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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/*
2 * Copyright (C) 2009 by Bart Hartgers (bart.hartgers+ark3116@gmail.com)
3 * Original version:
4 * Copyright (C) 2006
5 * Simon Schulz (ark3116_driver <at> auctionant.de)
6 *
7 * ark3116
8 * - implements a driver for the arkmicro ark3116 chipset (vendor=0x6547,
9 * productid=0x0232) (used in a datacable called KQ-U8A)
10 *
11 * Supports full modem status lines, break, hardware flow control. Does not
12 * support software flow control, since I do not know how to enable it in hw.
13 *
14 * This driver is a essentially new implementation. I initially dug
15 * into the old ark3116.c driver and suddenly realized the ark3116 is
16 * a 16450 with a USB interface glued to it. See comments at the
17 * bottom of this file.
18 *
19 * This program is free software; you can redistribute it and/or modify it
20 * under the terms of the GNU General Public License as published by the
21 * Free Software Foundation; either version 2 of the License, or (at your
22 * option) any later version.
23 */
24
25#include <linux/kernel.h>
26#include <linux/ioctl.h>
27#include <linux/tty.h>
28#include <linux/slab.h>
29#include <linux/tty_flip.h>
30#include <linux/module.h>
31#include <linux/usb.h>
32#include <linux/usb/serial.h>
33#include <linux/serial.h>
34#include <linux/serial_reg.h>
35#include <linux/uaccess.h>
36#include <linux/mutex.h>
37#include <linux/spinlock.h>
38
39#define DRIVER_AUTHOR "Bart Hartgers <bart.hartgers+ark3116@gmail.com>"
40#define DRIVER_DESC "USB ARK3116 serial/IrDA driver"
41#define DRIVER_DEV_DESC "ARK3116 RS232/IrDA"
42#define DRIVER_NAME "ark3116"
43
44/* usb timeout of 1 second */
45#define ARK_TIMEOUT 1000
46
47static const struct usb_device_id id_table[] = {
48 { USB_DEVICE(0x6547, 0x0232) },
49 { USB_DEVICE(0x18ec, 0x3118) }, /* USB to IrDA adapter */
50 { },
51};
52MODULE_DEVICE_TABLE(usb, id_table);
53
54static int is_irda(struct usb_serial *serial)
55{
56 struct usb_device *dev = serial->dev;
57 if (le16_to_cpu(dev->descriptor.idVendor) == 0x18ec &&
58 le16_to_cpu(dev->descriptor.idProduct) == 0x3118)
59 return 1;
60 return 0;
61}
62
63struct ark3116_private {
64 int irda; /* 1 for irda device */
65
66 /* protects hw register updates */
67 struct mutex hw_lock;
68
69 int quot; /* baudrate divisor */
70 __u32 lcr; /* line control register value */
71 __u32 hcr; /* handshake control register (0x8)
72 * value */
73 __u32 mcr; /* modem control register value */
74
75 /* protects the status values below */
76 spinlock_t status_lock;
77 __u32 msr; /* modem status register value */
78 __u32 lsr; /* line status register value */
79};
80
81static int ark3116_write_reg(struct usb_serial *serial,
82 unsigned reg, __u8 val)
83{
84 int result;
85 /* 0xfe 0x40 are magic values taken from original driver */
86 result = usb_control_msg(serial->dev,
87 usb_sndctrlpipe(serial->dev, 0),
88 0xfe, 0x40, val, reg,
89 NULL, 0, ARK_TIMEOUT);
90 return result;
91}
92
93static int ark3116_read_reg(struct usb_serial *serial,
94 unsigned reg, unsigned char *buf)
95{
96 int result;
97 /* 0xfe 0xc0 are magic values taken from original driver */
98 result = usb_control_msg(serial->dev,
99 usb_rcvctrlpipe(serial->dev, 0),
100 0xfe, 0xc0, 0, reg,
101 buf, 1, ARK_TIMEOUT);
102 if (result < 1) {
103 dev_err(&serial->interface->dev,
104 "failed to read register %u: %d\n",
105 reg, result);
106 if (result >= 0)
107 result = -EIO;
108
109 return result;
110 }
111
112 return buf[0];
113}
114
115static inline int calc_divisor(int bps)
116{
117 /* Original ark3116 made some exceptions in rounding here
118 * because windows did the same. Assume that is not really
119 * necessary.
120 * Crystal is 12MHz, probably because of USB, but we divide by 4?
121 */
122 return (12000000 + 2*bps) / (4*bps);
123}
124
125static int ark3116_attach(struct usb_serial *serial)
126{
127 /* make sure we have our end-points */
128 if ((serial->num_bulk_in == 0) ||
129 (serial->num_bulk_out == 0) ||
130 (serial->num_interrupt_in == 0)) {
131 dev_err(&serial->dev->dev,
132 "%s - missing endpoint - "
133 "bulk in: %d, bulk out: %d, int in %d\n",
134 KBUILD_MODNAME,
135 serial->num_bulk_in,
136 serial->num_bulk_out,
137 serial->num_interrupt_in);
138 return -EINVAL;
139 }
140
141 return 0;
142}
143
144static int ark3116_port_probe(struct usb_serial_port *port)
145{
146 struct usb_serial *serial = port->serial;
147 struct ark3116_private *priv;
148
149 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
150 if (!priv)
151 return -ENOMEM;
152
153 mutex_init(&priv->hw_lock);
154 spin_lock_init(&priv->status_lock);
155
156 priv->irda = is_irda(serial);
157
158 usb_set_serial_port_data(port, priv);
159
160 /* setup the hardware */
161 ark3116_write_reg(serial, UART_IER, 0);
162 /* disable DMA */
163 ark3116_write_reg(serial, UART_FCR, 0);
164 /* handshake control */
165 priv->hcr = 0;
166 ark3116_write_reg(serial, 0x8 , 0);
167 /* modem control */
168 priv->mcr = 0;
169 ark3116_write_reg(serial, UART_MCR, 0);
170
171 if (!(priv->irda)) {
172 ark3116_write_reg(serial, 0xb , 0);
173 } else {
174 ark3116_write_reg(serial, 0xb , 1);
175 ark3116_write_reg(serial, 0xc , 0);
176 ark3116_write_reg(serial, 0xd , 0x41);
177 ark3116_write_reg(serial, 0xa , 1);
178 }
179
180 /* setup baudrate */
181 ark3116_write_reg(serial, UART_LCR, UART_LCR_DLAB);
182
183 /* setup for 9600 8N1 */
184 priv->quot = calc_divisor(9600);
185 ark3116_write_reg(serial, UART_DLL, priv->quot & 0xff);
186 ark3116_write_reg(serial, UART_DLM, (priv->quot>>8) & 0xff);
187
188 priv->lcr = UART_LCR_WLEN8;
189 ark3116_write_reg(serial, UART_LCR, UART_LCR_WLEN8);
190
191 ark3116_write_reg(serial, 0xe, 0);
192
193 if (priv->irda)
194 ark3116_write_reg(serial, 0x9, 0);
195
196 dev_info(&serial->dev->dev,
197 "%s using %s mode\n",
198 KBUILD_MODNAME,
199 priv->irda ? "IrDA" : "RS232");
200 return 0;
201}
202
203static int ark3116_port_remove(struct usb_serial_port *port)
204{
205 struct ark3116_private *priv = usb_get_serial_port_data(port);
206
207 /* device is closed, so URBs and DMA should be down */
208 mutex_destroy(&priv->hw_lock);
209 kfree(priv);
210
211 return 0;
212}
213
214static void ark3116_init_termios(struct tty_struct *tty)
215{
216 struct ktermios *termios = &tty->termios;
217 *termios = tty_std_termios;
218 termios->c_cflag = B9600 | CS8
219 | CREAD | HUPCL | CLOCAL;
220 termios->c_ispeed = 9600;
221 termios->c_ospeed = 9600;
222}
223
224static void ark3116_set_termios(struct tty_struct *tty,
225 struct usb_serial_port *port,
226 struct ktermios *old_termios)
227{
228 struct usb_serial *serial = port->serial;
229 struct ark3116_private *priv = usb_get_serial_port_data(port);
230 struct ktermios *termios = &tty->termios;
231 unsigned int cflag = termios->c_cflag;
232 int bps = tty_get_baud_rate(tty);
233 int quot;
234 __u8 lcr, hcr, eval;
235
236 /* set data bit count */
237 switch (cflag & CSIZE) {
238 case CS5:
239 lcr = UART_LCR_WLEN5;
240 break;
241 case CS6:
242 lcr = UART_LCR_WLEN6;
243 break;
244 case CS7:
245 lcr = UART_LCR_WLEN7;
246 break;
247 default:
248 case CS8:
249 lcr = UART_LCR_WLEN8;
250 break;
251 }
252 if (cflag & CSTOPB)
253 lcr |= UART_LCR_STOP;
254 if (cflag & PARENB)
255 lcr |= UART_LCR_PARITY;
256 if (!(cflag & PARODD))
257 lcr |= UART_LCR_EPAR;
258#ifdef CMSPAR
259 if (cflag & CMSPAR)
260 lcr |= UART_LCR_SPAR;
261#endif
262 /* handshake control */
263 hcr = (cflag & CRTSCTS) ? 0x03 : 0x00;
264
265 /* calc baudrate */
266 dev_dbg(&port->dev, "%s - setting bps to %d\n", __func__, bps);
267 eval = 0;
268 switch (bps) {
269 case 0:
270 quot = calc_divisor(9600);
271 break;
272 default:
273 if ((bps < 75) || (bps > 3000000))
274 bps = 9600;
275 quot = calc_divisor(bps);
276 break;
277 case 460800:
278 eval = 1;
279 quot = calc_divisor(bps);
280 break;
281 case 921600:
282 eval = 2;
283 quot = calc_divisor(bps);
284 break;
285 }
286
287 /* Update state: synchronize */
288 mutex_lock(&priv->hw_lock);
289
290 /* keep old LCR_SBC bit */
291 lcr |= (priv->lcr & UART_LCR_SBC);
292
293 dev_dbg(&port->dev, "%s - setting hcr:0x%02x,lcr:0x%02x,quot:%d\n",
294 __func__, hcr, lcr, quot);
295
296 /* handshake control */
297 if (priv->hcr != hcr) {
298 priv->hcr = hcr;
299 ark3116_write_reg(serial, 0x8, hcr);
300 }
301
302 /* baudrate */
303 if (priv->quot != quot) {
304 priv->quot = quot;
305 priv->lcr = lcr; /* need to write lcr anyway */
306
307 /* disable DMA since transmit/receive is
308 * shadowed by UART_DLL
309 */
310 ark3116_write_reg(serial, UART_FCR, 0);
311
312 ark3116_write_reg(serial, UART_LCR,
313 lcr|UART_LCR_DLAB);
314 ark3116_write_reg(serial, UART_DLL, quot & 0xff);
315 ark3116_write_reg(serial, UART_DLM, (quot>>8) & 0xff);
316
317 /* restore lcr */
318 ark3116_write_reg(serial, UART_LCR, lcr);
319 /* magic baudrate thingy: not sure what it does,
320 * but windows does this as well.
321 */
322 ark3116_write_reg(serial, 0xe, eval);
323
324 /* enable DMA */
325 ark3116_write_reg(serial, UART_FCR, UART_FCR_DMA_SELECT);
326 } else if (priv->lcr != lcr) {
327 priv->lcr = lcr;
328 ark3116_write_reg(serial, UART_LCR, lcr);
329 }
330
331 mutex_unlock(&priv->hw_lock);
332
333 /* check for software flow control */
334 if (I_IXOFF(tty) || I_IXON(tty)) {
335 dev_warn(&serial->dev->dev,
336 "%s: don't know how to do software flow control\n",
337 KBUILD_MODNAME);
338 }
339
340 /* Don't rewrite B0 */
341 if (tty_termios_baud_rate(termios))
342 tty_termios_encode_baud_rate(termios, bps, bps);
343}
344
345static void ark3116_close(struct usb_serial_port *port)
346{
347 struct usb_serial *serial = port->serial;
348
349 /* disable DMA */
350 ark3116_write_reg(serial, UART_FCR, 0);
351
352 /* deactivate interrupts */
353 ark3116_write_reg(serial, UART_IER, 0);
354
355 usb_serial_generic_close(port);
356 if (serial->num_interrupt_in)
357 usb_kill_urb(port->interrupt_in_urb);
358}
359
360static int ark3116_open(struct tty_struct *tty, struct usb_serial_port *port)
361{
362 struct ark3116_private *priv = usb_get_serial_port_data(port);
363 struct usb_serial *serial = port->serial;
364 unsigned char *buf;
365 int result;
366
367 buf = kmalloc(1, GFP_KERNEL);
368 if (buf == NULL)
369 return -ENOMEM;
370
371 result = usb_serial_generic_open(tty, port);
372 if (result) {
373 dev_dbg(&port->dev,
374 "%s - usb_serial_generic_open failed: %d\n",
375 __func__, result);
376 goto err_out;
377 }
378
379 /* remove any data still left: also clears error state */
380 ark3116_read_reg(serial, UART_RX, buf);
381
382 /* read modem status */
383 priv->msr = ark3116_read_reg(serial, UART_MSR, buf);
384 /* read line status */
385 priv->lsr = ark3116_read_reg(serial, UART_LSR, buf);
386
387 result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
388 if (result) {
389 dev_err(&port->dev, "submit irq_in urb failed %d\n",
390 result);
391 ark3116_close(port);
392 goto err_out;
393 }
394
395 /* activate interrupts */
396 ark3116_write_reg(port->serial, UART_IER, UART_IER_MSI|UART_IER_RLSI);
397
398 /* enable DMA */
399 ark3116_write_reg(port->serial, UART_FCR, UART_FCR_DMA_SELECT);
400
401 /* setup termios */
402 if (tty)
403 ark3116_set_termios(tty, port, NULL);
404
405err_out:
406 kfree(buf);
407 return result;
408}
409
410static int ark3116_ioctl(struct tty_struct *tty,
411 unsigned int cmd, unsigned long arg)
412{
413 struct usb_serial_port *port = tty->driver_data;
414 struct serial_struct serstruct;
415 void __user *user_arg = (void __user *)arg;
416
417 switch (cmd) {
418 case TIOCGSERIAL:
419 /* XXX: Some of these values are probably wrong. */
420 memset(&serstruct, 0, sizeof(serstruct));
421 serstruct.type = PORT_16654;
422 serstruct.line = port->minor;
423 serstruct.port = port->port_number;
424 serstruct.custom_divisor = 0;
425 serstruct.baud_base = 460800;
426
427 if (copy_to_user(user_arg, &serstruct, sizeof(serstruct)))
428 return -EFAULT;
429
430 return 0;
431 case TIOCSSERIAL:
432 if (copy_from_user(&serstruct, user_arg, sizeof(serstruct)))
433 return -EFAULT;
434 return 0;
435 }
436
437 return -ENOIOCTLCMD;
438}
439
440static int ark3116_tiocmget(struct tty_struct *tty)
441{
442 struct usb_serial_port *port = tty->driver_data;
443 struct ark3116_private *priv = usb_get_serial_port_data(port);
444 __u32 status;
445 __u32 ctrl;
446 unsigned long flags;
447
448 mutex_lock(&priv->hw_lock);
449 ctrl = priv->mcr;
450 mutex_unlock(&priv->hw_lock);
451
452 spin_lock_irqsave(&priv->status_lock, flags);
453 status = priv->msr;
454 spin_unlock_irqrestore(&priv->status_lock, flags);
455
456 return (status & UART_MSR_DSR ? TIOCM_DSR : 0) |
457 (status & UART_MSR_CTS ? TIOCM_CTS : 0) |
458 (status & UART_MSR_RI ? TIOCM_RI : 0) |
459 (status & UART_MSR_DCD ? TIOCM_CD : 0) |
460 (ctrl & UART_MCR_DTR ? TIOCM_DTR : 0) |
461 (ctrl & UART_MCR_RTS ? TIOCM_RTS : 0) |
462 (ctrl & UART_MCR_OUT1 ? TIOCM_OUT1 : 0) |
463 (ctrl & UART_MCR_OUT2 ? TIOCM_OUT2 : 0);
464}
465
466static int ark3116_tiocmset(struct tty_struct *tty,
467 unsigned set, unsigned clr)
468{
469 struct usb_serial_port *port = tty->driver_data;
470 struct ark3116_private *priv = usb_get_serial_port_data(port);
471
472 /* we need to take the mutex here, to make sure that the value
473 * in priv->mcr is actually the one that is in the hardware
474 */
475
476 mutex_lock(&priv->hw_lock);
477
478 if (set & TIOCM_RTS)
479 priv->mcr |= UART_MCR_RTS;
480 if (set & TIOCM_DTR)
481 priv->mcr |= UART_MCR_DTR;
482 if (set & TIOCM_OUT1)
483 priv->mcr |= UART_MCR_OUT1;
484 if (set & TIOCM_OUT2)
485 priv->mcr |= UART_MCR_OUT2;
486 if (clr & TIOCM_RTS)
487 priv->mcr &= ~UART_MCR_RTS;
488 if (clr & TIOCM_DTR)
489 priv->mcr &= ~UART_MCR_DTR;
490 if (clr & TIOCM_OUT1)
491 priv->mcr &= ~UART_MCR_OUT1;
492 if (clr & TIOCM_OUT2)
493 priv->mcr &= ~UART_MCR_OUT2;
494
495 ark3116_write_reg(port->serial, UART_MCR, priv->mcr);
496
497 mutex_unlock(&priv->hw_lock);
498
499 return 0;
500}
501
502static void ark3116_break_ctl(struct tty_struct *tty, int break_state)
503{
504 struct usb_serial_port *port = tty->driver_data;
505 struct ark3116_private *priv = usb_get_serial_port_data(port);
506
507 /* LCR is also used for other things: protect access */
508 mutex_lock(&priv->hw_lock);
509
510 if (break_state)
511 priv->lcr |= UART_LCR_SBC;
512 else
513 priv->lcr &= ~UART_LCR_SBC;
514
515 ark3116_write_reg(port->serial, UART_LCR, priv->lcr);
516
517 mutex_unlock(&priv->hw_lock);
518}
519
520static void ark3116_update_msr(struct usb_serial_port *port, __u8 msr)
521{
522 struct ark3116_private *priv = usb_get_serial_port_data(port);
523 unsigned long flags;
524
525 spin_lock_irqsave(&priv->status_lock, flags);
526 priv->msr = msr;
527 spin_unlock_irqrestore(&priv->status_lock, flags);
528
529 if (msr & UART_MSR_ANY_DELTA) {
530 /* update input line counters */
531 if (msr & UART_MSR_DCTS)
532 port->icount.cts++;
533 if (msr & UART_MSR_DDSR)
534 port->icount.dsr++;
535 if (msr & UART_MSR_DDCD)
536 port->icount.dcd++;
537 if (msr & UART_MSR_TERI)
538 port->icount.rng++;
539 wake_up_interruptible(&port->port.delta_msr_wait);
540 }
541}
542
543static void ark3116_update_lsr(struct usb_serial_port *port, __u8 lsr)
544{
545 struct ark3116_private *priv = usb_get_serial_port_data(port);
546 unsigned long flags;
547
548 spin_lock_irqsave(&priv->status_lock, flags);
549 /* combine bits */
550 priv->lsr |= lsr;
551 spin_unlock_irqrestore(&priv->status_lock, flags);
552
553 if (lsr&UART_LSR_BRK_ERROR_BITS) {
554 if (lsr & UART_LSR_BI)
555 port->icount.brk++;
556 if (lsr & UART_LSR_FE)
557 port->icount.frame++;
558 if (lsr & UART_LSR_PE)
559 port->icount.parity++;
560 if (lsr & UART_LSR_OE)
561 port->icount.overrun++;
562 }
563}
564
565static void ark3116_read_int_callback(struct urb *urb)
566{
567 struct usb_serial_port *port = urb->context;
568 int status = urb->status;
569 const __u8 *data = urb->transfer_buffer;
570 int result;
571
572 switch (status) {
573 case -ECONNRESET:
574 case -ENOENT:
575 case -ESHUTDOWN:
576 /* this urb is terminated, clean up */
577 dev_dbg(&port->dev, "%s - urb shutting down with status: %d\n",
578 __func__, status);
579 return;
580 default:
581 dev_dbg(&port->dev, "%s - nonzero urb status received: %d\n",
582 __func__, status);
583 break;
584 case 0: /* success */
585 /* discovered this by trail and error... */
586 if ((urb->actual_length == 4) && (data[0] == 0xe8)) {
587 const __u8 id = data[1]&UART_IIR_ID;
588 dev_dbg(&port->dev, "%s: iir=%02x\n", __func__, data[1]);
589 if (id == UART_IIR_MSI) {
590 dev_dbg(&port->dev, "%s: msr=%02x\n",
591 __func__, data[3]);
592 ark3116_update_msr(port, data[3]);
593 break;
594 } else if (id == UART_IIR_RLSI) {
595 dev_dbg(&port->dev, "%s: lsr=%02x\n",
596 __func__, data[2]);
597 ark3116_update_lsr(port, data[2]);
598 break;
599 }
600 }
601 /*
602 * Not sure what this data meant...
603 */
604 usb_serial_debug_data(&port->dev, __func__,
605 urb->actual_length,
606 urb->transfer_buffer);
607 break;
608 }
609
610 result = usb_submit_urb(urb, GFP_ATOMIC);
611 if (result)
612 dev_err(&urb->dev->dev,
613 "%s - Error %d submitting interrupt urb\n",
614 __func__, result);
615}
616
617
618/* Data comes in via the bulk (data) URB, errors/interrupts via the int URB.
619 * This means that we cannot be sure which data byte has an associated error
620 * condition, so we report an error for all data in the next bulk read.
621 *
622 * Actually, there might even be a window between the bulk data leaving the
623 * ark and reading/resetting the lsr in the read_bulk_callback where an
624 * interrupt for the next data block could come in.
625 * Without somekind of ordering on the ark, we would have to report the
626 * error for the next block of data as well...
627 * For now, let's pretend this can't happen.
628 */
629static void ark3116_process_read_urb(struct urb *urb)
630{
631 struct usb_serial_port *port = urb->context;
632 struct ark3116_private *priv = usb_get_serial_port_data(port);
633 unsigned char *data = urb->transfer_buffer;
634 char tty_flag = TTY_NORMAL;
635 unsigned long flags;
636 __u32 lsr;
637
638 /* update line status */
639 spin_lock_irqsave(&priv->status_lock, flags);
640 lsr = priv->lsr;
641 priv->lsr &= ~UART_LSR_BRK_ERROR_BITS;
642 spin_unlock_irqrestore(&priv->status_lock, flags);
643
644 if (!urb->actual_length)
645 return;
646
647 if (lsr & UART_LSR_BRK_ERROR_BITS) {
648 if (lsr & UART_LSR_BI)
649 tty_flag = TTY_BREAK;
650 else if (lsr & UART_LSR_PE)
651 tty_flag = TTY_PARITY;
652 else if (lsr & UART_LSR_FE)
653 tty_flag = TTY_FRAME;
654
655 /* overrun is special, not associated with a char */
656 if (lsr & UART_LSR_OE)
657 tty_insert_flip_char(&port->port, 0, TTY_OVERRUN);
658 }
659 tty_insert_flip_string_fixed_flag(&port->port, data, tty_flag,
660 urb->actual_length);
661 tty_flip_buffer_push(&port->port);
662}
663
664static struct usb_serial_driver ark3116_device = {
665 .driver = {
666 .owner = THIS_MODULE,
667 .name = "ark3116",
668 },
669 .id_table = id_table,
670 .num_ports = 1,
671 .attach = ark3116_attach,
672 .port_probe = ark3116_port_probe,
673 .port_remove = ark3116_port_remove,
674 .set_termios = ark3116_set_termios,
675 .init_termios = ark3116_init_termios,
676 .ioctl = ark3116_ioctl,
677 .tiocmget = ark3116_tiocmget,
678 .tiocmset = ark3116_tiocmset,
679 .tiocmiwait = usb_serial_generic_tiocmiwait,
680 .get_icount = usb_serial_generic_get_icount,
681 .open = ark3116_open,
682 .close = ark3116_close,
683 .break_ctl = ark3116_break_ctl,
684 .read_int_callback = ark3116_read_int_callback,
685 .process_read_urb = ark3116_process_read_urb,
686};
687
688static struct usb_serial_driver * const serial_drivers[] = {
689 &ark3116_device, NULL
690};
691
692module_usb_serial_driver(serial_drivers, id_table);
693
694MODULE_LICENSE("GPL");
695
696MODULE_AUTHOR(DRIVER_AUTHOR);
697MODULE_DESCRIPTION(DRIVER_DESC);
698
699/*
700 * The following describes what I learned from studying the old
701 * ark3116.c driver, disassembling the windows driver, and some lucky
702 * guesses. Since I do not have any datasheet or other
703 * documentation, inaccuracies are almost guaranteed.
704 *
705 * Some specs for the ARK3116 can be found here:
706 * http://web.archive.org/web/20060318000438/
707 * www.arkmicro.com/en/products/view.php?id=10
708 * On that page, 2 GPIO pins are mentioned: I assume these are the
709 * OUT1 and OUT2 pins of the UART, so I added support for those
710 * through the MCR. Since the pins are not available on my hardware,
711 * I could not verify this.
712 * Also, it states there is "on-chip hardware flow control". I have
713 * discovered how to enable that. Unfortunately, I do not know how to
714 * enable XON/XOFF (software) flow control, which would need support
715 * from the chip as well to work. Because of the wording on the web
716 * page there is a real possibility the chip simply does not support
717 * software flow control.
718 *
719 * I got my ark3116 as part of a mobile phone adapter cable. On the
720 * PCB, the following numbered contacts are present:
721 *
722 * 1:- +5V
723 * 2:o DTR
724 * 3:i RX
725 * 4:i DCD
726 * 5:o RTS
727 * 6:o TX
728 * 7:i RI
729 * 8:i DSR
730 * 10:- 0V
731 * 11:i CTS
732 *
733 * On my chip, all signals seem to be 3.3V, but 5V tolerant. But that
734 * may be different for the one you have ;-).
735 *
736 * The windows driver limits the registers to 0-F, so I assume there
737 * are actually 16 present on the device.
738 *
739 * On an UART interrupt, 4 bytes of data come in on the interrupt
740 * endpoint. The bytes are 0xe8 IIR LSR MSR.
741 *
742 * The baudrate seems to be generated from the 12MHz crystal, using
743 * 4-times subsampling. So quot=12e6/(4*baud). Also see description
744 * of register E.
745 *
746 * Registers 0-7:
747 * These seem to be the same as for a regular 16450. The FCR is set
748 * to UART_FCR_DMA_SELECT (0x8), I guess to enable transfers between
749 * the UART and the USB bridge/DMA engine.
750 *
751 * Register 8:
752 * By trial and error, I found out that bit 0 enables hardware CTS,
753 * stopping TX when CTS is +5V. Bit 1 does the same for RTS, making
754 * RTS +5V when the 3116 cannot transfer the data to the USB bus
755 * (verified by disabling the reading URB). Note that as far as I can
756 * tell, the windows driver does NOT use this, so there might be some
757 * hardware bug or something.
758 *
759 * According to a patch provided here
760 * (http://lkml.org/lkml/2009/7/26/56), the ARK3116 can also be used
761 * as an IrDA dongle. Since I do not have such a thing, I could not
762 * investigate that aspect. However, I can speculate ;-).
763 *
764 * - IrDA encodes data differently than RS232. Most likely, one of
765 * the bits in registers 9..E enables the IR ENDEC (encoder/decoder).
766 * - Depending on the IR transceiver, the input and output need to be
767 * inverted, so there are probably bits for that as well.
768 * - IrDA is half-duplex, so there should be a bit for selecting that.
769 *
770 * This still leaves at least two registers unaccounted for. Perhaps
771 * The chip can do XON/XOFF or CRC in HW?
772 *
773 * Register 9:
774 * Set to 0x00 for IrDA, when the baudrate is initialised.
775 *
776 * Register A:
777 * Set to 0x01 for IrDA, at init.
778 *
779 * Register B:
780 * Set to 0x01 for IrDA, 0x00 for RS232, at init.
781 *
782 * Register C:
783 * Set to 00 for IrDA, at init.
784 *
785 * Register D:
786 * Set to 0x41 for IrDA, at init.
787 *
788 * Register E:
789 * Somekind of baudrate override. The windows driver seems to set
790 * this to 0x00 for normal baudrates, 0x01 for 460800, 0x02 for 921600.
791 * Since 460800 and 921600 cannot be obtained by dividing 3MHz by an integer,
792 * it could be somekind of subdivisor thingy.
793 * However,it does not seem to do anything: selecting 921600 (divisor 3,
794 * reg E=2), still gets 1 MHz. I also checked if registers 9, C or F would
795 * work, but they don't.
796 *
797 * Register F: unknown
798 */