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 static int debug; 60 61 static struct usb_device_id id_table [] = { 62 { USB_DEVICE(0x4348, 0x5523) }, 63 { USB_DEVICE(0x1a86, 0x7523) }, 64 { }, 65 }; 66 MODULE_DEVICE_TABLE(usb, id_table); 67 68 struct ch341_private { 69 spinlock_t lock; /* access lock */ 70 wait_queue_head_t delta_msr_wait; /* wait queue for modem status */ 71 unsigned baud_rate; /* set baud rate */ 72 u8 line_control; /* set line control value RTS/DTR */ 73 u8 line_status; /* active status of modem control inputs */ 74 u8 multi_status_change; /* status changed multiple since last call */ 75 }; 76 77 static int ch341_control_out(struct usb_device *dev, u8 request, 78 u16 value, u16 index) 79 { 80 int r; 81 dbg("ch341_control_out(%02x,%02x,%04x,%04x)", USB_DIR_OUT|0x40, 82 (int)request, (int)value, (int)index); 83 84 r = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), request, 85 USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT, 86 value, index, NULL, 0, DEFAULT_TIMEOUT); 87 88 return r; 89 } 90 91 static int ch341_control_in(struct usb_device *dev, 92 u8 request, u16 value, u16 index, 93 char *buf, unsigned bufsize) 94 { 95 int r; 96 dbg("ch341_control_in(%02x,%02x,%04x,%04x,%p,%u)", USB_DIR_IN|0x40, 97 (int)request, (int)value, (int)index, buf, (int)bufsize); 98 99 r = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), request, 100 USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN, 101 value, index, buf, bufsize, DEFAULT_TIMEOUT); 102 return r; 103 } 104 105 static int ch341_set_baudrate(struct usb_device *dev, 106 struct ch341_private *priv) 107 { 108 short a, b; 109 int r; 110 unsigned long factor; 111 short divisor; 112 113 dbg("ch341_set_baudrate(%d)", priv->baud_rate); 114 115 if (!priv->baud_rate) 116 return -EINVAL; 117 factor = (CH341_BAUDBASE_FACTOR / priv->baud_rate); 118 divisor = CH341_BAUDBASE_DIVMAX; 119 120 while ((factor > 0xfff0) && divisor) { 121 factor >>= 3; 122 divisor--; 123 } 124 125 if (factor > 0xfff0) 126 return -EINVAL; 127 128 factor = 0x10000 - factor; 129 a = (factor & 0xff00) | divisor; 130 b = factor & 0xff; 131 132 r = ch341_control_out(dev, 0x9a, 0x1312, a); 133 if (!r) 134 r = ch341_control_out(dev, 0x9a, 0x0f2c, b); 135 136 return r; 137 } 138 139 static int ch341_set_handshake(struct usb_device *dev, u8 control) 140 { 141 dbg("ch341_set_handshake(0x%02x)", control); 142 return ch341_control_out(dev, 0xa4, ~control, 0); 143 } 144 145 static int ch341_get_status(struct usb_device *dev, struct ch341_private *priv) 146 { 147 char *buffer; 148 int r; 149 const unsigned size = 8; 150 unsigned long flags; 151 152 dbg("ch341_get_status()"); 153 154 buffer = kmalloc(size, GFP_KERNEL); 155 if (!buffer) 156 return -ENOMEM; 157 158 r = ch341_control_in(dev, 0x95, 0x0706, 0, buffer, size); 159 if (r < 0) 160 goto out; 161 162 /* setup the private status if available */ 163 if (r == 2) { 164 r = 0; 165 spin_lock_irqsave(&priv->lock, flags); 166 priv->line_status = (~(*buffer)) & CH341_BITS_MODEM_STAT; 167 priv->multi_status_change = 0; 168 spin_unlock_irqrestore(&priv->lock, flags); 169 } else 170 r = -EPROTO; 171 172 out: kfree(buffer); 173 return r; 174 } 175 176 /* -------------------------------------------------------------------------- */ 177 178 static int ch341_configure(struct usb_device *dev, struct ch341_private *priv) 179 { 180 char *buffer; 181 int r; 182 const unsigned size = 8; 183 184 dbg("ch341_configure()"); 185 186 buffer = kmalloc(size, GFP_KERNEL); 187 if (!buffer) 188 return -ENOMEM; 189 190 /* expect two bytes 0x27 0x00 */ 191 r = ch341_control_in(dev, 0x5f, 0, 0, buffer, size); 192 if (r < 0) 193 goto out; 194 195 r = ch341_control_out(dev, 0xa1, 0, 0); 196 if (r < 0) 197 goto out; 198 199 r = ch341_set_baudrate(dev, priv); 200 if (r < 0) 201 goto out; 202 203 /* expect two bytes 0x56 0x00 */ 204 r = ch341_control_in(dev, 0x95, 0x2518, 0, buffer, size); 205 if (r < 0) 206 goto out; 207 208 r = ch341_control_out(dev, 0x9a, 0x2518, 0x0050); 209 if (r < 0) 210 goto out; 211 212 /* expect 0xff 0xee */ 213 r = ch341_get_status(dev, priv); 214 if (r < 0) 215 goto out; 216 217 r = ch341_control_out(dev, 0xa1, 0x501f, 0xd90a); 218 if (r < 0) 219 goto out; 220 221 r = ch341_set_baudrate(dev, priv); 222 if (r < 0) 223 goto out; 224 225 r = ch341_set_handshake(dev, priv->line_control); 226 if (r < 0) 227 goto out; 228 229 /* expect 0x9f 0xee */ 230 r = ch341_get_status(dev, priv); 231 232 out: kfree(buffer); 233 return r; 234 } 235 236 /* allocate private data */ 237 static int ch341_attach(struct usb_serial *serial) 238 { 239 struct ch341_private *priv; 240 int r; 241 242 dbg("ch341_attach()"); 243 244 /* private data */ 245 priv = kzalloc(sizeof(struct ch341_private), GFP_KERNEL); 246 if (!priv) 247 return -ENOMEM; 248 249 spin_lock_init(&priv->lock); 250 init_waitqueue_head(&priv->delta_msr_wait); 251 priv->baud_rate = DEFAULT_BAUD_RATE; 252 priv->line_control = CH341_BIT_RTS | CH341_BIT_DTR; 253 254 r = ch341_configure(serial->dev, priv); 255 if (r < 0) 256 goto error; 257 258 usb_set_serial_port_data(serial->port[0], priv); 259 return 0; 260 261 error: kfree(priv); 262 return r; 263 } 264 265 static void ch341_close(struct tty_struct *tty, struct usb_serial_port *port, 266 struct file *filp) 267 { 268 struct ch341_private *priv = usb_get_serial_port_data(port); 269 unsigned long flags; 270 unsigned int c_cflag; 271 272 dbg("%s - port %d", __func__, port->number); 273 274 /* shutdown our urbs */ 275 dbg("%s - shutting down urbs", __func__); 276 usb_kill_urb(port->write_urb); 277 usb_kill_urb(port->read_urb); 278 usb_kill_urb(port->interrupt_in_urb); 279 280 if (tty) { 281 c_cflag = tty->termios->c_cflag; 282 if (c_cflag & HUPCL) { 283 /* drop DTR and RTS */ 284 spin_lock_irqsave(&priv->lock, flags); 285 priv->line_control = 0; 286 spin_unlock_irqrestore(&priv->lock, flags); 287 ch341_set_handshake(port->serial->dev, 0); 288 } 289 } 290 wake_up_interruptible(&priv->delta_msr_wait); 291 } 292 293 294 /* open this device, set default parameters */ 295 static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port, 296 struct file *filp) 297 { 298 struct usb_serial *serial = port->serial; 299 struct ch341_private *priv = usb_get_serial_port_data(serial->port[0]); 300 int r; 301 302 dbg("ch341_open()"); 303 304 priv->baud_rate = DEFAULT_BAUD_RATE; 305 priv->line_control = CH341_BIT_RTS | CH341_BIT_DTR; 306 307 r = ch341_configure(serial->dev, priv); 308 if (r) 309 goto out; 310 311 r = ch341_set_handshake(serial->dev, priv->line_control); 312 if (r) 313 goto out; 314 315 r = ch341_set_baudrate(serial->dev, priv); 316 if (r) 317 goto out; 318 319 dbg("%s - submitting interrupt urb", __func__); 320 port->interrupt_in_urb->dev = serial->dev; 321 r = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL); 322 if (r) { 323 dev_err(&port->dev, "%s - failed submitting interrupt urb," 324 " error %d\n", __func__, r); 325 ch341_close(tty, port, NULL); 326 return -EPROTO; 327 } 328 329 r = usb_serial_generic_open(tty, port, filp); 330 331 out: return r; 332 } 333 334 /* Old_termios contains the original termios settings and 335 * tty->termios contains the new setting to be used. 336 */ 337 static void ch341_set_termios(struct tty_struct *tty, 338 struct usb_serial_port *port, struct ktermios *old_termios) 339 { 340 struct ch341_private *priv = usb_get_serial_port_data(port); 341 unsigned baud_rate; 342 unsigned long flags; 343 344 dbg("ch341_set_termios()"); 345 346 if (!tty || !tty->termios) 347 return; 348 349 baud_rate = tty_get_baud_rate(tty); 350 351 priv->baud_rate = baud_rate; 352 353 if (baud_rate) { 354 spin_lock_irqsave(&priv->lock, flags); 355 priv->line_control |= (CH341_BIT_DTR | CH341_BIT_RTS); 356 spin_unlock_irqrestore(&priv->lock, flags); 357 ch341_set_baudrate(port->serial->dev, priv); 358 } else { 359 spin_lock_irqsave(&priv->lock, flags); 360 priv->line_control &= ~(CH341_BIT_DTR | CH341_BIT_RTS); 361 spin_unlock_irqrestore(&priv->lock, flags); 362 } 363 364 ch341_set_handshake(port->serial->dev, priv->line_control); 365 366 /* Unimplemented: 367 * (cflag & CSIZE) : data bits [5, 8] 368 * (cflag & PARENB) : parity {NONE, EVEN, ODD} 369 * (cflag & CSTOPB) : stop bits [1, 2] 370 */ 371 } 372 373 static int ch341_tiocmset(struct tty_struct *tty, struct file *file, 374 unsigned int set, unsigned int clear) 375 { 376 struct usb_serial_port *port = tty->driver_data; 377 struct ch341_private *priv = usb_get_serial_port_data(port); 378 unsigned long flags; 379 u8 control; 380 381 spin_lock_irqsave(&priv->lock, flags); 382 if (set & TIOCM_RTS) 383 priv->line_control |= CH341_BIT_RTS; 384 if (set & TIOCM_DTR) 385 priv->line_control |= CH341_BIT_DTR; 386 if (clear & TIOCM_RTS) 387 priv->line_control &= ~CH341_BIT_RTS; 388 if (clear & TIOCM_DTR) 389 priv->line_control &= ~CH341_BIT_DTR; 390 control = priv->line_control; 391 spin_unlock_irqrestore(&priv->lock, flags); 392 393 return ch341_set_handshake(port->serial->dev, control); 394 } 395 396 static void ch341_read_int_callback(struct urb *urb) 397 { 398 struct usb_serial_port *port = (struct usb_serial_port *) urb->context; 399 unsigned char *data = urb->transfer_buffer; 400 unsigned int actual_length = urb->actual_length; 401 int status; 402 403 dbg("%s (%d)", __func__, port->number); 404 405 switch (urb->status) { 406 case 0: 407 /* success */ 408 break; 409 case -ECONNRESET: 410 case -ENOENT: 411 case -ESHUTDOWN: 412 /* this urb is terminated, clean up */ 413 dbg("%s - urb shutting down with status: %d", __func__, 414 urb->status); 415 return; 416 default: 417 dbg("%s - nonzero urb status received: %d", __func__, 418 urb->status); 419 goto exit; 420 } 421 422 usb_serial_debug_data(debug, &port->dev, __func__, 423 urb->actual_length, urb->transfer_buffer); 424 425 if (actual_length >= 4) { 426 struct ch341_private *priv = usb_get_serial_port_data(port); 427 unsigned long flags; 428 429 spin_lock_irqsave(&priv->lock, flags); 430 priv->line_status = (~(data[2])) & CH341_BITS_MODEM_STAT; 431 if ((data[1] & CH341_MULT_STAT)) 432 priv->multi_status_change = 1; 433 spin_unlock_irqrestore(&priv->lock, flags); 434 wake_up_interruptible(&priv->delta_msr_wait); 435 } 436 437 exit: 438 status = usb_submit_urb(urb, GFP_ATOMIC); 439 if (status) 440 dev_err(&urb->dev->dev, 441 "%s - usb_submit_urb failed with result %d\n", 442 __func__, status); 443 } 444 445 static int wait_modem_info(struct usb_serial_port *port, unsigned int arg) 446 { 447 struct ch341_private *priv = usb_get_serial_port_data(port); 448 unsigned long flags; 449 u8 prevstatus; 450 u8 status; 451 u8 changed; 452 u8 multi_change = 0; 453 454 spin_lock_irqsave(&priv->lock, flags); 455 prevstatus = priv->line_status; 456 priv->multi_status_change = 0; 457 spin_unlock_irqrestore(&priv->lock, flags); 458 459 while (!multi_change) { 460 interruptible_sleep_on(&priv->delta_msr_wait); 461 /* see if a signal did it */ 462 if (signal_pending(current)) 463 return -ERESTARTSYS; 464 465 spin_lock_irqsave(&priv->lock, flags); 466 status = priv->line_status; 467 multi_change = priv->multi_status_change; 468 spin_unlock_irqrestore(&priv->lock, flags); 469 470 changed = prevstatus ^ status; 471 472 if (((arg & TIOCM_RNG) && (changed & CH341_BIT_RI)) || 473 ((arg & TIOCM_DSR) && (changed & CH341_BIT_DSR)) || 474 ((arg & TIOCM_CD) && (changed & CH341_BIT_DCD)) || 475 ((arg & TIOCM_CTS) && (changed & CH341_BIT_CTS))) { 476 return 0; 477 } 478 prevstatus = status; 479 } 480 481 return 0; 482 } 483 484 /*static int ch341_ioctl(struct usb_serial_port *port, struct file *file,*/ 485 static int ch341_ioctl(struct tty_struct *tty, struct file *file, 486 unsigned int cmd, unsigned long arg) 487 { 488 struct usb_serial_port *port = tty->driver_data; 489 dbg("%s (%d) cmd = 0x%04x", __func__, port->number, cmd); 490 491 switch (cmd) { 492 case TIOCMIWAIT: 493 dbg("%s (%d) TIOCMIWAIT", __func__, port->number); 494 return wait_modem_info(port, arg); 495 496 default: 497 dbg("%s not supported = 0x%04x", __func__, cmd); 498 break; 499 } 500 501 return -ENOIOCTLCMD; 502 } 503 504 static int ch341_tiocmget(struct tty_struct *tty, struct file *file) 505 { 506 struct usb_serial_port *port = tty->driver_data; 507 struct ch341_private *priv = usb_get_serial_port_data(port); 508 unsigned long flags; 509 u8 mcr; 510 u8 status; 511 unsigned int result; 512 513 dbg("%s (%d)", __func__, port->number); 514 515 spin_lock_irqsave(&priv->lock, flags); 516 mcr = priv->line_control; 517 status = priv->line_status; 518 spin_unlock_irqrestore(&priv->lock, flags); 519 520 result = ((mcr & CH341_BIT_DTR) ? TIOCM_DTR : 0) 521 | ((mcr & CH341_BIT_RTS) ? TIOCM_RTS : 0) 522 | ((status & CH341_BIT_CTS) ? TIOCM_CTS : 0) 523 | ((status & CH341_BIT_DSR) ? TIOCM_DSR : 0) 524 | ((status & CH341_BIT_RI) ? TIOCM_RI : 0) 525 | ((status & CH341_BIT_DCD) ? TIOCM_CD : 0); 526 527 dbg("%s - result = %x", __func__, result); 528 529 return result; 530 } 531 532 533 static int ch341_reset_resume(struct usb_interface *intf) 534 { 535 struct usb_device *dev = interface_to_usbdev(intf); 536 struct usb_serial *serial = NULL; 537 struct ch341_private *priv; 538 539 serial = usb_get_intfdata(intf); 540 priv = usb_get_serial_port_data(serial->port[0]); 541 542 /*reconfigure ch341 serial port after bus-reset*/ 543 ch341_configure(dev, priv); 544 545 usb_serial_resume(intf); 546 547 return 0; 548 } 549 550 static struct usb_driver ch341_driver = { 551 .name = "ch341", 552 .probe = usb_serial_probe, 553 .disconnect = usb_serial_disconnect, 554 .suspend = usb_serial_suspend, 555 .resume = usb_serial_resume, 556 .reset_resume = ch341_reset_resume, 557 .id_table = id_table, 558 .no_dynamic_id = 1, 559 .supports_autosuspend = 1, 560 }; 561 562 static struct usb_serial_driver ch341_device = { 563 .driver = { 564 .owner = THIS_MODULE, 565 .name = "ch341-uart", 566 }, 567 .id_table = id_table, 568 .usb_driver = &ch341_driver, 569 .num_ports = 1, 570 .open = ch341_open, 571 .close = ch341_close, 572 .ioctl = ch341_ioctl, 573 .set_termios = ch341_set_termios, 574 .tiocmget = ch341_tiocmget, 575 .tiocmset = ch341_tiocmset, 576 .read_int_callback = ch341_read_int_callback, 577 .attach = ch341_attach, 578 }; 579 580 static int __init ch341_init(void) 581 { 582 int retval; 583 584 retval = usb_serial_register(&ch341_device); 585 if (retval) 586 return retval; 587 retval = usb_register(&ch341_driver); 588 if (retval) 589 usb_serial_deregister(&ch341_device); 590 return retval; 591 } 592 593 static void __exit ch341_exit(void) 594 { 595 usb_deregister(&ch341_driver); 596 usb_serial_deregister(&ch341_device); 597 } 598 599 module_init(ch341_init); 600 module_exit(ch341_exit); 601 MODULE_LICENSE("GPL"); 602 603 module_param(debug, bool, S_IRUGO | S_IWUSR); 604 MODULE_PARM_DESC(debug, "Debug enabled or not"); 605 606 /* EOF ch341.c */ 607