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_READ_VERSION 0x5F
65 #define CH341_REQ_WRITE_REG 0x9A
66 #define CH341_REQ_READ_REG 0x95
67 #define CH341_REQ_SERIAL_INIT 0xA1
68 #define CH341_REQ_MODEM_CTRL 0xA4
70 #define CH341_REG_BREAK 0x05
71 #define CH341_REG_LCR 0x18
72 #define CH341_NBREAK_BITS 0x01
74 #define CH341_LCR_ENABLE_RX 0x80
75 #define CH341_LCR_ENABLE_TX 0x40
76 #define CH341_LCR_MARK_SPACE 0x20
77 #define CH341_LCR_PAR_EVEN 0x10
78 #define CH341_LCR_ENABLE_PAR 0x08
79 #define CH341_LCR_STOP_BITS_2 0x04
80 #define CH341_LCR_CS8 0x03
81 #define CH341_LCR_CS7 0x02
82 #define CH341_LCR_CS6 0x01
83 #define CH341_LCR_CS5 0x00
85 static const struct usb_device_id id_table[] = {
86 { USB_DEVICE(0x1a86, 0x5512) },
87 { USB_DEVICE(0x1a86, 0x5523) },
88 { USB_DEVICE(0x1a86, 0x7522) },
89 { USB_DEVICE(0x1a86, 0x7523) },
90 { USB_DEVICE(0x4348, 0x5523) },
91 { USB_DEVICE(0x9986, 0x7523) },
94 MODULE_DEVICE_TABLE(usb, id_table);
96 struct ch341_private {
97 spinlock_t lock; /* access lock */
98 unsigned baud_rate; /* set baud rate */
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)
113 dev_dbg(&dev->dev, "%s - (%02x,%04x,%04x)\n", __func__,
114 request, value, index);
116 r = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), request,
117 USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT,
118 value, index, NULL, 0, DEFAULT_TIMEOUT);
120 dev_err(&dev->dev, "failed to send control message: %d\n", r);
125 static int ch341_control_in(struct usb_device *dev,
126 u8 request, u16 value, u16 index,
127 char *buf, unsigned bufsize)
131 dev_dbg(&dev->dev, "%s - (%02x,%04x,%04x,%u)\n", __func__,
132 request, value, index, bufsize);
134 r = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), request,
135 USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
136 value, index, buf, bufsize, DEFAULT_TIMEOUT);
137 if (r < (int)bufsize) {
140 "short control message received (%d < %u)\n",
145 dev_err(&dev->dev, "failed to receive control message: %d\n",
153 static int ch341_set_baudrate_lcr(struct usb_device *dev,
154 struct ch341_private *priv, u8 lcr)
158 unsigned long factor;
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 return ch341_control_out(dev, CH341_REQ_MODEM_CTRL, ~control, 0);
199 static int ch341_get_status(struct usb_device *dev, struct ch341_private *priv)
201 const unsigned int size = 2;
206 buffer = kmalloc(size, GFP_KERNEL);
210 r = ch341_control_in(dev, CH341_REQ_READ_REG, 0x0706, 0, buffer, size);
214 spin_lock_irqsave(&priv->lock, flags);
215 priv->msr = (~(*buffer)) & CH341_BITS_MODEM_STAT;
216 spin_unlock_irqrestore(&priv->lock, flags);
222 /* -------------------------------------------------------------------------- */
224 static int ch341_configure(struct usb_device *dev, struct ch341_private *priv)
226 const unsigned int size = 2;
230 buffer = kmalloc(size, GFP_KERNEL);
234 /* expect two bytes 0x27 0x00 */
235 r = ch341_control_in(dev, CH341_REQ_READ_VERSION, 0, 0, buffer, size);
238 dev_dbg(&dev->dev, "Chip version: 0x%02x\n", buffer[0]);
240 r = ch341_control_out(dev, CH341_REQ_SERIAL_INIT, 0, 0);
244 r = ch341_set_baudrate_lcr(dev, priv, priv->lcr);
248 r = ch341_set_handshake(dev, priv->mcr);
254 static int ch341_port_probe(struct usb_serial_port *port)
256 struct ch341_private *priv;
259 priv = kzalloc(sizeof(struct ch341_private), GFP_KERNEL);
263 spin_lock_init(&priv->lock);
264 priv->baud_rate = DEFAULT_BAUD_RATE;
266 * Some CH340 devices appear unable to change the initial LCR
267 * settings, so set a sane 8N1 default.
269 priv->lcr = CH341_LCR_ENABLE_RX | CH341_LCR_ENABLE_TX | CH341_LCR_CS8;
271 r = ch341_configure(port->serial->dev, priv);
275 usb_set_serial_port_data(port, priv);
282 static int ch341_port_remove(struct usb_serial_port *port)
284 struct ch341_private *priv;
286 priv = usb_get_serial_port_data(port);
292 static int ch341_carrier_raised(struct usb_serial_port *port)
294 struct ch341_private *priv = usb_get_serial_port_data(port);
295 if (priv->msr & CH341_BIT_DCD)
300 static void ch341_dtr_rts(struct usb_serial_port *port, int on)
302 struct ch341_private *priv = usb_get_serial_port_data(port);
305 /* drop DTR and RTS */
306 spin_lock_irqsave(&priv->lock, flags);
308 priv->mcr |= CH341_BIT_RTS | CH341_BIT_DTR;
310 priv->mcr &= ~(CH341_BIT_RTS | CH341_BIT_DTR);
311 spin_unlock_irqrestore(&priv->lock, flags);
312 ch341_set_handshake(port->serial->dev, priv->mcr);
315 static void ch341_close(struct usb_serial_port *port)
317 usb_serial_generic_close(port);
318 usb_kill_urb(port->interrupt_in_urb);
322 /* open this device, set default parameters */
323 static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port)
325 struct ch341_private *priv = usb_get_serial_port_data(port);
329 ch341_set_termios(tty, port, NULL);
331 dev_dbg(&port->dev, "%s - submitting interrupt urb\n", __func__);
332 r = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
334 dev_err(&port->dev, "%s - failed to submit interrupt urb: %d\n",
339 r = ch341_get_status(port->serial->dev, priv);
341 dev_err(&port->dev, "failed to read modem status: %d\n", r);
342 goto err_kill_interrupt_urb;
345 r = usb_serial_generic_open(tty, port);
347 goto err_kill_interrupt_urb;
351 err_kill_interrupt_urb:
352 usb_kill_urb(port->interrupt_in_urb);
357 /* Old_termios contains the original termios settings and
358 * tty->termios contains the new setting to be used.
360 static void ch341_set_termios(struct tty_struct *tty,
361 struct usb_serial_port *port, struct ktermios *old_termios)
363 struct ch341_private *priv = usb_get_serial_port_data(port);
369 /* redundant changes may cause the chip to lose bytes */
370 if (old_termios && !tty_termios_hw_change(&tty->termios, old_termios))
373 baud_rate = tty_get_baud_rate(tty);
375 lcr = CH341_LCR_ENABLE_RX | CH341_LCR_ENABLE_TX;
377 switch (C_CSIZE(tty)) {
379 lcr |= CH341_LCR_CS5;
382 lcr |= CH341_LCR_CS6;
385 lcr |= CH341_LCR_CS7;
388 lcr |= CH341_LCR_CS8;
393 lcr |= CH341_LCR_ENABLE_PAR;
394 if (C_PARODD(tty) == 0)
395 lcr |= CH341_LCR_PAR_EVEN;
397 lcr |= CH341_LCR_MARK_SPACE;
401 lcr |= CH341_LCR_STOP_BITS_2;
404 priv->baud_rate = baud_rate;
406 r = ch341_set_baudrate_lcr(port->serial->dev, priv, lcr);
407 if (r < 0 && old_termios) {
408 priv->baud_rate = tty_termios_baud_rate(old_termios);
409 tty_termios_copy_hw(&tty->termios, old_termios);
415 spin_lock_irqsave(&priv->lock, flags);
416 if (C_BAUD(tty) == B0)
417 priv->mcr &= ~(CH341_BIT_DTR | CH341_BIT_RTS);
418 else if (old_termios && (old_termios->c_cflag & CBAUD) == B0)
419 priv->mcr |= (CH341_BIT_DTR | CH341_BIT_RTS);
420 spin_unlock_irqrestore(&priv->lock, flags);
422 ch341_set_handshake(port->serial->dev, priv->mcr);
425 static void ch341_break_ctl(struct tty_struct *tty, int break_state)
427 const uint16_t ch341_break_reg =
428 ((uint16_t) CH341_REG_LCR << 8) | CH341_REG_BREAK;
429 struct usb_serial_port *port = tty->driver_data;
431 uint16_t reg_contents;
434 break_reg = kmalloc(2, GFP_KERNEL);
438 r = ch341_control_in(port->serial->dev, CH341_REQ_READ_REG,
439 ch341_break_reg, 0, break_reg, 2);
441 dev_err(&port->dev, "%s - USB control read error (%d)\n",
445 dev_dbg(&port->dev, "%s - initial ch341 break register contents - reg1: %x, reg2: %x\n",
446 __func__, break_reg[0], break_reg[1]);
447 if (break_state != 0) {
448 dev_dbg(&port->dev, "%s - Enter break state requested\n", __func__);
449 break_reg[0] &= ~CH341_NBREAK_BITS;
450 break_reg[1] &= ~CH341_LCR_ENABLE_TX;
452 dev_dbg(&port->dev, "%s - Leave break state requested\n", __func__);
453 break_reg[0] |= CH341_NBREAK_BITS;
454 break_reg[1] |= CH341_LCR_ENABLE_TX;
456 dev_dbg(&port->dev, "%s - New ch341 break register contents - reg1: %x, reg2: %x\n",
457 __func__, break_reg[0], break_reg[1]);
458 reg_contents = get_unaligned_le16(break_reg);
459 r = ch341_control_out(port->serial->dev, CH341_REQ_WRITE_REG,
460 ch341_break_reg, reg_contents);
462 dev_err(&port->dev, "%s - USB control write error (%d)\n",
468 static int ch341_tiocmset(struct tty_struct *tty,
469 unsigned int set, unsigned int clear)
471 struct usb_serial_port *port = tty->driver_data;
472 struct ch341_private *priv = usb_get_serial_port_data(port);
476 spin_lock_irqsave(&priv->lock, flags);
478 priv->mcr |= CH341_BIT_RTS;
480 priv->mcr |= CH341_BIT_DTR;
481 if (clear & TIOCM_RTS)
482 priv->mcr &= ~CH341_BIT_RTS;
483 if (clear & TIOCM_DTR)
484 priv->mcr &= ~CH341_BIT_DTR;
486 spin_unlock_irqrestore(&priv->lock, flags);
488 return ch341_set_handshake(port->serial->dev, control);
491 static void ch341_update_status(struct usb_serial_port *port,
492 unsigned char *data, size_t len)
494 struct ch341_private *priv = usb_get_serial_port_data(port);
495 struct tty_struct *tty;
503 status = ~data[2] & CH341_BITS_MODEM_STAT;
505 spin_lock_irqsave(&priv->lock, flags);
506 delta = status ^ priv->msr;
508 spin_unlock_irqrestore(&priv->lock, flags);
510 if (data[1] & CH341_MULT_STAT)
511 dev_dbg(&port->dev, "%s - multiple status change\n", __func__);
516 if (delta & CH341_BIT_CTS)
518 if (delta & CH341_BIT_DSR)
520 if (delta & CH341_BIT_RI)
522 if (delta & CH341_BIT_DCD) {
524 tty = tty_port_tty_get(&port->port);
526 usb_serial_handle_dcd_change(port, tty,
527 status & CH341_BIT_DCD);
532 wake_up_interruptible(&port->port.delta_msr_wait);
535 static void ch341_read_int_callback(struct urb *urb)
537 struct usb_serial_port *port = urb->context;
538 unsigned char *data = urb->transfer_buffer;
539 unsigned int len = urb->actual_length;
542 switch (urb->status) {
549 /* this urb is terminated, clean up */
550 dev_dbg(&urb->dev->dev, "%s - urb shutting down: %d\n",
551 __func__, urb->status);
554 dev_dbg(&urb->dev->dev, "%s - nonzero urb status: %d\n",
555 __func__, urb->status);
559 usb_serial_debug_data(&port->dev, __func__, len, data);
560 ch341_update_status(port, data, len);
562 status = usb_submit_urb(urb, GFP_ATOMIC);
564 dev_err(&urb->dev->dev, "%s - usb_submit_urb failed: %d\n",
569 static int ch341_tiocmget(struct tty_struct *tty)
571 struct usb_serial_port *port = tty->driver_data;
572 struct ch341_private *priv = usb_get_serial_port_data(port);
578 spin_lock_irqsave(&priv->lock, flags);
581 spin_unlock_irqrestore(&priv->lock, flags);
583 result = ((mcr & CH341_BIT_DTR) ? TIOCM_DTR : 0)
584 | ((mcr & CH341_BIT_RTS) ? TIOCM_RTS : 0)
585 | ((status & CH341_BIT_CTS) ? TIOCM_CTS : 0)
586 | ((status & CH341_BIT_DSR) ? TIOCM_DSR : 0)
587 | ((status & CH341_BIT_RI) ? TIOCM_RI : 0)
588 | ((status & CH341_BIT_DCD) ? TIOCM_CD : 0);
590 dev_dbg(&port->dev, "%s - result = %x\n", __func__, result);
595 static int ch341_reset_resume(struct usb_serial *serial)
597 struct usb_serial_port *port = serial->port[0];
598 struct ch341_private *priv;
601 priv = usb_get_serial_port_data(port);
605 /* reconfigure ch341 serial port after bus-reset */
606 ch341_configure(serial->dev, priv);
608 if (tty_port_initialized(&port->port)) {
609 ret = usb_submit_urb(port->interrupt_in_urb, GFP_NOIO);
611 dev_err(&port->dev, "failed to submit interrupt urb: %d\n",
616 ret = ch341_get_status(port->serial->dev, priv);
618 dev_err(&port->dev, "failed to read modem status: %d\n",
623 return usb_serial_generic_resume(serial);
626 static struct usb_serial_driver ch341_device = {
628 .owner = THIS_MODULE,
629 .name = "ch341-uart",
631 .id_table = id_table,
634 .dtr_rts = ch341_dtr_rts,
635 .carrier_raised = ch341_carrier_raised,
636 .close = ch341_close,
637 .set_termios = ch341_set_termios,
638 .break_ctl = ch341_break_ctl,
639 .tiocmget = ch341_tiocmget,
640 .tiocmset = ch341_tiocmset,
641 .tiocmiwait = usb_serial_generic_tiocmiwait,
642 .read_int_callback = ch341_read_int_callback,
643 .port_probe = ch341_port_probe,
644 .port_remove = ch341_port_remove,
645 .reset_resume = ch341_reset_resume,
648 static struct usb_serial_driver * const serial_drivers[] = {
652 module_usb_serial_driver(serial_drivers, id_table);
654 MODULE_LICENSE("GPL");