = tty->driver_data;
 390         int r;
 391         uint16_t reg_contents;
 392         uint8_t *break_reg;
 393
 394         dbg("%s()", __func__);
 395
 396         break_reg = kmalloc(2, GFP_KERNEL);
 397         if (!break_reg) {
 398                 dev_err(&port->dev, "%s - kmalloc failed\n", __func__);
 399                 return;
 400         }
 401
 402         r = ch341_control_in(port->serial->dev, CH341_REQ_READ_REG,
 403                         ch341_break_reg, 0, break_reg, 2);
 404         if (r < 0) {
 405                 dev_err(&port->dev, "%s - USB control read error (%d)\n",
 406                                 __func__, r);
 407                 goto out;
 408         }
 409         dbg("%s - initial ch341 break register contents - reg1: %x, reg2: %x",
 410                         __func__, break_reg[0], break_reg[1]);
 411         if (break_state != 0) {
 412                 dbg("%s - Enter break state requested", __func__);
 413                 break_reg[0] &= ~CH341_NBREAK_BITS_REG1;
 414                 break_reg[1] &= ~CH341_NBREAK_BITS_REG2;
 415         } else {
 416                 dbg("%s - Leave break state requested", __func__);
 417                 break_reg[0] |= CH341_NBREAK_BITS_REG1;
 418                 break_reg[1] |= CH341_NBREAK_BITS_REG2;
 419         }
 420         dbg("%s - New ch341 break register contents - reg1: %x, reg2: %x",
 421                         __func__, break_reg[0], break_reg[1]);
 422         reg_contents = get_unaligned_le16(break_reg);
 423         r = ch341_control_out(port->serial->dev, CH341_REQ_WRITE_REG,
 424                         ch341_break_reg, reg_contents);
 425         if (r < 0)
 426                 dev_err(&port->dev, "%s - USB control write error (%d)\n",
 427                                 __func__, r);
 428 out:
 429         kfree(break_reg);
 430 }
 431
 432 static int ch341_tiocmset(struct tty_struct *tty,
 433                           unsigned int set, unsigned int clear)
 434 {
 435         struct usb_serial_port *port = tty->driver_data;
 436         struct ch341_private *priv = usb_get_serial_port_data(port);
 437         unsigned long flags;
 438         u8 control;
 439
 440         spin_lock_irqsave(&priv->lock, flags);
 441         if (set & TIOCM_RTS)
 442                 priv->line_control |= CH341_BIT_RTS;
 443         if (set & TIOCM_DTR)
 444                 priv->line_control |= CH341_BIT_DTR;
 445         if (clear & TIOCM_RTS)
 446                 priv->line_control &= ~CH341_BIT_RTS;
 447         if (clear & TIOCM_DTR)
 448                 priv->line_control &= ~CH341_BIT_DTR;
 449         control = priv->line_control;
 450         spin_unlock_irqrestore(&priv->lock, flags);
 451
 452         return ch341_set_handshake(port->serial->dev, control);
 453 }
 454
 455 static void ch341_read_int_callback(struct urb *urb)
 456 {
 457         struct usb_serial_port *port = (struct usb_serial_port *) urb->context;
 458         unsigned char *data = urb->transfer_buffer;
 459         unsigned int actual_length = urb->actual_length;
 460         int status;
 461
 462         dbg("%s (%d)", __func__, port->number);
 463
 464         switch (urb->status) {
 465         case 0:
 466                 /* success */
 467                 break;
 468         case -ECONNRESET:
 469         case -ENOENT:
 470         case -ESHUTDOWN:
 471                 /* this urb is terminated, clean up */
 472                 dbg("%s - urb shutting down with status: %d", __func__,
 473                     urb->status);
 474                 return;
 475         default:
 476                 dbg("%s - nonzero urb status received: %d", __func__,
 477                     urb->status);
 478                 goto exit;
 479         }
 480
 481         usb_serial_debug_data(debug, &port->dev, __func__,
 482                               urb->actual_length, urb->transfer_buffer);
 483
 484         if (actual_length >= 4) {
 485                 struct ch341_private *priv = usb_get_serial_port_data(port);
 486                 unsigned long flags;
 487                 u8 prev_line_status = priv->line_status;
 488
 489                 spin_lock_irqsave(&priv->lock, flags);
 490                 priv->line_status = (~(data[2])) & CH341_BITS_MODEM_STAT;
 491                 if ((data[1] & CH341_MULT_STAT))
 492                         priv->multi_status_change = 1;
 493                 spin_unlock_irqrestore(&priv->lock, flags);
 494
 495                 if ((priv->line_status ^ prev_line_status) & CH341_BIT_DCD) {
 496                         struct tty_struct *tty = tty_port_tty_get(&port->port);
 497                         if (tty)
 498                                 usb_serial_handle_dcd_change(port, tty,
 499                                             priv->line_status & CH341_BIT_DCD);
 500                         tty_kref_put(tty);
 501                 }
 502
 503                 wake_up_interruptible(&port->delta_msr_wait);
 504         }
 505
 506 exit:
 507         status = usb_submit_urb(urb, GFP_ATOMIC);
 508         if (status)
 509                 dev_err(&urb->dev->dev,
 510                         "%s - usb_submit_urb failed with result %d\n",
 511                         __func__, status);
 512 }
 513
 514 static int wait_modem_info(struct usb_serial_port *port, unsigned int arg)
 515 {
 516         struct ch341_private *priv = usb_get_serial_port_data(port);
 517         unsigned long flags;
 518         u8 prevstatus;
 519         u8 status;
 520         u8 changed;
 521         u8 multi_change = 0;
 522
 523         spin_lock_irqsave(&priv->lock, flags);
 524         prevstatus = priv->line_status;
 525         priv->multi_status_change = 0;
 526         spin_unlock_irqrestore(&priv->lock, flags);
 527
 528         while (!multi_change) {
 529                 interruptible_sleep_on(&port->delta_msr_wait);
 530                 /* see if a signal did it */
 531                 if (signal_pending(current))
 532                         return -ERESTARTSYS;
 533
 534                 if (port->serial->disconnected)
 535                         return -EIO;
 536
 537                 spin_lock_irqsave(&priv->lock, flags);
 538                 status = priv->line_status;
 539                 multi_change = priv->multi_status_change;
 540                 spin_unlock_irqrestore(&priv->lock, flags);
 541
 542                 changed = prevstatus ^ status;
 543
 544                 if (((arg & TIOCM_RNG) && (changed & CH341_BIT_RI)) ||
 545                     ((arg & TIOCM_DSR) && (changed & CH341_BIT_DSR)) ||
 546                     ((arg & TIOCM_CD)  && (changed & CH341_BIT_DCD)) ||
 547                     ((arg & TIOCM_CTS) && (changed & CH341_BIT_CTS))) {
 548                         return 0;
 549                 }
 550                 prevstatus = status;
 551         }
 552
 553         return 0;
 554 }
 555
 556 static int ch341_ioctl(struct tty_struct *tty,
 557                         unsigned int cmd, unsigned long arg)
 558 {
 559         struct usb_serial_port *port = tty->driver_data;
 560         dbg("%s (%d) cmd = 0x%04x", __func__, port->number, cmd);
 561
 562         switch (cmd) {
 563         case TIOCMIWAIT:
 564                 dbg("%s (%d) TIOCMIWAIT", __func__,  port->number);
 565                 return wait_modem_info(port, arg);
 566
 567         default:
 568                 dbg("%s not supported = 0x%04x", __func__, cmd);
 569                 break;
 570         }
 571
 572         return -ENOIOCTLCMD;
 573 }
 574
 575 static int ch341_tiocmget(struct tty_struct *tty)
 576 {
 577         struct usb_serial_port *port = tty->driver_data;
 578         struct ch341_private *priv = usb_get_serial_port_data(port);
 579         unsigned long flags;
 580         u8 mcr;
 581         u8 status;
 582         unsigned int result;
 583
 584         dbg("%s (%d)", __func__, port->number);
 585
 586         spin_lock_irqsave(&priv->lock, flags);
 587         mcr = priv->line_control;
 588         status = priv->line_status;
 589         spin_unlock_irqrestore(&priv->lock, flags);
 590
 591         result = ((mcr & CH341_BIT_DTR)         ? TIOCM_DTR : 0)
 592                   | ((mcr & CH341_BIT_RTS)      ? TIOCM_RTS : 0)
 593                   | ((status & CH341_BIT_CTS)   ? TIOCM_CTS : 0)
 594                   | ((status & CH341_BIT_DSR)   ? TIOCM_DSR : 0)
 595                   | ((status & CH341_BIT_RI)    ? TIOCM_RI  : 0)
 596                   | ((status & CH341_BIT_DCD)   ? TIOCM_CD  : 0);
 597
 598         dbg("%s - result = %x", __func__, result);
 599
 600         return result;
 601 }
 602
 603
 604 static int ch341_reset_resume(struct usb_interface *intf)
 605 {
 606         struct usb_device *dev = interface_to_usbdev(intf);
 607         struct usb_serial *serial = NULL;
 608         struct ch341_private *priv;
 609
 610         serial = usb_get_intfdata(intf);
 611         priv = usb_get_serial_port_data(serial->port[0]);
 612
 613         /*reconfigure ch341 serial port after bus-reset*/
 614         ch341_configure(dev, priv);
 615
 616         usb_serial_resume(intf);
 617
 618         return 0;
 619 }
 620
 621 static struct usb_driver ch341_driver = {
 622         .name           = "ch341",
 623         .probe          = usb_serial_probe,
 624         .disconnect     = usb_serial_disconnect,
 625         .suspend        = usb_serial_suspend,
 626         .resume         = usb_serial_resume,
 627         .reset_resume   = ch341_reset_resume,
 628         .id_table       = id_table,
 629         .no_dynamic_id  = 1,
 630         .supports_autosuspend = 1,
 631 };
 632
 633 static struct usb_serial_driver ch341_device = {
 634         .driver = {
 635                 .owner  = THIS_MODULE,
 636                 .name   = "ch341-uart",
 637         },
 638         .id_table          = id_table,
 639         .usb_driver        = &ch341_driver,
 640         .num_ports         = 1,
 641         .open              = ch341_open,
 642         .dtr_rts           = ch341_dtr_rts,
 643         .carrier_raised    = ch341_carrier_raised,
 644         .close             = ch341_close,
 645         .ioctl             = ch341_ioctl,
 646         .set_termios       = ch341_set_termios,
 647         .break_ctl         = ch341_break_ctl,
 648         .tiocmget          = ch341_tiocmget,
 649         .tiocmset          = ch341_tiocmset,
 650         .read_int_callback = ch341_read_int_callback,
 651         .attach            = ch341_attach,
 652 };
 653
 654 static int __init ch341_init(void)
 655 {
 656         int retval;
 657
 658         retval = usb_serial_register(&ch341_device);
 659         if (retval)
 660                 return retval;
 661         retval = usb_register(&ch341_driver);
 662         if (retval)
 663                 usb_serial_deregister(&ch341_device);
 664         return retval;
 665 }
 666
 667 static void __exit ch341_exit(void)
 668 {
 669         usb_deregister(&ch341_driver);
 670         usb_serial_deregister(&ch341_device);
 671 }
 672
 673 module_init(ch341_init);
 674 module_exit(ch341_exit);
 675 MODULE_LICENSE("GPL");
 676
 677 module_param(debug, bool, S_IRUGO | S_IWUSR);
 678 MODULE_PARM_DESC(debug, "Debug enabled or not");
 679
 680 /* EOF ch341.c */