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/ioctl.h>
  27 #include <linux/tty.h>
  28 #include <linux/slab.h>
  29 #include <linux/tty_flip.h>
  30 #include <linux/module.h>
  31 #include <linux/usb.h>
  32 #include <linux/usb/serial.h>
  33 #include <linux/serial.h>
  34 #include <linux/serial_reg.h>
  35 #include <linux/uaccess.h>
  36 #include <linux/mutex.h>
  37 #include <linux/spinlock.h>
  38
  39 #define DRIVER_AUTHOR "Bart Hartgers <bart.hartgers+ark3116@gmail.com>"
  40 #define DRIVER_DESC "USB ARK3116 serial/IrDA driver"
  41 #define DRIVER_DEV_DESC "ARK3116 RS232/IrDA"
  42 #define DRIVER_NAME "ark3116"
  43
  44 /* usb timeout of 1 second */
  45 #define ARK_TIMEOUT 1000
  46
  47 static const struct usb_device_id id_table[] = {
  48         { USB_DEVICE(0x6547, 0x0232) },
  49         { USB_DEVICE(0x18ec, 0x3118) },         /* USB to IrDA adapter */
  50         { },
  51 };
  52 MODULE_DEVICE_TABLE(usb, id_table);
  53
  54 static int is_irda(struct usb_serial *serial)
  55 {
  56         struct usb_device *dev = serial->dev;
  57         if (le16_to_cpu(dev->descriptor.idVendor) == 0x18ec &&
  58                         le16_to_cpu(dev->descriptor.idProduct) == 0x3118)
  59                 return 1;
  60         return 0;
  61 }
  62
  63 struct ark3116_private {
  64         int                     irda;   /* 1 for irda device */
  65
  66         /* protects hw register updates */
  67         struct mutex            hw_lock;
  68
  69         int                     quot;   /* baudrate divisor */
  70         __u32                   lcr;    /* line control register value */
  71         __u32                   hcr;    /* handshake control register (0x8)
  72                                          * value */
  73         __u32                   mcr;    /* modem control register value */
  74
  75         /* protects the status values below */
  76         spinlock_t              status_lock;
  77         __u32                   msr;    /* modem status register value */
  78         __u32                   lsr;    /* line status register value */
  79 };
  80
  81 static int ark3116_write_reg(struct usb_serial *serial,
  82                              unsigned reg, __u8 val)
  83 {
  84         int result;
  85          /* 0xfe 0x40 are magic values taken from original driver */
  86         result = usb_control_msg(serial->dev,
  87                                  usb_sndctrlpipe(serial->dev, 0),
  88                                  0xfe, 0x40, val, reg,
  89                                  NULL, 0, ARK_TIMEOUT);
  90         return result;
  91 }
  92
  93 static int ark3116_read_reg(struct usb_serial *serial,
  94                             unsigned reg, unsigned char *buf)
  95 {
  96         int result;
  97         /* 0xfe 0xc0 are magic values taken from original driver */
  98         result = usb_control_msg(serial->dev,
  99                                  usb_rcvctrlpipe(serial->dev, 0),
 100                                  0xfe, 0xc0, 0, reg,
 101                                  buf, 1, ARK_TIMEOUT);
 102         if (result < 0)
 103                 return result;
 104         else
 105                 return buf[0];
 106 }
 107
 108 static inline int calc_divisor(int bps)
 109 {
 110         /* Original ark3116 made some exceptions in rounding here
 111          * because windows did the same. Assume that is not really
 112          * necessary.
 113          * Crystal is 12MHz, probably because of USB, but we divide by 4?
 114          */
 115         return (12000000 + 2*bps) / (4*bps);
 116 }
 117
 118 static int ark3116_attach(struct usb_serial *serial)
 119 {
 120         /* make sure we have our end-points */
 121         if ((serial->num_bulk_in == 0) ||
 122             (serial->num_bulk_out == 0) ||
 123             (serial->num_interrupt_in == 0)) {
 124                 dev_err(&serial->dev->dev,
 125                         "%s - missing endpoint - "
 126                         "bulk in: %d, bulk out: %d, int in %d\n",
 127                         KBUILD_MODNAME,
 128                         serial->num_bulk_in,
 129                         serial->num_bulk_out,
 130                         serial->num_interrupt_in);
 131                 return -EINVAL;
 132         }
 133
 134         return 0;
 135 }
 136
 137 static int ark3116_port_probe(struct usb_serial_port *port)
 138 {
 139         struct usb_serial *serial = port->serial;
 140         struct ark3116_private *priv;
 141
 142         priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 143         if (!priv)
 144                 return -ENOMEM;
 145
 146         mutex_init(&priv->hw_lock);
 147         spin_lock_init(&priv->status_lock);
 148
 149         priv->irda = is_irda(serial);
 150
 151         usb_set_serial_port_data(port, priv);
 152
 153         /* setup the hardware */
 154         ark3116_write_reg(serial, UART_IER, 0);
 155         /* disable DMA */
 156         ark3116_write_reg(serial, UART_FCR, 0);
 157         /* handshake control */
 158         priv->hcr = 0;
 159         ark3116_write_reg(serial, 0x8     , 0);
 160         /* modem control */
 161         priv->mcr = 0;
 162         ark3116_write_reg(serial, UART_MCR, 0);
 163
 164         if (!(priv->irda)) {
 165                 ark3116_write_reg(serial, 0xb , 0);
 166         } else {
 167                 ark3116_write_reg(serial, 0xb , 1);
 168                 ark3116_write_reg(serial, 0xc , 0);
 169                 ark3116_write_reg(serial, 0xd , 0x41);
 170                 ark3116_write_reg(serial, 0xa , 1);
 171         }
 172
 173         /* setup baudrate */
 174         ark3116_write_reg(serial, UART_LCR, UART_LCR_DLAB);
 175
 176         /* setup for 9600 8N1 */
 177         priv->quot = calc_divisor(9600);
 178         ark3116_write_reg(serial, UART_DLL, priv->quot & 0xff);
 179         ark3116_write_reg(serial, UART_DLM, (priv->quot>>8) & 0xff);
 180
 181         priv->lcr = UART_LCR_WLEN8;
 182         ark3116_write_reg(serial, UART_LCR, UART_LCR_WLEN8);
 183
 184         ark3116_write_reg(serial, 0xe, 0);
 185
 186         if (priv->irda)
 187                 ark3116_write_reg(serial, 0x9, 0);
 188
 189         dev_info(&serial->dev->dev,
 190                 "%s using %s mode\n",
 191                 KBUILD_MODNAME,
 192                 priv->irda ? "IrDA" : "RS232");
 193         return 0;
 194 }
 195
 196 static int ark3116_port_remove(struct usb_serial_port *port)
 197 {
 198         struct ark3116_private *priv = usb_get_serial_port_data(port);
 199
 200         /* device is closed, so URBs and DMA should be down */
 201         mutex_destroy(&priv->hw_lock);
 202         kfree(priv);
 203
 204         return 0;
 205 }
 206
 207 static void ark3116_init_termios(struct tty_struct *tty)
 208 {
 209         struct ktermios *termios = &tty->termios;
 210         *termios = tty_std_termios;
 211         termios->c_cflag = B9600 | CS8
 212                                       | CREAD | HUPCL | CLOCAL;
 213         termios->c_ispeed = 9600;
 214         termios->c_ospeed = 9600;
 215 }
 216
 217 static void ark3116_set_termios(struct tty_struct *tty,
 218                                 struct usb_serial_port *port,
 219                                 struct ktermios *old_termios)
 220 {
 221         struct usb_serial *serial = port->serial;
 222         struct ark3116_private *priv = usb_get_serial_port_data(port);
 223         struct ktermios *termios = &tty->termios;
 224         unsigned int cflag = termios->c_cflag;
 225         int bps = tty_get_baud_rate(tty);
 226         int quot;
 227         __u8 lcr, hcr, eval;
 228
 229         /* set data bit count */
 230         switch (cflag & CSIZE) {
 231         case CS5:
 232                 lcr = UART_LCR_WLEN5;
 233                 break;
 234         case CS6:
 235                 lcr = UART_LCR_WLEN6;
 236                 break;
 237         case CS7:
 238                 lcr = UART_LCR_WLEN7;
 239                 break;
 240         default:
 241         case CS8:
 242                 lcr = UART_LCR_WLEN8;
 243                 break;
 244         }
 245         if (cflag & CSTOPB)
 246                 lcr |= UART_LCR_STOP;
 247         if (cflag & PARENB)
 248                 lcr |= UART_LCR_PARITY;
 249         if (!(cflag & PARODD))
 250                 lcr |= UART_LCR_EPAR;
 251 #ifdef CMSPAR
 252         if (cflag & CMSPAR)
 253                 lcr |= UART_LCR_SPAR;
 254 #endif
 255         /* handshake control */
 256         hcr = (cflag & CRTSCTS) ? 0x03 : 0x00;
 257
 258         /* calc baudrate */
 259         dev_dbg(&port->dev, "%s - setting bps to %d\n", __func__, bps);
 260         eval = 0;
 261         switch (bps) {
 262         case 0:
 263                 quot = calc_divisor(9600);
 264                 break;
 265         default:
 266                 if ((bps < 75) || (bps > 3000000))
 267                         bps = 9600;
 268                 quot = calc_divisor(bps);
 269                 break;
 270         case 460800:
 271                 eval = 1;
 272                 quot = calc_divisor(bps);
 273                 break;
 274         case 921600:
 275                 eval = 2;
 276                 quot = calc_divisor(bps);
 277                 break;
 278         }
 279
 280         /* Update state: synchronize */
 281         mutex_lock(&priv->hw_lock);
 282
 283         /* keep old LCR_SBC bit */
 284         lcr |= (priv->lcr & UART_LCR_SBC);
 285
 286         dev_dbg(&port->dev, "%s - setting hcr:0x%02x,lcr:0x%02x,quot:%d\n",
 287                 __func__, hcr, lcr, quot);
 288
 289         /* handshake control */
 290         if (priv->hcr != hcr) {
 291                 priv->hcr = hcr;
 292                 ark3116_write_reg(serial, 0x8, hcr);
 293         }
 294
 295         /* baudrate */
 296         if (priv->quot != quot) {
 297                 priv->quot = quot;
 298                 priv->lcr = lcr; /* need to write lcr anyway */
 299
 300                 /* disable DMA since transmit/receive is
 301                  * shadowed by UART_DLL
 302                  */
 303                 ark3116_write_reg(serial, UART_FCR, 0);
 304
 305                 ark3116_write_reg(serial, UART_LCR,
 306                                   lcr|UART_LCR_DLAB);
 307                 ark3116_write_reg(serial, UART_DLL, quot & 0xff);
 308                 ark3116_write_reg(serial, UART_DLM, (quot>>8) & 0xff);
 309
 310                 /* restore lcr */
 311                 ark3116_write_reg(serial, UART_LCR, lcr);
 312                 /* magic baudrate thingy: not sure what it does,
 313                  * but windows does this as well.
 314                  */
 315                 ark3116_write_reg(serial, 0xe, eval);
 316
 317                 /* enable DMA */
 318                 ark3116_write_reg(serial, UART_FCR, UART_FCR_DMA_SELECT);
 319         } else if (priv->lcr != lcr) {
 320                 priv->lcr = lcr;
 321                 ark3116_write_reg(serial, UART_LCR, lcr);
 322         }
 323
 324         mutex_unlock(&priv->hw_lock);
 325
 326         /* check for software flow control */
 327         if (I_IXOFF(tty) || I_IXON(tty)) {
 328                 dev_warn(&serial->dev->dev,
 329                          "%s: don't know how to do software flow control\n",
 330                          KBUILD_MODNAME);
 331         }
 332
 333         /* Don't rewrite B0 */
 334         if (tty_termios_baud_rate(termios))
 335                 tty_termios_encode_baud_rate(termios, bps, bps);
 336 }
 337
 338 static void ark3116_close(struct usb_serial_port *port)
 339 {
 340         struct usb_serial *serial = port->serial;
 341
 342         /* disable DMA */
 343         ark3116_write_reg(serial, UART_FCR, 0);
 344
 345         /* deactivate interrupts */
 346         ark3116_write_reg(serial, UART_IER, 0);
 347
 348         usb_serial_generic_close(port);
 349         if (serial->num_interrupt_in)
 350                 usb_kill_urb(port->interrupt_in_urb);
 351 }
 352
 353 static int ark3116_open(struct tty_struct *tty, struct usb_serial_port *port)
 354 {
 355         struct ark3116_private *priv = usb_get_serial_port_data(port);
 356         struct usb_serial *serial = port->serial;
 357         unsigned char *buf;
 358         int result;
 359
 360         buf = kmalloc(1, GFP_KERNEL);
 361         if (buf == NULL)
 362                 return -ENOMEM;
 363
 364         result = usb_serial_generic_open(tty, port);
 365         if (result) {
 366                 dev_dbg(&port->dev,
 367                         "%s - usb_serial_generic_open failed: %d\n",
 368                         __func__, result);
 369                 goto err_out;
 370         }
 371
 372         /* remove any data still left: also clears error state */
 373         ark3116_read_reg(serial, UART_RX, buf);
 374
 375         /* read modem status */
 376         priv->msr = ark3116_read_reg(serial, UART_MSR, buf);
 377         /* read line status */
 378         priv->lsr = ark3116_read_reg(serial, UART_LSR, buf);
 379
 380         result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
 381         if (result) {
 382                 dev_err(&port->dev, "submit irq_in urb failed %d\n",
 383                         result);
 384                 ark3116_close(port);
 385                 goto err_out;
 386         }
 387
 388         /* activate interrupts */
 389         ark3116_write_reg(port->serial, UART_IER, UART_IER_MSI|UART_IER_RLSI);
 390
 391         /* enable DMA */
 392         ark3116_write_reg(port->serial, UART_FCR, UART_FCR_DMA_SELECT);
 393
 394         /* setup termios */
 395         if (tty)
 396                 ark3116_set_termios(tty, port, NULL);
 397
 398 err_out:
 399         kfree(buf);
 400         return result;
 401 }
 402
 403 static int ark3116_ioctl(struct tty_struct *tty,
 404                          unsigned int cmd, unsigned long arg)
 405 {
 406         struct usb_serial_port *port = tty->driver_data;
 407         struct serial_struct serstruct;
 408         void __user *user_arg = (void __user *)arg;
 409
 410         switch (cmd) {
 411         case TIOCGSERIAL:
 412                 /* XXX: Some of these values are probably wrong. */
 413                 memset(&serstruct, 0, sizeof(serstruct));
 414                 serstruct.type = PORT_16654;
 415                 serstruct.line = port->minor;
 416                 serstruct.port = port->port_number;
 417                 serstruct.custom_divisor = 0;
 418                 serstruct.baud_base = 460800;
 419
 420                 if (copy_to_user(user_arg, &serstruct, sizeof(serstruct)))
 421                         return -EFAULT;
 422
 423                 return 0;
 424         case TIOCSSERIAL:
 425                 if (copy_from_user(&serstruct, user_arg, sizeof(serstruct)))
 426                         return -EFAULT;
 427                 return 0;
 428         }
 429
 430         return -ENOIOCTLCMD;
 431 }
 432
 433 static int ark3116_tiocmget(struct tty_struct *tty)
 434 {
 435         struct usb_serial_port *port = tty->driver_data;
 436         struct ark3116_private *priv = usb_get_serial_port_data(port);
 437         __u32 status;
 438         __u32 ctrl;
 439         unsigned long flags;
 440
 441         mutex_lock(&priv->hw_lock);
 442         ctrl = priv->mcr;
 443         mutex_unlock(&priv->hw_lock);
 444
 445         spin_lock_irqsave(&priv->status_lock, flags);
 446         status = priv->msr;
 447         spin_unlock_irqrestore(&priv->status_lock, flags);
 448
 449         return  (status & UART_MSR_DSR  ? TIOCM_DSR  : 0) |
 450                 (status & UART_MSR_CTS  ? TIOCM_CTS  : 0) |
 451                 (status & UART_MSR_RI   ? TIOCM_RI   : 0) |
 452                 (status & UART_MSR_DCD  ? TIOCM_CD   : 0) |
 453                 (ctrl   & UART_MCR_DTR  ? TIOCM_DTR  : 0) |
 454                 (ctrl   & UART_MCR_RTS  ? TIOCM_RTS  : 0) |
 455                 (ctrl   & UART_MCR_OUT1 ? TIOCM_OUT1 : 0) |
 456                 (ctrl   & UART_MCR_OUT2 ? TIOCM_OUT2 : 0);
 457 }
 458
 459 static int ark3116_tiocmset(struct tty_struct *tty,
 460                         unsigned set, unsigned clr)
 461 {
 462         struct usb_serial_port *port = tty->driver_data;
 463         struct ark3116_private *priv = usb_get_serial_port_data(port);
 464
 465         /* we need to take the mutex here, to make sure that the value
 466          * in priv->mcr is actually the one that is in the hardware
 467          */
 468
 469         mutex_lock(&priv->hw_lock);
 470
 471         if (set & TIOCM_RTS)
 472                 priv->mcr |= UART_MCR_RTS;
 473         if (set & TIOCM_DTR)
 474                 priv->mcr |= UART_MCR_DTR;
 475         if (set & TIOCM_OUT1)
 476                 priv->mcr |= UART_MCR_OUT1;
 477         if (set & TIOCM_OUT2)
 478                 priv->mcr |= UART_MCR_OUT2;
 479         if (clr & TIOCM_RTS)
 480                 priv->mcr &= ~UART_MCR_RTS;
 481         if (clr & TIOCM_DTR)
 482                 priv->mcr &= ~UART_MCR_DTR;
 483         if (clr & TIOCM_OUT1)
 484                 priv->mcr &= ~UART_MCR_OUT1;
 485         if (clr & TIOCM_OUT2)
 486                 priv->mcr &= ~UART_MCR_OUT2;
 487
 488         ark3116_write_reg(port->serial, UART_MCR, priv->mcr);
 489
 490         mutex_unlock(&priv->hw_lock);
 491
 492         return 0;
 493 }
 494
 495 static void ark3116_break_ctl(struct tty_struct *tty, int break_state)
 496 {
 497         struct usb_serial_port *port = tty->driver_data;
 498         struct ark3116_private *priv = usb_get_serial_port_data(port);
 499
 500         /* LCR is also used for other things: protect access */
 501         mutex_lock(&priv->hw_lock);
 502
 503         if (break_state)
 504                 priv->lcr |= UART_LCR_SBC;
 505         else
 506                 priv->lcr &= ~UART_LCR_SBC;
 507
 508         ark3116_write_reg(port->serial, UART_LCR, priv->lcr);
 509
 510         mutex_unlock(&priv->hw_lock);
 511 }
 512
 513 static void ark3116_update_msr(struct usb_serial_port *port, __u8 msr)
 514 {
 515         struct ark3116_private *priv = usb_get_serial_port_data(port);
 516         unsigned long flags;
 517
 518         spin_lock_irqsave(&priv->status_lock, flags);
 519         priv->msr = msr;
 520         spin_unlock_irqrestore(&priv->status_lock, flags);
 521
 522         if (msr & UART_MSR_ANY_DELTA) {
 523                 /* update input line counters */
 524                 if (msr & UART_MSR_DCTS)
 525                         port->icount.cts++;
 526                 if (msr & UART_MSR_DDSR)
 527                         port->icount.dsr++;
 528                 if (msr & UART_MSR_DDCD)
 529                         port->icount.dcd++;
 530                 if (msr & UART_MSR_TERI)
 531                         port->icount.rng++;
 532                 wake_up_interruptible(&port->port.delta_msr_wait);
 533         }
 534 }
 535
 536 static void ark3116_update_lsr(struct usb_serial_port *port, __u8 lsr)
 537 {
 538         struct ark3116_private *priv = usb_get_serial_port_data(port);
 539         unsigned long flags;
 540
 541         spin_lock_irqsave(&priv->status_lock, flags);
 542         /* combine bits */
 543         priv->lsr |= lsr;
 544         spin_unlock_irqrestore(&priv->status_lock, flags);
 545
 546         if (lsr&UART_LSR_BRK_ERROR_BITS) {
 547                 if (lsr & UART_LSR_BI)
 548                         port->icount.brk++;
 549                 if (lsr & UART_LSR_FE)
 550                         port->icount.frame++;
 551                 if (lsr & UART_LSR_PE)
 552                         port->icount.parity++;
 553                 if (lsr & UART_LSR_OE)
 554                         port->icount.overrun++;
 555         }
 556 }
 557
 558 static void ark3116_read_int_callback(struct urb *urb)
 559 {
 560         struct usb_serial_port *port = urb->context;
 561         int status = urb->status;
 562         const __u8 *data = urb->transfer_buffer;
 563         int result;
 564
 565         switch (status) {
 566         case -ECONNRESET:
 567         case -ENOENT:
 568         case -ESHUTDOWN:
 569                 /* this urb is terminated, clean up */
 570                 dev_dbg(&port->dev, "%s - urb shutting down with status: %d\n",
 571                         __func__, status);
 572                 return;
 573         default:
 574                 dev_dbg(&port->dev, "%s - nonzero urb status received: %d\n",
 575                         __func__, status);
 576                 break;
 577         case 0: /* success */
 578                 /* discovered this by trail and error... */
 579                 if ((urb->actual_length == 4) && (data[0] == 0xe8)) {
 580                         const __u8 id = data[1]&UART_IIR_ID;
 581                         dev_dbg(&port->dev, "%s: iir=%02x\n", __func__, data[1]);
 582                         if (id == UART_IIR_MSI) {
 583                                 dev_dbg(&port->dev, "%s: msr=%02x\n",
 584                                         __func__, data[3]);
 585                                 ark3116_update_msr(port, data[3]);
 586                                 break;
 587                         } else if (id == UART_IIR_RLSI) {
 588                                 dev_dbg(&port->dev, "%s: lsr=%02x\n",
 589                                         __func__, data[2]);
 590                                 ark3116_update_lsr(port, data[2]);
 591                                 break;
 592                         }
 593                 }
 594                 /*
 595                  * Not sure what this data meant...
 596                  */
 597                 usb_serial_debug_data(&port->dev, __func__,
 598                                       urb->actual_length,
 599                                       urb->transfer_buffer);
 600                 break;
 601         }
 602
 603         result = usb_submit_urb(urb, GFP_ATOMIC);
 604         if (result)
 605                 dev_err(&urb->dev->dev,
 606                         "%s - Error %d submitting interrupt urb\n",
 607                         __func__, result);
 608 }
 609
 610
 611 /* Data comes in via the bulk (data) URB, errors/interrupts via the int URB.
 612  * This means that we cannot be sure which data byte has an associated error
 613  * condition, so we report an error for all data in the next bulk read.
 614  *
 615  * Actually, there might even be a window between the bulk data leaving the
 616  * ark and reading/resetting the lsr in the read_bulk_callback where an
 617  * interrupt for the next data block could come in.
 618  * Without somekind of ordering on the ark, we would have to report the
 619  * error for the next block of data as well...
 620  * For now, let's pretend this can't happen.
 621  */
 622 static void ark3116_process_read_urb(struct urb *urb)
 623 {
 624         struct usb_serial_port *port = urb->context;
 625         struct ark3116_private *priv = usb_get_serial_port_data(port);
 626         unsigned char *data = urb->transfer_buffer;
 627         char tty_flag = TTY_NORMAL;
 628         unsigned long flags;
 629         __u32 lsr;
 630
 631         /* update line status */
 632         spin_lock_irqsave(&priv->status_lock, flags);
 633         lsr = priv->lsr;
 634         priv->lsr &= ~UART_LSR_BRK_ERROR_BITS;
 635         spin_unlock_irqrestore(&priv->status_lock, flags);
 636
 637         if (!urb->actual_length)
 638                 return;
 639
 640         if (lsr & UART_LSR_BRK_ERROR_BITS) {
 641                 if (lsr & UART_LSR_BI)
 642                         tty_flag = TTY_BREAK;
 643                 else if (lsr & UART_LSR_PE)
 644                         tty_flag = TTY_PARITY;
 645                 else if (lsr & UART_LSR_FE)
 646                         tty_flag = TTY_FRAME;
 647
 648                 /* overrun is special, not associated with a char */
 649                 if (lsr & UART_LSR_OE)
 650                         tty_insert_flip_char(&port->port, 0, TTY_OVERRUN);
 651         }
 652         tty_insert_flip_string_fixed_flag(&port->port, data, tty_flag,
 653                                                         urb->actual_length);
 654         tty_flip_buffer_push(&port->port);
 655 }
 656
 657 static struct usb_serial_driver ark3116_device = {
 658         .driver = {
 659                 .owner =        THIS_MODULE,
 660                 .name =         "ark3116",
 661         },
 662         .id_table =             id_table,
 663         .num_ports =            1,
 664         .attach =               ark3116_attach,
 665         .port_probe =           ark3116_port_probe,
 666         .port_remove =          ark3116_port_remove,
 667         .set_termios =          ark3116_set_termios,
 668         .init_termios =         ark3116_init_termios,
 669         .ioctl =                ark3116_ioctl,
 670         .tiocmget =             ark3116_tiocmget,
 671         .tiocmset =             ark3116_tiocmset,
 672         .tiocmiwait =           usb_serial_generic_tiocmiwait,
 673         .get_icount =           usb_serial_generic_get_icount,
 674         .open =                 ark3116_open,
 675         .close =                ark3116_close,
 676         .break_ctl =            ark3116_break_ctl,
 677         .read_int_callback =    ark3116_read_int_callback,
 678         .process_read_urb =     ark3116_process_read_urb,
 679 };
 680
 681 static struct usb_serial_driver * const serial_drivers[] = {
 682         &ark3116_device, NULL
 683 };
 684
 685 module_usb_serial_driver(serial_drivers, id_table);
 686
 687 MODULE_LICENSE("GPL");
 688
 689 MODULE_AUTHOR(DRIVER_AUTHOR);
 690 MODULE_DESCRIPTION(DRIVER_DESC);
 691
 692 /*
 693  * The following describes what I learned from studying the old
 694  * ark3116.c driver, disassembling the windows driver, and some lucky
 695  * guesses. Since I do not have any datasheet or other
 696  * documentation, inaccuracies are almost guaranteed.
 697  *
 698  * Some specs for the ARK3116 can be found here:
 699  * http://web.archive.org/web/20060318000438/
 700  *   www.arkmicro.com/en/products/view.php?id=10
 701  * On that page, 2 GPIO pins are mentioned: I assume these are the
 702  * OUT1 and OUT2 pins of the UART, so I added support for those
 703  * through the MCR. Since the pins are not available on my hardware,
 704  * I could not verify this.
 705  * Also, it states there is "on-chip hardware flow control". I have
 706  * discovered how to enable that. Unfortunately, I do not know how to
 707  * enable XON/XOFF (software) flow control, which would need support
 708  * from the chip as well to work. Because of the wording on the web
 709  * page there is a real possibility the chip simply does not support
 710  * software flow control.
 711  *
 712  * I got my ark3116 as part of a mobile phone adapter cable. On the
 713  * PCB, the following numbered contacts are present:
 714  *
 715  *  1:- +5V
 716  *  2:o DTR
 717  *  3:i RX
 718  *  4:i DCD
 719  *  5:o RTS
 720  *  6:o TX
 721  *  7:i RI
 722  *  8:i DSR
 723  * 10:- 0V
 724  * 11:i CTS
 725  *
 726  * On my chip, all signals seem to be 3.3V, but 5V tolerant. But that
 727  * may be different for the one you have ;-).
 728  *
 729  * The windows driver limits the registers to 0-F, so I assume there
 730  * are actually 16 present on the device.
 731  *
 732  * On an UART interrupt, 4 bytes of data come in on the interrupt
 733  * endpoint. The bytes are 0xe8 IIR LSR MSR.
 734  *
 735  * The baudrate seems to be generated from the 12MHz crystal, using
 736  * 4-times subsampling. So quot=12e6/(4*baud). Also see description
 737  * of register E.
 738  *
 739  * Registers 0-7:
 740  * These seem to be the same as for a regular 16450. The FCR is set
 741  * to UART_FCR_DMA_SELECT (0x8), I guess to enable transfers between
 742  * the UART and the USB bridge/DMA engine.
 743  *
 744  * Register 8:
 745  * By trial and error, I found out that bit 0 enables hardware CTS,
 746  * stopping TX when CTS is +5V. Bit 1 does the same for RTS, making
 747  * RTS +5V when the 3116 cannot transfer the data to the USB bus
 748  * (verified by disabling the reading URB). Note that as far as I can
 749  * tell, the windows driver does NOT use this, so there might be some
 750  * hardware bug or something.
 751  *
 752  * According to a patch provided here
 753  * (http://lkml.org/lkml/2009/7/26/56), the ARK3116 can also be used
 754  * as an IrDA dongle. Since I do not have such a thing, I could not
 755  * investigate that aspect. However, I can speculate ;-).
 756  *
 757  * - IrDA encodes data differently than RS232. Most likely, one of
 758  *   the bits in registers 9..E enables the IR ENDEC (encoder/decoder).
 759  * - Depending on the IR transceiver, the input and output need to be
 760  *   inverted, so there are probably bits for that as well.
 761  * - IrDA is half-duplex, so there should be a bit for selecting that.
 762  *
 763  * This still leaves at least two registers unaccounted for. Perhaps
 764  * The chip can do XON/XOFF or CRC in HW?
 765  *
 766  * Register 9:
 767  * Set to 0x00 for IrDA, when the baudrate is initialised.
 768  *
 769  * Register A:
 770  * Set to 0x01 for IrDA, at init.
 771  *
 772  * Register B:
 773  * Set to 0x01 for IrDA, 0x00 for RS232, at init.
 774  *
 775  * Register C:
 776  * Set to 00 for IrDA, at init.
 777  *
 778  * Register D:
 779  * Set to 0x41 for IrDA, at init.
 780  *
 781  * Register E:
 782  * Somekind of baudrate override. The windows driver seems to set
 783  * this to 0x00 for normal baudrates, 0x01 for 460800, 0x02 for 921600.
 784  * Since 460800 and 921600 cannot be obtained by dividing 3MHz by an integer,
 785  * it could be somekind of subdivisor thingy.
 786  * However,it does not seem to do anything: selecting 921600 (divisor 3,
 787  * reg E=2), still gets 1 MHz. I also checked if registers 9, C or F would
 788  * work, but they don't.
 789  *
 790  * Register F: unknown
 791  */