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
75 static const struct usb_device_id id_table[] = {
76 { USB_DEVICE(0x4348, 0x5523) },
77 { USB_DEVICE(0x1a86, 0x7523) },
80 MODULE_DEVICE_TABLE(usb, id_table);
82 struct ch341_private {
83 spinlock_t lock; /* access lock */
84 wait_queue_head_t delta_msr_wait; /* wait queue for modem status */
85 unsigned baud_rate; /* set baud rate */
86 u8 line_control; /* set line control value RTS/DTR */
87 u8 line_status; /* active status of modem control inputs */
88 u8 multi_status_change; /* status changed multiple since last call */
91 static int ch341_control_out(struct usb_device *dev, u8 request,
95 dbg("ch341_control_out(%02x,%02x,%04x,%04x)", USB_DIR_OUT|0x40,
96 (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)
110 dbg("ch341_control_in(%02x,%02x,%04x,%04x,%p,%u)", USB_DIR_IN|0x40,
111 (int)request, (int)value, (int)index, buf, (int)bufsize);
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);
119 static int ch341_set_baudrate(struct usb_device *dev,
120 struct ch341_private *priv)
124 unsigned long factor;
127 dbg("ch341_set_baudrate(%d)", priv->baud_rate);
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 dbg("ch341_set_handshake(0x%02x)", control);
156 return ch341_control_out(dev, 0xa4, ~control, 0);
159 static int ch341_get_status(struct usb_device *dev, struct ch341_private *priv)
163 const unsigned size = 8;
166 dbg("ch341_get_status()");
168 buffer = kmalloc(size, GFP_KERNEL);
172 r = ch341_control_in(dev, 0x95, 0x0706, 0, buffer, size);
176 /* setup the private status if available */
179 spin_lock_irqsave(&priv->lock, flags);
180 priv->line_status = (~(*buffer)) & CH341_BITS_MODEM_STAT;
181 priv->multi_status_change = 0;
182 spin_unlock_irqrestore(&priv->lock, flags);
190 /* -------------------------------------------------------------------------- */
192 static int ch341_configure(struct usb_device *dev, struct ch341_private *priv)
196 const unsigned size = 8;
198 dbg("ch341_configure()");
200 buffer = kmalloc(size, GFP_KERNEL);
204 /* expect two bytes 0x27 0x00 */
205 r = ch341_control_in(dev, 0x5f, 0, 0, buffer, size);
209 r = ch341_control_out(dev, 0xa1, 0, 0);
213 r = ch341_set_baudrate(dev, priv);
217 /* expect two bytes 0x56 0x00 */
218 r = ch341_control_in(dev, 0x95, 0x2518, 0, buffer, size);
222 r = ch341_control_out(dev, 0x9a, 0x2518, 0x0050);
226 /* expect 0xff 0xee */
227 r = ch341_get_status(dev, priv);
231 r = ch341_control_out(dev, 0xa1, 0x501f, 0xd90a);
235 r = ch341_set_baudrate(dev, priv);
239 r = ch341_set_handshake(dev, priv->line_control);
243 /* expect 0x9f 0xee */
244 r = ch341_get_status(dev, priv);
250 /* allocate private data */
251 static int ch341_attach(struct usb_serial *serial)
253 struct ch341_private *priv;
256 dbg("ch341_attach()");
259 priv = kzalloc(sizeof(struct ch341_private), GFP_KERNEL);
263 spin_lock_init(&priv->lock);
264 init_waitqueue_head(&priv->delta_msr_wait);
265 priv->baud_rate = DEFAULT_BAUD_RATE;
266 priv->line_control = CH341_BIT_RTS | CH341_BIT_DTR;
268 r = ch341_configure(serial->dev, priv);
272 usb_set_serial_port_data(serial->port[0], priv);
279 static int ch341_carrier_raised(struct usb_serial_port *port)
281 struct ch341_private *priv = usb_get_serial_port_data(port);
282 if (priv->line_status & CH341_BIT_DCD)
287 static void ch341_dtr_rts(struct usb_serial_port *port, int on)
289 struct ch341_private *priv = usb_get_serial_port_data(port);
292 dbg("%s - port %d", __func__, port->number);
293 /* drop DTR and RTS */
294 spin_lock_irqsave(&priv->lock, flags);
296 priv->line_control |= CH341_BIT_RTS | CH341_BIT_DTR;
298 priv->line_control &= ~(CH341_BIT_RTS | CH341_BIT_DTR);
299 spin_unlock_irqrestore(&priv->lock, flags);
300 ch341_set_handshake(port->serial->dev, priv->line_control);
301 wake_up_interruptible(&priv->delta_msr_wait);
304 static void ch341_close(struct usb_serial_port *port)
306 dbg("%s - port %d", __func__, port->number);
308 usb_serial_generic_close(port);
309 usb_kill_urb(port->interrupt_in_urb);
313 /* open this device, set default parameters */
314 static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port)
316 struct usb_serial *serial = port->serial;
317 struct ch341_private *priv = usb_get_serial_port_data(serial->port[0]);
322 priv->baud_rate = DEFAULT_BAUD_RATE;
324 r = ch341_configure(serial->dev, priv);
328 r = ch341_set_handshake(serial->dev, priv->line_control);
332 r = ch341_set_baudrate(serial->dev, priv);
336 dbg("%s - submitting interrupt urb", __func__);
337 port->interrupt_in_urb->dev = serial->dev;
338 r = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
340 dev_err(&port->dev, "%s - failed submitting interrupt urb,"
341 " error %d\n", __func__, r);
346 r = usb_serial_generic_open(tty, port);
351 /* Old_termios contains the original termios settings and
352 * tty->termios contains the new setting to be used.
354 static void ch341_set_termios(struct tty_struct *tty,
355 struct usb_serial_port *port, struct ktermios *old_termios)
357 struct ch341_private *priv = usb_get_serial_port_data(port);
361 dbg("ch341_set_termios()");
363 baud_rate = tty_get_baud_rate(tty);
365 priv->baud_rate = baud_rate;
368 spin_lock_irqsave(&priv->lock, flags);
369 priv->line_control |= (CH341_BIT_DTR | CH341_BIT_RTS);
370 spin_unlock_irqrestore(&priv->lock, flags);
371 ch341_set_baudrate(port->serial->dev, priv);
373 spin_lock_irqsave(&priv->lock, flags);
374 priv->line_control &= ~(CH341_BIT_DTR | CH341_BIT_RTS);
375 spin_unlock_irqrestore(&priv->lock, flags);
378 ch341_set_handshake(port->serial->dev, priv->line_control);
381 * (cflag & CSIZE) : data bits [5, 8]
382 * (cflag & PARENB) : parity {NONE, EVEN, ODD}
383 * (cflag & CSTOPB) : stop bits [1, 2]
387 static void ch341_break_ctl(struct tty_struct *tty, int break_state)
389 const uint16_t ch341_break_reg =
390 CH341_REG_BREAK1 | ((uint16_t) CH341_REG_BREAK2 << 8);
391 struct usb_serial_port *port = tty->driver_data;
393 uint16_t reg_contents;
396 dbg("%s()", __func__);
398 break_reg = kmalloc(2, GFP_KERNEL);
400 dev_err(&port->dev, "%s - kmalloc failed\n", __func__);
404 r = ch341_control_in(port->serial->dev, CH341_REQ_READ_REG,
405 ch341_break_reg, 0, break_reg, 2);
407 dev_err(&port->dev, "%s - USB control read error (%d)\n",
411 dbg("%s - initial ch341 break register contents - reg1: %x, reg2: %x",
412 __func__, break_reg[0], break_reg[1]);
413 if (break_state != 0) {
414 dbg("%s - Enter break state requested", __func__);
415 break_reg[0] &= ~CH341_NBREAK_BITS_REG1;
416 break_reg[1] &= ~CH341_NBREAK_BITS_REG2;
418 dbg("%s - Leave break state requested", __func__);
419 break_reg[0] |= CH341_NBREAK_BITS_REG1;
420 break_reg[1] |= CH341_NBREAK_BITS_REG2;
422 dbg("%s - New ch341 break register contents - reg1: %x, reg2: %x",
423 __func__, break_reg[0], break_reg[1]);
424 reg_contents = get_unaligned_le16(break_reg);
425 r = ch341_control_out(port->serial->dev, CH341_REQ_WRITE_REG,
426 ch341_break_reg, reg_contents);
428 dev_err(&port->dev, "%s - USB control write error (%d)\n",
434 static int ch341_tiocmset(struct tty_struct *tty,
435 unsigned int set, unsigned int clear)
437 struct usb_serial_port *port = tty->driver_data;
438 struct ch341_private *priv = usb_get_serial_port_data(port);
442 spin_lock_irqsave(&priv->lock, flags);
444 priv->line_control |= CH341_BIT_RTS;
446 priv->line_control |= CH341_BIT_DTR;
447 if (clear & TIOCM_RTS)
448 priv->line_control &= ~CH341_BIT_RTS;
449 if (clear & TIOCM_DTR)
450 priv->line_control &= ~CH341_BIT_DTR;
451 control = priv->line_control;
452 spin_unlock_irqrestore(&priv->lock, flags);
454 return ch341_set_handshake(port->serial->dev, control);
457 static void ch341_read_int_callback(struct urb *urb)
459 struct usb_serial_port *port = (struct usb_serial_port *) urb->context;
460 unsigned char *data = urb->transfer_buffer;
461 unsigned int actual_length = urb->actual_length;
464 dbg("%s (%d)", __func__, port->number);
466 switch (urb->status) {
473 /* this urb is terminated, clean up */
474 dbg("%s - urb shutting down with status: %d", __func__,
478 dbg("%s - nonzero urb status received: %d", __func__,
483 usb_serial_debug_data(debug, &port->dev, __func__,
484 urb->actual_length, urb->transfer_buffer);
486 if (actual_length >= 4) {
487 struct ch341_private *priv = usb_get_serial_port_data(port);
489 u8 prev_line_status = priv->line_status;
491 spin_lock_irqsave(&priv->lock, flags);
492 priv->line_status = (~(data[2])) & CH341_BITS_MODEM_STAT;
493 if ((data[1] & CH341_MULT_STAT))
494 priv->multi_status_change = 1;
495 spin_unlock_irqrestore(&priv->lock, flags);
497 if ((priv->line_status ^ prev_line_status) & CH341_BIT_DCD) {
498 struct tty_struct *tty = tty_port_tty_get(&port->port);
500 usb_serial_handle_dcd_change(port, tty,
501 priv->line_status & CH341_BIT_DCD);
505 wake_up_interruptible(&priv->delta_msr_wait);
509 status = usb_submit_urb(urb, GFP_ATOMIC);
511 dev_err(&urb->dev->dev,
512 "%s - usb_submit_urb failed with result %d\n",
516 static int wait_modem_info(struct usb_serial_port *port, unsigned int arg)
518 struct ch341_private *priv = usb_get_serial_port_data(port);
525 spin_lock_irqsave(&priv->lock, flags);
526 prevstatus = priv->line_status;
527 priv->multi_status_change = 0;
528 spin_unlock_irqrestore(&priv->lock, flags);
530 while (!multi_change) {
531 interruptible_sleep_on(&priv->delta_msr_wait);
532 /* see if a signal did it */
533 if (signal_pending(current))
536 spin_lock_irqsave(&priv->lock, flags);
537 status = priv->line_status;
538 multi_change = priv->multi_status_change;
539 spin_unlock_irqrestore(&priv->lock, flags);
541 changed = prevstatus ^ status;
543 if (((arg & TIOCM_RNG) && (changed & CH341_BIT_RI)) ||
544 ((arg & TIOCM_DSR) && (changed & CH341_BIT_DSR)) ||
545 ((arg & TIOCM_CD) && (changed & CH341_BIT_DCD)) ||
546 ((arg & TIOCM_CTS) && (changed & CH341_BIT_CTS))) {
555 static int ch341_ioctl(struct tty_struct *tty,
556 unsigned int cmd, unsigned long arg)
558 struct usb_serial_port *port = tty->driver_data;
559 dbg("%s (%d) cmd = 0x%04x", __func__, port->number, cmd);
563 dbg("%s (%d) TIOCMIWAIT", __func__, port->number);
564 return wait_modem_info(port, arg);
567 dbg("%s not supported = 0x%04x", __func__, cmd);
574 static int ch341_tiocmget(struct tty_struct *tty)
576 struct usb_serial_port *port = tty->driver_data;
577 struct ch341_private *priv = usb_get_serial_port_data(port);
583 dbg("%s (%d)", __func__, port->number);
585 spin_lock_irqsave(&priv->lock, flags);
586 mcr = priv->line_control;
587 status = priv->line_status;
588 spin_unlock_irqrestore(&priv->lock, flags);
590 result = ((mcr & CH341_BIT_DTR) ? TIOCM_DTR : 0)
591 | ((mcr & CH341_BIT_RTS) ? TIOCM_RTS : 0)
592 | ((status & CH341_BIT_CTS) ? TIOCM_CTS : 0)
593 | ((status & CH341_BIT_DSR) ? TIOCM_DSR : 0)
594 | ((status & CH341_BIT_RI) ? TIOCM_RI : 0)
595 | ((status & CH341_BIT_DCD) ? TIOCM_CD : 0);
597 dbg("%s - result = %x", __func__, result);
603 static int ch341_reset_resume(struct usb_interface *intf)
605 struct usb_device *dev = interface_to_usbdev(intf);
606 struct usb_serial *serial = NULL;
607 struct ch341_private *priv;
609 serial = usb_get_intfdata(intf);
610 priv = usb_get_serial_port_data(serial->port[0]);
612 /*reconfigure ch341 serial port after bus-reset*/
613 ch341_configure(dev, priv);
615 usb_serial_resume(intf);
620 static struct usb_driver ch341_driver = {
622 .probe = usb_serial_probe,
623 .disconnect = usb_serial_disconnect,
624 .suspend = usb_serial_suspend,
625 .resume = usb_serial_resume,
626 .reset_resume = ch341_reset_resume,
627 .id_table = id_table,
629 .supports_autosuspend = 1,
632 static struct usb_serial_driver ch341_device = {
634 .owner = THIS_MODULE,
635 .name = "ch341-uart",
637 .id_table = id_table,
638 .usb_driver = &ch341_driver,
641 .dtr_rts = ch341_dtr_rts,
642 .carrier_raised = ch341_carrier_raised,
643 .close = ch341_close,
644 .ioctl = ch341_ioctl,
645 .set_termios = ch341_set_termios,
646 .break_ctl = ch341_break_ctl,
647 .tiocmget = ch341_tiocmget,
648 .tiocmset = ch341_tiocmset,
649 .read_int_callback = ch341_read_int_callback,
650 .attach = ch341_attach,
653 static int __init ch341_init(void)
657 retval = usb_serial_register(&ch341_device);
660 retval = usb_register(&ch341_driver);
662 usb_serial_deregister(&ch341_device);
666 static void __exit ch341_exit(void)
668 usb_deregister(&ch341_driver);
669 usb_serial_deregister(&ch341_device);
672 module_init(ch341_init);
673 module_exit(ch341_exit);
674 MODULE_LICENSE("GPL");
676 module_param(debug, bool, S_IRUGO | S_IWUSR);
677 MODULE_PARM_DESC(debug, "Debug enabled or not");