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_READ_VERSION 0x5F
66 #define CH341_REQ_WRITE_REG 0x9A
67 #define CH341_REQ_READ_REG 0x95
68 #define CH341_REQ_SERIAL_INIT 0xA1
69 #define CH341_REQ_MODEM_CTRL 0xA4
71 #define CH341_REG_BREAK 0x05
72 #define CH341_REG_LCR 0x18
73 #define CH341_NBREAK_BITS 0x01
75 #define CH341_LCR_ENABLE_RX 0x80
76 #define CH341_LCR_ENABLE_TX 0x40
77 #define CH341_LCR_MARK_SPACE 0x20
78 #define CH341_LCR_PAR_EVEN 0x10
79 #define CH341_LCR_ENABLE_PAR 0x08
80 #define CH341_LCR_STOP_BITS_2 0x04
81 #define CH341_LCR_CS8 0x03
82 #define CH341_LCR_CS7 0x02
83 #define CH341_LCR_CS6 0x01
84 #define CH341_LCR_CS5 0x00
88 static const struct usb_device_id id_table[] = {
89 { USB_DEVICE(0x4348, 0x5523) },
90 { USB_DEVICE(0x1a86, 0x7523) },
91 { USB_DEVICE(0x1a86, 0x5523) },
94 MODULE_DEVICE_TABLE(usb, id_table);
96 struct ch341_private {
97 spinlock_t lock; /* access lock */
98 unsigned baud_rate; /* set baud rate */
99 u8 line_control; /* set line control value RTS/DTR */
100 u8 line_status; /* active status of modem control inputs */
101 u8 multi_status_change; /* status changed multiple since last call */
104 static void ch341_set_termios(struct tty_struct *tty,
105 struct usb_serial_port *port,
106 struct ktermios *old_termios);
108 static int ch341_control_out(struct usb_device *dev, u8 request,
109 u16 value, u16 index)
112 dbg("ch341_control_out(%02x,%02x,%04x,%04x)", USB_DIR_OUT|0x40,
113 (int)request, (int)value, (int)index);
115 r = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), request,
116 USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT,
117 value, index, NULL, 0, DEFAULT_TIMEOUT);
122 static int ch341_control_in(struct usb_device *dev,
123 u8 request, u16 value, u16 index,
124 char *buf, unsigned bufsize)
127 dbg("ch341_control_in(%02x,%02x,%04x,%04x,%p,%u)", USB_DIR_IN|0x40,
128 (int)request, (int)value, (int)index, buf, (int)bufsize);
130 r = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), request,
131 USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
132 value, index, buf, bufsize, DEFAULT_TIMEOUT);
136 static int ch341_init_set_baudrate(struct usb_device *dev,
137 struct ch341_private *priv, unsigned ctrl)
141 unsigned long factor;
144 dbg("ch341_set_baudrate(%d)", priv->baud_rate);
146 if (!priv->baud_rate)
148 factor = (CH341_BAUDBASE_FACTOR / priv->baud_rate);
149 divisor = CH341_BAUDBASE_DIVMAX;
151 while ((factor > 0xfff0) && divisor) {
159 factor = 0x10000 - factor;
160 a = (factor & 0xff00) | divisor;
162 /* 0x9c is "enable SFR_UART Control register and timer" */
163 r = ch341_control_out(dev, CH341_REQ_SERIAL_INIT,
164 0x9c | (ctrl << 8), a | 0x80);
169 static int ch341_set_handshake(struct usb_device *dev, u8 control)
171 dbg("ch341_set_handshake(0x%02x)", control);
172 return ch341_control_out(dev, CH341_REQ_MODEM_CTRL, ~control, 0);
175 static int ch341_get_status(struct usb_device *dev, struct ch341_private *priv)
179 const unsigned size = 8;
182 dbg("ch341_get_status()");
184 buffer = kmalloc(size, GFP_KERNEL);
188 r = ch341_control_in(dev, CH341_REQ_READ_REG, 0x0706, 0, buffer, size);
192 /* setup the private status if available */
195 spin_lock_irqsave(&priv->lock, flags);
196 priv->line_status = (~(*buffer)) & CH341_BITS_MODEM_STAT;
197 priv->multi_status_change = 0;
198 spin_unlock_irqrestore(&priv->lock, flags);
206 /* -------------------------------------------------------------------------- */
208 static int ch341_configure(struct usb_device *dev, struct ch341_private *priv)
212 const unsigned size = 8;
214 dbg("ch341_configure()");
216 buffer = kmalloc(size, GFP_KERNEL);
220 /* expect two bytes 0x27 0x00 */
221 r = ch341_control_in(dev, CH341_REQ_READ_VERSION, 0, 0, buffer, size);
225 r = ch341_control_out(dev, CH341_REQ_SERIAL_INIT, 0, 0);
229 /* expect two bytes 0x56 0x00 */
230 r = ch341_control_in(dev, CH341_REQ_READ_REG, 0x2518, 0, buffer, size);
234 r = ch341_control_out(dev, CH341_REQ_WRITE_REG, 0x2518, 0x0050);
238 /* expect 0xff 0xee */
239 r = ch341_get_status(dev, priv);
243 r = ch341_init_set_baudrate(dev, priv, 0);
247 r = ch341_set_handshake(dev, priv->line_control);
251 /* expect 0x9f 0xee */
252 r = ch341_get_status(dev, priv);
258 /* allocate private data */
259 static int ch341_attach(struct usb_serial *serial)
261 struct ch341_private *priv;
264 dbg("ch341_attach()");
267 priv = kzalloc(sizeof(struct ch341_private), GFP_KERNEL);
271 spin_lock_init(&priv->lock);
272 priv->baud_rate = DEFAULT_BAUD_RATE;
274 r = ch341_configure(serial->dev, priv);
278 usb_set_serial_port_data(serial->port[0], priv);
285 static int ch341_carrier_raised(struct usb_serial_port *port)
287 struct ch341_private *priv = usb_get_serial_port_data(port);
288 if (priv->line_status & CH341_BIT_DCD)
293 static void ch341_dtr_rts(struct usb_serial_port *port, int on)
295 struct ch341_private *priv = usb_get_serial_port_data(port);
298 dbg("%s - port %d", __func__, port->number);
299 /* drop DTR and RTS */
300 spin_lock_irqsave(&priv->lock, flags);
302 priv->line_control |= CH341_BIT_RTS | CH341_BIT_DTR;
304 priv->line_control &= ~(CH341_BIT_RTS | CH341_BIT_DTR);
305 spin_unlock_irqrestore(&priv->lock, flags);
306 ch341_set_handshake(port->serial->dev, priv->line_control);
307 wake_up_interruptible(&port->delta_msr_wait);
310 static void ch341_close(struct usb_serial_port *port)
312 dbg("%s - port %d", __func__, port->number);
314 usb_serial_generic_close(port);
315 usb_kill_urb(port->interrupt_in_urb);
319 /* open this device, set default parameters */
320 static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port)
322 struct usb_serial *serial = port->serial;
323 struct ch341_private *priv = usb_get_serial_port_data(serial->port[0]);
328 r = ch341_configure(serial->dev, priv);
333 ch341_set_termios(tty, port, NULL);
335 dbg("%s - submitting interrupt urb", __func__);
336 port->interrupt_in_urb->dev = serial->dev;
337 r = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
339 dev_err(&port->dev, "%s - failed submitting interrupt urb,"
340 " error %d\n", __func__, r);
344 r = usb_serial_generic_open(tty, port);
349 /* Old_termios contains the original termios settings and
350 * tty->termios contains the new setting to be used.
352 static void ch341_set_termios(struct tty_struct *tty,
353 struct usb_serial_port *port, struct ktermios *old_termios)
355 struct ch341_private *priv = usb_get_serial_port_data(port);
361 /* redundant changes may cause the chip to lose bytes */
362 if (old_termios && !tty_termios_hw_change(tty->termios, old_termios))
365 dbg("ch341_set_termios()");
367 baud_rate = tty_get_baud_rate(tty);
369 ctrl = CH341_LCR_ENABLE_RX | CH341_LCR_ENABLE_TX | CH341_LCR_CS8;
372 priv->baud_rate = baud_rate;
374 r = ch341_init_set_baudrate(port->serial->dev, priv, ctrl);
375 if (r < 0 && old_termios) {
376 priv->baud_rate = tty_termios_baud_rate(old_termios);
377 tty_termios_copy_hw(tty->termios, old_termios);
381 spin_lock_irqsave(&priv->lock, flags);
382 if (C_BAUD(tty) == B0)
383 priv->line_control &= ~(CH341_BIT_DTR | CH341_BIT_RTS);
384 else if (old_termios && (old_termios->c_cflag & CBAUD) == B0)
385 priv->line_control |= (CH341_BIT_DTR | CH341_BIT_RTS);
386 spin_unlock_irqrestore(&priv->lock, flags);
389 * (cflag & CSIZE) : data bits [5, 8]
390 * (cflag & PARENB) : parity {NONE, EVEN, ODD}
391 * (cflag & CSTOPB) : stop bits [1, 2]
395 static void ch341_break_ctl(struct tty_struct *tty, int break_state)
397 const uint16_t ch341_break_reg =
398 ((uint16_t) CH341_REG_LCR << 8) | CH341_REG_BREAK;
399 struct usb_serial_port *port = tty->driver_data;
401 uint16_t reg_contents;
404 dbg("%s()", __func__);
406 break_reg = kmalloc(2, GFP_KERNEL);
408 dev_err(&port->dev, "%s - kmalloc failed\n", __func__);
412 r = ch341_control_in(port->serial->dev, CH341_REQ_READ_REG,
413 ch341_break_reg, 0, break_reg, 2);
415 dev_err(&port->dev, "%s - USB control read error (%d)\n",
419 dbg("%s - initial ch341 break register contents - reg1: %x, reg2: %x",
420 __func__, break_reg[0], break_reg[1]);
421 if (break_state != 0) {
422 dbg("%s - Enter break state requested", __func__);
423 break_reg[0] &= ~CH341_NBREAK_BITS;
424 break_reg[1] &= ~CH341_LCR_ENABLE_TX;
426 dbg("%s - Leave break state requested", __func__);
427 break_reg[0] |= CH341_NBREAK_BITS;
428 break_reg[1] |= CH341_LCR_ENABLE_TX;
430 dbg("%s - New ch341 break register contents - reg1: %x, reg2: %x",
431 __func__, break_reg[0], break_reg[1]);
432 reg_contents = get_unaligned_le16(break_reg);
433 r = ch341_control_out(port->serial->dev, CH341_REQ_WRITE_REG,
434 ch341_break_reg, reg_contents);
436 dev_err(&port->dev, "%s - USB control write error (%d)\n",
442 static int ch341_tiocmset(struct tty_struct *tty,
443 unsigned int set, unsigned int clear)
445 struct usb_serial_port *port = tty->driver_data;
446 struct ch341_private *priv = usb_get_serial_port_data(port);
450 spin_lock_irqsave(&priv->lock, flags);
452 priv->line_control |= CH341_BIT_RTS;
454 priv->line_control |= CH341_BIT_DTR;
455 if (clear & TIOCM_RTS)
456 priv->line_control &= ~CH341_BIT_RTS;
457 if (clear & TIOCM_DTR)
458 priv->line_control &= ~CH341_BIT_DTR;
459 control = priv->line_control;
460 spin_unlock_irqrestore(&priv->lock, flags);
462 return ch341_set_handshake(port->serial->dev, control);
465 static void ch341_read_int_callback(struct urb *urb)
467 struct usb_serial_port *port = (struct usb_serial_port *) urb->context;
468 unsigned char *data = urb->transfer_buffer;
469 unsigned int actual_length = urb->actual_length;
472 dbg("%s (%d)", __func__, port->number);
474 switch (urb->status) {
481 /* this urb is terminated, clean up */
482 dbg("%s - urb shutting down with status: %d", __func__,
486 dbg("%s - nonzero urb status received: %d", __func__,
491 usb_serial_debug_data(debug, &port->dev, __func__,
492 urb->actual_length, urb->transfer_buffer);
494 if (actual_length >= 4) {
495 struct ch341_private *priv = usb_get_serial_port_data(port);
497 u8 prev_line_status = priv->line_status;
499 spin_lock_irqsave(&priv->lock, flags);
500 priv->line_status = (~(data[2])) & CH341_BITS_MODEM_STAT;
501 if ((data[1] & CH341_MULT_STAT))
502 priv->multi_status_change = 1;
503 spin_unlock_irqrestore(&priv->lock, flags);
505 if ((priv->line_status ^ prev_line_status) & CH341_BIT_DCD) {
506 struct tty_struct *tty = tty_port_tty_get(&port->port);
508 usb_serial_handle_dcd_change(port, tty,
509 priv->line_status & CH341_BIT_DCD);
513 wake_up_interruptible(&port->delta_msr_wait);
517 status = usb_submit_urb(urb, GFP_ATOMIC);
519 dev_err(&urb->dev->dev,
520 "%s - usb_submit_urb failed with result %d\n",
524 static int wait_modem_info(struct usb_serial_port *port, unsigned int arg)
526 struct ch341_private *priv = usb_get_serial_port_data(port);
533 spin_lock_irqsave(&priv->lock, flags);
534 prevstatus = priv->line_status;
535 priv->multi_status_change = 0;
536 spin_unlock_irqrestore(&priv->lock, flags);
538 while (!multi_change) {
539 interruptible_sleep_on(&port->delta_msr_wait);
540 /* see if a signal did it */
541 if (signal_pending(current))
544 if (port->serial->disconnected)
547 spin_lock_irqsave(&priv->lock, flags);
548 status = priv->line_status;
549 multi_change = priv->multi_status_change;
550 spin_unlock_irqrestore(&priv->lock, flags);
552 changed = prevstatus ^ status;
554 if (((arg & TIOCM_RNG) && (changed & CH341_BIT_RI)) ||
555 ((arg & TIOCM_DSR) && (changed & CH341_BIT_DSR)) ||
556 ((arg & TIOCM_CD) && (changed & CH341_BIT_DCD)) ||
557 ((arg & TIOCM_CTS) && (changed & CH341_BIT_CTS))) {
566 static int ch341_ioctl(struct tty_struct *tty,
567 unsigned int cmd, unsigned long arg)
569 struct usb_serial_port *port = tty->driver_data;
570 dbg("%s (%d) cmd = 0x%04x", __func__, port->number, cmd);
574 dbg("%s (%d) TIOCMIWAIT", __func__, port->number);
575 return wait_modem_info(port, arg);
578 dbg("%s not supported = 0x%04x", __func__, cmd);
585 static int ch341_tiocmget(struct tty_struct *tty)
587 struct usb_serial_port *port = tty->driver_data;
588 struct ch341_private *priv = usb_get_serial_port_data(port);
594 dbg("%s (%d)", __func__, port->number);
596 spin_lock_irqsave(&priv->lock, flags);
597 mcr = priv->line_control;
598 status = priv->line_status;
599 spin_unlock_irqrestore(&priv->lock, flags);
601 result = ((mcr & CH341_BIT_DTR) ? TIOCM_DTR : 0)
602 | ((mcr & CH341_BIT_RTS) ? TIOCM_RTS : 0)
603 | ((status & CH341_BIT_CTS) ? TIOCM_CTS : 0)
604 | ((status & CH341_BIT_DSR) ? TIOCM_DSR : 0)
605 | ((status & CH341_BIT_RI) ? TIOCM_RI : 0)
606 | ((status & CH341_BIT_DCD) ? TIOCM_CD : 0);
608 dbg("%s - result = %x", __func__, result);
614 static int ch341_reset_resume(struct usb_interface *intf)
616 struct usb_device *dev = interface_to_usbdev(intf);
617 struct usb_serial *serial = NULL;
618 struct ch341_private *priv;
620 serial = usb_get_intfdata(intf);
621 priv = usb_get_serial_port_data(serial->port[0]);
623 /*reconfigure ch341 serial port after bus-reset*/
624 ch341_configure(dev, priv);
626 usb_serial_resume(intf);
631 static struct usb_driver ch341_driver = {
633 .probe = usb_serial_probe,
634 .disconnect = usb_serial_disconnect,
635 .suspend = usb_serial_suspend,
636 .resume = usb_serial_resume,
637 .reset_resume = ch341_reset_resume,
638 .id_table = id_table,
640 .supports_autosuspend = 1,
643 static struct usb_serial_driver ch341_device = {
645 .owner = THIS_MODULE,
646 .name = "ch341-uart",
648 .id_table = id_table,
649 .usb_driver = &ch341_driver,
652 .dtr_rts = ch341_dtr_rts,
653 .carrier_raised = ch341_carrier_raised,
654 .close = ch341_close,
655 .ioctl = ch341_ioctl,
656 .set_termios = ch341_set_termios,
657 .break_ctl = ch341_break_ctl,
658 .tiocmget = ch341_tiocmget,
659 .tiocmset = ch341_tiocmset,
660 .read_int_callback = ch341_read_int_callback,
661 .attach = ch341_attach,
664 static int __init ch341_init(void)
668 retval = usb_serial_register(&ch341_device);
671 retval = usb_register(&ch341_driver);
673 usb_serial_deregister(&ch341_device);
677 static void __exit ch341_exit(void)
679 usb_deregister(&ch341_driver);
680 usb_serial_deregister(&ch341_device);
683 module_init(ch341_init);
684 module_exit(ch341_exit);
685 MODULE_LICENSE("GPL");
687 module_param(debug, bool, S_IRUGO | S_IWUSR);
688 MODULE_PARM_DESC(debug, "Debug enabled or not");