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_READ_VERSION 0x5F
  66 #define CH341_REQ_WRITE_REG    0x9A
  67 #define CH341_REQ_READ_REG     0x95
  68 #define CH341_REQ_SERIAL_INIT  0xA1
  69 #define CH341_REQ_MODEM_CTRL   0xA4
  70
  71 #define CH341_REG_BREAK        0x05
  72 #define CH341_REG_LCR          0x18
  73 #define CH341_NBREAK_BITS      0x01
  74
  75 #define CH341_LCR_ENABLE_RX    0x80
  76 #define CH341_LCR_ENABLE_TX    0x40
  77 #define CH341_LCR_MARK_SPACE   0x20
  78 #define CH341_LCR_PAR_EVEN     0x10
  79 #define CH341_LCR_ENABLE_PAR   0x08
  80 #define CH341_LCR_STOP_BITS_2  0x04
  81 #define CH341_LCR_CS8          0x03
  82 #define CH341_LCR_CS7          0x02
  83 #define CH341_LCR_CS6          0x01
  84 #define CH341_LCR_CS5          0x00
  85
  86 static int debug;
  87
  88 static const struct usb_device_id id_table[] = {
  89         { USB_DEVICE(0x4348, 0x5523) },
  90         { USB_DEVICE(0x1a86, 0x7523) },
  91         { USB_DEVICE(0x1a86, 0x5523) },
  92         { },
  93 };
  94 MODULE_DEVICE_TABLE(usb, id_table);
  95
  96 struct ch341_private {
  97         spinlock_t lock; /* access lock */
  98         unsigned baud_rate; /* set baud rate */
  99         u8 line_control; /* set line control value RTS/DTR */
 100         u8 line_status; /* active status of modem control inputs */
 101         u8 multi_status_change; /* status changed multiple since last call */
 102 };
 103
 104 static void ch341_set_termios(struct tty_struct *tty,
 105                               struct usb_serial_port *port,
 106                               struct ktermios *old_termios);
 107
 108 static int ch341_control_out(struct usb_device *dev, u8 request,
 109                              u16 value, u16 index)
 110 {
 111         int r;
 112         dbg("ch341_control_out(%02x,%02x,%04x,%04x)", USB_DIR_OUT|0x40,
 113                 (int)request, (int)value, (int)index);
 114
 115         r = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), request,
 116                             USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT,
 117                             value, index, NULL, 0, DEFAULT_TIMEOUT);
 118         if (r < 0)
 119                 dev_err(&dev->dev, "failed to send control message: %d\n", r);
 120
 121         return r;
 122 }
 123
 124 static int ch341_control_in(struct usb_device *dev,
 125                             u8 request, u16 value, u16 index,
 126                             char *buf, unsigned bufsize)
 127 {
 128         int r;
 129         dbg("ch341_control_in(%02x,%02x,%04x,%04x,%p,%u)", USB_DIR_IN|0x40,
 130                 (int)request, (int)value, (int)index, buf, (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         dbg("ch341_set_baudrate(%d)", priv->baud_rate);
 160
 161         if (!priv->baud_rate)
 162                 return -EINVAL;
 163         factor = (CH341_BAUDBASE_FACTOR / priv->baud_rate);
 164         divisor = CH341_BAUDBASE_DIVMAX;
 165
 166         while ((factor > 0xfff0) && divisor) {
 167                 factor >>= 3;
 168                 divisor--;
 169         }
 170
 171         if (factor > 0xfff0)
 172                 return -EINVAL;
 173
 174         factor = 0x10000 - factor;
 175         a = (factor & 0xff00) | divisor;
 176
 177         /*
 178          * CH341A buffers data until a full endpoint-size packet (32 bytes)
 179          * has been received unless bit 7 is set.
 180          */
 181         a |= BIT(7);
 182
 183         r = ch341_control_out(dev, CH341_REQ_WRITE_REG, 0x1312, a);
 184         if (r)
 185                 return r;
 186
 187         r = ch341_control_out(dev, CH341_REQ_WRITE_REG, 0x2518, lcr);
 188         if (r)
 189                 return r;
 190
 191         return r;
 192 }
 193
 194 static int ch341_set_handshake(struct usb_device *dev, u8 control)
 195 {
 196         dbg("ch341_set_handshake(0x%02x)", control);
 197         return ch341_control_out(dev, CH341_REQ_MODEM_CTRL, ~control, 0);
 198 }
 199
 200 static int ch341_get_status(struct usb_device *dev, struct ch341_private *priv)
 201 {
 202         const unsigned int size = 2;
 203         char *buffer;
 204         int r;
 205         unsigned long flags;
 206
 207         dbg("ch341_get_status()");
 208
 209         buffer = kmalloc(size, GFP_KERNEL);
 210         if (!buffer)
 211                 return -ENOMEM;
 212
 213         r = ch341_control_in(dev, CH341_REQ_READ_REG, 0x0706, 0, buffer, size);
 214         if (r < 0)
 215                 goto out;
 216
 217         spin_lock_irqsave(&priv->lock, flags);
 218         priv->line_status = (~(*buffer)) & CH341_BITS_MODEM_STAT;
 219         priv->multi_status_change = 0;
 220         spin_unlock_irqrestore(&priv->lock, flags);
 221
 222 out:    kfree(buffer);
 223         return r;
 224 }
 225
 226 /* -------------------------------------------------------------------------- */
 227
 228 static int ch341_configure(struct usb_device *dev, struct ch341_private *priv)
 229 {
 230         const unsigned int size = 2;
 231         char *buffer;
 232         int r;
 233
 234         dbg("ch341_configure()");
 235
 236         buffer = kmalloc(size, GFP_KERNEL);
 237         if (!buffer)
 238                 return -ENOMEM;
 239
 240         /* expect two bytes 0x27 0x00 */
 241         r = ch341_control_in(dev, CH341_REQ_READ_VERSION, 0, 0, buffer, size);
 242         if (r < 0)
 243                 goto out;
 244
 245         r = ch341_control_out(dev, CH341_REQ_SERIAL_INIT, 0, 0);
 246         if (r < 0)
 247                 goto out;
 248
 249         /* expect two bytes 0x56 0x00 */
 250         r = ch341_control_in(dev, CH341_REQ_READ_REG, 0x2518, 0, buffer, size);
 251         if (r < 0)
 252                 goto out;
 253
 254         r = ch341_control_out(dev, CH341_REQ_WRITE_REG, 0x2518, 0x0050);
 255         if (r < 0)
 256                 goto out;
 257
 258         /* expect 0xff 0xee */
 259         r = ch341_get_status(dev, priv);
 260         if (r < 0)
 261                 goto out;
 262
 263         r = ch341_set_baudrate_lcr(dev, priv, 0);
 264         if (r < 0)
 265                 goto out;
 266
 267         r = ch341_set_handshake(dev, priv->line_control);
 268         if (r < 0)
 269                 goto out;
 270
 271         /* expect 0x9f 0xee */
 272         r = ch341_get_status(dev, priv);
 273
 274 out:    kfree(buffer);
 275         return r;
 276 }
 277
 278 /* allocate private data */
 279 static int ch341_attach(struct usb_serial *serial)
 280 {
 281         struct ch341_private *priv;
 282         int r;
 283
 284         dbg("ch341_attach()");
 285
 286         /* private data */
 287         priv = kzalloc(sizeof(struct ch341_private), GFP_KERNEL);
 288         if (!priv)
 289                 return -ENOMEM;
 290
 291         spin_lock_init(&priv->lock);
 292         priv->baud_rate = DEFAULT_BAUD_RATE;
 293
 294         r = ch341_configure(serial->dev, priv);
 295         if (r < 0)
 296                 goto error;
 297
 298         usb_set_serial_port_data(serial->port[0], priv);
 299         return 0;
 300
 301 error:  kfree(priv);
 302         return r;
 303 }
 304
 305 static int ch341_carrier_raised(struct usb_serial_port *port)
 306 {
 307         struct ch341_private *priv = usb_get_serial_port_data(port);
 308         if (priv->line_status & CH341_BIT_DCD)
 309                 return 1;
 310         return 0;
 311 }
 312
 313 static void ch341_dtr_rts(struct usb_serial_port *port, int on)
 314 {
 315         struct ch341_private *priv = usb_get_serial_port_data(port);
 316         unsigned long flags;
 317
 318         dbg("%s - port %d", __func__, port->number);
 319         /* drop DTR and RTS */
 320         spin_lock_irqsave(&priv->lock, flags);
 321         if (on)
 322                 priv->line_control |= CH341_BIT_RTS | CH341_BIT_DTR;
 323         else
 324                 priv->line_control &= ~(CH341_BIT_RTS | CH341_BIT_DTR);
 325         spin_unlock_irqrestore(&priv->lock, flags);
 326         ch341_set_handshake(port->serial->dev, priv->line_control);
 327         wake_up_interruptible(&port->delta_msr_wait);
 328 }
 329
 330 static void ch341_close(struct usb_serial_port *port)
 331 {
 332         dbg("%s - port %d", __func__, port->number);
 333
 334         usb_serial_generic_close(port);
 335         usb_kill_urb(port->interrupt_in_urb);
 336 }
 337
 338
 339 /* open this device, set default parameters */
 340 static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port)
 341 {
 342         struct usb_serial *serial = port->serial;
 343         struct ch341_private *priv = usb_get_serial_port_data(serial->port[0]);
 344         int r;
 345
 346         dbg("ch341_open()");
 347
 348         r = ch341_configure(serial->dev, priv);
 349         if (r)
 350                 return r;
 351
 352         if (tty)
 353                 ch341_set_termios(tty, port, NULL);
 354
 355         dbg("%s - submitting interrupt urb", __func__);
 356         port->interrupt_in_urb->dev = serial->dev;
 357         r = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
 358         if (r) {
 359                 dev_err(&port->dev, "%s - failed submitting interrupt urb,"
 360                         " error %d\n", __func__, r);
 361                 return r;
 362         }
 363
 364         r = usb_serial_generic_open(tty, port);
 365         if (r)
 366                 goto err_kill_interrupt_urb;
 367
 368         return 0;
 369
 370 err_kill_interrupt_urb:
 371         usb_kill_urb(port->interrupt_in_urb);
 372
 373         return r;
 374 }
 375
 376 /* Old_termios contains the original termios settings and
 377  * tty->termios contains the new setting to be used.
 378  */
 379 static void ch341_set_termios(struct tty_struct *tty,
 380                 struct usb_serial_port *port, struct ktermios *old_termios)
 381 {
 382         struct ch341_private *priv = usb_get_serial_port_data(port);
 383         unsigned baud_rate;
 384         unsigned long flags;
 385         unsigned char ctrl;
 386         int r;
 387
 388         /* redundant changes may cause the chip to lose bytes */
 389         if (old_termios && !tty_termios_hw_change(tty->termios, old_termios))
 390                 return;
 391
 392         dbg("ch341_set_termios()");
 393
 394         baud_rate = tty_get_baud_rate(tty);
 395
 396         ctrl = CH341_LCR_ENABLE_RX | CH341_LCR_ENABLE_TX | CH341_LCR_CS8;
 397
 398         if (baud_rate) {
 399                 priv->baud_rate = baud_rate;
 400
 401                 r = ch341_set_baudrate_lcr(port->serial->dev, priv, ctrl);
 402                 if (r < 0 && old_termios) {
 403                         priv->baud_rate = tty_termios_baud_rate(old_termios);
 404                         tty_termios_copy_hw(tty->termios, old_termios);
 405                 }
 406         }
 407
 408         spin_lock_irqsave(&priv->lock, flags);
 409         if (C_BAUD(tty) == B0)
 410                 priv->line_control &= ~(CH341_BIT_DTR | CH341_BIT_RTS);
 411         else if (old_termios && (old_termios->c_cflag & CBAUD) == B0)
 412                 priv->line_control |= (CH341_BIT_DTR | CH341_BIT_RTS);
 413         spin_unlock_irqrestore(&priv->lock, flags);
 414
 415         /* Unimplemented:
 416          * (cflag & CSIZE) : data bits [5, 8]
 417          * (cflag & PARENB) : parity {NONE, EVEN, ODD}
 418          * (cflag & CSTOPB) : stop bits [1, 2]
 419          */
 420 }
 421
 422 static void ch341_break_ctl(struct tty_struct *tty, int break_state)
 423 {
 424         const uint16_t ch341_break_reg =
 425                         ((uint16_t) CH341_REG_LCR << 8) | CH341_REG_BREAK;
 426         struct usb_serial_port *port = tty->driver_data;
 427         int r;
 428         uint16_t reg_contents;
 429         uint8_t *break_reg;
 430
 431         dbg("%s()", __func__);
 432
 433         break_reg = kmalloc(2, GFP_KERNEL);
 434         if (!break_reg) {
 435                 dev_err(&port->dev, "%s - kmalloc failed\n", __func__);
 436                 return;
 437         }
 438
 439         r = ch341_control_in(port->serial->dev, CH341_REQ_READ_REG,
 440                         ch341_break_reg, 0, break_reg, 2);
 441         if (r < 0) {
 442                 dev_err(&port->dev, "%s - USB control read error (%d)\n",
 443                                 __func__, r);
 444                 goto out;
 445         }
 446         dbg("%s - initial ch341 break register contents - reg1: %x, reg2: %x",
 447                         __func__, break_reg[0], break_reg[1]);
 448         if (break_state != 0) {
 449                 dbg("%s - Enter break state requested", __func__);
 450                 break_reg[0] &= ~CH341_NBREAK_BITS;
 451                 break_reg[1] &= ~CH341_LCR_ENABLE_TX;
 452         } else {
 453                 dbg("%s - Leave break state requested", __func__);
 454                 break_reg[0] |= CH341_NBREAK_BITS;
 455                 break_reg[1] |= CH341_LCR_ENABLE_TX;
 456         }
 457         dbg("%s - New ch341 break register contents - reg1: %x, reg2: %x",
 458                         __func__, break_reg[0], break_reg[1]);
 459         reg_contents = get_unaligned_le16(break_reg);
 460         r = ch341_control_out(port->serial->dev, CH341_REQ_WRITE_REG,
 461                         ch341_break_reg, reg_contents);
 462         if (r < 0)
 463                 dev_err(&port->dev, "%s - USB control write error (%d)\n",
 464                                 __func__, r);
 465 out:
 466         kfree(break_reg);
 467 }
 468
 469 static int ch341_tiocmset(struct tty_struct *tty,
 470                           unsigned int set, unsigned int clear)
 471 {
 472         struct usb_serial_port *port = tty->driver_data;
 473         struct ch341_private *priv = usb_get_serial_port_data(port);
 474         unsigned long flags;
 475         u8 control;
 476
 477         spin_lock_irqsave(&priv->lock, flags);
 478         if (set & TIOCM_RTS)
 479                 priv->line_control |= CH341_BIT_RTS;
 480         if (set & TIOCM_DTR)
 481                 priv->line_control |= CH341_BIT_DTR;
 482         if (clear & TIOCM_RTS)
 483                 priv->line_control &= ~CH341_BIT_RTS;
 484         if (clear & TIOCM_DTR)
 485                 priv->line_control &= ~CH341_BIT_DTR;
 486         control = priv->line_control;
 487         spin_unlock_irqrestore(&priv->lock, flags);
 488
 489         return ch341_set_handshake(port->serial->dev, control);
 490 }
 491
 492 static void ch341_read_int_callback(struct urb *urb)
 493 {
 494         struct usb_serial_port *port = (struct usb_serial_port *) urb->context;
 495         unsigned char *data = urb->transfer_buffer;
 496         unsigned int actual_length = urb->actual_length;
 497         int status;
 498
 499         dbg("%s (%d)", __func__, port->number);
 500
 501         switch (urb->status) {
 502         case 0:
 503                 /* success */
 504                 break;
 505         case -ECONNRESET:
 506         case -ENOENT:
 507         case -ESHUTDOWN:
 508                 /* this urb is terminated, clean up */
 509                 dbg("%s - urb shutting down with status: %d", __func__,
 510                     urb->status);
 511                 return;
 512         default:
 513                 dbg("%s - nonzero urb status received: %d", __func__,
 514                     urb->status);
 515                 goto exit;
 516         }
 517
 518         usb_serial_debug_data(debug, &port->dev, __func__,
 519                               urb->actual_length, urb->transfer_buffer);
 520
 521         if (actual_length >= 4) {
 522                 struct ch341_private *priv = usb_get_serial_port_data(port);
 523                 unsigned long flags;
 524                 u8 prev_line_status = priv->line_status;
 525
 526                 spin_lock_irqsave(&priv->lock, flags);
 527                 priv->line_status = (~(data[2])) & CH341_BITS_MODEM_STAT;
 528                 if ((data[1] & CH341_MULT_STAT))
 529                         priv->multi_status_change = 1;
 530                 spin_unlock_irqrestore(&priv->lock, flags);
 531
 532                 if ((priv->line_status ^ prev_line_status) & CH341_BIT_DCD) {
 533                         struct tty_struct *tty = tty_port_tty_get(&port->port);
 534                         if (tty)
 535                                 usb_serial_handle_dcd_change(port, tty,
 536                                             priv->line_status & CH341_BIT_DCD);
 537                         tty_kref_put(tty);
 538                 }
 539
 540                 wake_up_interruptible(&port->delta_msr_wait);
 541         }
 542
 543 exit:
 544         status = usb_submit_urb(urb, GFP_ATOMIC);
 545         if (status)
 546                 dev_err(&urb->dev->dev,
 547                         "%s - usb_submit_urb failed with result %d\n",
 548                         __func__, status);
 549 }
 550
 551 static int wait_modem_info(struct usb_serial_port *port, unsigned int arg)
 552 {
 553         struct ch341_private *priv = usb_get_serial_port_data(port);
 554         unsigned long flags;
 555         u8 prevstatus;
 556         u8 status;
 557         u8 changed;
 558         u8 multi_change = 0;
 559
 560         spin_lock_irqsave(&priv->lock, flags);
 561         prevstatus = priv->line_status;
 562         priv->multi_status_change = 0;
 563         spin_unlock_irqrestore(&priv->lock, flags);
 564
 565         while (!multi_change) {
 566                 interruptible_sleep_on(&port->delta_msr_wait);
 567                 /* see if a signal did it */
 568                 if (signal_pending(current))
 569                         return -ERESTARTSYS;
 570
 571                 if (port->serial->disconnected)
 572                         return -EIO;
 573
 574                 spin_lock_irqsave(&priv->lock, flags);
 575                 status = priv->line_status;
 576                 multi_change = priv->multi_status_change;
 577                 spin_unlock_irqrestore(&priv->lock, flags);
 578
 579                 changed = prevstatus ^ status;
 580
 581                 if (((arg & TIOCM_RNG) && (changed & CH341_BIT_RI)) ||
 582                     ((arg & TIOCM_DSR) && (changed & CH341_BIT_DSR)) ||
 583                     ((arg & TIOCM_CD)  && (changed & CH341_BIT_DCD)) ||
 584                     ((arg & TIOCM_CTS) && (changed & CH341_BIT_CTS))) {
 585                         return 0;
 586                 }
 587                 prevstatus = status;
 588         }
 589
 590         return 0;
 591 }
 592
 593 static int ch341_ioctl(struct tty_struct *tty,
 594                         unsigned int cmd, unsigned long arg)
 595 {
 596         struct usb_serial_port *port = tty->driver_data;
 597         dbg("%s (%d) cmd = 0x%04x", __func__, port->number, cmd);
 598
 599         switch (cmd) {
 600         case TIOCMIWAIT:
 601                 dbg("%s (%d) TIOCMIWAIT", __func__,  port->number);
 602                 return wait_modem_info(port, arg);
 603
 604         default:
 605                 dbg("%s not supported = 0x%04x", __func__, cmd);
 606                 break;
 607         }
 608
 609         return -ENOIOCTLCMD;
 610 }
 611
 612 static int ch341_tiocmget(struct tty_struct *tty)
 613 {
 614         struct usb_serial_port *port = tty->driver_data;
 615         struct ch341_private *priv = usb_get_serial_port_data(port);
 616         unsigned long flags;
 617         u8 mcr;
 618         u8 status;
 619         unsigned int result;
 620
 621         dbg("%s (%d)", __func__, port->number);
 622
 623         spin_lock_irqsave(&priv->lock, flags);
 624         mcr = priv->line_control;
 625         status = priv->line_status;
 626         spin_unlock_irqrestore(&priv->lock, flags);
 627
 628         result = ((mcr & CH341_BIT_DTR)         ? TIOCM_DTR : 0)
 629                   | ((mcr & CH341_BIT_RTS)      ? TIOCM_RTS : 0)
 630                   | ((status & CH341_BIT_CTS)   ? TIOCM_CTS : 0)
 631                   | ((status & CH341_BIT_DSR)   ? TIOCM_DSR : 0)
 632                   | ((status & CH341_BIT_RI)    ? TIOCM_RI  : 0)
 633                   | ((status & CH341_BIT_DCD)   ? TIOCM_CD  : 0);
 634
 635         dbg("%s - result = %x", __func__, result);
 636
 637         return result;
 638 }
 639
 640
 641 static int ch341_reset_resume(struct usb_interface *intf)
 642 {
 643         struct usb_device *dev = interface_to_usbdev(intf);
 644         struct usb_serial *serial = usb_get_intfdata(intf);
 645         struct usb_serial_port *port = serial->port[0];
 646         struct ch341_private *priv = usb_get_serial_port_data(port);
 647         int ret;
 648
 649         /*reconfigure ch341 serial port after bus-reset*/
 650         ch341_configure(dev, priv);
 651
 652         if (port->port.flags & ASYNC_INITIALIZED) {
 653                 ret = usb_submit_urb(port->interrupt_in_urb, GFP_NOIO);
 654                 if (ret) {
 655                         dev_err(&port->dev, "failed to submit interrupt urb: %d\n",
 656                                 ret);
 657                         return ret;
 658                 }
 659         }
 660
 661         return usb_serial_generic_resume(serial);
 662 }
 663
 664 static struct usb_driver ch341_driver = {
 665         .name           = "ch341",
 666         .probe          = usb_serial_probe,
 667         .disconnect     = usb_serial_disconnect,
 668         .suspend        = usb_serial_suspend,
 669         .resume         = usb_serial_resume,
 670         .reset_resume   = ch341_reset_resume,
 671         .id_table       = id_table,
 672         .no_dynamic_id  = 1,
 673         .supports_autosuspend = 1,
 674 };
 675
 676 static struct usb_serial_driver ch341_device = {
 677         .driver = {
 678                 .owner  = THIS_MODULE,
 679                 .name   = "ch341-uart",
 680         },
 681         .id_table          = id_table,
 682         .usb_driver        = &ch341_driver,
 683         .num_ports         = 1,
 684         .open              = ch341_open,
 685         .dtr_rts           = ch341_dtr_rts,
 686         .carrier_raised    = ch341_carrier_raised,
 687         .close             = ch341_close,
 688         .ioctl             = ch341_ioctl,
 689         .set_termios       = ch341_set_termios,
 690         .break_ctl         = ch341_break_ctl,
 691         .tiocmget          = ch341_tiocmget,
 692         .tiocmset          = ch341_tiocmset,
 693         .read_int_callback = ch341_read_int_callback,
 694         .attach            = ch341_attach,
 695 };
 696
 697 static int __init ch341_init(void)
 698 {
 699         int retval;
 700
 701         retval = usb_serial_register(&ch341_device);
 702         if (retval)
 703                 return retval;
 704         retval = usb_register(&ch341_driver);
 705         if (retval)
 706                 usb_serial_deregister(&ch341_device);
 707         return retval;
 708 }
 709
 710 static void __exit ch341_exit(void)
 711 {
 712         usb_deregister(&ch341_driver);
 713         usb_serial_deregister(&ch341_device);
 714 }
 715
 716 module_init(ch341_init);
 717 module_exit(ch341_exit);
 718 MODULE_LICENSE("GPL");
 719
 720 module_param(debug, bool, S_IRUGO | S_IWUSR);
 721 MODULE_PARM_DESC(debug, "Debug enabled or not");
 722
 723 /* EOF ch341.c */