drivers/usb/serial/ch341.c

   1 /*
   2  * Copyright 2007, Frank A Kingswood <frank@kingswood-consulting.co.uk>
   3  * Copyright 2007, Werner Cornelius <werner@cornelius-consult.de>
   4  * Copyright 2009, Boris Hajduk <boris@hajduk.org>
   5  *
   6  * ch341.c implements a serial port driver for the Winchiphead CH341.
   7  *
   8  * The CH341 device can be used to implement an RS232 asynchronous
   9  * serial port, an IEEE-1284 parallel printer port or a memory-like
  10  * interface. In all cases the CH341 supports an I2C interface as well.
  11  * This driver only supports the asynchronous serial interface.
  12  *
  13  * This program is free software; you can redistribute it and/or
  14  * modify it under the terms of the GNU General Public License version
  15  * 2 as published by the Free Software Foundation.
  16  */
  17
  18 #include <linux/kernel.h>
  19 #include <linux/init.h>
  20 #include <linux/tty.h>
  21 #include <linux/module.h>
  22 #include <linux/slab.h>
  23 #include <linux/usb.h>
  24 #include <linux/usb/serial.h>
  25 #include <linux/serial.h>
  26 #include <asm/unaligned.h>
  27
  28 #define DEFAULT_BAUD_RATE 9600
  29 #define DEFAULT_TIMEOUT   1000
  30
  31 /* flags for IO-Bits */
  32 #define CH341_BIT_RTS (1 << 6)
  33 #define CH341_BIT_DTR (1 << 5)
  34
  35 /******************************/
  36 /* interrupt pipe definitions */
  37 /******************************/
  38 /* always 4 interrupt bytes */
  39 /* first irq byte normally 0x08 */
  40 /* second irq byte base 0x7d + below */
  41 /* third irq byte base 0x94 + below */
  42 /* fourth irq byte normally 0xee */
  43
  44 /* second interrupt byte */
  45 #define CH341_MULT_STAT 0x04 /* multiple status since last interrupt event */
  46
  47 /* status returned in third interrupt answer byte, inverted in data
  48    from irq */
  49 #define CH341_BIT_CTS 0x01
  50 #define CH341_BIT_DSR 0x02
  51 #define CH341_BIT_RI  0x04
  52 #define CH341_BIT_DCD 0x08
  53 #define CH341_BITS_MODEM_STAT 0x0f /* all bits */
  54
  55 /*******************************/
  56 /* baudrate calculation factor */
  57 /*******************************/
  58 #define CH341_BAUDBASE_FACTOR 1532620800
  59 #define CH341_BAUDBASE_DIVMAX 3
  60
  61 /* Break support - the information used to implement this was gleaned from
  62  * the Net/FreeBSD uchcom.c driver by Takanori Watanabe.  Domo arigato.
  63  */
  64
  65 #define CH341_REQ_WRITE_REG    0x9A
  66 #define CH341_REQ_READ_REG     0x95
  67 #define CH341_REG_BREAK1       0x05
  68 #define CH341_REG_BREAK2       0x18
  69 #define CH341_NBREAK_BITS_REG1 0x01
  70 #define CH341_NBREAK_BITS_REG2 0x40
  71
  72
  73 static const struct usb_device_id id_table[] = {
  74         { USB_DEVICE(0x4348, 0x5523) },
  75         { USB_DEVICE(0x1a86, 0x7523) },
  76         { USB_DEVICE(0x1a86, 0x5523) },
  77         { },
  78 };
  79 MODULE_DEVICE_TABLE(usb, id_table);
  80
  81 struct ch341_private {
  82         spinlock_t lock; /* access lock */
  83         wait_queue_head_t delta_msr_wait; /* wait queue for modem status */
  84         unsigned baud_rate; /* set baud rate */
  85         u8 line_control; /* set line control value RTS/DTR */
  86         u8 line_status; /* active status of modem control inputs */
  87         u8 multi_status_change; /* status changed multiple since last call */
  88 };
  89
  90 static int ch341_control_out(struct usb_device *dev, u8 request,
  91                              u16 value, u16 index)
  92 {
  93         int r;
  94
  95         dev_dbg(&dev->dev, "ch341_control_out(%02x,%02x,%04x,%04x)\n",
  96                 USB_DIR_OUT|0x40, (int)request, (int)value, (int)index);
  97
  98         r = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), request,
  99                             USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT,
 100                             value, index, NULL, 0, DEFAULT_TIMEOUT);
 101
 102         return r;
 103 }
 104
 105 static int ch341_control_in(struct usb_device *dev,
 106                             u8 request, u16 value, u16 index,
 107                             char *buf, unsigned bufsize)
 108 {
 109         int r;
 110
 111         dev_dbg(&dev->dev, "ch341_control_in(%02x,%02x,%04x,%04x,%p,%u)\n",
 112                 USB_DIR_IN|0x40, (int)request, (int)value, (int)index, buf,
 113                 (int)bufsize);
 114
 115         r = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), request,
 116                             USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
 117                             value, index, buf, bufsize, DEFAULT_TIMEOUT);
 118         return r;
 119 }
 120
 121 static int ch341_set_baudrate(struct usb_device *dev,
 122                               struct ch341_private *priv)
 123 {
 124         short a, b;
 125         int r;
 126         unsigned long factor;
 127         short divisor;
 128
 129         if (!priv->baud_rate)
 130                 return -EINVAL;
 131         factor = (CH341_BAUDBASE_FACTOR / priv->baud_rate);
 132         divisor = CH341_BAUDBASE_DIVMAX;
 133
 134         while ((factor > 0xfff0) && divisor) {
 135                 factor >>= 3;
 136                 divisor--;
 137         }
 138
 139         if (factor > 0xfff0)
 140                 return -EINVAL;
 141
 142         factor = 0x10000 - factor;
 143         a = (factor & 0xff00) | divisor;
 144         b = factor & 0xff;
 145
 146         r = ch341_control_out(dev, 0x9a, 0x1312, a);
 147         if (!r)
 148                 r = ch341_control_out(dev, 0x9a, 0x0f2c, b);
 149
 150         return r;
 151 }
 152
 153 static int ch341_set_handshake(struct usb_device *dev, u8 control)
 154 {
 155         return ch341_control_out(dev, 0xa4, ~control, 0);
 156 }
 157
 158 static int ch341_get_status(struct usb_device *dev, struct ch341_private *priv)
 159 {
 160         char *buffer;
 161         int r;
 162         const unsigned size = 8;
 163         unsigned long flags;
 164
 165         buffer = kmalloc(size, GFP_KERNEL);
 166         if (!buffer)
 167                 return -ENOMEM;
 168
 169         r = ch341_control_in(dev, 0x95, 0x0706, 0, buffer, size);
 170         if (r < 0)
 171                 goto out;
 172
 173         /* setup the private status if available */
 174         if (r == 2) {
 175                 r = 0;
 176                 spin_lock_irqsave(&priv->lock, flags);
 177                 priv->line_status = (~(*buffer)) & CH341_BITS_MODEM_STAT;
 178                 priv->multi_status_change = 0;
 179                 spin_unlock_irqrestore(&priv->lock, flags);
 180         } else
 181                 r = -EPROTO;
 182
 183 out:    kfree(buffer);
 184         return r;
 185 }
 186
 187 /* -------------------------------------------------------------------------- */
 188
 189 static int ch341_configure(struct usb_device *dev, struct ch341_private *priv)
 190 {
 191         char *buffer;
 192         int r;
 193         const unsigned size = 8;
 194
 195         buffer = kmalloc(size, GFP_KERNEL);
 196         if (!buffer)
 197                 return -ENOMEM;
 198
 199         /* expect two bytes 0x27 0x00 */
 200         r = ch341_control_in(dev, 0x5f, 0, 0, buffer, size);
 201         if (r < 0)
 202                 goto out;
 203
 204         r = ch341_control_out(dev, 0xa1, 0, 0);
 205         if (r < 0)
 206                 goto out;
 207
 208         r = ch341_set_baudrate(dev, priv);
 209         if (r < 0)
 210                 goto out;
 211
 212         /* expect two bytes 0x56 0x00 */
 213         r = ch341_control_in(dev, 0x95, 0x2518, 0, buffer, size);
 214         if (r < 0)
 215                 goto out;
 216
 217         r = ch341_control_out(dev, 0x9a, 0x2518, 0x0050);
 218         if (r < 0)
 219                 goto out;
 220
 221         /* expect 0xff 0xee */
 222         r = ch341_get_status(dev, priv);
 223         if (r < 0)
 224                 goto out;
 225
 226         r = ch341_control_out(dev, 0xa1, 0x501f, 0xd90a);
 227         if (r < 0)
 228                 goto out;
 229
 230         r = ch341_set_baudrate(dev, priv);
 231         if (r < 0)
 232                 goto out;
 233
 234         r = ch341_set_handshake(dev, priv->line_control);
 235         if (r < 0)
 236                 goto out;
 237
 238         /* expect 0x9f 0xee */
 239         r = ch341_get_status(dev, priv);
 240
 241 out:    kfree(buffer);
 242         return r;
 243 }
 244
 245 static int ch341_port_probe(struct usb_serial_port *port)
 246 {
 247         struct ch341_private *priv;
 248         int r;
 249
 250         priv = kzalloc(sizeof(struct ch341_private), GFP_KERNEL);
 251         if (!priv)
 252                 return -ENOMEM;
 253
 254         spin_lock_init(&priv->lock);
 255         init_waitqueue_head(&priv->delta_msr_wait);
 256         priv->baud_rate = DEFAULT_BAUD_RATE;
 257         priv->line_control = CH341_BIT_RTS | CH341_BIT_DTR;
 258
 259         r = ch341_configure(port->serial->dev, priv);
 260         if (r < 0)
 261                 goto error;
 262
 263         usb_set_serial_port_data(port, priv);
 264         return 0;
 265
 266 error:  kfree(priv);
 267         return r;
 268 }
 269
 270 static int ch341_port_remove(struct usb_serial_port *port)
 271 {
 272         struct ch341_private *priv;
 273
 274         priv = usb_get_serial_port_data(port);
 275         kfree(priv);
 276
 277         return 0;
 278 }
 279
 280 static int ch341_carrier_raised(struct usb_serial_port *port)
 281 {
 282         struct ch341_private *priv = usb_get_serial_port_data(port);
 283         if (priv->line_status & CH341_BIT_DCD)
 284                 return 1;
 285         return 0;
 286 }
 287
 288 static void ch341_dtr_rts(struct usb_serial_port *port, int on)
 289 {
 290         struct ch341_private *priv = usb_get_serial_port_data(port);
 291         unsigned long flags;
 292
 293         /* drop DTR and RTS */
 294         spin_lock_irqsave(&priv->lock, flags);
 295         if (on)
 296                 priv->line_control |= CH341_BIT_RTS | CH341_BIT_DTR;
 297         else
 298                 priv->line_control &= ~(CH341_BIT_RTS | CH341_BIT_DTR);
 299         spin_unlock_irqrestore(&priv->lock, flags);
 300         ch341_set_handshake(port->serial->dev, priv->line_control);
 301         wake_up_interruptible(&priv->delta_msr_wait);
 302 }
 303
 304 static void ch341_close(struct usb_serial_port *port)
 305 {
 306         usb_serial_generic_close(port);
 307         usb_kill_urb(port->interrupt_in_urb);
 308 }
 309
 310
 311 /* open this device, set default parameters */
 312 static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port)
 313 {
 314         struct usb_serial *serial = port->serial;
 315         struct ch341_private *priv = usb_get_serial_port_data(port);
 316         int r;
 317
 318         priv->baud_rate = DEFAULT_BAUD_RATE;
 319
 320         r = ch341_configure(serial->dev, priv);
 321         if (r)
 322                 goto out;
 323
 324         r = ch341_set_handshake(serial->dev, priv->line_control);
 325         if (r)
 326                 goto out;
 327
 328         r = ch341_set_baudrate(serial->dev, priv);
 329         if (r)
 330                 goto out;
 331
 332         dev_dbg(&port->dev, "%s - submitting interrupt urb", __func__);
 333         r = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
 334         if (r) {
 335                 dev_err(&port->dev, "%s - failed submitting interrupt urb,"
 336                         " error %d\n", __func__, r);
 337                 ch341_close(port);
 338                 goto out;
 339         }
 340
 341         r = usb_serial_generic_open(tty, port);
 342
 343 out:    return r;
 344 }
 345
 346 /* Old_termios contains the original termios settings and
 347  * tty->termios contains the new setting to be used.
 348  */
 349 static void ch341_set_termios(struct tty_struct *tty,
 350                 struct usb_serial_port *port, struct ktermios *old_termios)
 351 {
 352         struct ch341_private *priv = usb_get_serial_port_data(port);
 353         unsigned baud_rate;
 354         unsigned long flags;
 355
 356         baud_rate = tty_get_baud_rate(tty);
 357
 358         priv->baud_rate = baud_rate;
 359
 360         if (baud_rate) {
 361                 spin_lock_irqsave(&priv->lock, flags);
 362                 priv->line_control |= (CH341_BIT_DTR | CH341_BIT_RTS);
 363                 spin_unlock_irqrestore(&priv->lock, flags);
 364                 ch341_set_baudrate(port->serial->dev, priv);
 365         } else {
 366                 spin_lock_irqsave(&priv->lock, flags);
 367                 priv->line_control &= ~(CH341_BIT_DTR | CH341_BIT_RTS);
 368                 spin_unlock_irqrestore(&priv->lock, flags);
 369         }
 370
 371         ch341_set_handshake(port->serial->dev, priv->line_control);
 372
 373         /* Unimplemented:
 374          * (cflag & CSIZE) : data bits [5, 8]
 375          * (cflag & PARENB) : parity {NONE, EVEN, ODD}
 376          * (cflag & CSTOPB) : stop bits [1, 2]
 377          */
 378 }
 379
 380 static void ch341_break_ctl(struct tty_struct *tty, int break_state)
 381 {
 382         const uint16_t ch341_break_reg =
 383                 CH341_REG_BREAK1 | ((uint16_t) CH341_REG_BREAK2 << 8);
 384         struct usb_serial_port *port = tty->driver_data;
 385         int r;
 386         uint16_t reg_contents;
 387         uint8_t *break_reg;
 388
 389         break_reg = kmalloc(2, GFP_KERNEL);
 390         if (!break_reg) {
 391                 dev_err(&port->dev, "%s - kmalloc failed\n", __func__);
 392                 return;
 393         }
 394
 395         r = ch341_control_in(port->serial->dev, CH341_REQ_READ_REG,
 396                         ch341_break_reg, 0, break_reg, 2);
 397         if (r < 0) {
 398                 dev_err(&port->dev, "%s - USB control read error (%d)\n",
 399                                 __func__, r);
 400                 goto out;
 401         }
 402         dev_dbg(&port->dev, "%s - initial ch341 break register contents - reg1: %x, reg2: %x\n",
 403                 __func__, break_reg[0], break_reg[1]);
 404         if (break_state != 0) {
 405                 dev_dbg(&port->dev, "%s - Enter break state requested\n", __func__);
 406                 break_reg[0] &= ~CH341_NBREAK_BITS_REG1;
 407                 break_reg[1] &= ~CH341_NBREAK_BITS_REG2;
 408         } else {
 409                 dev_dbg(&port->dev, "%s - Leave break state requested\n", __func__);
 410                 break_reg[0] |= CH341_NBREAK_BITS_REG1;
 411                 break_reg[1] |= CH341_NBREAK_BITS_REG2;
 412         }
 413         dev_dbg(&port->dev, "%s - New ch341 break register contents - reg1: %x, reg2: %x\n",
 414                 __func__, break_reg[0], break_reg[1]);
 415         reg_contents = get_unaligned_le16(break_reg);
 416         r = ch341_control_out(port->serial->dev, CH341_REQ_WRITE_REG,
 417                         ch341_break_reg, reg_contents);
 418         if (r < 0)
 419                 dev_err(&port->dev, "%s - USB control write error (%d)\n",
 420                                 __func__, r);
 421 out:
 422         kfree(break_reg);
 423 }
 424
 425 static int ch341_tiocmset(struct tty_struct *tty,
 426                           unsigned int set, unsigned int clear)
 427 {
 428         struct usb_serial_port *port = tty->driver_data;
 429         struct ch341_private *priv = usb_get_serial_port_data(port);
 430         unsigned long flags;
 431         u8 control;
 432
 433         spin_lock_irqsave(&priv->lock, flags);
 434         if (set & TIOCM_RTS)
 435                 priv->line_control |= CH341_BIT_RTS;
 436         if (set & TIOCM_DTR)
 437                 priv->line_control |= CH341_BIT_DTR;
 438         if (clear & TIOCM_RTS)
 439                 priv->line_control &= ~CH341_BIT_RTS;
 440         if (clear & TIOCM_DTR)
 441                 priv->line_control &= ~CH341_BIT_DTR;
 442         control = priv->line_control;
 443         spin_unlock_irqrestore(&priv->lock, flags);
 444
 445         return ch341_set_handshake(port->serial->dev, control);
 446 }
 447
 448 static void ch341_read_int_callback(struct urb *urb)
 449 {
 450         struct usb_serial_port *port = (struct usb_serial_port *) urb->context;
 451         unsigned char *data = urb->transfer_buffer;
 452         unsigned int actual_length = urb->actual_length;
 453         int status;
 454
 455         switch (urb->status) {
 456         case 0:
 457                 /* success */
 458                 break;
 459         case -ECONNRESET:
 460         case -ENOENT:
 461         case -ESHUTDOWN:
 462                 /* this urb is terminated, clean up */
 463                 dev_dbg(&urb->dev->dev, "%s - urb shutting down with status: %d\n",
 464                         __func__, urb->status);
 465                 return;
 466         default:
 467                 dev_dbg(&urb->dev->dev, "%s - nonzero urb status received: %d\n",
 468                         __func__, urb->status);
 469                 goto exit;
 470         }
 471
 472         usb_serial_debug_data(&port->dev, __func__,
 473                               urb->actual_length, urb->transfer_buffer);
 474
 475         if (actual_length >= 4) {
 476                 struct ch341_private *priv = usb_get_serial_port_data(port);
 477                 unsigned long flags;
 478                 u8 prev_line_status = priv->line_status;
 479
 480                 spin_lock_irqsave(&priv->lock, flags);
 481                 priv->line_status = (~(data[2])) & CH341_BITS_MODEM_STAT;
 482                 if ((data[1] & CH341_MULT_STAT))
 483                         priv->multi_status_change = 1;
 484                 spin_unlock_irqrestore(&priv->lock, flags);
 485
 486                 if ((priv->line_status ^ prev_line_status) & CH341_BIT_DCD) {
 487                         struct tty_struct *tty = tty_port_tty_get(&port->port);
 488                         if (tty)
 489                                 usb_serial_handle_dcd_change(port, tty,
 490                                             priv->line_status & CH341_BIT_DCD);
 491                         tty_kref_put(tty);
 492                 }
 493
 494                 wake_up_interruptible(&priv->delta_msr_wait);
 495         }
 496
 497 exit:
 498         status = usb_submit_urb(urb, GFP_ATOMIC);
 499         if (status)
 500                 dev_err(&urb->dev->dev,
 501                         "%s - usb_submit_urb failed with result %d\n",
 502                         __func__, status);
 503 }
 504
 505 static int wait_modem_info(struct usb_serial_port *port, unsigned int arg)
 506 {
 507         struct ch341_private *priv = usb_get_serial_port_data(port);
 508         unsigned long flags;
 509         u8 prevstatus;
 510         u8 status;
 511         u8 changed;
 512         u8 multi_change = 0;
 513
 514         spin_lock_irqsave(&priv->lock, flags);
 515         prevstatus = priv->line_status;
 516         priv->multi_status_change = 0;
 517         spin_unlock_irqrestore(&priv->lock, flags);
 518
 519         while (!multi_change) {
 520                 interruptible_sleep_on(&priv->delta_msr_wait);
 521                 /* see if a signal did it */
 522                 if (signal_pending(current))
 523                         return -ERESTARTSYS;
 524
 525                 spin_lock_irqsave(&priv->lock, flags);
 526                 status = priv->line_status;
 527                 multi_change = priv->multi_status_change;
 528                 spin_unlock_irqrestore(&priv->lock, flags);
 529
 530                 changed = prevstatus ^ status;
 531
 532                 if (((arg & TIOCM_RNG) && (changed & CH341_BIT_RI)) ||
 533                     ((arg & TIOCM_DSR) && (changed & CH341_BIT_DSR)) ||
 534                     ((arg & TIOCM_CD)  && (changed & CH341_BIT_DCD)) ||
 535                     ((arg & TIOCM_CTS) && (changed & CH341_BIT_CTS))) {
 536                         return 0;
 537                 }
 538                 prevstatus = status;
 539         }
 540
 541         return 0;
 542 }
 543
 544 static int ch341_ioctl(struct tty_struct *tty,
 545                         unsigned int cmd, unsigned long arg)
 546 {
 547         struct usb_serial_port *port = tty->driver_data;
 548
 549         dev_dbg(&port->dev, "%s (%d) cmd = 0x%04x\n", __func__, port->number, cmd);
 550
 551         switch (cmd) {
 552         case TIOCMIWAIT:
 553                 dev_dbg(&port->dev, "%s (%d) TIOCMIWAIT\n", __func__,  port->number);
 554                 return wait_modem_info(port, arg);
 555
 556         default:
 557                 dev_dbg(&port->dev, "%s not supported = 0x%04x\n", __func__, cmd);
 558                 break;
 559         }
 560
 561         return -ENOIOCTLCMD;
 562 }
 563
 564 static int ch341_tiocmget(struct tty_struct *tty)
 565 {
 566         struct usb_serial_port *port = tty->driver_data;
 567         struct ch341_private *priv = usb_get_serial_port_data(port);
 568         unsigned long flags;
 569         u8 mcr;
 570         u8 status;
 571         unsigned int result;
 572
 573         spin_lock_irqsave(&priv->lock, flags);
 574         mcr = priv->line_control;
 575         status = priv->line_status;
 576         spin_unlock_irqrestore(&priv->lock, flags);
 577
 578         result = ((mcr & CH341_BIT_DTR)         ? TIOCM_DTR : 0)
 579                   | ((mcr & CH341_BIT_RTS)      ? TIOCM_RTS : 0)
 580                   | ((status & CH341_BIT_CTS)   ? TIOCM_CTS : 0)
 581                   | ((status & CH341_BIT_DSR)   ? TIOCM_DSR : 0)
 582                   | ((status & CH341_BIT_RI)    ? TIOCM_RI  : 0)
 583                   | ((status & CH341_BIT_DCD)   ? TIOCM_CD  : 0);
 584
 585         dev_dbg(&port->dev, "%s - result = %x\n", __func__, result);
 586
 587         return result;
 588 }
 589
 590 static int ch341_reset_resume(struct usb_serial *serial)
 591 {
 592         struct ch341_private *priv;
 593
 594         priv = usb_get_serial_port_data(serial->port[0]);
 595
 596         /* reconfigure ch341 serial port after bus-reset */
 597         ch341_configure(serial->dev, priv);
 598
 599         return 0;
 600 }
 601
 602 static struct usb_serial_driver ch341_device = {
 603         .driver = {
 604                 .owner  = THIS_MODULE,
 605                 .name   = "ch341-uart",
 606         },
 607         .id_table          = id_table,
 608         .num_ports         = 1,
 609         .open              = ch341_open,
 610         .dtr_rts           = ch341_dtr_rts,
 611         .carrier_raised    = ch341_carrier_raised,
 612         .close             = ch341_close,
 613         .ioctl             = ch341_ioctl,
 614         .set_termios       = ch341_set_termios,
 615         .break_ctl         = ch341_break_ctl,
 616         .tiocmget          = ch341_tiocmget,
 617         .tiocmset          = ch341_tiocmset,
 618         .read_int_callback = ch341_read_int_callback,
 619         .port_probe        = ch341_port_probe,
 620         .port_remove       = ch341_port_remove,
 621         .reset_resume      = ch341_reset_resume,
 622 };
 623
 624 static struct usb_serial_driver * const serial_drivers[] = {
 625         &ch341_device, NULL
 626 };
 627
 628 module_usb_serial_driver(serial_drivers, id_table);
 629
 630 MODULE_LICENSE("GPL");