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
73 static const struct usb_device_id id_table[] = {
74 { USB_DEVICE(0x4348, 0x5523) },
75 { USB_DEVICE(0x1a86, 0x7523) },
76 { USB_DEVICE(0x1a86, 0x5523) },
79 MODULE_DEVICE_TABLE(usb, id_table);
81 struct ch341_private {
82 spinlock_t lock; /* access lock */
83 wait_queue_head_t delta_msr_wait; /* wait queue for modem status */
84 unsigned baud_rate; /* set baud rate */
85 u8 line_control; /* set line control value RTS/DTR */
86 u8 line_status; /* active status of modem control inputs */
87 u8 multi_status_change; /* status changed multiple since last call */
90 static int ch341_control_out(struct usb_device *dev, u8 request,
95 dev_dbg(&dev->dev, "ch341_control_out(%02x,%02x,%04x,%04x)\n",
96 USB_DIR_OUT|0x40, (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)
111 dev_dbg(&dev->dev, "ch341_control_in(%02x,%02x,%04x,%04x,%p,%u)\n",
112 USB_DIR_IN|0x40, (int)request, (int)value, (int)index, buf,
115 r = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), request,
116 USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
117 value, index, buf, bufsize, DEFAULT_TIMEOUT);
121 static int ch341_set_baudrate(struct usb_device *dev,
122 struct ch341_private *priv)
126 unsigned long factor;
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 return ch341_control_out(dev, 0xa4, ~control, 0);
158 static int ch341_get_status(struct usb_device *dev, struct ch341_private *priv)
162 const unsigned size = 8;
165 buffer = kmalloc(size, GFP_KERNEL);
169 r = ch341_control_in(dev, 0x95, 0x0706, 0, buffer, size);
173 /* setup the private status if available */
176 spin_lock_irqsave(&priv->lock, flags);
177 priv->line_status = (~(*buffer)) & CH341_BITS_MODEM_STAT;
178 priv->multi_status_change = 0;
179 spin_unlock_irqrestore(&priv->lock, flags);
187 /* -------------------------------------------------------------------------- */
189 static int ch341_configure(struct usb_device *dev, struct ch341_private *priv)
193 const unsigned size = 8;
195 buffer = kmalloc(size, GFP_KERNEL);
199 /* expect two bytes 0x27 0x00 */
200 r = ch341_control_in(dev, 0x5f, 0, 0, buffer, size);
204 r = ch341_control_out(dev, 0xa1, 0, 0);
208 r = ch341_set_baudrate(dev, priv);
212 /* expect two bytes 0x56 0x00 */
213 r = ch341_control_in(dev, 0x95, 0x2518, 0, buffer, size);
217 r = ch341_control_out(dev, 0x9a, 0x2518, 0x0050);
221 /* expect 0xff 0xee */
222 r = ch341_get_status(dev, priv);
226 r = ch341_control_out(dev, 0xa1, 0x501f, 0xd90a);
230 r = ch341_set_baudrate(dev, priv);
234 r = ch341_set_handshake(dev, priv->line_control);
238 /* expect 0x9f 0xee */
239 r = ch341_get_status(dev, priv);
245 static int ch341_port_probe(struct usb_serial_port *port)
247 struct ch341_private *priv;
250 priv = kzalloc(sizeof(struct ch341_private), GFP_KERNEL);
254 spin_lock_init(&priv->lock);
255 init_waitqueue_head(&priv->delta_msr_wait);
256 priv->baud_rate = DEFAULT_BAUD_RATE;
257 priv->line_control = CH341_BIT_RTS | CH341_BIT_DTR;
259 r = ch341_configure(port->serial->dev, priv);
263 usb_set_serial_port_data(port, priv);
270 static int ch341_port_remove(struct usb_serial_port *port)
272 struct ch341_private *priv;
274 priv = usb_get_serial_port_data(port);
280 static int ch341_carrier_raised(struct usb_serial_port *port)
282 struct ch341_private *priv = usb_get_serial_port_data(port);
283 if (priv->line_status & CH341_BIT_DCD)
288 static void ch341_dtr_rts(struct usb_serial_port *port, int on)
290 struct ch341_private *priv = usb_get_serial_port_data(port);
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 usb_serial_generic_close(port);
307 usb_kill_urb(port->interrupt_in_urb);
311 /* open this device, set default parameters */
312 static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port)
314 struct usb_serial *serial = port->serial;
315 struct ch341_private *priv = usb_get_serial_port_data(port);
318 priv->baud_rate = DEFAULT_BAUD_RATE;
320 r = ch341_configure(serial->dev, priv);
324 r = ch341_set_handshake(serial->dev, priv->line_control);
328 r = ch341_set_baudrate(serial->dev, priv);
332 dev_dbg(&port->dev, "%s - submitting interrupt urb", __func__);
333 r = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
335 dev_err(&port->dev, "%s - failed submitting interrupt urb,"
336 " error %d\n", __func__, r);
341 r = usb_serial_generic_open(tty, port);
346 /* Old_termios contains the original termios settings and
347 * tty->termios contains the new setting to be used.
349 static void ch341_set_termios(struct tty_struct *tty,
350 struct usb_serial_port *port, struct ktermios *old_termios)
352 struct ch341_private *priv = usb_get_serial_port_data(port);
356 baud_rate = tty_get_baud_rate(tty);
358 priv->baud_rate = baud_rate;
361 spin_lock_irqsave(&priv->lock, flags);
362 priv->line_control |= (CH341_BIT_DTR | CH341_BIT_RTS);
363 spin_unlock_irqrestore(&priv->lock, flags);
364 ch341_set_baudrate(port->serial->dev, priv);
366 spin_lock_irqsave(&priv->lock, flags);
367 priv->line_control &= ~(CH341_BIT_DTR | CH341_BIT_RTS);
368 spin_unlock_irqrestore(&priv->lock, flags);
371 ch341_set_handshake(port->serial->dev, priv->line_control);
374 * (cflag & CSIZE) : data bits [5, 8]
375 * (cflag & PARENB) : parity {NONE, EVEN, ODD}
376 * (cflag & CSTOPB) : stop bits [1, 2]
380 static void ch341_break_ctl(struct tty_struct *tty, int break_state)
382 const uint16_t ch341_break_reg =
383 CH341_REG_BREAK1 | ((uint16_t) CH341_REG_BREAK2 << 8);
384 struct usb_serial_port *port = tty->driver_data;
386 uint16_t reg_contents;
389 break_reg = kmalloc(2, GFP_KERNEL);
391 dev_err(&port->dev, "%s - kmalloc failed\n", __func__);
395 r = ch341_control_in(port->serial->dev, CH341_REQ_READ_REG,
396 ch341_break_reg, 0, break_reg, 2);
398 dev_err(&port->dev, "%s - USB control read error (%d)\n",
402 dev_dbg(&port->dev, "%s - initial ch341 break register contents - reg1: %x, reg2: %x\n",
403 __func__, break_reg[0], break_reg[1]);
404 if (break_state != 0) {
405 dev_dbg(&port->dev, "%s - Enter break state requested\n", __func__);
406 break_reg[0] &= ~CH341_NBREAK_BITS_REG1;
407 break_reg[1] &= ~CH341_NBREAK_BITS_REG2;
409 dev_dbg(&port->dev, "%s - Leave break state requested\n", __func__);
410 break_reg[0] |= CH341_NBREAK_BITS_REG1;
411 break_reg[1] |= CH341_NBREAK_BITS_REG2;
413 dev_dbg(&port->dev, "%s - New ch341 break register contents - reg1: %x, reg2: %x\n",
414 __func__, break_reg[0], break_reg[1]);
415 reg_contents = get_unaligned_le16(break_reg);
416 r = ch341_control_out(port->serial->dev, CH341_REQ_WRITE_REG,
417 ch341_break_reg, reg_contents);
419 dev_err(&port->dev, "%s - USB control write error (%d)\n",
425 static int ch341_tiocmset(struct tty_struct *tty,
426 unsigned int set, unsigned int clear)
428 struct usb_serial_port *port = tty->driver_data;
429 struct ch341_private *priv = usb_get_serial_port_data(port);
433 spin_lock_irqsave(&priv->lock, flags);
435 priv->line_control |= CH341_BIT_RTS;
437 priv->line_control |= CH341_BIT_DTR;
438 if (clear & TIOCM_RTS)
439 priv->line_control &= ~CH341_BIT_RTS;
440 if (clear & TIOCM_DTR)
441 priv->line_control &= ~CH341_BIT_DTR;
442 control = priv->line_control;
443 spin_unlock_irqrestore(&priv->lock, flags);
445 return ch341_set_handshake(port->serial->dev, control);
448 static void ch341_read_int_callback(struct urb *urb)
450 struct usb_serial_port *port = (struct usb_serial_port *) urb->context;
451 unsigned char *data = urb->transfer_buffer;
452 unsigned int actual_length = urb->actual_length;
455 switch (urb->status) {
462 /* this urb is terminated, clean up */
463 dev_dbg(&urb->dev->dev, "%s - urb shutting down with status: %d\n",
464 __func__, urb->status);
467 dev_dbg(&urb->dev->dev, "%s - nonzero urb status received: %d\n",
468 __func__, urb->status);
472 usb_serial_debug_data(&port->dev, __func__,
473 urb->actual_length, urb->transfer_buffer);
475 if (actual_length >= 4) {
476 struct ch341_private *priv = usb_get_serial_port_data(port);
478 u8 prev_line_status = priv->line_status;
480 spin_lock_irqsave(&priv->lock, flags);
481 priv->line_status = (~(data[2])) & CH341_BITS_MODEM_STAT;
482 if ((data[1] & CH341_MULT_STAT))
483 priv->multi_status_change = 1;
484 spin_unlock_irqrestore(&priv->lock, flags);
486 if ((priv->line_status ^ prev_line_status) & CH341_BIT_DCD) {
487 struct tty_struct *tty = tty_port_tty_get(&port->port);
489 usb_serial_handle_dcd_change(port, tty,
490 priv->line_status & CH341_BIT_DCD);
494 wake_up_interruptible(&priv->delta_msr_wait);
498 status = usb_submit_urb(urb, GFP_ATOMIC);
500 dev_err(&urb->dev->dev,
501 "%s - usb_submit_urb failed with result %d\n",
505 static int wait_modem_info(struct usb_serial_port *port, unsigned int arg)
507 struct ch341_private *priv = usb_get_serial_port_data(port);
514 spin_lock_irqsave(&priv->lock, flags);
515 prevstatus = priv->line_status;
516 priv->multi_status_change = 0;
517 spin_unlock_irqrestore(&priv->lock, flags);
519 while (!multi_change) {
520 interruptible_sleep_on(&priv->delta_msr_wait);
521 /* see if a signal did it */
522 if (signal_pending(current))
525 spin_lock_irqsave(&priv->lock, flags);
526 status = priv->line_status;
527 multi_change = priv->multi_status_change;
528 spin_unlock_irqrestore(&priv->lock, flags);
530 changed = prevstatus ^ status;
532 if (((arg & TIOCM_RNG) && (changed & CH341_BIT_RI)) ||
533 ((arg & TIOCM_DSR) && (changed & CH341_BIT_DSR)) ||
534 ((arg & TIOCM_CD) && (changed & CH341_BIT_DCD)) ||
535 ((arg & TIOCM_CTS) && (changed & CH341_BIT_CTS))) {
544 static int ch341_ioctl(struct tty_struct *tty,
545 unsigned int cmd, unsigned long arg)
547 struct usb_serial_port *port = tty->driver_data;
549 dev_dbg(&port->dev, "%s (%d) cmd = 0x%04x\n", __func__, port->number, cmd);
553 dev_dbg(&port->dev, "%s (%d) TIOCMIWAIT\n", __func__, port->number);
554 return wait_modem_info(port, arg);
557 dev_dbg(&port->dev, "%s not supported = 0x%04x\n", __func__, cmd);
564 static int ch341_tiocmget(struct tty_struct *tty)
566 struct usb_serial_port *port = tty->driver_data;
567 struct ch341_private *priv = usb_get_serial_port_data(port);
573 spin_lock_irqsave(&priv->lock, flags);
574 mcr = priv->line_control;
575 status = priv->line_status;
576 spin_unlock_irqrestore(&priv->lock, flags);
578 result = ((mcr & CH341_BIT_DTR) ? TIOCM_DTR : 0)
579 | ((mcr & CH341_BIT_RTS) ? TIOCM_RTS : 0)
580 | ((status & CH341_BIT_CTS) ? TIOCM_CTS : 0)
581 | ((status & CH341_BIT_DSR) ? TIOCM_DSR : 0)
582 | ((status & CH341_BIT_RI) ? TIOCM_RI : 0)
583 | ((status & CH341_BIT_DCD) ? TIOCM_CD : 0);
585 dev_dbg(&port->dev, "%s - result = %x\n", __func__, result);
590 static int ch341_reset_resume(struct usb_serial *serial)
592 struct ch341_private *priv;
594 priv = usb_get_serial_port_data(serial->port[0]);
596 /* reconfigure ch341 serial port after bus-reset */
597 ch341_configure(serial->dev, priv);
602 static struct usb_serial_driver ch341_device = {
604 .owner = THIS_MODULE,
605 .name = "ch341-uart",
607 .id_table = id_table,
610 .dtr_rts = ch341_dtr_rts,
611 .carrier_raised = ch341_carrier_raised,
612 .close = ch341_close,
613 .ioctl = ch341_ioctl,
614 .set_termios = ch341_set_termios,
615 .break_ctl = ch341_break_ctl,
616 .tiocmget = ch341_tiocmget,
617 .tiocmset = ch341_tiocmset,
618 .read_int_callback = ch341_read_int_callback,
619 .port_probe = ch341_port_probe,
620 .port_remove = ch341_port_remove,
621 .reset_resume = ch341_reset_resume,
624 static struct usb_serial_driver * const serial_drivers[] = {
628 module_usb_serial_driver(serial_drivers, id_table);
630 MODULE_LICENSE("GPL");