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(0x4348, 0x5523) },
87 { USB_DEVICE(0x1a86, 0x7523) },
88 { USB_DEVICE(0x1a86, 0x5523) },
91 MODULE_DEVICE_TABLE(usb, id_table);
93 struct ch341_private {
94 spinlock_t lock; /* access lock */
95 unsigned baud_rate; /* set baud rate */
96 u8 line_control; /* set line control value RTS/DTR */
97 u8 line_status; /* active status of modem control inputs */
100 static void ch341_set_termios(struct tty_struct *tty,
101 struct usb_serial_port *port,
102 struct ktermios *old_termios);
104 static int ch341_control_out(struct usb_device *dev, u8 request,
105 u16 value, u16 index)
109 dev_dbg(&dev->dev, "ch341_control_out(%02x,%02x,%04x,%04x)\n",
110 USB_DIR_OUT|0x40, (int)request, (int)value, (int)index);
112 r = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), request,
113 USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT,
114 value, index, NULL, 0, DEFAULT_TIMEOUT);
116 dev_err(&dev->dev, "failed to send control message: %d\n", r);
121 static int ch341_control_in(struct usb_device *dev,
122 u8 request, u16 value, u16 index,
123 char *buf, unsigned bufsize)
127 dev_dbg(&dev->dev, "ch341_control_in(%02x,%02x,%04x,%04x,%p,%u)\n",
128 USB_DIR_IN|0x40, (int)request, (int)value, (int)index, buf,
131 r = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), request,
132 USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
133 value, index, buf, bufsize, DEFAULT_TIMEOUT);
134 if (r < (int)bufsize) {
137 "short control message received (%d < %u)\n",
142 dev_err(&dev->dev, "failed to receive control message: %d\n",
150 static int ch341_set_baudrate_lcr(struct usb_device *dev,
151 struct ch341_private *priv, u8 lcr)
155 unsigned long factor;
158 if (!priv->baud_rate)
160 factor = (CH341_BAUDBASE_FACTOR / priv->baud_rate);
161 divisor = CH341_BAUDBASE_DIVMAX;
163 while ((factor > 0xfff0) && divisor) {
171 factor = 0x10000 - factor;
172 a = (factor & 0xff00) | divisor;
175 * CH341A buffers data until a full endpoint-size packet (32 bytes)
176 * has been received unless bit 7 is set.
180 r = ch341_control_out(dev, CH341_REQ_WRITE_REG, 0x1312, a);
184 r = ch341_control_out(dev, CH341_REQ_WRITE_REG, 0x2518, lcr);
191 static int ch341_set_handshake(struct usb_device *dev, u8 control)
193 return ch341_control_out(dev, CH341_REQ_MODEM_CTRL, ~control, 0);
196 static int ch341_get_status(struct usb_device *dev, struct ch341_private *priv)
198 const unsigned int size = 2;
203 buffer = kmalloc(size, GFP_KERNEL);
207 r = ch341_control_in(dev, CH341_REQ_READ_REG, 0x0706, 0, buffer, size);
211 spin_lock_irqsave(&priv->lock, flags);
212 priv->line_status = (~(*buffer)) & CH341_BITS_MODEM_STAT;
213 spin_unlock_irqrestore(&priv->lock, flags);
219 /* -------------------------------------------------------------------------- */
221 static int ch341_configure(struct usb_device *dev, struct ch341_private *priv)
223 const unsigned int size = 2;
227 buffer = kmalloc(size, GFP_KERNEL);
231 /* expect two bytes 0x27 0x00 */
232 r = ch341_control_in(dev, CH341_REQ_READ_VERSION, 0, 0, buffer, size);
236 r = ch341_control_out(dev, CH341_REQ_SERIAL_INIT, 0, 0);
240 /* expect two bytes 0x56 0x00 */
241 r = ch341_control_in(dev, CH341_REQ_READ_REG, 0x2518, 0, buffer, size);
245 r = ch341_control_out(dev, CH341_REQ_WRITE_REG, 0x2518, 0x0050);
249 r = ch341_set_baudrate_lcr(dev, priv, 0);
253 r = ch341_set_handshake(dev, priv->line_control);
259 static int ch341_port_probe(struct usb_serial_port *port)
261 struct ch341_private *priv;
264 priv = kzalloc(sizeof(struct ch341_private), GFP_KERNEL);
268 spin_lock_init(&priv->lock);
269 priv->baud_rate = DEFAULT_BAUD_RATE;
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->line_status & 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->line_control |= CH341_BIT_RTS | CH341_BIT_DTR;
310 priv->line_control &= ~(CH341_BIT_RTS | CH341_BIT_DTR);
311 spin_unlock_irqrestore(&priv->lock, flags);
312 ch341_set_handshake(port->serial->dev, priv->line_control);
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 ctrl = CH341_LCR_ENABLE_RX | CH341_LCR_ENABLE_TX | CH341_LCR_CS8;
378 priv->baud_rate = baud_rate;
380 r = ch341_set_baudrate_lcr(port->serial->dev, priv, ctrl);
381 if (r < 0 && old_termios) {
382 priv->baud_rate = tty_termios_baud_rate(old_termios);
383 tty_termios_copy_hw(&tty->termios, old_termios);
387 spin_lock_irqsave(&priv->lock, flags);
388 if (C_BAUD(tty) == B0)
389 priv->line_control &= ~(CH341_BIT_DTR | CH341_BIT_RTS);
390 else if (old_termios && (old_termios->c_cflag & CBAUD) == B0)
391 priv->line_control |= (CH341_BIT_DTR | CH341_BIT_RTS);
392 spin_unlock_irqrestore(&priv->lock, flags);
395 * (cflag & CSIZE) : data bits [5, 8]
396 * (cflag & PARENB) : parity {NONE, EVEN, ODD}
397 * (cflag & CSTOPB) : stop bits [1, 2]
401 static void ch341_break_ctl(struct tty_struct *tty, int break_state)
403 const uint16_t ch341_break_reg =
404 ((uint16_t) CH341_REG_LCR << 8) | CH341_REG_BREAK;
405 struct usb_serial_port *port = tty->driver_data;
407 uint16_t reg_contents;
410 break_reg = kmalloc(2, GFP_KERNEL);
414 r = ch341_control_in(port->serial->dev, CH341_REQ_READ_REG,
415 ch341_break_reg, 0, break_reg, 2);
417 dev_err(&port->dev, "%s - USB control read error (%d)\n",
421 dev_dbg(&port->dev, "%s - initial ch341 break register contents - reg1: %x, reg2: %x\n",
422 __func__, break_reg[0], break_reg[1]);
423 if (break_state != 0) {
424 dev_dbg(&port->dev, "%s - Enter break state requested\n", __func__);
425 break_reg[0] &= ~CH341_NBREAK_BITS;
426 break_reg[1] &= ~CH341_LCR_ENABLE_TX;
428 dev_dbg(&port->dev, "%s - Leave break state requested\n", __func__);
429 break_reg[0] |= CH341_NBREAK_BITS;
430 break_reg[1] |= CH341_LCR_ENABLE_TX;
432 dev_dbg(&port->dev, "%s - New ch341 break register contents - reg1: %x, reg2: %x\n",
433 __func__, break_reg[0], break_reg[1]);
434 reg_contents = get_unaligned_le16(break_reg);
435 r = ch341_control_out(port->serial->dev, CH341_REQ_WRITE_REG,
436 ch341_break_reg, reg_contents);
438 dev_err(&port->dev, "%s - USB control write error (%d)\n",
444 static int ch341_tiocmset(struct tty_struct *tty,
445 unsigned int set, unsigned int clear)
447 struct usb_serial_port *port = tty->driver_data;
448 struct ch341_private *priv = usb_get_serial_port_data(port);
452 spin_lock_irqsave(&priv->lock, flags);
454 priv->line_control |= CH341_BIT_RTS;
456 priv->line_control |= CH341_BIT_DTR;
457 if (clear & TIOCM_RTS)
458 priv->line_control &= ~CH341_BIT_RTS;
459 if (clear & TIOCM_DTR)
460 priv->line_control &= ~CH341_BIT_DTR;
461 control = priv->line_control;
462 spin_unlock_irqrestore(&priv->lock, flags);
464 return ch341_set_handshake(port->serial->dev, control);
467 static void ch341_update_line_status(struct usb_serial_port *port,
468 unsigned char *data, size_t len)
470 struct ch341_private *priv = usb_get_serial_port_data(port);
471 struct tty_struct *tty;
479 status = ~data[2] & CH341_BITS_MODEM_STAT;
481 spin_lock_irqsave(&priv->lock, flags);
482 delta = status ^ priv->line_status;
483 priv->line_status = status;
484 spin_unlock_irqrestore(&priv->lock, flags);
486 if (data[1] & CH341_MULT_STAT)
487 dev_dbg(&port->dev, "%s - multiple status change\n", __func__);
492 if (delta & CH341_BIT_CTS)
494 if (delta & CH341_BIT_DSR)
496 if (delta & CH341_BIT_RI)
498 if (delta & CH341_BIT_DCD) {
500 tty = tty_port_tty_get(&port->port);
502 usb_serial_handle_dcd_change(port, tty,
503 status & CH341_BIT_DCD);
508 wake_up_interruptible(&port->port.delta_msr_wait);
511 static void ch341_read_int_callback(struct urb *urb)
513 struct usb_serial_port *port = urb->context;
514 unsigned char *data = urb->transfer_buffer;
515 unsigned int len = urb->actual_length;
518 switch (urb->status) {
525 /* this urb is terminated, clean up */
526 dev_dbg(&urb->dev->dev, "%s - urb shutting down: %d\n",
527 __func__, urb->status);
530 dev_dbg(&urb->dev->dev, "%s - nonzero urb status: %d\n",
531 __func__, urb->status);
535 usb_serial_debug_data(&port->dev, __func__, len, data);
536 ch341_update_line_status(port, data, len);
538 status = usb_submit_urb(urb, GFP_ATOMIC);
540 dev_err(&urb->dev->dev, "%s - usb_submit_urb failed: %d\n",
545 static int ch341_tiocmget(struct tty_struct *tty)
547 struct usb_serial_port *port = tty->driver_data;
548 struct ch341_private *priv = usb_get_serial_port_data(port);
554 spin_lock_irqsave(&priv->lock, flags);
555 mcr = priv->line_control;
556 status = priv->line_status;
557 spin_unlock_irqrestore(&priv->lock, flags);
559 result = ((mcr & CH341_BIT_DTR) ? TIOCM_DTR : 0)
560 | ((mcr & CH341_BIT_RTS) ? TIOCM_RTS : 0)
561 | ((status & CH341_BIT_CTS) ? TIOCM_CTS : 0)
562 | ((status & CH341_BIT_DSR) ? TIOCM_DSR : 0)
563 | ((status & CH341_BIT_RI) ? TIOCM_RI : 0)
564 | ((status & CH341_BIT_DCD) ? TIOCM_CD : 0);
566 dev_dbg(&port->dev, "%s - result = %x\n", __func__, result);
571 static int ch341_reset_resume(struct usb_serial *serial)
573 struct usb_serial_port *port = serial->port[0];
574 struct ch341_private *priv = usb_get_serial_port_data(port);
577 /* reconfigure ch341 serial port after bus-reset */
578 ch341_configure(serial->dev, priv);
580 if (port->port.flags & ASYNC_INITIALIZED) {
581 ret = usb_submit_urb(port->interrupt_in_urb, GFP_NOIO);
583 dev_err(&port->dev, "failed to submit interrupt urb: %d\n",
588 ret = ch341_get_status(port->serial->dev, priv);
590 dev_err(&port->dev, "failed to read modem status: %d\n",
595 return usb_serial_generic_resume(serial);
598 static struct usb_serial_driver ch341_device = {
600 .owner = THIS_MODULE,
601 .name = "ch341-uart",
603 .id_table = id_table,
606 .dtr_rts = ch341_dtr_rts,
607 .carrier_raised = ch341_carrier_raised,
608 .close = ch341_close,
609 .set_termios = ch341_set_termios,
610 .break_ctl = ch341_break_ctl,
611 .tiocmget = ch341_tiocmget,
612 .tiocmset = ch341_tiocmset,
613 .tiocmiwait = usb_serial_generic_tiocmiwait,
614 .read_int_callback = ch341_read_int_callback,
615 .port_probe = ch341_port_probe,
616 .port_remove = ch341_port_remove,
617 .reset_resume = ch341_reset_resume,
620 static struct usb_serial_driver * const serial_drivers[] = {
624 module_usb_serial_driver(serial_drivers, id_table);
626 MODULE_LICENSE("GPL");