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 int debug; 74 75 static const struct usb_device_id id_table[] = { 76 { USB_DEVICE(0x4348, 0x5523) }, 77 { USB_DEVICE(0x1a86, 0x7523) }, 78 { USB_DEVICE(0x1a86, 0x5523) }, 79 { }, 80 }; 81 MODULE_DEVICE_TABLE(usb, id_table); 82 83 struct ch341_private { 84 spinlock_t lock; /* access lock */ 85 wait_queue_head_t delta_msr_wait; /* wait queue for modem status */ 86 unsigned baud_rate; /* set baud rate */ 87 u8 line_control; /* set line control value RTS/DTR */ 88 u8 line_status; /* active status of modem control inputs */ 89 u8 multi_status_change; /* status changed multiple since last call */ 90 }; 91 92 static int ch341_control_out(struct usb_device *dev, u8 request, 93 u16 value, u16 index) 94 { 95 int r; 96 dbg("ch341_control_out(%02x,%02x,%04x,%04x)", USB_DIR_OUT|0x40, 97 (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); 102 103 return r; 104 } 105 106 static int ch341_control_in(struct usb_device *dev, 107 u8 request, u16 value, u16 index, 108 char *buf, unsigned bufsize) 109 { 110 int r; 111 dbg("ch341_control_in(%02x,%02x,%04x,%04x,%p,%u)", USB_DIR_IN|0x40, 112 (int)request, (int)value, (int)index, buf, (int)bufsize); 113 114 r = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), request, 115 USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN, 116 value, index, buf, bufsize, DEFAULT_TIMEOUT); 117 return r; 118 } 119 120 static int ch341_set_baudrate(struct usb_device *dev, 121 struct ch341_private *priv) 122 { 123 short a, b; 124 int r; 125 unsigned long factor; 126 short divisor; 127 128 dbg("ch341_set_baudrate(%d)", priv->baud_rate); 129 130 if (!priv->baud_rate) 131 return -EINVAL; 132 factor = (CH341_BAUDBASE_FACTOR / priv->baud_rate); 133 divisor = CH341_BAUDBASE_DIVMAX; 134 135 while ((factor > 0xfff0) && divisor) { 136 factor >>= 3; 137 divisor--; 138 } 139 140 if (factor > 0xfff0) 141 return -EINVAL; 142 143 factor = 0x10000 - factor; 144 a = (factor & 0xff00) | divisor; 145 b = factor & 0xff; 146 147 r = ch341_control_out(dev, 0x9a, 0x1312, a); 148 if (!r) 149 r = ch341_control_out(dev, 0x9a, 0x0f2c, b); 150 151 return r; 152 } 153 154 static int ch341_set_handshake(struct usb_device *dev, u8 control) 155 { 156 dbg("ch341_set_handshake(0x%02x)", control); 157 return ch341_control_out(dev, 0xa4, ~control, 0); 158 } 159 160 static int ch341_get_status(struct usb_device *dev, struct ch341_private *priv) 161 { 162 char *buffer; 163 int r; 164 const unsigned size = 8; 165 unsigned long flags; 166 167 dbg("ch341_get_status()"); 168 169 buffer = kmalloc(size, GFP_KERNEL); 170 if (!buffer) 171 return -ENOMEM; 172 173 r = ch341_control_in(dev, 0x95, 0x0706, 0, buffer, size); 174 if (r < 0) 175 goto out; 176 177 /* setup the private status if available */ 178 if (r == 2) { 179 r = 0; 180 spin_lock_irqsave(&priv->lock, flags); 181 priv->line_status = (~(*buffer)) & CH341_BITS_MODEM_STAT; 182 priv->multi_status_change = 0; 183 spin_unlock_irqrestore(&priv->lock, flags); 184 } else 185 r = -EPROTO; 186 187 out: kfree(buffer); 188 return r; 189 } 190 191 /* -------------------------------------------------------------------------- */ 192 193 static int ch341_configure(struct usb_device *dev, struct ch341_private *priv) 194 { 195 char *buffer; 196 int r; 197 const unsigned size = 8; 198 199 dbg("ch341_configure()"); 200 201 buffer = kmalloc(size, GFP_KERNEL); 202 if (!buffer) 203 return -ENOMEM; 204 205 /* expect two bytes 0x27 0x00 */ 206 r = ch341_control_in(dev, 0x5f, 0, 0, buffer, size); 207 if (r < 0) 208 goto out; 209 210 r = ch341_control_out(dev, 0xa1, 0, 0); 211 if (r < 0) 212 goto out; 213 214 r = ch341_set_baudrate(dev, priv); 215 if (r < 0) 216 goto out; 217 218 /* expect two bytes 0x56 0x00 */ 219 r = ch341_control_in(dev, 0x95, 0x2518, 0, buffer, size); 220 if (r < 0) 221 goto out; 222 223 r = ch341_control_out(dev, 0x9a, 0x2518, 0x0050); 224 if (r < 0) 225 goto out; 226 227 /* expect 0xff 0xee */ 228 r = ch341_get_status(dev, priv); 229 if (r < 0) 230 goto out; 231 232 r = ch341_control_out(dev, 0xa1, 0x501f, 0xd90a); 233 if (r < 0) 234 goto out; 235 236 r = ch341_set_baudrate(dev, priv); 237 if (r < 0) 238 goto out; 239 240 r = ch341_set_handshake(dev, priv->line_control); 241 if (r < 0) 242 goto out; 243 244 /* expect 0x9f 0xee */ 245 r = ch341_get_status(dev, priv); 246 247 out: kfree(buffer); 248 return r; 249 } 250 251 /* allocate private data */ 252 static int ch341_attach(struct usb_serial *serial) 253 { 254 struct ch341_private *priv; 255 int r; 256 257 dbg("ch341_attach()"); 258 259 /* private data */ 260 priv = kzalloc(sizeof(struct ch341_private), GFP_KERNEL); 261 if (!priv) 262 return -ENOMEM; 263 264 spin_lock_init(&priv->lock); 265 init_waitqueue_head(&priv->delta_msr_wait); 266 priv->baud_rate = DEFAULT_BAUD_RATE; 267 priv->line_control = CH341_BIT_RTS | CH341_BIT_DTR; 268 269 r = ch341_configure(serial->dev, priv); 270 if (r < 0) 271 goto error; 272 273 usb_set_serial_port_data(serial->port[0], priv); 274 return 0; 275 276 error: kfree(priv); 277 return r; 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 dbg("%s - port %d", __func__, port->number); 294 /* drop DTR and RTS */ 295 spin_lock_irqsave(&priv->lock, flags); 296 if (on) 297 priv->line_control |= CH341_BIT_RTS | CH341_BIT_DTR; 298 else 299 priv->line_control &= ~(CH341_BIT_RTS | CH341_BIT_DTR); 300 spin_unlock_irqrestore(&priv->lock, flags); 301 ch341_set_handshake(port->serial->dev, priv->line_control); 302 wake_up_interruptible(&priv->delta_msr_wait); 303 } 304 305 static void ch341_close(struct usb_serial_port *port) 306 { 307 dbg("%s - port %d", __func__, port->number); 308 309 usb_serial_generic_close(port); 310 usb_kill_urb(port->interrupt_in_urb); 311 } 312 313 314 /* open this device, set default parameters */ 315 static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port) 316 { 317 struct usb_serial *serial = port->serial; 318 struct ch341_private *priv = usb_get_serial_port_data(serial->port[0]); 319 int r; 320 321 dbg("ch341_open()"); 322 323 priv->baud_rate = DEFAULT_BAUD_RATE; 324 325 r = ch341_configure(serial->dev, priv); 326 if (r) 327 goto out; 328 329 r = ch341_set_handshake(serial->dev, priv->line_control); 330 if (r) 331 goto out; 332 333 r = ch341_set_baudrate(serial->dev, priv); 334 if (r) 335 goto out; 336 337 dbg("%s - submitting interrupt urb", __func__); 338 port->interrupt_in_urb->dev = serial->dev; 339 r = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL); 340 if (r) { 341 dev_err(&port->dev, "%s - failed submitting interrupt urb," 342 " error %d\n", __func__, r); 343 ch341_close(port); 344 return -EPROTO; 345 } 346 347 r = usb_serial_generic_open(tty, port); 348 349 out: 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 dbg("ch341_set_termios()"); 363 364 baud_rate = tty_get_baud_rate(tty); 365 366 priv->baud_rate = baud_rate; 367 368 if (baud_rate) { 369 spin_lock_irqsave(&priv->lock, flags); 370 priv->line_control |= (CH341_BIT_DTR | CH341_BIT_RTS); 371 spin_unlock_irqrestore(&priv->lock, flags); 372 ch341_set_baudrate(port->serial->dev, priv); 373 } else { 374 spin_lock_irqsave(&priv->lock, flags); 375 priv->line_control &= ~(CH341_BIT_DTR | CH341_BIT_RTS); 376 spin_unlock_irqrestore(&priv->lock, flags); 377 } 378 379 ch341_set_handshake(port->serial->dev, priv->line_control); 380 381 /* Unimplemented: 382 * (cflag & CSIZE) : data bits [5, 8] 383 * (cflag & PARENB) : parity {NONE, EVEN, ODD} 384 * (cflag & CSTOPB) : stop bits [1, 2] 385 */ 386 } 387 388 static void ch341_break_ctl(struct tty_struct *tty, int break_state) 389 { 390 const uint16_t ch341_break_reg = 391 CH341_REG_BREAK1 | ((uint16_t) CH341_REG_BREAK2 << 8); 392 struct usb_serial_port *port = tty->driver_data; 393 int r; 394 uint16_t reg_contents; 395 uint8_t *break_reg; 396 397 dbg("%s()", __func__); 398 399 break_reg = kmalloc(2, GFP_KERNEL); 400 if (!break_reg) { 401 dev_err(&port->dev, "%s - kmalloc failed\n", __func__); 402 return; 403 } 404 405 r = ch341_control_in(port->serial->dev, CH341_REQ_READ_REG, 406 ch341_break_reg, 0, break_reg, 2); 407 if (r < 0) { 408 dev_err(&port->dev, "%s - USB control read error (%d)\n", 409 __func__, r); 410 goto out; 411 } 412 dbg("%s - initial ch341 break register contents - reg1: %x, reg2: %x", 413 __func__, break_reg[0], break_reg[1]); 414 if (break_state != 0) { 415 dbg("%s - Enter break state requested", __func__); 416 break_reg[0] &= ~CH341_NBREAK_BITS_REG1; 417 break_reg[1] &= ~CH341_NBREAK_BITS_REG2; 418 } else { 419 dbg("%s - Leave break state requested", __func__); 420 break_reg[0] |= CH341_NBREAK_BITS_REG1; 421 break_reg[1] |= CH341_NBREAK_BITS_REG2; 422 } 423 dbg("%s - New ch341 break register contents - reg1: %x, reg2: %x", 424 __func__, break_reg[0], break_reg[1]); 425 reg_contents = get_unaligned_le16(break_reg); 426 r = ch341_control_out(port->serial->dev, CH341_REQ_WRITE_REG, 427 ch341_break_reg, reg_contents); 428 if (r < 0) 429 dev_err(&port->dev, "%s - USB control write error (%d)\n", 430 __func__, r); 431 out: 432 kfree(break_reg); 433 } 434 435 static int ch341_tiocmset(struct tty_struct *tty, 436 unsigned int set, unsigned int clear) 437 { 438 struct usb_serial_port *port = tty->driver_data; 439 struct ch341_private *priv = usb_get_serial_port_data(port); 440 unsigned long flags; 441 u8 control; 442 443 spin_lock_irqsave(&priv->lock, flags); 444 if (set & TIOCM_RTS) 445 priv->line_control |= CH341_BIT_RTS; 446 if (set & TIOCM_DTR) 447 priv->line_control |= CH341_BIT_DTR; 448 if (clear & TIOCM_RTS) 449 priv->line_control &= ~CH341_BIT_RTS; 450 if (clear & TIOCM_DTR) 451 priv->line_control &= ~CH341_BIT_DTR; 452 control = priv->line_control; 453 spin_unlock_irqrestore(&priv->lock, flags); 454 455 return ch341_set_handshake(port->serial->dev, control); 456 } 457 458 static void ch341_read_int_callback(struct urb *urb) 459 { 460 struct usb_serial_port *port = (struct usb_serial_port *) urb->context; 461 unsigned char *data = urb->transfer_buffer; 462 unsigned int actual_length = urb->actual_length; 463 int status; 464 465 dbg("%s (%d)", __func__, port->number); 466 467 switch (urb->status) { 468 case 0: 469 /* success */ 470 break; 471 case -ECONNRESET: 472 case -ENOENT: 473 case -ESHUTDOWN: 474 /* this urb is terminated, clean up */ 475 dbg("%s - urb shutting down with status: %d", __func__, 476 urb->status); 477 return; 478 default: 479 dbg("%s - nonzero urb status received: %d", __func__, 480 urb->status); 481 goto exit; 482 } 483 484 usb_serial_debug_data(debug, &port->dev, __func__, 485 urb->actual_length, urb->transfer_buffer); 486 487 if (actual_length >= 4) { 488 struct ch341_private *priv = usb_get_serial_port_data(port); 489 unsigned long flags; 490 u8 prev_line_status = priv->line_status; 491 492 spin_lock_irqsave(&priv->lock, flags); 493 priv->line_status = (~(data[2])) & CH341_BITS_MODEM_STAT; 494 if ((data[1] & CH341_MULT_STAT)) 495 priv->multi_status_change = 1; 496 spin_unlock_irqrestore(&priv->lock, flags); 497 498 if ((priv->line_status ^ prev_line_status) & CH341_BIT_DCD) { 499 struct tty_struct *tty = tty_port_tty_get(&port->port); 500 if (tty) 501 usb_serial_handle_dcd_change(port, tty, 502 priv->line_status & CH341_BIT_DCD); 503 tty_kref_put(tty); 504 } 505 506 wake_up_interruptible(&priv->delta_msr_wait); 507 } 508 509 exit: 510 status = usb_submit_urb(urb, GFP_ATOMIC); 511 if (status) 512 dev_err(&urb->dev->dev, 513 "%s - usb_submit_urb failed with result %d\n", 514 __func__, status); 515 } 516 517 static int wait_modem_info(struct usb_serial_port *port, unsigned int arg) 518 { 519 struct ch341_private *priv = usb_get_serial_port_data(port); 520 unsigned long flags; 521 u8 prevstatus; 522 u8 status; 523 u8 changed; 524 u8 multi_change = 0; 525 526 spin_lock_irqsave(&priv->lock, flags); 527 prevstatus = priv->line_status; 528 priv->multi_status_change = 0; 529 spin_unlock_irqrestore(&priv->lock, flags); 530 531 while (!multi_change) { 532 interruptible_sleep_on(&priv->delta_msr_wait); 533 /* see if a signal did it */ 534 if (signal_pending(current)) 535 return -ERESTARTSYS; 536 537 spin_lock_irqsave(&priv->lock, flags); 538 status = priv->line_status; 539 multi_change = priv->multi_status_change; 540 spin_unlock_irqrestore(&priv->lock, flags); 541 542 changed = prevstatus ^ status; 543 544 if (((arg & TIOCM_RNG) && (changed & CH341_BIT_RI)) || 545 ((arg & TIOCM_DSR) && (changed & CH341_BIT_DSR)) || 546 ((arg & TIOCM_CD) && (changed & CH341_BIT_DCD)) || 547 ((arg & TIOCM_CTS) && (changed & CH341_BIT_CTS))) { 548 return 0; 549 } 550 prevstatus = status; 551 } 552 553 return 0; 554 } 555 556 static int ch341_ioctl(struct tty_struct *tty, 557 unsigned int cmd, unsigned long arg) 558 { 559 struct usb_serial_port *port = tty->driver_data; 560 dbg("%s (%d) cmd = 0x%04x", __func__, port->number, cmd); 561 562 switch (cmd) { 563 case TIOCMIWAIT: 564 dbg("%s (%d) TIOCMIWAIT", __func__, port->number); 565 return wait_modem_info(port, arg); 566 567 default: 568 dbg("%s not supported = 0x%04x", __func__, cmd); 569 break; 570 } 571 572 return -ENOIOCTLCMD; 573 } 574 575 static int ch341_tiocmget(struct tty_struct *tty) 576 { 577 struct usb_serial_port *port = tty->driver_data; 578 struct ch341_private *priv = usb_get_serial_port_data(port); 579 unsigned long flags; 580 u8 mcr; 581 u8 status; 582 unsigned int result; 583 584 dbg("%s (%d)", __func__, port->number); 585 586 spin_lock_irqsave(&priv->lock, flags); 587 mcr = priv->line_control; 588 status = priv->line_status; 589 spin_unlock_irqrestore(&priv->lock, flags); 590 591 result = ((mcr & CH341_BIT_DTR) ? TIOCM_DTR : 0) 592 | ((mcr & CH341_BIT_RTS) ? TIOCM_RTS : 0) 593 | ((status & CH341_BIT_CTS) ? TIOCM_CTS : 0) 594 | ((status & CH341_BIT_DSR) ? TIOCM_DSR : 0) 595 | ((status & CH341_BIT_RI) ? TIOCM_RI : 0) 596 | ((status & CH341_BIT_DCD) ? TIOCM_CD : 0); 597 598 dbg("%s - result = %x", __func__, result); 599 600 return result; 601 } 602 603 604 static int ch341_reset_resume(struct usb_interface *intf) 605 { 606 struct usb_device *dev = interface_to_usbdev(intf); 607 struct usb_serial *serial = NULL; 608 struct ch341_private *priv; 609 610 serial = usb_get_intfdata(intf); 611 priv = usb_get_serial_port_data(serial->port[0]); 612 613 /*reconfigure ch341 serial port after bus-reset*/ 614 ch341_configure(dev, priv); 615 616 usb_serial_resume(intf); 617 618 return 0; 619 } 620 621 static struct usb_driver ch341_driver = { 622 .name = "ch341", 623 .probe = usb_serial_probe, 624 .disconnect = usb_serial_disconnect, 625 .suspend = usb_serial_suspend, 626 .resume = usb_serial_resume, 627 .reset_resume = ch341_reset_resume, 628 .id_table = id_table, 629 .no_dynamic_id = 1, 630 .supports_autosuspend = 1, 631 }; 632 633 static struct usb_serial_driver ch341_device = { 634 .driver = { 635 .owner = THIS_MODULE, 636 .name = "ch341-uart", 637 }, 638 .id_table = id_table, 639 .usb_driver = &ch341_driver, 640 .num_ports = 1, 641 .open = ch341_open, 642 .dtr_rts = ch341_dtr_rts, 643 .carrier_raised = ch341_carrier_raised, 644 .close = ch341_close, 645 .ioctl = ch341_ioctl, 646 .set_termios = ch341_set_termios, 647 .break_ctl = ch341_break_ctl, 648 .tiocmget = ch341_tiocmget, 649 .tiocmset = ch341_tiocmset, 650 .read_int_callback = ch341_read_int_callback, 651 .attach = ch341_attach, 652 }; 653 654 static int __init ch341_init(void) 655 { 656 int retval; 657 658 retval = usb_serial_register(&ch341_device); 659 if (retval) 660 return retval; 661 retval = usb_register(&ch341_driver); 662 if (retval) 663 usb_serial_deregister(&ch341_device); 664 return retval; 665 } 666 667 static void __exit ch341_exit(void) 668 { 669 usb_deregister(&ch341_driver); 670 usb_serial_deregister(&ch341_device); 671 } 672 673 module_init(ch341_init); 674 module_exit(ch341_exit); 675 MODULE_LICENSE("GPL"); 676 677 module_param(debug, bool, S_IRUGO | S_IWUSR); 678 MODULE_PARM_DESC(debug, "Debug enabled or not"); 679 680 /* EOF ch341.c */ 681