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