1 /* 2 * Copyright 2007, Frank A Kingswood <frank@kingswood-consulting.co.uk> 3 * Copyright 2007, Werner Cornelius <werner@cornelius-consult.de> 4 * Copyright 2009, Boris Hajduk <boris@hajduk.org> 5 * 6 * ch341.c implements a serial port driver for the Winchiphead CH341. 7 * 8 * The CH341 device can be used to implement an RS232 asynchronous 9 * serial port, an IEEE-1284 parallel printer port or a memory-like 10 * interface. In all cases the CH341 supports an I2C interface as well. 11 * This driver only supports the asynchronous serial interface. 12 * 13 * This program is free software; you can redistribute it and/or 14 * modify it under the terms of the GNU General Public License version 15 * 2 as published by the Free Software Foundation. 16 */ 17 18 #include <linux/kernel.h> 19 #include <linux/tty.h> 20 #include <linux/module.h> 21 #include <linux/slab.h> 22 #include <linux/usb.h> 23 #include <linux/usb/serial.h> 24 #include <linux/serial.h> 25 #include <asm/unaligned.h> 26 27 #define DEFAULT_BAUD_RATE 9600 28 #define DEFAULT_TIMEOUT 1000 29 30 /* flags for IO-Bits */ 31 #define CH341_BIT_RTS (1 << 6) 32 #define CH341_BIT_DTR (1 << 5) 33 34 /******************************/ 35 /* interrupt pipe definitions */ 36 /******************************/ 37 /* always 4 interrupt bytes */ 38 /* first irq byte normally 0x08 */ 39 /* second irq byte base 0x7d + below */ 40 /* third irq byte base 0x94 + below */ 41 /* fourth irq byte normally 0xee */ 42 43 /* second interrupt byte */ 44 #define CH341_MULT_STAT 0x04 /* multiple status since last interrupt event */ 45 46 /* status returned in third interrupt answer byte, inverted in data 47 from irq */ 48 #define CH341_BIT_CTS 0x01 49 #define CH341_BIT_DSR 0x02 50 #define CH341_BIT_RI 0x04 51 #define CH341_BIT_DCD 0x08 52 #define CH341_BITS_MODEM_STAT 0x0f /* all bits */ 53 54 /*******************************/ 55 /* baudrate calculation factor */ 56 /*******************************/ 57 #define CH341_BAUDBASE_FACTOR 1532620800 58 #define CH341_BAUDBASE_DIVMAX 3 59 60 /* Break support - the information used to implement this was gleaned from 61 * the Net/FreeBSD uchcom.c driver by Takanori Watanabe. Domo arigato. 62 */ 63 64 #define CH341_REQ_WRITE_REG 0x9A 65 #define CH341_REQ_READ_REG 0x95 66 #define CH341_REG_BREAK1 0x05 67 #define CH341_REG_BREAK2 0x18 68 #define CH341_NBREAK_BITS_REG1 0x01 69 #define CH341_NBREAK_BITS_REG2 0x40 70 71 72 static const struct usb_device_id id_table[] = { 73 { USB_DEVICE(0x4348, 0x5523) }, 74 { USB_DEVICE(0x1a86, 0x7523) }, 75 { USB_DEVICE(0x1a86, 0x5523) }, 76 { }, 77 }; 78 MODULE_DEVICE_TABLE(usb, id_table); 79 80 struct ch341_private { 81 spinlock_t lock; /* access lock */ 82 unsigned baud_rate; /* set baud rate */ 83 u8 line_control; /* set line control value RTS/DTR */ 84 u8 line_status; /* active status of modem control inputs */ 85 }; 86 87 static int ch341_control_out(struct usb_device *dev, u8 request, 88 u16 value, u16 index) 89 { 90 int r; 91 92 dev_dbg(&dev->dev, "ch341_control_out(%02x,%02x,%04x,%04x)\n", 93 USB_DIR_OUT|0x40, (int)request, (int)value, (int)index); 94 95 r = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), request, 96 USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT, 97 value, index, NULL, 0, DEFAULT_TIMEOUT); 98 99 return r; 100 } 101 102 static int ch341_control_in(struct usb_device *dev, 103 u8 request, u16 value, u16 index, 104 char *buf, unsigned bufsize) 105 { 106 int r; 107 108 dev_dbg(&dev->dev, "ch341_control_in(%02x,%02x,%04x,%04x,%p,%u)\n", 109 USB_DIR_IN|0x40, (int)request, (int)value, (int)index, buf, 110 (int)bufsize); 111 112 r = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), request, 113 USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN, 114 value, index, buf, bufsize, DEFAULT_TIMEOUT); 115 return r; 116 } 117 118 static int ch341_set_baudrate(struct usb_device *dev, 119 struct ch341_private *priv) 120 { 121 short a, b; 122 int r; 123 unsigned long factor; 124 short divisor; 125 126 if (!priv->baud_rate) 127 return -EINVAL; 128 factor = (CH341_BAUDBASE_FACTOR / priv->baud_rate); 129 divisor = CH341_BAUDBASE_DIVMAX; 130 131 while ((factor > 0xfff0) && divisor) { 132 factor >>= 3; 133 divisor--; 134 } 135 136 if (factor > 0xfff0) 137 return -EINVAL; 138 139 factor = 0x10000 - factor; 140 a = (factor & 0xff00) | divisor; 141 b = factor & 0xff; 142 143 r = ch341_control_out(dev, 0x9a, 0x1312, a); 144 if (!r) 145 r = ch341_control_out(dev, 0x9a, 0x0f2c, b); 146 147 return r; 148 } 149 150 static int ch341_set_handshake(struct usb_device *dev, u8 control) 151 { 152 return ch341_control_out(dev, 0xa4, ~control, 0); 153 } 154 155 static int ch341_get_status(struct usb_device *dev, struct ch341_private *priv) 156 { 157 char *buffer; 158 int r; 159 const unsigned size = 8; 160 unsigned long flags; 161 162 buffer = kmalloc(size, GFP_KERNEL); 163 if (!buffer) 164 return -ENOMEM; 165 166 r = ch341_control_in(dev, 0x95, 0x0706, 0, buffer, size); 167 if (r < 0) 168 goto out; 169 170 /* setup the private status if available */ 171 if (r == 2) { 172 r = 0; 173 spin_lock_irqsave(&priv->lock, flags); 174 priv->line_status = (~(*buffer)) & CH341_BITS_MODEM_STAT; 175 spin_unlock_irqrestore(&priv->lock, flags); 176 } else 177 r = -EPROTO; 178 179 out: kfree(buffer); 180 return r; 181 } 182 183 /* -------------------------------------------------------------------------- */ 184 185 static int ch341_configure(struct usb_device *dev, struct ch341_private *priv) 186 { 187 char *buffer; 188 int r; 189 const unsigned size = 8; 190 191 buffer = kmalloc(size, GFP_KERNEL); 192 if (!buffer) 193 return -ENOMEM; 194 195 /* expect two bytes 0x27 0x00 */ 196 r = ch341_control_in(dev, 0x5f, 0, 0, buffer, size); 197 if (r < 0) 198 goto out; 199 200 r = ch341_control_out(dev, 0xa1, 0, 0); 201 if (r < 0) 202 goto out; 203 204 r = ch341_set_baudrate(dev, priv); 205 if (r < 0) 206 goto out; 207 208 /* expect two bytes 0x56 0x00 */ 209 r = ch341_control_in(dev, 0x95, 0x2518, 0, buffer, size); 210 if (r < 0) 211 goto out; 212 213 r = ch341_control_out(dev, 0x9a, 0x2518, 0x0050); 214 if (r < 0) 215 goto out; 216 217 /* expect 0xff 0xee */ 218 r = ch341_get_status(dev, priv); 219 if (r < 0) 220 goto out; 221 222 r = ch341_control_out(dev, 0xa1, 0x501f, 0xd90a); 223 if (r < 0) 224 goto out; 225 226 r = ch341_set_baudrate(dev, priv); 227 if (r < 0) 228 goto out; 229 230 r = ch341_set_handshake(dev, priv->line_control); 231 if (r < 0) 232 goto out; 233 234 /* expect 0x9f 0xee */ 235 r = ch341_get_status(dev, priv); 236 237 out: kfree(buffer); 238 return r; 239 } 240 241 static int ch341_port_probe(struct usb_serial_port *port) 242 { 243 struct ch341_private *priv; 244 int r; 245 246 priv = kzalloc(sizeof(struct ch341_private), GFP_KERNEL); 247 if (!priv) 248 return -ENOMEM; 249 250 spin_lock_init(&priv->lock); 251 priv->baud_rate = DEFAULT_BAUD_RATE; 252 priv->line_control = CH341_BIT_RTS | CH341_BIT_DTR; 253 254 r = ch341_configure(port->serial->dev, priv); 255 if (r < 0) 256 goto error; 257 258 usb_set_serial_port_data(port, priv); 259 return 0; 260 261 error: kfree(priv); 262 return r; 263 } 264 265 static int ch341_port_remove(struct usb_serial_port *port) 266 { 267 struct ch341_private *priv; 268 269 priv = usb_get_serial_port_data(port); 270 kfree(priv); 271 272 return 0; 273 } 274 275 static int ch341_carrier_raised(struct usb_serial_port *port) 276 { 277 struct ch341_private *priv = usb_get_serial_port_data(port); 278 if (priv->line_status & CH341_BIT_DCD) 279 return 1; 280 return 0; 281 } 282 283 static void ch341_dtr_rts(struct usb_serial_port *port, int on) 284 { 285 struct ch341_private *priv = usb_get_serial_port_data(port); 286 unsigned long flags; 287 288 /* drop DTR and RTS */ 289 spin_lock_irqsave(&priv->lock, flags); 290 if (on) 291 priv->line_control |= CH341_BIT_RTS | CH341_BIT_DTR; 292 else 293 priv->line_control &= ~(CH341_BIT_RTS | CH341_BIT_DTR); 294 spin_unlock_irqrestore(&priv->lock, flags); 295 ch341_set_handshake(port->serial->dev, priv->line_control); 296 } 297 298 static void ch341_close(struct usb_serial_port *port) 299 { 300 usb_serial_generic_close(port); 301 usb_kill_urb(port->interrupt_in_urb); 302 } 303 304 305 /* open this device, set default parameters */ 306 static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port) 307 { 308 struct usb_serial *serial = port->serial; 309 struct ch341_private *priv = usb_get_serial_port_data(port); 310 int r; 311 312 priv->baud_rate = DEFAULT_BAUD_RATE; 313 314 r = ch341_configure(serial->dev, priv); 315 if (r) 316 goto out; 317 318 r = ch341_set_handshake(serial->dev, priv->line_control); 319 if (r) 320 goto out; 321 322 r = ch341_set_baudrate(serial->dev, priv); 323 if (r) 324 goto out; 325 326 dev_dbg(&port->dev, "%s - submitting interrupt urb\n", __func__); 327 r = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL); 328 if (r) { 329 dev_err(&port->dev, "%s - failed to submit interrupt urb: %d\n", 330 __func__, r); 331 ch341_close(port); 332 goto out; 333 } 334 335 r = usb_serial_generic_open(tty, port); 336 337 out: return r; 338 } 339 340 /* Old_termios contains the original termios settings and 341 * tty->termios contains the new setting to be used. 342 */ 343 static void ch341_set_termios(struct tty_struct *tty, 344 struct usb_serial_port *port, struct ktermios *old_termios) 345 { 346 struct ch341_private *priv = usb_get_serial_port_data(port); 347 unsigned baud_rate; 348 unsigned long flags; 349 350 baud_rate = tty_get_baud_rate(tty); 351 352 priv->baud_rate = baud_rate; 353 354 if (baud_rate) { 355 spin_lock_irqsave(&priv->lock, flags); 356 priv->line_control |= (CH341_BIT_DTR | CH341_BIT_RTS); 357 spin_unlock_irqrestore(&priv->lock, flags); 358 ch341_set_baudrate(port->serial->dev, priv); 359 } else { 360 spin_lock_irqsave(&priv->lock, flags); 361 priv->line_control &= ~(CH341_BIT_DTR | CH341_BIT_RTS); 362 spin_unlock_irqrestore(&priv->lock, flags); 363 } 364 365 ch341_set_handshake(port->serial->dev, priv->line_control); 366 367 /* Unimplemented: 368 * (cflag & CSIZE) : data bits [5, 8] 369 * (cflag & PARENB) : parity {NONE, EVEN, ODD} 370 * (cflag & CSTOPB) : stop bits [1, 2] 371 */ 372 } 373 374 static void ch341_break_ctl(struct tty_struct *tty, int break_state) 375 { 376 const uint16_t ch341_break_reg = 377 CH341_REG_BREAK1 | ((uint16_t) CH341_REG_BREAK2 << 8); 378 struct usb_serial_port *port = tty->driver_data; 379 int r; 380 uint16_t reg_contents; 381 uint8_t *break_reg; 382 383 break_reg = kmalloc(2, GFP_KERNEL); 384 if (!break_reg) 385 return; 386 387 r = ch341_control_in(port->serial->dev, CH341_REQ_READ_REG, 388 ch341_break_reg, 0, break_reg, 2); 389 if (r < 0) { 390 dev_err(&port->dev, "%s - USB control read error (%d)\n", 391 __func__, r); 392 goto out; 393 } 394 dev_dbg(&port->dev, "%s - initial ch341 break register contents - reg1: %x, reg2: %x\n", 395 __func__, break_reg[0], break_reg[1]); 396 if (break_state != 0) { 397 dev_dbg(&port->dev, "%s - Enter break state requested\n", __func__); 398 break_reg[0] &= ~CH341_NBREAK_BITS_REG1; 399 break_reg[1] &= ~CH341_NBREAK_BITS_REG2; 400 } else { 401 dev_dbg(&port->dev, "%s - Leave break state requested\n", __func__); 402 break_reg[0] |= CH341_NBREAK_BITS_REG1; 403 break_reg[1] |= CH341_NBREAK_BITS_REG2; 404 } 405 dev_dbg(&port->dev, "%s - New ch341 break register contents - reg1: %x, reg2: %x\n", 406 __func__, break_reg[0], break_reg[1]); 407 reg_contents = get_unaligned_le16(break_reg); 408 r = ch341_control_out(port->serial->dev, CH341_REQ_WRITE_REG, 409 ch341_break_reg, reg_contents); 410 if (r < 0) 411 dev_err(&port->dev, "%s - USB control write error (%d)\n", 412 __func__, r); 413 out: 414 kfree(break_reg); 415 } 416 417 static int ch341_tiocmset(struct tty_struct *tty, 418 unsigned int set, unsigned int clear) 419 { 420 struct usb_serial_port *port = tty->driver_data; 421 struct ch341_private *priv = usb_get_serial_port_data(port); 422 unsigned long flags; 423 u8 control; 424 425 spin_lock_irqsave(&priv->lock, flags); 426 if (set & TIOCM_RTS) 427 priv->line_control |= CH341_BIT_RTS; 428 if (set & TIOCM_DTR) 429 priv->line_control |= CH341_BIT_DTR; 430 if (clear & TIOCM_RTS) 431 priv->line_control &= ~CH341_BIT_RTS; 432 if (clear & TIOCM_DTR) 433 priv->line_control &= ~CH341_BIT_DTR; 434 control = priv->line_control; 435 spin_unlock_irqrestore(&priv->lock, flags); 436 437 return ch341_set_handshake(port->serial->dev, control); 438 } 439 440 static void ch341_update_line_status(struct usb_serial_port *port, 441 unsigned char *data, size_t len) 442 { 443 struct ch341_private *priv = usb_get_serial_port_data(port); 444 struct tty_struct *tty; 445 unsigned long flags; 446 u8 status; 447 u8 delta; 448 449 if (len < 4) 450 return; 451 452 status = ~data[2] & CH341_BITS_MODEM_STAT; 453 454 spin_lock_irqsave(&priv->lock, flags); 455 delta = status ^ priv->line_status; 456 priv->line_status = status; 457 spin_unlock_irqrestore(&priv->lock, flags); 458 459 if (data[1] & CH341_MULT_STAT) 460 dev_dbg(&port->dev, "%s - multiple status change\n", __func__); 461 462 if (!delta) 463 return; 464 465 if (delta & CH341_BIT_CTS) 466 port->icount.cts++; 467 if (delta & CH341_BIT_DSR) 468 port->icount.dsr++; 469 if (delta & CH341_BIT_RI) 470 port->icount.rng++; 471 if (delta & CH341_BIT_DCD) { 472 port->icount.dcd++; 473 tty = tty_port_tty_get(&port->port); 474 if (tty) { 475 usb_serial_handle_dcd_change(port, tty, 476 status & CH341_BIT_DCD); 477 tty_kref_put(tty); 478 } 479 } 480 481 wake_up_interruptible(&port->port.delta_msr_wait); 482 } 483 484 static void ch341_read_int_callback(struct urb *urb) 485 { 486 struct usb_serial_port *port = urb->context; 487 unsigned char *data = urb->transfer_buffer; 488 unsigned int len = urb->actual_length; 489 int status; 490 491 switch (urb->status) { 492 case 0: 493 /* success */ 494 break; 495 case -ECONNRESET: 496 case -ENOENT: 497 case -ESHUTDOWN: 498 /* this urb is terminated, clean up */ 499 dev_dbg(&urb->dev->dev, "%s - urb shutting down: %d\n", 500 __func__, urb->status); 501 return; 502 default: 503 dev_dbg(&urb->dev->dev, "%s - nonzero urb status: %d\n", 504 __func__, urb->status); 505 goto exit; 506 } 507 508 usb_serial_debug_data(&port->dev, __func__, len, data); 509 ch341_update_line_status(port, data, len); 510 exit: 511 status = usb_submit_urb(urb, GFP_ATOMIC); 512 if (status) { 513 dev_err(&urb->dev->dev, "%s - usb_submit_urb failed: %d\n", 514 __func__, status); 515 } 516 } 517 518 static int ch341_tiocmget(struct tty_struct *tty) 519 { 520 struct usb_serial_port *port = tty->driver_data; 521 struct ch341_private *priv = usb_get_serial_port_data(port); 522 unsigned long flags; 523 u8 mcr; 524 u8 status; 525 unsigned int result; 526 527 spin_lock_irqsave(&priv->lock, flags); 528 mcr = priv->line_control; 529 status = priv->line_status; 530 spin_unlock_irqrestore(&priv->lock, flags); 531 532 result = ((mcr & CH341_BIT_DTR) ? TIOCM_DTR : 0) 533 | ((mcr & CH341_BIT_RTS) ? TIOCM_RTS : 0) 534 | ((status & CH341_BIT_CTS) ? TIOCM_CTS : 0) 535 | ((status & CH341_BIT_DSR) ? TIOCM_DSR : 0) 536 | ((status & CH341_BIT_RI) ? TIOCM_RI : 0) 537 | ((status & CH341_BIT_DCD) ? TIOCM_CD : 0); 538 539 dev_dbg(&port->dev, "%s - result = %x\n", __func__, result); 540 541 return result; 542 } 543 544 static int ch341_reset_resume(struct usb_serial *serial) 545 { 546 struct ch341_private *priv; 547 548 priv = usb_get_serial_port_data(serial->port[0]); 549 550 /* reconfigure ch341 serial port after bus-reset */ 551 ch341_configure(serial->dev, priv); 552 553 return 0; 554 } 555 556 static struct usb_serial_driver ch341_device = { 557 .driver = { 558 .owner = THIS_MODULE, 559 .name = "ch341-uart", 560 }, 561 .id_table = id_table, 562 .num_ports = 1, 563 .open = ch341_open, 564 .dtr_rts = ch341_dtr_rts, 565 .carrier_raised = ch341_carrier_raised, 566 .close = ch341_close, 567 .set_termios = ch341_set_termios, 568 .break_ctl = ch341_break_ctl, 569 .tiocmget = ch341_tiocmget, 570 .tiocmset = ch341_tiocmset, 571 .tiocmiwait = usb_serial_generic_tiocmiwait, 572 .read_int_callback = ch341_read_int_callback, 573 .port_probe = ch341_port_probe, 574 .port_remove = ch341_port_remove, 575 .reset_resume = ch341_reset_resume, 576 }; 577 578 static struct usb_serial_driver * const serial_drivers[] = { 579 &ch341_device, NULL 580 }; 581 582 module_usb_serial_driver(serial_drivers, id_table); 583 584 MODULE_LICENSE("GPL"); 585