Loading...
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 | // SPDX-License-Identifier: GPL-2.0+ /* * Copyright (C) 2009 by Bart Hartgers (bart.hartgers+ark3116@gmail.com) * Original version: * Copyright (C) 2006 * Simon Schulz (ark3116_driver <at> auctionant.de) * * ark3116 * - implements a driver for the arkmicro ark3116 chipset (vendor=0x6547, * productid=0x0232) (used in a datacable called KQ-U8A) * * Supports full modem status lines, break, hardware flow control. Does not * support software flow control, since I do not know how to enable it in hw. * * This driver is a essentially new implementation. I initially dug * into the old ark3116.c driver and suddenly realized the ark3116 is * a 16450 with a USB interface glued to it. See comments at the * bottom of this file. */ #include <linux/kernel.h> #include <linux/ioctl.h> #include <linux/tty.h> #include <linux/slab.h> #include <linux/tty_flip.h> #include <linux/module.h> #include <linux/usb.h> #include <linux/usb/serial.h> #include <linux/serial.h> #include <linux/serial_reg.h> #include <linux/uaccess.h> #include <linux/mutex.h> #include <linux/spinlock.h> #define DRIVER_AUTHOR "Bart Hartgers <bart.hartgers+ark3116@gmail.com>" #define DRIVER_DESC "USB ARK3116 serial/IrDA driver" #define DRIVER_DEV_DESC "ARK3116 RS232/IrDA" #define DRIVER_NAME "ark3116" /* usb timeout of 1 second */ #define ARK_TIMEOUT 1000 static const struct usb_device_id id_table[] = { { USB_DEVICE(0x6547, 0x0232) }, { USB_DEVICE(0x18ec, 0x3118) }, /* USB to IrDA adapter */ { }, }; MODULE_DEVICE_TABLE(usb, id_table); static int is_irda(struct usb_serial *serial) { struct usb_device *dev = serial->dev; if (le16_to_cpu(dev->descriptor.idVendor) == 0x18ec && le16_to_cpu(dev->descriptor.idProduct) == 0x3118) return 1; return 0; } struct ark3116_private { int irda; /* 1 for irda device */ /* protects hw register updates */ struct mutex hw_lock; int quot; /* baudrate divisor */ __u32 lcr; /* line control register value */ __u32 hcr; /* handshake control register (0x8) * value */ __u32 mcr; /* modem control register value */ /* protects the status values below */ spinlock_t status_lock; __u32 msr; /* modem status register value */ __u32 lsr; /* line status register value */ }; static int ark3116_write_reg(struct usb_serial *serial, unsigned reg, __u8 val) { int result; /* 0xfe 0x40 are magic values taken from original driver */ result = usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0), 0xfe, 0x40, val, reg, NULL, 0, ARK_TIMEOUT); if (result) return result; return 0; } static int ark3116_read_reg(struct usb_serial *serial, unsigned reg, unsigned char *buf) { int result; /* 0xfe 0xc0 are magic values taken from original driver */ result = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0), 0xfe, 0xc0, 0, reg, buf, 1, ARK_TIMEOUT); if (result < 1) { dev_err(&serial->interface->dev, "failed to read register %u: %d\n", reg, result); if (result >= 0) result = -EIO; return result; } return 0; } static inline int calc_divisor(int bps) { /* Original ark3116 made some exceptions in rounding here * because windows did the same. Assume that is not really * necessary. * Crystal is 12MHz, probably because of USB, but we divide by 4? */ return (12000000 + 2*bps) / (4*bps); } static int ark3116_port_probe(struct usb_serial_port *port) { struct usb_serial *serial = port->serial; struct ark3116_private *priv; priv = kzalloc(sizeof(*priv), GFP_KERNEL); if (!priv) return -ENOMEM; mutex_init(&priv->hw_lock); spin_lock_init(&priv->status_lock); priv->irda = is_irda(serial); usb_set_serial_port_data(port, priv); /* setup the hardware */ ark3116_write_reg(serial, UART_IER, 0); /* disable DMA */ ark3116_write_reg(serial, UART_FCR, 0); /* handshake control */ priv->hcr = 0; ark3116_write_reg(serial, 0x8 , 0); /* modem control */ priv->mcr = 0; ark3116_write_reg(serial, UART_MCR, 0); if (!(priv->irda)) { ark3116_write_reg(serial, 0xb , 0); } else { ark3116_write_reg(serial, 0xb , 1); ark3116_write_reg(serial, 0xc , 0); ark3116_write_reg(serial, 0xd , 0x41); ark3116_write_reg(serial, 0xa , 1); } /* setup baudrate */ ark3116_write_reg(serial, UART_LCR, UART_LCR_DLAB); /* setup for 9600 8N1 */ priv->quot = calc_divisor(9600); ark3116_write_reg(serial, UART_DLL, priv->quot & 0xff); ark3116_write_reg(serial, UART_DLM, (priv->quot>>8) & 0xff); priv->lcr = UART_LCR_WLEN8; ark3116_write_reg(serial, UART_LCR, UART_LCR_WLEN8); ark3116_write_reg(serial, 0xe, 0); if (priv->irda) ark3116_write_reg(serial, 0x9, 0); dev_info(&port->dev, "using %s mode\n", priv->irda ? "IrDA" : "RS232"); return 0; } static void ark3116_port_remove(struct usb_serial_port *port) { struct ark3116_private *priv = usb_get_serial_port_data(port); /* device is closed, so URBs and DMA should be down */ mutex_destroy(&priv->hw_lock); kfree(priv); } static void ark3116_set_termios(struct tty_struct *tty, struct usb_serial_port *port, const struct ktermios *old_termios) { struct usb_serial *serial = port->serial; struct ark3116_private *priv = usb_get_serial_port_data(port); struct ktermios *termios = &tty->termios; unsigned int cflag = termios->c_cflag; int bps = tty_get_baud_rate(tty); int quot; __u8 lcr, hcr, eval; /* set data bit count */ lcr = UART_LCR_WLEN(tty_get_char_size(cflag)); if (cflag & CSTOPB) lcr |= UART_LCR_STOP; if (cflag & PARENB) lcr |= UART_LCR_PARITY; if (!(cflag & PARODD)) lcr |= UART_LCR_EPAR; if (cflag & CMSPAR) lcr |= UART_LCR_SPAR; /* handshake control */ hcr = (cflag & CRTSCTS) ? 0x03 : 0x00; /* calc baudrate */ dev_dbg(&port->dev, "%s - setting bps to %d\n", __func__, bps); eval = 0; switch (bps) { case 0: quot = calc_divisor(9600); break; default: if ((bps < 75) || (bps > 3000000)) bps = 9600; quot = calc_divisor(bps); break; case 460800: eval = 1; quot = calc_divisor(bps); break; case 921600: eval = 2; quot = calc_divisor(bps); break; } /* Update state: synchronize */ mutex_lock(&priv->hw_lock); /* keep old LCR_SBC bit */ lcr |= (priv->lcr & UART_LCR_SBC); dev_dbg(&port->dev, "%s - setting hcr:0x%02x,lcr:0x%02x,quot:%d\n", __func__, hcr, lcr, quot); /* handshake control */ if (priv->hcr != hcr) { priv->hcr = hcr; ark3116_write_reg(serial, 0x8, hcr); } /* baudrate */ if (priv->quot != quot) { priv->quot = quot; priv->lcr = lcr; /* need to write lcr anyway */ /* disable DMA since transmit/receive is * shadowed by UART_DLL */ ark3116_write_reg(serial, UART_FCR, 0); ark3116_write_reg(serial, UART_LCR, lcr|UART_LCR_DLAB); ark3116_write_reg(serial, UART_DLL, quot & 0xff); ark3116_write_reg(serial, UART_DLM, (quot>>8) & 0xff); /* restore lcr */ ark3116_write_reg(serial, UART_LCR, lcr); /* magic baudrate thingy: not sure what it does, * but windows does this as well. */ ark3116_write_reg(serial, 0xe, eval); /* enable DMA */ ark3116_write_reg(serial, UART_FCR, UART_FCR_DMA_SELECT); } else if (priv->lcr != lcr) { priv->lcr = lcr; ark3116_write_reg(serial, UART_LCR, lcr); } mutex_unlock(&priv->hw_lock); /* check for software flow control */ if (I_IXOFF(tty) || I_IXON(tty)) { dev_warn(&port->dev, "software flow control not implemented\n"); } /* Don't rewrite B0 */ if (tty_termios_baud_rate(termios)) tty_termios_encode_baud_rate(termios, bps, bps); } static void ark3116_close(struct usb_serial_port *port) { struct usb_serial *serial = port->serial; /* disable DMA */ ark3116_write_reg(serial, UART_FCR, 0); /* deactivate interrupts */ ark3116_write_reg(serial, UART_IER, 0); usb_serial_generic_close(port); usb_kill_urb(port->interrupt_in_urb); } static int ark3116_open(struct tty_struct *tty, struct usb_serial_port *port) { struct ark3116_private *priv = usb_get_serial_port_data(port); struct usb_serial *serial = port->serial; unsigned char *buf; int result; buf = kmalloc(1, GFP_KERNEL); if (buf == NULL) return -ENOMEM; result = usb_serial_generic_open(tty, port); if (result) { dev_dbg(&port->dev, "%s - usb_serial_generic_open failed: %d\n", __func__, result); goto err_free; } /* remove any data still left: also clears error state */ ark3116_read_reg(serial, UART_RX, buf); /* read modem status */ result = ark3116_read_reg(serial, UART_MSR, buf); if (result) goto err_close; priv->msr = *buf; /* read line status */ result = ark3116_read_reg(serial, UART_LSR, buf); if (result) goto err_close; priv->lsr = *buf; result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL); if (result) { dev_err(&port->dev, "submit irq_in urb failed %d\n", result); goto err_close; } /* activate interrupts */ ark3116_write_reg(port->serial, UART_IER, UART_IER_MSI|UART_IER_RLSI); /* enable DMA */ ark3116_write_reg(port->serial, UART_FCR, UART_FCR_DMA_SELECT); /* setup termios */ if (tty) ark3116_set_termios(tty, port, NULL); kfree(buf); return 0; err_close: usb_serial_generic_close(port); err_free: kfree(buf); return result; } static int ark3116_tiocmget(struct tty_struct *tty) { struct usb_serial_port *port = tty->driver_data; struct ark3116_private *priv = usb_get_serial_port_data(port); __u32 status; __u32 ctrl; unsigned long flags; mutex_lock(&priv->hw_lock); ctrl = priv->mcr; mutex_unlock(&priv->hw_lock); spin_lock_irqsave(&priv->status_lock, flags); status = priv->msr; spin_unlock_irqrestore(&priv->status_lock, flags); return (status & UART_MSR_DSR ? TIOCM_DSR : 0) | (status & UART_MSR_CTS ? TIOCM_CTS : 0) | (status & UART_MSR_RI ? TIOCM_RI : 0) | (status & UART_MSR_DCD ? TIOCM_CD : 0) | (ctrl & UART_MCR_DTR ? TIOCM_DTR : 0) | (ctrl & UART_MCR_RTS ? TIOCM_RTS : 0) | (ctrl & UART_MCR_OUT1 ? TIOCM_OUT1 : 0) | (ctrl & UART_MCR_OUT2 ? TIOCM_OUT2 : 0); } static int ark3116_tiocmset(struct tty_struct *tty, unsigned set, unsigned clr) { struct usb_serial_port *port = tty->driver_data; struct ark3116_private *priv = usb_get_serial_port_data(port); /* we need to take the mutex here, to make sure that the value * in priv->mcr is actually the one that is in the hardware */ mutex_lock(&priv->hw_lock); if (set & TIOCM_RTS) priv->mcr |= UART_MCR_RTS; if (set & TIOCM_DTR) priv->mcr |= UART_MCR_DTR; if (set & TIOCM_OUT1) priv->mcr |= UART_MCR_OUT1; if (set & TIOCM_OUT2) priv->mcr |= UART_MCR_OUT2; if (clr & TIOCM_RTS) priv->mcr &= ~UART_MCR_RTS; if (clr & TIOCM_DTR) priv->mcr &= ~UART_MCR_DTR; if (clr & TIOCM_OUT1) priv->mcr &= ~UART_MCR_OUT1; if (clr & TIOCM_OUT2) priv->mcr &= ~UART_MCR_OUT2; ark3116_write_reg(port->serial, UART_MCR, priv->mcr); mutex_unlock(&priv->hw_lock); return 0; } static int ark3116_break_ctl(struct tty_struct *tty, int break_state) { struct usb_serial_port *port = tty->driver_data; struct ark3116_private *priv = usb_get_serial_port_data(port); int ret; /* LCR is also used for other things: protect access */ mutex_lock(&priv->hw_lock); if (break_state) priv->lcr |= UART_LCR_SBC; else priv->lcr &= ~UART_LCR_SBC; ret = ark3116_write_reg(port->serial, UART_LCR, priv->lcr); mutex_unlock(&priv->hw_lock); return ret; } static void ark3116_update_msr(struct usb_serial_port *port, __u8 msr) { struct ark3116_private *priv = usb_get_serial_port_data(port); unsigned long flags; spin_lock_irqsave(&priv->status_lock, flags); priv->msr = msr; spin_unlock_irqrestore(&priv->status_lock, flags); if (msr & UART_MSR_ANY_DELTA) { /* update input line counters */ if (msr & UART_MSR_DCTS) port->icount.cts++; if (msr & UART_MSR_DDSR) port->icount.dsr++; if (msr & UART_MSR_DDCD) port->icount.dcd++; if (msr & UART_MSR_TERI) port->icount.rng++; wake_up_interruptible(&port->port.delta_msr_wait); } } static void ark3116_update_lsr(struct usb_serial_port *port, __u8 lsr) { struct ark3116_private *priv = usb_get_serial_port_data(port); unsigned long flags; spin_lock_irqsave(&priv->status_lock, flags); /* combine bits */ priv->lsr |= lsr; spin_unlock_irqrestore(&priv->status_lock, flags); if (lsr&UART_LSR_BRK_ERROR_BITS) { if (lsr & UART_LSR_BI) port->icount.brk++; if (lsr & UART_LSR_FE) port->icount.frame++; if (lsr & UART_LSR_PE) port->icount.parity++; if (lsr & UART_LSR_OE) port->icount.overrun++; } } static void ark3116_read_int_callback(struct urb *urb) { struct usb_serial_port *port = urb->context; int status = urb->status; const __u8 *data = urb->transfer_buffer; int result; switch (status) { case -ECONNRESET: case -ENOENT: case -ESHUTDOWN: /* this urb is terminated, clean up */ dev_dbg(&port->dev, "%s - urb shutting down with status: %d\n", __func__, status); return; default: dev_dbg(&port->dev, "%s - nonzero urb status received: %d\n", __func__, status); break; case 0: /* success */ /* discovered this by trail and error... */ if ((urb->actual_length == 4) && (data[0] == 0xe8)) { const __u8 id = data[1]&UART_IIR_ID; dev_dbg(&port->dev, "%s: iir=%02x\n", __func__, data[1]); if (id == UART_IIR_MSI) { dev_dbg(&port->dev, "%s: msr=%02x\n", __func__, data[3]); ark3116_update_msr(port, data[3]); break; } else if (id == UART_IIR_RLSI) { dev_dbg(&port->dev, "%s: lsr=%02x\n", __func__, data[2]); ark3116_update_lsr(port, data[2]); break; } } /* * Not sure what this data meant... */ usb_serial_debug_data(&port->dev, __func__, urb->actual_length, urb->transfer_buffer); break; } result = usb_submit_urb(urb, GFP_ATOMIC); if (result) dev_err(&port->dev, "failed to resubmit interrupt urb: %d\n", result); } /* Data comes in via the bulk (data) URB, errors/interrupts via the int URB. * This means that we cannot be sure which data byte has an associated error * condition, so we report an error for all data in the next bulk read. * * Actually, there might even be a window between the bulk data leaving the * ark and reading/resetting the lsr in the read_bulk_callback where an * interrupt for the next data block could come in. * Without somekind of ordering on the ark, we would have to report the * error for the next block of data as well... * For now, let's pretend this can't happen. */ static void ark3116_process_read_urb(struct urb *urb) { struct usb_serial_port *port = urb->context; struct ark3116_private *priv = usb_get_serial_port_data(port); unsigned char *data = urb->transfer_buffer; char tty_flag = TTY_NORMAL; unsigned long flags; __u32 lsr; /* update line status */ spin_lock_irqsave(&priv->status_lock, flags); lsr = priv->lsr; priv->lsr &= ~UART_LSR_BRK_ERROR_BITS; spin_unlock_irqrestore(&priv->status_lock, flags); if (!urb->actual_length) return; if (lsr & UART_LSR_BRK_ERROR_BITS) { if (lsr & UART_LSR_BI) tty_flag = TTY_BREAK; else if (lsr & UART_LSR_PE) tty_flag = TTY_PARITY; else if (lsr & UART_LSR_FE) tty_flag = TTY_FRAME; /* overrun is special, not associated with a char */ if (lsr & UART_LSR_OE) tty_insert_flip_char(&port->port, 0, TTY_OVERRUN); } tty_insert_flip_string_fixed_flag(&port->port, data, tty_flag, urb->actual_length); tty_flip_buffer_push(&port->port); } static struct usb_serial_driver ark3116_device = { .driver = { .owner = THIS_MODULE, .name = "ark3116", }, .id_table = id_table, .num_ports = 1, .num_bulk_in = 1, .num_bulk_out = 1, .num_interrupt_in = 1, .port_probe = ark3116_port_probe, .port_remove = ark3116_port_remove, .set_termios = ark3116_set_termios, .tiocmget = ark3116_tiocmget, .tiocmset = ark3116_tiocmset, .tiocmiwait = usb_serial_generic_tiocmiwait, .get_icount = usb_serial_generic_get_icount, .open = ark3116_open, .close = ark3116_close, .break_ctl = ark3116_break_ctl, .read_int_callback = ark3116_read_int_callback, .process_read_urb = ark3116_process_read_urb, }; static struct usb_serial_driver * const serial_drivers[] = { &ark3116_device, NULL }; module_usb_serial_driver(serial_drivers, id_table); MODULE_LICENSE("GPL"); MODULE_AUTHOR(DRIVER_AUTHOR); MODULE_DESCRIPTION(DRIVER_DESC); /* * The following describes what I learned from studying the old * ark3116.c driver, disassembling the windows driver, and some lucky * guesses. Since I do not have any datasheet or other * documentation, inaccuracies are almost guaranteed. * * Some specs for the ARK3116 can be found here: * http://web.archive.org/web/20060318000438/ * www.arkmicro.com/en/products/view.php?id=10 * On that page, 2 GPIO pins are mentioned: I assume these are the * OUT1 and OUT2 pins of the UART, so I added support for those * through the MCR. Since the pins are not available on my hardware, * I could not verify this. * Also, it states there is "on-chip hardware flow control". I have * discovered how to enable that. Unfortunately, I do not know how to * enable XON/XOFF (software) flow control, which would need support * from the chip as well to work. Because of the wording on the web * page there is a real possibility the chip simply does not support * software flow control. * * I got my ark3116 as part of a mobile phone adapter cable. On the * PCB, the following numbered contacts are present: * * 1:- +5V * 2:o DTR * 3:i RX * 4:i DCD * 5:o RTS * 6:o TX * 7:i RI * 8:i DSR * 10:- 0V * 11:i CTS * * On my chip, all signals seem to be 3.3V, but 5V tolerant. But that * may be different for the one you have ;-). * * The windows driver limits the registers to 0-F, so I assume there * are actually 16 present on the device. * * On an UART interrupt, 4 bytes of data come in on the interrupt * endpoint. The bytes are 0xe8 IIR LSR MSR. * * The baudrate seems to be generated from the 12MHz crystal, using * 4-times subsampling. So quot=12e6/(4*baud). Also see description * of register E. * * Registers 0-7: * These seem to be the same as for a regular 16450. The FCR is set * to UART_FCR_DMA_SELECT (0x8), I guess to enable transfers between * the UART and the USB bridge/DMA engine. * * Register 8: * By trial and error, I found out that bit 0 enables hardware CTS, * stopping TX when CTS is +5V. Bit 1 does the same for RTS, making * RTS +5V when the 3116 cannot transfer the data to the USB bus * (verified by disabling the reading URB). Note that as far as I can * tell, the windows driver does NOT use this, so there might be some * hardware bug or something. * * According to a patch provided here * https://lore.kernel.org/lkml/200907261419.50702.linux@rainbow-software.org * the ARK3116 can also be used as an IrDA dongle. Since I do not have * such a thing, I could not investigate that aspect. However, I can * speculate ;-). * * - IrDA encodes data differently than RS232. Most likely, one of * the bits in registers 9..E enables the IR ENDEC (encoder/decoder). * - Depending on the IR transceiver, the input and output need to be * inverted, so there are probably bits for that as well. * - IrDA is half-duplex, so there should be a bit for selecting that. * * This still leaves at least two registers unaccounted for. Perhaps * The chip can do XON/XOFF or CRC in HW? * * Register 9: * Set to 0x00 for IrDA, when the baudrate is initialised. * * Register A: * Set to 0x01 for IrDA, at init. * * Register B: * Set to 0x01 for IrDA, 0x00 for RS232, at init. * * Register C: * Set to 00 for IrDA, at init. * * Register D: * Set to 0x41 for IrDA, at init. * * Register E: * Somekind of baudrate override. The windows driver seems to set * this to 0x00 for normal baudrates, 0x01 for 460800, 0x02 for 921600. * Since 460800 and 921600 cannot be obtained by dividing 3MHz by an integer, * it could be somekind of subdivisor thingy. * However,it does not seem to do anything: selecting 921600 (divisor 3, * reg E=2), still gets 1 MHz. I also checked if registers 9, C or F would * work, but they don't. * * Register F: unknown */ |