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1/*
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>
5 *
6 * ch341.c implements a serial port driver for the Winchiphead CH341.
7 *
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.
12 *
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.
16 */
17
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>
26
27#define DEFAULT_BAUD_RATE 9600
28#define DEFAULT_TIMEOUT 1000
29
30/* flags for IO-Bits */
31#define CH341_BIT_RTS (1 << 6)
32#define CH341_BIT_DTR (1 << 5)
33
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 */
42
43/* second interrupt byte */
44#define CH341_MULT_STAT 0x04 /* multiple status since last interrupt event */
45
46/* status returned in third interrupt answer byte, inverted in data
47 from irq */
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 */
53
54/*******************************/
55/* baudrate calculation factor */
56/*******************************/
57#define CH341_BAUDBASE_FACTOR 1532620800
58#define CH341_BAUDBASE_DIVMAX 3
59
60/* Break support - the information used to implement this was gleaned from
61 * the Net/FreeBSD uchcom.c driver by Takanori Watanabe. Domo arigato.
62 */
63
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
70
71
72static const struct usb_device_id id_table[] = {
73 { USB_DEVICE(0x4348, 0x5523) },
74 { USB_DEVICE(0x1a86, 0x7523) },
75 { USB_DEVICE(0x1a86, 0x5523) },
76 { },
77};
78MODULE_DEVICE_TABLE(usb, id_table);
79
80struct 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 */
85};
86
87static void ch341_set_termios(struct tty_struct *tty,
88 struct usb_serial_port *port,
89 struct ktermios *old_termios);
90
91static int ch341_control_out(struct usb_device *dev, u8 request,
92 u16 value, u16 index)
93{
94 int r;
95
96 dev_dbg(&dev->dev, "ch341_control_out(%02x,%02x,%04x,%04x)\n",
97 USB_DIR_OUT|0x40, (int)request, (int)value, (int)index);
98
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);
102
103 return r;
104}
105
106static int ch341_control_in(struct usb_device *dev,
107 u8 request, u16 value, u16 index,
108 char *buf, unsigned bufsize)
109{
110 int r;
111
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,
114 (int)bufsize);
115
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);
119 return r;
120}
121
122static int ch341_set_baudrate(struct usb_device *dev,
123 struct ch341_private *priv)
124{
125 short a, b;
126 int r;
127 unsigned long factor;
128 short divisor;
129
130 if (!priv->baud_rate)
131 return -EINVAL;
132 factor = (CH341_BAUDBASE_FACTOR / priv->baud_rate);
133 divisor = CH341_BAUDBASE_DIVMAX;
134
135 while ((factor > 0xfff0) && divisor) {
136 factor >>= 3;
137 divisor--;
138 }
139
140 if (factor > 0xfff0)
141 return -EINVAL;
142
143 factor = 0x10000 - factor;
144 a = (factor & 0xff00) | divisor;
145 b = factor & 0xff;
146
147 r = ch341_control_out(dev, 0x9a, 0x1312, a);
148 if (!r)
149 r = ch341_control_out(dev, 0x9a, 0x0f2c, b);
150
151 return r;
152}
153
154static int ch341_set_handshake(struct usb_device *dev, u8 control)
155{
156 return ch341_control_out(dev, 0xa4, ~control, 0);
157}
158
159static int ch341_get_status(struct usb_device *dev, struct ch341_private *priv)
160{
161 char *buffer;
162 int r;
163 const unsigned size = 8;
164 unsigned long flags;
165
166 buffer = kmalloc(size, GFP_KERNEL);
167 if (!buffer)
168 return -ENOMEM;
169
170 r = ch341_control_in(dev, 0x95, 0x0706, 0, buffer, size);
171 if (r < 0)
172 goto out;
173
174 /* setup the private status if available */
175 if (r == 2) {
176 r = 0;
177 spin_lock_irqsave(&priv->lock, flags);
178 priv->line_status = (~(*buffer)) & CH341_BITS_MODEM_STAT;
179 spin_unlock_irqrestore(&priv->lock, flags);
180 } else
181 r = -EPROTO;
182
183out: kfree(buffer);
184 return r;
185}
186
187/* -------------------------------------------------------------------------- */
188
189static int ch341_configure(struct usb_device *dev, struct ch341_private *priv)
190{
191 char *buffer;
192 int r;
193 const unsigned size = 8;
194
195 buffer = kmalloc(size, GFP_KERNEL);
196 if (!buffer)
197 return -ENOMEM;
198
199 /* expect two bytes 0x27 0x00 */
200 r = ch341_control_in(dev, 0x5f, 0, 0, buffer, size);
201 if (r < 0)
202 goto out;
203
204 r = ch341_control_out(dev, 0xa1, 0, 0);
205 if (r < 0)
206 goto out;
207
208 r = ch341_set_baudrate(dev, priv);
209 if (r < 0)
210 goto out;
211
212 /* expect two bytes 0x56 0x00 */
213 r = ch341_control_in(dev, 0x95, 0x2518, 0, buffer, size);
214 if (r < 0)
215 goto out;
216
217 r = ch341_control_out(dev, 0x9a, 0x2518, 0x0050);
218 if (r < 0)
219 goto out;
220
221 /* expect 0xff 0xee */
222 r = ch341_get_status(dev, priv);
223 if (r < 0)
224 goto out;
225
226 r = ch341_control_out(dev, 0xa1, 0x501f, 0xd90a);
227 if (r < 0)
228 goto out;
229
230 r = ch341_set_baudrate(dev, priv);
231 if (r < 0)
232 goto out;
233
234 r = ch341_set_handshake(dev, priv->line_control);
235 if (r < 0)
236 goto out;
237
238 /* expect 0x9f 0xee */
239 r = ch341_get_status(dev, priv);
240
241out: kfree(buffer);
242 return r;
243}
244
245static int ch341_port_probe(struct usb_serial_port *port)
246{
247 struct ch341_private *priv;
248 int r;
249
250 priv = kzalloc(sizeof(struct ch341_private), GFP_KERNEL);
251 if (!priv)
252 return -ENOMEM;
253
254 spin_lock_init(&priv->lock);
255 priv->baud_rate = DEFAULT_BAUD_RATE;
256 priv->line_control = CH341_BIT_RTS | CH341_BIT_DTR;
257
258 r = ch341_configure(port->serial->dev, priv);
259 if (r < 0)
260 goto error;
261
262 usb_set_serial_port_data(port, priv);
263 return 0;
264
265error: kfree(priv);
266 return r;
267}
268
269static int ch341_port_remove(struct usb_serial_port *port)
270{
271 struct ch341_private *priv;
272
273 priv = usb_get_serial_port_data(port);
274 kfree(priv);
275
276 return 0;
277}
278
279static int ch341_carrier_raised(struct usb_serial_port *port)
280{
281 struct ch341_private *priv = usb_get_serial_port_data(port);
282 if (priv->line_status & CH341_BIT_DCD)
283 return 1;
284 return 0;
285}
286
287static void ch341_dtr_rts(struct usb_serial_port *port, int on)
288{
289 struct ch341_private *priv = usb_get_serial_port_data(port);
290 unsigned long flags;
291
292 /* drop DTR and RTS */
293 spin_lock_irqsave(&priv->lock, flags);
294 if (on)
295 priv->line_control |= CH341_BIT_RTS | CH341_BIT_DTR;
296 else
297 priv->line_control &= ~(CH341_BIT_RTS | CH341_BIT_DTR);
298 spin_unlock_irqrestore(&priv->lock, flags);
299 ch341_set_handshake(port->serial->dev, priv->line_control);
300}
301
302static void ch341_close(struct usb_serial_port *port)
303{
304 usb_serial_generic_close(port);
305 usb_kill_urb(port->interrupt_in_urb);
306}
307
308
309/* open this device, set default parameters */
310static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port)
311{
312 struct usb_serial *serial = port->serial;
313 struct ch341_private *priv = usb_get_serial_port_data(port);
314 int r;
315
316 r = ch341_configure(serial->dev, priv);
317 if (r)
318 goto out;
319
320 if (tty)
321 ch341_set_termios(tty, port, NULL);
322
323 dev_dbg(&port->dev, "%s - submitting interrupt urb\n", __func__);
324 r = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
325 if (r) {
326 dev_err(&port->dev, "%s - failed to submit interrupt urb: %d\n",
327 __func__, r);
328 goto out;
329 }
330
331 r = usb_serial_generic_open(tty, port);
332
333out: return r;
334}
335
336/* Old_termios contains the original termios settings and
337 * tty->termios contains the new setting to be used.
338 */
339static void ch341_set_termios(struct tty_struct *tty,
340 struct usb_serial_port *port, struct ktermios *old_termios)
341{
342 struct ch341_private *priv = usb_get_serial_port_data(port);
343 unsigned baud_rate;
344 unsigned long flags;
345
346 baud_rate = tty_get_baud_rate(tty);
347
348 priv->baud_rate = baud_rate;
349
350 if (baud_rate) {
351 spin_lock_irqsave(&priv->lock, flags);
352 priv->line_control |= (CH341_BIT_DTR | CH341_BIT_RTS);
353 spin_unlock_irqrestore(&priv->lock, flags);
354 ch341_set_baudrate(port->serial->dev, priv);
355 } else {
356 spin_lock_irqsave(&priv->lock, flags);
357 priv->line_control &= ~(CH341_BIT_DTR | CH341_BIT_RTS);
358 spin_unlock_irqrestore(&priv->lock, flags);
359 }
360
361 ch341_set_handshake(port->serial->dev, priv->line_control);
362
363 /* Unimplemented:
364 * (cflag & CSIZE) : data bits [5, 8]
365 * (cflag & PARENB) : parity {NONE, EVEN, ODD}
366 * (cflag & CSTOPB) : stop bits [1, 2]
367 */
368}
369
370static void ch341_break_ctl(struct tty_struct *tty, int break_state)
371{
372 const uint16_t ch341_break_reg =
373 ((uint16_t) CH341_REG_BREAK2 << 8) | CH341_REG_BREAK1;
374 struct usb_serial_port *port = tty->driver_data;
375 int r;
376 uint16_t reg_contents;
377 uint8_t *break_reg;
378
379 break_reg = kmalloc(2, GFP_KERNEL);
380 if (!break_reg)
381 return;
382
383 r = ch341_control_in(port->serial->dev, CH341_REQ_READ_REG,
384 ch341_break_reg, 0, break_reg, 2);
385 if (r < 0) {
386 dev_err(&port->dev, "%s - USB control read error (%d)\n",
387 __func__, r);
388 goto out;
389 }
390 dev_dbg(&port->dev, "%s - initial ch341 break register contents - reg1: %x, reg2: %x\n",
391 __func__, break_reg[0], break_reg[1]);
392 if (break_state != 0) {
393 dev_dbg(&port->dev, "%s - Enter break state requested\n", __func__);
394 break_reg[0] &= ~CH341_NBREAK_BITS_REG1;
395 break_reg[1] &= ~CH341_NBREAK_BITS_REG2;
396 } else {
397 dev_dbg(&port->dev, "%s - Leave break state requested\n", __func__);
398 break_reg[0] |= CH341_NBREAK_BITS_REG1;
399 break_reg[1] |= CH341_NBREAK_BITS_REG2;
400 }
401 dev_dbg(&port->dev, "%s - New ch341 break register contents - reg1: %x, reg2: %x\n",
402 __func__, break_reg[0], break_reg[1]);
403 reg_contents = get_unaligned_le16(break_reg);
404 r = ch341_control_out(port->serial->dev, CH341_REQ_WRITE_REG,
405 ch341_break_reg, reg_contents);
406 if (r < 0)
407 dev_err(&port->dev, "%s - USB control write error (%d)\n",
408 __func__, r);
409out:
410 kfree(break_reg);
411}
412
413static int ch341_tiocmset(struct tty_struct *tty,
414 unsigned int set, unsigned int clear)
415{
416 struct usb_serial_port *port = tty->driver_data;
417 struct ch341_private *priv = usb_get_serial_port_data(port);
418 unsigned long flags;
419 u8 control;
420
421 spin_lock_irqsave(&priv->lock, flags);
422 if (set & TIOCM_RTS)
423 priv->line_control |= CH341_BIT_RTS;
424 if (set & TIOCM_DTR)
425 priv->line_control |= CH341_BIT_DTR;
426 if (clear & TIOCM_RTS)
427 priv->line_control &= ~CH341_BIT_RTS;
428 if (clear & TIOCM_DTR)
429 priv->line_control &= ~CH341_BIT_DTR;
430 control = priv->line_control;
431 spin_unlock_irqrestore(&priv->lock, flags);
432
433 return ch341_set_handshake(port->serial->dev, control);
434}
435
436static void ch341_update_line_status(struct usb_serial_port *port,
437 unsigned char *data, size_t len)
438{
439 struct ch341_private *priv = usb_get_serial_port_data(port);
440 struct tty_struct *tty;
441 unsigned long flags;
442 u8 status;
443 u8 delta;
444
445 if (len < 4)
446 return;
447
448 status = ~data[2] & CH341_BITS_MODEM_STAT;
449
450 spin_lock_irqsave(&priv->lock, flags);
451 delta = status ^ priv->line_status;
452 priv->line_status = status;
453 spin_unlock_irqrestore(&priv->lock, flags);
454
455 if (data[1] & CH341_MULT_STAT)
456 dev_dbg(&port->dev, "%s - multiple status change\n", __func__);
457
458 if (!delta)
459 return;
460
461 if (delta & CH341_BIT_CTS)
462 port->icount.cts++;
463 if (delta & CH341_BIT_DSR)
464 port->icount.dsr++;
465 if (delta & CH341_BIT_RI)
466 port->icount.rng++;
467 if (delta & CH341_BIT_DCD) {
468 port->icount.dcd++;
469 tty = tty_port_tty_get(&port->port);
470 if (tty) {
471 usb_serial_handle_dcd_change(port, tty,
472 status & CH341_BIT_DCD);
473 tty_kref_put(tty);
474 }
475 }
476
477 wake_up_interruptible(&port->port.delta_msr_wait);
478}
479
480static void ch341_read_int_callback(struct urb *urb)
481{
482 struct usb_serial_port *port = urb->context;
483 unsigned char *data = urb->transfer_buffer;
484 unsigned int len = urb->actual_length;
485 int status;
486
487 switch (urb->status) {
488 case 0:
489 /* success */
490 break;
491 case -ECONNRESET:
492 case -ENOENT:
493 case -ESHUTDOWN:
494 /* this urb is terminated, clean up */
495 dev_dbg(&urb->dev->dev, "%s - urb shutting down: %d\n",
496 __func__, urb->status);
497 return;
498 default:
499 dev_dbg(&urb->dev->dev, "%s - nonzero urb status: %d\n",
500 __func__, urb->status);
501 goto exit;
502 }
503
504 usb_serial_debug_data(&port->dev, __func__, len, data);
505 ch341_update_line_status(port, data, len);
506exit:
507 status = usb_submit_urb(urb, GFP_ATOMIC);
508 if (status) {
509 dev_err(&urb->dev->dev, "%s - usb_submit_urb failed: %d\n",
510 __func__, status);
511 }
512}
513
514static int ch341_tiocmget(struct tty_struct *tty)
515{
516 struct usb_serial_port *port = tty->driver_data;
517 struct ch341_private *priv = usb_get_serial_port_data(port);
518 unsigned long flags;
519 u8 mcr;
520 u8 status;
521 unsigned int result;
522
523 spin_lock_irqsave(&priv->lock, flags);
524 mcr = priv->line_control;
525 status = priv->line_status;
526 spin_unlock_irqrestore(&priv->lock, flags);
527
528 result = ((mcr & CH341_BIT_DTR) ? TIOCM_DTR : 0)
529 | ((mcr & CH341_BIT_RTS) ? TIOCM_RTS : 0)
530 | ((status & CH341_BIT_CTS) ? TIOCM_CTS : 0)
531 | ((status & CH341_BIT_DSR) ? TIOCM_DSR : 0)
532 | ((status & CH341_BIT_RI) ? TIOCM_RI : 0)
533 | ((status & CH341_BIT_DCD) ? TIOCM_CD : 0);
534
535 dev_dbg(&port->dev, "%s - result = %x\n", __func__, result);
536
537 return result;
538}
539
540static int ch341_reset_resume(struct usb_serial *serial)
541{
542 struct ch341_private *priv;
543
544 priv = usb_get_serial_port_data(serial->port[0]);
545
546 /* reconfigure ch341 serial port after bus-reset */
547 ch341_configure(serial->dev, priv);
548
549 return 0;
550}
551
552static struct usb_serial_driver ch341_device = {
553 .driver = {
554 .owner = THIS_MODULE,
555 .name = "ch341-uart",
556 },
557 .id_table = id_table,
558 .num_ports = 1,
559 .open = ch341_open,
560 .dtr_rts = ch341_dtr_rts,
561 .carrier_raised = ch341_carrier_raised,
562 .close = ch341_close,
563 .set_termios = ch341_set_termios,
564 .break_ctl = ch341_break_ctl,
565 .tiocmget = ch341_tiocmget,
566 .tiocmset = ch341_tiocmset,
567 .tiocmiwait = usb_serial_generic_tiocmiwait,
568 .read_int_callback = ch341_read_int_callback,
569 .port_probe = ch341_port_probe,
570 .port_remove = ch341_port_remove,
571 .reset_resume = ch341_reset_resume,
572};
573
574static struct usb_serial_driver * const serial_drivers[] = {
575 &ch341_device, NULL
576};
577
578module_usb_serial_driver(serial_drivers, id_table);
579
580MODULE_LICENSE("GPL");
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright 2007, Frank A Kingswood <frank@kingswood-consulting.co.uk>
4 * Copyright 2007, Werner Cornelius <werner@cornelius-consult.de>
5 * Copyright 2009, Boris Hajduk <boris@hajduk.org>
6 *
7 * ch341.c implements a serial port driver for the Winchiphead CH341.
8 *
9 * The CH341 device can be used to implement an RS232 asynchronous
10 * serial port, an IEEE-1284 parallel printer port or a memory-like
11 * interface. In all cases the CH341 supports an I2C interface as well.
12 * This driver only supports the asynchronous serial interface.
13 */
14
15#include <linux/kernel.h>
16#include <linux/tty.h>
17#include <linux/module.h>
18#include <linux/slab.h>
19#include <linux/usb.h>
20#include <linux/usb/serial.h>
21#include <linux/serial.h>
22#include <asm/unaligned.h>
23
24#define DEFAULT_BAUD_RATE 9600
25#define DEFAULT_TIMEOUT 1000
26
27/* flags for IO-Bits */
28#define CH341_BIT_RTS (1 << 6)
29#define CH341_BIT_DTR (1 << 5)
30
31/******************************/
32/* interrupt pipe definitions */
33/******************************/
34/* always 4 interrupt bytes */
35/* first irq byte normally 0x08 */
36/* second irq byte base 0x7d + below */
37/* third irq byte base 0x94 + below */
38/* fourth irq byte normally 0xee */
39
40/* second interrupt byte */
41#define CH341_MULT_STAT 0x04 /* multiple status since last interrupt event */
42
43/* status returned in third interrupt answer byte, inverted in data
44 from irq */
45#define CH341_BIT_CTS 0x01
46#define CH341_BIT_DSR 0x02
47#define CH341_BIT_RI 0x04
48#define CH341_BIT_DCD 0x08
49#define CH341_BITS_MODEM_STAT 0x0f /* all bits */
50
51/*******************************/
52/* baudrate calculation factor */
53/*******************************/
54#define CH341_BAUDBASE_FACTOR 1532620800
55#define CH341_BAUDBASE_DIVMAX 3
56
57/* Break support - the information used to implement this was gleaned from
58 * the Net/FreeBSD uchcom.c driver by Takanori Watanabe. Domo arigato.
59 */
60
61#define CH341_REQ_READ_VERSION 0x5F
62#define CH341_REQ_WRITE_REG 0x9A
63#define CH341_REQ_READ_REG 0x95
64#define CH341_REQ_SERIAL_INIT 0xA1
65#define CH341_REQ_MODEM_CTRL 0xA4
66
67#define CH341_REG_BREAK 0x05
68#define CH341_REG_LCR 0x18
69#define CH341_NBREAK_BITS 0x01
70
71#define CH341_LCR_ENABLE_RX 0x80
72#define CH341_LCR_ENABLE_TX 0x40
73#define CH341_LCR_MARK_SPACE 0x20
74#define CH341_LCR_PAR_EVEN 0x10
75#define CH341_LCR_ENABLE_PAR 0x08
76#define CH341_LCR_STOP_BITS_2 0x04
77#define CH341_LCR_CS8 0x03
78#define CH341_LCR_CS7 0x02
79#define CH341_LCR_CS6 0x01
80#define CH341_LCR_CS5 0x00
81
82static const struct usb_device_id id_table[] = {
83 { USB_DEVICE(0x4348, 0x5523) },
84 { USB_DEVICE(0x1a86, 0x7523) },
85 { USB_DEVICE(0x1a86, 0x5523) },
86 { },
87};
88MODULE_DEVICE_TABLE(usb, id_table);
89
90struct ch341_private {
91 spinlock_t lock; /* access lock */
92 unsigned baud_rate; /* set baud rate */
93 u8 mcr;
94 u8 msr;
95 u8 lcr;
96};
97
98static void ch341_set_termios(struct tty_struct *tty,
99 struct usb_serial_port *port,
100 struct ktermios *old_termios);
101
102static int ch341_control_out(struct usb_device *dev, u8 request,
103 u16 value, u16 index)
104{
105 int r;
106
107 dev_dbg(&dev->dev, "%s - (%02x,%04x,%04x)\n", __func__,
108 request, value, index);
109
110 r = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), request,
111 USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT,
112 value, index, NULL, 0, DEFAULT_TIMEOUT);
113 if (r < 0)
114 dev_err(&dev->dev, "failed to send control message: %d\n", r);
115
116 return r;
117}
118
119static int ch341_control_in(struct usb_device *dev,
120 u8 request, u16 value, u16 index,
121 char *buf, unsigned bufsize)
122{
123 int r;
124
125 dev_dbg(&dev->dev, "%s - (%02x,%04x,%04x,%u)\n", __func__,
126 request, value, index, bufsize);
127
128 r = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), request,
129 USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
130 value, index, buf, bufsize, DEFAULT_TIMEOUT);
131 if (r < bufsize) {
132 if (r >= 0) {
133 dev_err(&dev->dev,
134 "short control message received (%d < %u)\n",
135 r, bufsize);
136 r = -EIO;
137 }
138
139 dev_err(&dev->dev, "failed to receive control message: %d\n",
140 r);
141 return r;
142 }
143
144 return 0;
145}
146
147static int ch341_set_baudrate_lcr(struct usb_device *dev,
148 struct ch341_private *priv, u8 lcr)
149{
150 short a;
151 int r;
152 unsigned long factor;
153 short divisor;
154
155 if (!priv->baud_rate)
156 return -EINVAL;
157 factor = (CH341_BAUDBASE_FACTOR / priv->baud_rate);
158 divisor = CH341_BAUDBASE_DIVMAX;
159
160 while ((factor > 0xfff0) && divisor) {
161 factor >>= 3;
162 divisor--;
163 }
164
165 if (factor > 0xfff0)
166 return -EINVAL;
167
168 factor = 0x10000 - factor;
169 a = (factor & 0xff00) | divisor;
170
171 /*
172 * CH341A buffers data until a full endpoint-size packet (32 bytes)
173 * has been received unless bit 7 is set.
174 */
175 a |= BIT(7);
176
177 r = ch341_control_out(dev, CH341_REQ_WRITE_REG, 0x1312, a);
178 if (r)
179 return r;
180
181 r = ch341_control_out(dev, CH341_REQ_WRITE_REG, 0x2518, lcr);
182 if (r)
183 return r;
184
185 return r;
186}
187
188static int ch341_set_handshake(struct usb_device *dev, u8 control)
189{
190 return ch341_control_out(dev, CH341_REQ_MODEM_CTRL, ~control, 0);
191}
192
193static int ch341_get_status(struct usb_device *dev, struct ch341_private *priv)
194{
195 const unsigned int size = 2;
196 char *buffer;
197 int r;
198 unsigned long flags;
199
200 buffer = kmalloc(size, GFP_KERNEL);
201 if (!buffer)
202 return -ENOMEM;
203
204 r = ch341_control_in(dev, CH341_REQ_READ_REG, 0x0706, 0, buffer, size);
205 if (r < 0)
206 goto out;
207
208 spin_lock_irqsave(&priv->lock, flags);
209 priv->msr = (~(*buffer)) & CH341_BITS_MODEM_STAT;
210 spin_unlock_irqrestore(&priv->lock, flags);
211
212out: kfree(buffer);
213 return r;
214}
215
216/* -------------------------------------------------------------------------- */
217
218static int ch341_configure(struct usb_device *dev, struct ch341_private *priv)
219{
220 const unsigned int size = 2;
221 char *buffer;
222 int r;
223
224 buffer = kmalloc(size, GFP_KERNEL);
225 if (!buffer)
226 return -ENOMEM;
227
228 /* expect two bytes 0x27 0x00 */
229 r = ch341_control_in(dev, CH341_REQ_READ_VERSION, 0, 0, buffer, size);
230 if (r < 0)
231 goto out;
232 dev_dbg(&dev->dev, "Chip version: 0x%02x\n", buffer[0]);
233
234 r = ch341_control_out(dev, CH341_REQ_SERIAL_INIT, 0, 0);
235 if (r < 0)
236 goto out;
237
238 r = ch341_set_baudrate_lcr(dev, priv, priv->lcr);
239 if (r < 0)
240 goto out;
241
242 r = ch341_set_handshake(dev, priv->mcr);
243
244out: kfree(buffer);
245 return r;
246}
247
248static int ch341_port_probe(struct usb_serial_port *port)
249{
250 struct ch341_private *priv;
251 int r;
252
253 priv = kzalloc(sizeof(struct ch341_private), GFP_KERNEL);
254 if (!priv)
255 return -ENOMEM;
256
257 spin_lock_init(&priv->lock);
258 priv->baud_rate = DEFAULT_BAUD_RATE;
259 /*
260 * Some CH340 devices appear unable to change the initial LCR
261 * settings, so set a sane 8N1 default.
262 */
263 priv->lcr = CH341_LCR_ENABLE_RX | CH341_LCR_ENABLE_TX | CH341_LCR_CS8;
264
265 r = ch341_configure(port->serial->dev, priv);
266 if (r < 0)
267 goto error;
268
269 usb_set_serial_port_data(port, priv);
270 return 0;
271
272error: kfree(priv);
273 return r;
274}
275
276static int ch341_port_remove(struct usb_serial_port *port)
277{
278 struct ch341_private *priv;
279
280 priv = usb_get_serial_port_data(port);
281 kfree(priv);
282
283 return 0;
284}
285
286static int ch341_carrier_raised(struct usb_serial_port *port)
287{
288 struct ch341_private *priv = usb_get_serial_port_data(port);
289 if (priv->msr & CH341_BIT_DCD)
290 return 1;
291 return 0;
292}
293
294static void ch341_dtr_rts(struct usb_serial_port *port, int on)
295{
296 struct ch341_private *priv = usb_get_serial_port_data(port);
297 unsigned long flags;
298
299 /* drop DTR and RTS */
300 spin_lock_irqsave(&priv->lock, flags);
301 if (on)
302 priv->mcr |= CH341_BIT_RTS | CH341_BIT_DTR;
303 else
304 priv->mcr &= ~(CH341_BIT_RTS | CH341_BIT_DTR);
305 spin_unlock_irqrestore(&priv->lock, flags);
306 ch341_set_handshake(port->serial->dev, priv->mcr);
307}
308
309static void ch341_close(struct usb_serial_port *port)
310{
311 usb_serial_generic_close(port);
312 usb_kill_urb(port->interrupt_in_urb);
313}
314
315
316/* open this device, set default parameters */
317static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port)
318{
319 struct ch341_private *priv = usb_get_serial_port_data(port);
320 int r;
321
322 if (tty)
323 ch341_set_termios(tty, port, NULL);
324
325 dev_dbg(&port->dev, "%s - submitting interrupt urb\n", __func__);
326 r = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
327 if (r) {
328 dev_err(&port->dev, "%s - failed to submit interrupt urb: %d\n",
329 __func__, r);
330 return r;
331 }
332
333 r = ch341_get_status(port->serial->dev, priv);
334 if (r < 0) {
335 dev_err(&port->dev, "failed to read modem status: %d\n", r);
336 goto err_kill_interrupt_urb;
337 }
338
339 r = usb_serial_generic_open(tty, port);
340 if (r)
341 goto err_kill_interrupt_urb;
342
343 return 0;
344
345err_kill_interrupt_urb:
346 usb_kill_urb(port->interrupt_in_urb);
347
348 return r;
349}
350
351/* Old_termios contains the original termios settings and
352 * tty->termios contains the new setting to be used.
353 */
354static void ch341_set_termios(struct tty_struct *tty,
355 struct usb_serial_port *port, struct ktermios *old_termios)
356{
357 struct ch341_private *priv = usb_get_serial_port_data(port);
358 unsigned baud_rate;
359 unsigned long flags;
360 u8 lcr;
361 int r;
362
363 /* redundant changes may cause the chip to lose bytes */
364 if (old_termios && !tty_termios_hw_change(&tty->termios, old_termios))
365 return;
366
367 baud_rate = tty_get_baud_rate(tty);
368
369 lcr = CH341_LCR_ENABLE_RX | CH341_LCR_ENABLE_TX;
370
371 switch (C_CSIZE(tty)) {
372 case CS5:
373 lcr |= CH341_LCR_CS5;
374 break;
375 case CS6:
376 lcr |= CH341_LCR_CS6;
377 break;
378 case CS7:
379 lcr |= CH341_LCR_CS7;
380 break;
381 case CS8:
382 lcr |= CH341_LCR_CS8;
383 break;
384 }
385
386 if (C_PARENB(tty)) {
387 lcr |= CH341_LCR_ENABLE_PAR;
388 if (C_PARODD(tty) == 0)
389 lcr |= CH341_LCR_PAR_EVEN;
390 if (C_CMSPAR(tty))
391 lcr |= CH341_LCR_MARK_SPACE;
392 }
393
394 if (C_CSTOPB(tty))
395 lcr |= CH341_LCR_STOP_BITS_2;
396
397 if (baud_rate) {
398 priv->baud_rate = baud_rate;
399
400 r = ch341_set_baudrate_lcr(port->serial->dev, priv, lcr);
401 if (r < 0 && old_termios) {
402 priv->baud_rate = tty_termios_baud_rate(old_termios);
403 tty_termios_copy_hw(&tty->termios, old_termios);
404 } else if (r == 0) {
405 priv->lcr = lcr;
406 }
407 }
408
409 spin_lock_irqsave(&priv->lock, flags);
410 if (C_BAUD(tty) == B0)
411 priv->mcr &= ~(CH341_BIT_DTR | CH341_BIT_RTS);
412 else if (old_termios && (old_termios->c_cflag & CBAUD) == B0)
413 priv->mcr |= (CH341_BIT_DTR | CH341_BIT_RTS);
414 spin_unlock_irqrestore(&priv->lock, flags);
415
416 ch341_set_handshake(port->serial->dev, priv->mcr);
417}
418
419static void ch341_break_ctl(struct tty_struct *tty, int break_state)
420{
421 const uint16_t ch341_break_reg =
422 ((uint16_t) CH341_REG_LCR << 8) | CH341_REG_BREAK;
423 struct usb_serial_port *port = tty->driver_data;
424 int r;
425 uint16_t reg_contents;
426 uint8_t *break_reg;
427
428 break_reg = kmalloc(2, GFP_KERNEL);
429 if (!break_reg)
430 return;
431
432 r = ch341_control_in(port->serial->dev, CH341_REQ_READ_REG,
433 ch341_break_reg, 0, break_reg, 2);
434 if (r < 0) {
435 dev_err(&port->dev, "%s - USB control read error (%d)\n",
436 __func__, r);
437 goto out;
438 }
439 dev_dbg(&port->dev, "%s - initial ch341 break register contents - reg1: %x, reg2: %x\n",
440 __func__, break_reg[0], break_reg[1]);
441 if (break_state != 0) {
442 dev_dbg(&port->dev, "%s - Enter break state requested\n", __func__);
443 break_reg[0] &= ~CH341_NBREAK_BITS;
444 break_reg[1] &= ~CH341_LCR_ENABLE_TX;
445 } else {
446 dev_dbg(&port->dev, "%s - Leave break state requested\n", __func__);
447 break_reg[0] |= CH341_NBREAK_BITS;
448 break_reg[1] |= CH341_LCR_ENABLE_TX;
449 }
450 dev_dbg(&port->dev, "%s - New ch341 break register contents - reg1: %x, reg2: %x\n",
451 __func__, break_reg[0], break_reg[1]);
452 reg_contents = get_unaligned_le16(break_reg);
453 r = ch341_control_out(port->serial->dev, CH341_REQ_WRITE_REG,
454 ch341_break_reg, reg_contents);
455 if (r < 0)
456 dev_err(&port->dev, "%s - USB control write error (%d)\n",
457 __func__, r);
458out:
459 kfree(break_reg);
460}
461
462static int ch341_tiocmset(struct tty_struct *tty,
463 unsigned int set, unsigned int clear)
464{
465 struct usb_serial_port *port = tty->driver_data;
466 struct ch341_private *priv = usb_get_serial_port_data(port);
467 unsigned long flags;
468 u8 control;
469
470 spin_lock_irqsave(&priv->lock, flags);
471 if (set & TIOCM_RTS)
472 priv->mcr |= CH341_BIT_RTS;
473 if (set & TIOCM_DTR)
474 priv->mcr |= CH341_BIT_DTR;
475 if (clear & TIOCM_RTS)
476 priv->mcr &= ~CH341_BIT_RTS;
477 if (clear & TIOCM_DTR)
478 priv->mcr &= ~CH341_BIT_DTR;
479 control = priv->mcr;
480 spin_unlock_irqrestore(&priv->lock, flags);
481
482 return ch341_set_handshake(port->serial->dev, control);
483}
484
485static void ch341_update_status(struct usb_serial_port *port,
486 unsigned char *data, size_t len)
487{
488 struct ch341_private *priv = usb_get_serial_port_data(port);
489 struct tty_struct *tty;
490 unsigned long flags;
491 u8 status;
492 u8 delta;
493
494 if (len < 4)
495 return;
496
497 status = ~data[2] & CH341_BITS_MODEM_STAT;
498
499 spin_lock_irqsave(&priv->lock, flags);
500 delta = status ^ priv->msr;
501 priv->msr = status;
502 spin_unlock_irqrestore(&priv->lock, flags);
503
504 if (data[1] & CH341_MULT_STAT)
505 dev_dbg(&port->dev, "%s - multiple status change\n", __func__);
506
507 if (!delta)
508 return;
509
510 if (delta & CH341_BIT_CTS)
511 port->icount.cts++;
512 if (delta & CH341_BIT_DSR)
513 port->icount.dsr++;
514 if (delta & CH341_BIT_RI)
515 port->icount.rng++;
516 if (delta & CH341_BIT_DCD) {
517 port->icount.dcd++;
518 tty = tty_port_tty_get(&port->port);
519 if (tty) {
520 usb_serial_handle_dcd_change(port, tty,
521 status & CH341_BIT_DCD);
522 tty_kref_put(tty);
523 }
524 }
525
526 wake_up_interruptible(&port->port.delta_msr_wait);
527}
528
529static void ch341_read_int_callback(struct urb *urb)
530{
531 struct usb_serial_port *port = urb->context;
532 unsigned char *data = urb->transfer_buffer;
533 unsigned int len = urb->actual_length;
534 int status;
535
536 switch (urb->status) {
537 case 0:
538 /* success */
539 break;
540 case -ECONNRESET:
541 case -ENOENT:
542 case -ESHUTDOWN:
543 /* this urb is terminated, clean up */
544 dev_dbg(&urb->dev->dev, "%s - urb shutting down: %d\n",
545 __func__, urb->status);
546 return;
547 default:
548 dev_dbg(&urb->dev->dev, "%s - nonzero urb status: %d\n",
549 __func__, urb->status);
550 goto exit;
551 }
552
553 usb_serial_debug_data(&port->dev, __func__, len, data);
554 ch341_update_status(port, data, len);
555exit:
556 status = usb_submit_urb(urb, GFP_ATOMIC);
557 if (status) {
558 dev_err(&urb->dev->dev, "%s - usb_submit_urb failed: %d\n",
559 __func__, status);
560 }
561}
562
563static int ch341_tiocmget(struct tty_struct *tty)
564{
565 struct usb_serial_port *port = tty->driver_data;
566 struct ch341_private *priv = usb_get_serial_port_data(port);
567 unsigned long flags;
568 u8 mcr;
569 u8 status;
570 unsigned int result;
571
572 spin_lock_irqsave(&priv->lock, flags);
573 mcr = priv->mcr;
574 status = priv->msr;
575 spin_unlock_irqrestore(&priv->lock, flags);
576
577 result = ((mcr & CH341_BIT_DTR) ? TIOCM_DTR : 0)
578 | ((mcr & CH341_BIT_RTS) ? TIOCM_RTS : 0)
579 | ((status & CH341_BIT_CTS) ? TIOCM_CTS : 0)
580 | ((status & CH341_BIT_DSR) ? TIOCM_DSR : 0)
581 | ((status & CH341_BIT_RI) ? TIOCM_RI : 0)
582 | ((status & CH341_BIT_DCD) ? TIOCM_CD : 0);
583
584 dev_dbg(&port->dev, "%s - result = %x\n", __func__, result);
585
586 return result;
587}
588
589static int ch341_reset_resume(struct usb_serial *serial)
590{
591 struct usb_serial_port *port = serial->port[0];
592 struct ch341_private *priv = usb_get_serial_port_data(port);
593 int ret;
594
595 /* reconfigure ch341 serial port after bus-reset */
596 ch341_configure(serial->dev, priv);
597
598 if (tty_port_initialized(&port->port)) {
599 ret = usb_submit_urb(port->interrupt_in_urb, GFP_NOIO);
600 if (ret) {
601 dev_err(&port->dev, "failed to submit interrupt urb: %d\n",
602 ret);
603 return ret;
604 }
605
606 ret = ch341_get_status(port->serial->dev, priv);
607 if (ret < 0) {
608 dev_err(&port->dev, "failed to read modem status: %d\n",
609 ret);
610 }
611 }
612
613 return usb_serial_generic_resume(serial);
614}
615
616static struct usb_serial_driver ch341_device = {
617 .driver = {
618 .owner = THIS_MODULE,
619 .name = "ch341-uart",
620 },
621 .id_table = id_table,
622 .num_ports = 1,
623 .open = ch341_open,
624 .dtr_rts = ch341_dtr_rts,
625 .carrier_raised = ch341_carrier_raised,
626 .close = ch341_close,
627 .set_termios = ch341_set_termios,
628 .break_ctl = ch341_break_ctl,
629 .tiocmget = ch341_tiocmget,
630 .tiocmset = ch341_tiocmset,
631 .tiocmiwait = usb_serial_generic_tiocmiwait,
632 .read_int_callback = ch341_read_int_callback,
633 .port_probe = ch341_port_probe,
634 .port_remove = ch341_port_remove,
635 .reset_resume = ch341_reset_resume,
636};
637
638static struct usb_serial_driver * const serial_drivers[] = {
639 &ch341_device, NULL
640};
641
642module_usb_serial_driver(serial_drivers, id_table);
643
644MODULE_LICENSE("GPL v2");