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
);
119 static int ch341_control_in(struct usb_device
*dev
,
120 u8 request
, u16 value
, u16 index
,
121 char *buf
, unsigned bufsize
)
125 dev_dbg(&dev
->dev
, "ch341_control_in(%02x,%02x,%04x,%04x,%p,%u)\n",
126 USB_DIR_IN
|0x40, (int)request
, (int)value
, (int)index
, buf
,
129 r
= usb_control_msg(dev
, usb_rcvctrlpipe(dev
, 0), request
,
130 USB_TYPE_VENDOR
| USB_RECIP_DEVICE
| USB_DIR_IN
,
131 value
, index
, buf
, bufsize
, DEFAULT_TIMEOUT
);
135 static int ch341_init_set_baudrate(struct usb_device
*dev
,
136 struct ch341_private
*priv
, unsigned ctrl
)
140 unsigned long factor
;
143 if (!priv
->baud_rate
)
145 factor
= (CH341_BAUDBASE_FACTOR
/ priv
->baud_rate
);
146 divisor
= CH341_BAUDBASE_DIVMAX
;
148 while ((factor
> 0xfff0) && divisor
) {
156 factor
= 0x10000 - factor
;
157 a
= (factor
& 0xff00) | divisor
;
159 /* 0x9c is "enable SFR_UART Control register and timer" */
160 r
= ch341_control_out(dev
, CH341_REQ_SERIAL_INIT
,
161 0x9c | (ctrl
<< 8), a
| 0x80);
166 static int ch341_set_handshake(struct usb_device
*dev
, u8 control
)
168 return ch341_control_out(dev
, CH341_REQ_MODEM_CTRL
, ~control
, 0);
171 static int ch341_get_status(struct usb_device
*dev
, struct ch341_private
*priv
)
175 const unsigned size
= 8;
178 buffer
= kmalloc(size
, GFP_KERNEL
);
182 r
= ch341_control_in(dev
, CH341_REQ_READ_REG
, 0x0706, 0, buffer
, size
);
186 /* setup the private status if available */
189 spin_lock_irqsave(&priv
->lock
, flags
);
190 priv
->line_status
= (~(*buffer
)) & CH341_BITS_MODEM_STAT
;
191 spin_unlock_irqrestore(&priv
->lock
, flags
);
199 /* -------------------------------------------------------------------------- */
201 static int ch341_configure(struct usb_device
*dev
, struct ch341_private
*priv
)
205 const unsigned size
= 8;
207 buffer
= kmalloc(size
, GFP_KERNEL
);
211 /* expect two bytes 0x27 0x00 */
212 r
= ch341_control_in(dev
, CH341_REQ_READ_VERSION
, 0, 0, buffer
, size
);
215 dev_dbg(&dev
->dev
, "Chip version: 0x%02x\n", buffer
[0]);
217 r
= ch341_control_out(dev
, CH341_REQ_SERIAL_INIT
, 0, 0);
221 /* expect two bytes 0x56 0x00 */
222 r
= ch341_control_in(dev
, CH341_REQ_READ_REG
, 0x2518, 0, buffer
, size
);
226 r
= ch341_control_out(dev
, CH341_REQ_WRITE_REG
, 0x2518, 0x0050);
230 /* expect 0xff 0xee */
231 r
= ch341_get_status(dev
, priv
);
235 r
= ch341_init_set_baudrate(dev
, priv
, 0);
239 r
= ch341_set_handshake(dev
, priv
->line_control
);
243 /* expect 0x9f 0xee */
244 r
= ch341_get_status(dev
, priv
);
250 static int ch341_port_probe(struct usb_serial_port
*port
)
252 struct ch341_private
*priv
;
255 priv
= kzalloc(sizeof(struct ch341_private
), GFP_KERNEL
);
259 spin_lock_init(&priv
->lock
);
260 priv
->baud_rate
= DEFAULT_BAUD_RATE
;
261 priv
->line_control
= CH341_BIT_RTS
| CH341_BIT_DTR
;
263 r
= ch341_configure(port
->serial
->dev
, priv
);
267 usb_set_serial_port_data(port
, priv
);
274 static int ch341_port_remove(struct usb_serial_port
*port
)
276 struct ch341_private
*priv
;
278 priv
= usb_get_serial_port_data(port
);
284 static int ch341_carrier_raised(struct usb_serial_port
*port
)
286 struct ch341_private
*priv
= usb_get_serial_port_data(port
);
287 if (priv
->line_status
& CH341_BIT_DCD
)
292 static void ch341_dtr_rts(struct usb_serial_port
*port
, int on
)
294 struct ch341_private
*priv
= usb_get_serial_port_data(port
);
297 /* drop DTR and RTS */
298 spin_lock_irqsave(&priv
->lock
, flags
);
300 priv
->line_control
|= CH341_BIT_RTS
| CH341_BIT_DTR
;
302 priv
->line_control
&= ~(CH341_BIT_RTS
| CH341_BIT_DTR
);
303 spin_unlock_irqrestore(&priv
->lock
, flags
);
304 ch341_set_handshake(port
->serial
->dev
, priv
->line_control
);
307 static void ch341_close(struct usb_serial_port
*port
)
309 usb_serial_generic_close(port
);
310 usb_kill_urb(port
->interrupt_in_urb
);
314 /* open this device, set default parameters */
315 static int ch341_open(struct tty_struct
*tty
, struct usb_serial_port
*port
)
317 struct usb_serial
*serial
= port
->serial
;
318 struct ch341_private
*priv
= usb_get_serial_port_data(port
);
321 r
= ch341_configure(serial
->dev
, priv
);
326 ch341_set_termios(tty
, port
, NULL
);
328 dev_dbg(&port
->dev
, "%s - submitting interrupt urb\n", __func__
);
329 r
= usb_submit_urb(port
->interrupt_in_urb
, GFP_KERNEL
);
331 dev_err(&port
->dev
, "%s - failed to submit interrupt urb: %d\n",
336 r
= usb_serial_generic_open(tty
, port
);
341 /* Old_termios contains the original termios settings and
342 * tty->termios contains the new setting to be used.
344 static void ch341_set_termios(struct tty_struct
*tty
,
345 struct usb_serial_port
*port
, struct ktermios
*old_termios
)
347 struct ch341_private
*priv
= usb_get_serial_port_data(port
);
353 /* redundant changes may cause the chip to lose bytes */
354 if (old_termios
&& !tty_termios_hw_change(&tty
->termios
, old_termios
))
357 baud_rate
= tty_get_baud_rate(tty
);
359 priv
->baud_rate
= baud_rate
;
360 ctrl
= CH341_LCR_ENABLE_RX
| CH341_LCR_ENABLE_TX
;
362 switch (C_CSIZE(tty
)) {
364 ctrl
|= CH341_LCR_CS5
;
367 ctrl
|= CH341_LCR_CS6
;
370 ctrl
|= CH341_LCR_CS7
;
373 ctrl
|= CH341_LCR_CS8
;
378 ctrl
|= CH341_LCR_ENABLE_PAR
;
379 if (C_PARODD(tty
) == 0)
380 ctrl
|= CH341_LCR_PAR_EVEN
;
382 ctrl
|= CH341_LCR_MARK_SPACE
;
386 ctrl
|= CH341_LCR_STOP_BITS_2
;
389 spin_lock_irqsave(&priv
->lock
, flags
);
390 priv
->line_control
|= (CH341_BIT_DTR
| CH341_BIT_RTS
);
391 spin_unlock_irqrestore(&priv
->lock
, flags
);
392 r
= ch341_init_set_baudrate(port
->serial
->dev
, priv
, ctrl
);
393 if (r
< 0 && old_termios
) {
394 priv
->baud_rate
= tty_termios_baud_rate(old_termios
);
395 tty_termios_copy_hw(&tty
->termios
, old_termios
);
398 spin_lock_irqsave(&priv
->lock
, flags
);
399 priv
->line_control
&= ~(CH341_BIT_DTR
| CH341_BIT_RTS
);
400 spin_unlock_irqrestore(&priv
->lock
, flags
);
403 ch341_set_handshake(port
->serial
->dev
, priv
->line_control
);
407 static void ch341_break_ctl(struct tty_struct
*tty
, int break_state
)
409 const uint16_t ch341_break_reg
=
410 ((uint16_t) CH341_REG_LCR
<< 8) | CH341_REG_BREAK
;
411 struct usb_serial_port
*port
= tty
->driver_data
;
413 uint16_t reg_contents
;
416 break_reg
= kmalloc(2, GFP_KERNEL
);
420 r
= ch341_control_in(port
->serial
->dev
, CH341_REQ_READ_REG
,
421 ch341_break_reg
, 0, break_reg
, 2);
423 dev_err(&port
->dev
, "%s - USB control read error (%d)\n",
427 dev_dbg(&port
->dev
, "%s - initial ch341 break register contents - reg1: %x, reg2: %x\n",
428 __func__
, break_reg
[0], break_reg
[1]);
429 if (break_state
!= 0) {
430 dev_dbg(&port
->dev
, "%s - Enter break state requested\n", __func__
);
431 break_reg
[0] &= ~CH341_NBREAK_BITS
;
432 break_reg
[1] &= ~CH341_LCR_ENABLE_TX
;
434 dev_dbg(&port
->dev
, "%s - Leave break state requested\n", __func__
);
435 break_reg
[0] |= CH341_NBREAK_BITS
;
436 break_reg
[1] |= CH341_LCR_ENABLE_TX
;
438 dev_dbg(&port
->dev
, "%s - New ch341 break register contents - reg1: %x, reg2: %x\n",
439 __func__
, break_reg
[0], break_reg
[1]);
440 reg_contents
= get_unaligned_le16(break_reg
);
441 r
= ch341_control_out(port
->serial
->dev
, CH341_REQ_WRITE_REG
,
442 ch341_break_reg
, reg_contents
);
444 dev_err(&port
->dev
, "%s - USB control write error (%d)\n",
450 static int ch341_tiocmset(struct tty_struct
*tty
,
451 unsigned int set
, unsigned int clear
)
453 struct usb_serial_port
*port
= tty
->driver_data
;
454 struct ch341_private
*priv
= usb_get_serial_port_data(port
);
458 spin_lock_irqsave(&priv
->lock
, flags
);
460 priv
->line_control
|= CH341_BIT_RTS
;
462 priv
->line_control
|= CH341_BIT_DTR
;
463 if (clear
& TIOCM_RTS
)
464 priv
->line_control
&= ~CH341_BIT_RTS
;
465 if (clear
& TIOCM_DTR
)
466 priv
->line_control
&= ~CH341_BIT_DTR
;
467 control
= priv
->line_control
;
468 spin_unlock_irqrestore(&priv
->lock
, flags
);
470 return ch341_set_handshake(port
->serial
->dev
, control
);
473 static void ch341_update_line_status(struct usb_serial_port
*port
,
474 unsigned char *data
, size_t len
)
476 struct ch341_private
*priv
= usb_get_serial_port_data(port
);
477 struct tty_struct
*tty
;
485 status
= ~data
[2] & CH341_BITS_MODEM_STAT
;
487 spin_lock_irqsave(&priv
->lock
, flags
);
488 delta
= status
^ priv
->line_status
;
489 priv
->line_status
= status
;
490 spin_unlock_irqrestore(&priv
->lock
, flags
);
492 if (data
[1] & CH341_MULT_STAT
)
493 dev_dbg(&port
->dev
, "%s - multiple status change\n", __func__
);
498 if (delta
& CH341_BIT_CTS
)
500 if (delta
& CH341_BIT_DSR
)
502 if (delta
& CH341_BIT_RI
)
504 if (delta
& CH341_BIT_DCD
) {
506 tty
= tty_port_tty_get(&port
->port
);
508 usb_serial_handle_dcd_change(port
, tty
,
509 status
& CH341_BIT_DCD
);
514 wake_up_interruptible(&port
->port
.delta_msr_wait
);
517 static void ch341_read_int_callback(struct urb
*urb
)
519 struct usb_serial_port
*port
= urb
->context
;
520 unsigned char *data
= urb
->transfer_buffer
;
521 unsigned int len
= urb
->actual_length
;
524 switch (urb
->status
) {
531 /* this urb is terminated, clean up */
532 dev_dbg(&urb
->dev
->dev
, "%s - urb shutting down: %d\n",
533 __func__
, urb
->status
);
536 dev_dbg(&urb
->dev
->dev
, "%s - nonzero urb status: %d\n",
537 __func__
, urb
->status
);
541 usb_serial_debug_data(&port
->dev
, __func__
, len
, data
);
542 ch341_update_line_status(port
, data
, len
);
544 status
= usb_submit_urb(urb
, GFP_ATOMIC
);
546 dev_err(&urb
->dev
->dev
, "%s - usb_submit_urb failed: %d\n",
551 static int ch341_tiocmget(struct tty_struct
*tty
)
553 struct usb_serial_port
*port
= tty
->driver_data
;
554 struct ch341_private
*priv
= usb_get_serial_port_data(port
);
560 spin_lock_irqsave(&priv
->lock
, flags
);
561 mcr
= priv
->line_control
;
562 status
= priv
->line_status
;
563 spin_unlock_irqrestore(&priv
->lock
, flags
);
565 result
= ((mcr
& CH341_BIT_DTR
) ? TIOCM_DTR
: 0)
566 | ((mcr
& CH341_BIT_RTS
) ? TIOCM_RTS
: 0)
567 | ((status
& CH341_BIT_CTS
) ? TIOCM_CTS
: 0)
568 | ((status
& CH341_BIT_DSR
) ? TIOCM_DSR
: 0)
569 | ((status
& CH341_BIT_RI
) ? TIOCM_RI
: 0)
570 | ((status
& CH341_BIT_DCD
) ? TIOCM_CD
: 0);
572 dev_dbg(&port
->dev
, "%s - result = %x\n", __func__
, result
);
577 static int ch341_reset_resume(struct usb_serial
*serial
)
579 struct ch341_private
*priv
;
581 priv
= usb_get_serial_port_data(serial
->port
[0]);
583 /* reconfigure ch341 serial port after bus-reset */
584 ch341_configure(serial
->dev
, priv
);
589 static struct usb_serial_driver ch341_device
= {
591 .owner
= THIS_MODULE
,
592 .name
= "ch341-uart",
594 .id_table
= id_table
,
597 .dtr_rts
= ch341_dtr_rts
,
598 .carrier_raised
= ch341_carrier_raised
,
599 .close
= ch341_close
,
600 .set_termios
= ch341_set_termios
,
601 .break_ctl
= ch341_break_ctl
,
602 .tiocmget
= ch341_tiocmget
,
603 .tiocmset
= ch341_tiocmset
,
604 .tiocmiwait
= usb_serial_generic_tiocmiwait
,
605 .read_int_callback
= ch341_read_int_callback
,
606 .port_probe
= ch341_port_probe
,
607 .port_remove
= ch341_port_remove
,
608 .reset_resume
= ch341_reset_resume
,
611 static struct usb_serial_driver
* const serial_drivers
[] = {
615 module_usb_serial_driver(serial_drivers
, id_table
);
617 MODULE_LICENSE("GPL");