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