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 73static int debug; 74 75static const struct usb_device_id id_table[] = { 76 { USB_DEVICE(0x4348, 0x5523) }, 77 { USB_DEVICE(0x1a86, 0x7523) }, 78 { }, 79}; 80MODULE_DEVICE_TABLE(usb, id_table); 81 82struct ch341_private { 83 spinlock_t lock; /* access lock */ 84 wait_queue_head_t delta_msr_wait; /* wait queue for modem status */ 85 unsigned baud_rate; /* set baud rate */ 86 u8 line_control; /* set line control value RTS/DTR */ 87 u8 line_status; /* active status of modem control inputs */ 88 u8 multi_status_change; /* status changed multiple since last call */ 89}; 90 91static int ch341_control_out(struct usb_device *dev, u8 request, 92 u16 value, u16 index) 93{ 94 int r; 95 dbg("ch341_control_out(%02x,%02x,%04x,%04x)", USB_DIR_OUT|0x40, 96 (int)request, (int)value, (int)index); 97 98 r = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), request, 99 USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT, 100 value, index, NULL, 0, DEFAULT_TIMEOUT); 101 102 return r; 103} 104 105static int ch341_control_in(struct usb_device *dev, 106 u8 request, u16 value, u16 index, 107 char *buf, unsigned bufsize) 108{ 109 int r; 110 dbg("ch341_control_in(%02x,%02x,%04x,%04x,%p,%u)", USB_DIR_IN|0x40, 111 (int)request, (int)value, (int)index, buf, (int)bufsize); 112 113 r = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), request, 114 USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN, 115 value, index, buf, bufsize, DEFAULT_TIMEOUT); 116 return r; 117} 118 119static int ch341_set_baudrate(struct usb_device *dev, 120 struct ch341_private *priv) 121{ 122 short a, b; 123 int r; 124 unsigned long factor; 125 short divisor; 126 127 dbg("ch341_set_baudrate(%d)", priv->baud_rate); 128 129 if (!priv->baud_rate) 130 return -EINVAL; 131 factor = (CH341_BAUDBASE_FACTOR / priv->baud_rate); 132 divisor = CH341_BAUDBASE_DIVMAX; 133 134 while ((factor > 0xfff0) && divisor) { 135 factor >>= 3; 136 divisor--; 137 } 138 139 if (factor > 0xfff0) 140 return -EINVAL; 141 142 factor = 0x10000 - factor; 143 a = (factor & 0xff00) | divisor; 144 b = factor & 0xff; 145 146 r = ch341_control_out(dev, 0x9a, 0x1312, a); 147 if (!r) 148 r = ch341_control_out(dev, 0x9a, 0x0f2c, b); 149 150 return r; 151} 152 153static int ch341_set_handshake(struct usb_device *dev, u8 control) 154{ 155 dbg("ch341_set_handshake(0x%02x)", control); 156 return ch341_control_out(dev, 0xa4, ~control, 0); 157} 158 159static int ch341_get_status(struct usb_device *dev, struct ch341_private *priv) 160{ 161 char *buffer; 162 int r; 163 const unsigned size = 8; 164 unsigned long flags; 165 166 dbg("ch341_get_status()"); 167 168 buffer = kmalloc(size, GFP_KERNEL); 169 if (!buffer) 170 return -ENOMEM; 171 172 r = ch341_control_in(dev, 0x95, 0x0706, 0, buffer, size); 173 if (r < 0) 174 goto out; 175 176 /* setup the private status if available */ 177 if (r == 2) { 178 r = 0; 179 spin_lock_irqsave(&priv->lock, flags); 180 priv->line_status = (~(*buffer)) & CH341_BITS_MODEM_STAT; 181 priv->multi_status_change = 0; 182 spin_unlock_irqrestore(&priv->lock, flags); 183 } else 184 r = -EPROTO; 185 186out: kfree(buffer); 187 return r; 188} 189 190/* -------------------------------------------------------------------------- */ 191 192static int ch341_configure(struct usb_device *dev, struct ch341_private *priv) 193{ 194 char *buffer; 195 int r; 196 const unsigned size = 8; 197 198 dbg("ch341_configure()"); 199 200 buffer = kmalloc(size, GFP_KERNEL); 201 if (!buffer) 202 return -ENOMEM; 203 204 /* expect two bytes 0x27 0x00 */ 205 r = ch341_control_in(dev, 0x5f, 0, 0, buffer, size); 206 if (r < 0) 207 goto out; 208 209 r = ch341_control_out(dev, 0xa1, 0, 0); 210 if (r < 0) 211 goto out; 212 213 r = ch341_set_baudrate(dev, priv); 214 if (r < 0) 215 goto out; 216 217 /* expect two bytes 0x56 0x00 */ 218 r = ch341_control_in(dev, 0x95, 0x2518, 0, buffer, size); 219 if (r < 0) 220 goto out; 221 222 r = ch341_control_out(dev, 0x9a, 0x2518, 0x0050); 223 if (r < 0) 224 goto out; 225 226 /* expect 0xff 0xee */ 227 r = ch341_get_status(dev, priv); 228 if (r < 0) 229 goto out; 230 231 r = ch341_control_out(dev, 0xa1, 0x501f, 0xd90a); 232 if (r < 0) 233 goto out; 234 235 r = ch341_set_baudrate(dev, priv); 236 if (r < 0) 237 goto out; 238 239 r = ch341_set_handshake(dev, priv->line_control); 240 if (r < 0) 241 goto out; 242 243 /* expect 0x9f 0xee */ 244 r = ch341_get_status(dev, priv); 245 246out: kfree(buffer); 247 return r; 248} 249 250/* allocate private data */ 251static int ch341_attach(struct usb_serial *serial) 252{ 253 struct ch341_private *priv; 254 int r; 255 256 dbg("ch341_attach()"); 257 258 /* private data */ 259 priv = kzalloc(sizeof(struct ch341_private), GFP_KERNEL); 260 if (!priv) 261 return -ENOMEM; 262 263 spin_lock_init(&priv->lock); 264 init_waitqueue_head(&priv->delta_msr_wait); 265 priv->baud_rate = DEFAULT_BAUD_RATE; 266 priv->line_control = CH341_BIT_RTS | CH341_BIT_DTR; 267 268 r = ch341_configure(serial->dev, priv); 269 if (r < 0) 270 goto error; 271 272 usb_set_serial_port_data(serial->port[0], priv); 273 return 0; 274 275error: kfree(priv); 276 return r; 277} 278 279static int ch341_carrier_raised(struct usb_serial_port *port) 280{ 281 struct ch341_private *priv = usb_get_serial_port_data(port); 282 if (priv->line_status & CH341_BIT_DCD) 283 return 1; 284 return 0; 285} 286 287static void ch341_dtr_rts(struct usb_serial_port *port, int on) 288{ 289 struct ch341_private *priv = usb_get_serial_port_data(port); 290 unsigned long flags; 291 292 dbg("%s - port %d", __func__, port->number); 293 /* drop DTR and RTS */ 294 spin_lock_irqsave(&priv->lock, flags); 295 if (on) 296 priv->line_control |= CH341_BIT_RTS | CH341_BIT_DTR; 297 else 298 priv->line_control &= ~(CH341_BIT_RTS | CH341_BIT_DTR); 299 spin_unlock_irqrestore(&priv->lock, flags); 300 ch341_set_handshake(port->serial->dev, priv->line_control); 301 wake_up_interruptible(&priv->delta_msr_wait); 302} 303 304static void ch341_close(struct usb_serial_port *port) 305{ 306 dbg("%s - port %d", __func__, port->number); 307 308 usb_serial_generic_close(port); 309 usb_kill_urb(port->interrupt_in_urb); 310} 311 312 313/* open this device, set default parameters */ 314static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port) 315{ 316 struct usb_serial *serial = port->serial; 317 struct ch341_private *priv = usb_get_serial_port_data(serial->port[0]); 318 int r; 319 320 dbg("ch341_open()"); 321 322 priv->baud_rate = DEFAULT_BAUD_RATE; 323 324 r = ch341_configure(serial->dev, priv); 325 if (r) 326 goto out; 327 328 r = ch341_set_handshake(serial->dev, priv->line_control); 329 if (r) 330 goto out; 331 332 r = ch341_set_baudrate(serial->dev, priv); 333 if (r) 334 goto out; 335 336 dbg("%s - submitting interrupt urb", __func__); 337 port->interrupt_in_urb->dev = serial->dev; 338 r = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL); 339 if (r) { 340 dev_err(&port->dev, "%s - failed submitting interrupt urb," 341 " error %d\n", __func__, r); 342 ch341_close(port); 343 return -EPROTO; 344 } 345 346 r = usb_serial_generic_open(tty, port); 347 348out: return r; 349} 350 351/* Old_termios contains the original termios settings and 352 * tty->termios contains the new setting to be used. 353 */ 354static void ch341_set_termios(struct tty_struct *tty, 355 struct usb_serial_port *port, struct ktermios *old_termios) 356{ 357 struct ch341_private *priv = usb_get_serial_port_data(port); 358 unsigned baud_rate; 359 unsigned long flags; 360 361 dbg("ch341_set_termios()"); 362 363 baud_rate = tty_get_baud_rate(tty); 364 365 priv->baud_rate = baud_rate; 366 367 if (baud_rate) { 368 spin_lock_irqsave(&priv->lock, flags); 369 priv->line_control |= (CH341_BIT_DTR | CH341_BIT_RTS); 370 spin_unlock_irqrestore(&priv->lock, flags); 371 ch341_set_baudrate(port->serial->dev, priv); 372 } else { 373 spin_lock_irqsave(&priv->lock, flags); 374 priv->line_control &= ~(CH341_BIT_DTR | CH341_BIT_RTS); 375 spin_unlock_irqrestore(&priv->lock, flags); 376 } 377 378 ch341_set_handshake(port->serial->dev, priv->line_control); 379 380 /* Unimplemented: 381 * (cflag & CSIZE) : data bits [5, 8] 382 * (cflag & PARENB) : parity {NONE, EVEN, ODD} 383 * (cflag & CSTOPB) : stop bits [1, 2] 384 */ 385} 386 387static void ch341_break_ctl(struct tty_struct *tty, int break_state) 388{ 389 const uint16_t ch341_break_reg = 390 CH341_REG_BREAK1 | ((uint16_t) CH341_REG_BREAK2 << 8); 391 struct usb_serial_port *port = tty->driver_data; 392 int r; 393 uint16_t reg_contents; 394 uint8_t *break_reg; 395 396 dbg("%s()", __func__); 397 398 break_reg = kmalloc(2, GFP_KERNEL); 399 if (!break_reg) { 400 dev_err(&port->dev, "%s - kmalloc failed\n", __func__); 401 return; 402 } 403 404 r = ch341_control_in(port->serial->dev, CH341_REQ_READ_REG, 405 ch341_break_reg, 0, break_reg, 2); 406 if (r < 0) { 407 dev_err(&port->dev, "%s - USB control read error (%d)\n", 408 __func__, r); 409 goto out; 410 } 411 dbg("%s - initial ch341 break register contents - reg1: %x, reg2: %x", 412 __func__, break_reg[0], break_reg[1]); 413 if (break_state != 0) { 414 dbg("%s - Enter break state requested", __func__); 415 break_reg[0] &= ~CH341_NBREAK_BITS_REG1; 416 break_reg[1] &= ~CH341_NBREAK_BITS_REG2; 417 } else { 418 dbg("%s - Leave break state requested", __func__); 419 break_reg[0] |= CH341_NBREAK_BITS_REG1; 420 break_reg[1] |= CH341_NBREAK_BITS_REG2; 421 } 422 dbg("%s - New ch341 break register contents - reg1: %x, reg2: %x", 423 __func__, break_reg[0], break_reg[1]); 424 reg_contents = get_unaligned_le16(break_reg); 425 r = ch341_control_out(port->serial->dev, CH341_REQ_WRITE_REG, 426 ch341_break_reg, reg_contents); 427 if (r < 0) 428 dev_err(&port->dev, "%s - USB control write error (%d)\n", 429 __func__, r); 430out: 431 kfree(break_reg); 432} 433 434static int ch341_tiocmset(struct tty_struct *tty, struct file *file, 435 unsigned int set, unsigned int clear) 436{ 437 struct usb_serial_port *port = tty->driver_data; 438 struct ch341_private *priv = usb_get_serial_port_data(port); 439 unsigned long flags; 440 u8 control; 441 442 spin_lock_irqsave(&priv->lock, flags); 443 if (set & TIOCM_RTS) 444 priv->line_control |= CH341_BIT_RTS; 445 if (set & TIOCM_DTR) 446 priv->line_control |= CH341_BIT_DTR; 447 if (clear & TIOCM_RTS) 448 priv->line_control &= ~CH341_BIT_RTS; 449 if (clear & TIOCM_DTR) 450 priv->line_control &= ~CH341_BIT_DTR; 451 control = priv->line_control; 452 spin_unlock_irqrestore(&priv->lock, flags); 453 454 return ch341_set_handshake(port->serial->dev, control); 455} 456 457static void ch341_read_int_callback(struct urb *urb) 458{ 459 struct usb_serial_port *port = (struct usb_serial_port *) urb->context; 460 unsigned char *data = urb->transfer_buffer; 461 unsigned int actual_length = urb->actual_length; 462 int status; 463 464 dbg("%s (%d)", __func__, port->number); 465 466 switch (urb->status) { 467 case 0: 468 /* success */ 469 break; 470 case -ECONNRESET: 471 case -ENOENT: 472 case -ESHUTDOWN: 473 /* this urb is terminated, clean up */ 474 dbg("%s - urb shutting down with status: %d", __func__, 475 urb->status); 476 return; 477 default: 478 dbg("%s - nonzero urb status received: %d", __func__, 479 urb->status); 480 goto exit; 481 } 482 483 usb_serial_debug_data(debug, &port->dev, __func__, 484 urb->actual_length, urb->transfer_buffer); 485 486 if (actual_length >= 4) { 487 struct ch341_private *priv = usb_get_serial_port_data(port); 488 unsigned long flags; 489 u8 prev_line_status = priv->line_status; 490 491 spin_lock_irqsave(&priv->lock, flags); 492 priv->line_status = (~(data[2])) & CH341_BITS_MODEM_STAT; 493 if ((data[1] & CH341_MULT_STAT)) 494 priv->multi_status_change = 1; 495 spin_unlock_irqrestore(&priv->lock, flags); 496 497 if ((priv->line_status ^ prev_line_status) & CH341_BIT_DCD) { 498 struct tty_struct *tty = tty_port_tty_get(&port->port); 499 if (tty) 500 usb_serial_handle_dcd_change(port, tty, 501 priv->line_status & CH341_BIT_DCD); 502 tty_kref_put(tty); 503 } 504 505 wake_up_interruptible(&priv->delta_msr_wait); 506 } 507 508exit: 509 status = usb_submit_urb(urb, GFP_ATOMIC); 510 if (status) 511 dev_err(&urb->dev->dev, 512 "%s - usb_submit_urb failed with result %d\n", 513 __func__, status); 514} 515 516static int wait_modem_info(struct usb_serial_port *port, unsigned int arg) 517{ 518 struct ch341_private *priv = usb_get_serial_port_data(port); 519 unsigned long flags; 520 u8 prevstatus; 521 u8 status; 522 u8 changed; 523 u8 multi_change = 0; 524 525 spin_lock_irqsave(&priv->lock, flags); 526 prevstatus = priv->line_status; 527 priv->multi_status_change = 0; 528 spin_unlock_irqrestore(&priv->lock, flags); 529 530 while (!multi_change) { 531 interruptible_sleep_on(&priv->delta_msr_wait); 532 /* see if a signal did it */ 533 if (signal_pending(current)) 534 return -ERESTARTSYS; 535 536 spin_lock_irqsave(&priv->lock, flags); 537 status = priv->line_status; 538 multi_change = priv->multi_status_change; 539 spin_unlock_irqrestore(&priv->lock, flags); 540 541 changed = prevstatus ^ status; 542 543 if (((arg & TIOCM_RNG) && (changed & CH341_BIT_RI)) || 544 ((arg & TIOCM_DSR) && (changed & CH341_BIT_DSR)) || 545 ((arg & TIOCM_CD) && (changed & CH341_BIT_DCD)) || 546 ((arg & TIOCM_CTS) && (changed & CH341_BIT_CTS))) { 547 return 0; 548 } 549 prevstatus = status; 550 } 551 552 return 0; 553} 554 555/*static int ch341_ioctl(struct usb_serial_port *port, struct file *file,*/ 556static int ch341_ioctl(struct tty_struct *tty, struct file *file, 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 575static int ch341_tiocmget(struct tty_struct *tty, struct file *file) 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 604static 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 621static 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 633static 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 654static 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 667static void __exit ch341_exit(void) 668{ 669 usb_deregister(&ch341_driver); 670 usb_serial_deregister(&ch341_device); 671} 672 673module_init(ch341_init); 674module_exit(ch341_exit); 675MODULE_LICENSE("GPL"); 676 677module_param(debug, bool, S_IRUGO | S_IWUSR); 678MODULE_PARM_DESC(debug, "Debug enabled or not"); 679 680/* EOF ch341.c */ 681