2 * Copyright 2007, Frank A Kingswood <frank@kingswood-consulting.co.uk>
4 * ch341.c implements a serial port driver for the Winchiphead CH341.
6 * The CH341 device can be used to implement an RS232 asynchronous
7 * serial port, an IEEE-1284 parallel printer port or a memory-like
8 * interface. In all cases the CH341 supports an I2C interface as well.
9 * This driver only supports the asynchronous serial interface.
11 * This program is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU General Public License version
13 * 2 as published by the Free Software Foundation.
16 #include <linux/kernel.h>
17 #include <linux/init.h>
18 #include <linux/tty.h>
19 #include <linux/module.h>
20 #include <linux/usb.h>
21 #include <linux/usb/serial.h>
22 #include <linux/serial.h>
24 #define DEFAULT_BAUD_RATE 2400
25 #define DEFAULT_TIMEOUT 1000
29 static struct usb_device_id id_table
[] = {
30 { USB_DEVICE(0x4348, 0x5523) },
33 MODULE_DEVICE_TABLE(usb
, id_table
);
35 struct ch341_private
{
41 static int ch341_control_out(struct usb_device
*dev
, u8 request
,
45 dbg("ch341_control_out(%02x,%02x,%04x,%04x)", USB_DIR_OUT
|0x40,
46 (int)request
, (int)value
, (int)index
);
48 r
= usb_control_msg(dev
, usb_sndctrlpipe(dev
, 0), request
,
49 USB_TYPE_VENDOR
| USB_RECIP_DEVICE
| USB_DIR_OUT
,
50 value
, index
, NULL
, 0, DEFAULT_TIMEOUT
);
55 static int ch341_control_in(struct usb_device
*dev
,
56 u8 request
, u16 value
, u16 index
,
57 char *buf
, unsigned bufsize
)
60 dbg("ch341_control_in(%02x,%02x,%04x,%04x,%p,%u)", USB_DIR_IN
|0x40,
61 (int)request
, (int)value
, (int)index
, buf
, (int)bufsize
);
63 r
= usb_control_msg(dev
, usb_rcvctrlpipe(dev
, 0), request
,
64 USB_TYPE_VENDOR
| USB_RECIP_DEVICE
| USB_DIR_IN
,
65 value
, index
, buf
, bufsize
, DEFAULT_TIMEOUT
);
69 static int ch341_set_baudrate(struct usb_device
*dev
,
70 struct ch341_private
*priv
)
75 dbg("ch341_set_baudrate(%d)", priv
->baud_rate
);
76 switch (priv
->baud_rate
) {
105 r
= ch341_control_out(dev
, 0x9a, 0x1312, a
);
107 r
= ch341_control_out(dev
, 0x9a, 0x0f2c, b
);
112 static int ch341_set_handshake(struct usb_device
*dev
,
113 struct ch341_private
*priv
)
115 dbg("ch341_set_handshake(%d,%d)", priv
->dtr
, priv
->rts
);
116 return ch341_control_out(dev
, 0xa4,
117 ~((priv
->dtr
?1<<5:0)|(priv
->rts
?1<<6:0)), 0);
120 static int ch341_get_status(struct usb_device
*dev
)
124 const unsigned size
= 8;
126 dbg("ch341_get_status()");
128 buffer
= kmalloc(size
, GFP_KERNEL
);
132 r
= ch341_control_in(dev
, 0x95, 0x0706, 0, buffer
, size
);
136 /* Not having the datasheet for the CH341, we ignore the bytes returned
137 * from the device. Return error if the device did not respond in time.
145 /* -------------------------------------------------------------------------- */
147 static int ch341_configure(struct usb_device
*dev
, struct ch341_private
*priv
)
151 const unsigned size
= 8;
153 dbg("ch341_configure()");
155 buffer
= kmalloc(size
, GFP_KERNEL
);
159 /* expect two bytes 0x27 0x00 */
160 r
= ch341_control_in(dev
, 0x5f, 0, 0, buffer
, size
);
164 r
= ch341_control_out(dev
, 0xa1, 0, 0);
168 r
= ch341_set_baudrate(dev
, priv
);
172 /* expect two bytes 0x56 0x00 */
173 r
= ch341_control_in(dev
, 0x95, 0x2518, 0, buffer
, size
);
177 r
= ch341_control_out(dev
, 0x9a, 0x2518, 0x0050);
181 /* expect 0xff 0xee */
182 r
= ch341_get_status(dev
);
186 r
= ch341_control_out(dev
, 0xa1, 0x501f, 0xd90a);
190 r
= ch341_set_baudrate(dev
, priv
);
194 r
= ch341_set_handshake(dev
, priv
);
198 /* expect 0x9f 0xee */
199 r
= ch341_get_status(dev
);
205 /* allocate private data */
206 static int ch341_attach(struct usb_serial
*serial
)
208 struct ch341_private
*priv
;
211 dbg("ch341_attach()");
214 priv
= kzalloc(sizeof(struct ch341_private
), GFP_KERNEL
);
218 priv
->baud_rate
= DEFAULT_BAUD_RATE
;
222 r
= ch341_configure(serial
->dev
, priv
);
226 usb_set_serial_port_data(serial
->port
[0], priv
);
233 /* open this device, set default parameters */
234 static int ch341_open(struct usb_serial_port
*port
, struct file
*filp
)
236 struct usb_serial
*serial
= port
->serial
;
237 struct ch341_private
*priv
= usb_get_serial_port_data(serial
->port
[0]);
242 priv
->baud_rate
= DEFAULT_BAUD_RATE
;
246 r
= ch341_configure(serial
->dev
, priv
);
250 r
= ch341_set_handshake(serial
->dev
, priv
);
254 r
= ch341_set_baudrate(serial
->dev
, priv
);
258 r
= usb_serial_generic_open(port
, filp
);
263 /* Old_termios contains the original termios settings and
264 * tty->termios contains the new setting to be used.
266 static void ch341_set_termios(struct usb_serial_port
*port
,
267 struct ktermios
*old_termios
)
269 struct ch341_private
*priv
= usb_get_serial_port_data(port
);
270 struct tty_struct
*tty
= port
->tty
;
273 dbg("ch341_set_termios()");
275 baud_rate
= tty_get_baud_rate(tty
);
284 priv
->baud_rate
= baud_rate
;
287 dbg("Rate %d not supported, using %d",
288 baud_rate
, DEFAULT_BAUD_RATE
);
289 priv
->baud_rate
= DEFAULT_BAUD_RATE
;
292 ch341_set_baudrate(port
->serial
->dev
, priv
);
295 * (cflag & CSIZE) : data bits [5, 8]
296 * (cflag & PARENB) : parity {NONE, EVEN, ODD}
297 * (cflag & CSTOPB) : stop bits [1, 2]
300 /* Copy back the old hardware settings */
301 tty_termios_copy_hw(tty
->termios
, old_termios
);
302 /* And re-encode with the new baud */
303 tty_encode_baud_rate(tty
, baud_rate
, baud_rate
);
306 static struct usb_driver ch341_driver
= {
308 .probe
= usb_serial_probe
,
309 .disconnect
= usb_serial_disconnect
,
310 .id_table
= id_table
,
314 static struct usb_serial_driver ch341_device
= {
316 .owner
= THIS_MODULE
,
317 .name
= "ch341-uart",
319 .id_table
= id_table
,
320 .usb_driver
= &ch341_driver
,
321 .num_interrupt_in
= NUM_DONT_CARE
,
326 .set_termios
= ch341_set_termios
,
327 .attach
= ch341_attach
,
330 static int __init
ch341_init(void)
334 retval
= usb_serial_register(&ch341_device
);
337 retval
= usb_register(&ch341_driver
);
339 usb_serial_deregister(&ch341_device
);
343 static void __exit
ch341_exit(void)
345 usb_deregister(&ch341_driver
);
346 usb_serial_deregister(&ch341_device
);
349 module_init(ch341_init
);
350 module_exit(ch341_exit
);
351 MODULE_LICENSE("GPL");
353 module_param(debug
, bool, S_IRUGO
| S_IWUSR
);
354 MODULE_PARM_DESC(debug
, "Debug enabled or not");