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/tty.h>
  20 #include <linux/module.h>
  21 #include <linux/slab.h>
  22 #include <linux/usb.h>
  23 #include <linux/usb/serial.h>
  24 #include <linux/serial.h>
  25 #include <asm/unaligned.h>
  26
  27 #define DEFAULT_BAUD_RATE 9600
  28 #define DEFAULT_TIMEOUT   1000
  29
  30 /* flags for IO-Bits */
  31 #define CH341_BIT_RTS (1 << 6)
  32 #define CH341_BIT_DTR (1 << 5)
  33
  34 /******************************/
  35 /* interrupt pipe definitions */
  36 /******************************/
  37 /* always 4 interrupt bytes */
  38 /* first irq byte normally 0x08 */
  39 /* second irq byte base 0x7d + below */
  40 /* third irq byte base 0x94 + below */
  41 /* fourth irq byte normally 0xee */
  42
  43 /* second interrupt byte */
  44 #define CH341_MULT_STAT 0x04 /* multiple status since last interrupt event */
  45
  46 /* status returned in third interrupt answer byte, inverted in data
  47    from irq */
  48 #define CH341_BIT_CTS 0x01
  49 #define CH341_BIT_DSR 0x02
  50 #define CH341_BIT_RI  0x04
  51 #define CH341_BIT_DCD 0x08
  52 #define CH341_BITS_MODEM_STAT 0x0f /* all bits */
  53
  54 /*******************************/
  55 /* baudrate calculation factor */
  56 /*******************************/
  57 #define CH341_BAUDBASE_FACTOR 1532620800
  58 #define CH341_BAUDBASE_DIVMAX 3
  59
  60 /* Break support - the information used to implement this was gleaned from
  61  * the Net/FreeBSD uchcom.c driver by Takanori Watanabe.  Domo arigato.
  62  */
  63
  64 #define CH341_REQ_WRITE_REG    0x9A
  65 #define CH341_REQ_READ_REG     0x95
  66 #define CH341_REG_BREAK1       0x05
  67 #define CH341_REG_BREAK2       0x18
  68 #define CH341_NBREAK_BITS_REG1 0x01
  69 #define CH341_NBREAK_BITS_REG2 0x40
  70
  71
  72 static const struct usb_device_id id_table[] = {
  73         { USB_DEVICE(0x1a86, 0x5512) },
  74         { USB_DEVICE(0x1a86, 0x5523) },
  75         { USB_DEVICE(0x1a86, 0x7522) },
  76         { USB_DEVICE(0x1a86, 0x7523) },
  77         { USB_DEVICE(0x4348, 0x5523) },
  78         { USB_DEVICE(0x9986, 0x7523) },
  79         { },
  80 };
  81 MODULE_DEVICE_TABLE(usb, id_table);
  82
  83 struct ch341_private {
  84         spinlock_t lock; /* access lock */
  85         unsigned baud_rate; /* set baud rate */
  86         u8 line_control; /* set line control value RTS/DTR */
  87         u8 line_status; /* active status of modem control inputs */
  88 };
  89
  90 static void ch341_set_termios(struct tty_struct *tty,
  91                               struct usb_serial_port *port,
  92                               struct ktermios *old_termios);
  93
  94 static int ch341_control_out(struct usb_device *dev, u8 request,
  95                              u16 value, u16 index)
  96 {
  97         int r;
  98
  99         dev_dbg(&dev->dev, "ch341_control_out(%02x,%02x,%04x,%04x)\n",
 100                 USB_DIR_OUT|0x40, (int)request, (int)value, (int)index);
 101
 102         r = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), request,
 103                             USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT,
 104                             value, index, NULL, 0, DEFAULT_TIMEOUT);
 105         if (r < 0)
 106                 dev_err(&dev->dev, "failed to send control message: %d\n", r);
 107
 108         return r;
 109 }
 110
 111 static int ch341_control_in(struct usb_device *dev,
 112                             u8 request, u16 value, u16 index,
 113                             char *buf, unsigned bufsize)
 114 {
 115         int r;
 116
 117         dev_dbg(&dev->dev, "ch341_control_in(%02x,%02x,%04x,%04x,%p,%u)\n",
 118                 USB_DIR_IN|0x40, (int)request, (int)value, (int)index, buf,
 119                 (int)bufsize);
 120
 121         r = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), request,
 122                             USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
 123                             value, index, buf, bufsize, DEFAULT_TIMEOUT);
 124         if (r < (int)bufsize) {
 125                 if (r >= 0) {
 126                         dev_err(&dev->dev,
 127                                 "short control message received (%d < %u)\n",
 128                                 r, bufsize);
 129                         r = -EIO;
 130                 }
 131
 132                 dev_err(&dev->dev, "failed to receive control message: %d\n",
 133                         r);
 134                 return r;
 135         }
 136
 137         return 0;
 138 }
 139
 140 static int ch341_set_baudrate(struct usb_device *dev,
 141                               struct ch341_private *priv)
 142 {
 143         short a, b;
 144         int r;
 145         unsigned long factor;
 146         short divisor;
 147
 148         if (!priv->baud_rate)
 149                 return -EINVAL;
 150         factor = (CH341_BAUDBASE_FACTOR / priv->baud_rate);
 151         divisor = CH341_BAUDBASE_DIVMAX;
 152
 153         while ((factor > 0xfff0) && divisor) {
 154                 factor >>= 3;
 155                 divisor--;
 156         }
 157
 158         if (factor > 0xfff0)
 159                 return -EINVAL;
 160
 161         factor = 0x10000 - factor;
 162         a = (factor & 0xff00) | divisor;
 163         b = factor & 0xff;
 164
 165         r = ch341_control_out(dev, 0x9a, 0x1312, a);
 166         if (!r)
 167                 r = ch341_control_out(dev, 0x9a, 0x0f2c, b);
 168
 169         return r;
 170 }
 171
 172 static int ch341_set_handshake(struct usb_device *dev, u8 control)
 173 {
 174         return ch341_control_out(dev, 0xa4, ~control, 0);
 175 }
 176
 177 static int ch341_get_status(struct usb_device *dev, struct ch341_private *priv)
 178 {
 179         const unsigned int size = 2;
 180         char *buffer;
 181         int r;
 182         unsigned long flags;
 183
 184         buffer = kmalloc(size, GFP_KERNEL);
 185         if (!buffer)
 186                 return -ENOMEM;
 187
 188         r = ch341_control_in(dev, 0x95, 0x0706, 0, buffer, size);
 189         if (r < 0)
 190                 goto out;
 191
 192         spin_lock_irqsave(&priv->lock, flags);
 193         priv->line_status = (~(*buffer)) & CH341_BITS_MODEM_STAT;
 194         spin_unlock_irqrestore(&priv->lock, flags);
 195
 196 out:    kfree(buffer);
 197         return r;
 198 }
 199
 200 /* -------------------------------------------------------------------------- */
 201
 202 static int ch341_configure(struct usb_device *dev, struct ch341_private *priv)
 203 {
 204         const unsigned int size = 2;
 205         char *buffer;
 206         int r;
 207
 208         buffer = kmalloc(size, GFP_KERNEL);
 209         if (!buffer)
 210                 return -ENOMEM;
 211
 212         /* expect two bytes 0x27 0x00 */
 213         r = ch341_control_in(dev, 0x5f, 0, 0, buffer, size);
 214         if (r < 0)
 215                 goto out;
 216
 217         r = ch341_control_out(dev, 0xa1, 0, 0);
 218         if (r < 0)
 219                 goto out;
 220
 221         r = ch341_set_baudrate(dev, priv);
 222         if (r < 0)
 223                 goto out;
 224
 225         /* expect two bytes 0x56 0x00 */
 226         r = ch341_control_in(dev, 0x95, 0x2518, 0, buffer, size);
 227         if (r < 0)
 228                 goto out;
 229
 230         r = ch341_control_out(dev, 0x9a, 0x2518, 0x0050);
 231         if (r < 0)
 232                 goto out;
 233
 234         /* expect 0xff 0xee */
 235         r = ch341_get_status(dev, priv);
 236         if (r < 0)
 237                 goto out;
 238
 239         r = ch341_control_out(dev, 0xa1, 0x501f, 0xd90a);
 240         if (r < 0)
 241                 goto out;
 242
 243         r = ch341_set_baudrate(dev, priv);
 244         if (r < 0)
 245                 goto out;
 246
 247         r = ch341_set_handshake(dev, priv->line_control);
 248         if (r < 0)
 249                 goto out;
 250
 251         /* expect 0x9f 0xee */
 252         r = ch341_get_status(dev, priv);
 253
 254 out:    kfree(buffer);
 255         return r;
 256 }
 257
 258 static int ch341_port_probe(struct usb_serial_port *port)
 259 {
 260         struct ch341_private *priv;
 261         int r;
 262
 263         priv = kzalloc(sizeof(struct ch341_private), GFP_KERNEL);
 264         if (!priv)
 265                 return -ENOMEM;
 266
 267         spin_lock_init(&priv->lock);
 268         priv->baud_rate = DEFAULT_BAUD_RATE;
 269
 270         r = ch341_configure(port->serial->dev, priv);
 271         if (r < 0)
 272                 goto error;
 273
 274         usb_set_serial_port_data(port, priv);
 275         return 0;
 276
 277 error:  kfree(priv);
 278         return r;
 279 }
 280
 281 static int ch341_port_remove(struct usb_serial_port *port)
 282 {
 283         struct ch341_private *priv;
 284
 285         priv = usb_get_serial_port_data(port);
 286         kfree(priv);
 287
 288         return 0;
 289 }
 290
 291 static int ch341_carrier_raised(struct usb_serial_port *port)
 292 {
 293         struct ch341_private *priv = usb_get_serial_port_data(port);
 294         if (priv->line_status & CH341_BIT_DCD)
 295                 return 1;
 296         return 0;
 297 }
 298
 299 static void ch341_dtr_rts(struct usb_serial_port *port, int on)
 300 {
 301         struct ch341_private *priv = usb_get_serial_port_data(port);
 302         unsigned long flags;
 303
 304         /* drop DTR and RTS */
 305         spin_lock_irqsave(&priv->lock, flags);
 306         if (on)
 307                 priv->line_control |= CH341_BIT_RTS | CH341_BIT_DTR;
 308         else
 309                 priv->line_control &= ~(CH341_BIT_RTS | CH341_BIT_DTR);
 310         spin_unlock_irqrestore(&priv->lock, flags);
 311         ch341_set_handshake(port->serial->dev, priv->line_control);
 312 }
 313
 314 static void ch341_close(struct usb_serial_port *port)
 315 {
 316         usb_serial_generic_close(port);
 317         usb_kill_urb(port->interrupt_in_urb);
 318 }
 319
 320
 321 /* open this device, set default parameters */
 322 static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port)
 323 {
 324         struct usb_serial *serial = port->serial;
 325         struct ch341_private *priv = usb_get_serial_port_data(port);
 326         int r;
 327
 328         r = ch341_configure(serial->dev, priv);
 329         if (r)
 330                 return r;
 331
 332         if (tty)
 333                 ch341_set_termios(tty, port, NULL);
 334
 335         dev_dbg(&port->dev, "%s - submitting interrupt urb\n", __func__);
 336         r = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
 337         if (r) {
 338                 dev_err(&port->dev, "%s - failed to submit interrupt urb: %d\n",
 339                         __func__, r);
 340                 return r;
 341         }
 342
 343         r = usb_serial_generic_open(tty, port);
 344         if (r)
 345                 goto err_kill_interrupt_urb;
 346
 347         return 0;
 348
 349 err_kill_interrupt_urb:
 350         usb_kill_urb(port->interrupt_in_urb);
 351
 352         return r;
 353 }
 354
 355 /* Old_termios contains the original termios settings and
 356  * tty->termios contains the new setting to be used.
 357  */
 358 static void ch341_set_termios(struct tty_struct *tty,
 359                 struct usb_serial_port *port, struct ktermios *old_termios)
 360 {
 361         struct ch341_private *priv = usb_get_serial_port_data(port);
 362         unsigned baud_rate;
 363         unsigned long flags;
 364
 365         baud_rate = tty_get_baud_rate(tty);
 366
 367         if (baud_rate) {
 368                 priv->baud_rate = baud_rate;
 369                 ch341_set_baudrate(port->serial->dev, priv);
 370         }
 371
 372         /* Unimplemented:
 373          * (cflag & CSIZE) : data bits [5, 8]
 374          * (cflag & PARENB) : parity {NONE, EVEN, ODD}
 375          * (cflag & CSTOPB) : stop bits [1, 2]
 376          */
 377
 378         spin_lock_irqsave(&priv->lock, flags);
 379         if (C_BAUD(tty) == B0)
 380                 priv->line_control &= ~(CH341_BIT_DTR | CH341_BIT_RTS);
 381         else if (old_termios && (old_termios->c_cflag & CBAUD) == B0)
 382                 priv->line_control |= (CH341_BIT_DTR | CH341_BIT_RTS);
 383         spin_unlock_irqrestore(&priv->lock, flags);
 384
 385         ch341_set_handshake(port->serial->dev, priv->line_control);
 386 }
 387
 388 static void ch341_break_ctl(struct tty_struct *tty, int break_state)
 389 {
 390         const uint16_t ch341_break_reg =
 391                         ((uint16_t) CH341_REG_BREAK2 << 8) | CH341_REG_BREAK1;
 392         struct usb_serial_port *port = tty->driver_data;
 393         int r;
 394         uint16_t reg_contents;
 395         uint8_t *break_reg;
 396
 397         break_reg = kmalloc(2, GFP_KERNEL);
 398         if (!break_reg)
 399                 return;
 400
 401         r = ch341_control_in(port->serial->dev, CH341_REQ_READ_REG,
 402                         ch341_break_reg, 0, break_reg, 2);
 403         if (r < 0) {
 404                 dev_err(&port->dev, "%s - USB control read error (%d)\n",
 405                                 __func__, r);
 406                 goto out;
 407         }
 408         dev_dbg(&port->dev, "%s - initial ch341 break register contents - reg1: %x, reg2: %x\n",
 409                 __func__, break_reg[0], break_reg[1]);
 410         if (break_state != 0) {
 411                 dev_dbg(&port->dev, "%s - Enter break state requested\n", __func__);
 412                 break_reg[0] &= ~CH341_NBREAK_BITS_REG1;
 413                 break_reg[1] &= ~CH341_NBREAK_BITS_REG2;
 414         } else {
 415                 dev_dbg(&port->dev, "%s - Leave break state requested\n", __func__);
 416                 break_reg[0] |= CH341_NBREAK_BITS_REG1;
 417                 break_reg[1] |= CH341_NBREAK_BITS_REG2;
 418         }
 419         dev_dbg(&port->dev, "%s - New ch341 break register contents - reg1: %x, reg2: %x\n",
 420                 __func__, break_reg[0], break_reg[1]);
 421         reg_contents = get_unaligned_le16(break_reg);
 422         r = ch341_control_out(port->serial->dev, CH341_REQ_WRITE_REG,
 423                         ch341_break_reg, reg_contents);
 424         if (r < 0)
 425                 dev_err(&port->dev, "%s - USB control write error (%d)\n",
 426                                 __func__, r);
 427 out:
 428         kfree(break_reg);
 429 }
 430
 431 static int ch341_tiocmset(struct tty_struct *tty,
 432                           unsigned int set, unsigned int clear)
 433 {
 434         struct usb_serial_port *port = tty->driver_data;
 435         struct ch341_private *priv = usb_get_serial_port_data(port);
 436         unsigned long flags;
 437         u8 control;
 438
 439         spin_lock_irqsave(&priv->lock, flags);
 440         if (set & TIOCM_RTS)
 441                 priv->line_control |= CH341_BIT_RTS;
 442         if (set & TIOCM_DTR)
 443                 priv->line_control |= CH341_BIT_DTR;
 444         if (clear & TIOCM_RTS)
 445                 priv->line_control &= ~CH341_BIT_RTS;
 446         if (clear & TIOCM_DTR)
 447                 priv->line_control &= ~CH341_BIT_DTR;
 448         control = priv->line_control;
 449         spin_unlock_irqrestore(&priv->lock, flags);
 450
 451         return ch341_set_handshake(port->serial->dev, control);
 452 }
 453
 454 static void ch341_update_line_status(struct usb_serial_port *port,
 455                                         unsigned char *data, size_t len)
 456 {
 457         struct ch341_private *priv = usb_get_serial_port_data(port);
 458         struct tty_struct *tty;
 459         unsigned long flags;
 460         u8 status;
 461         u8 delta;
 462
 463         if (len < 4)
 464                 return;
 465
 466         status = ~data[2] & CH341_BITS_MODEM_STAT;
 467
 468         spin_lock_irqsave(&priv->lock, flags);
 469         delta = status ^ priv->line_status;
 470         priv->line_status = status;
 471         spin_unlock_irqrestore(&priv->lock, flags);
 472
 473         if (data[1] & CH341_MULT_STAT)
 474                 dev_dbg(&port->dev, "%s - multiple status change\n", __func__);
 475
 476         if (!delta)
 477                 return;
 478
 479         if (delta & CH341_BIT_CTS)
 480                 port->icount.cts++;
 481         if (delta & CH341_BIT_DSR)
 482                 port->icount.dsr++;
 483         if (delta & CH341_BIT_RI)
 484                 port->icount.rng++;
 485         if (delta & CH341_BIT_DCD) {
 486                 port->icount.dcd++;
 487                 tty = tty_port_tty_get(&port->port);
 488                 if (tty) {
 489                         usb_serial_handle_dcd_change(port, tty,
 490                                                 status & CH341_BIT_DCD);
 491                         tty_kref_put(tty);
 492                 }
 493         }
 494
 495         wake_up_interruptible(&port->port.delta_msr_wait);
 496 }
 497
 498 static void ch341_read_int_callback(struct urb *urb)
 499 {
 500         struct usb_serial_port *port = urb->context;
 501         unsigned char *data = urb->transfer_buffer;
 502         unsigned int len = urb->actual_length;
 503         int status;
 504
 505         switch (urb->status) {
 506         case 0:
 507                 /* success */
 508                 break;
 509         case -ECONNRESET:
 510         case -ENOENT:
 511         case -ESHUTDOWN:
 512                 /* this urb is terminated, clean up */
 513                 dev_dbg(&urb->dev->dev, "%s - urb shutting down: %d\n",
 514                         __func__, urb->status);
 515                 return;
 516         default:
 517                 dev_dbg(&urb->dev->dev, "%s - nonzero urb status: %d\n",
 518                         __func__, urb->status);
 519                 goto exit;
 520         }
 521
 522         usb_serial_debug_data(&port->dev, __func__, len, data);
 523         ch341_update_line_status(port, data, len);
 524 exit:
 525         status = usb_submit_urb(urb, GFP_ATOMIC);
 526         if (status) {
 527                 dev_err(&urb->dev->dev, "%s - usb_submit_urb failed: %d\n",
 528                         __func__, status);
 529         }
 530 }
 531
 532 static int ch341_tiocmget(struct tty_struct *tty)
 533 {
 534         struct usb_serial_port *port = tty->driver_data;
 535         struct ch341_private *priv = usb_get_serial_port_data(port);
 536         unsigned long flags;
 537         u8 mcr;
 538         u8 status;
 539         unsigned int result;
 540
 541         spin_lock_irqsave(&priv->lock, flags);
 542         mcr = priv->line_control;
 543         status = priv->line_status;
 544         spin_unlock_irqrestore(&priv->lock, flags);
 545
 546         result = ((mcr & CH341_BIT_DTR)         ? TIOCM_DTR : 0)
 547                   | ((mcr & CH341_BIT_RTS)      ? TIOCM_RTS : 0)
 548                   | ((status & CH341_BIT_CTS)   ? TIOCM_CTS : 0)
 549                   | ((status & CH341_BIT_DSR)   ? TIOCM_DSR : 0)
 550                   | ((status & CH341_BIT_RI)    ? TIOCM_RI  : 0)
 551                   | ((status & CH341_BIT_DCD)   ? TIOCM_CD  : 0);
 552
 553         dev_dbg(&port->dev, "%s - result = %x\n", __func__, result);
 554
 555         return result;
 556 }
 557
 558 static int ch341_reset_resume(struct usb_serial *serial)
 559 {
 560         struct usb_serial_port *port = serial->port[0];
 561         struct ch341_private *priv;
 562         int ret;
 563
 564         priv = usb_get_serial_port_data(port);
 565         if (!priv)
 566                 return 0;
 567
 568         /* reconfigure ch341 serial port after bus-reset */
 569         ch341_configure(serial->dev, priv);
 570
 571         if (tty_port_initialized(&port->port)) {
 572                 ret = usb_submit_urb(port->interrupt_in_urb, GFP_NOIO);
 573                 if (ret) {
 574                         dev_err(&port->dev, "failed to submit interrupt urb: %d\n",
 575                                 ret);
 576                         return ret;
 577                 }
 578         }
 579
 580         return usb_serial_generic_resume(serial);
 581 }
 582
 583 static struct usb_serial_driver ch341_device = {
 584         .driver = {
 585                 .owner  = THIS_MODULE,
 586                 .name   = "ch341-uart",
 587         },
 588         .id_table          = id_table,
 589         .num_ports         = 1,
 590         .open              = ch341_open,
 591         .dtr_rts           = ch341_dtr_rts,
 592         .carrier_raised    = ch341_carrier_raised,
 593         .close             = ch341_close,
 594         .set_termios       = ch341_set_termios,
 595         .break_ctl         = ch341_break_ctl,
 596         .tiocmget          = ch341_tiocmget,
 597         .tiocmset          = ch341_tiocmset,
 598         .tiocmiwait        = usb_serial_generic_tiocmiwait,
 599         .read_int_callback = ch341_read_int_callback,
 600         .port_probe        = ch341_port_probe,
 601         .port_remove       = ch341_port_remove,
 602         .reset_resume      = ch341_reset_resume,
 603 };
 604
 605 static struct usb_serial_driver * const serial_drivers[] = {
 606         &ch341_device, NULL
 607 };
 608
 609 module_usb_serial_driver(serial_drivers, id_table);
 610
 611 MODULE_LICENSE("GPL");