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1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Copyright (C) 2009 by Bart Hartgers (bart.hartgers+ark3116@gmail.com)
4 * Original version:
5 * Copyright (C) 2006
6 * Simon Schulz (ark3116_driver <at> auctionant.de)
7 *
8 * ark3116
9 * - implements a driver for the arkmicro ark3116 chipset (vendor=0x6547,
10 * productid=0x0232) (used in a datacable called KQ-U8A)
11 *
12 * Supports full modem status lines, break, hardware flow control. Does not
13 * support software flow control, since I do not know how to enable it in hw.
14 *
15 * This driver is a essentially new implementation. I initially dug
16 * into the old ark3116.c driver and suddenly realized the ark3116 is
17 * a 16450 with a USB interface glued to it. See comments at the
18 * bottom of this file.
19 */
20
21#include <linux/kernel.h>
22#include <linux/ioctl.h>
23#include <linux/tty.h>
24#include <linux/slab.h>
25#include <linux/tty_flip.h>
26#include <linux/module.h>
27#include <linux/usb.h>
28#include <linux/usb/serial.h>
29#include <linux/serial.h>
30#include <linux/serial_reg.h>
31#include <linux/uaccess.h>
32#include <linux/mutex.h>
33#include <linux/spinlock.h>
34
35#define DRIVER_AUTHOR "Bart Hartgers <bart.hartgers+ark3116@gmail.com>"
36#define DRIVER_DESC "USB ARK3116 serial/IrDA driver"
37#define DRIVER_DEV_DESC "ARK3116 RS232/IrDA"
38#define DRIVER_NAME "ark3116"
39
40/* usb timeout of 1 second */
41#define ARK_TIMEOUT 1000
42
43static const struct usb_device_id id_table[] = {
44 { USB_DEVICE(0x6547, 0x0232) },
45 { USB_DEVICE(0x18ec, 0x3118) }, /* USB to IrDA adapter */
46 { },
47};
48MODULE_DEVICE_TABLE(usb, id_table);
49
50static int is_irda(struct usb_serial *serial)
51{
52 struct usb_device *dev = serial->dev;
53 if (le16_to_cpu(dev->descriptor.idVendor) == 0x18ec &&
54 le16_to_cpu(dev->descriptor.idProduct) == 0x3118)
55 return 1;
56 return 0;
57}
58
59struct ark3116_private {
60 int irda; /* 1 for irda device */
61
62 /* protects hw register updates */
63 struct mutex hw_lock;
64
65 int quot; /* baudrate divisor */
66 __u32 lcr; /* line control register value */
67 __u32 hcr; /* handshake control register (0x8)
68 * value */
69 __u32 mcr; /* modem control register value */
70
71 /* protects the status values below */
72 spinlock_t status_lock;
73 __u32 msr; /* modem status register value */
74 __u32 lsr; /* line status register value */
75};
76
77static int ark3116_write_reg(struct usb_serial *serial,
78 unsigned reg, __u8 val)
79{
80 int result;
81 /* 0xfe 0x40 are magic values taken from original driver */
82 result = usb_control_msg(serial->dev,
83 usb_sndctrlpipe(serial->dev, 0),
84 0xfe, 0x40, val, reg,
85 NULL, 0, ARK_TIMEOUT);
86 if (result)
87 return result;
88
89 return 0;
90}
91
92static int ark3116_read_reg(struct usb_serial *serial,
93 unsigned reg, unsigned char *buf)
94{
95 int result;
96 /* 0xfe 0xc0 are magic values taken from original driver */
97 result = usb_control_msg(serial->dev,
98 usb_rcvctrlpipe(serial->dev, 0),
99 0xfe, 0xc0, 0, reg,
100 buf, 1, ARK_TIMEOUT);
101 if (result < 1) {
102 dev_err(&serial->interface->dev,
103 "failed to read register %u: %d\n",
104 reg, result);
105 if (result >= 0)
106 result = -EIO;
107
108 return result;
109 }
110
111 return 0;
112}
113
114static inline int calc_divisor(int bps)
115{
116 /* Original ark3116 made some exceptions in rounding here
117 * because windows did the same. Assume that is not really
118 * necessary.
119 * Crystal is 12MHz, probably because of USB, but we divide by 4?
120 */
121 return (12000000 + 2*bps) / (4*bps);
122}
123
124static int ark3116_port_probe(struct usb_serial_port *port)
125{
126 struct usb_serial *serial = port->serial;
127 struct ark3116_private *priv;
128
129 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
130 if (!priv)
131 return -ENOMEM;
132
133 mutex_init(&priv->hw_lock);
134 spin_lock_init(&priv->status_lock);
135
136 priv->irda = is_irda(serial);
137
138 usb_set_serial_port_data(port, priv);
139
140 /* setup the hardware */
141 ark3116_write_reg(serial, UART_IER, 0);
142 /* disable DMA */
143 ark3116_write_reg(serial, UART_FCR, 0);
144 /* handshake control */
145 priv->hcr = 0;
146 ark3116_write_reg(serial, 0x8 , 0);
147 /* modem control */
148 priv->mcr = 0;
149 ark3116_write_reg(serial, UART_MCR, 0);
150
151 if (!(priv->irda)) {
152 ark3116_write_reg(serial, 0xb , 0);
153 } else {
154 ark3116_write_reg(serial, 0xb , 1);
155 ark3116_write_reg(serial, 0xc , 0);
156 ark3116_write_reg(serial, 0xd , 0x41);
157 ark3116_write_reg(serial, 0xa , 1);
158 }
159
160 /* setup baudrate */
161 ark3116_write_reg(serial, UART_LCR, UART_LCR_DLAB);
162
163 /* setup for 9600 8N1 */
164 priv->quot = calc_divisor(9600);
165 ark3116_write_reg(serial, UART_DLL, priv->quot & 0xff);
166 ark3116_write_reg(serial, UART_DLM, (priv->quot>>8) & 0xff);
167
168 priv->lcr = UART_LCR_WLEN8;
169 ark3116_write_reg(serial, UART_LCR, UART_LCR_WLEN8);
170
171 ark3116_write_reg(serial, 0xe, 0);
172
173 if (priv->irda)
174 ark3116_write_reg(serial, 0x9, 0);
175
176 dev_info(&port->dev, "using %s mode\n", priv->irda ? "IrDA" : "RS232");
177
178 return 0;
179}
180
181static void ark3116_port_remove(struct usb_serial_port *port)
182{
183 struct ark3116_private *priv = usb_get_serial_port_data(port);
184
185 /* device is closed, so URBs and DMA should be down */
186 mutex_destroy(&priv->hw_lock);
187 kfree(priv);
188}
189
190static void ark3116_set_termios(struct tty_struct *tty,
191 struct usb_serial_port *port,
192 const struct ktermios *old_termios)
193{
194 struct usb_serial *serial = port->serial;
195 struct ark3116_private *priv = usb_get_serial_port_data(port);
196 struct ktermios *termios = &tty->termios;
197 unsigned int cflag = termios->c_cflag;
198 int bps = tty_get_baud_rate(tty);
199 int quot;
200 __u8 lcr, hcr, eval;
201
202 /* set data bit count */
203 lcr = UART_LCR_WLEN(tty_get_char_size(cflag));
204
205 if (cflag & CSTOPB)
206 lcr |= UART_LCR_STOP;
207 if (cflag & PARENB)
208 lcr |= UART_LCR_PARITY;
209 if (!(cflag & PARODD))
210 lcr |= UART_LCR_EPAR;
211 if (cflag & CMSPAR)
212 lcr |= UART_LCR_SPAR;
213
214 /* handshake control */
215 hcr = (cflag & CRTSCTS) ? 0x03 : 0x00;
216
217 /* calc baudrate */
218 dev_dbg(&port->dev, "%s - setting bps to %d\n", __func__, bps);
219 eval = 0;
220 switch (bps) {
221 case 0:
222 quot = calc_divisor(9600);
223 break;
224 default:
225 if ((bps < 75) || (bps > 3000000))
226 bps = 9600;
227 quot = calc_divisor(bps);
228 break;
229 case 460800:
230 eval = 1;
231 quot = calc_divisor(bps);
232 break;
233 case 921600:
234 eval = 2;
235 quot = calc_divisor(bps);
236 break;
237 }
238
239 /* Update state: synchronize */
240 mutex_lock(&priv->hw_lock);
241
242 /* keep old LCR_SBC bit */
243 lcr |= (priv->lcr & UART_LCR_SBC);
244
245 dev_dbg(&port->dev, "%s - setting hcr:0x%02x,lcr:0x%02x,quot:%d\n",
246 __func__, hcr, lcr, quot);
247
248 /* handshake control */
249 if (priv->hcr != hcr) {
250 priv->hcr = hcr;
251 ark3116_write_reg(serial, 0x8, hcr);
252 }
253
254 /* baudrate */
255 if (priv->quot != quot) {
256 priv->quot = quot;
257 priv->lcr = lcr; /* need to write lcr anyway */
258
259 /* disable DMA since transmit/receive is
260 * shadowed by UART_DLL
261 */
262 ark3116_write_reg(serial, UART_FCR, 0);
263
264 ark3116_write_reg(serial, UART_LCR,
265 lcr|UART_LCR_DLAB);
266 ark3116_write_reg(serial, UART_DLL, quot & 0xff);
267 ark3116_write_reg(serial, UART_DLM, (quot>>8) & 0xff);
268
269 /* restore lcr */
270 ark3116_write_reg(serial, UART_LCR, lcr);
271 /* magic baudrate thingy: not sure what it does,
272 * but windows does this as well.
273 */
274 ark3116_write_reg(serial, 0xe, eval);
275
276 /* enable DMA */
277 ark3116_write_reg(serial, UART_FCR, UART_FCR_DMA_SELECT);
278 } else if (priv->lcr != lcr) {
279 priv->lcr = lcr;
280 ark3116_write_reg(serial, UART_LCR, lcr);
281 }
282
283 mutex_unlock(&priv->hw_lock);
284
285 /* check for software flow control */
286 if (I_IXOFF(tty) || I_IXON(tty)) {
287 dev_warn(&port->dev,
288 "software flow control not implemented\n");
289 }
290
291 /* Don't rewrite B0 */
292 if (tty_termios_baud_rate(termios))
293 tty_termios_encode_baud_rate(termios, bps, bps);
294}
295
296static void ark3116_close(struct usb_serial_port *port)
297{
298 struct usb_serial *serial = port->serial;
299
300 /* disable DMA */
301 ark3116_write_reg(serial, UART_FCR, 0);
302
303 /* deactivate interrupts */
304 ark3116_write_reg(serial, UART_IER, 0);
305
306 usb_serial_generic_close(port);
307
308 usb_kill_urb(port->interrupt_in_urb);
309}
310
311static int ark3116_open(struct tty_struct *tty, struct usb_serial_port *port)
312{
313 struct ark3116_private *priv = usb_get_serial_port_data(port);
314 struct usb_serial *serial = port->serial;
315 unsigned char *buf;
316 int result;
317
318 buf = kmalloc(1, GFP_KERNEL);
319 if (buf == NULL)
320 return -ENOMEM;
321
322 result = usb_serial_generic_open(tty, port);
323 if (result) {
324 dev_dbg(&port->dev,
325 "%s - usb_serial_generic_open failed: %d\n",
326 __func__, result);
327 goto err_free;
328 }
329
330 /* remove any data still left: also clears error state */
331 ark3116_read_reg(serial, UART_RX, buf);
332
333 /* read modem status */
334 result = ark3116_read_reg(serial, UART_MSR, buf);
335 if (result)
336 goto err_close;
337 priv->msr = *buf;
338
339 /* read line status */
340 result = ark3116_read_reg(serial, UART_LSR, buf);
341 if (result)
342 goto err_close;
343 priv->lsr = *buf;
344
345 result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
346 if (result) {
347 dev_err(&port->dev, "submit irq_in urb failed %d\n",
348 result);
349 goto err_close;
350 }
351
352 /* activate interrupts */
353 ark3116_write_reg(port->serial, UART_IER, UART_IER_MSI|UART_IER_RLSI);
354
355 /* enable DMA */
356 ark3116_write_reg(port->serial, UART_FCR, UART_FCR_DMA_SELECT);
357
358 /* setup termios */
359 if (tty)
360 ark3116_set_termios(tty, port, NULL);
361
362 kfree(buf);
363
364 return 0;
365
366err_close:
367 usb_serial_generic_close(port);
368err_free:
369 kfree(buf);
370
371 return result;
372}
373
374static int ark3116_tiocmget(struct tty_struct *tty)
375{
376 struct usb_serial_port *port = tty->driver_data;
377 struct ark3116_private *priv = usb_get_serial_port_data(port);
378 __u32 status;
379 __u32 ctrl;
380 unsigned long flags;
381
382 mutex_lock(&priv->hw_lock);
383 ctrl = priv->mcr;
384 mutex_unlock(&priv->hw_lock);
385
386 spin_lock_irqsave(&priv->status_lock, flags);
387 status = priv->msr;
388 spin_unlock_irqrestore(&priv->status_lock, flags);
389
390 return (status & UART_MSR_DSR ? TIOCM_DSR : 0) |
391 (status & UART_MSR_CTS ? TIOCM_CTS : 0) |
392 (status & UART_MSR_RI ? TIOCM_RI : 0) |
393 (status & UART_MSR_DCD ? TIOCM_CD : 0) |
394 (ctrl & UART_MCR_DTR ? TIOCM_DTR : 0) |
395 (ctrl & UART_MCR_RTS ? TIOCM_RTS : 0) |
396 (ctrl & UART_MCR_OUT1 ? TIOCM_OUT1 : 0) |
397 (ctrl & UART_MCR_OUT2 ? TIOCM_OUT2 : 0);
398}
399
400static int ark3116_tiocmset(struct tty_struct *tty,
401 unsigned set, unsigned clr)
402{
403 struct usb_serial_port *port = tty->driver_data;
404 struct ark3116_private *priv = usb_get_serial_port_data(port);
405
406 /* we need to take the mutex here, to make sure that the value
407 * in priv->mcr is actually the one that is in the hardware
408 */
409
410 mutex_lock(&priv->hw_lock);
411
412 if (set & TIOCM_RTS)
413 priv->mcr |= UART_MCR_RTS;
414 if (set & TIOCM_DTR)
415 priv->mcr |= UART_MCR_DTR;
416 if (set & TIOCM_OUT1)
417 priv->mcr |= UART_MCR_OUT1;
418 if (set & TIOCM_OUT2)
419 priv->mcr |= UART_MCR_OUT2;
420 if (clr & TIOCM_RTS)
421 priv->mcr &= ~UART_MCR_RTS;
422 if (clr & TIOCM_DTR)
423 priv->mcr &= ~UART_MCR_DTR;
424 if (clr & TIOCM_OUT1)
425 priv->mcr &= ~UART_MCR_OUT1;
426 if (clr & TIOCM_OUT2)
427 priv->mcr &= ~UART_MCR_OUT2;
428
429 ark3116_write_reg(port->serial, UART_MCR, priv->mcr);
430
431 mutex_unlock(&priv->hw_lock);
432
433 return 0;
434}
435
436static int ark3116_break_ctl(struct tty_struct *tty, int break_state)
437{
438 struct usb_serial_port *port = tty->driver_data;
439 struct ark3116_private *priv = usb_get_serial_port_data(port);
440 int ret;
441
442 /* LCR is also used for other things: protect access */
443 mutex_lock(&priv->hw_lock);
444
445 if (break_state)
446 priv->lcr |= UART_LCR_SBC;
447 else
448 priv->lcr &= ~UART_LCR_SBC;
449
450 ret = ark3116_write_reg(port->serial, UART_LCR, priv->lcr);
451
452 mutex_unlock(&priv->hw_lock);
453
454 return ret;
455}
456
457static void ark3116_update_msr(struct usb_serial_port *port, __u8 msr)
458{
459 struct ark3116_private *priv = usb_get_serial_port_data(port);
460 unsigned long flags;
461
462 spin_lock_irqsave(&priv->status_lock, flags);
463 priv->msr = msr;
464 spin_unlock_irqrestore(&priv->status_lock, flags);
465
466 if (msr & UART_MSR_ANY_DELTA) {
467 /* update input line counters */
468 if (msr & UART_MSR_DCTS)
469 port->icount.cts++;
470 if (msr & UART_MSR_DDSR)
471 port->icount.dsr++;
472 if (msr & UART_MSR_DDCD)
473 port->icount.dcd++;
474 if (msr & UART_MSR_TERI)
475 port->icount.rng++;
476 wake_up_interruptible(&port->port.delta_msr_wait);
477 }
478}
479
480static void ark3116_update_lsr(struct usb_serial_port *port, __u8 lsr)
481{
482 struct ark3116_private *priv = usb_get_serial_port_data(port);
483 unsigned long flags;
484
485 spin_lock_irqsave(&priv->status_lock, flags);
486 /* combine bits */
487 priv->lsr |= lsr;
488 spin_unlock_irqrestore(&priv->status_lock, flags);
489
490 if (lsr&UART_LSR_BRK_ERROR_BITS) {
491 if (lsr & UART_LSR_BI)
492 port->icount.brk++;
493 if (lsr & UART_LSR_FE)
494 port->icount.frame++;
495 if (lsr & UART_LSR_PE)
496 port->icount.parity++;
497 if (lsr & UART_LSR_OE)
498 port->icount.overrun++;
499 }
500}
501
502static void ark3116_read_int_callback(struct urb *urb)
503{
504 struct usb_serial_port *port = urb->context;
505 int status = urb->status;
506 const __u8 *data = urb->transfer_buffer;
507 int result;
508
509 switch (status) {
510 case -ECONNRESET:
511 case -ENOENT:
512 case -ESHUTDOWN:
513 /* this urb is terminated, clean up */
514 dev_dbg(&port->dev, "%s - urb shutting down with status: %d\n",
515 __func__, status);
516 return;
517 default:
518 dev_dbg(&port->dev, "%s - nonzero urb status received: %d\n",
519 __func__, status);
520 break;
521 case 0: /* success */
522 /* discovered this by trail and error... */
523 if ((urb->actual_length == 4) && (data[0] == 0xe8)) {
524 const __u8 id = data[1]&UART_IIR_ID;
525 dev_dbg(&port->dev, "%s: iir=%02x\n", __func__, data[1]);
526 if (id == UART_IIR_MSI) {
527 dev_dbg(&port->dev, "%s: msr=%02x\n",
528 __func__, data[3]);
529 ark3116_update_msr(port, data[3]);
530 break;
531 } else if (id == UART_IIR_RLSI) {
532 dev_dbg(&port->dev, "%s: lsr=%02x\n",
533 __func__, data[2]);
534 ark3116_update_lsr(port, data[2]);
535 break;
536 }
537 }
538 /*
539 * Not sure what this data meant...
540 */
541 usb_serial_debug_data(&port->dev, __func__,
542 urb->actual_length,
543 urb->transfer_buffer);
544 break;
545 }
546
547 result = usb_submit_urb(urb, GFP_ATOMIC);
548 if (result)
549 dev_err(&port->dev, "failed to resubmit interrupt urb: %d\n",
550 result);
551}
552
553
554/* Data comes in via the bulk (data) URB, errors/interrupts via the int URB.
555 * This means that we cannot be sure which data byte has an associated error
556 * condition, so we report an error for all data in the next bulk read.
557 *
558 * Actually, there might even be a window between the bulk data leaving the
559 * ark and reading/resetting the lsr in the read_bulk_callback where an
560 * interrupt for the next data block could come in.
561 * Without somekind of ordering on the ark, we would have to report the
562 * error for the next block of data as well...
563 * For now, let's pretend this can't happen.
564 */
565static void ark3116_process_read_urb(struct urb *urb)
566{
567 struct usb_serial_port *port = urb->context;
568 struct ark3116_private *priv = usb_get_serial_port_data(port);
569 unsigned char *data = urb->transfer_buffer;
570 char tty_flag = TTY_NORMAL;
571 unsigned long flags;
572 __u32 lsr;
573
574 /* update line status */
575 spin_lock_irqsave(&priv->status_lock, flags);
576 lsr = priv->lsr;
577 priv->lsr &= ~UART_LSR_BRK_ERROR_BITS;
578 spin_unlock_irqrestore(&priv->status_lock, flags);
579
580 if (!urb->actual_length)
581 return;
582
583 if (lsr & UART_LSR_BRK_ERROR_BITS) {
584 if (lsr & UART_LSR_BI)
585 tty_flag = TTY_BREAK;
586 else if (lsr & UART_LSR_PE)
587 tty_flag = TTY_PARITY;
588 else if (lsr & UART_LSR_FE)
589 tty_flag = TTY_FRAME;
590
591 /* overrun is special, not associated with a char */
592 if (lsr & UART_LSR_OE)
593 tty_insert_flip_char(&port->port, 0, TTY_OVERRUN);
594 }
595 tty_insert_flip_string_fixed_flag(&port->port, data, tty_flag,
596 urb->actual_length);
597 tty_flip_buffer_push(&port->port);
598}
599
600static struct usb_serial_driver ark3116_device = {
601 .driver = {
602 .owner = THIS_MODULE,
603 .name = "ark3116",
604 },
605 .id_table = id_table,
606 .num_ports = 1,
607 .num_bulk_in = 1,
608 .num_bulk_out = 1,
609 .num_interrupt_in = 1,
610 .port_probe = ark3116_port_probe,
611 .port_remove = ark3116_port_remove,
612 .set_termios = ark3116_set_termios,
613 .tiocmget = ark3116_tiocmget,
614 .tiocmset = ark3116_tiocmset,
615 .tiocmiwait = usb_serial_generic_tiocmiwait,
616 .get_icount = usb_serial_generic_get_icount,
617 .open = ark3116_open,
618 .close = ark3116_close,
619 .break_ctl = ark3116_break_ctl,
620 .read_int_callback = ark3116_read_int_callback,
621 .process_read_urb = ark3116_process_read_urb,
622};
623
624static struct usb_serial_driver * const serial_drivers[] = {
625 &ark3116_device, NULL
626};
627
628module_usb_serial_driver(serial_drivers, id_table);
629
630MODULE_LICENSE("GPL");
631
632MODULE_AUTHOR(DRIVER_AUTHOR);
633MODULE_DESCRIPTION(DRIVER_DESC);
634
635/*
636 * The following describes what I learned from studying the old
637 * ark3116.c driver, disassembling the windows driver, and some lucky
638 * guesses. Since I do not have any datasheet or other
639 * documentation, inaccuracies are almost guaranteed.
640 *
641 * Some specs for the ARK3116 can be found here:
642 * http://web.archive.org/web/20060318000438/
643 * www.arkmicro.com/en/products/view.php?id=10
644 * On that page, 2 GPIO pins are mentioned: I assume these are the
645 * OUT1 and OUT2 pins of the UART, so I added support for those
646 * through the MCR. Since the pins are not available on my hardware,
647 * I could not verify this.
648 * Also, it states there is "on-chip hardware flow control". I have
649 * discovered how to enable that. Unfortunately, I do not know how to
650 * enable XON/XOFF (software) flow control, which would need support
651 * from the chip as well to work. Because of the wording on the web
652 * page there is a real possibility the chip simply does not support
653 * software flow control.
654 *
655 * I got my ark3116 as part of a mobile phone adapter cable. On the
656 * PCB, the following numbered contacts are present:
657 *
658 * 1:- +5V
659 * 2:o DTR
660 * 3:i RX
661 * 4:i DCD
662 * 5:o RTS
663 * 6:o TX
664 * 7:i RI
665 * 8:i DSR
666 * 10:- 0V
667 * 11:i CTS
668 *
669 * On my chip, all signals seem to be 3.3V, but 5V tolerant. But that
670 * may be different for the one you have ;-).
671 *
672 * The windows driver limits the registers to 0-F, so I assume there
673 * are actually 16 present on the device.
674 *
675 * On an UART interrupt, 4 bytes of data come in on the interrupt
676 * endpoint. The bytes are 0xe8 IIR LSR MSR.
677 *
678 * The baudrate seems to be generated from the 12MHz crystal, using
679 * 4-times subsampling. So quot=12e6/(4*baud). Also see description
680 * of register E.
681 *
682 * Registers 0-7:
683 * These seem to be the same as for a regular 16450. The FCR is set
684 * to UART_FCR_DMA_SELECT (0x8), I guess to enable transfers between
685 * the UART and the USB bridge/DMA engine.
686 *
687 * Register 8:
688 * By trial and error, I found out that bit 0 enables hardware CTS,
689 * stopping TX when CTS is +5V. Bit 1 does the same for RTS, making
690 * RTS +5V when the 3116 cannot transfer the data to the USB bus
691 * (verified by disabling the reading URB). Note that as far as I can
692 * tell, the windows driver does NOT use this, so there might be some
693 * hardware bug or something.
694 *
695 * According to a patch provided here
696 * https://lore.kernel.org/lkml/200907261419.50702.linux@rainbow-software.org
697 * the ARK3116 can also be used as an IrDA dongle. Since I do not have
698 * such a thing, I could not investigate that aspect. However, I can
699 * speculate ;-).
700 *
701 * - IrDA encodes data differently than RS232. Most likely, one of
702 * the bits in registers 9..E enables the IR ENDEC (encoder/decoder).
703 * - Depending on the IR transceiver, the input and output need to be
704 * inverted, so there are probably bits for that as well.
705 * - IrDA is half-duplex, so there should be a bit for selecting that.
706 *
707 * This still leaves at least two registers unaccounted for. Perhaps
708 * The chip can do XON/XOFF or CRC in HW?
709 *
710 * Register 9:
711 * Set to 0x00 for IrDA, when the baudrate is initialised.
712 *
713 * Register A:
714 * Set to 0x01 for IrDA, at init.
715 *
716 * Register B:
717 * Set to 0x01 for IrDA, 0x00 for RS232, at init.
718 *
719 * Register C:
720 * Set to 00 for IrDA, at init.
721 *
722 * Register D:
723 * Set to 0x41 for IrDA, at init.
724 *
725 * Register E:
726 * Somekind of baudrate override. The windows driver seems to set
727 * this to 0x00 for normal baudrates, 0x01 for 460800, 0x02 for 921600.
728 * Since 460800 and 921600 cannot be obtained by dividing 3MHz by an integer,
729 * it could be somekind of subdivisor thingy.
730 * However,it does not seem to do anything: selecting 921600 (divisor 3,
731 * reg E=2), still gets 1 MHz. I also checked if registers 9, C or F would
732 * work, but they don't.
733 *
734 * Register F: unknown
735 */
1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Copyright (C) 2009 by Bart Hartgers (bart.hartgers+ark3116@gmail.com)
4 * Original version:
5 * Copyright (C) 2006
6 * Simon Schulz (ark3116_driver <at> auctionant.de)
7 *
8 * ark3116
9 * - implements a driver for the arkmicro ark3116 chipset (vendor=0x6547,
10 * productid=0x0232) (used in a datacable called KQ-U8A)
11 *
12 * Supports full modem status lines, break, hardware flow control. Does not
13 * support software flow control, since I do not know how to enable it in hw.
14 *
15 * This driver is a essentially new implementation. I initially dug
16 * into the old ark3116.c driver and suddenly realized the ark3116 is
17 * a 16450 with a USB interface glued to it. See comments at the
18 * bottom of this file.
19 */
20
21#include <linux/kernel.h>
22#include <linux/ioctl.h>
23#include <linux/tty.h>
24#include <linux/slab.h>
25#include <linux/tty_flip.h>
26#include <linux/module.h>
27#include <linux/usb.h>
28#include <linux/usb/serial.h>
29#include <linux/serial.h>
30#include <linux/serial_reg.h>
31#include <linux/uaccess.h>
32#include <linux/mutex.h>
33#include <linux/spinlock.h>
34
35#define DRIVER_AUTHOR "Bart Hartgers <bart.hartgers+ark3116@gmail.com>"
36#define DRIVER_DESC "USB ARK3116 serial/IrDA driver"
37#define DRIVER_DEV_DESC "ARK3116 RS232/IrDA"
38#define DRIVER_NAME "ark3116"
39
40/* usb timeout of 1 second */
41#define ARK_TIMEOUT 1000
42
43static const struct usb_device_id id_table[] = {
44 { USB_DEVICE(0x6547, 0x0232) },
45 { USB_DEVICE(0x18ec, 0x3118) }, /* USB to IrDA adapter */
46 { },
47};
48MODULE_DEVICE_TABLE(usb, id_table);
49
50static int is_irda(struct usb_serial *serial)
51{
52 struct usb_device *dev = serial->dev;
53 if (le16_to_cpu(dev->descriptor.idVendor) == 0x18ec &&
54 le16_to_cpu(dev->descriptor.idProduct) == 0x3118)
55 return 1;
56 return 0;
57}
58
59struct ark3116_private {
60 int irda; /* 1 for irda device */
61
62 /* protects hw register updates */
63 struct mutex hw_lock;
64
65 int quot; /* baudrate divisor */
66 __u32 lcr; /* line control register value */
67 __u32 hcr; /* handshake control register (0x8)
68 * value */
69 __u32 mcr; /* modem control register value */
70
71 /* protects the status values below */
72 spinlock_t status_lock;
73 __u32 msr; /* modem status register value */
74 __u32 lsr; /* line status register value */
75};
76
77static int ark3116_write_reg(struct usb_serial *serial,
78 unsigned reg, __u8 val)
79{
80 int result;
81 /* 0xfe 0x40 are magic values taken from original driver */
82 result = usb_control_msg(serial->dev,
83 usb_sndctrlpipe(serial->dev, 0),
84 0xfe, 0x40, val, reg,
85 NULL, 0, ARK_TIMEOUT);
86 if (result)
87 return result;
88
89 return 0;
90}
91
92static int ark3116_read_reg(struct usb_serial *serial,
93 unsigned reg, unsigned char *buf)
94{
95 int result;
96 /* 0xfe 0xc0 are magic values taken from original driver */
97 result = usb_control_msg(serial->dev,
98 usb_rcvctrlpipe(serial->dev, 0),
99 0xfe, 0xc0, 0, reg,
100 buf, 1, ARK_TIMEOUT);
101 if (result < 1) {
102 dev_err(&serial->interface->dev,
103 "failed to read register %u: %d\n",
104 reg, result);
105 if (result >= 0)
106 result = -EIO;
107
108 return result;
109 }
110
111 return 0;
112}
113
114static inline int calc_divisor(int bps)
115{
116 /* Original ark3116 made some exceptions in rounding here
117 * because windows did the same. Assume that is not really
118 * necessary.
119 * Crystal is 12MHz, probably because of USB, but we divide by 4?
120 */
121 return (12000000 + 2*bps) / (4*bps);
122}
123
124static int ark3116_port_probe(struct usb_serial_port *port)
125{
126 struct usb_serial *serial = port->serial;
127 struct ark3116_private *priv;
128
129 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
130 if (!priv)
131 return -ENOMEM;
132
133 mutex_init(&priv->hw_lock);
134 spin_lock_init(&priv->status_lock);
135
136 priv->irda = is_irda(serial);
137
138 usb_set_serial_port_data(port, priv);
139
140 /* setup the hardware */
141 ark3116_write_reg(serial, UART_IER, 0);
142 /* disable DMA */
143 ark3116_write_reg(serial, UART_FCR, 0);
144 /* handshake control */
145 priv->hcr = 0;
146 ark3116_write_reg(serial, 0x8 , 0);
147 /* modem control */
148 priv->mcr = 0;
149 ark3116_write_reg(serial, UART_MCR, 0);
150
151 if (!(priv->irda)) {
152 ark3116_write_reg(serial, 0xb , 0);
153 } else {
154 ark3116_write_reg(serial, 0xb , 1);
155 ark3116_write_reg(serial, 0xc , 0);
156 ark3116_write_reg(serial, 0xd , 0x41);
157 ark3116_write_reg(serial, 0xa , 1);
158 }
159
160 /* setup baudrate */
161 ark3116_write_reg(serial, UART_LCR, UART_LCR_DLAB);
162
163 /* setup for 9600 8N1 */
164 priv->quot = calc_divisor(9600);
165 ark3116_write_reg(serial, UART_DLL, priv->quot & 0xff);
166 ark3116_write_reg(serial, UART_DLM, (priv->quot>>8) & 0xff);
167
168 priv->lcr = UART_LCR_WLEN8;
169 ark3116_write_reg(serial, UART_LCR, UART_LCR_WLEN8);
170
171 ark3116_write_reg(serial, 0xe, 0);
172
173 if (priv->irda)
174 ark3116_write_reg(serial, 0x9, 0);
175
176 dev_info(&port->dev, "using %s mode\n", priv->irda ? "IrDA" : "RS232");
177
178 return 0;
179}
180
181static int ark3116_port_remove(struct usb_serial_port *port)
182{
183 struct ark3116_private *priv = usb_get_serial_port_data(port);
184
185 /* device is closed, so URBs and DMA should be down */
186 mutex_destroy(&priv->hw_lock);
187 kfree(priv);
188
189 return 0;
190}
191
192static void ark3116_init_termios(struct tty_struct *tty)
193{
194 struct ktermios *termios = &tty->termios;
195 *termios = tty_std_termios;
196 termios->c_cflag = B9600 | CS8
197 | CREAD | HUPCL | CLOCAL;
198 termios->c_ispeed = 9600;
199 termios->c_ospeed = 9600;
200}
201
202static void ark3116_set_termios(struct tty_struct *tty,
203 struct usb_serial_port *port,
204 struct ktermios *old_termios)
205{
206 struct usb_serial *serial = port->serial;
207 struct ark3116_private *priv = usb_get_serial_port_data(port);
208 struct ktermios *termios = &tty->termios;
209 unsigned int cflag = termios->c_cflag;
210 int bps = tty_get_baud_rate(tty);
211 int quot;
212 __u8 lcr, hcr, eval;
213
214 /* set data bit count */
215 switch (cflag & CSIZE) {
216 case CS5:
217 lcr = UART_LCR_WLEN5;
218 break;
219 case CS6:
220 lcr = UART_LCR_WLEN6;
221 break;
222 case CS7:
223 lcr = UART_LCR_WLEN7;
224 break;
225 default:
226 case CS8:
227 lcr = UART_LCR_WLEN8;
228 break;
229 }
230 if (cflag & CSTOPB)
231 lcr |= UART_LCR_STOP;
232 if (cflag & PARENB)
233 lcr |= UART_LCR_PARITY;
234 if (!(cflag & PARODD))
235 lcr |= UART_LCR_EPAR;
236#ifdef CMSPAR
237 if (cflag & CMSPAR)
238 lcr |= UART_LCR_SPAR;
239#endif
240 /* handshake control */
241 hcr = (cflag & CRTSCTS) ? 0x03 : 0x00;
242
243 /* calc baudrate */
244 dev_dbg(&port->dev, "%s - setting bps to %d\n", __func__, bps);
245 eval = 0;
246 switch (bps) {
247 case 0:
248 quot = calc_divisor(9600);
249 break;
250 default:
251 if ((bps < 75) || (bps > 3000000))
252 bps = 9600;
253 quot = calc_divisor(bps);
254 break;
255 case 460800:
256 eval = 1;
257 quot = calc_divisor(bps);
258 break;
259 case 921600:
260 eval = 2;
261 quot = calc_divisor(bps);
262 break;
263 }
264
265 /* Update state: synchronize */
266 mutex_lock(&priv->hw_lock);
267
268 /* keep old LCR_SBC bit */
269 lcr |= (priv->lcr & UART_LCR_SBC);
270
271 dev_dbg(&port->dev, "%s - setting hcr:0x%02x,lcr:0x%02x,quot:%d\n",
272 __func__, hcr, lcr, quot);
273
274 /* handshake control */
275 if (priv->hcr != hcr) {
276 priv->hcr = hcr;
277 ark3116_write_reg(serial, 0x8, hcr);
278 }
279
280 /* baudrate */
281 if (priv->quot != quot) {
282 priv->quot = quot;
283 priv->lcr = lcr; /* need to write lcr anyway */
284
285 /* disable DMA since transmit/receive is
286 * shadowed by UART_DLL
287 */
288 ark3116_write_reg(serial, UART_FCR, 0);
289
290 ark3116_write_reg(serial, UART_LCR,
291 lcr|UART_LCR_DLAB);
292 ark3116_write_reg(serial, UART_DLL, quot & 0xff);
293 ark3116_write_reg(serial, UART_DLM, (quot>>8) & 0xff);
294
295 /* restore lcr */
296 ark3116_write_reg(serial, UART_LCR, lcr);
297 /* magic baudrate thingy: not sure what it does,
298 * but windows does this as well.
299 */
300 ark3116_write_reg(serial, 0xe, eval);
301
302 /* enable DMA */
303 ark3116_write_reg(serial, UART_FCR, UART_FCR_DMA_SELECT);
304 } else if (priv->lcr != lcr) {
305 priv->lcr = lcr;
306 ark3116_write_reg(serial, UART_LCR, lcr);
307 }
308
309 mutex_unlock(&priv->hw_lock);
310
311 /* check for software flow control */
312 if (I_IXOFF(tty) || I_IXON(tty)) {
313 dev_warn(&port->dev,
314 "software flow control not implemented\n");
315 }
316
317 /* Don't rewrite B0 */
318 if (tty_termios_baud_rate(termios))
319 tty_termios_encode_baud_rate(termios, bps, bps);
320}
321
322static void ark3116_close(struct usb_serial_port *port)
323{
324 struct usb_serial *serial = port->serial;
325
326 /* disable DMA */
327 ark3116_write_reg(serial, UART_FCR, 0);
328
329 /* deactivate interrupts */
330 ark3116_write_reg(serial, UART_IER, 0);
331
332 usb_serial_generic_close(port);
333
334 usb_kill_urb(port->interrupt_in_urb);
335}
336
337static int ark3116_open(struct tty_struct *tty, struct usb_serial_port *port)
338{
339 struct ark3116_private *priv = usb_get_serial_port_data(port);
340 struct usb_serial *serial = port->serial;
341 unsigned char *buf;
342 int result;
343
344 buf = kmalloc(1, GFP_KERNEL);
345 if (buf == NULL)
346 return -ENOMEM;
347
348 result = usb_serial_generic_open(tty, port);
349 if (result) {
350 dev_dbg(&port->dev,
351 "%s - usb_serial_generic_open failed: %d\n",
352 __func__, result);
353 goto err_free;
354 }
355
356 /* remove any data still left: also clears error state */
357 ark3116_read_reg(serial, UART_RX, buf);
358
359 /* read modem status */
360 result = ark3116_read_reg(serial, UART_MSR, buf);
361 if (result)
362 goto err_close;
363 priv->msr = *buf;
364
365 /* read line status */
366 result = ark3116_read_reg(serial, UART_LSR, buf);
367 if (result)
368 goto err_close;
369 priv->lsr = *buf;
370
371 result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
372 if (result) {
373 dev_err(&port->dev, "submit irq_in urb failed %d\n",
374 result);
375 goto err_close;
376 }
377
378 /* activate interrupts */
379 ark3116_write_reg(port->serial, UART_IER, UART_IER_MSI|UART_IER_RLSI);
380
381 /* enable DMA */
382 ark3116_write_reg(port->serial, UART_FCR, UART_FCR_DMA_SELECT);
383
384 /* setup termios */
385 if (tty)
386 ark3116_set_termios(tty, port, NULL);
387
388 kfree(buf);
389
390 return 0;
391
392err_close:
393 usb_serial_generic_close(port);
394err_free:
395 kfree(buf);
396
397 return result;
398}
399
400static int ark3116_get_serial_info(struct usb_serial_port *port,
401 struct serial_struct __user *retinfo)
402{
403 struct serial_struct tmp;
404
405 memset(&tmp, 0, sizeof(tmp));
406
407 tmp.type = PORT_16654;
408 tmp.line = port->minor;
409 tmp.port = port->port_number;
410 tmp.baud_base = 460800;
411
412 if (copy_to_user(retinfo, &tmp, sizeof(tmp)))
413 return -EFAULT;
414
415 return 0;
416}
417
418static int ark3116_ioctl(struct tty_struct *tty,
419 unsigned int cmd, unsigned long arg)
420{
421 struct usb_serial_port *port = tty->driver_data;
422 void __user *user_arg = (void __user *)arg;
423
424 switch (cmd) {
425 case TIOCGSERIAL:
426 return ark3116_get_serial_info(port, user_arg);
427 default:
428 break;
429 }
430
431 return -ENOIOCTLCMD;
432}
433
434static int ark3116_tiocmget(struct tty_struct *tty)
435{
436 struct usb_serial_port *port = tty->driver_data;
437 struct ark3116_private *priv = usb_get_serial_port_data(port);
438 __u32 status;
439 __u32 ctrl;
440 unsigned long flags;
441
442 mutex_lock(&priv->hw_lock);
443 ctrl = priv->mcr;
444 mutex_unlock(&priv->hw_lock);
445
446 spin_lock_irqsave(&priv->status_lock, flags);
447 status = priv->msr;
448 spin_unlock_irqrestore(&priv->status_lock, flags);
449
450 return (status & UART_MSR_DSR ? TIOCM_DSR : 0) |
451 (status & UART_MSR_CTS ? TIOCM_CTS : 0) |
452 (status & UART_MSR_RI ? TIOCM_RI : 0) |
453 (status & UART_MSR_DCD ? TIOCM_CD : 0) |
454 (ctrl & UART_MCR_DTR ? TIOCM_DTR : 0) |
455 (ctrl & UART_MCR_RTS ? TIOCM_RTS : 0) |
456 (ctrl & UART_MCR_OUT1 ? TIOCM_OUT1 : 0) |
457 (ctrl & UART_MCR_OUT2 ? TIOCM_OUT2 : 0);
458}
459
460static int ark3116_tiocmset(struct tty_struct *tty,
461 unsigned set, unsigned clr)
462{
463 struct usb_serial_port *port = tty->driver_data;
464 struct ark3116_private *priv = usb_get_serial_port_data(port);
465
466 /* we need to take the mutex here, to make sure that the value
467 * in priv->mcr is actually the one that is in the hardware
468 */
469
470 mutex_lock(&priv->hw_lock);
471
472 if (set & TIOCM_RTS)
473 priv->mcr |= UART_MCR_RTS;
474 if (set & TIOCM_DTR)
475 priv->mcr |= UART_MCR_DTR;
476 if (set & TIOCM_OUT1)
477 priv->mcr |= UART_MCR_OUT1;
478 if (set & TIOCM_OUT2)
479 priv->mcr |= UART_MCR_OUT2;
480 if (clr & TIOCM_RTS)
481 priv->mcr &= ~UART_MCR_RTS;
482 if (clr & TIOCM_DTR)
483 priv->mcr &= ~UART_MCR_DTR;
484 if (clr & TIOCM_OUT1)
485 priv->mcr &= ~UART_MCR_OUT1;
486 if (clr & TIOCM_OUT2)
487 priv->mcr &= ~UART_MCR_OUT2;
488
489 ark3116_write_reg(port->serial, UART_MCR, priv->mcr);
490
491 mutex_unlock(&priv->hw_lock);
492
493 return 0;
494}
495
496static void ark3116_break_ctl(struct tty_struct *tty, int break_state)
497{
498 struct usb_serial_port *port = tty->driver_data;
499 struct ark3116_private *priv = usb_get_serial_port_data(port);
500
501 /* LCR is also used for other things: protect access */
502 mutex_lock(&priv->hw_lock);
503
504 if (break_state)
505 priv->lcr |= UART_LCR_SBC;
506 else
507 priv->lcr &= ~UART_LCR_SBC;
508
509 ark3116_write_reg(port->serial, UART_LCR, priv->lcr);
510
511 mutex_unlock(&priv->hw_lock);
512}
513
514static void ark3116_update_msr(struct usb_serial_port *port, __u8 msr)
515{
516 struct ark3116_private *priv = usb_get_serial_port_data(port);
517 unsigned long flags;
518
519 spin_lock_irqsave(&priv->status_lock, flags);
520 priv->msr = msr;
521 spin_unlock_irqrestore(&priv->status_lock, flags);
522
523 if (msr & UART_MSR_ANY_DELTA) {
524 /* update input line counters */
525 if (msr & UART_MSR_DCTS)
526 port->icount.cts++;
527 if (msr & UART_MSR_DDSR)
528 port->icount.dsr++;
529 if (msr & UART_MSR_DDCD)
530 port->icount.dcd++;
531 if (msr & UART_MSR_TERI)
532 port->icount.rng++;
533 wake_up_interruptible(&port->port.delta_msr_wait);
534 }
535}
536
537static void ark3116_update_lsr(struct usb_serial_port *port, __u8 lsr)
538{
539 struct ark3116_private *priv = usb_get_serial_port_data(port);
540 unsigned long flags;
541
542 spin_lock_irqsave(&priv->status_lock, flags);
543 /* combine bits */
544 priv->lsr |= lsr;
545 spin_unlock_irqrestore(&priv->status_lock, flags);
546
547 if (lsr&UART_LSR_BRK_ERROR_BITS) {
548 if (lsr & UART_LSR_BI)
549 port->icount.brk++;
550 if (lsr & UART_LSR_FE)
551 port->icount.frame++;
552 if (lsr & UART_LSR_PE)
553 port->icount.parity++;
554 if (lsr & UART_LSR_OE)
555 port->icount.overrun++;
556 }
557}
558
559static void ark3116_read_int_callback(struct urb *urb)
560{
561 struct usb_serial_port *port = urb->context;
562 int status = urb->status;
563 const __u8 *data = urb->transfer_buffer;
564 int result;
565
566 switch (status) {
567 case -ECONNRESET:
568 case -ENOENT:
569 case -ESHUTDOWN:
570 /* this urb is terminated, clean up */
571 dev_dbg(&port->dev, "%s - urb shutting down with status: %d\n",
572 __func__, status);
573 return;
574 default:
575 dev_dbg(&port->dev, "%s - nonzero urb status received: %d\n",
576 __func__, status);
577 break;
578 case 0: /* success */
579 /* discovered this by trail and error... */
580 if ((urb->actual_length == 4) && (data[0] == 0xe8)) {
581 const __u8 id = data[1]&UART_IIR_ID;
582 dev_dbg(&port->dev, "%s: iir=%02x\n", __func__, data[1]);
583 if (id == UART_IIR_MSI) {
584 dev_dbg(&port->dev, "%s: msr=%02x\n",
585 __func__, data[3]);
586 ark3116_update_msr(port, data[3]);
587 break;
588 } else if (id == UART_IIR_RLSI) {
589 dev_dbg(&port->dev, "%s: lsr=%02x\n",
590 __func__, data[2]);
591 ark3116_update_lsr(port, data[2]);
592 break;
593 }
594 }
595 /*
596 * Not sure what this data meant...
597 */
598 usb_serial_debug_data(&port->dev, __func__,
599 urb->actual_length,
600 urb->transfer_buffer);
601 break;
602 }
603
604 result = usb_submit_urb(urb, GFP_ATOMIC);
605 if (result)
606 dev_err(&port->dev, "failed to resubmit interrupt urb: %d\n",
607 result);
608}
609
610
611/* Data comes in via the bulk (data) URB, errors/interrupts via the int URB.
612 * This means that we cannot be sure which data byte has an associated error
613 * condition, so we report an error for all data in the next bulk read.
614 *
615 * Actually, there might even be a window between the bulk data leaving the
616 * ark and reading/resetting the lsr in the read_bulk_callback where an
617 * interrupt for the next data block could come in.
618 * Without somekind of ordering on the ark, we would have to report the
619 * error for the next block of data as well...
620 * For now, let's pretend this can't happen.
621 */
622static void ark3116_process_read_urb(struct urb *urb)
623{
624 struct usb_serial_port *port = urb->context;
625 struct ark3116_private *priv = usb_get_serial_port_data(port);
626 unsigned char *data = urb->transfer_buffer;
627 char tty_flag = TTY_NORMAL;
628 unsigned long flags;
629 __u32 lsr;
630
631 /* update line status */
632 spin_lock_irqsave(&priv->status_lock, flags);
633 lsr = priv->lsr;
634 priv->lsr &= ~UART_LSR_BRK_ERROR_BITS;
635 spin_unlock_irqrestore(&priv->status_lock, flags);
636
637 if (!urb->actual_length)
638 return;
639
640 if (lsr & UART_LSR_BRK_ERROR_BITS) {
641 if (lsr & UART_LSR_BI)
642 tty_flag = TTY_BREAK;
643 else if (lsr & UART_LSR_PE)
644 tty_flag = TTY_PARITY;
645 else if (lsr & UART_LSR_FE)
646 tty_flag = TTY_FRAME;
647
648 /* overrun is special, not associated with a char */
649 if (lsr & UART_LSR_OE)
650 tty_insert_flip_char(&port->port, 0, TTY_OVERRUN);
651 }
652 tty_insert_flip_string_fixed_flag(&port->port, data, tty_flag,
653 urb->actual_length);
654 tty_flip_buffer_push(&port->port);
655}
656
657static struct usb_serial_driver ark3116_device = {
658 .driver = {
659 .owner = THIS_MODULE,
660 .name = "ark3116",
661 },
662 .id_table = id_table,
663 .num_ports = 1,
664 .num_bulk_in = 1,
665 .num_bulk_out = 1,
666 .num_interrupt_in = 1,
667 .port_probe = ark3116_port_probe,
668 .port_remove = ark3116_port_remove,
669 .set_termios = ark3116_set_termios,
670 .init_termios = ark3116_init_termios,
671 .ioctl = ark3116_ioctl,
672 .tiocmget = ark3116_tiocmget,
673 .tiocmset = ark3116_tiocmset,
674 .tiocmiwait = usb_serial_generic_tiocmiwait,
675 .get_icount = usb_serial_generic_get_icount,
676 .open = ark3116_open,
677 .close = ark3116_close,
678 .break_ctl = ark3116_break_ctl,
679 .read_int_callback = ark3116_read_int_callback,
680 .process_read_urb = ark3116_process_read_urb,
681};
682
683static struct usb_serial_driver * const serial_drivers[] = {
684 &ark3116_device, NULL
685};
686
687module_usb_serial_driver(serial_drivers, id_table);
688
689MODULE_LICENSE("GPL");
690
691MODULE_AUTHOR(DRIVER_AUTHOR);
692MODULE_DESCRIPTION(DRIVER_DESC);
693
694/*
695 * The following describes what I learned from studying the old
696 * ark3116.c driver, disassembling the windows driver, and some lucky
697 * guesses. Since I do not have any datasheet or other
698 * documentation, inaccuracies are almost guaranteed.
699 *
700 * Some specs for the ARK3116 can be found here:
701 * http://web.archive.org/web/20060318000438/
702 * www.arkmicro.com/en/products/view.php?id=10
703 * On that page, 2 GPIO pins are mentioned: I assume these are the
704 * OUT1 and OUT2 pins of the UART, so I added support for those
705 * through the MCR. Since the pins are not available on my hardware,
706 * I could not verify this.
707 * Also, it states there is "on-chip hardware flow control". I have
708 * discovered how to enable that. Unfortunately, I do not know how to
709 * enable XON/XOFF (software) flow control, which would need support
710 * from the chip as well to work. Because of the wording on the web
711 * page there is a real possibility the chip simply does not support
712 * software flow control.
713 *
714 * I got my ark3116 as part of a mobile phone adapter cable. On the
715 * PCB, the following numbered contacts are present:
716 *
717 * 1:- +5V
718 * 2:o DTR
719 * 3:i RX
720 * 4:i DCD
721 * 5:o RTS
722 * 6:o TX
723 * 7:i RI
724 * 8:i DSR
725 * 10:- 0V
726 * 11:i CTS
727 *
728 * On my chip, all signals seem to be 3.3V, but 5V tolerant. But that
729 * may be different for the one you have ;-).
730 *
731 * The windows driver limits the registers to 0-F, so I assume there
732 * are actually 16 present on the device.
733 *
734 * On an UART interrupt, 4 bytes of data come in on the interrupt
735 * endpoint. The bytes are 0xe8 IIR LSR MSR.
736 *
737 * The baudrate seems to be generated from the 12MHz crystal, using
738 * 4-times subsampling. So quot=12e6/(4*baud). Also see description
739 * of register E.
740 *
741 * Registers 0-7:
742 * These seem to be the same as for a regular 16450. The FCR is set
743 * to UART_FCR_DMA_SELECT (0x8), I guess to enable transfers between
744 * the UART and the USB bridge/DMA engine.
745 *
746 * Register 8:
747 * By trial and error, I found out that bit 0 enables hardware CTS,
748 * stopping TX when CTS is +5V. Bit 1 does the same for RTS, making
749 * RTS +5V when the 3116 cannot transfer the data to the USB bus
750 * (verified by disabling the reading URB). Note that as far as I can
751 * tell, the windows driver does NOT use this, so there might be some
752 * hardware bug or something.
753 *
754 * According to a patch provided here
755 * (http://lkml.org/lkml/2009/7/26/56), the ARK3116 can also be used
756 * as an IrDA dongle. Since I do not have such a thing, I could not
757 * investigate that aspect. However, I can speculate ;-).
758 *
759 * - IrDA encodes data differently than RS232. Most likely, one of
760 * the bits in registers 9..E enables the IR ENDEC (encoder/decoder).
761 * - Depending on the IR transceiver, the input and output need to be
762 * inverted, so there are probably bits for that as well.
763 * - IrDA is half-duplex, so there should be a bit for selecting that.
764 *
765 * This still leaves at least two registers unaccounted for. Perhaps
766 * The chip can do XON/XOFF or CRC in HW?
767 *
768 * Register 9:
769 * Set to 0x00 for IrDA, when the baudrate is initialised.
770 *
771 * Register A:
772 * Set to 0x01 for IrDA, at init.
773 *
774 * Register B:
775 * Set to 0x01 for IrDA, 0x00 for RS232, at init.
776 *
777 * Register C:
778 * Set to 00 for IrDA, at init.
779 *
780 * Register D:
781 * Set to 0x41 for IrDA, at init.
782 *
783 * Register E:
784 * Somekind of baudrate override. The windows driver seems to set
785 * this to 0x00 for normal baudrates, 0x01 for 460800, 0x02 for 921600.
786 * Since 460800 and 921600 cannot be obtained by dividing 3MHz by an integer,
787 * it could be somekind of subdivisor thingy.
788 * However,it does not seem to do anything: selecting 921600 (divisor 3,
789 * reg E=2), still gets 1 MHz. I also checked if registers 9, C or F would
790 * work, but they don't.
791 *
792 * Register F: unknown
793 */