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 static bool debug;
  41 /*
  42  * Version information
  43  */
  44
  45 #define DRIVER_VERSION "v0.7"
  46 #define DRIVER_AUTHOR "Bart Hartgers <bart.hartgers+ark3116@gmail.com>"
  47 #define DRIVER_DESC "USB ARK3116 serial/IrDA driver"
  48 #define DRIVER_DEV_DESC "ARK3116 RS232/IrDA"
  49 #define DRIVER_NAME "ark3116"
  50
  51 /* usb timeout of 1 second */
  52 #define ARK_TIMEOUT (1*HZ)
  53
  54 static const struct usb_device_id id_table[] = {
  55         { USB_DEVICE(0x6547, 0x0232) },
  56         { USB_DEVICE(0x18ec, 0x3118) },         /* USB to IrDA adapter */
  57         { },
  58 };
  59 MODULE_DEVICE_TABLE(usb, id_table);
  60
  61 static int is_irda(struct usb_serial *serial)
  62 {
  63         struct usb_device *dev = serial->dev;
  64         if (le16_to_cpu(dev->descriptor.idVendor) == 0x18ec &&
  65                         le16_to_cpu(dev->descriptor.idProduct) == 0x3118)
  66                 return 1;
  67         return 0;
  68 }
  69
  70 struct ark3116_private {
  71         wait_queue_head_t       delta_msr_wait;
  72         struct async_icount     icount;
  73         int                     irda;   /* 1 for irda device */
  74
  75         /* protects hw register updates */
  76         struct mutex            hw_lock;
  77
  78         int                     quot;   /* baudrate divisor */
  79         __u32                   lcr;    /* line control register value */
  80         __u32                   hcr;    /* handshake control register (0x8)
  81                                          * value */
  82         __u32                   mcr;    /* modem contol register value */
  83
  84         /* protects the status values below */
  85         spinlock_t              status_lock;
  86         __u32                   msr;    /* modem status register value */
  87         __u32                   lsr;    /* line status register value */
  88 };
  89
  90 static int ark3116_write_reg(struct usb_serial *serial,
  91                              unsigned reg, __u8 val)
  92 {
  93         int result;
  94          /* 0xfe 0x40 are magic values taken from original driver */
  95         result = usb_control_msg(serial->dev,
  96                                  usb_sndctrlpipe(serial->dev, 0),
  97                                  0xfe, 0x40, val, reg,
  98                                  NULL, 0, ARK_TIMEOUT);
  99         return result;
 100 }
 101
 102 static int ark3116_read_reg(struct usb_serial *serial,
 103                             unsigned reg, unsigned char *buf)
 104 {
 105         int result;
 106         /* 0xfe 0xc0 are magic values taken from original driver */
 107         result = usb_control_msg(serial->dev,
 108                                  usb_rcvctrlpipe(serial->dev, 0),
 109                                  0xfe, 0xc0, 0, reg,
 110                                  buf, 1, ARK_TIMEOUT);
 111         if (result < 0)
 112                 return result;
 113         else
 114                 return buf[0];
 115 }
 116
 117 static inline int calc_divisor(int bps)
 118 {
 119         /* Original ark3116 made some exceptions in rounding here
 120          * because windows did the same. Assume that is not really
 121          * necessary.
 122          * Crystal is 12MHz, probably because of USB, but we divide by 4?
 123          */
 124         return (12000000 + 2*bps) / (4*bps);
 125 }
 126
 127 static int ark3116_attach(struct usb_serial *serial)
 128 {
 129         struct usb_serial_port *port = serial->port[0];
 130         struct ark3116_private *priv;
 131
 132         /* make sure we have our end-points */
 133         if ((serial->num_bulk_in == 0) ||
 134             (serial->num_bulk_out == 0) ||
 135             (serial->num_interrupt_in == 0)) {
 136                 dev_err(&serial->dev->dev,
 137                         "%s - missing endpoint - "
 138                         "bulk in: %d, bulk out: %d, int in %d\n",
 139                         KBUILD_MODNAME,
 140                         serial->num_bulk_in,
 141                         serial->num_bulk_out,
 142                         serial->num_interrupt_in);
 143                 return -EINVAL;
 144         }
 145
 146         priv = kzalloc(sizeof(struct ark3116_private),
 147                        GFP_KERNEL);
 148         if (!priv)
 149                 return -ENOMEM;
 150
 151         init_waitqueue_head(&priv->delta_msr_wait);
 152         mutex_init(&priv->hw_lock);
 153         spin_lock_init(&priv->status_lock);
 154
 155         priv->irda = is_irda(serial);
 156
 157         usb_set_serial_port_data(port, priv);
 158
 159         /* setup the hardware */
 160         ark3116_write_reg(serial, UART_IER, 0);
 161         /* disable DMA */
 162         ark3116_write_reg(serial, UART_FCR, 0);
 163         /* handshake control */
 164         priv->hcr = 0;
 165         ark3116_write_reg(serial, 0x8     , 0);
 166         /* modem control */
 167         priv->mcr = 0;
 168         ark3116_write_reg(serial, UART_MCR, 0);
 169
 170         if (!(priv->irda)) {
 171                 ark3116_write_reg(serial, 0xb , 0);
 172         } else {
 173                 ark3116_write_reg(serial, 0xb , 1);
 174                 ark3116_write_reg(serial, 0xc , 0);
 175                 ark3116_write_reg(serial, 0xd , 0x41);
 176                 ark3116_write_reg(serial, 0xa , 1);
 177         }
 178
 179         /* setup baudrate */
 180         ark3116_write_reg(serial, UART_LCR, UART_LCR_DLAB);
 181
 182         /* setup for 9600 8N1 */
 183         priv->quot = calc_divisor(9600);
 184         ark3116_write_reg(serial, UART_DLL, priv->quot & 0xff);
 185         ark3116_write_reg(serial, UART_DLM, (priv->quot>>8) & 0xff);
 186
 187         priv->lcr = UART_LCR_WLEN8;
 188         ark3116_write_reg(serial, UART_LCR, UART_LCR_WLEN8);
 189
 190         ark3116_write_reg(serial, 0xe, 0);
 191
 192         if (priv->irda)
 193                 ark3116_write_reg(serial, 0x9, 0);
 194
 195         dev_info(&serial->dev->dev,
 196                 "%s using %s mode\n",
 197                 KBUILD_MODNAME,
 198                 priv->irda ? "IrDA" : "RS232");
 199         return 0;
 200 }
 201
 202 static void ark3116_release(struct usb_serial *serial)
 203 {
 204         struct usb_serial_port *port = serial->port[0];
 205         struct ark3116_private *priv = usb_get_serial_port_data(port);
 206
 207         /* device is closed, so URBs and DMA should be down */
 208
 209         usb_set_serial_port_data(port, NULL);
 210
 211         mutex_destroy(&priv->hw_lock);
 212
 213         kfree(priv);
 214 }
 215
 216 static void ark3116_init_termios(struct tty_struct *tty)
 217 {
 218         struct ktermios *termios = tty->termios;
 219         *termios = tty_std_termios;
 220         termios->c_cflag = B9600 | CS8
 221                                       | CREAD | HUPCL | CLOCAL;
 222         termios->c_ispeed = 9600;
 223         termios->c_ospeed = 9600;
 224 }
 225
 226 static void ark3116_set_termios(struct tty_struct *tty,
 227                                 struct usb_serial_port *port,
 228                                 struct ktermios *old_termios)
 229 {
 230         struct usb_serial *serial = port->serial;
 231         struct ark3116_private *priv = usb_get_serial_port_data(port);
 232         struct ktermios *termios = tty->termios;
 233         unsigned int cflag = termios->c_cflag;
 234         int bps = tty_get_baud_rate(tty);
 235         int quot;
 236         __u8 lcr, hcr, eval;
 237
 238         /* set data bit count */
 239         switch (cflag & CSIZE) {
 240         case CS5:
 241                 lcr = UART_LCR_WLEN5;
 242                 break;
 243         case CS6:
 244                 lcr = UART_LCR_WLEN6;
 245                 break;
 246         case CS7:
 247                 lcr = UART_LCR_WLEN7;
 248                 break;
 249         default:
 250         case CS8:
 251                 lcr = UART_LCR_WLEN8;
 252                 break;
 253         }
 254         if (cflag & CSTOPB)
 255                 lcr |= UART_LCR_STOP;
 256         if (cflag & PARENB)
 257                 lcr |= UART_LCR_PARITY;
 258         if (!(cflag & PARODD))
 259                 lcr |= UART_LCR_EPAR;
 260 #ifdef CMSPAR
 261         if (cflag & CMSPAR)
 262                 lcr |= UART_LCR_SPAR;
 263 #endif
 264         /* handshake control */
 265         hcr = (cflag & CRTSCTS) ? 0x03 : 0x00;
 266
 267         /* calc baudrate */
 268         dbg("%s - setting bps to %d", __func__, bps);
 269         eval = 0;
 270         switch (bps) {
 271         case 0:
 272                 quot = calc_divisor(9600);
 273                 break;
 274         default:
 275                 if ((bps < 75) || (bps > 3000000))
 276                         bps = 9600;
 277                 quot = calc_divisor(bps);
 278                 break;
 279         case 460800:
 280                 eval = 1;
 281                 quot = calc_divisor(bps);
 282                 break;
 283         case 921600:
 284                 eval = 2;
 285                 quot = calc_divisor(bps);
 286                 break;
 287         }
 288
 289         /* Update state: synchronize */
 290         mutex_lock(&priv->hw_lock);
 291
 292         /* keep old LCR_SBC bit */
 293         lcr |= (priv->lcr & UART_LCR_SBC);
 294
 295         dbg("%s - setting hcr:0x%02x,lcr:0x%02x,quot:%d",
 296             __func__, hcr, lcr, quot);
 297
 298         /* handshake control */
 299         if (priv->hcr != hcr) {
 300                 priv->hcr = hcr;
 301                 ark3116_write_reg(serial, 0x8, hcr);
 302         }
 303
 304         /* baudrate */
 305         if (priv->quot != quot) {
 306                 priv->quot = quot;
 307                 priv->lcr = lcr; /* need to write lcr anyway */
 308
 309                 /* disable DMA since transmit/receive is
 310                  * shadowed by UART_DLL
 311                  */
 312                 ark3116_write_reg(serial, UART_FCR, 0);
 313
 314                 ark3116_write_reg(serial, UART_LCR,
 315                                   lcr|UART_LCR_DLAB);
 316                 ark3116_write_reg(serial, UART_DLL, quot & 0xff);
 317                 ark3116_write_reg(serial, UART_DLM, (quot>>8) & 0xff);
 318
 319                 /* restore lcr */
 320                 ark3116_write_reg(serial, UART_LCR, lcr);
 321                 /* magic baudrate thingy: not sure what it does,
 322                  * but windows does this as well.
 323                  */
 324                 ark3116_write_reg(serial, 0xe, eval);
 325
 326                 /* enable DMA */
 327                 ark3116_write_reg(serial, UART_FCR, UART_FCR_DMA_SELECT);
 328         } else if (priv->lcr != lcr) {
 329                 priv->lcr = lcr;
 330                 ark3116_write_reg(serial, UART_LCR, lcr);
 331         }
 332
 333         mutex_unlock(&priv->hw_lock);
 334
 335         /* check for software flow control */
 336         if (I_IXOFF(tty) || I_IXON(tty)) {
 337                 dev_warn(&serial->dev->dev,
 338                          "%s: don't know how to do software flow control\n",
 339                          KBUILD_MODNAME);
 340         }
 341
 342         /* Don't rewrite B0 */
 343         if (tty_termios_baud_rate(termios))
 344                 tty_termios_encode_baud_rate(termios, bps, bps);
 345 }
 346
 347 static void ark3116_close(struct usb_serial_port *port)
 348 {
 349         struct usb_serial *serial = port->serial;
 350
 351         if (serial->dev) {
 352                 /* disable DMA */
 353                 ark3116_write_reg(serial, UART_FCR, 0);
 354
 355                 /* deactivate interrupts */
 356                 ark3116_write_reg(serial, UART_IER, 0);
 357
 358                 usb_serial_generic_close(port);
 359                 if (serial->num_interrupt_in)
 360                         usb_kill_urb(port->interrupt_in_urb);
 361         }
 362
 363 }
 364
 365 static int ark3116_open(struct tty_struct *tty, struct usb_serial_port *port)
 366 {
 367         struct ark3116_private *priv = usb_get_serial_port_data(port);
 368         struct usb_serial *serial = port->serial;
 369         unsigned char *buf;
 370         int result;
 371
 372         buf = kmalloc(1, GFP_KERNEL);
 373         if (buf == NULL)
 374                 return -ENOMEM;
 375
 376         result = usb_serial_generic_open(tty, port);
 377         if (result) {
 378                 dbg("%s - usb_serial_generic_open failed: %d",
 379                     __func__, result);
 380                 goto err_out;
 381         }
 382
 383         /* remove any data still left: also clears error state */
 384         ark3116_read_reg(serial, UART_RX, buf);
 385
 386         /* read modem status */
 387         priv->msr = ark3116_read_reg(serial, UART_MSR, buf);
 388         /* read line status */
 389         priv->lsr = ark3116_read_reg(serial, UART_LSR, buf);
 390
 391         result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
 392         if (result) {
 393                 dev_err(&port->dev, "submit irq_in urb failed %d\n",
 394                         result);
 395                 ark3116_close(port);
 396                 goto err_out;
 397         }
 398
 399         /* activate interrupts */
 400         ark3116_write_reg(port->serial, UART_IER, UART_IER_MSI|UART_IER_RLSI);
 401
 402         /* enable DMA */
 403         ark3116_write_reg(port->serial, UART_FCR, UART_FCR_DMA_SELECT);
 404
 405         /* setup termios */
 406         if (tty)
 407                 ark3116_set_termios(tty, port, NULL);
 408
 409 err_out:
 410         kfree(buf);
 411         return result;
 412 }
 413
 414 static int ark3116_get_icount(struct tty_struct *tty,
 415                                         struct serial_icounter_struct *icount)
 416 {
 417         struct usb_serial_port *port = tty->driver_data;
 418         struct ark3116_private *priv = usb_get_serial_port_data(port);
 419         struct async_icount cnow = priv->icount;
 420         icount->cts = cnow.cts;
 421         icount->dsr = cnow.dsr;
 422         icount->rng = cnow.rng;
 423         icount->dcd = cnow.dcd;
 424         icount->rx = cnow.rx;
 425         icount->tx = cnow.tx;
 426         icount->frame = cnow.frame;
 427         icount->overrun = cnow.overrun;
 428         icount->parity = cnow.parity;
 429         icount->brk = cnow.brk;
 430         icount->buf_overrun = cnow.buf_overrun;
 431         return 0;
 432 }
 433
 434 static int ark3116_ioctl(struct tty_struct *tty,
 435                          unsigned int cmd, unsigned long arg)
 436 {
 437         struct usb_serial_port *port = tty->driver_data;
 438         struct ark3116_private *priv = usb_get_serial_port_data(port);
 439         struct serial_struct serstruct;
 440         void __user *user_arg = (void __user *)arg;
 441
 442         switch (cmd) {
 443         case TIOCGSERIAL:
 444                 /* XXX: Some of these values are probably wrong. */
 445                 memset(&serstruct, 0, sizeof(serstruct));
 446                 serstruct.type = PORT_16654;
 447                 serstruct.line = port->serial->minor;
 448                 serstruct.port = port->number;
 449                 serstruct.custom_divisor = 0;
 450                 serstruct.baud_base = 460800;
 451
 452                 if (copy_to_user(user_arg, &serstruct, sizeof(serstruct)))
 453                         return -EFAULT;
 454
 455                 return 0;
 456         case TIOCSSERIAL:
 457                 if (copy_from_user(&serstruct, user_arg, sizeof(serstruct)))
 458                         return -EFAULT;
 459                 return 0;
 460         case TIOCMIWAIT:
 461                 for (;;) {
 462                         struct async_icount prev = priv->icount;
 463                         interruptible_sleep_on(&priv->delta_msr_wait);
 464                         /* see if a signal did it */
 465                         if (signal_pending(current))
 466                                 return -ERESTARTSYS;
 467                         if ((prev.rng == priv->icount.rng) &&
 468                             (prev.dsr == priv->icount.dsr) &&
 469                             (prev.dcd == priv->icount.dcd) &&
 470                             (prev.cts == priv->icount.cts))
 471                                 return -EIO;
 472                         if ((arg & TIOCM_RNG &&
 473                              (prev.rng != priv->icount.rng)) ||
 474                             (arg & TIOCM_DSR &&
 475                              (prev.dsr != priv->icount.dsr)) ||
 476                             (arg & TIOCM_CD  &&
 477                              (prev.dcd != priv->icount.dcd)) ||
 478                             (arg & TIOCM_CTS &&
 479                              (prev.cts != priv->icount.cts)))
 480                                 return 0;
 481                 }
 482                 break;
 483         }
 484
 485         return -ENOIOCTLCMD;
 486 }
 487
 488 static int ark3116_tiocmget(struct tty_struct *tty)
 489 {
 490         struct usb_serial_port *port = tty->driver_data;
 491         struct ark3116_private *priv = usb_get_serial_port_data(port);
 492         __u32 status;
 493         __u32 ctrl;
 494         unsigned long flags;
 495
 496         mutex_lock(&priv->hw_lock);
 497         ctrl = priv->mcr;
 498         mutex_unlock(&priv->hw_lock);
 499
 500         spin_lock_irqsave(&priv->status_lock, flags);
 501         status = priv->msr;
 502         spin_unlock_irqrestore(&priv->status_lock, flags);
 503
 504         return  (status & UART_MSR_DSR  ? TIOCM_DSR  : 0) |
 505                 (status & UART_MSR_CTS  ? TIOCM_CTS  : 0) |
 506                 (status & UART_MSR_RI   ? TIOCM_RI   : 0) |
 507                 (status & UART_MSR_DCD  ? TIOCM_CD   : 0) |
 508                 (ctrl   & UART_MCR_DTR  ? TIOCM_DTR  : 0) |
 509                 (ctrl   & UART_MCR_RTS  ? TIOCM_RTS  : 0) |
 510                 (ctrl   & UART_MCR_OUT1 ? TIOCM_OUT1 : 0) |
 511                 (ctrl   & UART_MCR_OUT2 ? TIOCM_OUT2 : 0);
 512 }
 513
 514 static int ark3116_tiocmset(struct tty_struct *tty,
 515                         unsigned set, unsigned clr)
 516 {
 517         struct usb_serial_port *port = tty->driver_data;
 518         struct ark3116_private *priv = usb_get_serial_port_data(port);
 519
 520         /* we need to take the mutex here, to make sure that the value
 521          * in priv->mcr is actually the one that is in the hardware
 522          */
 523
 524         mutex_lock(&priv->hw_lock);
 525
 526         if (set & TIOCM_RTS)
 527                 priv->mcr |= UART_MCR_RTS;
 528         if (set & TIOCM_DTR)
 529                 priv->mcr |= UART_MCR_DTR;
 530         if (set & TIOCM_OUT1)
 531                 priv->mcr |= UART_MCR_OUT1;
 532         if (set & TIOCM_OUT2)
 533                 priv->mcr |= UART_MCR_OUT2;
 534         if (clr & TIOCM_RTS)
 535                 priv->mcr &= ~UART_MCR_RTS;
 536         if (clr & TIOCM_DTR)
 537                 priv->mcr &= ~UART_MCR_DTR;
 538         if (clr & TIOCM_OUT1)
 539                 priv->mcr &= ~UART_MCR_OUT1;
 540         if (clr & TIOCM_OUT2)
 541                 priv->mcr &= ~UART_MCR_OUT2;
 542
 543         ark3116_write_reg(port->serial, UART_MCR, priv->mcr);
 544
 545         mutex_unlock(&priv->hw_lock);
 546
 547         return 0;
 548 }
 549
 550 static void ark3116_break_ctl(struct tty_struct *tty, int break_state)
 551 {
 552         struct usb_serial_port *port = tty->driver_data;
 553         struct ark3116_private *priv = usb_get_serial_port_data(port);
 554
 555         /* LCR is also used for other things: protect access */
 556         mutex_lock(&priv->hw_lock);
 557
 558         if (break_state)
 559                 priv->lcr |= UART_LCR_SBC;
 560         else
 561                 priv->lcr &= ~UART_LCR_SBC;
 562
 563         ark3116_write_reg(port->serial, UART_LCR, priv->lcr);
 564
 565         mutex_unlock(&priv->hw_lock);
 566 }
 567
 568 static void ark3116_update_msr(struct usb_serial_port *port, __u8 msr)
 569 {
 570         struct ark3116_private *priv = usb_get_serial_port_data(port);
 571         unsigned long flags;
 572
 573         spin_lock_irqsave(&priv->status_lock, flags);
 574         priv->msr = msr;
 575         spin_unlock_irqrestore(&priv->status_lock, flags);
 576
 577         if (msr & UART_MSR_ANY_DELTA) {
 578                 /* update input line counters */
 579                 if (msr & UART_MSR_DCTS)
 580                         priv->icount.cts++;
 581                 if (msr & UART_MSR_DDSR)
 582                         priv->icount.dsr++;
 583                 if (msr & UART_MSR_DDCD)
 584                         priv->icount.dcd++;
 585                 if (msr & UART_MSR_TERI)
 586                         priv->icount.rng++;
 587                 wake_up_interruptible(&priv->delta_msr_wait);
 588         }
 589 }
 590
 591 static void ark3116_update_lsr(struct usb_serial_port *port, __u8 lsr)
 592 {
 593         struct ark3116_private *priv = usb_get_serial_port_data(port);
 594         unsigned long flags;
 595
 596         spin_lock_irqsave(&priv->status_lock, flags);
 597         /* combine bits */
 598         priv->lsr |= lsr;
 599         spin_unlock_irqrestore(&priv->status_lock, flags);
 600
 601         if (lsr&UART_LSR_BRK_ERROR_BITS) {
 602                 if (lsr & UART_LSR_BI)
 603                         priv->icount.brk++;
 604                 if (lsr & UART_LSR_FE)
 605                         priv->icount.frame++;
 606                 if (lsr & UART_LSR_PE)
 607                         priv->icount.parity++;
 608                 if (lsr & UART_LSR_OE)
 609                         priv->icount.overrun++;
 610         }
 611 }
 612
 613 static void ark3116_read_int_callback(struct urb *urb)
 614 {
 615         struct usb_serial_port *port = urb->context;
 616         int status = urb->status;
 617         const __u8 *data = urb->transfer_buffer;
 618         int result;
 619
 620         switch (status) {
 621         case -ECONNRESET:
 622         case -ENOENT:
 623         case -ESHUTDOWN:
 624                 /* this urb is terminated, clean up */
 625                 dbg("%s - urb shutting down with status: %d",
 626                     __func__, status);
 627                 return;
 628         default:
 629                 dbg("%s - nonzero urb status received: %d",
 630                     __func__, status);
 631                 break;
 632         case 0: /* success */
 633                 /* discovered this by trail and error... */
 634                 if ((urb->actual_length == 4) && (data[0] == 0xe8)) {
 635                         const __u8 id = data[1]&UART_IIR_ID;
 636                         dbg("%s: iir=%02x", __func__, data[1]);
 637                         if (id == UART_IIR_MSI) {
 638                                 dbg("%s: msr=%02x", __func__, data[3]);
 639                                 ark3116_update_msr(port, data[3]);
 640                                 break;
 641                         } else if (id == UART_IIR_RLSI) {
 642                                 dbg("%s: lsr=%02x", __func__, data[2]);
 643                                 ark3116_update_lsr(port, data[2]);
 644                                 break;
 645                         }
 646                 }
 647                 /*
 648                  * Not sure what this data meant...
 649                  */
 650                 usb_serial_debug_data(debug, &port->dev,
 651                                       __func__,
 652                                       urb->actual_length,
 653                                       urb->transfer_buffer);
 654                 break;
 655         }
 656
 657         result = usb_submit_urb(urb, GFP_ATOMIC);
 658         if (result)
 659                 dev_err(&urb->dev->dev,
 660                         "%s - Error %d submitting interrupt urb\n",
 661                         __func__, result);
 662 }
 663
 664
 665 /* Data comes in via the bulk (data) URB, erors/interrupts via the int URB.
 666  * This means that we cannot be sure which data byte has an associated error
 667  * condition, so we report an error for all data in the next bulk read.
 668  *
 669  * Actually, there might even be a window between the bulk data leaving the
 670  * ark and reading/resetting the lsr in the read_bulk_callback where an
 671  * interrupt for the next data block could come in.
 672  * Without somekind of ordering on the ark, we would have to report the
 673  * error for the next block of data as well...
 674  * For now, let's pretend this can't happen.
 675  */
 676 static void ark3116_process_read_urb(struct urb *urb)
 677 {
 678         struct usb_serial_port *port = urb->context;
 679         struct ark3116_private *priv = usb_get_serial_port_data(port);
 680         struct tty_struct *tty;
 681         unsigned char *data = urb->transfer_buffer;
 682         char tty_flag = TTY_NORMAL;
 683         unsigned long flags;
 684         __u32 lsr;
 685
 686         /* update line status */
 687         spin_lock_irqsave(&priv->status_lock, flags);
 688         lsr = priv->lsr;
 689         priv->lsr &= ~UART_LSR_BRK_ERROR_BITS;
 690         spin_unlock_irqrestore(&priv->status_lock, flags);
 691
 692         if (!urb->actual_length)
 693                 return;
 694
 695         tty = tty_port_tty_get(&port->port);
 696         if (!tty)
 697                 return;
 698
 699         if (lsr & UART_LSR_BRK_ERROR_BITS) {
 700                 if (lsr & UART_LSR_BI)
 701                         tty_flag = TTY_BREAK;
 702                 else if (lsr & UART_LSR_PE)
 703                         tty_flag = TTY_PARITY;
 704                 else if (lsr & UART_LSR_FE)
 705                         tty_flag = TTY_FRAME;
 706
 707                 /* overrun is special, not associated with a char */
 708                 if (lsr & UART_LSR_OE)
 709                         tty_insert_flip_char(tty, 0, TTY_OVERRUN);
 710         }
 711         tty_insert_flip_string_fixed_flag(tty, data, tty_flag,
 712                                                         urb->actual_length);
 713         tty_flip_buffer_push(tty);
 714         tty_kref_put(tty);
 715 }
 716
 717 static struct usb_driver ark3116_driver = {
 718         .name =         "ark3116",
 719         .probe =        usb_serial_probe,
 720         .disconnect =   usb_serial_disconnect,
 721         .id_table =     id_table,
 722         .no_dynamic_id =        1,
 723 };
 724
 725 static struct usb_serial_driver ark3116_device = {
 726         .driver = {
 727                 .owner =        THIS_MODULE,
 728                 .name =         "ark3116",
 729         },
 730         .id_table =             id_table,
 731         .usb_driver =           &ark3116_driver,
 732         .num_ports =            1,
 733         .attach =               ark3116_attach,
 734         .release =              ark3116_release,
 735         .set_termios =          ark3116_set_termios,
 736         .init_termios =         ark3116_init_termios,
 737         .ioctl =                ark3116_ioctl,
 738         .tiocmget =             ark3116_tiocmget,
 739         .tiocmset =             ark3116_tiocmset,
 740         .get_icount =           ark3116_get_icount,
 741         .open =                 ark3116_open,
 742         .close =                ark3116_close,
 743         .break_ctl =            ark3116_break_ctl,
 744         .read_int_callback =    ark3116_read_int_callback,
 745         .process_read_urb =     ark3116_process_read_urb,
 746 };
 747
 748 static int __init ark3116_init(void)
 749 {
 750         int retval;
 751
 752         retval = usb_serial_register(&ark3116_device);
 753         if (retval)
 754                 return retval;
 755         retval = usb_register(&ark3116_driver);
 756         if (retval == 0) {
 757                 printk(KERN_INFO "%s:"
 758                        DRIVER_VERSION ":"
 759                        DRIVER_DESC "\n",
 760                        KBUILD_MODNAME);
 761         } else
 762                 usb_serial_deregister(&ark3116_device);
 763         return retval;
 764 }
 765
 766 static void __exit ark3116_exit(void)
 767 {
 768         usb_deregister(&ark3116_driver);
 769         usb_serial_deregister(&ark3116_device);
 770 }
 771
 772 module_init(ark3116_init);
 773 module_exit(ark3116_exit);
 774 MODULE_LICENSE("GPL");
 775
 776 MODULE_AUTHOR(DRIVER_AUTHOR);
 777 MODULE_DESCRIPTION(DRIVER_DESC);
 778
 779 module_param(debug, bool, S_IRUGO | S_IWUSR);
 780 MODULE_PARM_DESC(debug, "Enable debug");
 781
 782 /*
 783  * The following describes what I learned from studying the old
 784  * ark3116.c driver, disassembling the windows driver, and some lucky
 785  * guesses. Since I do not have any datasheet or other
 786  * documentation, inaccuracies are almost guaranteed.
 787  *
 788  * Some specs for the ARK3116 can be found here:
 789  * http://web.archive.org/web/20060318000438/
 790  *   www.arkmicro.com/en/products/view.php?id=10
 791  * On that page, 2 GPIO pins are mentioned: I assume these are the
 792  * OUT1 and OUT2 pins of the UART, so I added support for those
 793  * through the MCR. Since the pins are not available on my hardware,
 794  * I could not verify this.
 795  * Also, it states there is "on-chip hardware flow control". I have
 796  * discovered how to enable that. Unfortunately, I do not know how to
 797  * enable XON/XOFF (software) flow control, which would need support
 798  * from the chip as well to work. Because of the wording on the web
 799  * page there is a real possibility the chip simply does not support
 800  * software flow control.
 801  *
 802  * I got my ark3116 as part of a mobile phone adapter cable. On the
 803  * PCB, the following numbered contacts are present:
 804  *
 805  *  1:- +5V
 806  *  2:o DTR
 807  *  3:i RX
 808  *  4:i DCD
 809  *  5:o RTS
 810  *  6:o TX
 811  *  7:i RI
 812  *  8:i DSR
 813  * 10:- 0V
 814  * 11:i CTS
 815  *
 816  * On my chip, all signals seem to be 3.3V, but 5V tolerant. But that
 817  * may be different for the one you have ;-).
 818  *
 819  * The windows driver limits the registers to 0-F, so I assume there
 820  * are actually 16 present on the device.
 821  *
 822  * On an UART interrupt, 4 bytes of data come in on the interrupt
 823  * endpoint. The bytes are 0xe8 IIR LSR MSR.
 824  *
 825  * The baudrate seems to be generated from the 12MHz crystal, using
 826  * 4-times subsampling. So quot=12e6/(4*baud). Also see description
 827  * of register E.
 828  *
 829  * Registers 0-7:
 830  * These seem to be the same as for a regular 16450. The FCR is set
 831  * to UART_FCR_DMA_SELECT (0x8), I guess to enable transfers between
 832  * the UART and the USB bridge/DMA engine.
 833  *
 834  * Register 8:
 835  * By trial and error, I found out that bit 0 enables hardware CTS,
 836  * stopping TX when CTS is +5V. Bit 1 does the same for RTS, making
 837  * RTS +5V when the 3116 cannot transfer the data to the USB bus
 838  * (verified by disabling the reading URB). Note that as far as I can
 839  * tell, the windows driver does NOT use this, so there might be some
 840  * hardware bug or something.
 841  *
 842  * According to a patch provided here
 843  * (http://lkml.org/lkml/2009/7/26/56), the ARK3116 can also be used
 844  * as an IrDA dongle. Since I do not have such a thing, I could not
 845  * investigate that aspect. However, I can speculate ;-).
 846  *
 847  * - IrDA encodes data differently than RS232. Most likely, one of
 848  *   the bits in registers 9..E enables the IR ENDEC (encoder/decoder).
 849  * - Depending on the IR transceiver, the input and output need to be
 850  *   inverted, so there are probably bits for that as well.
 851  * - IrDA is half-duplex, so there should be a bit for selecting that.
 852  *
 853  * This still leaves at least two registers unaccounted for. Perhaps
 854  * The chip can do XON/XOFF or CRC in HW?
 855  *
 856  * Register 9:
 857  * Set to 0x00 for IrDA, when the baudrate is initialised.
 858  *
 859  * Register A:
 860  * Set to 0x01 for IrDA, at init.
 861  *
 862  * Register B:
 863  * Set to 0x01 for IrDA, 0x00 for RS232, at init.
 864  *
 865  * Register C:
 866  * Set to 00 for IrDA, at init.
 867  *
 868  * Register D:
 869  * Set to 0x41 for IrDA, at init.
 870  *
 871  * Register E:
 872  * Somekind of baudrate override. The windows driver seems to set
 873  * this to 0x00 for normal baudrates, 0x01 for 460800, 0x02 for 921600.
 874  * Since 460800 and 921600 cannot be obtained by dividing 3MHz by an integer,
 875  * it could be somekind of subdivisor thingy.
 876  * However,it does not seem to do anything: selecting 921600 (divisor 3,
 877  * reg E=2), still gets 1 MHz. I also checked if registers 9, C or F would
 878  * work, but they don't.
 879  *
 880  * Register F: unknown
 881  */