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         r = ch341_set_baudrate_lcr(dev, priv, 0);
 259         if (r < 0)
 260                 goto out;
 261
 262         r = ch341_set_handshake(dev, priv->line_control);
 263
 264 out:    kfree(buffer);
 265         return r;
 266 }
 267
 268 /* allocate private data */
 269 static int ch341_attach(struct usb_serial *serial)
 270 {
 271         struct ch341_private *priv;
 272         int r;
 273
 274         dbg("ch341_attach()");
 275
 276         /* private data */
 277         priv = kzalloc(sizeof(struct ch341_private), GFP_KERNEL);
 278         if (!priv)
 279                 return -ENOMEM;
 280
 281         spin_lock_init(&priv->lock);
 282         priv->baud_rate = DEFAULT_BAUD_RATE;
 283
 284         r = ch341_configure(serial->dev, priv);
 285         if (r < 0)
 286                 goto error;
 287
 288         usb_set_serial_port_data(serial->port[0], priv);
 289         return 0;
 290
 291 error:  kfree(priv);
 292         return r;
 293 }
 294
 295 static int ch341_carrier_raised(struct usb_serial_port *port)
 296 {
 297         struct ch341_private *priv = usb_get_serial_port_data(port);
 298         if (priv->line_status & CH341_BIT_DCD)
 299                 return 1;
 300         return 0;
 301 }
 302
 303 static void ch341_dtr_rts(struct usb_serial_port *port, int on)
 304 {
 305         struct ch341_private *priv = usb_get_serial_port_data(port);
 306         unsigned long flags;
 307
 308         dbg("%s - port %d", __func__, port->number);
 309         /* drop DTR and RTS */
 310         spin_lock_irqsave(&priv->lock, flags);
 311         if (on)
 312                 priv->line_control |= CH341_BIT_RTS | CH341_BIT_DTR;
 313         else
 314                 priv->line_control &= ~(CH341_BIT_RTS | CH341_BIT_DTR);
 315         spin_unlock_irqrestore(&priv->lock, flags);
 316         ch341_set_handshake(port->serial->dev, priv->line_control);
 317         wake_up_interruptible(&port->delta_msr_wait);
 318 }
 319
 320 static void ch341_close(struct usb_serial_port *port)
 321 {
 322         dbg("%s - port %d", __func__, port->number);
 323
 324         usb_serial_generic_close(port);
 325         usb_kill_urb(port->interrupt_in_urb);
 326 }
 327
 328
 329 /* open this device, set default parameters */
 330 static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port)
 331 {
 332         struct usb_serial *serial = port->serial;
 333         struct ch341_private *priv = usb_get_serial_port_data(serial->port[0]);
 334         int r;
 335
 336         dbg("ch341_open()");
 337
 338         if (tty)
 339                 ch341_set_termios(tty, port, NULL);
 340
 341         dbg("%s - submitting interrupt urb", __func__);
 342         port->interrupt_in_urb->dev = serial->dev;
 343         r = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
 344         if (r) {
 345                 dev_err(&port->dev, "%s - failed submitting interrupt urb,"
 346                         " error %d\n", __func__, r);
 347                 return r;
 348         }
 349
 350         r = ch341_get_status(port->serial->dev, priv);
 351         if (r < 0) {
 352                 dev_err(&port->dev, "failed to read modem status: %d\n", r);
 353                 goto err_kill_interrupt_urb;
 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         dbg("ch341_set_termios()");
 385
 386         baud_rate = tty_get_baud_rate(tty);
 387
 388         ctrl = CH341_LCR_ENABLE_RX | CH341_LCR_ENABLE_TX | CH341_LCR_CS8;
 389
 390         if (baud_rate) {
 391                 priv->baud_rate = baud_rate;
 392
 393                 r = ch341_set_baudrate_lcr(port->serial->dev, priv, ctrl);
 394                 if (r < 0 && old_termios) {
 395                         priv->baud_rate = tty_termios_baud_rate(old_termios);
 396                         tty_termios_copy_hw(tty->termios, old_termios);
 397                 }
 398         }
 399
 400         spin_lock_irqsave(&priv->lock, flags);
 401         if (C_BAUD(tty) == B0)
 402                 priv->line_control &= ~(CH341_BIT_DTR | CH341_BIT_RTS);
 403         else if (old_termios && (old_termios->c_cflag & CBAUD) == B0)
 404                 priv->line_control |= (CH341_BIT_DTR | CH341_BIT_RTS);
 405         spin_unlock_irqrestore(&priv->lock, flags);
 406
 407         /* Unimplemented:
 408          * (cflag & CSIZE) : data bits [5, 8]
 409          * (cflag & PARENB) : parity {NONE, EVEN, ODD}
 410          * (cflag & CSTOPB) : stop bits [1, 2]
 411          */
 412 }
 413
 414 static void ch341_break_ctl(struct tty_struct *tty, int break_state)
 415 {
 416         const uint16_t ch341_break_reg =
 417                         ((uint16_t) CH341_REG_LCR << 8) | CH341_REG_BREAK;
 418         struct usb_serial_port *port = tty->driver_data;
 419         int r;
 420         uint16_t reg_contents;
 421         uint8_t *break_reg;
 422
 423         dbg("%s()", __func__);
 424
 425         break_reg = kmalloc(2, GFP_KERNEL);
 426         if (!break_reg) {
 427                 dev_err(&port->dev, "%s - kmalloc failed\n", __func__);
 428                 return;
 429         }
 430
 431         r = ch341_control_in(port->serial->dev, CH341_REQ_READ_REG,
 432                         ch341_break_reg, 0, break_reg, 2);
 433         if (r < 0) {
 434                 dev_err(&port->dev, "%s - USB control read error (%d)\n",
 435                                 __func__, r);
 436                 goto out;
 437         }
 438         dbg("%s - initial ch341 break register contents - reg1: %x, reg2: %x",
 439                         __func__, break_reg[0], break_reg[1]);
 440         if (break_state != 0) {
 441                 dbg("%s - Enter break state requested", __func__);
 442                 break_reg[0] &= ~CH341_NBREAK_BITS;
 443                 break_reg[1] &= ~CH341_LCR_ENABLE_TX;
 444         } else {
 445                 dbg("%s - Leave break state requested", __func__);
 446                 break_reg[0] |= CH341_NBREAK_BITS;
 447                 break_reg[1] |= CH341_LCR_ENABLE_TX;
 448         }
 449         dbg("%s - New ch341 break register contents - reg1: %x, reg2: %x",
 450                         __func__, break_reg[0], break_reg[1]);
 451         reg_contents = get_unaligned_le16(break_reg);
 452         r = ch341_control_out(port->serial->dev, CH341_REQ_WRITE_REG,
 453                         ch341_break_reg, reg_contents);
 454         if (r < 0)
 455                 dev_err(&port->dev, "%s - USB control write error (%d)\n",
 456                                 __func__, r);
 457 out:
 458         kfree(break_reg);
 459 }
 460
 461 static int ch341_tiocmset(struct tty_struct *tty,
 462                           unsigned int set, unsigned int clear)
 463 {
 464         struct usb_serial_port *port = tty->driver_data;
 465         struct ch341_private *priv = usb_get_serial_port_data(port);
 466         unsigned long flags;
 467         u8 control;
 468
 469         spin_lock_irqsave(&priv->lock, flags);
 470         if (set & TIOCM_RTS)
 471                 priv->line_control |= CH341_BIT_RTS;
 472         if (set & TIOCM_DTR)
 473                 priv->line_control |= CH341_BIT_DTR;
 474         if (clear & TIOCM_RTS)
 475                 priv->line_control &= ~CH341_BIT_RTS;
 476         if (clear & TIOCM_DTR)
 477                 priv->line_control &= ~CH341_BIT_DTR;
 478         control = priv->line_control;
 479         spin_unlock_irqrestore(&priv->lock, flags);
 480
 481         return ch341_set_handshake(port->serial->dev, control);
 482 }
 483
 484 static void ch341_read_int_callback(struct urb *urb)
 485 {
 486         struct usb_serial_port *port = (struct usb_serial_port *) urb->context;
 487         unsigned char *data = urb->transfer_buffer;
 488         unsigned int actual_length = urb->actual_length;
 489         int status;
 490
 491         dbg("%s (%d)", __func__, port->number);
 492
 493         switch (urb->status) {
 494         case 0:
 495                 /* success */
 496                 break;
 497         case -ECONNRESET:
 498         case -ENOENT:
 499         case -ESHUTDOWN:
 500                 /* this urb is terminated, clean up */
 501                 dbg("%s - urb shutting down with status: %d", __func__,
 502                     urb->status);
 503                 return;
 504         default:
 505                 dbg("%s - nonzero urb status received: %d", __func__,
 506                     urb->status);
 507                 goto exit;
 508         }
 509
 510         usb_serial_debug_data(debug, &port->dev, __func__,
 511                               urb->actual_length, urb->transfer_buffer);
 512
 513         if (actual_length >= 4) {
 514                 struct ch341_private *priv = usb_get_serial_port_data(port);
 515                 unsigned long flags;
 516                 u8 prev_line_status = priv->line_status;
 517
 518                 spin_lock_irqsave(&priv->lock, flags);
 519                 priv->line_status = (~(data[2])) & CH341_BITS_MODEM_STAT;
 520                 if ((data[1] & CH341_MULT_STAT))
 521                         priv->multi_status_change = 1;
 522                 spin_unlock_irqrestore(&priv->lock, flags);
 523
 524                 if ((priv->line_status ^ prev_line_status) & CH341_BIT_DCD) {
 525                         struct tty_struct *tty = tty_port_tty_get(&port->port);
 526                         if (tty)
 527                                 usb_serial_handle_dcd_change(port, tty,
 528                                             priv->line_status & CH341_BIT_DCD);
 529                         tty_kref_put(tty);
 530                 }
 531
 532                 wake_up_interruptible(&port->delta_msr_wait);
 533         }
 534
 535 exit:
 536         status = usb_submit_urb(urb, GFP_ATOMIC);
 537         if (status)
 538                 dev_err(&urb->dev->dev,
 539                         "%s - usb_submit_urb failed with result %d\n",
 540                         __func__, status);
 541 }
 542
 543 static int wait_modem_info(struct usb_serial_port *port, unsigned int arg)
 544 {
 545         struct ch341_private *priv = usb_get_serial_port_data(port);
 546         unsigned long flags;
 547         u8 prevstatus;
 548         u8 status;
 549         u8 changed;
 550         u8 multi_change = 0;
 551
 552         spin_lock_irqsave(&priv->lock, flags);
 553         prevstatus = priv->line_status;
 554         priv->multi_status_change = 0;
 555         spin_unlock_irqrestore(&priv->lock, flags);
 556
 557         while (!multi_change) {
 558                 interruptible_sleep_on(&port->delta_msr_wait);
 559                 /* see if a signal did it */
 560                 if (signal_pending(current))
 561                         return -ERESTARTSYS;
 562
 563                 if (port->serial->disconnected)
 564                         return -EIO;
 565
 566                 spin_lock_irqsave(&priv->lock, flags);
 567                 status = priv->line_status;
 568                 multi_change = priv->multi_status_change;
 569                 spin_unlock_irqrestore(&priv->lock, flags);
 570
 571                 changed = prevstatus ^ status;
 572
 573                 if (((arg & TIOCM_RNG) && (changed & CH341_BIT_RI)) ||
 574                     ((arg & TIOCM_DSR) && (changed & CH341_BIT_DSR)) ||
 575                     ((arg & TIOCM_CD)  && (changed & CH341_BIT_DCD)) ||
 576                     ((arg & TIOCM_CTS) && (changed & CH341_BIT_CTS))) {
 577                         return 0;
 578                 }
 579                 prevstatus = status;
 580         }
 581
 582         return 0;
 583 }
 584
 585 static int ch341_ioctl(struct tty_struct *tty,
 586                         unsigned int cmd, unsigned long arg)
 587 {
 588         struct usb_serial_port *port = tty->driver_data;
 589         dbg("%s (%d) cmd = 0x%04x", __func__, port->number, cmd);
 590
 591         switch (cmd) {
 592         case TIOCMIWAIT:
 593                 dbg("%s (%d) TIOCMIWAIT", __func__,  port->number);
 594                 return wait_modem_info(port, arg);
 595
 596         default:
 597                 dbg("%s not supported = 0x%04x", __func__, cmd);
 598                 break;
 599         }
 600
 601         return -ENOIOCTLCMD;
 602 }
 603
 604 static int ch341_tiocmget(struct tty_struct *tty)
 605 {
 606         struct usb_serial_port *port = tty->driver_data;
 607         struct ch341_private *priv = usb_get_serial_port_data(port);
 608         unsigned long flags;
 609         u8 mcr;
 610         u8 status;
 611         unsigned int result;
 612
 613         dbg("%s (%d)", __func__, port->number);
 614
 615         spin_lock_irqsave(&priv->lock, flags);
 616         mcr = priv->line_control;
 617         status = priv->line_status;
 618         spin_unlock_irqrestore(&priv->lock, flags);
 619
 620         result = ((mcr & CH341_BIT_DTR)         ? TIOCM_DTR : 0)
 621                   | ((mcr & CH341_BIT_RTS)      ? TIOCM_RTS : 0)
 622                   | ((status & CH341_BIT_CTS)   ? TIOCM_CTS : 0)
 623                   | ((status & CH341_BIT_DSR)   ? TIOCM_DSR : 0)
 624                   | ((status & CH341_BIT_RI)    ? TIOCM_RI  : 0)
 625                   | ((status & CH341_BIT_DCD)   ? TIOCM_CD  : 0);
 626
 627         dbg("%s - result = %x", __func__, result);
 628
 629         return result;
 630 }
 631
 632
 633 static int ch341_reset_resume(struct usb_interface *intf)
 634 {
 635         struct usb_device *dev = interface_to_usbdev(intf);
 636         struct usb_serial *serial = usb_get_intfdata(intf);
 637         struct usb_serial_port *port = serial->port[0];
 638         struct ch341_private *priv = usb_get_serial_port_data(port);
 639         int ret;
 640
 641         /*reconfigure ch341 serial port after bus-reset*/
 642         ch341_configure(dev, priv);
 643
 644         if (port->port.flags & ASYNC_INITIALIZED) {
 645                 ret = usb_submit_urb(port->interrupt_in_urb, GFP_NOIO);
 646                 if (ret) {
 647                         dev_err(&port->dev, "failed to submit interrupt urb: %d\n",
 648                                 ret);
 649                         return ret;
 650                 }
 651
 652                 ret = ch341_get_status(port->serial->dev, priv);
 653                 if (ret < 0) {
 654                         dev_err(&port->dev, "failed to read modem status: %d\n",
 655                                 ret);
 656                 }
 657         }
 658
 659         return usb_serial_generic_resume(serial);
 660 }
 661
 662 static struct usb_driver ch341_driver = {
 663         .name           = "ch341",
 664         .probe          = usb_serial_probe,
 665         .disconnect     = usb_serial_disconnect,
 666         .suspend        = usb_serial_suspend,
 667         .resume         = usb_serial_resume,
 668         .reset_resume   = ch341_reset_resume,
 669         .id_table       = id_table,
 670         .no_dynamic_id  = 1,
 671         .supports_autosuspend = 1,
 672 };
 673
 674 static struct usb_serial_driver ch341_device = {
 675         .driver = {
 676                 .owner  = THIS_MODULE,
 677                 .name   = "ch341-uart",
 678         },
 679         .id_table          = id_table,
 680         .usb_driver        = &ch341_driver,
 681         .num_ports         = 1,
 682         .open              = ch341_open,
 683         .dtr_rts           = ch341_dtr_rts,
 684         .carrier_raised    = ch341_carrier_raised,
 685         .close             = ch341_close,
 686         .ioctl             = ch341_ioctl,
 687         .set_termios       = ch341_set_termios,
 688         .break_ctl         = ch341_break_ctl,
 689         .tiocmget          = ch341_tiocmget,
 690         .tiocmset          = ch341_tiocmset,
 691         .read_int_callback = ch341_read_int_callback,
 692         .attach            = ch341_attach,
 693 };
 694
 695 static int __init ch341_init(void)
 696 {
 697         int retval;
 698
 699         retval = usb_serial_register(&ch341_device);
 700         if (retval)
 701                 return retval;
 702         retval = usb_register(&ch341_driver);
 703         if (retval)
 704                 usb_serial_deregister(&ch341_device);
 705         return retval;
 706 }
 707
 708 static void __exit ch341_exit(void)
 709 {
 710         usb_deregister(&ch341_driver);
 711         usb_serial_deregister(&ch341_device);
 712 }
 713
 714 module_init(ch341_init);
 715 module_exit(ch341_exit);
 716 MODULE_LICENSE("GPL");
 717
 718 module_param(debug, bool, S_IRUGO | S_IWUSR);
 719 MODULE_PARM_DESC(debug, "Debug enabled or not");
 720
 721 /* EOF ch341.c */