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);
119 dev_err(&dev->dev, "failed to send control message: %d\n", r);
124 static int ch341_control_in(struct usb_device *dev,
125 u8 request, u16 value, u16 index,
126 char *buf, unsigned bufsize)
129 dbg("ch341_control_in(%02x,%02x,%04x,%04x,%p,%u)", USB_DIR_IN|0x40,
130 (int)request, (int)value, (int)index, buf, (int)bufsize);
132 r = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), request,
133 USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
134 value, index, buf, bufsize, DEFAULT_TIMEOUT);
138 "short control message received (%d < %u)\n",
143 dev_err(&dev->dev, "failed to receive control message: %d\n",
151 static int ch341_set_baudrate_lcr(struct usb_device *dev,
152 struct ch341_private *priv, u8 lcr)
156 unsigned long factor;
159 dbg("ch341_set_baudrate(%d)", priv->baud_rate);
161 if (!priv->baud_rate)
163 factor = (CH341_BAUDBASE_FACTOR / priv->baud_rate);
164 divisor = CH341_BAUDBASE_DIVMAX;
166 while ((factor > 0xfff0) && divisor) {
174 factor = 0x10000 - factor;
175 a = (factor & 0xff00) | divisor;
178 * CH341A buffers data until a full endpoint-size packet (32 bytes)
179 * has been received unless bit 7 is set.
183 r = ch341_control_out(dev, CH341_REQ_WRITE_REG, 0x1312, a);
187 r = ch341_control_out(dev, CH341_REQ_WRITE_REG, 0x2518, lcr);
194 static int ch341_set_handshake(struct usb_device *dev, u8 control)
196 dbg("ch341_set_handshake(0x%02x)", control);
197 return ch341_control_out(dev, CH341_REQ_MODEM_CTRL, ~control, 0);
200 static int ch341_get_status(struct usb_device *dev, struct ch341_private *priv)
202 const unsigned int size = 2;
207 dbg("ch341_get_status()");
209 buffer = kmalloc(size, GFP_KERNEL);
213 r = ch341_control_in(dev, CH341_REQ_READ_REG, 0x0706, 0, buffer, size);
217 spin_lock_irqsave(&priv->lock, flags);
218 priv->line_status = (~(*buffer)) & CH341_BITS_MODEM_STAT;
219 priv->multi_status_change = 0;
220 spin_unlock_irqrestore(&priv->lock, flags);
226 /* -------------------------------------------------------------------------- */
228 static int ch341_configure(struct usb_device *dev, struct ch341_private *priv)
230 const unsigned int size = 2;
234 dbg("ch341_configure()");
236 buffer = kmalloc(size, GFP_KERNEL);
240 /* expect two bytes 0x27 0x00 */
241 r = ch341_control_in(dev, CH341_REQ_READ_VERSION, 0, 0, buffer, size);
245 r = ch341_control_out(dev, CH341_REQ_SERIAL_INIT, 0, 0);
249 /* expect two bytes 0x56 0x00 */
250 r = ch341_control_in(dev, CH341_REQ_READ_REG, 0x2518, 0, buffer, size);
254 r = ch341_control_out(dev, CH341_REQ_WRITE_REG, 0x2518, 0x0050);
258 r = ch341_set_baudrate_lcr(dev, priv, 0);
262 r = ch341_set_handshake(dev, priv->line_control);
268 /* allocate private data */
269 static int ch341_attach(struct usb_serial *serial)
271 struct ch341_private *priv;
274 dbg("ch341_attach()");
277 priv = kzalloc(sizeof(struct ch341_private), GFP_KERNEL);
281 spin_lock_init(&priv->lock);
282 priv->baud_rate = DEFAULT_BAUD_RATE;
284 r = ch341_configure(serial->dev, priv);
288 usb_set_serial_port_data(serial->port[0], priv);
295 static int ch341_carrier_raised(struct usb_serial_port *port)
297 struct ch341_private *priv = usb_get_serial_port_data(port);
298 if (priv->line_status & CH341_BIT_DCD)
303 static void ch341_dtr_rts(struct usb_serial_port *port, int on)
305 struct ch341_private *priv = usb_get_serial_port_data(port);
308 dbg("%s - port %d", __func__, port->number);
309 /* drop DTR and RTS */
310 spin_lock_irqsave(&priv->lock, flags);
312 priv->line_control |= CH341_BIT_RTS | CH341_BIT_DTR;
314 priv->line_control &= ~(CH341_BIT_RTS | CH341_BIT_DTR);
315 spin_unlock_irqrestore(&priv->lock, flags);
316 ch341_set_handshake(port->serial->dev, priv->line_control);
317 wake_up_interruptible(&port->delta_msr_wait);
320 static void ch341_close(struct usb_serial_port *port)
322 dbg("%s - port %d", __func__, port->number);
324 usb_serial_generic_close(port);
325 usb_kill_urb(port->interrupt_in_urb);
329 /* open this device, set default parameters */
330 static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port)
332 struct usb_serial *serial = port->serial;
333 struct ch341_private *priv = usb_get_serial_port_data(serial->port[0]);
339 ch341_set_termios(tty, port, NULL);
341 dbg("%s - submitting interrupt urb", __func__);
342 port->interrupt_in_urb->dev = serial->dev;
343 r = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
345 dev_err(&port->dev, "%s - failed submitting interrupt urb,"
346 " error %d\n", __func__, r);
350 r = ch341_get_status(port->serial->dev, priv);
352 dev_err(&port->dev, "failed to read modem status: %d\n", r);
353 goto err_kill_interrupt_urb;
356 r = usb_serial_generic_open(tty, port);
358 goto err_kill_interrupt_urb;
362 err_kill_interrupt_urb:
363 usb_kill_urb(port->interrupt_in_urb);
368 /* Old_termios contains the original termios settings and
369 * tty->termios contains the new setting to be used.
371 static void ch341_set_termios(struct tty_struct *tty,
372 struct usb_serial_port *port, struct ktermios *old_termios)
374 struct ch341_private *priv = usb_get_serial_port_data(port);
380 /* redundant changes may cause the chip to lose bytes */
381 if (old_termios && !tty_termios_hw_change(tty->termios, old_termios))
384 dbg("ch341_set_termios()");
386 baud_rate = tty_get_baud_rate(tty);
388 ctrl = CH341_LCR_ENABLE_RX | CH341_LCR_ENABLE_TX | CH341_LCR_CS8;
391 priv->baud_rate = baud_rate;
393 r = ch341_set_baudrate_lcr(port->serial->dev, priv, ctrl);
394 if (r < 0 && old_termios) {
395 priv->baud_rate = tty_termios_baud_rate(old_termios);
396 tty_termios_copy_hw(tty->termios, old_termios);
400 spin_lock_irqsave(&priv->lock, flags);
401 if (C_BAUD(tty) == B0)
402 priv->line_control &= ~(CH341_BIT_DTR | CH341_BIT_RTS);
403 else if (old_termios && (old_termios->c_cflag & CBAUD) == B0)
404 priv->line_control |= (CH341_BIT_DTR | CH341_BIT_RTS);
405 spin_unlock_irqrestore(&priv->lock, flags);
408 * (cflag & CSIZE) : data bits [5, 8]
409 * (cflag & PARENB) : parity {NONE, EVEN, ODD}
410 * (cflag & CSTOPB) : stop bits [1, 2]
414 static void ch341_break_ctl(struct tty_struct *tty, int break_state)
416 const uint16_t ch341_break_reg =
417 ((uint16_t) CH341_REG_LCR << 8) | CH341_REG_BREAK;
418 struct usb_serial_port *port = tty->driver_data;
420 uint16_t reg_contents;
423 dbg("%s()", __func__);
425 break_reg = kmalloc(2, GFP_KERNEL);
427 dev_err(&port->dev, "%s - kmalloc failed\n", __func__);
431 r = ch341_control_in(port->serial->dev, CH341_REQ_READ_REG,
432 ch341_break_reg, 0, break_reg, 2);
434 dev_err(&port->dev, "%s - USB control read error (%d)\n",
438 dbg("%s - initial ch341 break register contents - reg1: %x, reg2: %x",
439 __func__, break_reg[0], break_reg[1]);
440 if (break_state != 0) {
441 dbg("%s - Enter break state requested", __func__);
442 break_reg[0] &= ~CH341_NBREAK_BITS;
443 break_reg[1] &= ~CH341_LCR_ENABLE_TX;
445 dbg("%s - Leave break state requested", __func__);
446 break_reg[0] |= CH341_NBREAK_BITS;
447 break_reg[1] |= CH341_LCR_ENABLE_TX;
449 dbg("%s - New ch341 break register contents - reg1: %x, reg2: %x",
450 __func__, break_reg[0], break_reg[1]);
451 reg_contents = get_unaligned_le16(break_reg);
452 r = ch341_control_out(port->serial->dev, CH341_REQ_WRITE_REG,
453 ch341_break_reg, reg_contents);
455 dev_err(&port->dev, "%s - USB control write error (%d)\n",
461 static int ch341_tiocmset(struct tty_struct *tty,
462 unsigned int set, unsigned int clear)
464 struct usb_serial_port *port = tty->driver_data;
465 struct ch341_private *priv = usb_get_serial_port_data(port);
469 spin_lock_irqsave(&priv->lock, flags);
471 priv->line_control |= CH341_BIT_RTS;
473 priv->line_control |= CH341_BIT_DTR;
474 if (clear & TIOCM_RTS)
475 priv->line_control &= ~CH341_BIT_RTS;
476 if (clear & TIOCM_DTR)
477 priv->line_control &= ~CH341_BIT_DTR;
478 control = priv->line_control;
479 spin_unlock_irqrestore(&priv->lock, flags);
481 return ch341_set_handshake(port->serial->dev, control);
484 static void ch341_read_int_callback(struct urb *urb)
486 struct usb_serial_port *port = (struct usb_serial_port *) urb->context;
487 unsigned char *data = urb->transfer_buffer;
488 unsigned int actual_length = urb->actual_length;
491 dbg("%s (%d)", __func__, port->number);
493 switch (urb->status) {
500 /* this urb is terminated, clean up */
501 dbg("%s - urb shutting down with status: %d", __func__,
505 dbg("%s - nonzero urb status received: %d", __func__,
510 usb_serial_debug_data(debug, &port->dev, __func__,
511 urb->actual_length, urb->transfer_buffer);
513 if (actual_length >= 4) {
514 struct ch341_private *priv = usb_get_serial_port_data(port);
516 u8 prev_line_status = priv->line_status;
518 spin_lock_irqsave(&priv->lock, flags);
519 priv->line_status = (~(data[2])) & CH341_BITS_MODEM_STAT;
520 if ((data[1] & CH341_MULT_STAT))
521 priv->multi_status_change = 1;
522 spin_unlock_irqrestore(&priv->lock, flags);
524 if ((priv->line_status ^ prev_line_status) & CH341_BIT_DCD) {
525 struct tty_struct *tty = tty_port_tty_get(&port->port);
527 usb_serial_handle_dcd_change(port, tty,
528 priv->line_status & CH341_BIT_DCD);
532 wake_up_interruptible(&port->delta_msr_wait);
536 status = usb_submit_urb(urb, GFP_ATOMIC);
538 dev_err(&urb->dev->dev,
539 "%s - usb_submit_urb failed with result %d\n",
543 static int wait_modem_info(struct usb_serial_port *port, unsigned int arg)
545 struct ch341_private *priv = usb_get_serial_port_data(port);
552 spin_lock_irqsave(&priv->lock, flags);
553 prevstatus = priv->line_status;
554 priv->multi_status_change = 0;
555 spin_unlock_irqrestore(&priv->lock, flags);
557 while (!multi_change) {
558 interruptible_sleep_on(&port->delta_msr_wait);
559 /* see if a signal did it */
560 if (signal_pending(current))
563 if (port->serial->disconnected)
566 spin_lock_irqsave(&priv->lock, flags);
567 status = priv->line_status;
568 multi_change = priv->multi_status_change;
569 spin_unlock_irqrestore(&priv->lock, flags);
571 changed = prevstatus ^ status;
573 if (((arg & TIOCM_RNG) && (changed & CH341_BIT_RI)) ||
574 ((arg & TIOCM_DSR) && (changed & CH341_BIT_DSR)) ||
575 ((arg & TIOCM_CD) && (changed & CH341_BIT_DCD)) ||
576 ((arg & TIOCM_CTS) && (changed & CH341_BIT_CTS))) {
585 static int ch341_ioctl(struct tty_struct *tty,
586 unsigned int cmd, unsigned long arg)
588 struct usb_serial_port *port = tty->driver_data;
589 dbg("%s (%d) cmd = 0x%04x", __func__, port->number, cmd);
593 dbg("%s (%d) TIOCMIWAIT", __func__, port->number);
594 return wait_modem_info(port, arg);
597 dbg("%s not supported = 0x%04x", __func__, cmd);
604 static int ch341_tiocmget(struct tty_struct *tty)
606 struct usb_serial_port *port = tty->driver_data;
607 struct ch341_private *priv = usb_get_serial_port_data(port);
613 dbg("%s (%d)", __func__, port->number);
615 spin_lock_irqsave(&priv->lock, flags);
616 mcr = priv->line_control;
617 status = priv->line_status;
618 spin_unlock_irqrestore(&priv->lock, flags);
620 result = ((mcr & CH341_BIT_DTR) ? TIOCM_DTR : 0)
621 | ((mcr & CH341_BIT_RTS) ? TIOCM_RTS : 0)
622 | ((status & CH341_BIT_CTS) ? TIOCM_CTS : 0)
623 | ((status & CH341_BIT_DSR) ? TIOCM_DSR : 0)
624 | ((status & CH341_BIT_RI) ? TIOCM_RI : 0)
625 | ((status & CH341_BIT_DCD) ? TIOCM_CD : 0);
627 dbg("%s - result = %x", __func__, result);
633 static int ch341_reset_resume(struct usb_interface *intf)
635 struct usb_device *dev = interface_to_usbdev(intf);
636 struct usb_serial *serial = usb_get_intfdata(intf);
637 struct usb_serial_port *port = serial->port[0];
638 struct ch341_private *priv = usb_get_serial_port_data(port);
641 /*reconfigure ch341 serial port after bus-reset*/
642 ch341_configure(dev, priv);
644 if (port->port.flags & ASYNC_INITIALIZED) {
645 ret = usb_submit_urb(port->interrupt_in_urb, GFP_NOIO);
647 dev_err(&port->dev, "failed to submit interrupt urb: %d\n",
652 ret = ch341_get_status(port->serial->dev, priv);
654 dev_err(&port->dev, "failed to read modem status: %d\n",
659 return usb_serial_generic_resume(serial);
662 static struct usb_driver ch341_driver = {
664 .probe = usb_serial_probe,
665 .disconnect = usb_serial_disconnect,
666 .suspend = usb_serial_suspend,
667 .resume = usb_serial_resume,
668 .reset_resume = ch341_reset_resume,
669 .id_table = id_table,
671 .supports_autosuspend = 1,
674 static struct usb_serial_driver ch341_device = {
676 .owner = THIS_MODULE,
677 .name = "ch341-uart",
679 .id_table = id_table,
680 .usb_driver = &ch341_driver,
683 .dtr_rts = ch341_dtr_rts,
684 .carrier_raised = ch341_carrier_raised,
685 .close = ch341_close,
686 .ioctl = ch341_ioctl,
687 .set_termios = ch341_set_termios,
688 .break_ctl = ch341_break_ctl,
689 .tiocmget = ch341_tiocmget,
690 .tiocmset = ch341_tiocmset,
691 .read_int_callback = ch341_read_int_callback,
692 .attach = ch341_attach,
695 static int __init ch341_init(void)
699 retval = usb_serial_register(&ch341_device);
702 retval = usb_register(&ch341_driver);
704 usb_serial_deregister(&ch341_device);
708 static void __exit ch341_exit(void)
710 usb_deregister(&ch341_driver);
711 usb_serial_deregister(&ch341_device);
714 module_init(ch341_init);
715 module_exit(ch341_exit);
716 MODULE_LICENSE("GPL");
718 module_param(debug, bool, S_IRUGO | S_IWUSR);
719 MODULE_PARM_DESC(debug, "Debug enabled or not");