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 /* allocate private data */
 246 static int ch341_attach(struct usb_serial *serial)
 247 {
 248         struct ch341_private *priv;
 249         int r;
 250
 251         /* private data */
 252         priv = kzalloc(sizeof(struct ch341_private), GFP_KERNEL);
 253         if (!priv)
 254                 return -ENOMEM;
 255
 256         spin_lock_init(&priv->lock);
 257         init_waitqueue_head(&priv->delta_msr_wait);
 258         priv->baud_rate = DEFAULT_BAUD_RATE;
 259         priv->line_control = CH341_BIT_RTS | CH341_BIT_DTR;
 260
 261         r = ch341_configure(serial->dev, priv);
 262         if (r < 0)
 263                 goto error;
 264
 265         usb_set_serial_port_data(serial->port[0], priv);
 266         return 0;
 267
 268 error:  kfree(priv);
 269         return r;
 270 }
 271
 272 static int ch341_carrier_raised(struct usb_serial_port *port)
 273 {
 274         struct ch341_private *priv = usb_get_serial_port_data(port);
 275         if (priv->line_status & CH341_BIT_DCD)
 276                 return 1;
 277         return 0;
 278 }
 279
 280 static void ch341_dtr_rts(struct usb_serial_port *port, int on)
 281 {
 282         struct ch341_private *priv = usb_get_serial_port_data(port);
 283         unsigned long flags;
 284
 285         /* drop DTR and RTS */
 286         spin_lock_irqsave(&priv->lock, flags);
 287         if (on)
 288                 priv->line_control |= CH341_BIT_RTS | CH341_BIT_DTR;
 289         else
 290                 priv->line_control &= ~(CH341_BIT_RTS | CH341_BIT_DTR);
 291         spin_unlock_irqrestore(&priv->lock, flags);
 292         ch341_set_handshake(port->serial->dev, priv->line_control);
 293         wake_up_interruptible(&priv->delta_msr_wait);
 294 }
 295
 296 static void ch341_close(struct usb_serial_port *port)
 297 {
 298         usb_serial_generic_close(port);
 299         usb_kill_urb(port->interrupt_in_urb);
 300 }
 301
 302
 303 /* open this device, set default parameters */
 304 static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port)
 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         priv->baud_rate = DEFAULT_BAUD_RATE;
 311
 312         r = ch341_configure(serial->dev, priv);
 313         if (r)
 314                 goto out;
 315
 316         r = ch341_set_handshake(serial->dev, priv->line_control);
 317         if (r)
 318                 goto out;
 319
 320         r = ch341_set_baudrate(serial->dev, priv);
 321         if (r)
 322                 goto out;
 323
 324         dev_dbg(&port->dev, "%s - submitting interrupt urb", __func__);
 325         r = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
 326         if (r) {
 327                 dev_err(&port->dev, "%s - failed submitting interrupt urb,"
 328                         " error %d\n", __func__, r);
 329                 ch341_close(port);
 330                 goto out;
 331         }
 332
 333         r = usb_serial_generic_open(tty, port);
 334
 335 out:    return r;
 336 }
 337
 338 /* Old_termios contains the original termios settings and
 339  * tty->termios contains the new setting to be used.
 340  */
 341 static void ch341_set_termios(struct tty_struct *tty,
 342                 struct usb_serial_port *port, struct ktermios *old_termios)
 343 {
 344         struct ch341_private *priv = usb_get_serial_port_data(port);
 345         unsigned baud_rate;
 346         unsigned long flags;
 347
 348         baud_rate = tty_get_baud_rate(tty);
 349
 350         priv->baud_rate = baud_rate;
 351
 352         if (baud_rate) {
 353                 spin_lock_irqsave(&priv->lock, flags);
 354                 priv->line_control |= (CH341_BIT_DTR | CH341_BIT_RTS);
 355                 spin_unlock_irqrestore(&priv->lock, flags);
 356                 ch341_set_baudrate(port->serial->dev, priv);
 357         } else {
 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         }
 362
 363         ch341_set_handshake(port->serial->dev, priv->line_control);
 364
 365         /* Unimplemented:
 366          * (cflag & CSIZE) : data bits [5, 8]
 367          * (cflag & PARENB) : parity {NONE, EVEN, ODD}
 368          * (cflag & CSTOPB) : stop bits [1, 2]
 369          */
 370 }
 371
 372 static void ch341_break_ctl(struct tty_struct *tty, int break_state)
 373 {
 374         const uint16_t ch341_break_reg =
 375                 CH341_REG_BREAK1 | ((uint16_t) CH341_REG_BREAK2 << 8);
 376         struct usb_serial_port *port = tty->driver_data;
 377         int r;
 378         uint16_t reg_contents;
 379         uint8_t *break_reg;
 380
 381         break_reg = kmalloc(2, GFP_KERNEL);
 382         if (!break_reg) {
 383                 dev_err(&port->dev, "%s - kmalloc failed\n", __func__);
 384                 return;
 385         }
 386
 387         r = ch341_control_in(port->serial->dev, CH341_REQ_READ_REG,
 388                         ch341_break_reg, 0, break_reg, 2);
 389         if (r < 0) {
 390                 dev_err(&port->dev, "%s - USB control read error (%d)\n",
 391                                 __func__, r);
 392                 goto out;
 393         }
 394         dev_dbg(&port->dev, "%s - initial ch341 break register contents - reg1: %x, reg2: %x\n",
 395                 __func__, break_reg[0], break_reg[1]);
 396         if (break_state != 0) {
 397                 dev_dbg(&port->dev, "%s - Enter break state requested\n", __func__);
 398                 break_reg[0] &= ~CH341_NBREAK_BITS_REG1;
 399                 break_reg[1] &= ~CH341_NBREAK_BITS_REG2;
 400         } else {
 401                 dev_dbg(&port->dev, "%s - Leave break state requested\n", __func__);
 402                 break_reg[0] |= CH341_NBREAK_BITS_REG1;
 403                 break_reg[1] |= CH341_NBREAK_BITS_REG2;
 404         }
 405         dev_dbg(&port->dev, "%s - New ch341 break register contents - reg1: %x, reg2: %x\n",
 406                 __func__, break_reg[0], break_reg[1]);
 407         reg_contents = get_unaligned_le16(break_reg);
 408         r = ch341_control_out(port->serial->dev, CH341_REQ_WRITE_REG,
 409                         ch341_break_reg, reg_contents);
 410         if (r < 0)
 411                 dev_err(&port->dev, "%s - USB control write error (%d)\n",
 412                                 __func__, r);
 413 out:
 414         kfree(break_reg);
 415 }
 416
 417 static int ch341_tiocmset(struct tty_struct *tty,
 418                           unsigned int set, unsigned int clear)
 419 {
 420         struct usb_serial_port *port = tty->driver_data;
 421         struct ch341_private *priv = usb_get_serial_port_data(port);
 422         unsigned long flags;
 423         u8 control;
 424
 425         spin_lock_irqsave(&priv->lock, flags);
 426         if (set & TIOCM_RTS)
 427                 priv->line_control |= CH341_BIT_RTS;
 428         if (set & TIOCM_DTR)
 429                 priv->line_control |= CH341_BIT_DTR;
 430         if (clear & TIOCM_RTS)
 431                 priv->line_control &= ~CH341_BIT_RTS;
 432         if (clear & TIOCM_DTR)
 433                 priv->line_control &= ~CH341_BIT_DTR;
 434         control = priv->line_control;
 435         spin_unlock_irqrestore(&priv->lock, flags);
 436
 437         return ch341_set_handshake(port->serial->dev, control);
 438 }
 439
 440 static void ch341_read_int_callback(struct urb *urb)
 441 {
 442         struct usb_serial_port *port = (struct usb_serial_port *) urb->context;
 443         unsigned char *data = urb->transfer_buffer;
 444         unsigned int actual_length = urb->actual_length;
 445         int status;
 446
 447         switch (urb->status) {
 448         case 0:
 449                 /* success */
 450                 break;
 451         case -ECONNRESET:
 452         case -ENOENT:
 453         case -ESHUTDOWN:
 454                 /* this urb is terminated, clean up */
 455                 dev_dbg(&urb->dev->dev, "%s - urb shutting down with status: %d\n",
 456                         __func__, urb->status);
 457                 return;
 458         default:
 459                 dev_dbg(&urb->dev->dev, "%s - nonzero urb status received: %d\n",
 460                         __func__, urb->status);
 461                 goto exit;
 462         }
 463
 464         usb_serial_debug_data(&port->dev, __func__,
 465                               urb->actual_length, urb->transfer_buffer);
 466
 467         if (actual_length >= 4) {
 468                 struct ch341_private *priv = usb_get_serial_port_data(port);
 469                 unsigned long flags;
 470                 u8 prev_line_status = priv->line_status;
 471
 472                 spin_lock_irqsave(&priv->lock, flags);
 473                 priv->line_status = (~(data[2])) & CH341_BITS_MODEM_STAT;
 474                 if ((data[1] & CH341_MULT_STAT))
 475                         priv->multi_status_change = 1;
 476                 spin_unlock_irqrestore(&priv->lock, flags);
 477
 478                 if ((priv->line_status ^ prev_line_status) & CH341_BIT_DCD) {
 479                         struct tty_struct *tty = tty_port_tty_get(&port->port);
 480                         if (tty)
 481                                 usb_serial_handle_dcd_change(port, tty,
 482                                             priv->line_status & CH341_BIT_DCD);
 483                         tty_kref_put(tty);
 484                 }
 485
 486                 wake_up_interruptible(&priv->delta_msr_wait);
 487         }
 488
 489 exit:
 490         status = usb_submit_urb(urb, GFP_ATOMIC);
 491         if (status)
 492                 dev_err(&urb->dev->dev,
 493                         "%s - usb_submit_urb failed with result %d\n",
 494                         __func__, status);
 495 }
 496
 497 static int wait_modem_info(struct usb_serial_port *port, unsigned int arg)
 498 {
 499         struct ch341_private *priv = usb_get_serial_port_data(port);
 500         unsigned long flags;
 501         u8 prevstatus;
 502         u8 status;
 503         u8 changed;
 504         u8 multi_change = 0;
 505
 506         spin_lock_irqsave(&priv->lock, flags);
 507         prevstatus = priv->line_status;
 508         priv->multi_status_change = 0;
 509         spin_unlock_irqrestore(&priv->lock, flags);
 510
 511         while (!multi_change) {
 512                 interruptible_sleep_on(&priv->delta_msr_wait);
 513                 /* see if a signal did it */
 514                 if (signal_pending(current))
 515                         return -ERESTARTSYS;
 516
 517                 spin_lock_irqsave(&priv->lock, flags);
 518                 status = priv->line_status;
 519                 multi_change = priv->multi_status_change;
 520                 spin_unlock_irqrestore(&priv->lock, flags);
 521
 522                 changed = prevstatus ^ status;
 523
 524                 if (((arg & TIOCM_RNG) && (changed & CH341_BIT_RI)) ||
 525                     ((arg & TIOCM_DSR) && (changed & CH341_BIT_DSR)) ||
 526                     ((arg & TIOCM_CD)  && (changed & CH341_BIT_DCD)) ||
 527                     ((arg & TIOCM_CTS) && (changed & CH341_BIT_CTS))) {
 528                         return 0;
 529                 }
 530                 prevstatus = status;
 531         }
 532
 533         return 0;
 534 }
 535
 536 static int ch341_ioctl(struct tty_struct *tty,
 537                         unsigned int cmd, unsigned long arg)
 538 {
 539         struct usb_serial_port *port = tty->driver_data;
 540
 541         dev_dbg(&port->dev, "%s (%d) cmd = 0x%04x\n", __func__, port->number, cmd);
 542
 543         switch (cmd) {
 544         case TIOCMIWAIT:
 545                 dev_dbg(&port->dev, "%s (%d) TIOCMIWAIT\n", __func__,  port->number);
 546                 return wait_modem_info(port, arg);
 547
 548         default:
 549                 dev_dbg(&port->dev, "%s not supported = 0x%04x\n", __func__, cmd);
 550                 break;
 551         }
 552
 553         return -ENOIOCTLCMD;
 554 }
 555
 556 static int ch341_tiocmget(struct tty_struct *tty)
 557 {
 558         struct usb_serial_port *port = tty->driver_data;
 559         struct ch341_private *priv = usb_get_serial_port_data(port);
 560         unsigned long flags;
 561         u8 mcr;
 562         u8 status;
 563         unsigned int result;
 564
 565         spin_lock_irqsave(&priv->lock, flags);
 566         mcr = priv->line_control;
 567         status = priv->line_status;
 568         spin_unlock_irqrestore(&priv->lock, flags);
 569
 570         result = ((mcr & CH341_BIT_DTR)         ? TIOCM_DTR : 0)
 571                   | ((mcr & CH341_BIT_RTS)      ? TIOCM_RTS : 0)
 572                   | ((status & CH341_BIT_CTS)   ? TIOCM_CTS : 0)
 573                   | ((status & CH341_BIT_DSR)   ? TIOCM_DSR : 0)
 574                   | ((status & CH341_BIT_RI)    ? TIOCM_RI  : 0)
 575                   | ((status & CH341_BIT_DCD)   ? TIOCM_CD  : 0);
 576
 577         dev_dbg(&port->dev, "%s - result = %x\n", __func__, result);
 578
 579         return result;
 580 }
 581
 582 static int ch341_reset_resume(struct usb_serial *serial)
 583 {
 584         struct ch341_private *priv;
 585
 586         priv = usb_get_serial_port_data(serial->port[0]);
 587
 588         /* reconfigure ch341 serial port after bus-reset */
 589         ch341_configure(serial->dev, priv);
 590
 591         return 0;
 592 }
 593
 594 static struct usb_serial_driver ch341_device = {
 595         .driver = {
 596                 .owner  = THIS_MODULE,
 597                 .name   = "ch341-uart",
 598         },
 599         .id_table          = id_table,
 600         .num_ports         = 1,
 601         .open              = ch341_open,
 602         .dtr_rts           = ch341_dtr_rts,
 603         .carrier_raised    = ch341_carrier_raised,
 604         .close             = ch341_close,
 605         .ioctl             = ch341_ioctl,
 606         .set_termios       = ch341_set_termios,
 607         .break_ctl         = ch341_break_ctl,
 608         .tiocmget          = ch341_tiocmget,
 609         .tiocmset          = ch341_tiocmset,
 610         .read_int_callback = ch341_read_int_callback,
 611         .attach            = ch341_attach,
 612         .reset_resume      = ch341_reset_resume,
 613 };
 614
 615 static struct usb_serial_driver * const serial_drivers[] = {
 616         &ch341_device, NULL
 617 };
 618
 619 module_usb_serial_driver(serial_drivers, id_table);
 620
 621 MODULE_LICENSE("GPL");