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/tty.h>
20 #include <linux/module.h>
21 #include <linux/slab.h>
22 #include <linux/usb.h>
23 #include <linux/usb/serial.h>
24 #include <linux/serial.h>
25 #include <asm/unaligned.h>
27 #define DEFAULT_BAUD_RATE 9600
28 #define DEFAULT_TIMEOUT 1000
30 /* flags for IO-Bits */
31 #define CH341_BIT_RTS (1 << 6)
32 #define CH341_BIT_DTR (1 << 5)
34 /******************************/
35 /* interrupt pipe definitions */
36 /******************************/
37 /* always 4 interrupt bytes */
38 /* first irq byte normally 0x08 */
39 /* second irq byte base 0x7d + below */
40 /* third irq byte base 0x94 + below */
41 /* fourth irq byte normally 0xee */
43 /* second interrupt byte */
44 #define CH341_MULT_STAT 0x04 /* multiple status since last interrupt event */
46 /* status returned in third interrupt answer byte, inverted in data
48 #define CH341_BIT_CTS 0x01
49 #define CH341_BIT_DSR 0x02
50 #define CH341_BIT_RI 0x04
51 #define CH341_BIT_DCD 0x08
52 #define CH341_BITS_MODEM_STAT 0x0f /* all bits */
54 /*******************************/
55 /* baudrate calculation factor */
56 /*******************************/
57 #define CH341_BAUDBASE_FACTOR 1532620800
58 #define CH341_BAUDBASE_DIVMAX 3
60 /* Break support - the information used to implement this was gleaned from
61 * the Net/FreeBSD uchcom.c driver by Takanori Watanabe. Domo arigato.
64 #define CH341_REQ_WRITE_REG 0x9A
65 #define CH341_REQ_READ_REG 0x95
66 #define CH341_REG_BREAK1 0x05
67 #define CH341_REG_BREAK2 0x18
68 #define CH341_NBREAK_BITS_REG1 0x01
69 #define CH341_NBREAK_BITS_REG2 0x40
72 static const struct usb_device_id id_table[] = {
73 { USB_DEVICE(0x1a86, 0x5512) },
74 { USB_DEVICE(0x1a86, 0x5523) },
75 { USB_DEVICE(0x1a86, 0x7522) },
76 { USB_DEVICE(0x1a86, 0x7523) },
77 { USB_DEVICE(0x4348, 0x5523) },
78 { USB_DEVICE(0x9986, 0x7523) },
81 MODULE_DEVICE_TABLE(usb, id_table);
83 struct ch341_private {
84 spinlock_t lock; /* access lock */
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 */
90 static void ch341_set_termios(struct tty_struct *tty,
91 struct usb_serial_port *port,
92 struct ktermios *old_termios);
94 static int ch341_control_out(struct usb_device *dev, u8 request,
99 dev_dbg(&dev->dev, "ch341_control_out(%02x,%02x,%04x,%04x)\n",
100 USB_DIR_OUT|0x40, (int)request, (int)value, (int)index);
102 r = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), request,
103 USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT,
104 value, index, NULL, 0, DEFAULT_TIMEOUT);
106 dev_err(&dev->dev, "failed to send control message: %d\n", r);
111 static int ch341_control_in(struct usb_device *dev,
112 u8 request, u16 value, u16 index,
113 char *buf, unsigned bufsize)
117 dev_dbg(&dev->dev, "ch341_control_in(%02x,%02x,%04x,%04x,%p,%u)\n",
118 USB_DIR_IN|0x40, (int)request, (int)value, (int)index, buf,
121 r = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), request,
122 USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
123 value, index, buf, bufsize, DEFAULT_TIMEOUT);
124 if (r < (int)bufsize) {
127 "short control message received (%d < %u)\n",
132 dev_err(&dev->dev, "failed to receive control message: %d\n",
140 static int ch341_set_baudrate(struct usb_device *dev,
141 struct ch341_private *priv)
145 unsigned long factor;
148 if (!priv->baud_rate)
150 factor = (CH341_BAUDBASE_FACTOR / priv->baud_rate);
151 divisor = CH341_BAUDBASE_DIVMAX;
153 while ((factor > 0xfff0) && divisor) {
161 factor = 0x10000 - factor;
162 a = (factor & 0xff00) | divisor;
165 r = ch341_control_out(dev, 0x9a, 0x1312, a);
167 r = ch341_control_out(dev, 0x9a, 0x0f2c, b);
172 static int ch341_set_handshake(struct usb_device *dev, u8 control)
174 return ch341_control_out(dev, 0xa4, ~control, 0);
177 static int ch341_get_status(struct usb_device *dev, struct ch341_private *priv)
179 const unsigned int size = 2;
184 buffer = kmalloc(size, GFP_KERNEL);
188 r = ch341_control_in(dev, 0x95, 0x0706, 0, buffer, size);
192 spin_lock_irqsave(&priv->lock, flags);
193 priv->line_status = (~(*buffer)) & CH341_BITS_MODEM_STAT;
194 spin_unlock_irqrestore(&priv->lock, flags);
200 /* -------------------------------------------------------------------------- */
202 static int ch341_configure(struct usb_device *dev, struct ch341_private *priv)
204 const unsigned int size = 2;
208 buffer = kmalloc(size, GFP_KERNEL);
212 /* expect two bytes 0x27 0x00 */
213 r = ch341_control_in(dev, 0x5f, 0, 0, buffer, size);
217 r = ch341_control_out(dev, 0xa1, 0, 0);
221 r = ch341_set_baudrate(dev, priv);
225 /* expect two bytes 0x56 0x00 */
226 r = ch341_control_in(dev, 0x95, 0x2518, 0, buffer, size);
230 r = ch341_control_out(dev, 0x9a, 0x2518, 0x0050);
234 /* expect 0xff 0xee */
235 r = ch341_get_status(dev, priv);
239 r = ch341_control_out(dev, 0xa1, 0x501f, 0xd90a);
243 r = ch341_set_baudrate(dev, priv);
247 r = ch341_set_handshake(dev, priv->line_control);
251 /* expect 0x9f 0xee */
252 r = ch341_get_status(dev, priv);
258 static int ch341_port_probe(struct usb_serial_port *port)
260 struct ch341_private *priv;
263 priv = kzalloc(sizeof(struct ch341_private), GFP_KERNEL);
267 spin_lock_init(&priv->lock);
268 priv->baud_rate = DEFAULT_BAUD_RATE;
270 r = ch341_configure(port->serial->dev, priv);
274 usb_set_serial_port_data(port, priv);
281 static int ch341_port_remove(struct usb_serial_port *port)
283 struct ch341_private *priv;
285 priv = usb_get_serial_port_data(port);
291 static int ch341_carrier_raised(struct usb_serial_port *port)
293 struct ch341_private *priv = usb_get_serial_port_data(port);
294 if (priv->line_status & CH341_BIT_DCD)
299 static void ch341_dtr_rts(struct usb_serial_port *port, int on)
301 struct ch341_private *priv = usb_get_serial_port_data(port);
304 /* drop DTR and RTS */
305 spin_lock_irqsave(&priv->lock, flags);
307 priv->line_control |= CH341_BIT_RTS | CH341_BIT_DTR;
309 priv->line_control &= ~(CH341_BIT_RTS | CH341_BIT_DTR);
310 spin_unlock_irqrestore(&priv->lock, flags);
311 ch341_set_handshake(port->serial->dev, priv->line_control);
314 static void ch341_close(struct usb_serial_port *port)
316 usb_serial_generic_close(port);
317 usb_kill_urb(port->interrupt_in_urb);
321 /* open this device, set default parameters */
322 static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port)
324 struct usb_serial *serial = port->serial;
325 struct ch341_private *priv = usb_get_serial_port_data(port);
328 r = ch341_configure(serial->dev, priv);
333 ch341_set_termios(tty, port, NULL);
335 dev_dbg(&port->dev, "%s - submitting interrupt urb\n", __func__);
336 r = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
338 dev_err(&port->dev, "%s - failed to submit interrupt urb: %d\n",
343 r = usb_serial_generic_open(tty, port);
345 goto err_kill_interrupt_urb;
349 err_kill_interrupt_urb:
350 usb_kill_urb(port->interrupt_in_urb);
355 /* Old_termios contains the original termios settings and
356 * tty->termios contains the new setting to be used.
358 static void ch341_set_termios(struct tty_struct *tty,
359 struct usb_serial_port *port, struct ktermios *old_termios)
361 struct ch341_private *priv = usb_get_serial_port_data(port);
365 baud_rate = tty_get_baud_rate(tty);
368 priv->baud_rate = baud_rate;
369 ch341_set_baudrate(port->serial->dev, priv);
373 * (cflag & CSIZE) : data bits [5, 8]
374 * (cflag & PARENB) : parity {NONE, EVEN, ODD}
375 * (cflag & CSTOPB) : stop bits [1, 2]
378 spin_lock_irqsave(&priv->lock, flags);
379 if (C_BAUD(tty) == B0)
380 priv->line_control &= ~(CH341_BIT_DTR | CH341_BIT_RTS);
381 else if (old_termios && (old_termios->c_cflag & CBAUD) == B0)
382 priv->line_control |= (CH341_BIT_DTR | CH341_BIT_RTS);
383 spin_unlock_irqrestore(&priv->lock, flags);
385 ch341_set_handshake(port->serial->dev, priv->line_control);
388 static void ch341_break_ctl(struct tty_struct *tty, int break_state)
390 const uint16_t ch341_break_reg =
391 CH341_REG_BREAK1 | ((uint16_t) CH341_REG_BREAK2 << 8);
392 struct usb_serial_port *port = tty->driver_data;
394 uint16_t reg_contents;
397 break_reg = kmalloc(2, GFP_KERNEL);
401 r = ch341_control_in(port->serial->dev, CH341_REQ_READ_REG,
402 ch341_break_reg, 0, break_reg, 2);
404 dev_err(&port->dev, "%s - USB control read error (%d)\n",
408 dev_dbg(&port->dev, "%s - initial ch341 break register contents - reg1: %x, reg2: %x\n",
409 __func__, break_reg[0], break_reg[1]);
410 if (break_state != 0) {
411 dev_dbg(&port->dev, "%s - Enter break state requested\n", __func__);
412 break_reg[0] &= ~CH341_NBREAK_BITS_REG1;
413 break_reg[1] &= ~CH341_NBREAK_BITS_REG2;
415 dev_dbg(&port->dev, "%s - Leave break state requested\n", __func__);
416 break_reg[0] |= CH341_NBREAK_BITS_REG1;
417 break_reg[1] |= CH341_NBREAK_BITS_REG2;
419 dev_dbg(&port->dev, "%s - New ch341 break register contents - reg1: %x, reg2: %x\n",
420 __func__, break_reg[0], break_reg[1]);
421 reg_contents = get_unaligned_le16(break_reg);
422 r = ch341_control_out(port->serial->dev, CH341_REQ_WRITE_REG,
423 ch341_break_reg, reg_contents);
425 dev_err(&port->dev, "%s - USB control write error (%d)\n",
431 static int ch341_tiocmset(struct tty_struct *tty,
432 unsigned int set, unsigned int clear)
434 struct usb_serial_port *port = tty->driver_data;
435 struct ch341_private *priv = usb_get_serial_port_data(port);
439 spin_lock_irqsave(&priv->lock, flags);
441 priv->line_control |= CH341_BIT_RTS;
443 priv->line_control |= CH341_BIT_DTR;
444 if (clear & TIOCM_RTS)
445 priv->line_control &= ~CH341_BIT_RTS;
446 if (clear & TIOCM_DTR)
447 priv->line_control &= ~CH341_BIT_DTR;
448 control = priv->line_control;
449 spin_unlock_irqrestore(&priv->lock, flags);
451 return ch341_set_handshake(port->serial->dev, control);
454 static void ch341_update_line_status(struct usb_serial_port *port,
455 unsigned char *data, size_t len)
457 struct ch341_private *priv = usb_get_serial_port_data(port);
458 struct tty_struct *tty;
466 status = ~data[2] & CH341_BITS_MODEM_STAT;
468 spin_lock_irqsave(&priv->lock, flags);
469 delta = status ^ priv->line_status;
470 priv->line_status = status;
471 spin_unlock_irqrestore(&priv->lock, flags);
473 if (data[1] & CH341_MULT_STAT)
474 dev_dbg(&port->dev, "%s - multiple status change\n", __func__);
479 if (delta & CH341_BIT_CTS)
481 if (delta & CH341_BIT_DSR)
483 if (delta & CH341_BIT_RI)
485 if (delta & CH341_BIT_DCD) {
487 tty = tty_port_tty_get(&port->port);
489 usb_serial_handle_dcd_change(port, tty,
490 status & CH341_BIT_DCD);
495 wake_up_interruptible(&port->port.delta_msr_wait);
498 static void ch341_read_int_callback(struct urb *urb)
500 struct usb_serial_port *port = urb->context;
501 unsigned char *data = urb->transfer_buffer;
502 unsigned int len = urb->actual_length;
505 switch (urb->status) {
512 /* this urb is terminated, clean up */
513 dev_dbg(&urb->dev->dev, "%s - urb shutting down: %d\n",
514 __func__, urb->status);
517 dev_dbg(&urb->dev->dev, "%s - nonzero urb status: %d\n",
518 __func__, urb->status);
522 usb_serial_debug_data(&port->dev, __func__, len, data);
523 ch341_update_line_status(port, data, len);
525 status = usb_submit_urb(urb, GFP_ATOMIC);
527 dev_err(&urb->dev->dev, "%s - usb_submit_urb failed: %d\n",
532 static int ch341_tiocmget(struct tty_struct *tty)
534 struct usb_serial_port *port = tty->driver_data;
535 struct ch341_private *priv = usb_get_serial_port_data(port);
541 spin_lock_irqsave(&priv->lock, flags);
542 mcr = priv->line_control;
543 status = priv->line_status;
544 spin_unlock_irqrestore(&priv->lock, flags);
546 result = ((mcr & CH341_BIT_DTR) ? TIOCM_DTR : 0)
547 | ((mcr & CH341_BIT_RTS) ? TIOCM_RTS : 0)
548 | ((status & CH341_BIT_CTS) ? TIOCM_CTS : 0)
549 | ((status & CH341_BIT_DSR) ? TIOCM_DSR : 0)
550 | ((status & CH341_BIT_RI) ? TIOCM_RI : 0)
551 | ((status & CH341_BIT_DCD) ? TIOCM_CD : 0);
553 dev_dbg(&port->dev, "%s - result = %x\n", __func__, result);
558 static int ch341_reset_resume(struct usb_serial *serial)
560 struct usb_serial_port *port = serial->port[0];
561 struct ch341_private *priv;
564 priv = usb_get_serial_port_data(port);
568 /* reconfigure ch341 serial port after bus-reset */
569 ch341_configure(serial->dev, priv);
571 if (test_bit(ASYNCB_INITIALIZED, &port->port.flags)) {
572 ret = usb_submit_urb(port->interrupt_in_urb, GFP_NOIO);
574 dev_err(&port->dev, "failed to submit interrupt urb: %d\n",
580 return usb_serial_generic_resume(serial);
583 static struct usb_serial_driver ch341_device = {
585 .owner = THIS_MODULE,
586 .name = "ch341-uart",
588 .id_table = id_table,
591 .dtr_rts = ch341_dtr_rts,
592 .carrier_raised = ch341_carrier_raised,
593 .close = ch341_close,
594 .set_termios = ch341_set_termios,
595 .break_ctl = ch341_break_ctl,
596 .tiocmget = ch341_tiocmget,
597 .tiocmset = ch341_tiocmset,
598 .tiocmiwait = usb_serial_generic_tiocmiwait,
599 .read_int_callback = ch341_read_int_callback,
600 .port_probe = ch341_port_probe,
601 .port_remove = ch341_port_remove,
602 .reset_resume = ch341_reset_resume,
605 static struct usb_serial_driver * const serial_drivers[] = {
609 module_usb_serial_driver(serial_drivers, id_table);
611 MODULE_LICENSE("GPL");