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/usb.h> 23 #include <linux/usb/serial.h> 24 #include <linux/serial.h> 25 26 #define DEFAULT_BAUD_RATE 9600 27 #define DEFAULT_TIMEOUT 1000 28 29 /* flags for IO-Bits */ 30 #define CH341_BIT_RTS (1 << 6) 31 #define CH341_BIT_DTR (1 << 5) 32 33 /******************************/ 34 /* interrupt pipe definitions */ 35 /******************************/ 36 /* always 4 interrupt bytes */ 37 /* first irq byte normally 0x08 */ 38 /* second irq byte base 0x7d + below */ 39 /* third irq byte base 0x94 + below */ 40 /* fourth irq byte normally 0xee */ 41 42 /* second interrupt byte */ 43 #define CH341_MULT_STAT 0x04 /* multiple status since last interrupt event */ 44 45 /* status returned in third interrupt answer byte, inverted in data 46 from irq */ 47 #define CH341_BIT_CTS 0x01 48 #define CH341_BIT_DSR 0x02 49 #define CH341_BIT_RI 0x04 50 #define CH341_BIT_DCD 0x08 51 #define CH341_BITS_MODEM_STAT 0x0f /* all bits */ 52 53 /*******************************/ 54 /* baudrate calculation factor */ 55 /*******************************/ 56 #define CH341_BAUDBASE_FACTOR 1532620800 57 #define CH341_BAUDBASE_DIVMAX 3 58 59 /* Break support - the information used to implement this was gleaned from 60 * the Net/FreeBSD uchcom.c driver by Takanori Watanabe. Domo arigato. 61 */ 62 63 #define CH341_REQ_WRITE_REG 0x9A 64 #define CH341_REQ_READ_REG 0x95 65 #define CH341_REG_BREAK1 0x05 66 #define CH341_REG_BREAK2 0x18 67 #define CH341_NBREAK_BITS_REG1 0x01 68 #define CH341_NBREAK_BITS_REG2 0x40 69 70 71 static int debug; 72 73 static struct usb_device_id id_table [] = { 74 { USB_DEVICE(0x4348, 0x5523) }, 75 { USB_DEVICE(0x1a86, 0x7523) }, 76 { }, 77 }; 78 MODULE_DEVICE_TABLE(usb, id_table); 79 80 struct ch341_private { 81 spinlock_t lock; /* access lock */ 82 wait_queue_head_t delta_msr_wait; /* wait queue for modem status */ 83 unsigned baud_rate; /* set baud rate */ 84 u8 line_control; /* set line control value RTS/DTR */ 85 u8 line_status; /* active status of modem control inputs */ 86 u8 multi_status_change; /* status changed multiple since last call */ 87 }; 88 89 static int ch341_control_out(struct usb_device *dev, u8 request, 90 u16 value, u16 index) 91 { 92 int r; 93 dbg("ch341_control_out(%02x,%02x,%04x,%04x)", USB_DIR_OUT|0x40, 94 (int)request, (int)value, (int)index); 95 96 r = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), request, 97 USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT, 98 value, index, NULL, 0, DEFAULT_TIMEOUT); 99 100 return r; 101 } 102 103 static int ch341_control_in(struct usb_device *dev, 104 u8 request, u16 value, u16 index, 105 char *buf, unsigned bufsize) 106 { 107 int r; 108 dbg("ch341_control_in(%02x,%02x,%04x,%04x,%p,%u)", USB_DIR_IN|0x40, 109 (int)request, (int)value, (int)index, buf, (int)bufsize); 110 111 r = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), request, 112 USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN, 113 value, index, buf, bufsize, DEFAULT_TIMEOUT); 114 return r; 115 } 116 117 static int ch341_set_baudrate(struct usb_device *dev, 118 struct ch341_private *priv) 119 { 120 short a, b; 121 int r; 122 unsigned long factor; 123 short divisor; 124 125 dbg("ch341_set_baudrate(%d)", priv->baud_rate); 126 127 if (!priv->baud_rate) 128 return -EINVAL; 129 factor = (CH341_BAUDBASE_FACTOR / priv->baud_rate); 130 divisor = CH341_BAUDBASE_DIVMAX; 131 132 while ((factor > 0xfff0) && divisor) { 133 factor >>= 3; 134 divisor--; 135 } 136 137 if (factor > 0xfff0) 138 return -EINVAL; 139 140 factor = 0x10000 - factor; 141 a = (factor & 0xff00) | divisor; 142 b = factor & 0xff; 143 144 r = ch341_control_out(dev, 0x9a, 0x1312, a); 145 if (!r) 146 r = ch341_control_out(dev, 0x9a, 0x0f2c, b); 147 148 return r; 149 } 150 151 static int ch341_set_handshake(struct usb_device *dev, u8 control) 152 { 153 dbg("ch341_set_handshake(0x%02x)", control); 154 return ch341_control_out(dev, 0xa4, ~control, 0); 155 } 156 157 static int ch341_get_status(struct usb_device *dev, struct ch341_private *priv) 158 { 159 char *buffer; 160 int r; 161 const unsigned size = 8; 162 unsigned long flags; 163 164 dbg("ch341_get_status()"); 165 166 buffer = kmalloc(size, GFP_KERNEL); 167 if (!buffer) 168 return -ENOMEM; 169 170 r = ch341_control_in(dev, 0x95, 0x0706, 0, buffer, size); 171 if (r < 0) 172 goto out; 173 174 /* setup the private status if available */ 175 if (r == 2) { 176 r = 0; 177 spin_lock_irqsave(&priv->lock, flags); 178 priv->line_status = (~(*buffer)) & CH341_BITS_MODEM_STAT; 179 priv->multi_status_change = 0; 180 spin_unlock_irqrestore(&priv->lock, flags); 181 } else 182 r = -EPROTO; 183 184 out: kfree(buffer); 185 return r; 186 } 187 188 /* -------------------------------------------------------------------------- */ 189 190 static int ch341_configure(struct usb_device *dev, struct ch341_private *priv) 191 { 192 char *buffer; 193 int r; 194 const unsigned size = 8; 195 196 dbg("ch341_configure()"); 197 198 buffer = kmalloc(size, GFP_KERNEL); 199 if (!buffer) 200 return -ENOMEM; 201 202 /* expect two bytes 0x27 0x00 */ 203 r = ch341_control_in(dev, 0x5f, 0, 0, buffer, size); 204 if (r < 0) 205 goto out; 206 207 r = ch341_control_out(dev, 0xa1, 0, 0); 208 if (r < 0) 209 goto out; 210 211 r = ch341_set_baudrate(dev, priv); 212 if (r < 0) 213 goto out; 214 215 /* expect two bytes 0x56 0x00 */ 216 r = ch341_control_in(dev, 0x95, 0x2518, 0, buffer, size); 217 if (r < 0) 218 goto out; 219 220 r = ch341_control_out(dev, 0x9a, 0x2518, 0x0050); 221 if (r < 0) 222 goto out; 223 224 /* expect 0xff 0xee */ 225 r = ch341_get_status(dev, priv); 226 if (r < 0) 227 goto out; 228 229 r = ch341_control_out(dev, 0xa1, 0x501f, 0xd90a); 230 if (r < 0) 231 goto out; 232 233 r = ch341_set_baudrate(dev, priv); 234 if (r < 0) 235 goto out; 236 237 r = ch341_set_handshake(dev, priv->line_control); 238 if (r < 0) 239 goto out; 240 241 /* expect 0x9f 0xee */ 242 r = ch341_get_status(dev, priv); 243 244 out: kfree(buffer); 245 return r; 246 } 247 248 /* allocate private data */ 249 static int ch341_attach(struct usb_serial *serial) 250 { 251 struct ch341_private *priv; 252 int r; 253 254 dbg("ch341_attach()"); 255 256 /* private data */ 257 priv = kzalloc(sizeof(struct ch341_private), GFP_KERNEL); 258 if (!priv) 259 return -ENOMEM; 260 261 spin_lock_init(&priv->lock); 262 init_waitqueue_head(&priv->delta_msr_wait); 263 priv->baud_rate = DEFAULT_BAUD_RATE; 264 priv->line_control = CH341_BIT_RTS | CH341_BIT_DTR; 265 266 r = ch341_configure(serial->dev, priv); 267 if (r < 0) 268 goto error; 269 270 usb_set_serial_port_data(serial->port[0], priv); 271 return 0; 272 273 error: kfree(priv); 274 return r; 275 } 276 277 static int ch341_carrier_raised(struct usb_serial_port *port) 278 { 279 struct ch341_private *priv = usb_get_serial_port_data(port); 280 if (priv->line_status & CH341_BIT_DCD) 281 return 1; 282 return 0; 283 } 284 285 static void ch341_dtr_rts(struct usb_serial_port *port, int on) 286 { 287 struct ch341_private *priv = usb_get_serial_port_data(port); 288 unsigned long flags; 289 290 dbg("%s - port %d", __func__, port->number); 291 /* drop DTR and RTS */ 292 spin_lock_irqsave(&priv->lock, flags); 293 if (on) 294 priv->line_control |= CH341_BIT_RTS | CH341_BIT_DTR; 295 else 296 priv->line_control &= ~(CH341_BIT_RTS | CH341_BIT_DTR); 297 spin_unlock_irqrestore(&priv->lock, flags); 298 ch341_set_handshake(port->serial->dev, priv->line_control); 299 wake_up_interruptible(&priv->delta_msr_wait); 300 } 301 302 static void ch341_close(struct usb_serial_port *port) 303 { 304 dbg("%s - port %d", __func__, port->number); 305 306 /* shutdown our urbs */ 307 dbg("%s - shutting down urbs", __func__); 308 usb_kill_urb(port->write_urb); 309 usb_kill_urb(port->read_urb); 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[2]; 396 397 dbg("%s()", __func__); 398 399 r = ch341_control_in(port->serial->dev, CH341_REQ_READ_REG, 400 ch341_break_reg, 0, break_reg, sizeof(break_reg)); 401 if (r < 0) { 402 printk(KERN_WARNING "%s: USB control read error whilst getting" 403 " break register contents.\n", __FILE__); 404 return; 405 } 406 dbg("%s - initial ch341 break register contents - reg1: %x, reg2: %x", 407 __func__, break_reg[0], break_reg[1]); 408 if (break_state != 0) { 409 dbg("%s - Enter break state requested", __func__); 410 break_reg[0] &= ~CH341_NBREAK_BITS_REG1; 411 break_reg[1] &= ~CH341_NBREAK_BITS_REG2; 412 } else { 413 dbg("%s - Leave break state requested", __func__); 414 break_reg[0] |= CH341_NBREAK_BITS_REG1; 415 break_reg[1] |= CH341_NBREAK_BITS_REG2; 416 } 417 dbg("%s - New ch341 break register contents - reg1: %x, reg2: %x", 418 __func__, break_reg[0], break_reg[1]); 419 reg_contents = (uint16_t)break_reg[0] | ((uint16_t)break_reg[1] << 8); 420 r = ch341_control_out(port->serial->dev, CH341_REQ_WRITE_REG, 421 ch341_break_reg, reg_contents); 422 if (r < 0) 423 printk(KERN_WARNING "%s: USB control write error whilst setting" 424 " break register contents.\n", __FILE__); 425 } 426 427 static int ch341_tiocmset(struct tty_struct *tty, struct file *file, 428 unsigned int set, unsigned int clear) 429 { 430 struct usb_serial_port *port = tty->driver_data; 431 struct ch341_private *priv = usb_get_serial_port_data(port); 432 unsigned long flags; 433 u8 control; 434 435 spin_lock_irqsave(&priv->lock, flags); 436 if (set & TIOCM_RTS) 437 priv->line_control |= CH341_BIT_RTS; 438 if (set & TIOCM_DTR) 439 priv->line_control |= CH341_BIT_DTR; 440 if (clear & TIOCM_RTS) 441 priv->line_control &= ~CH341_BIT_RTS; 442 if (clear & TIOCM_DTR) 443 priv->line_control &= ~CH341_BIT_DTR; 444 control = priv->line_control; 445 spin_unlock_irqrestore(&priv->lock, flags); 446 447 return ch341_set_handshake(port->serial->dev, control); 448 } 449 450 static void ch341_read_int_callback(struct urb *urb) 451 { 452 struct usb_serial_port *port = (struct usb_serial_port *) urb->context; 453 unsigned char *data = urb->transfer_buffer; 454 unsigned int actual_length = urb->actual_length; 455 int status; 456 457 dbg("%s (%d)", __func__, port->number); 458 459 switch (urb->status) { 460 case 0: 461 /* success */ 462 break; 463 case -ECONNRESET: 464 case -ENOENT: 465 case -ESHUTDOWN: 466 /* this urb is terminated, clean up */ 467 dbg("%s - urb shutting down with status: %d", __func__, 468 urb->status); 469 return; 470 default: 471 dbg("%s - nonzero urb status received: %d", __func__, 472 urb->status); 473 goto exit; 474 } 475 476 usb_serial_debug_data(debug, &port->dev, __func__, 477 urb->actual_length, urb->transfer_buffer); 478 479 if (actual_length >= 4) { 480 struct ch341_private *priv = usb_get_serial_port_data(port); 481 unsigned long flags; 482 483 spin_lock_irqsave(&priv->lock, flags); 484 priv->line_status = (~(data[2])) & CH341_BITS_MODEM_STAT; 485 if ((data[1] & CH341_MULT_STAT)) 486 priv->multi_status_change = 1; 487 spin_unlock_irqrestore(&priv->lock, flags); 488 wake_up_interruptible(&priv->delta_msr_wait); 489 } 490 491 exit: 492 status = usb_submit_urb(urb, GFP_ATOMIC); 493 if (status) 494 dev_err(&urb->dev->dev, 495 "%s - usb_submit_urb failed with result %d\n", 496 __func__, status); 497 } 498 499 static int wait_modem_info(struct usb_serial_port *port, unsigned int arg) 500 { 501 struct ch341_private *priv = usb_get_serial_port_data(port); 502 unsigned long flags; 503 u8 prevstatus; 504 u8 status; 505 u8 changed; 506 u8 multi_change = 0; 507 508 spin_lock_irqsave(&priv->lock, flags); 509 prevstatus = priv->line_status; 510 priv->multi_status_change = 0; 511 spin_unlock_irqrestore(&priv->lock, flags); 512 513 while (!multi_change) { 514 interruptible_sleep_on(&priv->delta_msr_wait); 515 /* see if a signal did it */ 516 if (signal_pending(current)) 517 return -ERESTARTSYS; 518 519 spin_lock_irqsave(&priv->lock, flags); 520 status = priv->line_status; 521 multi_change = priv->multi_status_change; 522 spin_unlock_irqrestore(&priv->lock, flags); 523 524 changed = prevstatus ^ status; 525 526 if (((arg & TIOCM_RNG) && (changed & CH341_BIT_RI)) || 527 ((arg & TIOCM_DSR) && (changed & CH341_BIT_DSR)) || 528 ((arg & TIOCM_CD) && (changed & CH341_BIT_DCD)) || 529 ((arg & TIOCM_CTS) && (changed & CH341_BIT_CTS))) { 530 return 0; 531 } 532 prevstatus = status; 533 } 534 535 return 0; 536 } 537 538 /*static int ch341_ioctl(struct usb_serial_port *port, struct file *file,*/ 539 static int ch341_ioctl(struct tty_struct *tty, struct file *file, 540 unsigned int cmd, unsigned long arg) 541 { 542 struct usb_serial_port *port = tty->driver_data; 543 dbg("%s (%d) cmd = 0x%04x", __func__, port->number, cmd); 544 545 switch (cmd) { 546 case TIOCMIWAIT: 547 dbg("%s (%d) TIOCMIWAIT", __func__, port->number); 548 return wait_modem_info(port, arg); 549 550 default: 551 dbg("%s not supported = 0x%04x", __func__, cmd); 552 break; 553 } 554 555 return -ENOIOCTLCMD; 556 } 557 558 static int ch341_tiocmget(struct tty_struct *tty, struct file *file) 559 { 560 struct usb_serial_port *port = tty->driver_data; 561 struct ch341_private *priv = usb_get_serial_port_data(port); 562 unsigned long flags; 563 u8 mcr; 564 u8 status; 565 unsigned int result; 566 567 dbg("%s (%d)", __func__, port->number); 568 569 spin_lock_irqsave(&priv->lock, flags); 570 mcr = priv->line_control; 571 status = priv->line_status; 572 spin_unlock_irqrestore(&priv->lock, flags); 573 574 result = ((mcr & CH341_BIT_DTR) ? TIOCM_DTR : 0) 575 | ((mcr & CH341_BIT_RTS) ? TIOCM_RTS : 0) 576 | ((status & CH341_BIT_CTS) ? TIOCM_CTS : 0) 577 | ((status & CH341_BIT_DSR) ? TIOCM_DSR : 0) 578 | ((status & CH341_BIT_RI) ? TIOCM_RI : 0) 579 | ((status & CH341_BIT_DCD) ? TIOCM_CD : 0); 580 581 dbg("%s - result = %x", __func__, result); 582 583 return result; 584 } 585 586 587 static int ch341_reset_resume(struct usb_interface *intf) 588 { 589 struct usb_device *dev = interface_to_usbdev(intf); 590 struct usb_serial *serial = NULL; 591 struct ch341_private *priv; 592 593 serial = usb_get_intfdata(intf); 594 priv = usb_get_serial_port_data(serial->port[0]); 595 596 /*reconfigure ch341 serial port after bus-reset*/ 597 ch341_configure(dev, priv); 598 599 usb_serial_resume(intf); 600 601 return 0; 602 } 603 604 static struct usb_driver ch341_driver = { 605 .name = "ch341", 606 .probe = usb_serial_probe, 607 .disconnect = usb_serial_disconnect, 608 .suspend = usb_serial_suspend, 609 .resume = usb_serial_resume, 610 .reset_resume = ch341_reset_resume, 611 .id_table = id_table, 612 .no_dynamic_id = 1, 613 .supports_autosuspend = 1, 614 }; 615 616 static struct usb_serial_driver ch341_device = { 617 .driver = { 618 .owner = THIS_MODULE, 619 .name = "ch341-uart", 620 }, 621 .id_table = id_table, 622 .usb_driver = &ch341_driver, 623 .num_ports = 1, 624 .open = ch341_open, 625 .dtr_rts = ch341_dtr_rts, 626 .carrier_raised = ch341_carrier_raised, 627 .close = ch341_close, 628 .ioctl = ch341_ioctl, 629 .set_termios = ch341_set_termios, 630 .break_ctl = ch341_break_ctl, 631 .tiocmget = ch341_tiocmget, 632 .tiocmset = ch341_tiocmset, 633 .read_int_callback = ch341_read_int_callback, 634 .attach = ch341_attach, 635 }; 636 637 static int __init ch341_init(void) 638 { 639 int retval; 640 641 retval = usb_serial_register(&ch341_device); 642 if (retval) 643 return retval; 644 retval = usb_register(&ch341_driver); 645 if (retval) 646 usb_serial_deregister(&ch341_device); 647 return retval; 648 } 649 650 static void __exit ch341_exit(void) 651 { 652 usb_deregister(&ch341_driver); 653 usb_serial_deregister(&ch341_device); 654 } 655 656 module_init(ch341_init); 657 module_exit(ch341_exit); 658 MODULE_LICENSE("GPL"); 659 660 module_param(debug, bool, S_IRUGO | S_IWUSR); 661 MODULE_PARM_DESC(debug, "Debug enabled or not"); 662 663 /* EOF ch341.c */ 664