drivers/usb/serial/ch341.c

   1 /*
   2  * Copyright 2007, Frank A Kingswood <frank@kingswood-consulting.co.uk>
   3  * Copyright 2007, Werner Cornelius <werner@cornelius-consult.de>
   4  * Copyright 2009, Boris Hajduk <boris@hajduk.org>
   5  *
   6  * ch341.c implements a serial port driver for the Winchiphead CH341.
   7  *
   8  * The CH341 device can be used to implement an RS232 asynchronous
   9  * serial port, an IEEE-1284 parallel printer port or a memory-like
  10  * interface. In all cases the CH341 supports an I2C interface as well.
  11  * This driver only supports the asynchronous serial interface.
  12  *
  13  * This program is free software; you can redistribute it and/or
  14  * modify it under the terms of the GNU General Public License version
  15  * 2 as published by the Free Software Foundation.
  16  */
  17
  18 #include <linux/kernel.h>
  19 #include <linux/init.h>
  20 #include <linux/tty.h>
  21 #include <linux/module.h>
  22 #include <linux/usb.h>
  23 #include <linux/usb/serial.h>
  24 #include <linux/serial.h>
  25
  26 #define DEFAULT_BAUD_RATE 9600
  27 #define DEFAULT_TIMEOUT   1000
  28
  29 /* flags for IO-Bits */
  30 #define CH341_BIT_RTS (1 << 6)
  31 #define CH341_BIT_DTR (1 << 5)
  32
  33 /******************************/
  34 /* interrupt pipe definitions */
  35 /******************************/
  36 /* always 4 interrupt bytes */
  37 /* first irq byte normally 0x08 */
  38 /* second irq byte base 0x7d + below */
  39 /* third irq byte base 0x94 + below */
  40 /* fourth irq byte normally 0xee */
  41
  42 /* second interrupt byte */
  43 #define CH341_MULT_STAT 0x04 /* multiple status since last interrupt event */
  44
  45 /* status returned in third interrupt answer byte, inverted in data
  46    from irq */
  47 #define CH341_BIT_CTS 0x01
  48 #define CH341_BIT_DSR 0x02
  49 #define CH341_BIT_RI  0x04
  50 #define CH341_BIT_DCD 0x08
  51 #define CH341_BITS_MODEM_STAT 0x0f /* all bits */
  52
  53 /*******************************/
  54 /* baudrate calculation factor */
  55 /*******************************/
  56 #define CH341_BAUDBASE_FACTOR 1532620800
  57 #define CH341_BAUDBASE_DIVMAX 3
  58
  59 static int debug;
  60
  61 static struct usb_device_id id_table [] = {
  62         { USB_DEVICE(0x4348, 0x5523) },
  63         { USB_DEVICE(0x1a86, 0x7523) },
  64         { },
  65 };
  66 MODULE_DEVICE_TABLE(usb, id_table);
  67
  68 struct ch341_private {
  69         spinlock_t lock; /* access lock */
  70         wait_queue_head_t delta_msr_wait; /* wait queue for modem status */
  71         unsigned baud_rate; /* set baud rate */
  72         u8 line_control; /* set line control value RTS/DTR */
  73         u8 line_status; /* active status of modem control inputs */
  74         u8 multi_status_change; /* status changed multiple since last call */
  75 };
  76
  77 static int ch341_control_out(struct usb_device *dev, u8 request,
  78                              u16 value, u16 index)
  79 {
  80         int r;
  81         dbg("ch341_control_out(%02x,%02x,%04x,%04x)", USB_DIR_OUT|0x40,
  82                 (int)request, (int)value, (int)index);
  83
  84         r = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), request,
  85                             USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT,
  86                             value, index, NULL, 0, DEFAULT_TIMEOUT);
  87
  88         return r;
  89 }
  90
  91 static int ch341_control_in(struct usb_device *dev,
  92                             u8 request, u16 value, u16 index,
  93                             char *buf, unsigned bufsize)
  94 {
  95         int r;
  96         dbg("ch341_control_in(%02x,%02x,%04x,%04x,%p,%u)", USB_DIR_IN|0x40,
  97                 (int)request, (int)value, (int)index, buf, (int)bufsize);
  98
  99         r = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), request,
 100                             USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
 101                             value, index, buf, bufsize, DEFAULT_TIMEOUT);
 102         return r;
 103 }
 104
 105 static int ch341_set_baudrate(struct usb_device *dev,
 106                               struct ch341_private *priv)
 107 {
 108         short a, b;
 109         int r;
 110         unsigned long factor;
 111         short divisor;
 112
 113         dbg("ch341_set_baudrate(%d)", priv->baud_rate);
 114
 115         if (!priv->baud_rate)
 116                 return -EINVAL;
 117         factor = (CH341_BAUDBASE_FACTOR / priv->baud_rate);
 118         divisor = CH341_BAUDBASE_DIVMAX;
 119
 120         while ((factor > 0xfff0) && divisor) {
 121                 factor >>= 3;
 122                 divisor--;
 123         }
 124
 125         if (factor > 0xfff0)
 126                 return -EINVAL;
 127
 128         factor = 0x10000 - factor;
 129         a = (factor & 0xff00) | divisor;
 130         b = factor & 0xff;
 131
 132         r = ch341_control_out(dev, 0x9a, 0x1312, a);
 133         if (!r)
 134                 r = ch341_control_out(dev, 0x9a, 0x0f2c, b);
 135
 136         return r;
 137 }
 138
 139 static int ch341_set_handshake(struct usb_device *dev, u8 control)
 140 {
 141         dbg("ch341_set_handshake(0x%02x)", control);
 142         return ch341_control_out(dev, 0xa4, ~control, 0);
 143 }
 144
 145 static int ch341_get_status(struct usb_device *dev, struct ch341_private *priv)
 146 {
 147         char *buffer;
 148         int r;
 149         const unsigned size = 8;
 150         unsigned long flags;
 151
 152         dbg("ch341_get_status()");
 153
 154         buffer = kmalloc(size, GFP_KERNEL);
 155         if (!buffer)
 156                 return -ENOMEM;
 157
 158         r = ch341_control_in(dev, 0x95, 0x0706, 0, buffer, size);
 159         if (r < 0)
 160                 goto out;
 161
 162         /* setup the private status if available */
 163         if (r == 2) {
 164                 r = 0;
 165                 spin_lock_irqsave(&priv->lock, flags);
 166                 priv->line_status = (~(*buffer)) & CH341_BITS_MODEM_STAT;
 167                 priv->multi_status_change = 0;
 168                 spin_unlock_irqrestore(&priv->lock, flags);
 169         } else
 170                 r = -EPROTO;
 171
 172 out:    kfree(buffer);
 173         return r;
 174 }
 175
 176 /* -------------------------------------------------------------------------- */
 177
 178 static int ch341_configure(struct usb_device *dev, struct ch341_private *priv)
 179 {
 180         char *buffer;
 181         int r;
 182         const unsigned size = 8;
 183
 184         dbg("ch341_configure()");
 185
 186         buffer = kmalloc(size, GFP_KERNEL);
 187         if (!buffer)
 188                 return -ENOMEM;
 189
 190         /* expect two bytes 0x27 0x00 */
 191         r = ch341_control_in(dev, 0x5f, 0, 0, buffer, size);
 192         if (r < 0)
 193                 goto out;
 194
 195         r = ch341_control_out(dev, 0xa1, 0, 0);
 196         if (r < 0)
 197                 goto out;
 198
 199         r = ch341_set_baudrate(dev, priv);
 200         if (r < 0)
 201                 goto out;
 202
 203         /* expect two bytes 0x56 0x00 */
 204         r = ch341_control_in(dev, 0x95, 0x2518, 0, buffer, size);
 205         if (r < 0)
 206                 goto out;
 207
 208         r = ch341_control_out(dev, 0x9a, 0x2518, 0x0050);
 209         if (r < 0)
 210                 goto out;
 211
 212         /* expect 0xff 0xee */
 213         r = ch341_get_status(dev, priv);
 214         if (r < 0)
 215                 goto out;
 216
 217         r = ch341_control_out(dev, 0xa1, 0x501f, 0xd90a);
 218         if (r < 0)
 219                 goto out;
 220
 221         r = ch341_set_baudrate(dev, priv);
 222         if (r < 0)
 223                 goto out;
 224
 225         r = ch341_set_handshake(dev, priv->line_control);
 226         if (r < 0)
 227                 goto out;
 228
 229         /* expect 0x9f 0xee */
 230         r = ch341_get_status(dev, priv);
 231
 232 out:    kfree(buffer);
 233         return r;
 234 }
 235
 236 /* allocate private data */
 237 static int ch341_attach(struct usb_serial *serial)
 238 {
 239         struct ch341_private *priv;
 240         int r;
 241
 242         dbg("ch341_attach()");
 243
 244         /* private data */
 245         priv = kzalloc(sizeof(struct ch341_private), GFP_KERNEL);
 246         if (!priv)
 247                 return -ENOMEM;
 248
 249         spin_lock_init(&priv->lock);
 250         init_waitqueue_head(&priv->delta_msr_wait);
 251         priv->baud_rate = DEFAULT_BAUD_RATE;
 252         priv->line_control = CH341_BIT_RTS | CH341_BIT_DTR;
 253
 254         r = ch341_configure(serial->dev, priv);
 255         if (r < 0)
 256                 goto error;
 257
 258         usb_set_serial_port_data(serial->port[0], priv);
 259         return 0;
 260
 261 error:  kfree(priv);
 262         return r;
 263 }
 264
 265 static int ch341_carrier_raised(struct usb_serial_port *port)
 266 {
 267         struct ch341_private *priv = usb_get_serial_port_data(port);
 268         if (priv->line_status & CH341_BIT_DCD)
 269                 return 1;
 270         return 0;
 271 }
 272
 273 static void ch341_dtr_rts(struct usb_serial_port *port, int on)
 274 {
 275         struct ch341_private *priv = usb_get_serial_port_data(port);
 276         unsigned long flags;
 277
 278         dbg("%s - port %d", __func__, port->number);
 279         /* drop DTR and RTS */
 280         spin_lock_irqsave(&priv->lock, flags);
 281         if (on)
 282                 priv->line_control |= CH341_BIT_RTS | CH341_BIT_DTR;
 283         else
 284                 priv->line_control &= ~(CH341_BIT_RTS | CH341_BIT_DTR);
 285         spin_unlock_irqrestore(&priv->lock, flags);
 286         ch341_set_handshake(port->serial->dev, priv->line_control);
 287         wake_up_interruptible(&priv->delta_msr_wait);
 288 }
 289
 290 static void ch341_close(struct usb_serial_port *port)
 291 {
 292         dbg("%s - port %d", __func__, port->number);
 293
 294         /* shutdown our urbs */
 295         dbg("%s - shutting down urbs", __func__);
 296         usb_kill_urb(port->write_urb);
 297         usb_kill_urb(port->read_urb);
 298         usb_kill_urb(port->interrupt_in_urb);
 299 }
 300
 301
 302 /* open this device, set default parameters */
 303 static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port,
 304                                 struct file *filp)
 305 {
 306         struct usb_serial *serial = port->serial;
 307         struct ch341_private *priv = usb_get_serial_port_data(serial->port[0]);
 308         int r;
 309
 310         dbg("ch341_open()");
 311
 312         priv->baud_rate = DEFAULT_BAUD_RATE;
 313
 314         r = ch341_configure(serial->dev, priv);
 315         if (r)
 316                 goto out;
 317
 318         r = ch341_set_handshake(serial->dev, priv->line_control);
 319         if (r)
 320                 goto out;
 321
 322         r = ch341_set_baudrate(serial->dev, priv);
 323         if (r)
 324                 goto out;
 325
 326         dbg("%s - submitting interrupt urb", __func__);
 327         port->interrupt_in_urb->dev = serial->dev;
 328         r = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
 329         if (r) {
 330                 dev_err(&port->dev, "%s - failed submitting interrupt urb,"
 331                         " error %d\n", __func__, r);
 332                 ch341_close(port);
 333                 return -EPROTO;
 334         }
 335
 336         r = usb_serial_generic_open(tty, port, filp);
 337
 338 out:    return r;
 339 }
 340
 341 /* Old_termios contains the original termios settings and
 342  * tty->termios contains the new setting to be used.
 343  */
 344 static void ch341_set_termios(struct tty_struct *tty,
 345                 struct usb_serial_port *port, struct ktermios *old_termios)
 346 {
 347         struct ch341_private *priv = usb_get_serial_port_data(port);
 348         unsigned baud_rate;
 349         unsigned long flags;
 350
 351         dbg("ch341_set_termios()");
 352
 353         baud_rate = tty_get_baud_rate(tty);
 354
 355         priv->baud_rate = baud_rate;
 356
 357         if (baud_rate) {
 358                 spin_lock_irqsave(&priv->lock, flags);
 359                 priv->line_control |= (CH341_BIT_DTR | CH341_BIT_RTS);
 360                 spin_unlock_irqrestore(&priv->lock, flags);
 361                 ch341_set_baudrate(port->serial->dev, priv);
 362         } else {
 363                 spin_lock_irqsave(&priv->lock, flags);
 364                 priv->line_control &= ~(CH341_BIT_DTR | CH341_BIT_RTS);
 365                 spin_unlock_irqrestore(&priv->lock, flags);
 366         }
 367
 368         ch341_set_handshake(port->serial->dev, priv->line_control);
 369
 370         /* Unimplemented:
 371          * (cflag & CSIZE) : data bits [5, 8]
 372          * (cflag & PARENB) : parity {NONE, EVEN, ODD}
 373          * (cflag & CSTOPB) : stop bits [1, 2]
 374          */
 375 }
 376
 377 static int ch341_tiocmset(struct tty_struct *tty, struct file *file,
 378                           unsigned int set, unsigned int clear)
 379 {
 380         struct usb_serial_port *port = tty->driver_data;
 381         struct ch341_private *priv = usb_get_serial_port_data(port);
 382         unsigned long flags;
 383         u8 control;
 384
 385         spin_lock_irqsave(&priv->lock, flags);
 386         if (set & TIOCM_RTS)
 387                 priv->line_control |= CH341_BIT_RTS;
 388         if (set & TIOCM_DTR)
 389                 priv->line_control |= CH341_BIT_DTR;
 390         if (clear & TIOCM_RTS)
 391                 priv->line_control &= ~CH341_BIT_RTS;
 392         if (clear & TIOCM_DTR)
 393                 priv->line_control &= ~CH341_BIT_DTR;
 394         control = priv->line_control;
 395         spin_unlock_irqrestore(&priv->lock, flags);
 396
 397         return ch341_set_handshake(port->serial->dev, control);
 398 }
 399
 400 static void ch341_read_int_callback(struct urb *urb)
 401 {
 402         struct usb_serial_port *port = (struct usb_serial_port *) urb->context;
 403         unsigned char *data = urb->transfer_buffer;
 404         unsigned int actual_length = urb->actual_length;
 405         int status;
 406
 407         dbg("%s (%d)", __func__, port->number);
 408
 409         switch (urb->status) {
 410         case 0:
 411                 /* success */
 412                 break;
 413         case -ECONNRESET:
 414         case -ENOENT:
 415         case -ESHUTDOWN:
 416                 /* this urb is terminated, clean up */
 417                 dbg("%s - urb shutting down with status: %d", __func__,
 418                     urb->status);
 419                 return;
 420         default:
 421                 dbg("%s - nonzero urb status received: %d", __func__,
 422                     urb->status);
 423                 goto exit;
 424         }
 425
 426         usb_serial_debug_data(debug, &port->dev, __func__,
 427                               urb->actual_length, urb->transfer_buffer);
 428
 429         if (actual_length >= 4) {
 430                 struct ch341_private *priv = usb_get_serial_port_data(port);
 431                 unsigned long flags;
 432
 433                 spin_lock_irqsave(&priv->lock, flags);
 434                 priv->line_status = (~(data[2])) & CH341_BITS_MODEM_STAT;
 435                 if ((data[1] & CH341_MULT_STAT))
 436                         priv->multi_status_change = 1;
 437                 spin_unlock_irqrestore(&priv->lock, flags);
 438                 wake_up_interruptible(&priv->delta_msr_wait);
 439         }
 440
 441 exit:
 442         status = usb_submit_urb(urb, GFP_ATOMIC);
 443         if (status)
 444                 dev_err(&urb->dev->dev,
 445                         "%s - usb_submit_urb failed with result %d\n",
 446                         __func__, status);
 447 }
 448
 449 static int wait_modem_info(struct usb_serial_port *port, unsigned int arg)
 450 {
 451         struct ch341_private *priv = usb_get_serial_port_data(port);
 452         unsigned long flags;
 453         u8 prevstatus;
 454         u8 status;
 455         u8 changed;
 456         u8 multi_change = 0;
 457
 458         spin_lock_irqsave(&priv->lock, flags);
 459         prevstatus = priv->line_status;
 460         priv->multi_status_change = 0;
 461         spin_unlock_irqrestore(&priv->lock, flags);
 462
 463         while (!multi_change) {
 464                 interruptible_sleep_on(&priv->delta_msr_wait);
 465                 /* see if a signal did it */
 466                 if (signal_pending(current))
 467                         return -ERESTARTSYS;
 468
 469                 spin_lock_irqsave(&priv->lock, flags);
 470                 status = priv->line_status;
 471                 multi_change = priv->multi_status_change;
 472                 spin_unlock_irqrestore(&priv->lock, flags);
 473
 474                 changed = prevstatus ^ status;
 475
 476                 if (((arg & TIOCM_RNG) && (changed & CH341_BIT_RI)) ||
 477                     ((arg & TIOCM_DSR) && (changed & CH341_BIT_DSR)) ||
 478                     ((arg & TIOCM_CD)  && (changed & CH341_BIT_DCD)) ||
 479                     ((arg & TIOCM_CTS) && (changed & CH341_BIT_CTS))) {
 480                         return 0;
 481                 }
 482                 prevstatus = status;
 483         }
 484
 485         return 0;
 486 }
 487
 488 /*static int ch341_ioctl(struct usb_serial_port *port, struct file *file,*/
 489 static int ch341_ioctl(struct tty_struct *tty, struct file *file,
 490                         unsigned int cmd, unsigned long arg)
 491 {
 492         struct usb_serial_port *port = tty->driver_data;
 493         dbg("%s (%d) cmd = 0x%04x", __func__, port->number, cmd);
 494
 495         switch (cmd) {
 496         case TIOCMIWAIT:
 497                 dbg("%s (%d) TIOCMIWAIT", __func__,  port->number);
 498                 return wait_modem_info(port, arg);
 499
 500         default:
 501                 dbg("%s not supported = 0x%04x", __func__, cmd);
 502                 break;
 503         }
 504
 505         return -ENOIOCTLCMD;
 506 }
 507
 508 static int ch341_tiocmget(struct tty_struct *tty, struct file *file)
 509 {
 510         struct usb_serial_port *port = tty->driver_data;
 511         struct ch341_private *priv = usb_get_serial_port_data(port);
 512         unsigned long flags;
 513         u8 mcr;
 514         u8 status;
 515         unsigned int result;
 516
 517         dbg("%s (%d)", __func__, port->number);
 518
 519         spin_lock_irqsave(&priv->lock, flags);
 520         mcr = priv->line_control;
 521         status = priv->line_status;
 522         spin_unlock_irqrestore(&priv->lock, flags);
 523
 524         result = ((mcr & CH341_BIT_DTR)         ? TIOCM_DTR : 0)
 525                   | ((mcr & CH341_BIT_RTS)      ? TIOCM_RTS : 0)
 526                   | ((status & CH341_BIT_CTS)   ? TIOCM_CTS : 0)
 527                   | ((status & CH341_BIT_DSR)   ? TIOCM_DSR : 0)
 528                   | ((status & CH341_BIT_RI)    ? TIOCM_RI  : 0)
 529                   | ((status & CH341_BIT_DCD)   ? TIOCM_CD  : 0);
 530
 531         dbg("%s - result = %x", __func__, result);
 532
 533         return result;
 534 }
 535
 536
 537 static int ch341_reset_resume(struct usb_interface *intf)
 538 {
 539         struct usb_device *dev = interface_to_usbdev(intf);
 540         struct usb_serial *serial = NULL;
 541         struct ch341_private *priv;
 542
 543         serial = usb_get_intfdata(intf);
 544         priv = usb_get_serial_port_data(serial->port[0]);
 545
 546         /*reconfigure ch341 serial port after bus-reset*/
 547         ch341_configure(dev, priv);
 548
 549         usb_serial_resume(intf);
 550
 551         return 0;
 552 }
 553
 554 static struct usb_driver ch341_driver = {
 555         .name           = "ch341",
 556         .probe          = usb_serial_probe,
 557         .disconnect     = usb_serial_disconnect,
 558         .suspend        = usb_serial_suspend,
 559         .resume         = usb_serial_resume,
 560         .reset_resume   = ch341_reset_resume,
 561         .id_table       = id_table,
 562         .no_dynamic_id  = 1,
 563         .supports_autosuspend = 1,
 564 };
 565
 566 static struct usb_serial_driver ch341_device = {
 567         .driver = {
 568                 .owner  = THIS_MODULE,
 569                 .name   = "ch341-uart",
 570         },
 571         .id_table          = id_table,
 572         .usb_driver        = &ch341_driver,
 573         .num_ports         = 1,
 574         .open              = ch341_open,
 575         .dtr_rts           = ch341_dtr_rts,
 576         .carrier_raised    = ch341_carrier_raised,
 577         .close             = ch341_close,
 578         .ioctl             = ch341_ioctl,
 579         .set_termios       = ch341_set_termios,
 580         .tiocmget          = ch341_tiocmget,
 581         .tiocmset          = ch341_tiocmset,
 582         .read_int_callback = ch341_read_int_callback,
 583         .attach            = ch341_attach,
 584 };
 585
 586 static int __init ch341_init(void)
 587 {
 588         int retval;
 589
 590         retval = usb_serial_register(&ch341_device);
 591         if (retval)
 592                 return retval;
 593         retval = usb_register(&ch341_driver);
 594         if (retval)
 595                 usb_serial_deregister(&ch341_device);
 596         return retval;
 597 }
 598
 599 static void __exit ch341_exit(void)
 600 {
 601         usb_deregister(&ch341_driver);
 602         usb_serial_deregister(&ch341_device);
 603 }
 604
 605 module_init(ch341_init);
 606 module_exit(ch341_exit);
 607 MODULE_LICENSE("GPL");
 608
 609 module_param(debug, bool, S_IRUGO | S_IWUSR);
 610 MODULE_PARM_DESC(debug, "Debug enabled or not");
 611
 612 /* EOF ch341.c */