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, 0x5523) }, 85 { USB_DEVICE(0x1a86, 0x7522) }, 86 { USB_DEVICE(0x1a86, 0x7523) }, 87 { USB_DEVICE(0x2184, 0x0057) }, 88 { USB_DEVICE(0x4348, 0x5523) }, 89 { USB_DEVICE(0x9986, 0x7523) }, 90 { }, 91 }; 92 MODULE_DEVICE_TABLE(usb, id_table); 93 94 struct ch341_private { 95 spinlock_t lock; /* access lock */ 96 unsigned baud_rate; /* set baud rate */ 97 u8 mcr; 98 u8 msr; 99 u8 lcr; 100 101 unsigned long quirks; 102 u8 version; 103 104 unsigned long break_end; 105 }; 106 107 static void ch341_set_termios(struct tty_struct *tty, 108 struct usb_serial_port *port, 109 const struct ktermios *old_termios); 110 111 static int ch341_control_out(struct usb_device *dev, u8 request, 112 u16 value, u16 index) 113 { 114 int r; 115 116 dev_dbg(&dev->dev, "%s - (%02x,%04x,%04x)\n", __func__, 117 request, value, index); 118 119 r = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), request, 120 USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT, 121 value, index, NULL, 0, DEFAULT_TIMEOUT); 122 if (r < 0) 123 dev_err(&dev->dev, "failed to send control message: %d\n", r); 124 125 return r; 126 } 127 128 static int ch341_control_in(struct usb_device *dev, 129 u8 request, u16 value, u16 index, 130 char *buf, unsigned bufsize) 131 { 132 int r; 133 134 dev_dbg(&dev->dev, "%s - (%02x,%04x,%04x,%u)\n", __func__, 135 request, value, index, bufsize); 136 137 r = usb_control_msg_recv(dev, 0, request, 138 USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN, 139 value, index, buf, bufsize, DEFAULT_TIMEOUT, 140 GFP_KERNEL); 141 if (r) { 142 dev_err(&dev->dev, "failed to receive control message: %d\n", 143 r); 144 return r; 145 } 146 147 return 0; 148 } 149 150 #define CH341_CLKRATE 48000000 151 #define CH341_CLK_DIV(ps, fact) (1 << (12 - 3 * (ps) - (fact))) 152 #define CH341_MIN_RATE(ps) (CH341_CLKRATE / (CH341_CLK_DIV((ps), 1) * 512)) 153 154 static const speed_t ch341_min_rates[] = { 155 CH341_MIN_RATE(0), 156 CH341_MIN_RATE(1), 157 CH341_MIN_RATE(2), 158 CH341_MIN_RATE(3), 159 }; 160 161 /* Supported range is 46 to 3000000 bps. */ 162 #define CH341_MIN_BPS DIV_ROUND_UP(CH341_CLKRATE, CH341_CLK_DIV(0, 0) * 256) 163 #define CH341_MAX_BPS (CH341_CLKRATE / (CH341_CLK_DIV(3, 0) * 2)) 164 165 /* 166 * The device line speed is given by the following equation: 167 * 168 * baudrate = 48000000 / (2^(12 - 3 * ps - fact) * div), where 169 * 170 * 0 <= ps <= 3, 171 * 0 <= fact <= 1, 172 * 2 <= div <= 256 if fact = 0, or 173 * 9 <= div <= 256 if fact = 1 174 */ 175 static int ch341_get_divisor(struct ch341_private *priv, speed_t speed) 176 { 177 unsigned int fact, div, clk_div; 178 bool force_fact0 = false; 179 int ps; 180 181 /* 182 * Clamp to supported range, this makes the (ps < 0) and (div < 2) 183 * sanity checks below redundant. 184 */ 185 speed = clamp_val(speed, CH341_MIN_BPS, CH341_MAX_BPS); 186 187 /* 188 * Start with highest possible base clock (fact = 1) that will give a 189 * divisor strictly less than 512. 190 */ 191 fact = 1; 192 for (ps = 3; ps >= 0; ps--) { 193 if (speed > ch341_min_rates[ps]) 194 break; 195 } 196 197 if (ps < 0) 198 return -EINVAL; 199 200 /* Determine corresponding divisor, rounding down. */ 201 clk_div = CH341_CLK_DIV(ps, fact); 202 div = CH341_CLKRATE / (clk_div * speed); 203 204 /* Some devices require a lower base clock if ps < 3. */ 205 if (ps < 3 && (priv->quirks & CH341_QUIRK_LIMITED_PRESCALER)) 206 force_fact0 = true; 207 208 /* Halve base clock (fact = 0) if required. */ 209 if (div < 9 || div > 255 || force_fact0) { 210 div /= 2; 211 clk_div *= 2; 212 fact = 0; 213 } 214 215 if (div < 2) 216 return -EINVAL; 217 218 /* 219 * Pick next divisor if resulting rate is closer to the requested one, 220 * scale up to avoid rounding errors on low rates. 221 */ 222 if (16 * CH341_CLKRATE / (clk_div * div) - 16 * speed >= 223 16 * speed - 16 * CH341_CLKRATE / (clk_div * (div + 1))) 224 div++; 225 226 /* 227 * Prefer lower base clock (fact = 0) if even divisor. 228 * 229 * Note that this makes the receiver more tolerant to errors. 230 */ 231 if (fact == 1 && div % 2 == 0) { 232 div /= 2; 233 fact = 0; 234 } 235 236 return (0x100 - div) << 8 | fact << 2 | ps; 237 } 238 239 static int ch341_set_baudrate_lcr(struct usb_device *dev, 240 struct ch341_private *priv, 241 speed_t baud_rate, u8 lcr) 242 { 243 int val; 244 int r; 245 246 if (!baud_rate) 247 return -EINVAL; 248 249 val = ch341_get_divisor(priv, baud_rate); 250 if (val < 0) 251 return -EINVAL; 252 253 /* 254 * CH341A buffers data until a full endpoint-size packet (32 bytes) 255 * has been received unless bit 7 is set. 256 * 257 * At least one device with version 0x27 appears to have this bit 258 * inverted. 259 */ 260 if (priv->version > 0x27) 261 val |= BIT(7); 262 263 r = ch341_control_out(dev, CH341_REQ_WRITE_REG, 264 CH341_REG_DIVISOR << 8 | CH341_REG_PRESCALER, 265 val); 266 if (r) 267 return r; 268 269 /* 270 * Chip versions before version 0x30 as read using 271 * CH341_REQ_READ_VERSION used separate registers for line control 272 * (stop bits, parity and word length). Version 0x30 and above use 273 * CH341_REG_LCR only and CH341_REG_LCR2 is always set to zero. 274 */ 275 if (priv->version < 0x30) 276 return 0; 277 278 r = ch341_control_out(dev, CH341_REQ_WRITE_REG, 279 CH341_REG_LCR2 << 8 | CH341_REG_LCR, lcr); 280 if (r) 281 return r; 282 283 return r; 284 } 285 286 static int ch341_set_handshake(struct usb_device *dev, u8 control) 287 { 288 return ch341_control_out(dev, CH341_REQ_MODEM_CTRL, ~control, 0); 289 } 290 291 static int ch341_get_status(struct usb_device *dev, struct ch341_private *priv) 292 { 293 const unsigned int size = 2; 294 u8 buffer[2]; 295 int r; 296 unsigned long flags; 297 298 r = ch341_control_in(dev, CH341_REQ_READ_REG, 0x0706, 0, buffer, size); 299 if (r) 300 return r; 301 302 spin_lock_irqsave(&priv->lock, flags); 303 priv->msr = (~(*buffer)) & CH341_BITS_MODEM_STAT; 304 spin_unlock_irqrestore(&priv->lock, flags); 305 306 return 0; 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 u8 buffer[2]; 315 int r; 316 317 /* expect two bytes 0x27 0x00 */ 318 r = ch341_control_in(dev, CH341_REQ_READ_VERSION, 0, 0, buffer, size); 319 if (r) 320 return r; 321 322 priv->version = buffer[0]; 323 dev_dbg(&dev->dev, "Chip version: 0x%02x\n", priv->version); 324 325 r = ch341_control_out(dev, CH341_REQ_SERIAL_INIT, 0, 0); 326 if (r < 0) 327 return r; 328 329 r = ch341_set_baudrate_lcr(dev, priv, priv->baud_rate, priv->lcr); 330 if (r < 0) 331 return r; 332 333 r = ch341_set_handshake(dev, priv->mcr); 334 if (r < 0) 335 return r; 336 337 return 0; 338 } 339 340 static int ch341_detect_quirks(struct usb_serial_port *port) 341 { 342 struct ch341_private *priv = usb_get_serial_port_data(port); 343 struct usb_device *udev = port->serial->dev; 344 const unsigned int size = 2; 345 unsigned long quirks = 0; 346 u8 buffer[2]; 347 int r; 348 349 /* 350 * A subset of CH34x devices does not support all features. The 351 * prescaler is limited and there is no support for sending a RS232 352 * break condition. A read failure when trying to set up the latter is 353 * used to detect these devices. 354 */ 355 r = usb_control_msg_recv(udev, 0, CH341_REQ_READ_REG, 356 USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN, 357 CH341_REG_BREAK, 0, &buffer, size, 358 DEFAULT_TIMEOUT, GFP_KERNEL); 359 if (r == -EPIPE) { 360 dev_info(&port->dev, "break control not supported, using simulated break\n"); 361 quirks = CH341_QUIRK_LIMITED_PRESCALER | CH341_QUIRK_SIMULATE_BREAK; 362 r = 0; 363 } else if (r) { 364 dev_err(&port->dev, "failed to read break control: %d\n", r); 365 } 366 367 if (quirks) { 368 dev_dbg(&port->dev, "enabling quirk flags: 0x%02lx\n", quirks); 369 priv->quirks |= quirks; 370 } 371 372 return r; 373 } 374 375 static int ch341_port_probe(struct usb_serial_port *port) 376 { 377 struct ch341_private *priv; 378 int r; 379 380 priv = kzalloc(sizeof(struct ch341_private), GFP_KERNEL); 381 if (!priv) 382 return -ENOMEM; 383 384 spin_lock_init(&priv->lock); 385 priv->baud_rate = DEFAULT_BAUD_RATE; 386 /* 387 * Some CH340 devices appear unable to change the initial LCR 388 * settings, so set a sane 8N1 default. 389 */ 390 priv->lcr = CH341_LCR_ENABLE_RX | CH341_LCR_ENABLE_TX | CH341_LCR_CS8; 391 392 r = ch341_configure(port->serial->dev, priv); 393 if (r < 0) 394 goto error; 395 396 usb_set_serial_port_data(port, priv); 397 398 r = ch341_detect_quirks(port); 399 if (r < 0) 400 goto error; 401 402 return 0; 403 404 error: kfree(priv); 405 return r; 406 } 407 408 static void ch341_port_remove(struct usb_serial_port *port) 409 { 410 struct ch341_private *priv; 411 412 priv = usb_get_serial_port_data(port); 413 kfree(priv); 414 } 415 416 static int ch341_carrier_raised(struct usb_serial_port *port) 417 { 418 struct ch341_private *priv = usb_get_serial_port_data(port); 419 if (priv->msr & CH341_BIT_DCD) 420 return 1; 421 return 0; 422 } 423 424 static void ch341_dtr_rts(struct usb_serial_port *port, int on) 425 { 426 struct ch341_private *priv = usb_get_serial_port_data(port); 427 unsigned long flags; 428 429 /* drop DTR and RTS */ 430 spin_lock_irqsave(&priv->lock, flags); 431 if (on) 432 priv->mcr |= CH341_BIT_RTS | CH341_BIT_DTR; 433 else 434 priv->mcr &= ~(CH341_BIT_RTS | CH341_BIT_DTR); 435 spin_unlock_irqrestore(&priv->lock, flags); 436 ch341_set_handshake(port->serial->dev, priv->mcr); 437 } 438 439 static void ch341_close(struct usb_serial_port *port) 440 { 441 usb_serial_generic_close(port); 442 usb_kill_urb(port->interrupt_in_urb); 443 } 444 445 446 /* open this device, set default parameters */ 447 static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port) 448 { 449 struct ch341_private *priv = usb_get_serial_port_data(port); 450 int r; 451 452 if (tty) 453 ch341_set_termios(tty, port, NULL); 454 455 dev_dbg(&port->dev, "%s - submitting interrupt urb\n", __func__); 456 r = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL); 457 if (r) { 458 dev_err(&port->dev, "%s - failed to submit interrupt urb: %d\n", 459 __func__, r); 460 return r; 461 } 462 463 r = ch341_get_status(port->serial->dev, priv); 464 if (r < 0) { 465 dev_err(&port->dev, "failed to read modem status: %d\n", r); 466 goto err_kill_interrupt_urb; 467 } 468 469 r = usb_serial_generic_open(tty, port); 470 if (r) 471 goto err_kill_interrupt_urb; 472 473 return 0; 474 475 err_kill_interrupt_urb: 476 usb_kill_urb(port->interrupt_in_urb); 477 478 return r; 479 } 480 481 /* Old_termios contains the original termios settings and 482 * tty->termios contains the new setting to be used. 483 */ 484 static void ch341_set_termios(struct tty_struct *tty, 485 struct usb_serial_port *port, 486 const struct ktermios *old_termios) 487 { 488 struct ch341_private *priv = usb_get_serial_port_data(port); 489 unsigned baud_rate; 490 unsigned long flags; 491 u8 lcr; 492 int r; 493 494 /* redundant changes may cause the chip to lose bytes */ 495 if (old_termios && !tty_termios_hw_change(&tty->termios, old_termios)) 496 return; 497 498 baud_rate = tty_get_baud_rate(tty); 499 500 lcr = CH341_LCR_ENABLE_RX | CH341_LCR_ENABLE_TX; 501 502 switch (C_CSIZE(tty)) { 503 case CS5: 504 lcr |= CH341_LCR_CS5; 505 break; 506 case CS6: 507 lcr |= CH341_LCR_CS6; 508 break; 509 case CS7: 510 lcr |= CH341_LCR_CS7; 511 break; 512 case CS8: 513 lcr |= CH341_LCR_CS8; 514 break; 515 } 516 517 if (C_PARENB(tty)) { 518 lcr |= CH341_LCR_ENABLE_PAR; 519 if (C_PARODD(tty) == 0) 520 lcr |= CH341_LCR_PAR_EVEN; 521 if (C_CMSPAR(tty)) 522 lcr |= CH341_LCR_MARK_SPACE; 523 } 524 525 if (C_CSTOPB(tty)) 526 lcr |= CH341_LCR_STOP_BITS_2; 527 528 if (baud_rate) { 529 priv->baud_rate = baud_rate; 530 531 r = ch341_set_baudrate_lcr(port->serial->dev, priv, 532 priv->baud_rate, lcr); 533 if (r < 0 && old_termios) { 534 priv->baud_rate = tty_termios_baud_rate(old_termios); 535 tty_termios_copy_hw(&tty->termios, old_termios); 536 } else if (r == 0) { 537 priv->lcr = lcr; 538 } 539 } 540 541 spin_lock_irqsave(&priv->lock, flags); 542 if (C_BAUD(tty) == B0) 543 priv->mcr &= ~(CH341_BIT_DTR | CH341_BIT_RTS); 544 else if (old_termios && (old_termios->c_cflag & CBAUD) == B0) 545 priv->mcr |= (CH341_BIT_DTR | CH341_BIT_RTS); 546 spin_unlock_irqrestore(&priv->lock, flags); 547 548 ch341_set_handshake(port->serial->dev, priv->mcr); 549 } 550 551 /* 552 * A subset of all CH34x devices don't support a real break condition and 553 * reading CH341_REG_BREAK fails (see also ch341_detect_quirks). This function 554 * simulates a break condition by lowering the baud rate to the minimum 555 * supported by the hardware upon enabling the break condition and sending 556 * a NUL byte. 557 * 558 * Incoming data is corrupted while the break condition is being simulated. 559 * 560 * Normally the duration of the break condition can be controlled individually 561 * by userspace using TIOCSBRK and TIOCCBRK or by passing an argument to 562 * TCSBRKP. Due to how the simulation is implemented the duration can't be 563 * controlled. The duration is always about (1s / 46bd * 9bit) = 196ms. 564 */ 565 static void ch341_simulate_break(struct tty_struct *tty, int break_state) 566 { 567 struct usb_serial_port *port = tty->driver_data; 568 struct ch341_private *priv = usb_get_serial_port_data(port); 569 unsigned long now, delay; 570 int r; 571 572 if (break_state != 0) { 573 dev_dbg(&port->dev, "enter break state requested\n"); 574 575 r = ch341_set_baudrate_lcr(port->serial->dev, priv, 576 CH341_MIN_BPS, 577 CH341_LCR_ENABLE_RX | CH341_LCR_ENABLE_TX | CH341_LCR_CS8); 578 if (r < 0) { 579 dev_err(&port->dev, 580 "failed to change baud rate to %u: %d\n", 581 CH341_MIN_BPS, r); 582 goto restore; 583 } 584 585 r = tty_put_char(tty, '\0'); 586 if (r < 0) { 587 dev_err(&port->dev, 588 "failed to write NUL byte for simulated break condition: %d\n", 589 r); 590 goto restore; 591 } 592 593 /* 594 * Compute expected transmission duration including safety 595 * margin. The original baud rate is only restored after the 596 * computed point in time. 597 * 598 * 11 bits = 1 start, 8 data, 1 stop, 1 margin 599 */ 600 priv->break_end = jiffies + (11 * HZ / CH341_MIN_BPS); 601 602 return; 603 } 604 605 dev_dbg(&port->dev, "leave break state requested\n"); 606 607 now = jiffies; 608 609 if (time_before(now, priv->break_end)) { 610 /* Wait until NUL byte is written */ 611 delay = priv->break_end - now; 612 dev_dbg(&port->dev, 613 "wait %d ms while transmitting NUL byte at %u baud\n", 614 jiffies_to_msecs(delay), CH341_MIN_BPS); 615 schedule_timeout_interruptible(delay); 616 } 617 618 restore: 619 /* Restore original baud rate */ 620 r = ch341_set_baudrate_lcr(port->serial->dev, priv, priv->baud_rate, 621 priv->lcr); 622 if (r < 0) 623 dev_err(&port->dev, 624 "restoring original baud rate of %u failed: %d\n", 625 priv->baud_rate, r); 626 } 627 628 static void ch341_break_ctl(struct tty_struct *tty, int break_state) 629 { 630 const uint16_t ch341_break_reg = 631 ((uint16_t) CH341_REG_LCR << 8) | CH341_REG_BREAK; 632 struct usb_serial_port *port = tty->driver_data; 633 struct ch341_private *priv = usb_get_serial_port_data(port); 634 int r; 635 uint16_t reg_contents; 636 uint8_t break_reg[2]; 637 638 if (priv->quirks & CH341_QUIRK_SIMULATE_BREAK) { 639 ch341_simulate_break(tty, break_state); 640 return; 641 } 642 643 r = ch341_control_in(port->serial->dev, CH341_REQ_READ_REG, 644 ch341_break_reg, 0, break_reg, 2); 645 if (r) { 646 dev_err(&port->dev, "%s - USB control read error (%d)\n", 647 __func__, r); 648 return; 649 } 650 dev_dbg(&port->dev, "%s - initial ch341 break register contents - reg1: %x, reg2: %x\n", 651 __func__, break_reg[0], break_reg[1]); 652 if (break_state != 0) { 653 dev_dbg(&port->dev, "%s - Enter break state requested\n", __func__); 654 break_reg[0] &= ~CH341_NBREAK_BITS; 655 break_reg[1] &= ~CH341_LCR_ENABLE_TX; 656 } else { 657 dev_dbg(&port->dev, "%s - Leave break state requested\n", __func__); 658 break_reg[0] |= CH341_NBREAK_BITS; 659 break_reg[1] |= CH341_LCR_ENABLE_TX; 660 } 661 dev_dbg(&port->dev, "%s - New ch341 break register contents - reg1: %x, reg2: %x\n", 662 __func__, break_reg[0], break_reg[1]); 663 reg_contents = get_unaligned_le16(break_reg); 664 r = ch341_control_out(port->serial->dev, CH341_REQ_WRITE_REG, 665 ch341_break_reg, reg_contents); 666 if (r < 0) 667 dev_err(&port->dev, "%s - USB control write error (%d)\n", 668 __func__, r); 669 } 670 671 static int ch341_tiocmset(struct tty_struct *tty, 672 unsigned int set, unsigned int clear) 673 { 674 struct usb_serial_port *port = tty->driver_data; 675 struct ch341_private *priv = usb_get_serial_port_data(port); 676 unsigned long flags; 677 u8 control; 678 679 spin_lock_irqsave(&priv->lock, flags); 680 if (set & TIOCM_RTS) 681 priv->mcr |= CH341_BIT_RTS; 682 if (set & TIOCM_DTR) 683 priv->mcr |= CH341_BIT_DTR; 684 if (clear & TIOCM_RTS) 685 priv->mcr &= ~CH341_BIT_RTS; 686 if (clear & TIOCM_DTR) 687 priv->mcr &= ~CH341_BIT_DTR; 688 control = priv->mcr; 689 spin_unlock_irqrestore(&priv->lock, flags); 690 691 return ch341_set_handshake(port->serial->dev, control); 692 } 693 694 static void ch341_update_status(struct usb_serial_port *port, 695 unsigned char *data, size_t len) 696 { 697 struct ch341_private *priv = usb_get_serial_port_data(port); 698 struct tty_struct *tty; 699 unsigned long flags; 700 u8 status; 701 u8 delta; 702 703 if (len < 4) 704 return; 705 706 status = ~data[2] & CH341_BITS_MODEM_STAT; 707 708 spin_lock_irqsave(&priv->lock, flags); 709 delta = status ^ priv->msr; 710 priv->msr = status; 711 spin_unlock_irqrestore(&priv->lock, flags); 712 713 if (data[1] & CH341_MULT_STAT) 714 dev_dbg(&port->dev, "%s - multiple status change\n", __func__); 715 716 if (!delta) 717 return; 718 719 if (delta & CH341_BIT_CTS) 720 port->icount.cts++; 721 if (delta & CH341_BIT_DSR) 722 port->icount.dsr++; 723 if (delta & CH341_BIT_RI) 724 port->icount.rng++; 725 if (delta & CH341_BIT_DCD) { 726 port->icount.dcd++; 727 tty = tty_port_tty_get(&port->port); 728 if (tty) { 729 usb_serial_handle_dcd_change(port, tty, 730 status & CH341_BIT_DCD); 731 tty_kref_put(tty); 732 } 733 } 734 735 wake_up_interruptible(&port->port.delta_msr_wait); 736 } 737 738 static void ch341_read_int_callback(struct urb *urb) 739 { 740 struct usb_serial_port *port = urb->context; 741 unsigned char *data = urb->transfer_buffer; 742 unsigned int len = urb->actual_length; 743 int status; 744 745 switch (urb->status) { 746 case 0: 747 /* success */ 748 break; 749 case -ECONNRESET: 750 case -ENOENT: 751 case -ESHUTDOWN: 752 /* this urb is terminated, clean up */ 753 dev_dbg(&urb->dev->dev, "%s - urb shutting down: %d\n", 754 __func__, urb->status); 755 return; 756 default: 757 dev_dbg(&urb->dev->dev, "%s - nonzero urb status: %d\n", 758 __func__, urb->status); 759 goto exit; 760 } 761 762 usb_serial_debug_data(&port->dev, __func__, len, data); 763 ch341_update_status(port, data, len); 764 exit: 765 status = usb_submit_urb(urb, GFP_ATOMIC); 766 if (status) { 767 dev_err(&urb->dev->dev, "%s - usb_submit_urb failed: %d\n", 768 __func__, status); 769 } 770 } 771 772 static int ch341_tiocmget(struct tty_struct *tty) 773 { 774 struct usb_serial_port *port = tty->driver_data; 775 struct ch341_private *priv = usb_get_serial_port_data(port); 776 unsigned long flags; 777 u8 mcr; 778 u8 status; 779 unsigned int result; 780 781 spin_lock_irqsave(&priv->lock, flags); 782 mcr = priv->mcr; 783 status = priv->msr; 784 spin_unlock_irqrestore(&priv->lock, flags); 785 786 result = ((mcr & CH341_BIT_DTR) ? TIOCM_DTR : 0) 787 | ((mcr & CH341_BIT_RTS) ? TIOCM_RTS : 0) 788 | ((status & CH341_BIT_CTS) ? TIOCM_CTS : 0) 789 | ((status & CH341_BIT_DSR) ? TIOCM_DSR : 0) 790 | ((status & CH341_BIT_RI) ? TIOCM_RI : 0) 791 | ((status & CH341_BIT_DCD) ? TIOCM_CD : 0); 792 793 dev_dbg(&port->dev, "%s - result = %x\n", __func__, result); 794 795 return result; 796 } 797 798 static int ch341_reset_resume(struct usb_serial *serial) 799 { 800 struct usb_serial_port *port = serial->port[0]; 801 struct ch341_private *priv; 802 int ret; 803 804 priv = usb_get_serial_port_data(port); 805 if (!priv) 806 return 0; 807 808 /* reconfigure ch341 serial port after bus-reset */ 809 ch341_configure(serial->dev, priv); 810 811 if (tty_port_initialized(&port->port)) { 812 ret = usb_submit_urb(port->interrupt_in_urb, GFP_NOIO); 813 if (ret) { 814 dev_err(&port->dev, "failed to submit interrupt urb: %d\n", 815 ret); 816 return ret; 817 } 818 819 ret = ch341_get_status(port->serial->dev, priv); 820 if (ret < 0) { 821 dev_err(&port->dev, "failed to read modem status: %d\n", 822 ret); 823 } 824 } 825 826 return usb_serial_generic_resume(serial); 827 } 828 829 static struct usb_serial_driver ch341_device = { 830 .driver = { 831 .owner = THIS_MODULE, 832 .name = "ch341-uart", 833 }, 834 .id_table = id_table, 835 .num_ports = 1, 836 .open = ch341_open, 837 .dtr_rts = ch341_dtr_rts, 838 .carrier_raised = ch341_carrier_raised, 839 .close = ch341_close, 840 .set_termios = ch341_set_termios, 841 .break_ctl = ch341_break_ctl, 842 .tiocmget = ch341_tiocmget, 843 .tiocmset = ch341_tiocmset, 844 .tiocmiwait = usb_serial_generic_tiocmiwait, 845 .read_int_callback = ch341_read_int_callback, 846 .port_probe = ch341_port_probe, 847 .port_remove = ch341_port_remove, 848 .reset_resume = ch341_reset_resume, 849 }; 850 851 static struct usb_serial_driver * const serial_drivers[] = { 852 &ch341_device, NULL 853 }; 854 855 module_usb_serial_driver(serial_drivers, id_table); 856 857 MODULE_LICENSE("GPL v2"); 858