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 int ch341_carrier_raised(struct usb_serial_port *port) 266 { 267 struct ch341_private *priv = usb_get_serial_port_data(port); 268 if (priv->line_status & CH341_BIT_DCD) 269 return 1; 270 return 0; 271 } 272 273 static void ch341_dtr_rts(struct usb_serial_port *port, int on) 274 { 275 struct ch341_private *priv = usb_get_serial_port_data(port); 276 unsigned long flags; 277 278 dbg("%s - port %d", __func__, port->number); 279 /* drop DTR and RTS */ 280 spin_lock_irqsave(&priv->lock, flags); 281 if (on) 282 priv->line_control |= CH341_BIT_RTS | CH341_BIT_DTR; 283 else 284 priv->line_control &= ~(CH341_BIT_RTS | CH341_BIT_DTR); 285 spin_unlock_irqrestore(&priv->lock, flags); 286 ch341_set_handshake(port->serial->dev, priv->line_control); 287 wake_up_interruptible(&priv->delta_msr_wait); 288 } 289 290 static void ch341_close(struct usb_serial_port *port) 291 { 292 dbg("%s - port %d", __func__, port->number); 293 294 /* shutdown our urbs */ 295 dbg("%s - shutting down urbs", __func__); 296 usb_kill_urb(port->write_urb); 297 usb_kill_urb(port->read_urb); 298 usb_kill_urb(port->interrupt_in_urb); 299 } 300 301 302 /* open this device, set default parameters */ 303 static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port) 304 { 305 struct usb_serial *serial = port->serial; 306 struct ch341_private *priv = usb_get_serial_port_data(serial->port[0]); 307 int r; 308 309 dbg("ch341_open()"); 310 311 priv->baud_rate = DEFAULT_BAUD_RATE; 312 313 r = ch341_configure(serial->dev, priv); 314 if (r) 315 goto out; 316 317 r = ch341_set_handshake(serial->dev, priv->line_control); 318 if (r) 319 goto out; 320 321 r = ch341_set_baudrate(serial->dev, priv); 322 if (r) 323 goto out; 324 325 dbg("%s - submitting interrupt urb", __func__); 326 port->interrupt_in_urb->dev = serial->dev; 327 r = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL); 328 if (r) { 329 dev_err(&port->dev, "%s - failed submitting interrupt urb," 330 " error %d\n", __func__, r); 331 ch341_close(port); 332 return -EPROTO; 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 dbg("ch341_set_termios()"); 351 352 baud_rate = tty_get_baud_rate(tty); 353 354 priv->baud_rate = baud_rate; 355 356 if (baud_rate) { 357 spin_lock_irqsave(&priv->lock, flags); 358 priv->line_control |= (CH341_BIT_DTR | CH341_BIT_RTS); 359 spin_unlock_irqrestore(&priv->lock, flags); 360 ch341_set_baudrate(port->serial->dev, priv); 361 } else { 362 spin_lock_irqsave(&priv->lock, flags); 363 priv->line_control &= ~(CH341_BIT_DTR | CH341_BIT_RTS); 364 spin_unlock_irqrestore(&priv->lock, flags); 365 } 366 367 ch341_set_handshake(port->serial->dev, priv->line_control); 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 } 375 376 static int ch341_tiocmset(struct tty_struct *tty, struct file *file, 377 unsigned int set, unsigned int clear) 378 { 379 struct usb_serial_port *port = tty->driver_data; 380 struct ch341_private *priv = usb_get_serial_port_data(port); 381 unsigned long flags; 382 u8 control; 383 384 spin_lock_irqsave(&priv->lock, flags); 385 if (set & TIOCM_RTS) 386 priv->line_control |= CH341_BIT_RTS; 387 if (set & TIOCM_DTR) 388 priv->line_control |= CH341_BIT_DTR; 389 if (clear & TIOCM_RTS) 390 priv->line_control &= ~CH341_BIT_RTS; 391 if (clear & TIOCM_DTR) 392 priv->line_control &= ~CH341_BIT_DTR; 393 control = priv->line_control; 394 spin_unlock_irqrestore(&priv->lock, flags); 395 396 return ch341_set_handshake(port->serial->dev, control); 397 } 398 399 static void ch341_read_int_callback(struct urb *urb) 400 { 401 struct usb_serial_port *port = (struct usb_serial_port *) urb->context; 402 unsigned char *data = urb->transfer_buffer; 403 unsigned int actual_length = urb->actual_length; 404 int status; 405 406 dbg("%s (%d)", __func__, port->number); 407 408 switch (urb->status) { 409 case 0: 410 /* success */ 411 break; 412 case -ECONNRESET: 413 case -ENOENT: 414 case -ESHUTDOWN: 415 /* this urb is terminated, clean up */ 416 dbg("%s - urb shutting down with status: %d", __func__, 417 urb->status); 418 return; 419 default: 420 dbg("%s - nonzero urb status received: %d", __func__, 421 urb->status); 422 goto exit; 423 } 424 425 usb_serial_debug_data(debug, &port->dev, __func__, 426 urb->actual_length, urb->transfer_buffer); 427 428 if (actual_length >= 4) { 429 struct ch341_private *priv = usb_get_serial_port_data(port); 430 unsigned long flags; 431 432 spin_lock_irqsave(&priv->lock, flags); 433 priv->line_status = (~(data[2])) & CH341_BITS_MODEM_STAT; 434 if ((data[1] & CH341_MULT_STAT)) 435 priv->multi_status_change = 1; 436 spin_unlock_irqrestore(&priv->lock, flags); 437 wake_up_interruptible(&priv->delta_msr_wait); 438 } 439 440 exit: 441 status = usb_submit_urb(urb, GFP_ATOMIC); 442 if (status) 443 dev_err(&urb->dev->dev, 444 "%s - usb_submit_urb failed with result %d\n", 445 __func__, status); 446 } 447 448 static int wait_modem_info(struct usb_serial_port *port, unsigned int arg) 449 { 450 struct ch341_private *priv = usb_get_serial_port_data(port); 451 unsigned long flags; 452 u8 prevstatus; 453 u8 status; 454 u8 changed; 455 u8 multi_change = 0; 456 457 spin_lock_irqsave(&priv->lock, flags); 458 prevstatus = priv->line_status; 459 priv->multi_status_change = 0; 460 spin_unlock_irqrestore(&priv->lock, flags); 461 462 while (!multi_change) { 463 interruptible_sleep_on(&priv->delta_msr_wait); 464 /* see if a signal did it */ 465 if (signal_pending(current)) 466 return -ERESTARTSYS; 467 468 spin_lock_irqsave(&priv->lock, flags); 469 status = priv->line_status; 470 multi_change = priv->multi_status_change; 471 spin_unlock_irqrestore(&priv->lock, flags); 472 473 changed = prevstatus ^ status; 474 475 if (((arg & TIOCM_RNG) && (changed & CH341_BIT_RI)) || 476 ((arg & TIOCM_DSR) && (changed & CH341_BIT_DSR)) || 477 ((arg & TIOCM_CD) && (changed & CH341_BIT_DCD)) || 478 ((arg & TIOCM_CTS) && (changed & CH341_BIT_CTS))) { 479 return 0; 480 } 481 prevstatus = status; 482 } 483 484 return 0; 485 } 486 487 /*static int ch341_ioctl(struct usb_serial_port *port, struct file *file,*/ 488 static int ch341_ioctl(struct tty_struct *tty, struct file *file, 489 unsigned int cmd, unsigned long arg) 490 { 491 struct usb_serial_port *port = tty->driver_data; 492 dbg("%s (%d) cmd = 0x%04x", __func__, port->number, cmd); 493 494 switch (cmd) { 495 case TIOCMIWAIT: 496 dbg("%s (%d) TIOCMIWAIT", __func__, port->number); 497 return wait_modem_info(port, arg); 498 499 default: 500 dbg("%s not supported = 0x%04x", __func__, cmd); 501 break; 502 } 503 504 return -ENOIOCTLCMD; 505 } 506 507 static int ch341_tiocmget(struct tty_struct *tty, struct file *file) 508 { 509 struct usb_serial_port *port = tty->driver_data; 510 struct ch341_private *priv = usb_get_serial_port_data(port); 511 unsigned long flags; 512 u8 mcr; 513 u8 status; 514 unsigned int result; 515 516 dbg("%s (%d)", __func__, port->number); 517 518 spin_lock_irqsave(&priv->lock, flags); 519 mcr = priv->line_control; 520 status = priv->line_status; 521 spin_unlock_irqrestore(&priv->lock, flags); 522 523 result = ((mcr & CH341_BIT_DTR) ? TIOCM_DTR : 0) 524 | ((mcr & CH341_BIT_RTS) ? TIOCM_RTS : 0) 525 | ((status & CH341_BIT_CTS) ? TIOCM_CTS : 0) 526 | ((status & CH341_BIT_DSR) ? TIOCM_DSR : 0) 527 | ((status & CH341_BIT_RI) ? TIOCM_RI : 0) 528 | ((status & CH341_BIT_DCD) ? TIOCM_CD : 0); 529 530 dbg("%s - result = %x", __func__, result); 531 532 return result; 533 } 534 535 536 static int ch341_reset_resume(struct usb_interface *intf) 537 { 538 struct usb_device *dev = interface_to_usbdev(intf); 539 struct usb_serial *serial = NULL; 540 struct ch341_private *priv; 541 542 serial = usb_get_intfdata(intf); 543 priv = usb_get_serial_port_data(serial->port[0]); 544 545 /*reconfigure ch341 serial port after bus-reset*/ 546 ch341_configure(dev, priv); 547 548 usb_serial_resume(intf); 549 550 return 0; 551 } 552 553 static struct usb_driver ch341_driver = { 554 .name = "ch341", 555 .probe = usb_serial_probe, 556 .disconnect = usb_serial_disconnect, 557 .suspend = usb_serial_suspend, 558 .resume = usb_serial_resume, 559 .reset_resume = ch341_reset_resume, 560 .id_table = id_table, 561 .no_dynamic_id = 1, 562 .supports_autosuspend = 1, 563 }; 564 565 static struct usb_serial_driver ch341_device = { 566 .driver = { 567 .owner = THIS_MODULE, 568 .name = "ch341-uart", 569 }, 570 .id_table = id_table, 571 .usb_driver = &ch341_driver, 572 .num_ports = 1, 573 .open = ch341_open, 574 .dtr_rts = ch341_dtr_rts, 575 .carrier_raised = ch341_carrier_raised, 576 .close = ch341_close, 577 .ioctl = ch341_ioctl, 578 .set_termios = ch341_set_termios, 579 .tiocmget = ch341_tiocmget, 580 .tiocmset = ch341_tiocmset, 581 .read_int_callback = ch341_read_int_callback, 582 .attach = ch341_attach, 583 }; 584 585 static int __init ch341_init(void) 586 { 587 int retval; 588 589 retval = usb_serial_register(&ch341_device); 590 if (retval) 591 return retval; 592 retval = usb_register(&ch341_driver); 593 if (retval) 594 usb_serial_deregister(&ch341_device); 595 return retval; 596 } 597 598 static void __exit ch341_exit(void) 599 { 600 usb_deregister(&ch341_driver); 601 usb_serial_deregister(&ch341_device); 602 } 603 604 module_init(ch341_init); 605 module_exit(ch341_exit); 606 MODULE_LICENSE("GPL"); 607 608 module_param(debug, bool, S_IRUGO | S_IWUSR); 609 MODULE_PARM_DESC(debug, "Debug enabled or not"); 610 611 /* EOF ch341.c */ 612