1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright 2007, Frank A Kingswood <frank@kingswood-consulting.co.uk> 4 * Copyright 2007, Werner Cornelius <werner@cornelius-consult.de> 5 * Copyright 2009, Boris Hajduk <boris@hajduk.org> 6 * 7 * ch341.c implements a serial port driver for the Winchiphead CH341. 8 * 9 * The CH341 device can be used to implement an RS232 asynchronous 10 * serial port, an IEEE-1284 parallel printer port or a memory-like 11 * interface. In all cases the CH341 supports an I2C interface as well. 12 * This driver only supports the asynchronous serial interface. 13 */ 14 15 #include <linux/kernel.h> 16 #include <linux/tty.h> 17 #include <linux/module.h> 18 #include <linux/slab.h> 19 #include <linux/usb.h> 20 #include <linux/usb/serial.h> 21 #include <linux/serial.h> 22 #include <asm/unaligned.h> 23 24 #define DEFAULT_BAUD_RATE 9600 25 #define DEFAULT_TIMEOUT 1000 26 27 /* flags for IO-Bits */ 28 #define CH341_BIT_RTS (1 << 6) 29 #define CH341_BIT_DTR (1 << 5) 30 31 /******************************/ 32 /* interrupt pipe definitions */ 33 /******************************/ 34 /* always 4 interrupt bytes */ 35 /* first irq byte normally 0x08 */ 36 /* second irq byte base 0x7d + below */ 37 /* third irq byte base 0x94 + below */ 38 /* fourth irq byte normally 0xee */ 39 40 /* second interrupt byte */ 41 #define CH341_MULT_STAT 0x04 /* multiple status since last interrupt event */ 42 43 /* status returned in third interrupt answer byte, inverted in data 44 from irq */ 45 #define CH341_BIT_CTS 0x01 46 #define CH341_BIT_DSR 0x02 47 #define CH341_BIT_RI 0x04 48 #define CH341_BIT_DCD 0x08 49 #define CH341_BITS_MODEM_STAT 0x0f /* all bits */ 50 51 /* Break support - the information used to implement this was gleaned from 52 * the Net/FreeBSD uchcom.c driver by Takanori Watanabe. Domo arigato. 53 */ 54 55 #define CH341_REQ_READ_VERSION 0x5F 56 #define CH341_REQ_WRITE_REG 0x9A 57 #define CH341_REQ_READ_REG 0x95 58 #define CH341_REQ_SERIAL_INIT 0xA1 59 #define CH341_REQ_MODEM_CTRL 0xA4 60 61 #define CH341_REG_BREAK 0x05 62 #define CH341_REG_PRESCALER 0x12 63 #define CH341_REG_DIVISOR 0x13 64 #define CH341_REG_LCR 0x18 65 #define CH341_REG_LCR2 0x25 66 67 #define CH341_NBREAK_BITS 0x01 68 69 #define CH341_LCR_ENABLE_RX 0x80 70 #define CH341_LCR_ENABLE_TX 0x40 71 #define CH341_LCR_MARK_SPACE 0x20 72 #define CH341_LCR_PAR_EVEN 0x10 73 #define CH341_LCR_ENABLE_PAR 0x08 74 #define CH341_LCR_STOP_BITS_2 0x04 75 #define CH341_LCR_CS8 0x03 76 #define CH341_LCR_CS7 0x02 77 #define CH341_LCR_CS6 0x01 78 #define CH341_LCR_CS5 0x00 79 80 #define CH341_QUIRK_LIMITED_PRESCALER BIT(0) 81 #define CH341_QUIRK_SIMULATE_BREAK BIT(1) 82 83 static const struct usb_device_id id_table[] = { 84 { USB_DEVICE(0x1a86, 0x5512) }, 85 { USB_DEVICE(0x1a86, 0x5523) }, 86 { USB_DEVICE(0x1a86, 0x7522) }, 87 { USB_DEVICE(0x1a86, 0x7523) }, 88 { USB_DEVICE(0x4348, 0x5523) }, 89 { }, 90 }; 91 MODULE_DEVICE_TABLE(usb, id_table); 92 93 struct ch341_private { 94 spinlock_t lock; /* access lock */ 95 unsigned baud_rate; /* set baud rate */ 96 u8 mcr; 97 u8 msr; 98 u8 lcr; 99 unsigned long quirks; 100 unsigned long break_end; 101 }; 102 103 static void ch341_set_termios(struct tty_struct *tty, 104 struct usb_serial_port *port, 105 struct ktermios *old_termios); 106 107 static int ch341_control_out(struct usb_device *dev, u8 request, 108 u16 value, u16 index) 109 { 110 int r; 111 112 dev_dbg(&dev->dev, "%s - (%02x,%04x,%04x)\n", __func__, 113 request, value, index); 114 115 r = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), request, 116 USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT, 117 value, index, NULL, 0, DEFAULT_TIMEOUT); 118 if (r < 0) 119 dev_err(&dev->dev, "failed to send control message: %d\n", r); 120 121 return r; 122 } 123 124 static int ch341_control_in(struct usb_device *dev, 125 u8 request, u16 value, u16 index, 126 char *buf, unsigned bufsize) 127 { 128 int r; 129 130 dev_dbg(&dev->dev, "%s - (%02x,%04x,%04x,%u)\n", __func__, 131 request, value, index, bufsize); 132 133 r = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), request, 134 USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN, 135 value, index, buf, bufsize, DEFAULT_TIMEOUT); 136 if (r < (int)bufsize) { 137 if (r >= 0) { 138 dev_err(&dev->dev, 139 "short control message received (%d < %u)\n", 140 r, bufsize); 141 r = -EIO; 142 } 143 144 dev_err(&dev->dev, "failed to receive control message: %d\n", 145 r); 146 return r; 147 } 148 149 return 0; 150 } 151 152 #define CH341_CLKRATE 48000000 153 #define CH341_CLK_DIV(ps, fact) (1 << (12 - 3 * (ps) - (fact))) 154 #define CH341_MIN_RATE(ps) (CH341_CLKRATE / (CH341_CLK_DIV((ps), 1) * 512)) 155 156 static const speed_t ch341_min_rates[] = { 157 CH341_MIN_RATE(0), 158 CH341_MIN_RATE(1), 159 CH341_MIN_RATE(2), 160 CH341_MIN_RATE(3), 161 }; 162 163 /* Supported range is 46 to 3000000 bps. */ 164 #define CH341_MIN_BPS DIV_ROUND_UP(CH341_CLKRATE, CH341_CLK_DIV(0, 0) * 256) 165 #define CH341_MAX_BPS (CH341_CLKRATE / (CH341_CLK_DIV(3, 0) * 2)) 166 167 /* 168 * The device line speed is given by the following equation: 169 * 170 * baudrate = 48000000 / (2^(12 - 3 * ps - fact) * div), where 171 * 172 * 0 <= ps <= 3, 173 * 0 <= fact <= 1, 174 * 2 <= div <= 256 if fact = 0, or 175 * 9 <= div <= 256 if fact = 1 176 */ 177 static int ch341_get_divisor(struct ch341_private *priv, speed_t speed) 178 { 179 unsigned int fact, div, clk_div; 180 bool force_fact0 = false; 181 int ps; 182 183 /* 184 * Clamp to supported range, this makes the (ps < 0) and (div < 2) 185 * sanity checks below redundant. 186 */ 187 speed = clamp_val(speed, CH341_MIN_BPS, CH341_MAX_BPS); 188 189 /* 190 * Start with highest possible base clock (fact = 1) that will give a 191 * divisor strictly less than 512. 192 */ 193 fact = 1; 194 for (ps = 3; ps >= 0; ps--) { 195 if (speed > ch341_min_rates[ps]) 196 break; 197 } 198 199 if (ps < 0) 200 return -EINVAL; 201 202 /* Determine corresponding divisor, rounding down. */ 203 clk_div = CH341_CLK_DIV(ps, fact); 204 div = CH341_CLKRATE / (clk_div * speed); 205 206 /* Some devices require a lower base clock if ps < 3. */ 207 if (ps < 3 && (priv->quirks & CH341_QUIRK_LIMITED_PRESCALER)) 208 force_fact0 = true; 209 210 /* Halve base clock (fact = 0) if required. */ 211 if (div < 9 || div > 255 || force_fact0) { 212 div /= 2; 213 clk_div *= 2; 214 fact = 0; 215 } 216 217 if (div < 2) 218 return -EINVAL; 219 220 /* 221 * Pick next divisor if resulting rate is closer to the requested one, 222 * scale up to avoid rounding errors on low rates. 223 */ 224 if (16 * CH341_CLKRATE / (clk_div * div) - 16 * speed >= 225 16 * speed - 16 * CH341_CLKRATE / (clk_div * (div + 1))) 226 div++; 227 228 /* 229 * Prefer lower base clock (fact = 0) if even divisor. 230 * 231 * Note that this makes the receiver more tolerant to errors. 232 */ 233 if (fact == 1 && div % 2 == 0) { 234 div /= 2; 235 fact = 0; 236 } 237 238 return (0x100 - div) << 8 | fact << 2 | ps; 239 } 240 241 static int ch341_set_baudrate_lcr(struct usb_device *dev, 242 struct ch341_private *priv, 243 speed_t baud_rate, u8 lcr) 244 { 245 int val; 246 int r; 247 248 if (!baud_rate) 249 return -EINVAL; 250 251 val = ch341_get_divisor(priv, baud_rate); 252 if (val < 0) 253 return -EINVAL; 254 255 /* 256 * CH341A buffers data until a full endpoint-size packet (32 bytes) 257 * has been received unless bit 7 is set. 258 */ 259 val |= BIT(7); 260 261 r = ch341_control_out(dev, CH341_REQ_WRITE_REG, 262 CH341_REG_DIVISOR << 8 | CH341_REG_PRESCALER, 263 val); 264 if (r) 265 return r; 266 267 /* 268 * Chip versions before version 0x30 as read using 269 * CH341_REQ_READ_VERSION used separate registers for line control 270 * (stop bits, parity and word length). Version 0x30 and above use 271 * CH341_REG_LCR only and CH341_REG_LCR2 is always set to zero. 272 */ 273 r = ch341_control_out(dev, CH341_REQ_WRITE_REG, 274 CH341_REG_LCR2 << 8 | CH341_REG_LCR, lcr); 275 if (r) 276 return r; 277 278 return r; 279 } 280 281 static int ch341_set_handshake(struct usb_device *dev, u8 control) 282 { 283 return ch341_control_out(dev, CH341_REQ_MODEM_CTRL, ~control, 0); 284 } 285 286 static int ch341_get_status(struct usb_device *dev, struct ch341_private *priv) 287 { 288 const unsigned int size = 2; 289 char *buffer; 290 int r; 291 unsigned long flags; 292 293 buffer = kmalloc(size, GFP_KERNEL); 294 if (!buffer) 295 return -ENOMEM; 296 297 r = ch341_control_in(dev, CH341_REQ_READ_REG, 0x0706, 0, buffer, size); 298 if (r < 0) 299 goto out; 300 301 spin_lock_irqsave(&priv->lock, flags); 302 priv->msr = (~(*buffer)) & CH341_BITS_MODEM_STAT; 303 spin_unlock_irqrestore(&priv->lock, flags); 304 305 out: kfree(buffer); 306 return r; 307 } 308 309 /* -------------------------------------------------------------------------- */ 310 311 static int ch341_configure(struct usb_device *dev, struct ch341_private *priv) 312 { 313 const unsigned int size = 2; 314 char *buffer; 315 int r; 316 317 buffer = kmalloc(size, GFP_KERNEL); 318 if (!buffer) 319 return -ENOMEM; 320 321 /* expect two bytes 0x27 0x00 */ 322 r = ch341_control_in(dev, CH341_REQ_READ_VERSION, 0, 0, buffer, size); 323 if (r < 0) 324 goto out; 325 dev_dbg(&dev->dev, "Chip version: 0x%02x\n", buffer[0]); 326 327 r = ch341_control_out(dev, CH341_REQ_SERIAL_INIT, 0, 0); 328 if (r < 0) 329 goto out; 330 331 r = ch341_set_baudrate_lcr(dev, priv, priv->baud_rate, priv->lcr); 332 if (r < 0) 333 goto out; 334 335 r = ch341_set_handshake(dev, priv->mcr); 336 337 out: kfree(buffer); 338 return r; 339 } 340 341 static int ch341_detect_quirks(struct usb_serial_port *port) 342 { 343 struct ch341_private *priv = usb_get_serial_port_data(port); 344 struct usb_device *udev = port->serial->dev; 345 const unsigned int size = 2; 346 unsigned long quirks = 0; 347 char *buffer; 348 int r; 349 350 buffer = kmalloc(size, GFP_KERNEL); 351 if (!buffer) 352 return -ENOMEM; 353 354 /* 355 * A subset of CH34x devices does not support all features. The 356 * prescaler is limited and there is no support for sending a RS232 357 * break condition. A read failure when trying to set up the latter is 358 * used to detect these devices. 359 */ 360 r = usb_control_msg(udev, usb_rcvctrlpipe(udev, 0), CH341_REQ_READ_REG, 361 USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN, 362 CH341_REG_BREAK, 0, buffer, size, DEFAULT_TIMEOUT); 363 if (r == -EPIPE) { 364 dev_info(&port->dev, "break control not supported, using simulated break\n"); 365 quirks = CH341_QUIRK_LIMITED_PRESCALER | CH341_QUIRK_SIMULATE_BREAK; 366 r = 0; 367 goto out; 368 } 369 370 if (r != size) { 371 if (r >= 0) 372 r = -EIO; 373 dev_err(&port->dev, "failed to read break control: %d\n", r); 374 goto out; 375 } 376 377 r = 0; 378 out: 379 kfree(buffer); 380 381 if (quirks) { 382 dev_dbg(&port->dev, "enabling quirk flags: 0x%02lx\n", quirks); 383 priv->quirks |= quirks; 384 } 385 386 return r; 387 } 388 389 static int ch341_port_probe(struct usb_serial_port *port) 390 { 391 struct ch341_private *priv; 392 int r; 393 394 priv = kzalloc(sizeof(struct ch341_private), GFP_KERNEL); 395 if (!priv) 396 return -ENOMEM; 397 398 spin_lock_init(&priv->lock); 399 priv->baud_rate = DEFAULT_BAUD_RATE; 400 /* 401 * Some CH340 devices appear unable to change the initial LCR 402 * settings, so set a sane 8N1 default. 403 */ 404 priv->lcr = CH341_LCR_ENABLE_RX | CH341_LCR_ENABLE_TX | CH341_LCR_CS8; 405 406 r = ch341_configure(port->serial->dev, priv); 407 if (r < 0) 408 goto error; 409 410 usb_set_serial_port_data(port, priv); 411 412 r = ch341_detect_quirks(port); 413 if (r < 0) 414 goto error; 415 416 return 0; 417 418 error: kfree(priv); 419 return r; 420 } 421 422 static int ch341_port_remove(struct usb_serial_port *port) 423 { 424 struct ch341_private *priv; 425 426 priv = usb_get_serial_port_data(port); 427 kfree(priv); 428 429 return 0; 430 } 431 432 static int ch341_carrier_raised(struct usb_serial_port *port) 433 { 434 struct ch341_private *priv = usb_get_serial_port_data(port); 435 if (priv->msr & CH341_BIT_DCD) 436 return 1; 437 return 0; 438 } 439 440 static void ch341_dtr_rts(struct usb_serial_port *port, int on) 441 { 442 struct ch341_private *priv = usb_get_serial_port_data(port); 443 unsigned long flags; 444 445 /* drop DTR and RTS */ 446 spin_lock_irqsave(&priv->lock, flags); 447 if (on) 448 priv->mcr |= CH341_BIT_RTS | CH341_BIT_DTR; 449 else 450 priv->mcr &= ~(CH341_BIT_RTS | CH341_BIT_DTR); 451 spin_unlock_irqrestore(&priv->lock, flags); 452 ch341_set_handshake(port->serial->dev, priv->mcr); 453 } 454 455 static void ch341_close(struct usb_serial_port *port) 456 { 457 usb_serial_generic_close(port); 458 usb_kill_urb(port->interrupt_in_urb); 459 } 460 461 462 /* open this device, set default parameters */ 463 static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port) 464 { 465 struct ch341_private *priv = usb_get_serial_port_data(port); 466 int r; 467 468 if (tty) 469 ch341_set_termios(tty, port, NULL); 470 471 dev_dbg(&port->dev, "%s - submitting interrupt urb\n", __func__); 472 r = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL); 473 if (r) { 474 dev_err(&port->dev, "%s - failed to submit interrupt urb: %d\n", 475 __func__, r); 476 return r; 477 } 478 479 r = ch341_get_status(port->serial->dev, priv); 480 if (r < 0) { 481 dev_err(&port->dev, "failed to read modem status: %d\n", r); 482 goto err_kill_interrupt_urb; 483 } 484 485 r = usb_serial_generic_open(tty, port); 486 if (r) 487 goto err_kill_interrupt_urb; 488 489 return 0; 490 491 err_kill_interrupt_urb: 492 usb_kill_urb(port->interrupt_in_urb); 493 494 return r; 495 } 496 497 /* Old_termios contains the original termios settings and 498 * tty->termios contains the new setting to be used. 499 */ 500 static void ch341_set_termios(struct tty_struct *tty, 501 struct usb_serial_port *port, struct ktermios *old_termios) 502 { 503 struct ch341_private *priv = usb_get_serial_port_data(port); 504 unsigned baud_rate; 505 unsigned long flags; 506 u8 lcr; 507 int r; 508 509 /* redundant changes may cause the chip to lose bytes */ 510 if (old_termios && !tty_termios_hw_change(&tty->termios, old_termios)) 511 return; 512 513 baud_rate = tty_get_baud_rate(tty); 514 515 lcr = CH341_LCR_ENABLE_RX | CH341_LCR_ENABLE_TX; 516 517 switch (C_CSIZE(tty)) { 518 case CS5: 519 lcr |= CH341_LCR_CS5; 520 break; 521 case CS6: 522 lcr |= CH341_LCR_CS6; 523 break; 524 case CS7: 525 lcr |= CH341_LCR_CS7; 526 break; 527 case CS8: 528 lcr |= CH341_LCR_CS8; 529 break; 530 } 531 532 if (C_PARENB(tty)) { 533 lcr |= CH341_LCR_ENABLE_PAR; 534 if (C_PARODD(tty) == 0) 535 lcr |= CH341_LCR_PAR_EVEN; 536 if (C_CMSPAR(tty)) 537 lcr |= CH341_LCR_MARK_SPACE; 538 } 539 540 if (C_CSTOPB(tty)) 541 lcr |= CH341_LCR_STOP_BITS_2; 542 543 if (baud_rate) { 544 priv->baud_rate = baud_rate; 545 546 r = ch341_set_baudrate_lcr(port->serial->dev, priv, 547 priv->baud_rate, lcr); 548 if (r < 0 && old_termios) { 549 priv->baud_rate = tty_termios_baud_rate(old_termios); 550 tty_termios_copy_hw(&tty->termios, old_termios); 551 } else if (r == 0) { 552 priv->lcr = lcr; 553 } 554 } 555 556 spin_lock_irqsave(&priv->lock, flags); 557 if (C_BAUD(tty) == B0) 558 priv->mcr &= ~(CH341_BIT_DTR | CH341_BIT_RTS); 559 else if (old_termios && (old_termios->c_cflag & CBAUD) == B0) 560 priv->mcr |= (CH341_BIT_DTR | CH341_BIT_RTS); 561 spin_unlock_irqrestore(&priv->lock, flags); 562 563 ch341_set_handshake(port->serial->dev, priv->mcr); 564 } 565 566 /* 567 * A subset of all CH34x devices don't support a real break condition and 568 * reading CH341_REG_BREAK fails (see also ch341_detect_quirks). This function 569 * simulates a break condition by lowering the baud rate to the minimum 570 * supported by the hardware upon enabling the break condition and sending 571 * a NUL byte. 572 * 573 * Incoming data is corrupted while the break condition is being simulated. 574 * 575 * Normally the duration of the break condition can be controlled individually 576 * by userspace using TIOCSBRK and TIOCCBRK or by passing an argument to 577 * TCSBRKP. Due to how the simulation is implemented the duration can't be 578 * controlled. The duration is always about (1s / 46bd * 9bit) = 196ms. 579 */ 580 static void ch341_simulate_break(struct tty_struct *tty, int break_state) 581 { 582 struct usb_serial_port *port = tty->driver_data; 583 struct ch341_private *priv = usb_get_serial_port_data(port); 584 unsigned long now, delay; 585 int r; 586 587 if (break_state != 0) { 588 dev_dbg(&port->dev, "enter break state requested\n"); 589 590 r = ch341_set_baudrate_lcr(port->serial->dev, priv, 591 CH341_MIN_BPS, 592 CH341_LCR_ENABLE_RX | CH341_LCR_ENABLE_TX | CH341_LCR_CS8); 593 if (r < 0) { 594 dev_err(&port->dev, 595 "failed to change baud rate to %u: %d\n", 596 CH341_MIN_BPS, r); 597 goto restore; 598 } 599 600 r = tty_put_char(tty, '\0'); 601 if (r < 0) { 602 dev_err(&port->dev, 603 "failed to write NUL byte for simulated break condition: %d\n", 604 r); 605 goto restore; 606 } 607 608 /* 609 * Compute expected transmission duration including safety 610 * margin. The original baud rate is only restored after the 611 * computed point in time. 612 * 613 * 11 bits = 1 start, 8 data, 1 stop, 1 margin 614 */ 615 priv->break_end = jiffies + (11 * HZ / CH341_MIN_BPS); 616 617 return; 618 } 619 620 dev_dbg(&port->dev, "leave break state requested\n"); 621 622 now = jiffies; 623 624 if (time_before(now, priv->break_end)) { 625 /* Wait until NUL byte is written */ 626 delay = priv->break_end - now; 627 dev_dbg(&port->dev, 628 "wait %d ms while transmitting NUL byte at %u baud\n", 629 jiffies_to_msecs(delay), CH341_MIN_BPS); 630 schedule_timeout_interruptible(delay); 631 } 632 633 restore: 634 /* Restore original baud rate */ 635 r = ch341_set_baudrate_lcr(port->serial->dev, priv, priv->baud_rate, 636 priv->lcr); 637 if (r < 0) 638 dev_err(&port->dev, 639 "restoring original baud rate of %u failed: %d\n", 640 priv->baud_rate, r); 641 } 642 643 static void ch341_break_ctl(struct tty_struct *tty, int break_state) 644 { 645 const uint16_t ch341_break_reg = 646 ((uint16_t) CH341_REG_LCR << 8) | CH341_REG_BREAK; 647 struct usb_serial_port *port = tty->driver_data; 648 struct ch341_private *priv = usb_get_serial_port_data(port); 649 int r; 650 uint16_t reg_contents; 651 uint8_t *break_reg; 652 653 if (priv->quirks & CH341_QUIRK_SIMULATE_BREAK) { 654 ch341_simulate_break(tty, break_state); 655 return; 656 } 657 658 break_reg = kmalloc(2, GFP_KERNEL); 659 if (!break_reg) 660 return; 661 662 r = ch341_control_in(port->serial->dev, CH341_REQ_READ_REG, 663 ch341_break_reg, 0, break_reg, 2); 664 if (r < 0) { 665 dev_err(&port->dev, "%s - USB control read error (%d)\n", 666 __func__, r); 667 goto out; 668 } 669 dev_dbg(&port->dev, "%s - initial ch341 break register contents - reg1: %x, reg2: %x\n", 670 __func__, break_reg[0], break_reg[1]); 671 if (break_state != 0) { 672 dev_dbg(&port->dev, "%s - Enter break state requested\n", __func__); 673 break_reg[0] &= ~CH341_NBREAK_BITS; 674 break_reg[1] &= ~CH341_LCR_ENABLE_TX; 675 } else { 676 dev_dbg(&port->dev, "%s - Leave break state requested\n", __func__); 677 break_reg[0] |= CH341_NBREAK_BITS; 678 break_reg[1] |= CH341_LCR_ENABLE_TX; 679 } 680 dev_dbg(&port->dev, "%s - New ch341 break register contents - reg1: %x, reg2: %x\n", 681 __func__, break_reg[0], break_reg[1]); 682 reg_contents = get_unaligned_le16(break_reg); 683 r = ch341_control_out(port->serial->dev, CH341_REQ_WRITE_REG, 684 ch341_break_reg, reg_contents); 685 if (r < 0) 686 dev_err(&port->dev, "%s - USB control write error (%d)\n", 687 __func__, r); 688 out: 689 kfree(break_reg); 690 } 691 692 static int ch341_tiocmset(struct tty_struct *tty, 693 unsigned int set, unsigned int clear) 694 { 695 struct usb_serial_port *port = tty->driver_data; 696 struct ch341_private *priv = usb_get_serial_port_data(port); 697 unsigned long flags; 698 u8 control; 699 700 spin_lock_irqsave(&priv->lock, flags); 701 if (set & TIOCM_RTS) 702 priv->mcr |= CH341_BIT_RTS; 703 if (set & TIOCM_DTR) 704 priv->mcr |= CH341_BIT_DTR; 705 if (clear & TIOCM_RTS) 706 priv->mcr &= ~CH341_BIT_RTS; 707 if (clear & TIOCM_DTR) 708 priv->mcr &= ~CH341_BIT_DTR; 709 control = priv->mcr; 710 spin_unlock_irqrestore(&priv->lock, flags); 711 712 return ch341_set_handshake(port->serial->dev, control); 713 } 714 715 static void ch341_update_status(struct usb_serial_port *port, 716 unsigned char *data, size_t len) 717 { 718 struct ch341_private *priv = usb_get_serial_port_data(port); 719 struct tty_struct *tty; 720 unsigned long flags; 721 u8 status; 722 u8 delta; 723 724 if (len < 4) 725 return; 726 727 status = ~data[2] & CH341_BITS_MODEM_STAT; 728 729 spin_lock_irqsave(&priv->lock, flags); 730 delta = status ^ priv->msr; 731 priv->msr = status; 732 spin_unlock_irqrestore(&priv->lock, flags); 733 734 if (data[1] & CH341_MULT_STAT) 735 dev_dbg(&port->dev, "%s - multiple status change\n", __func__); 736 737 if (!delta) 738 return; 739 740 if (delta & CH341_BIT_CTS) 741 port->icount.cts++; 742 if (delta & CH341_BIT_DSR) 743 port->icount.dsr++; 744 if (delta & CH341_BIT_RI) 745 port->icount.rng++; 746 if (delta & CH341_BIT_DCD) { 747 port->icount.dcd++; 748 tty = tty_port_tty_get(&port->port); 749 if (tty) { 750 usb_serial_handle_dcd_change(port, tty, 751 status & CH341_BIT_DCD); 752 tty_kref_put(tty); 753 } 754 } 755 756 wake_up_interruptible(&port->port.delta_msr_wait); 757 } 758 759 static void ch341_read_int_callback(struct urb *urb) 760 { 761 struct usb_serial_port *port = urb->context; 762 unsigned char *data = urb->transfer_buffer; 763 unsigned int len = urb->actual_length; 764 int status; 765 766 switch (urb->status) { 767 case 0: 768 /* success */ 769 break; 770 case -ECONNRESET: 771 case -ENOENT: 772 case -ESHUTDOWN: 773 /* this urb is terminated, clean up */ 774 dev_dbg(&urb->dev->dev, "%s - urb shutting down: %d\n", 775 __func__, urb->status); 776 return; 777 default: 778 dev_dbg(&urb->dev->dev, "%s - nonzero urb status: %d\n", 779 __func__, urb->status); 780 goto exit; 781 } 782 783 usb_serial_debug_data(&port->dev, __func__, len, data); 784 ch341_update_status(port, data, len); 785 exit: 786 status = usb_submit_urb(urb, GFP_ATOMIC); 787 if (status) { 788 dev_err(&urb->dev->dev, "%s - usb_submit_urb failed: %d\n", 789 __func__, status); 790 } 791 } 792 793 static int ch341_tiocmget(struct tty_struct *tty) 794 { 795 struct usb_serial_port *port = tty->driver_data; 796 struct ch341_private *priv = usb_get_serial_port_data(port); 797 unsigned long flags; 798 u8 mcr; 799 u8 status; 800 unsigned int result; 801 802 spin_lock_irqsave(&priv->lock, flags); 803 mcr = priv->mcr; 804 status = priv->msr; 805 spin_unlock_irqrestore(&priv->lock, flags); 806 807 result = ((mcr & CH341_BIT_DTR) ? TIOCM_DTR : 0) 808 | ((mcr & CH341_BIT_RTS) ? TIOCM_RTS : 0) 809 | ((status & CH341_BIT_CTS) ? TIOCM_CTS : 0) 810 | ((status & CH341_BIT_DSR) ? TIOCM_DSR : 0) 811 | ((status & CH341_BIT_RI) ? TIOCM_RI : 0) 812 | ((status & CH341_BIT_DCD) ? TIOCM_CD : 0); 813 814 dev_dbg(&port->dev, "%s - result = %x\n", __func__, result); 815 816 return result; 817 } 818 819 static int ch341_reset_resume(struct usb_serial *serial) 820 { 821 struct usb_serial_port *port = serial->port[0]; 822 struct ch341_private *priv; 823 int ret; 824 825 priv = usb_get_serial_port_data(port); 826 if (!priv) 827 return 0; 828 829 /* reconfigure ch341 serial port after bus-reset */ 830 ch341_configure(serial->dev, priv); 831 832 if (tty_port_initialized(&port->port)) { 833 ret = usb_submit_urb(port->interrupt_in_urb, GFP_NOIO); 834 if (ret) { 835 dev_err(&port->dev, "failed to submit interrupt urb: %d\n", 836 ret); 837 return ret; 838 } 839 840 ret = ch341_get_status(port->serial->dev, priv); 841 if (ret < 0) { 842 dev_err(&port->dev, "failed to read modem status: %d\n", 843 ret); 844 } 845 } 846 847 return usb_serial_generic_resume(serial); 848 } 849 850 static struct usb_serial_driver ch341_device = { 851 .driver = { 852 .owner = THIS_MODULE, 853 .name = "ch341-uart", 854 }, 855 .id_table = id_table, 856 .num_ports = 1, 857 .open = ch341_open, 858 .dtr_rts = ch341_dtr_rts, 859 .carrier_raised = ch341_carrier_raised, 860 .close = ch341_close, 861 .set_termios = ch341_set_termios, 862 .break_ctl = ch341_break_ctl, 863 .tiocmget = ch341_tiocmget, 864 .tiocmset = ch341_tiocmset, 865 .tiocmiwait = usb_serial_generic_tiocmiwait, 866 .read_int_callback = ch341_read_int_callback, 867 .port_probe = ch341_port_probe, 868 .port_remove = ch341_port_remove, 869 .reset_resume = ch341_reset_resume, 870 }; 871 872 static struct usb_serial_driver * const serial_drivers[] = { 873 &ch341_device, NULL 874 }; 875 876 module_usb_serial_driver(serial_drivers, id_table); 877 878 MODULE_LICENSE("GPL v2"); 879