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/init.h> 20 #include <linux/tty.h> 21 #include <linux/module.h> 22 #include <linux/slab.h> 23 #include <linux/usb.h> 24 #include <linux/usb/serial.h> 25 #include <linux/serial.h> 26 #include <asm/unaligned.h> 27 28 #define DEFAULT_BAUD_RATE 9600 29 #define DEFAULT_TIMEOUT 1000 30 31 /* flags for IO-Bits */ 32 #define CH341_BIT_RTS (1 << 6) 33 #define CH341_BIT_DTR (1 << 5) 34 35 /******************************/ 36 /* interrupt pipe definitions */ 37 /******************************/ 38 /* always 4 interrupt bytes */ 39 /* first irq byte normally 0x08 */ 40 /* second irq byte base 0x7d + below */ 41 /* third irq byte base 0x94 + below */ 42 /* fourth irq byte normally 0xee */ 43 44 /* second interrupt byte */ 45 #define CH341_MULT_STAT 0x04 /* multiple status since last interrupt event */ 46 47 /* status returned in third interrupt answer byte, inverted in data 48 from irq */ 49 #define CH341_BIT_CTS 0x01 50 #define CH341_BIT_DSR 0x02 51 #define CH341_BIT_RI 0x04 52 #define CH341_BIT_DCD 0x08 53 #define CH341_BITS_MODEM_STAT 0x0f /* all bits */ 54 55 /*******************************/ 56 /* baudrate calculation factor */ 57 /*******************************/ 58 #define CH341_BAUDBASE_FACTOR 1532620800 59 #define CH341_BAUDBASE_DIVMAX 3 60 61 /* Break support - the information used to implement this was gleaned from 62 * the Net/FreeBSD uchcom.c driver by Takanori Watanabe. Domo arigato. 63 */ 64 65 #define CH341_REQ_WRITE_REG 0x9A 66 #define CH341_REQ_READ_REG 0x95 67 #define CH341_REG_BREAK1 0x05 68 #define CH341_REG_BREAK2 0x18 69 #define CH341_NBREAK_BITS_REG1 0x01 70 #define CH341_NBREAK_BITS_REG2 0x40 71 72 73 static const struct usb_device_id id_table[] = { 74 { USB_DEVICE(0x4348, 0x5523) }, 75 { USB_DEVICE(0x1a86, 0x7523) }, 76 { USB_DEVICE(0x1a86, 0x5523) }, 77 { }, 78 }; 79 MODULE_DEVICE_TABLE(usb, id_table); 80 81 struct ch341_private { 82 spinlock_t lock; /* access lock */ 83 unsigned baud_rate; /* set baud rate */ 84 u8 line_control; /* set line control value RTS/DTR */ 85 u8 line_status; /* active status of modem control inputs */ 86 }; 87 88 static int ch341_control_out(struct usb_device *dev, u8 request, 89 u16 value, u16 index) 90 { 91 int r; 92 93 dev_dbg(&dev->dev, "ch341_control_out(%02x,%02x,%04x,%04x)\n", 94 USB_DIR_OUT|0x40, (int)request, (int)value, (int)index); 95 96 r = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), request, 97 USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT, 98 value, index, NULL, 0, DEFAULT_TIMEOUT); 99 100 return r; 101 } 102 103 static int ch341_control_in(struct usb_device *dev, 104 u8 request, u16 value, u16 index, 105 char *buf, unsigned bufsize) 106 { 107 int r; 108 109 dev_dbg(&dev->dev, "ch341_control_in(%02x,%02x,%04x,%04x,%p,%u)\n", 110 USB_DIR_IN|0x40, (int)request, (int)value, (int)index, buf, 111 (int)bufsize); 112 113 r = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), request, 114 USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN, 115 value, index, buf, bufsize, DEFAULT_TIMEOUT); 116 return r; 117 } 118 119 static int ch341_set_baudrate(struct usb_device *dev, 120 struct ch341_private *priv) 121 { 122 short a, b; 123 int r; 124 unsigned long factor; 125 short divisor; 126 127 if (!priv->baud_rate) 128 return -EINVAL; 129 factor = (CH341_BAUDBASE_FACTOR / priv->baud_rate); 130 divisor = CH341_BAUDBASE_DIVMAX; 131 132 while ((factor > 0xfff0) && divisor) { 133 factor >>= 3; 134 divisor--; 135 } 136 137 if (factor > 0xfff0) 138 return -EINVAL; 139 140 factor = 0x10000 - factor; 141 a = (factor & 0xff00) | divisor; 142 b = factor & 0xff; 143 144 r = ch341_control_out(dev, 0x9a, 0x1312, a); 145 if (!r) 146 r = ch341_control_out(dev, 0x9a, 0x0f2c, b); 147 148 return r; 149 } 150 151 static int ch341_set_handshake(struct usb_device *dev, u8 control) 152 { 153 return ch341_control_out(dev, 0xa4, ~control, 0); 154 } 155 156 static int ch341_get_status(struct usb_device *dev, struct ch341_private *priv) 157 { 158 char *buffer; 159 int r; 160 const unsigned size = 8; 161 unsigned long flags; 162 163 buffer = kmalloc(size, GFP_KERNEL); 164 if (!buffer) 165 return -ENOMEM; 166 167 r = ch341_control_in(dev, 0x95, 0x0706, 0, buffer, size); 168 if (r < 0) 169 goto out; 170 171 /* setup the private status if available */ 172 if (r == 2) { 173 r = 0; 174 spin_lock_irqsave(&priv->lock, flags); 175 priv->line_status = (~(*buffer)) & CH341_BITS_MODEM_STAT; 176 spin_unlock_irqrestore(&priv->lock, flags); 177 } else 178 r = -EPROTO; 179 180 out: kfree(buffer); 181 return r; 182 } 183 184 /* -------------------------------------------------------------------------- */ 185 186 static int ch341_configure(struct usb_device *dev, struct ch341_private *priv) 187 { 188 char *buffer; 189 int r; 190 const unsigned size = 8; 191 192 buffer = kmalloc(size, GFP_KERNEL); 193 if (!buffer) 194 return -ENOMEM; 195 196 /* expect two bytes 0x27 0x00 */ 197 r = ch341_control_in(dev, 0x5f, 0, 0, buffer, size); 198 if (r < 0) 199 goto out; 200 201 r = ch341_control_out(dev, 0xa1, 0, 0); 202 if (r < 0) 203 goto out; 204 205 r = ch341_set_baudrate(dev, priv); 206 if (r < 0) 207 goto out; 208 209 /* expect two bytes 0x56 0x00 */ 210 r = ch341_control_in(dev, 0x95, 0x2518, 0, buffer, size); 211 if (r < 0) 212 goto out; 213 214 r = ch341_control_out(dev, 0x9a, 0x2518, 0x0050); 215 if (r < 0) 216 goto out; 217 218 /* expect 0xff 0xee */ 219 r = ch341_get_status(dev, priv); 220 if (r < 0) 221 goto out; 222 223 r = ch341_control_out(dev, 0xa1, 0x501f, 0xd90a); 224 if (r < 0) 225 goto out; 226 227 r = ch341_set_baudrate(dev, priv); 228 if (r < 0) 229 goto out; 230 231 r = ch341_set_handshake(dev, priv->line_control); 232 if (r < 0) 233 goto out; 234 235 /* expect 0x9f 0xee */ 236 r = ch341_get_status(dev, priv); 237 238 out: kfree(buffer); 239 return r; 240 } 241 242 static int ch341_port_probe(struct usb_serial_port *port) 243 { 244 struct ch341_private *priv; 245 int r; 246 247 priv = kzalloc(sizeof(struct ch341_private), GFP_KERNEL); 248 if (!priv) 249 return -ENOMEM; 250 251 spin_lock_init(&priv->lock); 252 priv->baud_rate = DEFAULT_BAUD_RATE; 253 priv->line_control = CH341_BIT_RTS | CH341_BIT_DTR; 254 255 r = ch341_configure(port->serial->dev, priv); 256 if (r < 0) 257 goto error; 258 259 usb_set_serial_port_data(port, priv); 260 return 0; 261 262 error: kfree(priv); 263 return r; 264 } 265 266 static int ch341_port_remove(struct usb_serial_port *port) 267 { 268 struct ch341_private *priv; 269 270 priv = usb_get_serial_port_data(port); 271 kfree(priv); 272 273 return 0; 274 } 275 276 static int ch341_carrier_raised(struct usb_serial_port *port) 277 { 278 struct ch341_private *priv = usb_get_serial_port_data(port); 279 if (priv->line_status & CH341_BIT_DCD) 280 return 1; 281 return 0; 282 } 283 284 static void ch341_dtr_rts(struct usb_serial_port *port, int on) 285 { 286 struct ch341_private *priv = usb_get_serial_port_data(port); 287 unsigned long flags; 288 289 /* drop DTR and RTS */ 290 spin_lock_irqsave(&priv->lock, flags); 291 if (on) 292 priv->line_control |= CH341_BIT_RTS | CH341_BIT_DTR; 293 else 294 priv->line_control &= ~(CH341_BIT_RTS | CH341_BIT_DTR); 295 spin_unlock_irqrestore(&priv->lock, flags); 296 ch341_set_handshake(port->serial->dev, priv->line_control); 297 } 298 299 static void ch341_close(struct usb_serial_port *port) 300 { 301 usb_serial_generic_close(port); 302 usb_kill_urb(port->interrupt_in_urb); 303 } 304 305 306 /* open this device, set default parameters */ 307 static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port) 308 { 309 struct usb_serial *serial = port->serial; 310 struct ch341_private *priv = usb_get_serial_port_data(port); 311 int r; 312 313 priv->baud_rate = DEFAULT_BAUD_RATE; 314 315 r = ch341_configure(serial->dev, priv); 316 if (r) 317 goto out; 318 319 r = ch341_set_handshake(serial->dev, priv->line_control); 320 if (r) 321 goto out; 322 323 r = ch341_set_baudrate(serial->dev, priv); 324 if (r) 325 goto out; 326 327 dev_dbg(&port->dev, "%s - submitting interrupt urb", __func__); 328 r = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL); 329 if (r) { 330 dev_err(&port->dev, "%s - failed submitting interrupt urb," 331 " error %d\n", __func__, r); 332 ch341_close(port); 333 goto out; 334 } 335 336 r = usb_serial_generic_open(tty, port); 337 338 out: return r; 339 } 340 341 /* Old_termios contains the original termios settings and 342 * tty->termios contains the new setting to be used. 343 */ 344 static void ch341_set_termios(struct tty_struct *tty, 345 struct usb_serial_port *port, struct ktermios *old_termios) 346 { 347 struct ch341_private *priv = usb_get_serial_port_data(port); 348 unsigned baud_rate; 349 unsigned long flags; 350 351 baud_rate = tty_get_baud_rate(tty); 352 353 priv->baud_rate = baud_rate; 354 355 if (baud_rate) { 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 ch341_set_baudrate(port->serial->dev, priv); 360 } else { 361 spin_lock_irqsave(&priv->lock, flags); 362 priv->line_control &= ~(CH341_BIT_DTR | CH341_BIT_RTS); 363 spin_unlock_irqrestore(&priv->lock, flags); 364 } 365 366 ch341_set_handshake(port->serial->dev, priv->line_control); 367 368 /* Unimplemented: 369 * (cflag & CSIZE) : data bits [5, 8] 370 * (cflag & PARENB) : parity {NONE, EVEN, ODD} 371 * (cflag & CSTOPB) : stop bits [1, 2] 372 */ 373 } 374 375 static void ch341_break_ctl(struct tty_struct *tty, int break_state) 376 { 377 const uint16_t ch341_break_reg = 378 CH341_REG_BREAK1 | ((uint16_t) CH341_REG_BREAK2 << 8); 379 struct usb_serial_port *port = tty->driver_data; 380 int r; 381 uint16_t reg_contents; 382 uint8_t *break_reg; 383 384 break_reg = kmalloc(2, GFP_KERNEL); 385 if (!break_reg) 386 return; 387 388 r = ch341_control_in(port->serial->dev, CH341_REQ_READ_REG, 389 ch341_break_reg, 0, break_reg, 2); 390 if (r < 0) { 391 dev_err(&port->dev, "%s - USB control read error (%d)\n", 392 __func__, r); 393 goto out; 394 } 395 dev_dbg(&port->dev, "%s - initial ch341 break register contents - reg1: %x, reg2: %x\n", 396 __func__, break_reg[0], break_reg[1]); 397 if (break_state != 0) { 398 dev_dbg(&port->dev, "%s - Enter break state requested\n", __func__); 399 break_reg[0] &= ~CH341_NBREAK_BITS_REG1; 400 break_reg[1] &= ~CH341_NBREAK_BITS_REG2; 401 } else { 402 dev_dbg(&port->dev, "%s - Leave break state requested\n", __func__); 403 break_reg[0] |= CH341_NBREAK_BITS_REG1; 404 break_reg[1] |= CH341_NBREAK_BITS_REG2; 405 } 406 dev_dbg(&port->dev, "%s - New ch341 break register contents - reg1: %x, reg2: %x\n", 407 __func__, break_reg[0], break_reg[1]); 408 reg_contents = get_unaligned_le16(break_reg); 409 r = ch341_control_out(port->serial->dev, CH341_REQ_WRITE_REG, 410 ch341_break_reg, reg_contents); 411 if (r < 0) 412 dev_err(&port->dev, "%s - USB control write error (%d)\n", 413 __func__, r); 414 out: 415 kfree(break_reg); 416 } 417 418 static int ch341_tiocmset(struct tty_struct *tty, 419 unsigned int set, unsigned int clear) 420 { 421 struct usb_serial_port *port = tty->driver_data; 422 struct ch341_private *priv = usb_get_serial_port_data(port); 423 unsigned long flags; 424 u8 control; 425 426 spin_lock_irqsave(&priv->lock, flags); 427 if (set & TIOCM_RTS) 428 priv->line_control |= CH341_BIT_RTS; 429 if (set & TIOCM_DTR) 430 priv->line_control |= CH341_BIT_DTR; 431 if (clear & TIOCM_RTS) 432 priv->line_control &= ~CH341_BIT_RTS; 433 if (clear & TIOCM_DTR) 434 priv->line_control &= ~CH341_BIT_DTR; 435 control = priv->line_control; 436 spin_unlock_irqrestore(&priv->lock, flags); 437 438 return ch341_set_handshake(port->serial->dev, control); 439 } 440 441 static void ch341_update_line_status(struct usb_serial_port *port, 442 unsigned char *data, size_t len) 443 { 444 struct ch341_private *priv = usb_get_serial_port_data(port); 445 struct tty_struct *tty; 446 unsigned long flags; 447 u8 status; 448 u8 delta; 449 450 if (len < 4) 451 return; 452 453 status = ~data[2] & CH341_BITS_MODEM_STAT; 454 455 spin_lock_irqsave(&priv->lock, flags); 456 delta = status ^ priv->line_status; 457 priv->line_status = status; 458 spin_unlock_irqrestore(&priv->lock, flags); 459 460 if (data[1] & CH341_MULT_STAT) 461 dev_dbg(&port->dev, "%s - multiple status change\n", __func__); 462 463 if (!delta) 464 return; 465 466 if (delta & CH341_BIT_CTS) 467 port->icount.cts++; 468 if (delta & CH341_BIT_DSR) 469 port->icount.dsr++; 470 if (delta & CH341_BIT_RI) 471 port->icount.rng++; 472 if (delta & CH341_BIT_DCD) { 473 port->icount.dcd++; 474 tty = tty_port_tty_get(&port->port); 475 if (tty) { 476 usb_serial_handle_dcd_change(port, tty, 477 status & CH341_BIT_DCD); 478 tty_kref_put(tty); 479 } 480 } 481 482 wake_up_interruptible(&port->port.delta_msr_wait); 483 } 484 485 static void ch341_read_int_callback(struct urb *urb) 486 { 487 struct usb_serial_port *port = urb->context; 488 unsigned char *data = urb->transfer_buffer; 489 unsigned int len = urb->actual_length; 490 int status; 491 492 switch (urb->status) { 493 case 0: 494 /* success */ 495 break; 496 case -ECONNRESET: 497 case -ENOENT: 498 case -ESHUTDOWN: 499 /* this urb is terminated, clean up */ 500 dev_dbg(&urb->dev->dev, "%s - urb shutting down: %d\n", 501 __func__, urb->status); 502 return; 503 default: 504 dev_dbg(&urb->dev->dev, "%s - nonzero urb status: %d\n", 505 __func__, urb->status); 506 goto exit; 507 } 508 509 usb_serial_debug_data(&port->dev, __func__, len, data); 510 ch341_update_line_status(port, data, len); 511 exit: 512 status = usb_submit_urb(urb, GFP_ATOMIC); 513 if (status) { 514 dev_err(&urb->dev->dev, "%s - usb_submit_urb failed: %d\n", 515 __func__, status); 516 } 517 } 518 519 static int ch341_tiocmget(struct tty_struct *tty) 520 { 521 struct usb_serial_port *port = tty->driver_data; 522 struct ch341_private *priv = usb_get_serial_port_data(port); 523 unsigned long flags; 524 u8 mcr; 525 u8 status; 526 unsigned int result; 527 528 spin_lock_irqsave(&priv->lock, flags); 529 mcr = priv->line_control; 530 status = priv->line_status; 531 spin_unlock_irqrestore(&priv->lock, flags); 532 533 result = ((mcr & CH341_BIT_DTR) ? TIOCM_DTR : 0) 534 | ((mcr & CH341_BIT_RTS) ? TIOCM_RTS : 0) 535 | ((status & CH341_BIT_CTS) ? TIOCM_CTS : 0) 536 | ((status & CH341_BIT_DSR) ? TIOCM_DSR : 0) 537 | ((status & CH341_BIT_RI) ? TIOCM_RI : 0) 538 | ((status & CH341_BIT_DCD) ? TIOCM_CD : 0); 539 540 dev_dbg(&port->dev, "%s - result = %x\n", __func__, result); 541 542 return result; 543 } 544 545 static int ch341_reset_resume(struct usb_serial *serial) 546 { 547 struct ch341_private *priv; 548 549 priv = usb_get_serial_port_data(serial->port[0]); 550 551 /* reconfigure ch341 serial port after bus-reset */ 552 ch341_configure(serial->dev, priv); 553 554 return 0; 555 } 556 557 static struct usb_serial_driver ch341_device = { 558 .driver = { 559 .owner = THIS_MODULE, 560 .name = "ch341-uart", 561 }, 562 .id_table = id_table, 563 .num_ports = 1, 564 .open = ch341_open, 565 .dtr_rts = ch341_dtr_rts, 566 .carrier_raised = ch341_carrier_raised, 567 .close = ch341_close, 568 .set_termios = ch341_set_termios, 569 .break_ctl = ch341_break_ctl, 570 .tiocmget = ch341_tiocmget, 571 .tiocmset = ch341_tiocmset, 572 .tiocmiwait = usb_serial_generic_tiocmiwait, 573 .read_int_callback = ch341_read_int_callback, 574 .port_probe = ch341_port_probe, 575 .port_remove = ch341_port_remove, 576 .reset_resume = ch341_reset_resume, 577 }; 578 579 static struct usb_serial_driver * const serial_drivers[] = { 580 &ch341_device, NULL 581 }; 582 583 module_usb_serial_driver(serial_drivers, id_table); 584 585 MODULE_LICENSE("GPL"); 586