Loading...
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(0x4348, 0x5523) },
85 { USB_DEVICE(0x1a86, 0x7522) },
86 { USB_DEVICE(0x1a86, 0x7523) },
87 { USB_DEVICE(0x1a86, 0x5523) },
88 { },
89};
90MODULE_DEVICE_TABLE(usb, id_table);
91
92struct ch341_private {
93 spinlock_t lock; /* access lock */
94 unsigned baud_rate; /* set baud rate */
95 u8 mcr;
96 u8 msr;
97 u8 lcr;
98 unsigned long quirks;
99 unsigned long break_end;
100};
101
102static void ch341_set_termios(struct tty_struct *tty,
103 struct usb_serial_port *port,
104 struct ktermios *old_termios);
105
106static int ch341_control_out(struct usb_device *dev, u8 request,
107 u16 value, u16 index)
108{
109 int r;
110
111 dev_dbg(&dev->dev, "%s - (%02x,%04x,%04x)\n", __func__,
112 request, value, index);
113
114 r = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), request,
115 USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT,
116 value, index, NULL, 0, DEFAULT_TIMEOUT);
117 if (r < 0)
118 dev_err(&dev->dev, "failed to send control message: %d\n", r);
119
120 return r;
121}
122
123static int ch341_control_in(struct usb_device *dev,
124 u8 request, u16 value, u16 index,
125 char *buf, unsigned bufsize)
126{
127 int r;
128
129 dev_dbg(&dev->dev, "%s - (%02x,%04x,%04x,%u)\n", __func__,
130 request, value, index, bufsize);
131
132 r = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), request,
133 USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
134 value, index, buf, bufsize, DEFAULT_TIMEOUT);
135 if (r < (int)bufsize) {
136 if (r >= 0) {
137 dev_err(&dev->dev,
138 "short control message received (%d < %u)\n",
139 r, bufsize);
140 r = -EIO;
141 }
142
143 dev_err(&dev->dev, "failed to receive control message: %d\n",
144 r);
145 return r;
146 }
147
148 return 0;
149}
150
151#define CH341_CLKRATE 48000000
152#define CH341_CLK_DIV(ps, fact) (1 << (12 - 3 * (ps) - (fact)))
153#define CH341_MIN_RATE(ps) (CH341_CLKRATE / (CH341_CLK_DIV((ps), 1) * 512))
154
155static const speed_t ch341_min_rates[] = {
156 CH341_MIN_RATE(0),
157 CH341_MIN_RATE(1),
158 CH341_MIN_RATE(2),
159 CH341_MIN_RATE(3),
160};
161
162/* Supported range is 46 to 3000000 bps. */
163#define CH341_MIN_BPS DIV_ROUND_UP(CH341_CLKRATE, CH341_CLK_DIV(0, 0) * 256)
164#define CH341_MAX_BPS (CH341_CLKRATE / (CH341_CLK_DIV(3, 0) * 2))
165
166/*
167 * The device line speed is given by the following equation:
168 *
169 * baudrate = 48000000 / (2^(12 - 3 * ps - fact) * div), where
170 *
171 * 0 <= ps <= 3,
172 * 0 <= fact <= 1,
173 * 2 <= div <= 256 if fact = 0, or
174 * 9 <= div <= 256 if fact = 1
175 */
176static int ch341_get_divisor(struct ch341_private *priv, speed_t speed)
177{
178 unsigned int fact, div, clk_div;
179 bool force_fact0 = false;
180 int ps;
181
182 /*
183 * Clamp to supported range, this makes the (ps < 0) and (div < 2)
184 * sanity checks below redundant.
185 */
186 speed = clamp_val(speed, CH341_MIN_BPS, CH341_MAX_BPS);
187
188 /*
189 * Start with highest possible base clock (fact = 1) that will give a
190 * divisor strictly less than 512.
191 */
192 fact = 1;
193 for (ps = 3; ps >= 0; ps--) {
194 if (speed > ch341_min_rates[ps])
195 break;
196 }
197
198 if (ps < 0)
199 return -EINVAL;
200
201 /* Determine corresponding divisor, rounding down. */
202 clk_div = CH341_CLK_DIV(ps, fact);
203 div = CH341_CLKRATE / (clk_div * speed);
204
205 /* Some devices require a lower base clock if ps < 3. */
206 if (ps < 3 && (priv->quirks & CH341_QUIRK_LIMITED_PRESCALER))
207 force_fact0 = true;
208
209 /* Halve base clock (fact = 0) if required. */
210 if (div < 9 || div > 255 || force_fact0) {
211 div /= 2;
212 clk_div *= 2;
213 fact = 0;
214 }
215
216 if (div < 2)
217 return -EINVAL;
218
219 /*
220 * Pick next divisor if resulting rate is closer to the requested one,
221 * scale up to avoid rounding errors on low rates.
222 */
223 if (16 * CH341_CLKRATE / (clk_div * div) - 16 * speed >=
224 16 * speed - 16 * CH341_CLKRATE / (clk_div * (div + 1)))
225 div++;
226
227 /*
228 * Prefer lower base clock (fact = 0) if even divisor.
229 *
230 * Note that this makes the receiver more tolerant to errors.
231 */
232 if (fact == 1 && div % 2 == 0) {
233 div /= 2;
234 fact = 0;
235 }
236
237 return (0x100 - div) << 8 | fact << 2 | ps;
238}
239
240static int ch341_set_baudrate_lcr(struct usb_device *dev,
241 struct ch341_private *priv,
242 speed_t baud_rate, u8 lcr)
243{
244 int val;
245 int r;
246
247 if (!baud_rate)
248 return -EINVAL;
249
250 val = ch341_get_divisor(priv, baud_rate);
251 if (val < 0)
252 return -EINVAL;
253
254 /*
255 * CH341A buffers data until a full endpoint-size packet (32 bytes)
256 * has been received unless bit 7 is set.
257 */
258 val |= BIT(7);
259
260 r = ch341_control_out(dev, CH341_REQ_WRITE_REG,
261 CH341_REG_DIVISOR << 8 | CH341_REG_PRESCALER,
262 val);
263 if (r)
264 return r;
265
266 /*
267 * Chip versions before version 0x30 as read using
268 * CH341_REQ_READ_VERSION used separate registers for line control
269 * (stop bits, parity and word length). Version 0x30 and above use
270 * CH341_REG_LCR only and CH341_REG_LCR2 is always set to zero.
271 */
272 r = ch341_control_out(dev, CH341_REQ_WRITE_REG,
273 CH341_REG_LCR2 << 8 | CH341_REG_LCR, lcr);
274 if (r)
275 return r;
276
277 return r;
278}
279
280static int ch341_set_handshake(struct usb_device *dev, u8 control)
281{
282 return ch341_control_out(dev, CH341_REQ_MODEM_CTRL, ~control, 0);
283}
284
285static int ch341_get_status(struct usb_device *dev, struct ch341_private *priv)
286{
287 const unsigned int size = 2;
288 char *buffer;
289 int r;
290 unsigned long flags;
291
292 buffer = kmalloc(size, GFP_KERNEL);
293 if (!buffer)
294 return -ENOMEM;
295
296 r = ch341_control_in(dev, CH341_REQ_READ_REG, 0x0706, 0, buffer, size);
297 if (r < 0)
298 goto out;
299
300 spin_lock_irqsave(&priv->lock, flags);
301 priv->msr = (~(*buffer)) & CH341_BITS_MODEM_STAT;
302 spin_unlock_irqrestore(&priv->lock, flags);
303
304out: kfree(buffer);
305 return r;
306}
307
308/* -------------------------------------------------------------------------- */
309
310static int ch341_configure(struct usb_device *dev, struct ch341_private *priv)
311{
312 const unsigned int size = 2;
313 char *buffer;
314 int r;
315
316 buffer = kmalloc(size, GFP_KERNEL);
317 if (!buffer)
318 return -ENOMEM;
319
320 /* expect two bytes 0x27 0x00 */
321 r = ch341_control_in(dev, CH341_REQ_READ_VERSION, 0, 0, buffer, size);
322 if (r < 0)
323 goto out;
324 dev_dbg(&dev->dev, "Chip version: 0x%02x\n", buffer[0]);
325
326 r = ch341_control_out(dev, CH341_REQ_SERIAL_INIT, 0, 0);
327 if (r < 0)
328 goto out;
329
330 r = ch341_set_baudrate_lcr(dev, priv, priv->baud_rate, priv->lcr);
331 if (r < 0)
332 goto out;
333
334 r = ch341_set_handshake(dev, priv->mcr);
335
336out: kfree(buffer);
337 return r;
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 char *buffer;
347 int r;
348
349 buffer = kmalloc(size, GFP_KERNEL);
350 if (!buffer)
351 return -ENOMEM;
352
353 /*
354 * A subset of CH34x devices does not support all features. The
355 * prescaler is limited and there is no support for sending a RS232
356 * break condition. A read failure when trying to set up the latter is
357 * used to detect these devices.
358 */
359 r = usb_control_msg(udev, usb_rcvctrlpipe(udev, 0), CH341_REQ_READ_REG,
360 USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
361 CH341_REG_BREAK, 0, buffer, size, DEFAULT_TIMEOUT);
362 if (r == -EPIPE) {
363 dev_info(&port->dev, "break control not supported, using simulated break\n");
364 quirks = CH341_QUIRK_LIMITED_PRESCALER | CH341_QUIRK_SIMULATE_BREAK;
365 r = 0;
366 goto out;
367 }
368
369 if (r != size) {
370 if (r >= 0)
371 r = -EIO;
372 dev_err(&port->dev, "failed to read break control: %d\n", r);
373 goto out;
374 }
375
376 r = 0;
377out:
378 kfree(buffer);
379
380 if (quirks) {
381 dev_dbg(&port->dev, "enabling quirk flags: 0x%02lx\n", quirks);
382 priv->quirks |= quirks;
383 }
384
385 return r;
386}
387
388static int ch341_port_probe(struct usb_serial_port *port)
389{
390 struct ch341_private *priv;
391 int r;
392
393 priv = kzalloc(sizeof(struct ch341_private), GFP_KERNEL);
394 if (!priv)
395 return -ENOMEM;
396
397 spin_lock_init(&priv->lock);
398 priv->baud_rate = DEFAULT_BAUD_RATE;
399 /*
400 * Some CH340 devices appear unable to change the initial LCR
401 * settings, so set a sane 8N1 default.
402 */
403 priv->lcr = CH341_LCR_ENABLE_RX | CH341_LCR_ENABLE_TX | CH341_LCR_CS8;
404
405 r = ch341_configure(port->serial->dev, priv);
406 if (r < 0)
407 goto error;
408
409 usb_set_serial_port_data(port, priv);
410
411 r = ch341_detect_quirks(port);
412 if (r < 0)
413 goto error;
414
415 return 0;
416
417error: kfree(priv);
418 return r;
419}
420
421static int ch341_port_remove(struct usb_serial_port *port)
422{
423 struct ch341_private *priv;
424
425 priv = usb_get_serial_port_data(port);
426 kfree(priv);
427
428 return 0;
429}
430
431static int ch341_carrier_raised(struct usb_serial_port *port)
432{
433 struct ch341_private *priv = usb_get_serial_port_data(port);
434 if (priv->msr & CH341_BIT_DCD)
435 return 1;
436 return 0;
437}
438
439static void ch341_dtr_rts(struct usb_serial_port *port, int on)
440{
441 struct ch341_private *priv = usb_get_serial_port_data(port);
442 unsigned long flags;
443
444 /* drop DTR and RTS */
445 spin_lock_irqsave(&priv->lock, flags);
446 if (on)
447 priv->mcr |= CH341_BIT_RTS | CH341_BIT_DTR;
448 else
449 priv->mcr &= ~(CH341_BIT_RTS | CH341_BIT_DTR);
450 spin_unlock_irqrestore(&priv->lock, flags);
451 ch341_set_handshake(port->serial->dev, priv->mcr);
452}
453
454static void ch341_close(struct usb_serial_port *port)
455{
456 usb_serial_generic_close(port);
457 usb_kill_urb(port->interrupt_in_urb);
458}
459
460
461/* open this device, set default parameters */
462static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port)
463{
464 struct ch341_private *priv = usb_get_serial_port_data(port);
465 int r;
466
467 if (tty)
468 ch341_set_termios(tty, port, NULL);
469
470 dev_dbg(&port->dev, "%s - submitting interrupt urb\n", __func__);
471 r = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
472 if (r) {
473 dev_err(&port->dev, "%s - failed to submit interrupt urb: %d\n",
474 __func__, r);
475 return r;
476 }
477
478 r = ch341_get_status(port->serial->dev, priv);
479 if (r < 0) {
480 dev_err(&port->dev, "failed to read modem status: %d\n", r);
481 goto err_kill_interrupt_urb;
482 }
483
484 r = usb_serial_generic_open(tty, port);
485 if (r)
486 goto err_kill_interrupt_urb;
487
488 return 0;
489
490err_kill_interrupt_urb:
491 usb_kill_urb(port->interrupt_in_urb);
492
493 return r;
494}
495
496/* Old_termios contains the original termios settings and
497 * tty->termios contains the new setting to be used.
498 */
499static void ch341_set_termios(struct tty_struct *tty,
500 struct usb_serial_port *port, struct ktermios *old_termios)
501{
502 struct ch341_private *priv = usb_get_serial_port_data(port);
503 unsigned baud_rate;
504 unsigned long flags;
505 u8 lcr;
506 int r;
507
508 /* redundant changes may cause the chip to lose bytes */
509 if (old_termios && !tty_termios_hw_change(&tty->termios, old_termios))
510 return;
511
512 baud_rate = tty_get_baud_rate(tty);
513
514 lcr = CH341_LCR_ENABLE_RX | CH341_LCR_ENABLE_TX;
515
516 switch (C_CSIZE(tty)) {
517 case CS5:
518 lcr |= CH341_LCR_CS5;
519 break;
520 case CS6:
521 lcr |= CH341_LCR_CS6;
522 break;
523 case CS7:
524 lcr |= CH341_LCR_CS7;
525 break;
526 case CS8:
527 lcr |= CH341_LCR_CS8;
528 break;
529 }
530
531 if (C_PARENB(tty)) {
532 lcr |= CH341_LCR_ENABLE_PAR;
533 if (C_PARODD(tty) == 0)
534 lcr |= CH341_LCR_PAR_EVEN;
535 if (C_CMSPAR(tty))
536 lcr |= CH341_LCR_MARK_SPACE;
537 }
538
539 if (C_CSTOPB(tty))
540 lcr |= CH341_LCR_STOP_BITS_2;
541
542 if (baud_rate) {
543 priv->baud_rate = baud_rate;
544
545 r = ch341_set_baudrate_lcr(port->serial->dev, priv,
546 priv->baud_rate, lcr);
547 if (r < 0 && old_termios) {
548 priv->baud_rate = tty_termios_baud_rate(old_termios);
549 tty_termios_copy_hw(&tty->termios, old_termios);
550 } else if (r == 0) {
551 priv->lcr = lcr;
552 }
553 }
554
555 spin_lock_irqsave(&priv->lock, flags);
556 if (C_BAUD(tty) == B0)
557 priv->mcr &= ~(CH341_BIT_DTR | CH341_BIT_RTS);
558 else if (old_termios && (old_termios->c_cflag & CBAUD) == B0)
559 priv->mcr |= (CH341_BIT_DTR | CH341_BIT_RTS);
560 spin_unlock_irqrestore(&priv->lock, flags);
561
562 ch341_set_handshake(port->serial->dev, priv->mcr);
563}
564
565/*
566 * A subset of all CH34x devices don't support a real break condition and
567 * reading CH341_REG_BREAK fails (see also ch341_detect_quirks). This function
568 * simulates a break condition by lowering the baud rate to the minimum
569 * supported by the hardware upon enabling the break condition and sending
570 * a NUL byte.
571 *
572 * Incoming data is corrupted while the break condition is being simulated.
573 *
574 * Normally the duration of the break condition can be controlled individually
575 * by userspace using TIOCSBRK and TIOCCBRK or by passing an argument to
576 * TCSBRKP. Due to how the simulation is implemented the duration can't be
577 * controlled. The duration is always about (1s / 46bd * 9bit) = 196ms.
578 */
579static void ch341_simulate_break(struct tty_struct *tty, int break_state)
580{
581 struct usb_serial_port *port = tty->driver_data;
582 struct ch341_private *priv = usb_get_serial_port_data(port);
583 unsigned long now, delay;
584 int r;
585
586 if (break_state != 0) {
587 dev_dbg(&port->dev, "enter break state requested\n");
588
589 r = ch341_set_baudrate_lcr(port->serial->dev, priv,
590 CH341_MIN_BPS,
591 CH341_LCR_ENABLE_RX | CH341_LCR_ENABLE_TX | CH341_LCR_CS8);
592 if (r < 0) {
593 dev_err(&port->dev,
594 "failed to change baud rate to %u: %d\n",
595 CH341_MIN_BPS, r);
596 goto restore;
597 }
598
599 r = tty_put_char(tty, '\0');
600 if (r < 0) {
601 dev_err(&port->dev,
602 "failed to write NUL byte for simulated break condition: %d\n",
603 r);
604 goto restore;
605 }
606
607 /*
608 * Compute expected transmission duration including safety
609 * margin. The original baud rate is only restored after the
610 * computed point in time.
611 *
612 * 11 bits = 1 start, 8 data, 1 stop, 1 margin
613 */
614 priv->break_end = jiffies + (11 * HZ / CH341_MIN_BPS);
615
616 return;
617 }
618
619 dev_dbg(&port->dev, "leave break state requested\n");
620
621 now = jiffies;
622
623 if (time_before(now, priv->break_end)) {
624 /* Wait until NUL byte is written */
625 delay = priv->break_end - now;
626 dev_dbg(&port->dev,
627 "wait %d ms while transmitting NUL byte at %u baud\n",
628 jiffies_to_msecs(delay), CH341_MIN_BPS);
629 schedule_timeout_interruptible(delay);
630 }
631
632restore:
633 /* Restore original baud rate */
634 r = ch341_set_baudrate_lcr(port->serial->dev, priv, priv->baud_rate,
635 priv->lcr);
636 if (r < 0)
637 dev_err(&port->dev,
638 "restoring original baud rate of %u failed: %d\n",
639 priv->baud_rate, r);
640}
641
642static void ch341_break_ctl(struct tty_struct *tty, int break_state)
643{
644 const uint16_t ch341_break_reg =
645 ((uint16_t) CH341_REG_LCR << 8) | CH341_REG_BREAK;
646 struct usb_serial_port *port = tty->driver_data;
647 struct ch341_private *priv = usb_get_serial_port_data(port);
648 int r;
649 uint16_t reg_contents;
650 uint8_t *break_reg;
651
652 if (priv->quirks & CH341_QUIRK_SIMULATE_BREAK) {
653 ch341_simulate_break(tty, break_state);
654 return;
655 }
656
657 break_reg = kmalloc(2, GFP_KERNEL);
658 if (!break_reg)
659 return;
660
661 r = ch341_control_in(port->serial->dev, CH341_REQ_READ_REG,
662 ch341_break_reg, 0, break_reg, 2);
663 if (r < 0) {
664 dev_err(&port->dev, "%s - USB control read error (%d)\n",
665 __func__, r);
666 goto out;
667 }
668 dev_dbg(&port->dev, "%s - initial ch341 break register contents - reg1: %x, reg2: %x\n",
669 __func__, break_reg[0], break_reg[1]);
670 if (break_state != 0) {
671 dev_dbg(&port->dev, "%s - Enter break state requested\n", __func__);
672 break_reg[0] &= ~CH341_NBREAK_BITS;
673 break_reg[1] &= ~CH341_LCR_ENABLE_TX;
674 } else {
675 dev_dbg(&port->dev, "%s - Leave break state requested\n", __func__);
676 break_reg[0] |= CH341_NBREAK_BITS;
677 break_reg[1] |= CH341_LCR_ENABLE_TX;
678 }
679 dev_dbg(&port->dev, "%s - New ch341 break register contents - reg1: %x, reg2: %x\n",
680 __func__, break_reg[0], break_reg[1]);
681 reg_contents = get_unaligned_le16(break_reg);
682 r = ch341_control_out(port->serial->dev, CH341_REQ_WRITE_REG,
683 ch341_break_reg, reg_contents);
684 if (r < 0)
685 dev_err(&port->dev, "%s - USB control write error (%d)\n",
686 __func__, r);
687out:
688 kfree(break_reg);
689}
690
691static int ch341_tiocmset(struct tty_struct *tty,
692 unsigned int set, unsigned int clear)
693{
694 struct usb_serial_port *port = tty->driver_data;
695 struct ch341_private *priv = usb_get_serial_port_data(port);
696 unsigned long flags;
697 u8 control;
698
699 spin_lock_irqsave(&priv->lock, flags);
700 if (set & TIOCM_RTS)
701 priv->mcr |= CH341_BIT_RTS;
702 if (set & TIOCM_DTR)
703 priv->mcr |= CH341_BIT_DTR;
704 if (clear & TIOCM_RTS)
705 priv->mcr &= ~CH341_BIT_RTS;
706 if (clear & TIOCM_DTR)
707 priv->mcr &= ~CH341_BIT_DTR;
708 control = priv->mcr;
709 spin_unlock_irqrestore(&priv->lock, flags);
710
711 return ch341_set_handshake(port->serial->dev, control);
712}
713
714static void ch341_update_status(struct usb_serial_port *port,
715 unsigned char *data, size_t len)
716{
717 struct ch341_private *priv = usb_get_serial_port_data(port);
718 struct tty_struct *tty;
719 unsigned long flags;
720 u8 status;
721 u8 delta;
722
723 if (len < 4)
724 return;
725
726 status = ~data[2] & CH341_BITS_MODEM_STAT;
727
728 spin_lock_irqsave(&priv->lock, flags);
729 delta = status ^ priv->msr;
730 priv->msr = status;
731 spin_unlock_irqrestore(&priv->lock, flags);
732
733 if (data[1] & CH341_MULT_STAT)
734 dev_dbg(&port->dev, "%s - multiple status change\n", __func__);
735
736 if (!delta)
737 return;
738
739 if (delta & CH341_BIT_CTS)
740 port->icount.cts++;
741 if (delta & CH341_BIT_DSR)
742 port->icount.dsr++;
743 if (delta & CH341_BIT_RI)
744 port->icount.rng++;
745 if (delta & CH341_BIT_DCD) {
746 port->icount.dcd++;
747 tty = tty_port_tty_get(&port->port);
748 if (tty) {
749 usb_serial_handle_dcd_change(port, tty,
750 status & CH341_BIT_DCD);
751 tty_kref_put(tty);
752 }
753 }
754
755 wake_up_interruptible(&port->port.delta_msr_wait);
756}
757
758static void ch341_read_int_callback(struct urb *urb)
759{
760 struct usb_serial_port *port = urb->context;
761 unsigned char *data = urb->transfer_buffer;
762 unsigned int len = urb->actual_length;
763 int status;
764
765 switch (urb->status) {
766 case 0:
767 /* success */
768 break;
769 case -ECONNRESET:
770 case -ENOENT:
771 case -ESHUTDOWN:
772 /* this urb is terminated, clean up */
773 dev_dbg(&urb->dev->dev, "%s - urb shutting down: %d\n",
774 __func__, urb->status);
775 return;
776 default:
777 dev_dbg(&urb->dev->dev, "%s - nonzero urb status: %d\n",
778 __func__, urb->status);
779 goto exit;
780 }
781
782 usb_serial_debug_data(&port->dev, __func__, len, data);
783 ch341_update_status(port, data, len);
784exit:
785 status = usb_submit_urb(urb, GFP_ATOMIC);
786 if (status) {
787 dev_err(&urb->dev->dev, "%s - usb_submit_urb failed: %d\n",
788 __func__, status);
789 }
790}
791
792static int ch341_tiocmget(struct tty_struct *tty)
793{
794 struct usb_serial_port *port = tty->driver_data;
795 struct ch341_private *priv = usb_get_serial_port_data(port);
796 unsigned long flags;
797 u8 mcr;
798 u8 status;
799 unsigned int result;
800
801 spin_lock_irqsave(&priv->lock, flags);
802 mcr = priv->mcr;
803 status = priv->msr;
804 spin_unlock_irqrestore(&priv->lock, flags);
805
806 result = ((mcr & CH341_BIT_DTR) ? TIOCM_DTR : 0)
807 | ((mcr & CH341_BIT_RTS) ? TIOCM_RTS : 0)
808 | ((status & CH341_BIT_CTS) ? TIOCM_CTS : 0)
809 | ((status & CH341_BIT_DSR) ? TIOCM_DSR : 0)
810 | ((status & CH341_BIT_RI) ? TIOCM_RI : 0)
811 | ((status & CH341_BIT_DCD) ? TIOCM_CD : 0);
812
813 dev_dbg(&port->dev, "%s - result = %x\n", __func__, result);
814
815 return result;
816}
817
818static int ch341_reset_resume(struct usb_serial *serial)
819{
820 struct usb_serial_port *port = serial->port[0];
821 struct ch341_private *priv;
822 int ret;
823
824 priv = usb_get_serial_port_data(port);
825 if (!priv)
826 return 0;
827
828 /* reconfigure ch341 serial port after bus-reset */
829 ch341_configure(serial->dev, priv);
830
831 if (tty_port_initialized(&port->port)) {
832 ret = usb_submit_urb(port->interrupt_in_urb, GFP_NOIO);
833 if (ret) {
834 dev_err(&port->dev, "failed to submit interrupt urb: %d\n",
835 ret);
836 return ret;
837 }
838
839 ret = ch341_get_status(port->serial->dev, priv);
840 if (ret < 0) {
841 dev_err(&port->dev, "failed to read modem status: %d\n",
842 ret);
843 }
844 }
845
846 return usb_serial_generic_resume(serial);
847}
848
849static struct usb_serial_driver ch341_device = {
850 .driver = {
851 .owner = THIS_MODULE,
852 .name = "ch341-uart",
853 },
854 .id_table = id_table,
855 .num_ports = 1,
856 .open = ch341_open,
857 .dtr_rts = ch341_dtr_rts,
858 .carrier_raised = ch341_carrier_raised,
859 .close = ch341_close,
860 .set_termios = ch341_set_termios,
861 .break_ctl = ch341_break_ctl,
862 .tiocmget = ch341_tiocmget,
863 .tiocmset = ch341_tiocmset,
864 .tiocmiwait = usb_serial_generic_tiocmiwait,
865 .read_int_callback = ch341_read_int_callback,
866 .port_probe = ch341_port_probe,
867 .port_remove = ch341_port_remove,
868 .reset_resume = ch341_reset_resume,
869};
870
871static struct usb_serial_driver * const serial_drivers[] = {
872 &ch341_device, NULL
873};
874
875module_usb_serial_driver(serial_drivers, id_table);
876
877MODULE_LICENSE("GPL v2");
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 bool 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 if (!priv->baud_rate)
129 return -EINVAL;
130 factor = (CH341_BAUDBASE_FACTOR / priv->baud_rate);
131 divisor = CH341_BAUDBASE_DIVMAX;
132
133 while ((factor > 0xfff0) && divisor) {
134 factor >>= 3;
135 divisor--;
136 }
137
138 if (factor > 0xfff0)
139 return -EINVAL;
140
141 factor = 0x10000 - factor;
142 a = (factor & 0xff00) | divisor;
143 b = factor & 0xff;
144
145 r = ch341_control_out(dev, 0x9a, 0x1312, a);
146 if (!r)
147 r = ch341_control_out(dev, 0x9a, 0x0f2c, b);
148
149 return r;
150}
151
152static int ch341_set_handshake(struct usb_device *dev, u8 control)
153{
154 return ch341_control_out(dev, 0xa4, ~control, 0);
155}
156
157static int ch341_get_status(struct usb_device *dev, struct ch341_private *priv)
158{
159 char *buffer;
160 int r;
161 const unsigned size = 8;
162 unsigned long flags;
163
164 buffer = kmalloc(size, GFP_KERNEL);
165 if (!buffer)
166 return -ENOMEM;
167
168 r = ch341_control_in(dev, 0x95, 0x0706, 0, buffer, size);
169 if (r < 0)
170 goto out;
171
172 /* setup the private status if available */
173 if (r == 2) {
174 r = 0;
175 spin_lock_irqsave(&priv->lock, flags);
176 priv->line_status = (~(*buffer)) & CH341_BITS_MODEM_STAT;
177 priv->multi_status_change = 0;
178 spin_unlock_irqrestore(&priv->lock, flags);
179 } else
180 r = -EPROTO;
181
182out: kfree(buffer);
183 return r;
184}
185
186/* -------------------------------------------------------------------------- */
187
188static int ch341_configure(struct usb_device *dev, struct ch341_private *priv)
189{
190 char *buffer;
191 int r;
192 const unsigned size = 8;
193
194 buffer = kmalloc(size, GFP_KERNEL);
195 if (!buffer)
196 return -ENOMEM;
197
198 /* expect two bytes 0x27 0x00 */
199 r = ch341_control_in(dev, 0x5f, 0, 0, buffer, size);
200 if (r < 0)
201 goto out;
202
203 r = ch341_control_out(dev, 0xa1, 0, 0);
204 if (r < 0)
205 goto out;
206
207 r = ch341_set_baudrate(dev, priv);
208 if (r < 0)
209 goto out;
210
211 /* expect two bytes 0x56 0x00 */
212 r = ch341_control_in(dev, 0x95, 0x2518, 0, buffer, size);
213 if (r < 0)
214 goto out;
215
216 r = ch341_control_out(dev, 0x9a, 0x2518, 0x0050);
217 if (r < 0)
218 goto out;
219
220 /* expect 0xff 0xee */
221 r = ch341_get_status(dev, priv);
222 if (r < 0)
223 goto out;
224
225 r = ch341_control_out(dev, 0xa1, 0x501f, 0xd90a);
226 if (r < 0)
227 goto out;
228
229 r = ch341_set_baudrate(dev, priv);
230 if (r < 0)
231 goto out;
232
233 r = ch341_set_handshake(dev, priv->line_control);
234 if (r < 0)
235 goto out;
236
237 /* expect 0x9f 0xee */
238 r = ch341_get_status(dev, priv);
239
240out: kfree(buffer);
241 return r;
242}
243
244/* allocate private data */
245static int ch341_attach(struct usb_serial *serial)
246{
247 struct ch341_private *priv;
248 int r;
249
250 /* private data */
251 priv = kzalloc(sizeof(struct ch341_private), GFP_KERNEL);
252 if (!priv)
253 return -ENOMEM;
254
255 spin_lock_init(&priv->lock);
256 init_waitqueue_head(&priv->delta_msr_wait);
257 priv->baud_rate = DEFAULT_BAUD_RATE;
258 priv->line_control = CH341_BIT_RTS | CH341_BIT_DTR;
259
260 r = ch341_configure(serial->dev, priv);
261 if (r < 0)
262 goto error;
263
264 usb_set_serial_port_data(serial->port[0], priv);
265 return 0;
266
267error: kfree(priv);
268 return r;
269}
270
271static int ch341_carrier_raised(struct usb_serial_port *port)
272{
273 struct ch341_private *priv = usb_get_serial_port_data(port);
274 if (priv->line_status & CH341_BIT_DCD)
275 return 1;
276 return 0;
277}
278
279static void ch341_dtr_rts(struct usb_serial_port *port, int on)
280{
281 struct ch341_private *priv = usb_get_serial_port_data(port);
282 unsigned long flags;
283
284 /* drop DTR and RTS */
285 spin_lock_irqsave(&priv->lock, flags);
286 if (on)
287 priv->line_control |= CH341_BIT_RTS | CH341_BIT_DTR;
288 else
289 priv->line_control &= ~(CH341_BIT_RTS | CH341_BIT_DTR);
290 spin_unlock_irqrestore(&priv->lock, flags);
291 ch341_set_handshake(port->serial->dev, priv->line_control);
292 wake_up_interruptible(&priv->delta_msr_wait);
293}
294
295static void ch341_close(struct usb_serial_port *port)
296{
297 usb_serial_generic_close(port);
298 usb_kill_urb(port->interrupt_in_urb);
299}
300
301
302/* open this device, set default parameters */
303static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port)
304{
305 struct usb_serial *serial = port->serial;
306 struct ch341_private *priv = usb_get_serial_port_data(serial->port[0]);
307 int r;
308
309 priv->baud_rate = DEFAULT_BAUD_RATE;
310
311 r = ch341_configure(serial->dev, priv);
312 if (r)
313 goto out;
314
315 r = ch341_set_handshake(serial->dev, priv->line_control);
316 if (r)
317 goto out;
318
319 r = ch341_set_baudrate(serial->dev, priv);
320 if (r)
321 goto out;
322
323 dbg("%s - submitting interrupt urb", __func__);
324 r = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
325 if (r) {
326 dev_err(&port->dev, "%s - failed submitting interrupt urb,"
327 " error %d\n", __func__, r);
328 ch341_close(port);
329 goto out;
330 }
331
332 r = usb_serial_generic_open(tty, port);
333
334out: return r;
335}
336
337/* Old_termios contains the original termios settings and
338 * tty->termios contains the new setting to be used.
339 */
340static void ch341_set_termios(struct tty_struct *tty,
341 struct usb_serial_port *port, struct ktermios *old_termios)
342{
343 struct ch341_private *priv = usb_get_serial_port_data(port);
344 unsigned baud_rate;
345 unsigned long flags;
346
347 baud_rate = tty_get_baud_rate(tty);
348
349 priv->baud_rate = baud_rate;
350
351 if (baud_rate) {
352 spin_lock_irqsave(&priv->lock, flags);
353 priv->line_control |= (CH341_BIT_DTR | CH341_BIT_RTS);
354 spin_unlock_irqrestore(&priv->lock, flags);
355 ch341_set_baudrate(port->serial->dev, priv);
356 } else {
357 spin_lock_irqsave(&priv->lock, flags);
358 priv->line_control &= ~(CH341_BIT_DTR | CH341_BIT_RTS);
359 spin_unlock_irqrestore(&priv->lock, flags);
360 }
361
362 ch341_set_handshake(port->serial->dev, priv->line_control);
363
364 /* Unimplemented:
365 * (cflag & CSIZE) : data bits [5, 8]
366 * (cflag & PARENB) : parity {NONE, EVEN, ODD}
367 * (cflag & CSTOPB) : stop bits [1, 2]
368 */
369}
370
371static void ch341_break_ctl(struct tty_struct *tty, int break_state)
372{
373 const uint16_t ch341_break_reg =
374 CH341_REG_BREAK1 | ((uint16_t) CH341_REG_BREAK2 << 8);
375 struct usb_serial_port *port = tty->driver_data;
376 int r;
377 uint16_t reg_contents;
378 uint8_t *break_reg;
379
380 break_reg = kmalloc(2, GFP_KERNEL);
381 if (!break_reg) {
382 dev_err(&port->dev, "%s - kmalloc failed\n", __func__);
383 return;
384 }
385
386 r = ch341_control_in(port->serial->dev, CH341_REQ_READ_REG,
387 ch341_break_reg, 0, break_reg, 2);
388 if (r < 0) {
389 dev_err(&port->dev, "%s - USB control read error (%d)\n",
390 __func__, r);
391 goto out;
392 }
393 dbg("%s - initial ch341 break register contents - reg1: %x, reg2: %x",
394 __func__, break_reg[0], break_reg[1]);
395 if (break_state != 0) {
396 dbg("%s - Enter break state requested", __func__);
397 break_reg[0] &= ~CH341_NBREAK_BITS_REG1;
398 break_reg[1] &= ~CH341_NBREAK_BITS_REG2;
399 } else {
400 dbg("%s - Leave break state requested", __func__);
401 break_reg[0] |= CH341_NBREAK_BITS_REG1;
402 break_reg[1] |= CH341_NBREAK_BITS_REG2;
403 }
404 dbg("%s - New ch341 break register contents - reg1: %x, reg2: %x",
405 __func__, break_reg[0], break_reg[1]);
406 reg_contents = get_unaligned_le16(break_reg);
407 r = ch341_control_out(port->serial->dev, CH341_REQ_WRITE_REG,
408 ch341_break_reg, reg_contents);
409 if (r < 0)
410 dev_err(&port->dev, "%s - USB control write error (%d)\n",
411 __func__, r);
412out:
413 kfree(break_reg);
414}
415
416static int ch341_tiocmset(struct tty_struct *tty,
417 unsigned int set, unsigned int clear)
418{
419 struct usb_serial_port *port = tty->driver_data;
420 struct ch341_private *priv = usb_get_serial_port_data(port);
421 unsigned long flags;
422 u8 control;
423
424 spin_lock_irqsave(&priv->lock, flags);
425 if (set & TIOCM_RTS)
426 priv->line_control |= CH341_BIT_RTS;
427 if (set & TIOCM_DTR)
428 priv->line_control |= CH341_BIT_DTR;
429 if (clear & TIOCM_RTS)
430 priv->line_control &= ~CH341_BIT_RTS;
431 if (clear & TIOCM_DTR)
432 priv->line_control &= ~CH341_BIT_DTR;
433 control = priv->line_control;
434 spin_unlock_irqrestore(&priv->lock, flags);
435
436 return ch341_set_handshake(port->serial->dev, control);
437}
438
439static void ch341_read_int_callback(struct urb *urb)
440{
441 struct usb_serial_port *port = (struct usb_serial_port *) urb->context;
442 unsigned char *data = urb->transfer_buffer;
443 unsigned int actual_length = urb->actual_length;
444 int status;
445
446 switch (urb->status) {
447 case 0:
448 /* success */
449 break;
450 case -ECONNRESET:
451 case -ENOENT:
452 case -ESHUTDOWN:
453 /* this urb is terminated, clean up */
454 dbg("%s - urb shutting down with status: %d", __func__,
455 urb->status);
456 return;
457 default:
458 dbg("%s - nonzero urb status received: %d", __func__,
459 urb->status);
460 goto exit;
461 }
462
463 usb_serial_debug_data(debug, &port->dev, __func__,
464 urb->actual_length, urb->transfer_buffer);
465
466 if (actual_length >= 4) {
467 struct ch341_private *priv = usb_get_serial_port_data(port);
468 unsigned long flags;
469 u8 prev_line_status = priv->line_status;
470
471 spin_lock_irqsave(&priv->lock, flags);
472 priv->line_status = (~(data[2])) & CH341_BITS_MODEM_STAT;
473 if ((data[1] & CH341_MULT_STAT))
474 priv->multi_status_change = 1;
475 spin_unlock_irqrestore(&priv->lock, flags);
476
477 if ((priv->line_status ^ prev_line_status) & CH341_BIT_DCD) {
478 struct tty_struct *tty = tty_port_tty_get(&port->port);
479 if (tty)
480 usb_serial_handle_dcd_change(port, tty,
481 priv->line_status & CH341_BIT_DCD);
482 tty_kref_put(tty);
483 }
484
485 wake_up_interruptible(&priv->delta_msr_wait);
486 }
487
488exit:
489 status = usb_submit_urb(urb, GFP_ATOMIC);
490 if (status)
491 dev_err(&urb->dev->dev,
492 "%s - usb_submit_urb failed with result %d\n",
493 __func__, status);
494}
495
496static int wait_modem_info(struct usb_serial_port *port, unsigned int arg)
497{
498 struct ch341_private *priv = usb_get_serial_port_data(port);
499 unsigned long flags;
500 u8 prevstatus;
501 u8 status;
502 u8 changed;
503 u8 multi_change = 0;
504
505 spin_lock_irqsave(&priv->lock, flags);
506 prevstatus = priv->line_status;
507 priv->multi_status_change = 0;
508 spin_unlock_irqrestore(&priv->lock, flags);
509
510 while (!multi_change) {
511 interruptible_sleep_on(&priv->delta_msr_wait);
512 /* see if a signal did it */
513 if (signal_pending(current))
514 return -ERESTARTSYS;
515
516 spin_lock_irqsave(&priv->lock, flags);
517 status = priv->line_status;
518 multi_change = priv->multi_status_change;
519 spin_unlock_irqrestore(&priv->lock, flags);
520
521 changed = prevstatus ^ status;
522
523 if (((arg & TIOCM_RNG) && (changed & CH341_BIT_RI)) ||
524 ((arg & TIOCM_DSR) && (changed & CH341_BIT_DSR)) ||
525 ((arg & TIOCM_CD) && (changed & CH341_BIT_DCD)) ||
526 ((arg & TIOCM_CTS) && (changed & CH341_BIT_CTS))) {
527 return 0;
528 }
529 prevstatus = status;
530 }
531
532 return 0;
533}
534
535static int ch341_ioctl(struct tty_struct *tty,
536 unsigned int cmd, unsigned long arg)
537{
538 struct usb_serial_port *port = tty->driver_data;
539 dbg("%s (%d) cmd = 0x%04x", __func__, port->number, cmd);
540
541 switch (cmd) {
542 case TIOCMIWAIT:
543 dbg("%s (%d) TIOCMIWAIT", __func__, port->number);
544 return wait_modem_info(port, arg);
545
546 default:
547 dbg("%s not supported = 0x%04x", __func__, cmd);
548 break;
549 }
550
551 return -ENOIOCTLCMD;
552}
553
554static int ch341_tiocmget(struct tty_struct *tty)
555{
556 struct usb_serial_port *port = tty->driver_data;
557 struct ch341_private *priv = usb_get_serial_port_data(port);
558 unsigned long flags;
559 u8 mcr;
560 u8 status;
561 unsigned int result;
562
563 spin_lock_irqsave(&priv->lock, flags);
564 mcr = priv->line_control;
565 status = priv->line_status;
566 spin_unlock_irqrestore(&priv->lock, flags);
567
568 result = ((mcr & CH341_BIT_DTR) ? TIOCM_DTR : 0)
569 | ((mcr & CH341_BIT_RTS) ? TIOCM_RTS : 0)
570 | ((status & CH341_BIT_CTS) ? TIOCM_CTS : 0)
571 | ((status & CH341_BIT_DSR) ? TIOCM_DSR : 0)
572 | ((status & CH341_BIT_RI) ? TIOCM_RI : 0)
573 | ((status & CH341_BIT_DCD) ? TIOCM_CD : 0);
574
575 dbg("%s - result = %x", __func__, result);
576
577 return result;
578}
579
580static int ch341_reset_resume(struct usb_serial *serial)
581{
582 struct ch341_private *priv;
583
584 priv = usb_get_serial_port_data(serial->port[0]);
585
586 /* reconfigure ch341 serial port after bus-reset */
587 ch341_configure(serial->dev, priv);
588
589 return 0;
590}
591
592static struct usb_serial_driver ch341_device = {
593 .driver = {
594 .owner = THIS_MODULE,
595 .name = "ch341-uart",
596 },
597 .id_table = id_table,
598 .num_ports = 1,
599 .open = ch341_open,
600 .dtr_rts = ch341_dtr_rts,
601 .carrier_raised = ch341_carrier_raised,
602 .close = ch341_close,
603 .ioctl = ch341_ioctl,
604 .set_termios = ch341_set_termios,
605 .break_ctl = ch341_break_ctl,
606 .tiocmget = ch341_tiocmget,
607 .tiocmset = ch341_tiocmset,
608 .read_int_callback = ch341_read_int_callback,
609 .attach = ch341_attach,
610 .reset_resume = ch341_reset_resume,
611};
612
613static struct usb_serial_driver * const serial_drivers[] = {
614 &ch341_device, NULL
615};
616
617module_usb_serial_driver(serial_drivers, id_table);
618
619MODULE_LICENSE("GPL");
620
621module_param(debug, bool, S_IRUGO | S_IWUSR);
622MODULE_PARM_DESC(debug, "Debug enabled or not");