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_WRITE_REG 0x9A
65 #define CH341_REQ_READ_REG 0x95
66 #define CH341_REG_BREAK1 0x05
67 #define CH341_REG_BREAK2 0x18
68 #define CH341_NBREAK_BITS_REG1 0x01
69 #define CH341_NBREAK_BITS_REG2 0x40
72 static const struct usb_device_id id_table
[] = {
73 { USB_DEVICE(0x4348, 0x5523) },
74 { USB_DEVICE(0x1a86, 0x7523) },
75 { USB_DEVICE(0x1a86, 0x5523) },
78 MODULE_DEVICE_TABLE(usb
, id_table
);
80 struct ch341_private
{
81 spinlock_t lock
; /* access lock */
82 unsigned baud_rate
; /* set baud rate */
83 u8 line_control
; /* set line control value RTS/DTR */
84 u8 line_status
; /* active status of modem control inputs */
87 static void ch341_set_termios(struct tty_struct
*tty
,
88 struct usb_serial_port
*port
,
89 struct ktermios
*old_termios
);
91 static int ch341_control_out(struct usb_device
*dev
, u8 request
,
96 dev_dbg(&dev
->dev
, "ch341_control_out(%02x,%02x,%04x,%04x)\n",
97 USB_DIR_OUT
|0x40, (int)request
, (int)value
, (int)index
);
99 r
= usb_control_msg(dev
, usb_sndctrlpipe(dev
, 0), request
,
100 USB_TYPE_VENDOR
| USB_RECIP_DEVICE
| USB_DIR_OUT
,
101 value
, index
, NULL
, 0, DEFAULT_TIMEOUT
);
106 static int ch341_control_in(struct usb_device
*dev
,
107 u8 request
, u16 value
, u16 index
,
108 char *buf
, unsigned bufsize
)
112 dev_dbg(&dev
->dev
, "ch341_control_in(%02x,%02x,%04x,%04x,%p,%u)\n",
113 USB_DIR_IN
|0x40, (int)request
, (int)value
, (int)index
, buf
,
116 r
= usb_control_msg(dev
, usb_rcvctrlpipe(dev
, 0), request
,
117 USB_TYPE_VENDOR
| USB_RECIP_DEVICE
| USB_DIR_IN
,
118 value
, index
, buf
, bufsize
, DEFAULT_TIMEOUT
);
122 static int ch341_set_baudrate(struct usb_device
*dev
,
123 struct ch341_private
*priv
)
127 unsigned long factor
;
130 if (!priv
->baud_rate
)
132 factor
= (CH341_BAUDBASE_FACTOR
/ priv
->baud_rate
);
133 divisor
= CH341_BAUDBASE_DIVMAX
;
135 while ((factor
> 0xfff0) && divisor
) {
143 factor
= 0x10000 - factor
;
144 a
= (factor
& 0xff00) | divisor
;
147 r
= ch341_control_out(dev
, 0x9a, 0x1312, a
);
149 r
= ch341_control_out(dev
, 0x9a, 0x0f2c, b
);
154 static int ch341_set_handshake(struct usb_device
*dev
, u8 control
)
156 return ch341_control_out(dev
, 0xa4, ~control
, 0);
159 static int ch341_get_status(struct usb_device
*dev
, struct ch341_private
*priv
)
163 const unsigned size
= 8;
166 buffer
= kmalloc(size
, GFP_KERNEL
);
170 r
= ch341_control_in(dev
, 0x95, 0x0706, 0, buffer
, size
);
174 /* setup the private status if available */
177 spin_lock_irqsave(&priv
->lock
, flags
);
178 priv
->line_status
= (~(*buffer
)) & CH341_BITS_MODEM_STAT
;
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 priv
->baud_rate
= DEFAULT_BAUD_RATE
;
257 r
= ch341_configure(port
->serial
->dev
, priv
);
261 usb_set_serial_port_data(port
, priv
);
268 static int ch341_port_remove(struct usb_serial_port
*port
)
270 struct ch341_private
*priv
;
272 priv
= usb_get_serial_port_data(port
);
278 static int ch341_carrier_raised(struct usb_serial_port
*port
)
280 struct ch341_private
*priv
= usb_get_serial_port_data(port
);
281 if (priv
->line_status
& CH341_BIT_DCD
)
286 static void ch341_dtr_rts(struct usb_serial_port
*port
, int on
)
288 struct ch341_private
*priv
= usb_get_serial_port_data(port
);
291 /* drop DTR and RTS */
292 spin_lock_irqsave(&priv
->lock
, flags
);
294 priv
->line_control
|= CH341_BIT_RTS
| CH341_BIT_DTR
;
296 priv
->line_control
&= ~(CH341_BIT_RTS
| CH341_BIT_DTR
);
297 spin_unlock_irqrestore(&priv
->lock
, flags
);
298 ch341_set_handshake(port
->serial
->dev
, priv
->line_control
);
301 static void ch341_close(struct usb_serial_port
*port
)
303 usb_serial_generic_close(port
);
304 usb_kill_urb(port
->interrupt_in_urb
);
308 /* open this device, set default parameters */
309 static int ch341_open(struct tty_struct
*tty
, struct usb_serial_port
*port
)
311 struct usb_serial
*serial
= port
->serial
;
312 struct ch341_private
*priv
= usb_get_serial_port_data(port
);
315 r
= ch341_configure(serial
->dev
, priv
);
320 ch341_set_termios(tty
, port
, NULL
);
322 dev_dbg(&port
->dev
, "%s - submitting interrupt urb\n", __func__
);
323 r
= usb_submit_urb(port
->interrupt_in_urb
, GFP_KERNEL
);
325 dev_err(&port
->dev
, "%s - failed to submit interrupt urb: %d\n",
330 r
= usb_serial_generic_open(tty
, port
);
335 /* Old_termios contains the original termios settings and
336 * tty->termios contains the new setting to be used.
338 static void ch341_set_termios(struct tty_struct
*tty
,
339 struct usb_serial_port
*port
, struct ktermios
*old_termios
)
341 struct ch341_private
*priv
= usb_get_serial_port_data(port
);
345 baud_rate
= tty_get_baud_rate(tty
);
347 priv
->baud_rate
= baud_rate
;
350 spin_lock_irqsave(&priv
->lock
, flags
);
351 priv
->line_control
|= (CH341_BIT_DTR
| CH341_BIT_RTS
);
352 spin_unlock_irqrestore(&priv
->lock
, flags
);
353 ch341_set_baudrate(port
->serial
->dev
, priv
);
355 spin_lock_irqsave(&priv
->lock
, flags
);
356 priv
->line_control
&= ~(CH341_BIT_DTR
| CH341_BIT_RTS
);
357 spin_unlock_irqrestore(&priv
->lock
, flags
);
360 ch341_set_handshake(port
->serial
->dev
, priv
->line_control
);
363 * (cflag & CSIZE) : data bits [5, 8]
364 * (cflag & PARENB) : parity {NONE, EVEN, ODD}
365 * (cflag & CSTOPB) : stop bits [1, 2]
369 static void ch341_break_ctl(struct tty_struct
*tty
, int break_state
)
371 const uint16_t ch341_break_reg
=
372 CH341_REG_BREAK1
| ((uint16_t) CH341_REG_BREAK2
<< 8);
373 struct usb_serial_port
*port
= tty
->driver_data
;
375 uint16_t reg_contents
;
378 break_reg
= kmalloc(2, GFP_KERNEL
);
382 r
= ch341_control_in(port
->serial
->dev
, CH341_REQ_READ_REG
,
383 ch341_break_reg
, 0, break_reg
, 2);
385 dev_err(&port
->dev
, "%s - USB control read error (%d)\n",
389 dev_dbg(&port
->dev
, "%s - initial ch341 break register contents - reg1: %x, reg2: %x\n",
390 __func__
, break_reg
[0], break_reg
[1]);
391 if (break_state
!= 0) {
392 dev_dbg(&port
->dev
, "%s - Enter break state requested\n", __func__
);
393 break_reg
[0] &= ~CH341_NBREAK_BITS_REG1
;
394 break_reg
[1] &= ~CH341_NBREAK_BITS_REG2
;
396 dev_dbg(&port
->dev
, "%s - Leave break state requested\n", __func__
);
397 break_reg
[0] |= CH341_NBREAK_BITS_REG1
;
398 break_reg
[1] |= CH341_NBREAK_BITS_REG2
;
400 dev_dbg(&port
->dev
, "%s - New ch341 break register contents - reg1: %x, reg2: %x\n",
401 __func__
, break_reg
[0], break_reg
[1]);
402 reg_contents
= get_unaligned_le16(break_reg
);
403 r
= ch341_control_out(port
->serial
->dev
, CH341_REQ_WRITE_REG
,
404 ch341_break_reg
, reg_contents
);
406 dev_err(&port
->dev
, "%s - USB control write error (%d)\n",
412 static int ch341_tiocmset(struct tty_struct
*tty
,
413 unsigned int set
, unsigned int clear
)
415 struct usb_serial_port
*port
= tty
->driver_data
;
416 struct ch341_private
*priv
= usb_get_serial_port_data(port
);
420 spin_lock_irqsave(&priv
->lock
, flags
);
422 priv
->line_control
|= CH341_BIT_RTS
;
424 priv
->line_control
|= CH341_BIT_DTR
;
425 if (clear
& TIOCM_RTS
)
426 priv
->line_control
&= ~CH341_BIT_RTS
;
427 if (clear
& TIOCM_DTR
)
428 priv
->line_control
&= ~CH341_BIT_DTR
;
429 control
= priv
->line_control
;
430 spin_unlock_irqrestore(&priv
->lock
, flags
);
432 return ch341_set_handshake(port
->serial
->dev
, control
);
435 static void ch341_update_line_status(struct usb_serial_port
*port
,
436 unsigned char *data
, size_t len
)
438 struct ch341_private
*priv
= usb_get_serial_port_data(port
);
439 struct tty_struct
*tty
;
447 status
= ~data
[2] & CH341_BITS_MODEM_STAT
;
449 spin_lock_irqsave(&priv
->lock
, flags
);
450 delta
= status
^ priv
->line_status
;
451 priv
->line_status
= status
;
452 spin_unlock_irqrestore(&priv
->lock
, flags
);
454 if (data
[1] & CH341_MULT_STAT
)
455 dev_dbg(&port
->dev
, "%s - multiple status change\n", __func__
);
460 if (delta
& CH341_BIT_CTS
)
462 if (delta
& CH341_BIT_DSR
)
464 if (delta
& CH341_BIT_RI
)
466 if (delta
& CH341_BIT_DCD
) {
468 tty
= tty_port_tty_get(&port
->port
);
470 usb_serial_handle_dcd_change(port
, tty
,
471 status
& CH341_BIT_DCD
);
476 wake_up_interruptible(&port
->port
.delta_msr_wait
);
479 static void ch341_read_int_callback(struct urb
*urb
)
481 struct usb_serial_port
*port
= urb
->context
;
482 unsigned char *data
= urb
->transfer_buffer
;
483 unsigned int len
= urb
->actual_length
;
486 switch (urb
->status
) {
493 /* this urb is terminated, clean up */
494 dev_dbg(&urb
->dev
->dev
, "%s - urb shutting down: %d\n",
495 __func__
, urb
->status
);
498 dev_dbg(&urb
->dev
->dev
, "%s - nonzero urb status: %d\n",
499 __func__
, urb
->status
);
503 usb_serial_debug_data(&port
->dev
, __func__
, len
, data
);
504 ch341_update_line_status(port
, data
, len
);
506 status
= usb_submit_urb(urb
, GFP_ATOMIC
);
508 dev_err(&urb
->dev
->dev
, "%s - usb_submit_urb failed: %d\n",
513 static int ch341_tiocmget(struct tty_struct
*tty
)
515 struct usb_serial_port
*port
= tty
->driver_data
;
516 struct ch341_private
*priv
= usb_get_serial_port_data(port
);
522 spin_lock_irqsave(&priv
->lock
, flags
);
523 mcr
= priv
->line_control
;
524 status
= priv
->line_status
;
525 spin_unlock_irqrestore(&priv
->lock
, flags
);
527 result
= ((mcr
& CH341_BIT_DTR
) ? TIOCM_DTR
: 0)
528 | ((mcr
& CH341_BIT_RTS
) ? TIOCM_RTS
: 0)
529 | ((status
& CH341_BIT_CTS
) ? TIOCM_CTS
: 0)
530 | ((status
& CH341_BIT_DSR
) ? TIOCM_DSR
: 0)
531 | ((status
& CH341_BIT_RI
) ? TIOCM_RI
: 0)
532 | ((status
& CH341_BIT_DCD
) ? TIOCM_CD
: 0);
534 dev_dbg(&port
->dev
, "%s - result = %x\n", __func__
, result
);
539 static int ch341_reset_resume(struct usb_serial
*serial
)
541 struct ch341_private
*priv
;
543 priv
= usb_get_serial_port_data(serial
->port
[0]);
545 /* reconfigure ch341 serial port after bus-reset */
546 ch341_configure(serial
->dev
, priv
);
551 static struct usb_serial_driver ch341_device
= {
553 .owner
= THIS_MODULE
,
554 .name
= "ch341-uart",
556 .id_table
= id_table
,
559 .dtr_rts
= ch341_dtr_rts
,
560 .carrier_raised
= ch341_carrier_raised
,
561 .close
= ch341_close
,
562 .set_termios
= ch341_set_termios
,
563 .break_ctl
= ch341_break_ctl
,
564 .tiocmget
= ch341_tiocmget
,
565 .tiocmset
= ch341_tiocmset
,
566 .tiocmiwait
= usb_serial_generic_tiocmiwait
,
567 .read_int_callback
= ch341_read_int_callback
,
568 .port_probe
= ch341_port_probe
,
569 .port_remove
= ch341_port_remove
,
570 .reset_resume
= ch341_reset_resume
,
573 static struct usb_serial_driver
* const serial_drivers
[] = {
577 module_usb_serial_driver(serial_drivers
, id_table
);
579 MODULE_LICENSE("GPL");