drivers/usb/serial/ark3116.c

   1 /*
   2  * Copyright (C) 2009 by Bart Hartgers (bart.hartgers+ark3116@gmail.com)
   3  * Original version:
   4  * Copyright (C) 2006
   5  *   Simon Schulz (ark3116_driver <at> auctionant.de)
   6  *
   7  * ark3116
   8  * - implements a driver for the arkmicro ark3116 chipset (vendor=0x6547,
   9  *   productid=0x0232) (used in a datacable called KQ-U8A)
  10  *
  11  * Supports full modem status lines, break, hardware flow control. Does not
  12  * support software flow control, since I do not know how to enable it in hw.
  13  *
  14  * This driver is a essentially new implementation. I initially dug
  15  * into the old ark3116.c driver and suddenly realized the ark3116 is
  16  * a 16450 with a USB interface glued to it. See comments at the
  17  * bottom of this file.
  18  *
  19  * This program is free software; you can redistribute it and/or modify it
  20  * under the terms of the GNU General Public License as published by the
  21  * Free Software Foundation; either version 2 of the License, or (at your
  22  * option) any later version.
  23  */
  24
  25 #include <linux/kernel.h>
  26 #include <linux/init.h>
  27 #include <linux/ioctl.h>
  28 #include <linux/tty.h>
  29 #include <linux/slab.h>
  30 #include <linux/tty_flip.h>
  31 #include <linux/module.h>
  32 #include <linux/usb.h>
  33 #include <linux/usb/serial.h>
  34 #include <linux/serial.h>
  35 #include <linux/serial_reg.h>
  36 #include <linux/uaccess.h>
  37 #include <linux/mutex.h>
  38 #include <linux/spinlock.h>
  39
  40 #define DRIVER_AUTHOR "Bart Hartgers <bart.hartgers+ark3116@gmail.com>"
  41 #define DRIVER_DESC "USB ARK3116 serial/IrDA driver"
  42 #define DRIVER_DEV_DESC "ARK3116 RS232/IrDA"
  43 #define DRIVER_NAME "ark3116"
  44
  45 /* usb timeout of 1 second */
  46 #define ARK_TIMEOUT (1*HZ)
  47
  48 static const struct usb_device_id id_table[] = {
  49         { USB_DEVICE(0x6547, 0x0232) },
  50         { USB_DEVICE(0x18ec, 0x3118) },         /* USB to IrDA adapter */
  51         { },
  52 };
  53 MODULE_DEVICE_TABLE(usb, id_table);
  54
  55 static int is_irda(struct usb_serial *serial)
  56 {
  57         struct usb_device *dev = serial->dev;
  58         if (le16_to_cpu(dev->descriptor.idVendor) == 0x18ec &&
  59                         le16_to_cpu(dev->descriptor.idProduct) == 0x3118)
  60                 return 1;
  61         return 0;
  62 }
  63
  64 struct ark3116_private {
  65         wait_queue_head_t       delta_msr_wait;
  66         struct async_icount     icount;
  67         int                     irda;   /* 1 for irda device */
  68
  69         /* protects hw register updates */
  70         struct mutex            hw_lock;
  71
  72         int                     quot;   /* baudrate divisor */
  73         __u32                   lcr;    /* line control register value */
  74         __u32                   hcr;    /* handshake control register (0x8)
  75                                          * value */
  76         __u32                   mcr;    /* modem contol register value */
  77
  78         /* protects the status values below */
  79         spinlock_t              status_lock;
  80         __u32                   msr;    /* modem status register value */
  81         __u32                   lsr;    /* line status register value */
  82 };
  83
  84 static int ark3116_write_reg(struct usb_serial *serial,
  85                              unsigned reg, __u8 val)
  86 {
  87         int result;
  88          /* 0xfe 0x40 are magic values taken from original driver */
  89         result = usb_control_msg(serial->dev,
  90                                  usb_sndctrlpipe(serial->dev, 0),
  91                                  0xfe, 0x40, val, reg,
  92                                  NULL, 0, ARK_TIMEOUT);
  93         return result;
  94 }
  95
  96 static int ark3116_read_reg(struct usb_serial *serial,
  97                             unsigned reg, unsigned char *buf)
  98 {
  99         int result;
 100         /* 0xfe 0xc0 are magic values taken from original driver */
 101         result = usb_control_msg(serial->dev,
 102                                  usb_rcvctrlpipe(serial->dev, 0),
 103                                  0xfe, 0xc0, 0, reg,
 104                                  buf, 1, ARK_TIMEOUT);
 105         if (result < 0)
 106                 return result;
 107         else
 108                 return buf[0];
 109 }
 110
 111 static inline int calc_divisor(int bps)
 112 {
 113         /* Original ark3116 made some exceptions in rounding here
 114          * because windows did the same. Assume that is not really
 115          * necessary.
 116          * Crystal is 12MHz, probably because of USB, but we divide by 4?
 117          */
 118         return (12000000 + 2*bps) / (4*bps);
 119 }
 120
 121 static int ark3116_attach(struct usb_serial *serial)
 122 {
 123         /* make sure we have our end-points */
 124         if ((serial->num_bulk_in == 0) ||
 125             (serial->num_bulk_out == 0) ||
 126             (serial->num_interrupt_in == 0)) {
 127                 dev_err(&serial->dev->dev,
 128                         "%s - missing endpoint - "
 129                         "bulk in: %d, bulk out: %d, int in %d\n",
 130                         KBUILD_MODNAME,
 131                         serial->num_bulk_in,
 132                         serial->num_bulk_out,
 133                         serial->num_interrupt_in);
 134                 return -EINVAL;
 135         }
 136
 137         return 0;
 138 }
 139
 140 static int ark3116_port_probe(struct usb_serial_port *port)
 141 {
 142         struct usb_serial *serial = port->serial;
 143         struct ark3116_private *priv;
 144
 145         priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 146         if (!priv)
 147                 return -ENOMEM;
 148
 149         init_waitqueue_head(&priv->delta_msr_wait);
 150         mutex_init(&priv->hw_lock);
 151         spin_lock_init(&priv->status_lock);
 152
 153         priv->irda = is_irda(serial);
 154
 155         usb_set_serial_port_data(port, priv);
 156
 157         /* setup the hardware */
 158         ark3116_write_reg(serial, UART_IER, 0);
 159         /* disable DMA */
 160         ark3116_write_reg(serial, UART_FCR, 0);
 161         /* handshake control */
 162         priv->hcr = 0;
 163         ark3116_write_reg(serial, 0x8     , 0);
 164         /* modem control */
 165         priv->mcr = 0;
 166         ark3116_write_reg(serial, UART_MCR, 0);
 167
 168         if (!(priv->irda)) {
 169                 ark3116_write_reg(serial, 0xb , 0);
 170         } else {
 171                 ark3116_write_reg(serial, 0xb , 1);
 172                 ark3116_write_reg(serial, 0xc , 0);
 173                 ark3116_write_reg(serial, 0xd , 0x41);
 174                 ark3116_write_reg(serial, 0xa , 1);
 175         }
 176
 177         /* setup baudrate */
 178         ark3116_write_reg(serial, UART_LCR, UART_LCR_DLAB);
 179
 180         /* setup for 9600 8N1 */
 181         priv->quot = calc_divisor(9600);
 182         ark3116_write_reg(serial, UART_DLL, priv->quot & 0xff);
 183         ark3116_write_reg(serial, UART_DLM, (priv->quot>>8) & 0xff);
 184
 185         priv->lcr = UART_LCR_WLEN8;
 186         ark3116_write_reg(serial, UART_LCR, UART_LCR_WLEN8);
 187
 188         ark3116_write_reg(serial, 0xe, 0);
 189
 190         if (priv->irda)
 191                 ark3116_write_reg(serial, 0x9, 0);
 192
 193         dev_info(&serial->dev->dev,
 194                 "%s using %s mode\n",
 195                 KBUILD_MODNAME,
 196                 priv->irda ? "IrDA" : "RS232");
 197         return 0;
 198 }
 199
 200 static int ark3116_port_remove(struct usb_serial_port *port)
 201 {
 202         struct ark3116_private *priv = usb_get_serial_port_data(port);
 203
 204         /* device is closed, so URBs and DMA should be down */
 205         mutex_destroy(&priv->hw_lock);
 206         kfree(priv);
 207
 208         return 0;
 209 }
 210
 211 static void ark3116_init_termios(struct tty_struct *tty)
 212 {
 213         struct ktermios *termios = &tty->termios;
 214         *termios = tty_std_termios;
 215         termios->c_cflag = B9600 | CS8
 216                                       | CREAD | HUPCL | CLOCAL;
 217         termios->c_ispeed = 9600;
 218         termios->c_ospeed = 9600;
 219 }
 220
 221 static void ark3116_set_termios(struct tty_struct *tty,
 222                                 struct usb_serial_port *port,
 223                                 struct ktermios *old_termios)
 224 {
 225         struct usb_serial *serial = port->serial;
 226         struct ark3116_private *priv = usb_get_serial_port_data(port);
 227         struct ktermios *termios = &tty->termios;
 228         unsigned int cflag = termios->c_cflag;
 229         int bps = tty_get_baud_rate(tty);
 230         int quot;
 231         __u8 lcr, hcr, eval;
 232
 233         /* set data bit count */
 234         switch (cflag & CSIZE) {
 235         case CS5:
 236                 lcr = UART_LCR_WLEN5;
 237                 break;
 238         case CS6:
 239                 lcr = UART_LCR_WLEN6;
 240                 break;
 241         case CS7:
 242                 lcr = UART_LCR_WLEN7;
 243                 break;
 244         default:
 245         case CS8:
 246                 lcr = UART_LCR_WLEN8;
 247                 break;
 248         }
 249         if (cflag & CSTOPB)
 250                 lcr |= UART_LCR_STOP;
 251         if (cflag & PARENB)
 252                 lcr |= UART_LCR_PARITY;
 253         if (!(cflag & PARODD))
 254                 lcr |= UART_LCR_EPAR;
 255 #ifdef CMSPAR
 256         if (cflag & CMSPAR)
 257                 lcr |= UART_LCR_SPAR;
 258 #endif
 259         /* handshake control */
 260         hcr = (cflag & CRTSCTS) ? 0x03 : 0x00;
 261
 262         /* calc baudrate */
 263         dev_dbg(&port->dev, "%s - setting bps to %d\n", __func__, bps);
 264         eval = 0;
 265         switch (bps) {
 266         case 0:
 267                 quot = calc_divisor(9600);
 268                 break;
 269         default:
 270                 if ((bps < 75) || (bps > 3000000))
 271                         bps = 9600;
 272                 quot = calc_divisor(bps);
 273                 break;
 274         case 460800:
 275                 eval = 1;
 276                 quot = calc_divisor(bps);
 277                 break;
 278         case 921600:
 279                 eval = 2;
 280                 quot = calc_divisor(bps);
 281                 break;
 282         }
 283
 284         /* Update state: synchronize */
 285         mutex_lock(&priv->hw_lock);
 286
 287         /* keep old LCR_SBC bit */
 288         lcr |= (priv->lcr & UART_LCR_SBC);
 289
 290         dev_dbg(&port->dev, "%s - setting hcr:0x%02x,lcr:0x%02x,quot:%d\n",
 291                 __func__, hcr, lcr, quot);
 292
 293         /* handshake control */
 294         if (priv->hcr != hcr) {
 295                 priv->hcr = hcr;
 296                 ark3116_write_reg(serial, 0x8, hcr);
 297         }
 298
 299         /* baudrate */
 300         if (priv->quot != quot) {
 301                 priv->quot = quot;
 302                 priv->lcr = lcr; /* need to write lcr anyway */
 303
 304                 /* disable DMA since transmit/receive is
 305                  * shadowed by UART_DLL
 306                  */
 307                 ark3116_write_reg(serial, UART_FCR, 0);
 308
 309                 ark3116_write_reg(serial, UART_LCR,
 310                                   lcr|UART_LCR_DLAB);
 311                 ark3116_write_reg(serial, UART_DLL, quot & 0xff);
 312                 ark3116_write_reg(serial, UART_DLM, (quot>>8) & 0xff);
 313
 314                 /* restore lcr */
 315                 ark3116_write_reg(serial, UART_LCR, lcr);
 316                 /* magic baudrate thingy: not sure what it does,
 317                  * but windows does this as well.
 318                  */
 319                 ark3116_write_reg(serial, 0xe, eval);
 320
 321                 /* enable DMA */
 322                 ark3116_write_reg(serial, UART_FCR, UART_FCR_DMA_SELECT);
 323         } else if (priv->lcr != lcr) {
 324                 priv->lcr = lcr;
 325                 ark3116_write_reg(serial, UART_LCR, lcr);
 326         }
 327
 328         mutex_unlock(&priv->hw_lock);
 329
 330         /* check for software flow control */
 331         if (I_IXOFF(tty) || I_IXON(tty)) {
 332                 dev_warn(&serial->dev->dev,
 333                          "%s: don't know how to do software flow control\n",
 334                          KBUILD_MODNAME);
 335         }
 336
 337         /* Don't rewrite B0 */
 338         if (tty_termios_baud_rate(termios))
 339                 tty_termios_encode_baud_rate(termios, bps, bps);
 340 }
 341
 342 static void ark3116_close(struct usb_serial_port *port)
 343 {
 344         struct usb_serial *serial = port->serial;
 345
 346         if (serial->dev) {
 347                 /* disable DMA */
 348                 ark3116_write_reg(serial, UART_FCR, 0);
 349
 350                 /* deactivate interrupts */
 351                 ark3116_write_reg(serial, UART_IER, 0);
 352
 353                 usb_serial_generic_close(port);
 354                 if (serial->num_interrupt_in)
 355                         usb_kill_urb(port->interrupt_in_urb);
 356         }
 357
 358 }
 359
 360 static int ark3116_open(struct tty_struct *tty, struct usb_serial_port *port)
 361 {
 362         struct ark3116_private *priv = usb_get_serial_port_data(port);
 363         struct usb_serial *serial = port->serial;
 364         unsigned char *buf;
 365         int result;
 366
 367         buf = kmalloc(1, GFP_KERNEL);
 368         if (buf == NULL)
 369                 return -ENOMEM;
 370
 371         result = usb_serial_generic_open(tty, port);
 372         if (result) {
 373                 dev_dbg(&port->dev,
 374                         "%s - usb_serial_generic_open failed: %d\n",
 375                         __func__, result);
 376                 goto err_out;
 377         }
 378
 379         /* remove any data still left: also clears error state */
 380         ark3116_read_reg(serial, UART_RX, buf);
 381
 382         /* read modem status */
 383         priv->msr = ark3116_read_reg(serial, UART_MSR, buf);
 384         /* read line status */
 385         priv->lsr = ark3116_read_reg(serial, UART_LSR, buf);
 386
 387         result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
 388         if (result) {
 389                 dev_err(&port->dev, "submit irq_in urb failed %d\n",
 390                         result);
 391                 ark3116_close(port);
 392                 goto err_out;
 393         }
 394
 395         /* activate interrupts */
 396         ark3116_write_reg(port->serial, UART_IER, UART_IER_MSI|UART_IER_RLSI);
 397
 398         /* enable DMA */
 399         ark3116_write_reg(port->serial, UART_FCR, UART_FCR_DMA_SELECT);
 400
 401         /* setup termios */
 402         if (tty)
 403                 ark3116_set_termios(tty, port, NULL);
 404
 405 err_out:
 406         kfree(buf);
 407         return result;
 408 }
 409
 410 static int ark3116_get_icount(struct tty_struct *tty,
 411                                         struct serial_icounter_struct *icount)
 412 {
 413         struct usb_serial_port *port = tty->driver_data;
 414         struct ark3116_private *priv = usb_get_serial_port_data(port);
 415         struct async_icount cnow = priv->icount;
 416         icount->cts = cnow.cts;
 417         icount->dsr = cnow.dsr;
 418         icount->rng = cnow.rng;
 419         icount->dcd = cnow.dcd;
 420         icount->rx = cnow.rx;
 421         icount->tx = cnow.tx;
 422         icount->frame = cnow.frame;
 423         icount->overrun = cnow.overrun;
 424         icount->parity = cnow.parity;
 425         icount->brk = cnow.brk;
 426         icount->buf_overrun = cnow.buf_overrun;
 427         return 0;
 428 }
 429
 430 static int ark3116_ioctl(struct tty_struct *tty,
 431                          unsigned int cmd, unsigned long arg)
 432 {
 433         struct usb_serial_port *port = tty->driver_data;
 434         struct ark3116_private *priv = usb_get_serial_port_data(port);
 435         struct serial_struct serstruct;
 436         void __user *user_arg = (void __user *)arg;
 437
 438         switch (cmd) {
 439         case TIOCGSERIAL:
 440                 /* XXX: Some of these values are probably wrong. */
 441                 memset(&serstruct, 0, sizeof(serstruct));
 442                 serstruct.type = PORT_16654;
 443                 serstruct.line = port->serial->minor;
 444                 serstruct.port = port->number;
 445                 serstruct.custom_divisor = 0;
 446                 serstruct.baud_base = 460800;
 447
 448                 if (copy_to_user(user_arg, &serstruct, sizeof(serstruct)))
 449                         return -EFAULT;
 450
 451                 return 0;
 452         case TIOCSSERIAL:
 453                 if (copy_from_user(&serstruct, user_arg, sizeof(serstruct)))
 454                         return -EFAULT;
 455                 return 0;
 456         case TIOCMIWAIT:
 457                 for (;;) {
 458                         struct async_icount prev = priv->icount;
 459                         interruptible_sleep_on(&priv->delta_msr_wait);
 460                         /* see if a signal did it */
 461                         if (signal_pending(current))
 462                                 return -ERESTARTSYS;
 463                         if ((prev.rng == priv->icount.rng) &&
 464                             (prev.dsr == priv->icount.dsr) &&
 465                             (prev.dcd == priv->icount.dcd) &&
 466                             (prev.cts == priv->icount.cts))
 467                                 return -EIO;
 468                         if ((arg & TIOCM_RNG &&
 469                              (prev.rng != priv->icount.rng)) ||
 470                             (arg & TIOCM_DSR &&
 471                              (prev.dsr != priv->icount.dsr)) ||
 472                             (arg & TIOCM_CD  &&
 473                              (prev.dcd != priv->icount.dcd)) ||
 474                             (arg & TIOCM_CTS &&
 475                              (prev.cts != priv->icount.cts)))
 476                                 return 0;
 477                 }
 478                 break;
 479         }
 480
 481         return -ENOIOCTLCMD;
 482 }
 483
 484 static int ark3116_tiocmget(struct tty_struct *tty)
 485 {
 486         struct usb_serial_port *port = tty->driver_data;
 487         struct ark3116_private *priv = usb_get_serial_port_data(port);
 488         __u32 status;
 489         __u32 ctrl;
 490         unsigned long flags;
 491
 492         mutex_lock(&priv->hw_lock);
 493         ctrl = priv->mcr;
 494         mutex_unlock(&priv->hw_lock);
 495
 496         spin_lock_irqsave(&priv->status_lock, flags);
 497         status = priv->msr;
 498         spin_unlock_irqrestore(&priv->status_lock, flags);
 499
 500         return  (status & UART_MSR_DSR  ? TIOCM_DSR  : 0) |
 501                 (status & UART_MSR_CTS  ? TIOCM_CTS  : 0) |
 502                 (status & UART_MSR_RI   ? TIOCM_RI   : 0) |
 503                 (status & UART_MSR_DCD  ? TIOCM_CD   : 0) |
 504                 (ctrl   & UART_MCR_DTR  ? TIOCM_DTR  : 0) |
 505                 (ctrl   & UART_MCR_RTS  ? TIOCM_RTS  : 0) |
 506                 (ctrl   & UART_MCR_OUT1 ? TIOCM_OUT1 : 0) |
 507                 (ctrl   & UART_MCR_OUT2 ? TIOCM_OUT2 : 0);
 508 }
 509
 510 static int ark3116_tiocmset(struct tty_struct *tty,
 511                         unsigned set, unsigned clr)
 512 {
 513         struct usb_serial_port *port = tty->driver_data;
 514         struct ark3116_private *priv = usb_get_serial_port_data(port);
 515
 516         /* we need to take the mutex here, to make sure that the value
 517          * in priv->mcr is actually the one that is in the hardware
 518          */
 519
 520         mutex_lock(&priv->hw_lock);
 521
 522         if (set & TIOCM_RTS)
 523                 priv->mcr |= UART_MCR_RTS;
 524         if (set & TIOCM_DTR)
 525                 priv->mcr |= UART_MCR_DTR;
 526         if (set & TIOCM_OUT1)
 527                 priv->mcr |= UART_MCR_OUT1;
 528         if (set & TIOCM_OUT2)
 529                 priv->mcr |= UART_MCR_OUT2;
 530         if (clr & TIOCM_RTS)
 531                 priv->mcr &= ~UART_MCR_RTS;
 532         if (clr & TIOCM_DTR)
 533                 priv->mcr &= ~UART_MCR_DTR;
 534         if (clr & TIOCM_OUT1)
 535                 priv->mcr &= ~UART_MCR_OUT1;
 536         if (clr & TIOCM_OUT2)
 537                 priv->mcr &= ~UART_MCR_OUT2;
 538
 539         ark3116_write_reg(port->serial, UART_MCR, priv->mcr);
 540
 541         mutex_unlock(&priv->hw_lock);
 542
 543         return 0;
 544 }
 545
 546 static void ark3116_break_ctl(struct tty_struct *tty, int break_state)
 547 {
 548         struct usb_serial_port *port = tty->driver_data;
 549         struct ark3116_private *priv = usb_get_serial_port_data(port);
 550
 551         /* LCR is also used for other things: protect access */
 552         mutex_lock(&priv->hw_lock);
 553
 554         if (break_state)
 555                 priv->lcr |= UART_LCR_SBC;
 556         else
 557                 priv->lcr &= ~UART_LCR_SBC;
 558
 559         ark3116_write_reg(port->serial, UART_LCR, priv->lcr);
 560
 561         mutex_unlock(&priv->hw_lock);
 562 }
 563
 564 static void ark3116_update_msr(struct usb_serial_port *port, __u8 msr)
 565 {
 566         struct ark3116_private *priv = usb_get_serial_port_data(port);
 567         unsigned long flags;
 568
 569         spin_lock_irqsave(&priv->status_lock, flags);
 570         priv->msr = msr;
 571         spin_unlock_irqrestore(&priv->status_lock, flags);
 572
 573         if (msr & UART_MSR_ANY_DELTA) {
 574                 /* update input line counters */
 575                 if (msr & UART_MSR_DCTS)
 576                         priv->icount.cts++;
 577                 if (msr & UART_MSR_DDSR)
 578                         priv->icount.dsr++;
 579                 if (msr & UART_MSR_DDCD)
 580                         priv->icount.dcd++;
 581                 if (msr & UART_MSR_TERI)
 582                         priv->icount.rng++;
 583                 wake_up_interruptible(&priv->delta_msr_wait);
 584         }
 585 }
 586
 587 static void ark3116_update_lsr(struct usb_serial_port *port, __u8 lsr)
 588 {
 589         struct ark3116_private *priv = usb_get_serial_port_data(port);
 590         unsigned long flags;
 591
 592         spin_lock_irqsave(&priv->status_lock, flags);
 593         /* combine bits */
 594         priv->lsr |= lsr;
 595         spin_unlock_irqrestore(&priv->status_lock, flags);
 596
 597         if (lsr&UART_LSR_BRK_ERROR_BITS) {
 598                 if (lsr & UART_LSR_BI)
 599                         priv->icount.brk++;
 600                 if (lsr & UART_LSR_FE)
 601                         priv->icount.frame++;
 602                 if (lsr & UART_LSR_PE)
 603                         priv->icount.parity++;
 604                 if (lsr & UART_LSR_OE)
 605                         priv->icount.overrun++;
 606         }
 607 }
 608
 609 static void ark3116_read_int_callback(struct urb *urb)
 610 {
 611         struct usb_serial_port *port = urb->context;
 612         int status = urb->status;
 613         const __u8 *data = urb->transfer_buffer;
 614         int result;
 615
 616         switch (status) {
 617         case -ECONNRESET:
 618         case -ENOENT:
 619         case -ESHUTDOWN:
 620                 /* this urb is terminated, clean up */
 621                 dev_dbg(&port->dev, "%s - urb shutting down with status: %d\n",
 622                         __func__, status);
 623                 return;
 624         default:
 625                 dev_dbg(&port->dev, "%s - nonzero urb status received: %d\n",
 626                         __func__, status);
 627                 break;
 628         case 0: /* success */
 629                 /* discovered this by trail and error... */
 630                 if ((urb->actual_length == 4) && (data[0] == 0xe8)) {
 631                         const __u8 id = data[1]&UART_IIR_ID;
 632                         dev_dbg(&port->dev, "%s: iir=%02x\n", __func__, data[1]);
 633                         if (id == UART_IIR_MSI) {
 634                                 dev_dbg(&port->dev, "%s: msr=%02x\n",
 635                                         __func__, data[3]);
 636                                 ark3116_update_msr(port, data[3]);
 637                                 break;
 638                         } else if (id == UART_IIR_RLSI) {
 639                                 dev_dbg(&port->dev, "%s: lsr=%02x\n",
 640                                         __func__, data[2]);
 641                                 ark3116_update_lsr(port, data[2]);
 642                                 break;
 643                         }
 644                 }
 645                 /*
 646                  * Not sure what this data meant...
 647                  */
 648                 usb_serial_debug_data(&port->dev, __func__,
 649                                       urb->actual_length,
 650                                       urb->transfer_buffer);
 651                 break;
 652         }
 653
 654         result = usb_submit_urb(urb, GFP_ATOMIC);
 655         if (result)
 656                 dev_err(&urb->dev->dev,
 657                         "%s - Error %d submitting interrupt urb\n",
 658                         __func__, result);
 659 }
 660
 661
 662 /* Data comes in via the bulk (data) URB, erors/interrupts via the int URB.
 663  * This means that we cannot be sure which data byte has an associated error
 664  * condition, so we report an error for all data in the next bulk read.
 665  *
 666  * Actually, there might even be a window between the bulk data leaving the
 667  * ark and reading/resetting the lsr in the read_bulk_callback where an
 668  * interrupt for the next data block could come in.
 669  * Without somekind of ordering on the ark, we would have to report the
 670  * error for the next block of data as well...
 671  * For now, let's pretend this can't happen.
 672  */
 673 static void ark3116_process_read_urb(struct urb *urb)
 674 {
 675         struct usb_serial_port *port = urb->context;
 676         struct ark3116_private *priv = usb_get_serial_port_data(port);
 677         unsigned char *data = urb->transfer_buffer;
 678         char tty_flag = TTY_NORMAL;
 679         unsigned long flags;
 680         __u32 lsr;
 681
 682         /* update line status */
 683         spin_lock_irqsave(&priv->status_lock, flags);
 684         lsr = priv->lsr;
 685         priv->lsr &= ~UART_LSR_BRK_ERROR_BITS;
 686         spin_unlock_irqrestore(&priv->status_lock, flags);
 687
 688         if (!urb->actual_length)
 689                 return;
 690
 691         if (lsr & UART_LSR_BRK_ERROR_BITS) {
 692                 if (lsr & UART_LSR_BI)
 693                         tty_flag = TTY_BREAK;
 694                 else if (lsr & UART_LSR_PE)
 695                         tty_flag = TTY_PARITY;
 696                 else if (lsr & UART_LSR_FE)
 697                         tty_flag = TTY_FRAME;
 698
 699                 /* overrun is special, not associated with a char */
 700                 if (lsr & UART_LSR_OE)
 701                         tty_insert_flip_char(&port->port, 0, TTY_OVERRUN);
 702         }
 703         tty_insert_flip_string_fixed_flag(&port->port, data, tty_flag,
 704                                                         urb->actual_length);
 705         tty_flip_buffer_push(&port->port);
 706 }
 707
 708 static struct usb_serial_driver ark3116_device = {
 709         .driver = {
 710                 .owner =        THIS_MODULE,
 711                 .name =         "ark3116",
 712         },
 713         .id_table =             id_table,
 714         .num_ports =            1,
 715         .attach =               ark3116_attach,
 716         .port_probe =           ark3116_port_probe,
 717         .port_remove =          ark3116_port_remove,
 718         .set_termios =          ark3116_set_termios,
 719         .init_termios =         ark3116_init_termios,
 720         .ioctl =                ark3116_ioctl,
 721         .tiocmget =             ark3116_tiocmget,
 722         .tiocmset =             ark3116_tiocmset,
 723         .get_icount =           ark3116_get_icount,
 724         .open =                 ark3116_open,
 725         .close =                ark3116_close,
 726         .break_ctl =            ark3116_break_ctl,
 727         .read_int_callback =    ark3116_read_int_callback,
 728         .process_read_urb =     ark3116_process_read_urb,
 729 };
 730
 731 static struct usb_serial_driver * const serial_drivers[] = {
 732         &ark3116_device, NULL
 733 };
 734
 735 module_usb_serial_driver(serial_drivers, id_table);
 736
 737 MODULE_LICENSE("GPL");
 738
 739 MODULE_AUTHOR(DRIVER_AUTHOR);
 740 MODULE_DESCRIPTION(DRIVER_DESC);
 741
 742 /*
 743  * The following describes what I learned from studying the old
 744  * ark3116.c driver, disassembling the windows driver, and some lucky
 745  * guesses. Since I do not have any datasheet or other
 746  * documentation, inaccuracies are almost guaranteed.
 747  *
 748  * Some specs for the ARK3116 can be found here:
 749  * http://web.archive.org/web/20060318000438/
 750  *   www.arkmicro.com/en/products/view.php?id=10
 751  * On that page, 2 GPIO pins are mentioned: I assume these are the
 752  * OUT1 and OUT2 pins of the UART, so I added support for those
 753  * through the MCR. Since the pins are not available on my hardware,
 754  * I could not verify this.
 755  * Also, it states there is "on-chip hardware flow control". I have
 756  * discovered how to enable that. Unfortunately, I do not know how to
 757  * enable XON/XOFF (software) flow control, which would need support
 758  * from the chip as well to work. Because of the wording on the web
 759  * page there is a real possibility the chip simply does not support
 760  * software flow control.
 761  *
 762  * I got my ark3116 as part of a mobile phone adapter cable. On the
 763  * PCB, the following numbered contacts are present:
 764  *
 765  *  1:- +5V
 766  *  2:o DTR
 767  *  3:i RX
 768  *  4:i DCD
 769  *  5:o RTS
 770  *  6:o TX
 771  *  7:i RI
 772  *  8:i DSR
 773  * 10:- 0V
 774  * 11:i CTS
 775  *
 776  * On my chip, all signals seem to be 3.3V, but 5V tolerant. But that
 777  * may be different for the one you have ;-).
 778  *
 779  * The windows driver limits the registers to 0-F, so I assume there
 780  * are actually 16 present on the device.
 781  *
 782  * On an UART interrupt, 4 bytes of data come in on the interrupt
 783  * endpoint. The bytes are 0xe8 IIR LSR MSR.
 784  *
 785  * The baudrate seems to be generated from the 12MHz crystal, using
 786  * 4-times subsampling. So quot=12e6/(4*baud). Also see description
 787  * of register E.
 788  *
 789  * Registers 0-7:
 790  * These seem to be the same as for a regular 16450. The FCR is set
 791  * to UART_FCR_DMA_SELECT (0x8), I guess to enable transfers between
 792  * the UART and the USB bridge/DMA engine.
 793  *
 794  * Register 8:
 795  * By trial and error, I found out that bit 0 enables hardware CTS,
 796  * stopping TX when CTS is +5V. Bit 1 does the same for RTS, making
 797  * RTS +5V when the 3116 cannot transfer the data to the USB bus
 798  * (verified by disabling the reading URB). Note that as far as I can
 799  * tell, the windows driver does NOT use this, so there might be some
 800  * hardware bug or something.
 801  *
 802  * According to a patch provided here
 803  * (http://lkml.org/lkml/2009/7/26/56), the ARK3116 can also be used
 804  * as an IrDA dongle. Since I do not have such a thing, I could not
 805  * investigate that aspect. However, I can speculate ;-).
 806  *
 807  * - IrDA encodes data differently than RS232. Most likely, one of
 808  *   the bits in registers 9..E enables the IR ENDEC (encoder/decoder).
 809  * - Depending on the IR transceiver, the input and output need to be
 810  *   inverted, so there are probably bits for that as well.
 811  * - IrDA is half-duplex, so there should be a bit for selecting that.
 812  *
 813  * This still leaves at least two registers unaccounted for. Perhaps
 814  * The chip can do XON/XOFF or CRC in HW?
 815  *
 816  * Register 9:
 817  * Set to 0x00 for IrDA, when the baudrate is initialised.
 818  *
 819  * Register A:
 820  * Set to 0x01 for IrDA, at init.
 821  *
 822  * Register B:
 823  * Set to 0x01 for IrDA, 0x00 for RS232, at init.
 824  *
 825  * Register C:
 826  * Set to 00 for IrDA, at init.
 827  *
 828  * Register D:
 829  * Set to 0x41 for IrDA, at init.
 830  *
 831  * Register E:
 832  * Somekind of baudrate override. The windows driver seems to set
 833  * this to 0x00 for normal baudrates, 0x01 for 460800, 0x02 for 921600.
 834  * Since 460800 and 921600 cannot be obtained by dividing 3MHz by an integer,
 835  * it could be somekind of subdivisor thingy.
 836  * However,it does not seem to do anything: selecting 921600 (divisor 3,
 837  * reg E=2), still gets 1 MHz. I also checked if registers 9, C or F would
 838  * work, but they don't.
 839  *
 840  * Register F: unknown
 841  */