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");