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 void ch341_set_termios(struct tty_struct *tty, 88 struct usb_serial_port *port, 89 struct ktermios *old_termios); 90 91 static int ch341_control_out(struct usb_device *dev, u8 request, 92 u16 value, u16 index) 93 { 94 int r; 95 96 dev_dbg(&dev->dev, "ch341_control_out(%02x,%02x,%04x,%04x)\n", 97 USB_DIR_OUT|0x40, (int)request, (int)value, (int)index); 98 99 r = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), request, 100 USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT, 101 value, index, NULL, 0, DEFAULT_TIMEOUT); 102 103 return r; 104 } 105 106 static int ch341_control_in(struct usb_device *dev, 107 u8 request, u16 value, u16 index, 108 char *buf, unsigned bufsize) 109 { 110 int r; 111 112 dev_dbg(&dev->dev, "ch341_control_in(%02x,%02x,%04x,%04x,%p,%u)\n", 113 USB_DIR_IN|0x40, (int)request, (int)value, (int)index, buf, 114 (int)bufsize); 115 116 r = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), request, 117 USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN, 118 value, index, buf, bufsize, DEFAULT_TIMEOUT); 119 return r; 120 } 121 122 static int ch341_set_baudrate(struct usb_device *dev, 123 struct ch341_private *priv) 124 { 125 short a, b; 126 int r; 127 unsigned long factor; 128 short divisor; 129 130 if (!priv->baud_rate) 131 return -EINVAL; 132 factor = (CH341_BAUDBASE_FACTOR / priv->baud_rate); 133 divisor = CH341_BAUDBASE_DIVMAX; 134 135 while ((factor > 0xfff0) && divisor) { 136 factor >>= 3; 137 divisor--; 138 } 139 140 if (factor > 0xfff0) 141 return -EINVAL; 142 143 factor = 0x10000 - factor; 144 a = (factor & 0xff00) | divisor; 145 b = factor & 0xff; 146 147 r = ch341_control_out(dev, 0x9a, 0x1312, a); 148 if (!r) 149 r = ch341_control_out(dev, 0x9a, 0x0f2c, b); 150 151 return r; 152 } 153 154 static int ch341_set_handshake(struct usb_device *dev, u8 control) 155 { 156 return ch341_control_out(dev, 0xa4, ~control, 0); 157 } 158 159 static int ch341_get_status(struct usb_device *dev, struct ch341_private *priv) 160 { 161 char *buffer; 162 int r; 163 const unsigned size = 8; 164 unsigned long flags; 165 166 buffer = kmalloc(size, GFP_KERNEL); 167 if (!buffer) 168 return -ENOMEM; 169 170 r = ch341_control_in(dev, 0x95, 0x0706, 0, buffer, size); 171 if (r < 0) 172 goto out; 173 174 /* setup the private status if available */ 175 if (r == 2) { 176 r = 0; 177 spin_lock_irqsave(&priv->lock, flags); 178 priv->line_status = (~(*buffer)) & CH341_BITS_MODEM_STAT; 179 spin_unlock_irqrestore(&priv->lock, flags); 180 } else 181 r = -EPROTO; 182 183 out: kfree(buffer); 184 return r; 185 } 186 187 /* -------------------------------------------------------------------------- */ 188 189 static int ch341_configure(struct usb_device *dev, struct ch341_private *priv) 190 { 191 char *buffer; 192 int r; 193 const unsigned size = 8; 194 195 buffer = kmalloc(size, GFP_KERNEL); 196 if (!buffer) 197 return -ENOMEM; 198 199 /* expect two bytes 0x27 0x00 */ 200 r = ch341_control_in(dev, 0x5f, 0, 0, buffer, size); 201 if (r < 0) 202 goto out; 203 204 r = ch341_control_out(dev, 0xa1, 0, 0); 205 if (r < 0) 206 goto out; 207 208 r = ch341_set_baudrate(dev, priv); 209 if (r < 0) 210 goto out; 211 212 /* expect two bytes 0x56 0x00 */ 213 r = ch341_control_in(dev, 0x95, 0x2518, 0, buffer, size); 214 if (r < 0) 215 goto out; 216 217 r = ch341_control_out(dev, 0x9a, 0x2518, 0x0050); 218 if (r < 0) 219 goto out; 220 221 /* expect 0xff 0xee */ 222 r = ch341_get_status(dev, priv); 223 if (r < 0) 224 goto out; 225 226 r = ch341_control_out(dev, 0xa1, 0x501f, 0xd90a); 227 if (r < 0) 228 goto out; 229 230 r = ch341_set_baudrate(dev, priv); 231 if (r < 0) 232 goto out; 233 234 r = ch341_set_handshake(dev, priv->line_control); 235 if (r < 0) 236 goto out; 237 238 /* expect 0x9f 0xee */ 239 r = ch341_get_status(dev, priv); 240 241 out: kfree(buffer); 242 return r; 243 } 244 245 static int ch341_port_probe(struct usb_serial_port *port) 246 { 247 struct ch341_private *priv; 248 int r; 249 250 priv = kzalloc(sizeof(struct ch341_private), GFP_KERNEL); 251 if (!priv) 252 return -ENOMEM; 253 254 spin_lock_init(&priv->lock); 255 priv->baud_rate = DEFAULT_BAUD_RATE; 256 priv->line_control = CH341_BIT_RTS | CH341_BIT_DTR; 257 258 r = ch341_configure(port->serial->dev, priv); 259 if (r < 0) 260 goto error; 261 262 usb_set_serial_port_data(port, priv); 263 return 0; 264 265 error: kfree(priv); 266 return r; 267 } 268 269 static int ch341_port_remove(struct usb_serial_port *port) 270 { 271 struct ch341_private *priv; 272 273 priv = usb_get_serial_port_data(port); 274 kfree(priv); 275 276 return 0; 277 } 278 279 static int ch341_carrier_raised(struct usb_serial_port *port) 280 { 281 struct ch341_private *priv = usb_get_serial_port_data(port); 282 if (priv->line_status & CH341_BIT_DCD) 283 return 1; 284 return 0; 285 } 286 287 static void ch341_dtr_rts(struct usb_serial_port *port, int on) 288 { 289 struct ch341_private *priv = usb_get_serial_port_data(port); 290 unsigned long flags; 291 292 /* drop DTR and RTS */ 293 spin_lock_irqsave(&priv->lock, flags); 294 if (on) 295 priv->line_control |= CH341_BIT_RTS | CH341_BIT_DTR; 296 else 297 priv->line_control &= ~(CH341_BIT_RTS | CH341_BIT_DTR); 298 spin_unlock_irqrestore(&priv->lock, flags); 299 ch341_set_handshake(port->serial->dev, priv->line_control); 300 } 301 302 static void ch341_close(struct usb_serial_port *port) 303 { 304 usb_serial_generic_close(port); 305 usb_kill_urb(port->interrupt_in_urb); 306 } 307 308 309 /* open this device, set default parameters */ 310 static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port) 311 { 312 struct usb_serial *serial = port->serial; 313 struct ch341_private *priv = usb_get_serial_port_data(port); 314 int r; 315 316 r = ch341_configure(serial->dev, priv); 317 if (r) 318 goto out; 319 320 if (tty) 321 ch341_set_termios(tty, port, NULL); 322 323 dev_dbg(&port->dev, "%s - submitting interrupt urb\n", __func__); 324 r = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL); 325 if (r) { 326 dev_err(&port->dev, "%s - failed to submit interrupt urb: %d\n", 327 __func__, r); 328 goto out; 329 } 330 331 r = usb_serial_generic_open(tty, port); 332 333 out: return r; 334 } 335 336 /* Old_termios contains the original termios settings and 337 * tty->termios contains the new setting to be used. 338 */ 339 static void ch341_set_termios(struct tty_struct *tty, 340 struct usb_serial_port *port, struct ktermios *old_termios) 341 { 342 struct ch341_private *priv = usb_get_serial_port_data(port); 343 unsigned baud_rate; 344 unsigned long flags; 345 346 baud_rate = tty_get_baud_rate(tty); 347 348 priv->baud_rate = baud_rate; 349 350 if (baud_rate) { 351 spin_lock_irqsave(&priv->lock, flags); 352 priv->line_control |= (CH341_BIT_DTR | CH341_BIT_RTS); 353 spin_unlock_irqrestore(&priv->lock, flags); 354 ch341_set_baudrate(port->serial->dev, priv); 355 } else { 356 spin_lock_irqsave(&priv->lock, flags); 357 priv->line_control &= ~(CH341_BIT_DTR | CH341_BIT_RTS); 358 spin_unlock_irqrestore(&priv->lock, flags); 359 } 360 361 ch341_set_handshake(port->serial->dev, priv->line_control); 362 363 /* Unimplemented: 364 * (cflag & CSIZE) : data bits [5, 8] 365 * (cflag & PARENB) : parity {NONE, EVEN, ODD} 366 * (cflag & CSTOPB) : stop bits [1, 2] 367 */ 368 } 369 370 static void ch341_break_ctl(struct tty_struct *tty, int break_state) 371 { 372 const uint16_t ch341_break_reg = 373 ((uint16_t) CH341_REG_BREAK2 << 8) | CH341_REG_BREAK1; 374 struct usb_serial_port *port = tty->driver_data; 375 int r; 376 uint16_t reg_contents; 377 uint8_t *break_reg; 378 379 break_reg = kmalloc(2, GFP_KERNEL); 380 if (!break_reg) 381 return; 382 383 r = ch341_control_in(port->serial->dev, CH341_REQ_READ_REG, 384 ch341_break_reg, 0, break_reg, 2); 385 if (r < 0) { 386 dev_err(&port->dev, "%s - USB control read error (%d)\n", 387 __func__, r); 388 goto out; 389 } 390 dev_dbg(&port->dev, "%s - initial ch341 break register contents - reg1: %x, reg2: %x\n", 391 __func__, break_reg[0], break_reg[1]); 392 if (break_state != 0) { 393 dev_dbg(&port->dev, "%s - Enter break state requested\n", __func__); 394 break_reg[0] &= ~CH341_NBREAK_BITS_REG1; 395 break_reg[1] &= ~CH341_NBREAK_BITS_REG2; 396 } else { 397 dev_dbg(&port->dev, "%s - Leave break state requested\n", __func__); 398 break_reg[0] |= CH341_NBREAK_BITS_REG1; 399 break_reg[1] |= CH341_NBREAK_BITS_REG2; 400 } 401 dev_dbg(&port->dev, "%s - New ch341 break register contents - reg1: %x, reg2: %x\n", 402 __func__, break_reg[0], break_reg[1]); 403 reg_contents = get_unaligned_le16(break_reg); 404 r = ch341_control_out(port->serial->dev, CH341_REQ_WRITE_REG, 405 ch341_break_reg, reg_contents); 406 if (r < 0) 407 dev_err(&port->dev, "%s - USB control write error (%d)\n", 408 __func__, r); 409 out: 410 kfree(break_reg); 411 } 412 413 static int ch341_tiocmset(struct tty_struct *tty, 414 unsigned int set, unsigned int clear) 415 { 416 struct usb_serial_port *port = tty->driver_data; 417 struct ch341_private *priv = usb_get_serial_port_data(port); 418 unsigned long flags; 419 u8 control; 420 421 spin_lock_irqsave(&priv->lock, flags); 422 if (set & TIOCM_RTS) 423 priv->line_control |= CH341_BIT_RTS; 424 if (set & TIOCM_DTR) 425 priv->line_control |= CH341_BIT_DTR; 426 if (clear & TIOCM_RTS) 427 priv->line_control &= ~CH341_BIT_RTS; 428 if (clear & TIOCM_DTR) 429 priv->line_control &= ~CH341_BIT_DTR; 430 control = priv->line_control; 431 spin_unlock_irqrestore(&priv->lock, flags); 432 433 return ch341_set_handshake(port->serial->dev, control); 434 } 435 436 static void ch341_update_line_status(struct usb_serial_port *port, 437 unsigned char *data, size_t len) 438 { 439 struct ch341_private *priv = usb_get_serial_port_data(port); 440 struct tty_struct *tty; 441 unsigned long flags; 442 u8 status; 443 u8 delta; 444 445 if (len < 4) 446 return; 447 448 status = ~data[2] & CH341_BITS_MODEM_STAT; 449 450 spin_lock_irqsave(&priv->lock, flags); 451 delta = status ^ priv->line_status; 452 priv->line_status = status; 453 spin_unlock_irqrestore(&priv->lock, flags); 454 455 if (data[1] & CH341_MULT_STAT) 456 dev_dbg(&port->dev, "%s - multiple status change\n", __func__); 457 458 if (!delta) 459 return; 460 461 if (delta & CH341_BIT_CTS) 462 port->icount.cts++; 463 if (delta & CH341_BIT_DSR) 464 port->icount.dsr++; 465 if (delta & CH341_BIT_RI) 466 port->icount.rng++; 467 if (delta & CH341_BIT_DCD) { 468 port->icount.dcd++; 469 tty = tty_port_tty_get(&port->port); 470 if (tty) { 471 usb_serial_handle_dcd_change(port, tty, 472 status & CH341_BIT_DCD); 473 tty_kref_put(tty); 474 } 475 } 476 477 wake_up_interruptible(&port->port.delta_msr_wait); 478 } 479 480 static void ch341_read_int_callback(struct urb *urb) 481 { 482 struct usb_serial_port *port = urb->context; 483 unsigned char *data = urb->transfer_buffer; 484 unsigned int len = urb->actual_length; 485 int status; 486 487 switch (urb->status) { 488 case 0: 489 /* success */ 490 break; 491 case -ECONNRESET: 492 case -ENOENT: 493 case -ESHUTDOWN: 494 /* this urb is terminated, clean up */ 495 dev_dbg(&urb->dev->dev, "%s - urb shutting down: %d\n", 496 __func__, urb->status); 497 return; 498 default: 499 dev_dbg(&urb->dev->dev, "%s - nonzero urb status: %d\n", 500 __func__, urb->status); 501 goto exit; 502 } 503 504 usb_serial_debug_data(&port->dev, __func__, len, data); 505 ch341_update_line_status(port, data, len); 506 exit: 507 status = usb_submit_urb(urb, GFP_ATOMIC); 508 if (status) { 509 dev_err(&urb->dev->dev, "%s - usb_submit_urb failed: %d\n", 510 __func__, status); 511 } 512 } 513 514 static int ch341_tiocmget(struct tty_struct *tty) 515 { 516 struct usb_serial_port *port = tty->driver_data; 517 struct ch341_private *priv = usb_get_serial_port_data(port); 518 unsigned long flags; 519 u8 mcr; 520 u8 status; 521 unsigned int result; 522 523 spin_lock_irqsave(&priv->lock, flags); 524 mcr = priv->line_control; 525 status = priv->line_status; 526 spin_unlock_irqrestore(&priv->lock, flags); 527 528 result = ((mcr & CH341_BIT_DTR) ? TIOCM_DTR : 0) 529 | ((mcr & CH341_BIT_RTS) ? TIOCM_RTS : 0) 530 | ((status & CH341_BIT_CTS) ? TIOCM_CTS : 0) 531 | ((status & CH341_BIT_DSR) ? TIOCM_DSR : 0) 532 | ((status & CH341_BIT_RI) ? TIOCM_RI : 0) 533 | ((status & CH341_BIT_DCD) ? TIOCM_CD : 0); 534 535 dev_dbg(&port->dev, "%s - result = %x\n", __func__, result); 536 537 return result; 538 } 539 540 static int ch341_reset_resume(struct usb_serial *serial) 541 { 542 struct ch341_private *priv; 543 544 priv = usb_get_serial_port_data(serial->port[0]); 545 546 /* reconfigure ch341 serial port after bus-reset */ 547 ch341_configure(serial->dev, priv); 548 549 return 0; 550 } 551 552 static struct usb_serial_driver ch341_device = { 553 .driver = { 554 .owner = THIS_MODULE, 555 .name = "ch341-uart", 556 }, 557 .id_table = id_table, 558 .num_ports = 1, 559 .open = ch341_open, 560 .dtr_rts = ch341_dtr_rts, 561 .carrier_raised = ch341_carrier_raised, 562 .close = ch341_close, 563 .set_termios = ch341_set_termios, 564 .break_ctl = ch341_break_ctl, 565 .tiocmget = ch341_tiocmget, 566 .tiocmset = ch341_tiocmset, 567 .tiocmiwait = usb_serial_generic_tiocmiwait, 568 .read_int_callback = ch341_read_int_callback, 569 .port_probe = ch341_port_probe, 570 .port_remove = ch341_port_remove, 571 .reset_resume = ch341_reset_resume, 572 }; 573 574 static struct usb_serial_driver * const serial_drivers[] = { 575 &ch341_device, NULL 576 }; 577 578 module_usb_serial_driver(serial_drivers, id_table); 579 580 MODULE_LICENSE("GPL"); 581