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