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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/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>
27
28#define DEFAULT_BAUD_RATE 9600
29#define DEFAULT_TIMEOUT 1000
30
31/* flags for IO-Bits */
32#define CH341_BIT_RTS (1 << 6)
33#define CH341_BIT_DTR (1 << 5)
34
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 */
43
44/* second interrupt byte */
45#define CH341_MULT_STAT 0x04 /* multiple status since last interrupt event */
46
47/* status returned in third interrupt answer byte, inverted in data
48 from irq */
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 */
54
55/*******************************/
56/* baudrate calculation factor */
57/*******************************/
58#define CH341_BAUDBASE_FACTOR 1532620800
59#define CH341_BAUDBASE_DIVMAX 3
60
61/* Break support - the information used to implement this was gleaned from
62 * the Net/FreeBSD uchcom.c driver by Takanori Watanabe. Domo arigato.
63 */
64
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
71
72
73static int debug;
74
75static const struct usb_device_id id_table[] = {
76 { USB_DEVICE(0x4348, 0x5523) },
77 { USB_DEVICE(0x1a86, 0x7523) },
78 { USB_DEVICE(0x1a86, 0x5523) },
79 { },
80};
81MODULE_DEVICE_TABLE(usb, id_table);
82
83struct ch341_private {
84 spinlock_t lock; /* access lock */
85 wait_queue_head_t delta_msr_wait; /* wait queue for modem status */
86 unsigned baud_rate; /* set baud rate */
87 u8 line_control; /* set line control value RTS/DTR */
88 u8 line_status; /* active status of modem control inputs */
89 u8 multi_status_change; /* status changed multiple since last call */
90};
91
92static int ch341_control_out(struct usb_device *dev, u8 request,
93 u16 value, u16 index)
94{
95 int r;
96 dbg("ch341_control_out(%02x,%02x,%04x,%04x)", USB_DIR_OUT|0x40,
97 (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 dbg("ch341_control_in(%02x,%02x,%04x,%04x,%p,%u)", USB_DIR_IN|0x40,
112 (int)request, (int)value, (int)index, buf, (int)bufsize);
113
114 r = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), request,
115 USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
116 value, index, buf, bufsize, DEFAULT_TIMEOUT);
117 return r;
118}
119
120static int ch341_set_baudrate(struct usb_device *dev,
121 struct ch341_private *priv)
122{
123 short a, b;
124 int r;
125 unsigned long factor;
126 short divisor;
127
128 dbg("ch341_set_baudrate(%d)", priv->baud_rate);
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 dbg("ch341_set_handshake(0x%02x)", control);
157 return ch341_control_out(dev, 0xa4, ~control, 0);
158}
159
160static int ch341_get_status(struct usb_device *dev, struct ch341_private *priv)
161{
162 char *buffer;
163 int r;
164 const unsigned size = 8;
165 unsigned long flags;
166
167 dbg("ch341_get_status()");
168
169 buffer = kmalloc(size, GFP_KERNEL);
170 if (!buffer)
171 return -ENOMEM;
172
173 r = ch341_control_in(dev, 0x95, 0x0706, 0, buffer, size);
174 if (r < 0)
175 goto out;
176
177 /* setup the private status if available */
178 if (r == 2) {
179 r = 0;
180 spin_lock_irqsave(&priv->lock, flags);
181 priv->line_status = (~(*buffer)) & CH341_BITS_MODEM_STAT;
182 priv->multi_status_change = 0;
183 spin_unlock_irqrestore(&priv->lock, flags);
184 } else
185 r = -EPROTO;
186
187out: kfree(buffer);
188 return r;
189}
190
191/* -------------------------------------------------------------------------- */
192
193static int ch341_configure(struct usb_device *dev, struct ch341_private *priv)
194{
195 char *buffer;
196 int r;
197 const unsigned size = 8;
198
199 dbg("ch341_configure()");
200
201 buffer = kmalloc(size, GFP_KERNEL);
202 if (!buffer)
203 return -ENOMEM;
204
205 /* expect two bytes 0x27 0x00 */
206 r = ch341_control_in(dev, 0x5f, 0, 0, buffer, size);
207 if (r < 0)
208 goto out;
209
210 r = ch341_control_out(dev, 0xa1, 0, 0);
211 if (r < 0)
212 goto out;
213
214 r = ch341_set_baudrate(dev, priv);
215 if (r < 0)
216 goto out;
217
218 /* expect two bytes 0x56 0x00 */
219 r = ch341_control_in(dev, 0x95, 0x2518, 0, buffer, size);
220 if (r < 0)
221 goto out;
222
223 r = ch341_control_out(dev, 0x9a, 0x2518, 0x0050);
224 if (r < 0)
225 goto out;
226
227 /* expect 0xff 0xee */
228 r = ch341_get_status(dev, priv);
229 if (r < 0)
230 goto out;
231
232 r = ch341_control_out(dev, 0xa1, 0x501f, 0xd90a);
233 if (r < 0)
234 goto out;
235
236 r = ch341_set_baudrate(dev, priv);
237 if (r < 0)
238 goto out;
239
240 r = ch341_set_handshake(dev, priv->line_control);
241 if (r < 0)
242 goto out;
243
244 /* expect 0x9f 0xee */
245 r = ch341_get_status(dev, priv);
246
247out: kfree(buffer);
248 return r;
249}
250
251/* allocate private data */
252static int ch341_attach(struct usb_serial *serial)
253{
254 struct ch341_private *priv;
255 int r;
256
257 dbg("ch341_attach()");
258
259 /* private data */
260 priv = kzalloc(sizeof(struct ch341_private), GFP_KERNEL);
261 if (!priv)
262 return -ENOMEM;
263
264 spin_lock_init(&priv->lock);
265 init_waitqueue_head(&priv->delta_msr_wait);
266 priv->baud_rate = DEFAULT_BAUD_RATE;
267 priv->line_control = CH341_BIT_RTS | CH341_BIT_DTR;
268
269 r = ch341_configure(serial->dev, priv);
270 if (r < 0)
271 goto error;
272
273 usb_set_serial_port_data(serial->port[0], priv);
274 return 0;
275
276error: kfree(priv);
277 return r;
278}
279
280static int ch341_carrier_raised(struct usb_serial_port *port)
281{
282 struct ch341_private *priv = usb_get_serial_port_data(port);
283 if (priv->line_status & CH341_BIT_DCD)
284 return 1;
285 return 0;
286}
287
288static void ch341_dtr_rts(struct usb_serial_port *port, int on)
289{
290 struct ch341_private *priv = usb_get_serial_port_data(port);
291 unsigned long flags;
292
293 dbg("%s - port %d", __func__, port->number);
294 /* drop DTR and RTS */
295 spin_lock_irqsave(&priv->lock, flags);
296 if (on)
297 priv->line_control |= CH341_BIT_RTS | CH341_BIT_DTR;
298 else
299 priv->line_control &= ~(CH341_BIT_RTS | CH341_BIT_DTR);
300 spin_unlock_irqrestore(&priv->lock, flags);
301 ch341_set_handshake(port->serial->dev, priv->line_control);
302 wake_up_interruptible(&priv->delta_msr_wait);
303}
304
305static void ch341_close(struct usb_serial_port *port)
306{
307 dbg("%s - port %d", __func__, port->number);
308
309 usb_serial_generic_close(port);
310 usb_kill_urb(port->interrupt_in_urb);
311}
312
313
314/* open this device, set default parameters */
315static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port)
316{
317 struct usb_serial *serial = port->serial;
318 struct ch341_private *priv = usb_get_serial_port_data(serial->port[0]);
319 int r;
320
321 dbg("ch341_open()");
322
323 priv->baud_rate = DEFAULT_BAUD_RATE;
324
325 r = ch341_configure(serial->dev, priv);
326 if (r)
327 goto out;
328
329 r = ch341_set_handshake(serial->dev, priv->line_control);
330 if (r)
331 goto out;
332
333 r = ch341_set_baudrate(serial->dev, priv);
334 if (r)
335 goto out;
336
337 dbg("%s - submitting interrupt urb", __func__);
338 port->interrupt_in_urb->dev = serial->dev;
339 r = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
340 if (r) {
341 dev_err(&port->dev, "%s - failed submitting interrupt urb,"
342 " error %d\n", __func__, r);
343 ch341_close(port);
344 return -EPROTO;
345 }
346
347 r = usb_serial_generic_open(tty, port);
348
349out: return r;
350}
351
352/* Old_termios contains the original termios settings and
353 * tty->termios contains the new setting to be used.
354 */
355static void ch341_set_termios(struct tty_struct *tty,
356 struct usb_serial_port *port, struct ktermios *old_termios)
357{
358 struct ch341_private *priv = usb_get_serial_port_data(port);
359 unsigned baud_rate;
360 unsigned long flags;
361
362 dbg("ch341_set_termios()");
363
364 baud_rate = tty_get_baud_rate(tty);
365
366 priv->baud_rate = baud_rate;
367
368 if (baud_rate) {
369 spin_lock_irqsave(&priv->lock, flags);
370 priv->line_control |= (CH341_BIT_DTR | CH341_BIT_RTS);
371 spin_unlock_irqrestore(&priv->lock, flags);
372 ch341_set_baudrate(port->serial->dev, priv);
373 } else {
374 spin_lock_irqsave(&priv->lock, flags);
375 priv->line_control &= ~(CH341_BIT_DTR | CH341_BIT_RTS);
376 spin_unlock_irqrestore(&priv->lock, flags);
377 }
378
379 ch341_set_handshake(port->serial->dev, priv->line_control);
380
381 /* Unimplemented:
382 * (cflag & CSIZE) : data bits [5, 8]
383 * (cflag & PARENB) : parity {NONE, EVEN, ODD}
384 * (cflag & CSTOPB) : stop bits [1, 2]
385 */
386}
387
388static void ch341_break_ctl(struct tty_struct *tty, int break_state)
389{
390 const uint16_t ch341_break_reg =
391 CH341_REG_BREAK1 | ((uint16_t) CH341_REG_BREAK2 << 8);
392 struct usb_serial_port *port = tty->driver_data;
393 int r;
394 uint16_t reg_contents;
395 uint8_t *break_reg;
396
397 dbg("%s()", __func__);
398
399 break_reg = kmalloc(2, GFP_KERNEL);
400 if (!break_reg) {
401 dev_err(&port->dev, "%s - kmalloc failed\n", __func__);
402 return;
403 }
404
405 r = ch341_control_in(port->serial->dev, CH341_REQ_READ_REG,
406 ch341_break_reg, 0, break_reg, 2);
407 if (r < 0) {
408 dev_err(&port->dev, "%s - USB control read error (%d)\n",
409 __func__, r);
410 goto out;
411 }
412 dbg("%s - initial ch341 break register contents - reg1: %x, reg2: %x",
413 __func__, break_reg[0], break_reg[1]);
414 if (break_state != 0) {
415 dbg("%s - Enter break state requested", __func__);
416 break_reg[0] &= ~CH341_NBREAK_BITS_REG1;
417 break_reg[1] &= ~CH341_NBREAK_BITS_REG2;
418 } else {
419 dbg("%s - Leave break state requested", __func__);
420 break_reg[0] |= CH341_NBREAK_BITS_REG1;
421 break_reg[1] |= CH341_NBREAK_BITS_REG2;
422 }
423 dbg("%s - New ch341 break register contents - reg1: %x, reg2: %x",
424 __func__, break_reg[0], break_reg[1]);
425 reg_contents = get_unaligned_le16(break_reg);
426 r = ch341_control_out(port->serial->dev, CH341_REQ_WRITE_REG,
427 ch341_break_reg, reg_contents);
428 if (r < 0)
429 dev_err(&port->dev, "%s - USB control write error (%d)\n",
430 __func__, r);
431out:
432 kfree(break_reg);
433}
434
435static int ch341_tiocmset(struct tty_struct *tty,
436 unsigned int set, unsigned int clear)
437{
438 struct usb_serial_port *port = tty->driver_data;
439 struct ch341_private *priv = usb_get_serial_port_data(port);
440 unsigned long flags;
441 u8 control;
442
443 spin_lock_irqsave(&priv->lock, flags);
444 if (set & TIOCM_RTS)
445 priv->line_control |= CH341_BIT_RTS;
446 if (set & TIOCM_DTR)
447 priv->line_control |= CH341_BIT_DTR;
448 if (clear & TIOCM_RTS)
449 priv->line_control &= ~CH341_BIT_RTS;
450 if (clear & TIOCM_DTR)
451 priv->line_control &= ~CH341_BIT_DTR;
452 control = priv->line_control;
453 spin_unlock_irqrestore(&priv->lock, flags);
454
455 return ch341_set_handshake(port->serial->dev, control);
456}
457
458static void ch341_read_int_callback(struct urb *urb)
459{
460 struct usb_serial_port *port = (struct usb_serial_port *) urb->context;
461 unsigned char *data = urb->transfer_buffer;
462 unsigned int actual_length = urb->actual_length;
463 int status;
464
465 dbg("%s (%d)", __func__, port->number);
466
467 switch (urb->status) {
468 case 0:
469 /* success */
470 break;
471 case -ECONNRESET:
472 case -ENOENT:
473 case -ESHUTDOWN:
474 /* this urb is terminated, clean up */
475 dbg("%s - urb shutting down with status: %d", __func__,
476 urb->status);
477 return;
478 default:
479 dbg("%s - nonzero urb status received: %d", __func__,
480 urb->status);
481 goto exit;
482 }
483
484 usb_serial_debug_data(debug, &port->dev, __func__,
485 urb->actual_length, urb->transfer_buffer);
486
487 if (actual_length >= 4) {
488 struct ch341_private *priv = usb_get_serial_port_data(port);
489 unsigned long flags;
490 u8 prev_line_status = priv->line_status;
491
492 spin_lock_irqsave(&priv->lock, flags);
493 priv->line_status = (~(data[2])) & CH341_BITS_MODEM_STAT;
494 if ((data[1] & CH341_MULT_STAT))
495 priv->multi_status_change = 1;
496 spin_unlock_irqrestore(&priv->lock, flags);
497
498 if ((priv->line_status ^ prev_line_status) & CH341_BIT_DCD) {
499 struct tty_struct *tty = tty_port_tty_get(&port->port);
500 if (tty)
501 usb_serial_handle_dcd_change(port, tty,
502 priv->line_status & CH341_BIT_DCD);
503 tty_kref_put(tty);
504 }
505
506 wake_up_interruptible(&priv->delta_msr_wait);
507 }
508
509exit:
510 status = usb_submit_urb(urb, GFP_ATOMIC);
511 if (status)
512 dev_err(&urb->dev->dev,
513 "%s - usb_submit_urb failed with result %d\n",
514 __func__, status);
515}
516
517static int wait_modem_info(struct usb_serial_port *port, unsigned int arg)
518{
519 struct ch341_private *priv = usb_get_serial_port_data(port);
520 unsigned long flags;
521 u8 prevstatus;
522 u8 status;
523 u8 changed;
524 u8 multi_change = 0;
525
526 spin_lock_irqsave(&priv->lock, flags);
527 prevstatus = priv->line_status;
528 priv->multi_status_change = 0;
529 spin_unlock_irqrestore(&priv->lock, flags);
530
531 while (!multi_change) {
532 interruptible_sleep_on(&priv->delta_msr_wait);
533 /* see if a signal did it */
534 if (signal_pending(current))
535 return -ERESTARTSYS;
536
537 spin_lock_irqsave(&priv->lock, flags);
538 status = priv->line_status;
539 multi_change = priv->multi_status_change;
540 spin_unlock_irqrestore(&priv->lock, flags);
541
542 changed = prevstatus ^ status;
543
544 if (((arg & TIOCM_RNG) && (changed & CH341_BIT_RI)) ||
545 ((arg & TIOCM_DSR) && (changed & CH341_BIT_DSR)) ||
546 ((arg & TIOCM_CD) && (changed & CH341_BIT_DCD)) ||
547 ((arg & TIOCM_CTS) && (changed & CH341_BIT_CTS))) {
548 return 0;
549 }
550 prevstatus = status;
551 }
552
553 return 0;
554}
555
556static int ch341_ioctl(struct tty_struct *tty,
557 unsigned int cmd, unsigned long arg)
558{
559 struct usb_serial_port *port = tty->driver_data;
560 dbg("%s (%d) cmd = 0x%04x", __func__, port->number, cmd);
561
562 switch (cmd) {
563 case TIOCMIWAIT:
564 dbg("%s (%d) TIOCMIWAIT", __func__, port->number);
565 return wait_modem_info(port, arg);
566
567 default:
568 dbg("%s not supported = 0x%04x", __func__, cmd);
569 break;
570 }
571
572 return -ENOIOCTLCMD;
573}
574
575static int ch341_tiocmget(struct tty_struct *tty)
576{
577 struct usb_serial_port *port = tty->driver_data;
578 struct ch341_private *priv = usb_get_serial_port_data(port);
579 unsigned long flags;
580 u8 mcr;
581 u8 status;
582 unsigned int result;
583
584 dbg("%s (%d)", __func__, port->number);
585
586 spin_lock_irqsave(&priv->lock, flags);
587 mcr = priv->line_control;
588 status = priv->line_status;
589 spin_unlock_irqrestore(&priv->lock, flags);
590
591 result = ((mcr & CH341_BIT_DTR) ? TIOCM_DTR : 0)
592 | ((mcr & CH341_BIT_RTS) ? TIOCM_RTS : 0)
593 | ((status & CH341_BIT_CTS) ? TIOCM_CTS : 0)
594 | ((status & CH341_BIT_DSR) ? TIOCM_DSR : 0)
595 | ((status & CH341_BIT_RI) ? TIOCM_RI : 0)
596 | ((status & CH341_BIT_DCD) ? TIOCM_CD : 0);
597
598 dbg("%s - result = %x", __func__, result);
599
600 return result;
601}
602
603
604static int ch341_reset_resume(struct usb_interface *intf)
605{
606 struct usb_device *dev = interface_to_usbdev(intf);
607 struct usb_serial *serial = NULL;
608 struct ch341_private *priv;
609
610 serial = usb_get_intfdata(intf);
611 priv = usb_get_serial_port_data(serial->port[0]);
612
613 /*reconfigure ch341 serial port after bus-reset*/
614 ch341_configure(dev, priv);
615
616 usb_serial_resume(intf);
617
618 return 0;
619}
620
621static struct usb_driver ch341_driver = {
622 .name = "ch341",
623 .probe = usb_serial_probe,
624 .disconnect = usb_serial_disconnect,
625 .suspend = usb_serial_suspend,
626 .resume = usb_serial_resume,
627 .reset_resume = ch341_reset_resume,
628 .id_table = id_table,
629 .no_dynamic_id = 1,
630 .supports_autosuspend = 1,
631};
632
633static struct usb_serial_driver ch341_device = {
634 .driver = {
635 .owner = THIS_MODULE,
636 .name = "ch341-uart",
637 },
638 .id_table = id_table,
639 .usb_driver = &ch341_driver,
640 .num_ports = 1,
641 .open = ch341_open,
642 .dtr_rts = ch341_dtr_rts,
643 .carrier_raised = ch341_carrier_raised,
644 .close = ch341_close,
645 .ioctl = ch341_ioctl,
646 .set_termios = ch341_set_termios,
647 .break_ctl = ch341_break_ctl,
648 .tiocmget = ch341_tiocmget,
649 .tiocmset = ch341_tiocmset,
650 .read_int_callback = ch341_read_int_callback,
651 .attach = ch341_attach,
652};
653
654static int __init ch341_init(void)
655{
656 int retval;
657
658 retval = usb_serial_register(&ch341_device);
659 if (retval)
660 return retval;
661 retval = usb_register(&ch341_driver);
662 if (retval)
663 usb_serial_deregister(&ch341_device);
664 return retval;
665}
666
667static void __exit ch341_exit(void)
668{
669 usb_deregister(&ch341_driver);
670 usb_serial_deregister(&ch341_device);
671}
672
673module_init(ch341_init);
674module_exit(ch341_exit);
675MODULE_LICENSE("GPL");
676
677module_param(debug, bool, S_IRUGO | S_IWUSR);
678MODULE_PARM_DESC(debug, "Debug enabled or not");
679
680/* EOF ch341.c */
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/* Break support - the information used to implement this was gleaned from
52 * the Net/FreeBSD uchcom.c driver by Takanori Watanabe. Domo arigato.
53 */
54
55#define CH341_REQ_READ_VERSION 0x5F
56#define CH341_REQ_WRITE_REG 0x9A
57#define CH341_REQ_READ_REG 0x95
58#define CH341_REQ_SERIAL_INIT 0xA1
59#define CH341_REQ_MODEM_CTRL 0xA4
60
61#define CH341_REG_BREAK 0x05
62#define CH341_REG_PRESCALER 0x12
63#define CH341_REG_DIVISOR 0x13
64#define CH341_REG_LCR 0x18
65#define CH341_REG_LCR2 0x25
66
67#define CH341_NBREAK_BITS 0x01
68
69#define CH341_LCR_ENABLE_RX 0x80
70#define CH341_LCR_ENABLE_TX 0x40
71#define CH341_LCR_MARK_SPACE 0x20
72#define CH341_LCR_PAR_EVEN 0x10
73#define CH341_LCR_ENABLE_PAR 0x08
74#define CH341_LCR_STOP_BITS_2 0x04
75#define CH341_LCR_CS8 0x03
76#define CH341_LCR_CS7 0x02
77#define CH341_LCR_CS6 0x01
78#define CH341_LCR_CS5 0x00
79
80#define CH341_QUIRK_LIMITED_PRESCALER BIT(0)
81#define CH341_QUIRK_SIMULATE_BREAK BIT(1)
82
83static const struct usb_device_id id_table[] = {
84 { USB_DEVICE(0x1a86, 0x5523) },
85 { USB_DEVICE(0x1a86, 0x7522) },
86 { USB_DEVICE(0x1a86, 0x7523) },
87 { USB_DEVICE(0x2184, 0x0057) },
88 { USB_DEVICE(0x4348, 0x5523) },
89 { USB_DEVICE(0x9986, 0x7523) },
90 { },
91};
92MODULE_DEVICE_TABLE(usb, id_table);
93
94struct ch341_private {
95 spinlock_t lock; /* access lock */
96 unsigned baud_rate; /* set baud rate */
97 u8 mcr;
98 u8 msr;
99 u8 lcr;
100
101 unsigned long quirks;
102 u8 version;
103
104 unsigned long break_end;
105};
106
107static void ch341_set_termios(struct tty_struct *tty,
108 struct usb_serial_port *port,
109 const struct ktermios *old_termios);
110
111static int ch341_control_out(struct usb_device *dev, u8 request,
112 u16 value, u16 index)
113{
114 int r;
115
116 dev_dbg(&dev->dev, "%s - (%02x,%04x,%04x)\n", __func__,
117 request, value, index);
118
119 r = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), request,
120 USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT,
121 value, index, NULL, 0, DEFAULT_TIMEOUT);
122 if (r < 0)
123 dev_err(&dev->dev, "failed to send control message: %d\n", r);
124
125 return r;
126}
127
128static int ch341_control_in(struct usb_device *dev,
129 u8 request, u16 value, u16 index,
130 char *buf, unsigned bufsize)
131{
132 int r;
133
134 dev_dbg(&dev->dev, "%s - (%02x,%04x,%04x,%u)\n", __func__,
135 request, value, index, bufsize);
136
137 r = usb_control_msg_recv(dev, 0, request,
138 USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
139 value, index, buf, bufsize, DEFAULT_TIMEOUT,
140 GFP_KERNEL);
141 if (r) {
142 dev_err(&dev->dev, "failed to receive control message: %d\n",
143 r);
144 return r;
145 }
146
147 return 0;
148}
149
150#define CH341_CLKRATE 48000000
151#define CH341_CLK_DIV(ps, fact) (1 << (12 - 3 * (ps) - (fact)))
152#define CH341_MIN_RATE(ps) (CH341_CLKRATE / (CH341_CLK_DIV((ps), 1) * 512))
153
154static const speed_t ch341_min_rates[] = {
155 CH341_MIN_RATE(0),
156 CH341_MIN_RATE(1),
157 CH341_MIN_RATE(2),
158 CH341_MIN_RATE(3),
159};
160
161/* Supported range is 46 to 3000000 bps. */
162#define CH341_MIN_BPS DIV_ROUND_UP(CH341_CLKRATE, CH341_CLK_DIV(0, 0) * 256)
163#define CH341_MAX_BPS (CH341_CLKRATE / (CH341_CLK_DIV(3, 0) * 2))
164
165/*
166 * The device line speed is given by the following equation:
167 *
168 * baudrate = 48000000 / (2^(12 - 3 * ps - fact) * div), where
169 *
170 * 0 <= ps <= 3,
171 * 0 <= fact <= 1,
172 * 2 <= div <= 256 if fact = 0, or
173 * 9 <= div <= 256 if fact = 1
174 */
175static int ch341_get_divisor(struct ch341_private *priv, speed_t speed)
176{
177 unsigned int fact, div, clk_div;
178 bool force_fact0 = false;
179 int ps;
180
181 /*
182 * Clamp to supported range, this makes the (ps < 0) and (div < 2)
183 * sanity checks below redundant.
184 */
185 speed = clamp_val(speed, CH341_MIN_BPS, CH341_MAX_BPS);
186
187 /*
188 * Start with highest possible base clock (fact = 1) that will give a
189 * divisor strictly less than 512.
190 */
191 fact = 1;
192 for (ps = 3; ps >= 0; ps--) {
193 if (speed > ch341_min_rates[ps])
194 break;
195 }
196
197 if (ps < 0)
198 return -EINVAL;
199
200 /* Determine corresponding divisor, rounding down. */
201 clk_div = CH341_CLK_DIV(ps, fact);
202 div = CH341_CLKRATE / (clk_div * speed);
203
204 /* Some devices require a lower base clock if ps < 3. */
205 if (ps < 3 && (priv->quirks & CH341_QUIRK_LIMITED_PRESCALER))
206 force_fact0 = true;
207
208 /* Halve base clock (fact = 0) if required. */
209 if (div < 9 || div > 255 || force_fact0) {
210 div /= 2;
211 clk_div *= 2;
212 fact = 0;
213 }
214
215 if (div < 2)
216 return -EINVAL;
217
218 /*
219 * Pick next divisor if resulting rate is closer to the requested one,
220 * scale up to avoid rounding errors on low rates.
221 */
222 if (16 * CH341_CLKRATE / (clk_div * div) - 16 * speed >=
223 16 * speed - 16 * CH341_CLKRATE / (clk_div * (div + 1)))
224 div++;
225
226 /*
227 * Prefer lower base clock (fact = 0) if even divisor.
228 *
229 * Note that this makes the receiver more tolerant to errors.
230 */
231 if (fact == 1 && div % 2 == 0) {
232 div /= 2;
233 fact = 0;
234 }
235
236 return (0x100 - div) << 8 | fact << 2 | ps;
237}
238
239static int ch341_set_baudrate_lcr(struct usb_device *dev,
240 struct ch341_private *priv,
241 speed_t baud_rate, u8 lcr)
242{
243 int val;
244 int r;
245
246 if (!baud_rate)
247 return -EINVAL;
248
249 val = ch341_get_divisor(priv, baud_rate);
250 if (val < 0)
251 return -EINVAL;
252
253 /*
254 * CH341A buffers data until a full endpoint-size packet (32 bytes)
255 * has been received unless bit 7 is set.
256 *
257 * At least one device with version 0x27 appears to have this bit
258 * inverted.
259 */
260 if (priv->version > 0x27)
261 val |= BIT(7);
262
263 r = ch341_control_out(dev, CH341_REQ_WRITE_REG,
264 CH341_REG_DIVISOR << 8 | CH341_REG_PRESCALER,
265 val);
266 if (r)
267 return r;
268
269 /*
270 * Chip versions before version 0x30 as read using
271 * CH341_REQ_READ_VERSION used separate registers for line control
272 * (stop bits, parity and word length). Version 0x30 and above use
273 * CH341_REG_LCR only and CH341_REG_LCR2 is always set to zero.
274 */
275 if (priv->version < 0x30)
276 return 0;
277
278 r = ch341_control_out(dev, CH341_REQ_WRITE_REG,
279 CH341_REG_LCR2 << 8 | CH341_REG_LCR, lcr);
280 if (r)
281 return r;
282
283 return r;
284}
285
286static int ch341_set_handshake(struct usb_device *dev, u8 control)
287{
288 return ch341_control_out(dev, CH341_REQ_MODEM_CTRL, ~control, 0);
289}
290
291static int ch341_get_status(struct usb_device *dev, struct ch341_private *priv)
292{
293 const unsigned int size = 2;
294 u8 buffer[2];
295 int r;
296 unsigned long flags;
297
298 r = ch341_control_in(dev, CH341_REQ_READ_REG, 0x0706, 0, buffer, size);
299 if (r)
300 return r;
301
302 spin_lock_irqsave(&priv->lock, flags);
303 priv->msr = (~(*buffer)) & CH341_BITS_MODEM_STAT;
304 spin_unlock_irqrestore(&priv->lock, flags);
305
306 return 0;
307}
308
309/* -------------------------------------------------------------------------- */
310
311static int ch341_configure(struct usb_device *dev, struct ch341_private *priv)
312{
313 const unsigned int size = 2;
314 u8 buffer[2];
315 int r;
316
317 /* expect two bytes 0x27 0x00 */
318 r = ch341_control_in(dev, CH341_REQ_READ_VERSION, 0, 0, buffer, size);
319 if (r)
320 return r;
321
322 priv->version = buffer[0];
323 dev_dbg(&dev->dev, "Chip version: 0x%02x\n", priv->version);
324
325 r = ch341_control_out(dev, CH341_REQ_SERIAL_INIT, 0, 0);
326 if (r < 0)
327 return r;
328
329 r = ch341_set_baudrate_lcr(dev, priv, priv->baud_rate, priv->lcr);
330 if (r < 0)
331 return r;
332
333 r = ch341_set_handshake(dev, priv->mcr);
334 if (r < 0)
335 return r;
336
337 return 0;
338}
339
340static int ch341_detect_quirks(struct usb_serial_port *port)
341{
342 struct ch341_private *priv = usb_get_serial_port_data(port);
343 struct usb_device *udev = port->serial->dev;
344 const unsigned int size = 2;
345 unsigned long quirks = 0;
346 u8 buffer[2];
347 int r;
348
349 /*
350 * A subset of CH34x devices does not support all features. The
351 * prescaler is limited and there is no support for sending a RS232
352 * break condition. A read failure when trying to set up the latter is
353 * used to detect these devices.
354 */
355 r = usb_control_msg_recv(udev, 0, CH341_REQ_READ_REG,
356 USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
357 CH341_REG_BREAK, 0, &buffer, size,
358 DEFAULT_TIMEOUT, GFP_KERNEL);
359 if (r == -EPIPE) {
360 dev_info(&port->dev, "break control not supported, using simulated break\n");
361 quirks = CH341_QUIRK_LIMITED_PRESCALER | CH341_QUIRK_SIMULATE_BREAK;
362 r = 0;
363 } else if (r) {
364 dev_err(&port->dev, "failed to read break control: %d\n", r);
365 }
366
367 if (quirks) {
368 dev_dbg(&port->dev, "enabling quirk flags: 0x%02lx\n", quirks);
369 priv->quirks |= quirks;
370 }
371
372 return r;
373}
374
375static int ch341_port_probe(struct usb_serial_port *port)
376{
377 struct ch341_private *priv;
378 int r;
379
380 priv = kzalloc(sizeof(struct ch341_private), GFP_KERNEL);
381 if (!priv)
382 return -ENOMEM;
383
384 spin_lock_init(&priv->lock);
385 priv->baud_rate = DEFAULT_BAUD_RATE;
386 /*
387 * Some CH340 devices appear unable to change the initial LCR
388 * settings, so set a sane 8N1 default.
389 */
390 priv->lcr = CH341_LCR_ENABLE_RX | CH341_LCR_ENABLE_TX | CH341_LCR_CS8;
391
392 r = ch341_configure(port->serial->dev, priv);
393 if (r < 0)
394 goto error;
395
396 usb_set_serial_port_data(port, priv);
397
398 r = ch341_detect_quirks(port);
399 if (r < 0)
400 goto error;
401
402 return 0;
403
404error: kfree(priv);
405 return r;
406}
407
408static void ch341_port_remove(struct usb_serial_port *port)
409{
410 struct ch341_private *priv;
411
412 priv = usb_get_serial_port_data(port);
413 kfree(priv);
414}
415
416static int ch341_carrier_raised(struct usb_serial_port *port)
417{
418 struct ch341_private *priv = usb_get_serial_port_data(port);
419 if (priv->msr & CH341_BIT_DCD)
420 return 1;
421 return 0;
422}
423
424static void ch341_dtr_rts(struct usb_serial_port *port, int on)
425{
426 struct ch341_private *priv = usb_get_serial_port_data(port);
427 unsigned long flags;
428
429 /* drop DTR and RTS */
430 spin_lock_irqsave(&priv->lock, flags);
431 if (on)
432 priv->mcr |= CH341_BIT_RTS | CH341_BIT_DTR;
433 else
434 priv->mcr &= ~(CH341_BIT_RTS | CH341_BIT_DTR);
435 spin_unlock_irqrestore(&priv->lock, flags);
436 ch341_set_handshake(port->serial->dev, priv->mcr);
437}
438
439static void ch341_close(struct usb_serial_port *port)
440{
441 usb_serial_generic_close(port);
442 usb_kill_urb(port->interrupt_in_urb);
443}
444
445
446/* open this device, set default parameters */
447static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port)
448{
449 struct ch341_private *priv = usb_get_serial_port_data(port);
450 int r;
451
452 if (tty)
453 ch341_set_termios(tty, port, NULL);
454
455 dev_dbg(&port->dev, "%s - submitting interrupt urb\n", __func__);
456 r = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
457 if (r) {
458 dev_err(&port->dev, "%s - failed to submit interrupt urb: %d\n",
459 __func__, r);
460 return r;
461 }
462
463 r = ch341_get_status(port->serial->dev, priv);
464 if (r < 0) {
465 dev_err(&port->dev, "failed to read modem status: %d\n", r);
466 goto err_kill_interrupt_urb;
467 }
468
469 r = usb_serial_generic_open(tty, port);
470 if (r)
471 goto err_kill_interrupt_urb;
472
473 return 0;
474
475err_kill_interrupt_urb:
476 usb_kill_urb(port->interrupt_in_urb);
477
478 return r;
479}
480
481/* Old_termios contains the original termios settings and
482 * tty->termios contains the new setting to be used.
483 */
484static void ch341_set_termios(struct tty_struct *tty,
485 struct usb_serial_port *port,
486 const struct ktermios *old_termios)
487{
488 struct ch341_private *priv = usb_get_serial_port_data(port);
489 unsigned baud_rate;
490 unsigned long flags;
491 u8 lcr;
492 int r;
493
494 /* redundant changes may cause the chip to lose bytes */
495 if (old_termios && !tty_termios_hw_change(&tty->termios, old_termios))
496 return;
497
498 baud_rate = tty_get_baud_rate(tty);
499
500 lcr = CH341_LCR_ENABLE_RX | CH341_LCR_ENABLE_TX;
501
502 switch (C_CSIZE(tty)) {
503 case CS5:
504 lcr |= CH341_LCR_CS5;
505 break;
506 case CS6:
507 lcr |= CH341_LCR_CS6;
508 break;
509 case CS7:
510 lcr |= CH341_LCR_CS7;
511 break;
512 case CS8:
513 lcr |= CH341_LCR_CS8;
514 break;
515 }
516
517 if (C_PARENB(tty)) {
518 lcr |= CH341_LCR_ENABLE_PAR;
519 if (C_PARODD(tty) == 0)
520 lcr |= CH341_LCR_PAR_EVEN;
521 if (C_CMSPAR(tty))
522 lcr |= CH341_LCR_MARK_SPACE;
523 }
524
525 if (C_CSTOPB(tty))
526 lcr |= CH341_LCR_STOP_BITS_2;
527
528 if (baud_rate) {
529 priv->baud_rate = baud_rate;
530
531 r = ch341_set_baudrate_lcr(port->serial->dev, priv,
532 priv->baud_rate, lcr);
533 if (r < 0 && old_termios) {
534 priv->baud_rate = tty_termios_baud_rate(old_termios);
535 tty_termios_copy_hw(&tty->termios, old_termios);
536 } else if (r == 0) {
537 priv->lcr = lcr;
538 }
539 }
540
541 spin_lock_irqsave(&priv->lock, flags);
542 if (C_BAUD(tty) == B0)
543 priv->mcr &= ~(CH341_BIT_DTR | CH341_BIT_RTS);
544 else if (old_termios && (old_termios->c_cflag & CBAUD) == B0)
545 priv->mcr |= (CH341_BIT_DTR | CH341_BIT_RTS);
546 spin_unlock_irqrestore(&priv->lock, flags);
547
548 ch341_set_handshake(port->serial->dev, priv->mcr);
549}
550
551/*
552 * A subset of all CH34x devices don't support a real break condition and
553 * reading CH341_REG_BREAK fails (see also ch341_detect_quirks). This function
554 * simulates a break condition by lowering the baud rate to the minimum
555 * supported by the hardware upon enabling the break condition and sending
556 * a NUL byte.
557 *
558 * Incoming data is corrupted while the break condition is being simulated.
559 *
560 * Normally the duration of the break condition can be controlled individually
561 * by userspace using TIOCSBRK and TIOCCBRK or by passing an argument to
562 * TCSBRKP. Due to how the simulation is implemented the duration can't be
563 * controlled. The duration is always about (1s / 46bd * 9bit) = 196ms.
564 */
565static void ch341_simulate_break(struct tty_struct *tty, int break_state)
566{
567 struct usb_serial_port *port = tty->driver_data;
568 struct ch341_private *priv = usb_get_serial_port_data(port);
569 unsigned long now, delay;
570 int r;
571
572 if (break_state != 0) {
573 dev_dbg(&port->dev, "enter break state requested\n");
574
575 r = ch341_set_baudrate_lcr(port->serial->dev, priv,
576 CH341_MIN_BPS,
577 CH341_LCR_ENABLE_RX | CH341_LCR_ENABLE_TX | CH341_LCR_CS8);
578 if (r < 0) {
579 dev_err(&port->dev,
580 "failed to change baud rate to %u: %d\n",
581 CH341_MIN_BPS, r);
582 goto restore;
583 }
584
585 r = tty_put_char(tty, '\0');
586 if (r < 0) {
587 dev_err(&port->dev,
588 "failed to write NUL byte for simulated break condition: %d\n",
589 r);
590 goto restore;
591 }
592
593 /*
594 * Compute expected transmission duration including safety
595 * margin. The original baud rate is only restored after the
596 * computed point in time.
597 *
598 * 11 bits = 1 start, 8 data, 1 stop, 1 margin
599 */
600 priv->break_end = jiffies + (11 * HZ / CH341_MIN_BPS);
601
602 return;
603 }
604
605 dev_dbg(&port->dev, "leave break state requested\n");
606
607 now = jiffies;
608
609 if (time_before(now, priv->break_end)) {
610 /* Wait until NUL byte is written */
611 delay = priv->break_end - now;
612 dev_dbg(&port->dev,
613 "wait %d ms while transmitting NUL byte at %u baud\n",
614 jiffies_to_msecs(delay), CH341_MIN_BPS);
615 schedule_timeout_interruptible(delay);
616 }
617
618restore:
619 /* Restore original baud rate */
620 r = ch341_set_baudrate_lcr(port->serial->dev, priv, priv->baud_rate,
621 priv->lcr);
622 if (r < 0)
623 dev_err(&port->dev,
624 "restoring original baud rate of %u failed: %d\n",
625 priv->baud_rate, r);
626}
627
628static void ch341_break_ctl(struct tty_struct *tty, int break_state)
629{
630 const uint16_t ch341_break_reg =
631 ((uint16_t) CH341_REG_LCR << 8) | CH341_REG_BREAK;
632 struct usb_serial_port *port = tty->driver_data;
633 struct ch341_private *priv = usb_get_serial_port_data(port);
634 int r;
635 uint16_t reg_contents;
636 uint8_t break_reg[2];
637
638 if (priv->quirks & CH341_QUIRK_SIMULATE_BREAK) {
639 ch341_simulate_break(tty, break_state);
640 return;
641 }
642
643 r = ch341_control_in(port->serial->dev, CH341_REQ_READ_REG,
644 ch341_break_reg, 0, break_reg, 2);
645 if (r) {
646 dev_err(&port->dev, "%s - USB control read error (%d)\n",
647 __func__, r);
648 return;
649 }
650 dev_dbg(&port->dev, "%s - initial ch341 break register contents - reg1: %x, reg2: %x\n",
651 __func__, break_reg[0], break_reg[1]);
652 if (break_state != 0) {
653 dev_dbg(&port->dev, "%s - Enter break state requested\n", __func__);
654 break_reg[0] &= ~CH341_NBREAK_BITS;
655 break_reg[1] &= ~CH341_LCR_ENABLE_TX;
656 } else {
657 dev_dbg(&port->dev, "%s - Leave break state requested\n", __func__);
658 break_reg[0] |= CH341_NBREAK_BITS;
659 break_reg[1] |= CH341_LCR_ENABLE_TX;
660 }
661 dev_dbg(&port->dev, "%s - New ch341 break register contents - reg1: %x, reg2: %x\n",
662 __func__, break_reg[0], break_reg[1]);
663 reg_contents = get_unaligned_le16(break_reg);
664 r = ch341_control_out(port->serial->dev, CH341_REQ_WRITE_REG,
665 ch341_break_reg, reg_contents);
666 if (r < 0)
667 dev_err(&port->dev, "%s - USB control write error (%d)\n",
668 __func__, r);
669}
670
671static int ch341_tiocmset(struct tty_struct *tty,
672 unsigned int set, unsigned int clear)
673{
674 struct usb_serial_port *port = tty->driver_data;
675 struct ch341_private *priv = usb_get_serial_port_data(port);
676 unsigned long flags;
677 u8 control;
678
679 spin_lock_irqsave(&priv->lock, flags);
680 if (set & TIOCM_RTS)
681 priv->mcr |= CH341_BIT_RTS;
682 if (set & TIOCM_DTR)
683 priv->mcr |= CH341_BIT_DTR;
684 if (clear & TIOCM_RTS)
685 priv->mcr &= ~CH341_BIT_RTS;
686 if (clear & TIOCM_DTR)
687 priv->mcr &= ~CH341_BIT_DTR;
688 control = priv->mcr;
689 spin_unlock_irqrestore(&priv->lock, flags);
690
691 return ch341_set_handshake(port->serial->dev, control);
692}
693
694static void ch341_update_status(struct usb_serial_port *port,
695 unsigned char *data, size_t len)
696{
697 struct ch341_private *priv = usb_get_serial_port_data(port);
698 struct tty_struct *tty;
699 unsigned long flags;
700 u8 status;
701 u8 delta;
702
703 if (len < 4)
704 return;
705
706 status = ~data[2] & CH341_BITS_MODEM_STAT;
707
708 spin_lock_irqsave(&priv->lock, flags);
709 delta = status ^ priv->msr;
710 priv->msr = status;
711 spin_unlock_irqrestore(&priv->lock, flags);
712
713 if (data[1] & CH341_MULT_STAT)
714 dev_dbg(&port->dev, "%s - multiple status change\n", __func__);
715
716 if (!delta)
717 return;
718
719 if (delta & CH341_BIT_CTS)
720 port->icount.cts++;
721 if (delta & CH341_BIT_DSR)
722 port->icount.dsr++;
723 if (delta & CH341_BIT_RI)
724 port->icount.rng++;
725 if (delta & CH341_BIT_DCD) {
726 port->icount.dcd++;
727 tty = tty_port_tty_get(&port->port);
728 if (tty) {
729 usb_serial_handle_dcd_change(port, tty,
730 status & CH341_BIT_DCD);
731 tty_kref_put(tty);
732 }
733 }
734
735 wake_up_interruptible(&port->port.delta_msr_wait);
736}
737
738static void ch341_read_int_callback(struct urb *urb)
739{
740 struct usb_serial_port *port = urb->context;
741 unsigned char *data = urb->transfer_buffer;
742 unsigned int len = urb->actual_length;
743 int status;
744
745 switch (urb->status) {
746 case 0:
747 /* success */
748 break;
749 case -ECONNRESET:
750 case -ENOENT:
751 case -ESHUTDOWN:
752 /* this urb is terminated, clean up */
753 dev_dbg(&urb->dev->dev, "%s - urb shutting down: %d\n",
754 __func__, urb->status);
755 return;
756 default:
757 dev_dbg(&urb->dev->dev, "%s - nonzero urb status: %d\n",
758 __func__, urb->status);
759 goto exit;
760 }
761
762 usb_serial_debug_data(&port->dev, __func__, len, data);
763 ch341_update_status(port, data, len);
764exit:
765 status = usb_submit_urb(urb, GFP_ATOMIC);
766 if (status) {
767 dev_err(&urb->dev->dev, "%s - usb_submit_urb failed: %d\n",
768 __func__, status);
769 }
770}
771
772static int ch341_tiocmget(struct tty_struct *tty)
773{
774 struct usb_serial_port *port = tty->driver_data;
775 struct ch341_private *priv = usb_get_serial_port_data(port);
776 unsigned long flags;
777 u8 mcr;
778 u8 status;
779 unsigned int result;
780
781 spin_lock_irqsave(&priv->lock, flags);
782 mcr = priv->mcr;
783 status = priv->msr;
784 spin_unlock_irqrestore(&priv->lock, flags);
785
786 result = ((mcr & CH341_BIT_DTR) ? TIOCM_DTR : 0)
787 | ((mcr & CH341_BIT_RTS) ? TIOCM_RTS : 0)
788 | ((status & CH341_BIT_CTS) ? TIOCM_CTS : 0)
789 | ((status & CH341_BIT_DSR) ? TIOCM_DSR : 0)
790 | ((status & CH341_BIT_RI) ? TIOCM_RI : 0)
791 | ((status & CH341_BIT_DCD) ? TIOCM_CD : 0);
792
793 dev_dbg(&port->dev, "%s - result = %x\n", __func__, result);
794
795 return result;
796}
797
798static int ch341_reset_resume(struct usb_serial *serial)
799{
800 struct usb_serial_port *port = serial->port[0];
801 struct ch341_private *priv;
802 int ret;
803
804 priv = usb_get_serial_port_data(port);
805 if (!priv)
806 return 0;
807
808 /* reconfigure ch341 serial port after bus-reset */
809 ch341_configure(serial->dev, priv);
810
811 if (tty_port_initialized(&port->port)) {
812 ret = usb_submit_urb(port->interrupt_in_urb, GFP_NOIO);
813 if (ret) {
814 dev_err(&port->dev, "failed to submit interrupt urb: %d\n",
815 ret);
816 return ret;
817 }
818
819 ret = ch341_get_status(port->serial->dev, priv);
820 if (ret < 0) {
821 dev_err(&port->dev, "failed to read modem status: %d\n",
822 ret);
823 }
824 }
825
826 return usb_serial_generic_resume(serial);
827}
828
829static struct usb_serial_driver ch341_device = {
830 .driver = {
831 .owner = THIS_MODULE,
832 .name = "ch341-uart",
833 },
834 .id_table = id_table,
835 .num_ports = 1,
836 .open = ch341_open,
837 .dtr_rts = ch341_dtr_rts,
838 .carrier_raised = ch341_carrier_raised,
839 .close = ch341_close,
840 .set_termios = ch341_set_termios,
841 .break_ctl = ch341_break_ctl,
842 .tiocmget = ch341_tiocmget,
843 .tiocmset = ch341_tiocmset,
844 .tiocmiwait = usb_serial_generic_tiocmiwait,
845 .read_int_callback = ch341_read_int_callback,
846 .port_probe = ch341_port_probe,
847 .port_remove = ch341_port_remove,
848 .reset_resume = ch341_reset_resume,
849};
850
851static struct usb_serial_driver * const serial_drivers[] = {
852 &ch341_device, NULL
853};
854
855module_usb_serial_driver(serial_drivers, id_table);
856
857MODULE_LICENSE("GPL v2");