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>
6 * ch341.c implements a serial port driver for the Winchiphead CH341.
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.
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.
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>
28 #define DEFAULT_BAUD_RATE 9600
29 #define DEFAULT_TIMEOUT 1000
31 /* flags for IO-Bits */
32 #define CH341_BIT_RTS (1 << 6)
33 #define CH341_BIT_DTR (1 << 5)
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 */
44 /* second interrupt byte */
45 #define CH341_MULT_STAT 0x04 /* multiple status since last interrupt event */
47 /* status returned in third interrupt answer byte, inverted in data
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 */
55 /*******************************/
56 /* baudrate calculation factor */
57 /*******************************/
58 #define CH341_BAUDBASE_FACTOR 1532620800
59 #define CH341_BAUDBASE_DIVMAX 3
61 /* Break support - the information used to implement this was gleaned from
62 * the Net/FreeBSD uchcom.c driver by Takanori Watanabe. Domo arigato.
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
73 static const struct usb_device_id id_table[] = {
74 { USB_DEVICE(0x4348, 0x5523) },
75 { USB_DEVICE(0x1a86, 0x7523) },
76 { USB_DEVICE(0x1a86, 0x5523) },
79 MODULE_DEVICE_TABLE(usb, id_table);
81 struct ch341_private {
82 spinlock_t lock; /* access lock */
83 wait_queue_head_t delta_msr_wait; /* wait queue for modem status */
84 unsigned baud_rate; /* set baud rate */
85 u8 line_control; /* set line control value RTS/DTR */
86 u8 line_status; /* active status of modem control inputs */
87 u8 multi_status_change; /* status changed multiple since last call */
90 static int ch341_control_out(struct usb_device *dev, u8 request,
95 dev_dbg(&dev->dev, "ch341_control_out(%02x,%02x,%04x,%04x)\n",
96 USB_DIR_OUT|0x40, (int)request, (int)value, (int)index);
98 r = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), request,
99 USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT,
100 value, index, NULL, 0, DEFAULT_TIMEOUT);
105 static int ch341_control_in(struct usb_device *dev,
106 u8 request, u16 value, u16 index,
107 char *buf, unsigned bufsize)
111 dev_dbg(&dev->dev, "ch341_control_in(%02x,%02x,%04x,%04x,%p,%u)\n",
112 USB_DIR_IN|0x40, (int)request, (int)value, (int)index, buf,
115 r = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), request,
116 USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
117 value, index, buf, bufsize, DEFAULT_TIMEOUT);
121 static int ch341_set_baudrate(struct usb_device *dev,
122 struct ch341_private *priv)
126 unsigned long factor;
129 if (!priv->baud_rate)
131 factor = (CH341_BAUDBASE_FACTOR / priv->baud_rate);
132 divisor = CH341_BAUDBASE_DIVMAX;
134 while ((factor > 0xfff0) && divisor) {
142 factor = 0x10000 - factor;
143 a = (factor & 0xff00) | divisor;
146 r = ch341_control_out(dev, 0x9a, 0x1312, a);
148 r = ch341_control_out(dev, 0x9a, 0x0f2c, b);
153 static int ch341_set_handshake(struct usb_device *dev, u8 control)
155 return ch341_control_out(dev, 0xa4, ~control, 0);
158 static int ch341_get_status(struct usb_device *dev, struct ch341_private *priv)
162 const unsigned size = 8;
165 buffer = kmalloc(size, GFP_KERNEL);
169 r = ch341_control_in(dev, 0x95, 0x0706, 0, buffer, size);
173 /* setup the private status if available */
176 spin_lock_irqsave(&priv->lock, flags);
177 priv->line_status = (~(*buffer)) & CH341_BITS_MODEM_STAT;
178 priv->multi_status_change = 0;
179 spin_unlock_irqrestore(&priv->lock, flags);
187 /* -------------------------------------------------------------------------- */
189 static int ch341_configure(struct usb_device *dev, struct ch341_private *priv)
193 const unsigned size = 8;
195 buffer = kmalloc(size, GFP_KERNEL);
199 /* expect two bytes 0x27 0x00 */
200 r = ch341_control_in(dev, 0x5f, 0, 0, buffer, size);
204 r = ch341_control_out(dev, 0xa1, 0, 0);
208 r = ch341_set_baudrate(dev, priv);
212 /* expect two bytes 0x56 0x00 */
213 r = ch341_control_in(dev, 0x95, 0x2518, 0, buffer, size);
217 r = ch341_control_out(dev, 0x9a, 0x2518, 0x0050);
221 /* expect 0xff 0xee */
222 r = ch341_get_status(dev, priv);
226 r = ch341_control_out(dev, 0xa1, 0x501f, 0xd90a);
230 r = ch341_set_baudrate(dev, priv);
234 r = ch341_set_handshake(dev, priv->line_control);
238 /* expect 0x9f 0xee */
239 r = ch341_get_status(dev, priv);
245 /* allocate private data */
246 static int ch341_attach(struct usb_serial *serial)
248 struct ch341_private *priv;
252 priv = kzalloc(sizeof(struct ch341_private), GFP_KERNEL);
256 spin_lock_init(&priv->lock);
257 init_waitqueue_head(&priv->delta_msr_wait);
258 priv->baud_rate = DEFAULT_BAUD_RATE;
259 priv->line_control = CH341_BIT_RTS | CH341_BIT_DTR;
261 r = ch341_configure(serial->dev, priv);
265 usb_set_serial_port_data(serial->port[0], priv);
272 static int ch341_carrier_raised(struct usb_serial_port *port)
274 struct ch341_private *priv = usb_get_serial_port_data(port);
275 if (priv->line_status & CH341_BIT_DCD)
280 static void ch341_dtr_rts(struct usb_serial_port *port, int on)
282 struct ch341_private *priv = usb_get_serial_port_data(port);
285 /* drop DTR and RTS */
286 spin_lock_irqsave(&priv->lock, flags);
288 priv->line_control |= CH341_BIT_RTS | CH341_BIT_DTR;
290 priv->line_control &= ~(CH341_BIT_RTS | CH341_BIT_DTR);
291 spin_unlock_irqrestore(&priv->lock, flags);
292 ch341_set_handshake(port->serial->dev, priv->line_control);
293 wake_up_interruptible(&priv->delta_msr_wait);
296 static void ch341_close(struct usb_serial_port *port)
298 usb_serial_generic_close(port);
299 usb_kill_urb(port->interrupt_in_urb);
303 /* open this device, set default parameters */
304 static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port)
306 struct usb_serial *serial = port->serial;
307 struct ch341_private *priv = usb_get_serial_port_data(serial->port[0]);
310 priv->baud_rate = DEFAULT_BAUD_RATE;
312 r = ch341_configure(serial->dev, priv);
316 r = ch341_set_handshake(serial->dev, priv->line_control);
320 r = ch341_set_baudrate(serial->dev, priv);
324 dev_dbg(&port->dev, "%s - submitting interrupt urb", __func__);
325 r = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
327 dev_err(&port->dev, "%s - failed submitting interrupt urb,"
328 " error %d\n", __func__, r);
333 r = usb_serial_generic_open(tty, port);
338 /* Old_termios contains the original termios settings and
339 * tty->termios contains the new setting to be used.
341 static void ch341_set_termios(struct tty_struct *tty,
342 struct usb_serial_port *port, struct ktermios *old_termios)
344 struct ch341_private *priv = usb_get_serial_port_data(port);
348 baud_rate = tty_get_baud_rate(tty);
350 priv->baud_rate = baud_rate;
353 spin_lock_irqsave(&priv->lock, flags);
354 priv->line_control |= (CH341_BIT_DTR | CH341_BIT_RTS);
355 spin_unlock_irqrestore(&priv->lock, flags);
356 ch341_set_baudrate(port->serial->dev, priv);
358 spin_lock_irqsave(&priv->lock, flags);
359 priv->line_control &= ~(CH341_BIT_DTR | CH341_BIT_RTS);
360 spin_unlock_irqrestore(&priv->lock, flags);
363 ch341_set_handshake(port->serial->dev, priv->line_control);
366 * (cflag & CSIZE) : data bits [5, 8]
367 * (cflag & PARENB) : parity {NONE, EVEN, ODD}
368 * (cflag & CSTOPB) : stop bits [1, 2]
372 static void ch341_break_ctl(struct tty_struct *tty, int break_state)
374 const uint16_t ch341_break_reg =
375 CH341_REG_BREAK1 | ((uint16_t) CH341_REG_BREAK2 << 8);
376 struct usb_serial_port *port = tty->driver_data;
378 uint16_t reg_contents;
381 break_reg = kmalloc(2, GFP_KERNEL);
383 dev_err(&port->dev, "%s - kmalloc failed\n", __func__);
387 r = ch341_control_in(port->serial->dev, CH341_REQ_READ_REG,
388 ch341_break_reg, 0, break_reg, 2);
390 dev_err(&port->dev, "%s - USB control read error (%d)\n",
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;
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;
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);
411 dev_err(&port->dev, "%s - USB control write error (%d)\n",
417 static int ch341_tiocmset(struct tty_struct *tty,
418 unsigned int set, unsigned int clear)
420 struct usb_serial_port *port = tty->driver_data;
421 struct ch341_private *priv = usb_get_serial_port_data(port);
425 spin_lock_irqsave(&priv->lock, flags);
427 priv->line_control |= CH341_BIT_RTS;
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);
437 return ch341_set_handshake(port->serial->dev, control);
440 static void ch341_read_int_callback(struct urb *urb)
442 struct usb_serial_port *port = (struct usb_serial_port *) urb->context;
443 unsigned char *data = urb->transfer_buffer;
444 unsigned int actual_length = urb->actual_length;
447 switch (urb->status) {
454 /* this urb is terminated, clean up */
455 dev_dbg(&urb->dev->dev, "%s - urb shutting down with status: %d\n",
456 __func__, urb->status);
459 dev_dbg(&urb->dev->dev, "%s - nonzero urb status received: %d\n",
460 __func__, urb->status);
464 usb_serial_debug_data(&port->dev, __func__,
465 urb->actual_length, urb->transfer_buffer);
467 if (actual_length >= 4) {
468 struct ch341_private *priv = usb_get_serial_port_data(port);
470 u8 prev_line_status = priv->line_status;
472 spin_lock_irqsave(&priv->lock, flags);
473 priv->line_status = (~(data[2])) & CH341_BITS_MODEM_STAT;
474 if ((data[1] & CH341_MULT_STAT))
475 priv->multi_status_change = 1;
476 spin_unlock_irqrestore(&priv->lock, flags);
478 if ((priv->line_status ^ prev_line_status) & CH341_BIT_DCD) {
479 struct tty_struct *tty = tty_port_tty_get(&port->port);
481 usb_serial_handle_dcd_change(port, tty,
482 priv->line_status & CH341_BIT_DCD);
486 wake_up_interruptible(&priv->delta_msr_wait);
490 status = usb_submit_urb(urb, GFP_ATOMIC);
492 dev_err(&urb->dev->dev,
493 "%s - usb_submit_urb failed with result %d\n",
497 static int wait_modem_info(struct usb_serial_port *port, unsigned int arg)
499 struct ch341_private *priv = usb_get_serial_port_data(port);
506 spin_lock_irqsave(&priv->lock, flags);
507 prevstatus = priv->line_status;
508 priv->multi_status_change = 0;
509 spin_unlock_irqrestore(&priv->lock, flags);
511 while (!multi_change) {
512 interruptible_sleep_on(&priv->delta_msr_wait);
513 /* see if a signal did it */
514 if (signal_pending(current))
517 spin_lock_irqsave(&priv->lock, flags);
518 status = priv->line_status;
519 multi_change = priv->multi_status_change;
520 spin_unlock_irqrestore(&priv->lock, flags);
522 changed = prevstatus ^ status;
524 if (((arg & TIOCM_RNG) && (changed & CH341_BIT_RI)) ||
525 ((arg & TIOCM_DSR) && (changed & CH341_BIT_DSR)) ||
526 ((arg & TIOCM_CD) && (changed & CH341_BIT_DCD)) ||
527 ((arg & TIOCM_CTS) && (changed & CH341_BIT_CTS))) {
536 static int ch341_ioctl(struct tty_struct *tty,
537 unsigned int cmd, unsigned long arg)
539 struct usb_serial_port *port = tty->driver_data;
541 dev_dbg(&port->dev, "%s (%d) cmd = 0x%04x\n", __func__, port->number, cmd);
545 dev_dbg(&port->dev, "%s (%d) TIOCMIWAIT\n", __func__, port->number);
546 return wait_modem_info(port, arg);
549 dev_dbg(&port->dev, "%s not supported = 0x%04x\n", __func__, cmd);
556 static int ch341_tiocmget(struct tty_struct *tty)
558 struct usb_serial_port *port = tty->driver_data;
559 struct ch341_private *priv = usb_get_serial_port_data(port);
565 spin_lock_irqsave(&priv->lock, flags);
566 mcr = priv->line_control;
567 status = priv->line_status;
568 spin_unlock_irqrestore(&priv->lock, flags);
570 result = ((mcr & CH341_BIT_DTR) ? TIOCM_DTR : 0)
571 | ((mcr & CH341_BIT_RTS) ? TIOCM_RTS : 0)
572 | ((status & CH341_BIT_CTS) ? TIOCM_CTS : 0)
573 | ((status & CH341_BIT_DSR) ? TIOCM_DSR : 0)
574 | ((status & CH341_BIT_RI) ? TIOCM_RI : 0)
575 | ((status & CH341_BIT_DCD) ? TIOCM_CD : 0);
577 dev_dbg(&port->dev, "%s - result = %x\n", __func__, result);
582 static int ch341_reset_resume(struct usb_serial *serial)
584 struct ch341_private *priv;
586 priv = usb_get_serial_port_data(serial->port[0]);
588 /* reconfigure ch341 serial port after bus-reset */
589 ch341_configure(serial->dev, priv);
594 static struct usb_serial_driver ch341_device = {
596 .owner = THIS_MODULE,
597 .name = "ch341-uart",
599 .id_table = id_table,
602 .dtr_rts = ch341_dtr_rts,
603 .carrier_raised = ch341_carrier_raised,
604 .close = ch341_close,
605 .ioctl = ch341_ioctl,
606 .set_termios = ch341_set_termios,
607 .break_ctl = ch341_break_ctl,
608 .tiocmget = ch341_tiocmget,
609 .tiocmset = ch341_tiocmset,
610 .read_int_callback = ch341_read_int_callback,
611 .attach = ch341_attach,
612 .reset_resume = ch341_reset_resume,
615 static struct usb_serial_driver * const serial_drivers[] = {
619 module_usb_serial_driver(serial_drivers, id_table);
621 MODULE_LICENSE("GPL");