xref: /openbmc/linux/drivers/usb/serial/ark3116.c (revision baa7eb025ab14f3cba2e35c0a8648f9c9f01d24f)
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/init.h>
27 #include <linux/ioctl.h>
28 #include <linux/tty.h>
29 #include <linux/slab.h>
30 #include <linux/tty_flip.h>
31 #include <linux/module.h>
32 #include <linux/usb.h>
33 #include <linux/usb/serial.h>
34 #include <linux/serial.h>
35 #include <linux/serial_reg.h>
36 #include <linux/uaccess.h>
37 #include <linux/mutex.h>
38 #include <linux/spinlock.h>
39 
40 static int debug;
41 /*
42  * Version information
43  */
44 
45 #define DRIVER_VERSION "v0.6"
46 #define DRIVER_AUTHOR "Bart Hartgers <bart.hartgers+ark3116@gmail.com>"
47 #define DRIVER_DESC "USB ARK3116 serial/IrDA driver"
48 #define DRIVER_DEV_DESC "ARK3116 RS232/IrDA"
49 #define DRIVER_NAME "ark3116"
50 
51 /* usb timeout of 1 second */
52 #define ARK_TIMEOUT (1*HZ)
53 
54 static const struct usb_device_id id_table[] = {
55 	{ USB_DEVICE(0x6547, 0x0232) },
56 	{ USB_DEVICE(0x18ec, 0x3118) },		/* USB to IrDA adapter */
57 	{ },
58 };
59 MODULE_DEVICE_TABLE(usb, id_table);
60 
61 static int is_irda(struct usb_serial *serial)
62 {
63 	struct usb_device *dev = serial->dev;
64 	if (le16_to_cpu(dev->descriptor.idVendor) == 0x18ec &&
65 			le16_to_cpu(dev->descriptor.idProduct) == 0x3118)
66 		return 1;
67 	return 0;
68 }
69 
70 struct ark3116_private {
71 	wait_queue_head_t       delta_msr_wait;
72 	struct async_icount	icount;
73 	int			irda;	/* 1 for irda device */
74 
75 	/* protects hw register updates */
76 	struct mutex		hw_lock;
77 
78 	int			quot;	/* baudrate divisor */
79 	__u32			lcr;	/* line control register value */
80 	__u32			hcr;	/* handshake control register (0x8)
81 					 * value */
82 	__u32			mcr;	/* modem contol register value */
83 
84 	/* protects the status values below */
85 	spinlock_t		status_lock;
86 	__u32			msr;	/* modem status register value */
87 	__u32			lsr;	/* line status register value */
88 };
89 
90 static int ark3116_write_reg(struct usb_serial *serial,
91 			     unsigned reg, __u8 val)
92 {
93 	int result;
94 	 /* 0xfe 0x40 are magic values taken from original driver */
95 	result = usb_control_msg(serial->dev,
96 				 usb_sndctrlpipe(serial->dev, 0),
97 				 0xfe, 0x40, val, reg,
98 				 NULL, 0, ARK_TIMEOUT);
99 	return result;
100 }
101 
102 static int ark3116_read_reg(struct usb_serial *serial,
103 			    unsigned reg, unsigned char *buf)
104 {
105 	int result;
106 	/* 0xfe 0xc0 are magic values taken from original driver */
107 	result = usb_control_msg(serial->dev,
108 				 usb_rcvctrlpipe(serial->dev, 0),
109 				 0xfe, 0xc0, 0, reg,
110 				 buf, 1, ARK_TIMEOUT);
111 	if (result < 0)
112 		return result;
113 	else
114 		return buf[0];
115 }
116 
117 static inline int calc_divisor(int bps)
118 {
119 	/* Original ark3116 made some exceptions in rounding here
120 	 * because windows did the same. Assume that is not really
121 	 * necessary.
122 	 * Crystal is 12MHz, probably because of USB, but we divide by 4?
123 	 */
124 	return (12000000 + 2*bps) / (4*bps);
125 }
126 
127 static int ark3116_attach(struct usb_serial *serial)
128 {
129 	struct usb_serial_port *port = serial->port[0];
130 	struct ark3116_private *priv;
131 
132 	/* make sure we have our end-points */
133 	if ((serial->num_bulk_in == 0) ||
134 	    (serial->num_bulk_out == 0) ||
135 	    (serial->num_interrupt_in == 0)) {
136 		dev_err(&serial->dev->dev,
137 			"%s - missing endpoint - "
138 			"bulk in: %d, bulk out: %d, int in %d\n",
139 			KBUILD_MODNAME,
140 			serial->num_bulk_in,
141 			serial->num_bulk_out,
142 			serial->num_interrupt_in);
143 		return -EINVAL;
144 	}
145 
146 	priv = kzalloc(sizeof(struct ark3116_private),
147 		       GFP_KERNEL);
148 	if (!priv)
149 		return -ENOMEM;
150 
151 	init_waitqueue_head(&priv->delta_msr_wait);
152 	mutex_init(&priv->hw_lock);
153 	spin_lock_init(&priv->status_lock);
154 
155 	priv->irda = is_irda(serial);
156 
157 	usb_set_serial_port_data(port, priv);
158 
159 	/* setup the hardware */
160 	ark3116_write_reg(serial, UART_IER, 0);
161 	/* disable DMA */
162 	ark3116_write_reg(serial, UART_FCR, 0);
163 	/* handshake control */
164 	priv->hcr = 0;
165 	ark3116_write_reg(serial, 0x8     , 0);
166 	/* modem control */
167 	priv->mcr = 0;
168 	ark3116_write_reg(serial, UART_MCR, 0);
169 
170 	if (!(priv->irda)) {
171 		ark3116_write_reg(serial, 0xb , 0);
172 	} else {
173 		ark3116_write_reg(serial, 0xb , 1);
174 		ark3116_write_reg(serial, 0xc , 0);
175 		ark3116_write_reg(serial, 0xd , 0x41);
176 		ark3116_write_reg(serial, 0xa , 1);
177 	}
178 
179 	/* setup baudrate */
180 	ark3116_write_reg(serial, UART_LCR, UART_LCR_DLAB);
181 
182 	/* setup for 9600 8N1 */
183 	priv->quot = calc_divisor(9600);
184 	ark3116_write_reg(serial, UART_DLL, priv->quot & 0xff);
185 	ark3116_write_reg(serial, UART_DLM, (priv->quot>>8) & 0xff);
186 
187 	priv->lcr = UART_LCR_WLEN8;
188 	ark3116_write_reg(serial, UART_LCR, UART_LCR_WLEN8);
189 
190 	ark3116_write_reg(serial, 0xe, 0);
191 
192 	if (priv->irda)
193 		ark3116_write_reg(serial, 0x9, 0);
194 
195 	dev_info(&serial->dev->dev,
196 		"%s using %s mode\n",
197 		KBUILD_MODNAME,
198 		priv->irda ? "IrDA" : "RS232");
199 	return 0;
200 }
201 
202 static void ark3116_release(struct usb_serial *serial)
203 {
204 	struct usb_serial_port *port = serial->port[0];
205 	struct ark3116_private *priv = usb_get_serial_port_data(port);
206 
207 	/* device is closed, so URBs and DMA should be down */
208 
209 	usb_set_serial_port_data(port, NULL);
210 
211 	mutex_destroy(&priv->hw_lock);
212 
213 	kfree(priv);
214 }
215 
216 static void ark3116_init_termios(struct tty_struct *tty)
217 {
218 	struct ktermios *termios = tty->termios;
219 	*termios = tty_std_termios;
220 	termios->c_cflag = B9600 | CS8
221 				      | CREAD | HUPCL | CLOCAL;
222 	termios->c_ispeed = 9600;
223 	termios->c_ospeed = 9600;
224 }
225 
226 static void ark3116_set_termios(struct tty_struct *tty,
227 				struct usb_serial_port *port,
228 				struct ktermios *old_termios)
229 {
230 	struct usb_serial *serial = port->serial;
231 	struct ark3116_private *priv = usb_get_serial_port_data(port);
232 	struct ktermios *termios = tty->termios;
233 	unsigned int cflag = termios->c_cflag;
234 	int bps = tty_get_baud_rate(tty);
235 	int quot;
236 	__u8 lcr, hcr, eval;
237 
238 	/* set data bit count */
239 	switch (cflag & CSIZE) {
240 	case CS5:
241 		lcr = UART_LCR_WLEN5;
242 		break;
243 	case CS6:
244 		lcr = UART_LCR_WLEN6;
245 		break;
246 	case CS7:
247 		lcr = UART_LCR_WLEN7;
248 		break;
249 	default:
250 	case CS8:
251 		lcr = UART_LCR_WLEN8;
252 		break;
253 	}
254 	if (cflag & CSTOPB)
255 		lcr |= UART_LCR_STOP;
256 	if (cflag & PARENB)
257 		lcr |= UART_LCR_PARITY;
258 	if (!(cflag & PARODD))
259 		lcr |= UART_LCR_EPAR;
260 #ifdef CMSPAR
261 	if (cflag & CMSPAR)
262 		lcr |= UART_LCR_SPAR;
263 #endif
264 	/* handshake control */
265 	hcr = (cflag & CRTSCTS) ? 0x03 : 0x00;
266 
267 	/* calc baudrate */
268 	dbg("%s - setting bps to %d", __func__, bps);
269 	eval = 0;
270 	switch (bps) {
271 	case 0:
272 		quot = calc_divisor(9600);
273 		break;
274 	default:
275 		if ((bps < 75) || (bps > 3000000))
276 			bps = 9600;
277 		quot = calc_divisor(bps);
278 		break;
279 	case 460800:
280 		eval = 1;
281 		quot = calc_divisor(bps);
282 		break;
283 	case 921600:
284 		eval = 2;
285 		quot = calc_divisor(bps);
286 		break;
287 	}
288 
289 	/* Update state: synchronize */
290 	mutex_lock(&priv->hw_lock);
291 
292 	/* keep old LCR_SBC bit */
293 	lcr |= (priv->lcr & UART_LCR_SBC);
294 
295 	dbg("%s - setting hcr:0x%02x,lcr:0x%02x,quot:%d",
296 	    __func__, hcr, lcr, quot);
297 
298 	/* handshake control */
299 	if (priv->hcr != hcr) {
300 		priv->hcr = hcr;
301 		ark3116_write_reg(serial, 0x8, hcr);
302 	}
303 
304 	/* baudrate */
305 	if (priv->quot != quot) {
306 		priv->quot = quot;
307 		priv->lcr = lcr; /* need to write lcr anyway */
308 
309 		/* disable DMA since transmit/receive is
310 		 * shadowed by UART_DLL
311 		 */
312 		ark3116_write_reg(serial, UART_FCR, 0);
313 
314 		ark3116_write_reg(serial, UART_LCR,
315 				  lcr|UART_LCR_DLAB);
316 		ark3116_write_reg(serial, UART_DLL, quot & 0xff);
317 		ark3116_write_reg(serial, UART_DLM, (quot>>8) & 0xff);
318 
319 		/* restore lcr */
320 		ark3116_write_reg(serial, UART_LCR, lcr);
321 		/* magic baudrate thingy: not sure what it does,
322 		 * but windows does this as well.
323 		 */
324 		ark3116_write_reg(serial, 0xe, eval);
325 
326 		/* enable DMA */
327 		ark3116_write_reg(serial, UART_FCR, UART_FCR_DMA_SELECT);
328 	} else if (priv->lcr != lcr) {
329 		priv->lcr = lcr;
330 		ark3116_write_reg(serial, UART_LCR, lcr);
331 	}
332 
333 	mutex_unlock(&priv->hw_lock);
334 
335 	/* check for software flow control */
336 	if (I_IXOFF(tty) || I_IXON(tty)) {
337 		dev_warn(&serial->dev->dev,
338 			 "%s: don't know how to do software flow control\n",
339 			 KBUILD_MODNAME);
340 	}
341 
342 	/* Don't rewrite B0 */
343 	if (tty_termios_baud_rate(termios))
344 		tty_termios_encode_baud_rate(termios, bps, bps);
345 }
346 
347 static void ark3116_close(struct usb_serial_port *port)
348 {
349 	struct usb_serial *serial = port->serial;
350 
351 	if (serial->dev) {
352 		/* disable DMA */
353 		ark3116_write_reg(serial, UART_FCR, 0);
354 
355 		/* deactivate interrupts */
356 		ark3116_write_reg(serial, UART_IER, 0);
357 
358 		usb_serial_generic_close(port);
359 		if (serial->num_interrupt_in)
360 			usb_kill_urb(port->interrupt_in_urb);
361 	}
362 
363 }
364 
365 static int ark3116_open(struct tty_struct *tty, struct usb_serial_port *port)
366 {
367 	struct ark3116_private *priv = usb_get_serial_port_data(port);
368 	struct usb_serial *serial = port->serial;
369 	unsigned char *buf;
370 	int result;
371 
372 	buf = kmalloc(1, GFP_KERNEL);
373 	if (buf == NULL)
374 		return -ENOMEM;
375 
376 	result = usb_serial_generic_open(tty, port);
377 	if (result) {
378 		dbg("%s - usb_serial_generic_open failed: %d",
379 		    __func__, result);
380 		goto err_out;
381 	}
382 
383 	/* setup termios */
384 	if (tty)
385 		ark3116_set_termios(tty, port, NULL);
386 
387 	/* remove any data still left: also clears error state */
388 	ark3116_read_reg(serial, UART_RX, buf);
389 
390 	/* read modem status */
391 	priv->msr = ark3116_read_reg(serial, UART_MSR, buf);
392 	/* read line status */
393 	priv->lsr = ark3116_read_reg(serial, UART_LSR, buf);
394 
395 	result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
396 	if (result) {
397 		dev_err(&port->dev, "submit irq_in urb failed %d\n",
398 			result);
399 		ark3116_close(port);
400 		goto err_out;
401 	}
402 
403 	/* activate interrupts */
404 	ark3116_write_reg(port->serial, UART_IER, UART_IER_MSI|UART_IER_RLSI);
405 
406 	/* enable DMA */
407 	ark3116_write_reg(port->serial, UART_FCR, UART_FCR_DMA_SELECT);
408 
409 err_out:
410 	kfree(buf);
411 	return result;
412 }
413 
414 static int ark3116_get_icount(struct tty_struct *tty,
415 					struct serial_icounter_struct *icount)
416 {
417 	struct usb_serial_port *port = tty->driver_data;
418 	struct ark3116_private *priv = usb_get_serial_port_data(port);
419 	struct async_icount cnow = priv->icount;
420 	icount->cts = cnow.cts;
421 	icount->dsr = cnow.dsr;
422 	icount->rng = cnow.rng;
423 	icount->dcd = cnow.dcd;
424 	icount->rx = cnow.rx;
425 	icount->tx = cnow.tx;
426 	icount->frame = cnow.frame;
427 	icount->overrun = cnow.overrun;
428 	icount->parity = cnow.parity;
429 	icount->brk = cnow.brk;
430 	icount->buf_overrun = cnow.buf_overrun;
431 	return 0;
432 }
433 
434 static int ark3116_ioctl(struct tty_struct *tty, struct file *file,
435 			 unsigned int cmd, unsigned long arg)
436 {
437 	struct usb_serial_port *port = tty->driver_data;
438 	struct ark3116_private *priv = usb_get_serial_port_data(port);
439 	struct serial_struct serstruct;
440 	void __user *user_arg = (void __user *)arg;
441 
442 	switch (cmd) {
443 	case TIOCGSERIAL:
444 		/* XXX: Some of these values are probably wrong. */
445 		memset(&serstruct, 0, sizeof(serstruct));
446 		serstruct.type = PORT_16654;
447 		serstruct.line = port->serial->minor;
448 		serstruct.port = port->number;
449 		serstruct.custom_divisor = 0;
450 		serstruct.baud_base = 460800;
451 
452 		if (copy_to_user(user_arg, &serstruct, sizeof(serstruct)))
453 			return -EFAULT;
454 
455 		return 0;
456 	case TIOCSSERIAL:
457 		if (copy_from_user(&serstruct, user_arg, sizeof(serstruct)))
458 			return -EFAULT;
459 		return 0;
460 	case TIOCMIWAIT:
461 		for (;;) {
462 			struct async_icount prev = priv->icount;
463 			interruptible_sleep_on(&priv->delta_msr_wait);
464 			/* see if a signal did it */
465 			if (signal_pending(current))
466 				return -ERESTARTSYS;
467 			if ((prev.rng == priv->icount.rng) &&
468 			    (prev.dsr == priv->icount.dsr) &&
469 			    (prev.dcd == priv->icount.dcd) &&
470 			    (prev.cts == priv->icount.cts))
471 				return -EIO;
472 			if ((arg & TIOCM_RNG &&
473 			     (prev.rng != priv->icount.rng)) ||
474 			    (arg & TIOCM_DSR &&
475 			     (prev.dsr != priv->icount.dsr)) ||
476 			    (arg & TIOCM_CD  &&
477 			     (prev.dcd != priv->icount.dcd)) ||
478 			    (arg & TIOCM_CTS &&
479 			     (prev.cts != priv->icount.cts)))
480 				return 0;
481 		}
482 		break;
483 	}
484 
485 	return -ENOIOCTLCMD;
486 }
487 
488 static int ark3116_tiocmget(struct tty_struct *tty, struct file *file)
489 {
490 	struct usb_serial_port *port = tty->driver_data;
491 	struct ark3116_private *priv = usb_get_serial_port_data(port);
492 	__u32 status;
493 	__u32 ctrl;
494 	unsigned long flags;
495 
496 	mutex_lock(&priv->hw_lock);
497 	ctrl = priv->mcr;
498 	mutex_unlock(&priv->hw_lock);
499 
500 	spin_lock_irqsave(&priv->status_lock, flags);
501 	status = priv->msr;
502 	spin_unlock_irqrestore(&priv->status_lock, flags);
503 
504 	return  (status & UART_MSR_DSR  ? TIOCM_DSR  : 0) |
505 		(status & UART_MSR_CTS  ? TIOCM_CTS  : 0) |
506 		(status & UART_MSR_RI   ? TIOCM_RI   : 0) |
507 		(status & UART_MSR_DCD  ? TIOCM_CD   : 0) |
508 		(ctrl   & UART_MCR_DTR  ? TIOCM_DTR  : 0) |
509 		(ctrl   & UART_MCR_RTS  ? TIOCM_RTS  : 0) |
510 		(ctrl   & UART_MCR_OUT1 ? TIOCM_OUT1 : 0) |
511 		(ctrl   & UART_MCR_OUT2 ? TIOCM_OUT2 : 0);
512 }
513 
514 static int ark3116_tiocmset(struct tty_struct *tty, struct file *file,
515 			unsigned set, unsigned clr)
516 {
517 	struct usb_serial_port *port = tty->driver_data;
518 	struct ark3116_private *priv = usb_get_serial_port_data(port);
519 
520 	/* we need to take the mutex here, to make sure that the value
521 	 * in priv->mcr is actually the one that is in the hardware
522 	 */
523 
524 	mutex_lock(&priv->hw_lock);
525 
526 	if (set & TIOCM_RTS)
527 		priv->mcr |= UART_MCR_RTS;
528 	if (set & TIOCM_DTR)
529 		priv->mcr |= UART_MCR_DTR;
530 	if (set & TIOCM_OUT1)
531 		priv->mcr |= UART_MCR_OUT1;
532 	if (set & TIOCM_OUT2)
533 		priv->mcr |= UART_MCR_OUT2;
534 	if (clr & TIOCM_RTS)
535 		priv->mcr &= ~UART_MCR_RTS;
536 	if (clr & TIOCM_DTR)
537 		priv->mcr &= ~UART_MCR_DTR;
538 	if (clr & TIOCM_OUT1)
539 		priv->mcr &= ~UART_MCR_OUT1;
540 	if (clr & TIOCM_OUT2)
541 		priv->mcr &= ~UART_MCR_OUT2;
542 
543 	ark3116_write_reg(port->serial, UART_MCR, priv->mcr);
544 
545 	mutex_unlock(&priv->hw_lock);
546 
547 	return 0;
548 }
549 
550 static void ark3116_break_ctl(struct tty_struct *tty, int break_state)
551 {
552 	struct usb_serial_port *port = tty->driver_data;
553 	struct ark3116_private *priv = usb_get_serial_port_data(port);
554 
555 	/* LCR is also used for other things: protect access */
556 	mutex_lock(&priv->hw_lock);
557 
558 	if (break_state)
559 		priv->lcr |= UART_LCR_SBC;
560 	else
561 		priv->lcr &= ~UART_LCR_SBC;
562 
563 	ark3116_write_reg(port->serial, UART_LCR, priv->lcr);
564 
565 	mutex_unlock(&priv->hw_lock);
566 }
567 
568 static void ark3116_update_msr(struct usb_serial_port *port, __u8 msr)
569 {
570 	struct ark3116_private *priv = usb_get_serial_port_data(port);
571 	unsigned long flags;
572 
573 	spin_lock_irqsave(&priv->status_lock, flags);
574 	priv->msr = msr;
575 	spin_unlock_irqrestore(&priv->status_lock, flags);
576 
577 	if (msr & UART_MSR_ANY_DELTA) {
578 		/* update input line counters */
579 		if (msr & UART_MSR_DCTS)
580 			priv->icount.cts++;
581 		if (msr & UART_MSR_DDSR)
582 			priv->icount.dsr++;
583 		if (msr & UART_MSR_DDCD)
584 			priv->icount.dcd++;
585 		if (msr & UART_MSR_TERI)
586 			priv->icount.rng++;
587 		wake_up_interruptible(&priv->delta_msr_wait);
588 	}
589 }
590 
591 static void ark3116_update_lsr(struct usb_serial_port *port, __u8 lsr)
592 {
593 	struct ark3116_private *priv = usb_get_serial_port_data(port);
594 	unsigned long flags;
595 
596 	spin_lock_irqsave(&priv->status_lock, flags);
597 	/* combine bits */
598 	priv->lsr |= lsr;
599 	spin_unlock_irqrestore(&priv->status_lock, flags);
600 
601 	if (lsr&UART_LSR_BRK_ERROR_BITS) {
602 		if (lsr & UART_LSR_BI)
603 			priv->icount.brk++;
604 		if (lsr & UART_LSR_FE)
605 			priv->icount.frame++;
606 		if (lsr & UART_LSR_PE)
607 			priv->icount.parity++;
608 		if (lsr & UART_LSR_OE)
609 			priv->icount.overrun++;
610 	}
611 }
612 
613 static void ark3116_read_int_callback(struct urb *urb)
614 {
615 	struct usb_serial_port *port = urb->context;
616 	int status = urb->status;
617 	const __u8 *data = urb->transfer_buffer;
618 	int result;
619 
620 	switch (status) {
621 	case -ECONNRESET:
622 	case -ENOENT:
623 	case -ESHUTDOWN:
624 		/* this urb is terminated, clean up */
625 		dbg("%s - urb shutting down with status: %d",
626 		    __func__, status);
627 		return;
628 	default:
629 		dbg("%s - nonzero urb status received: %d",
630 		    __func__, status);
631 		break;
632 	case 0: /* success */
633 		/* discovered this by trail and error... */
634 		if ((urb->actual_length == 4) && (data[0] == 0xe8)) {
635 			const __u8 id = data[1]&UART_IIR_ID;
636 			dbg("%s: iir=%02x", __func__, data[1]);
637 			if (id == UART_IIR_MSI) {
638 				dbg("%s: msr=%02x", __func__, data[3]);
639 				ark3116_update_msr(port, data[3]);
640 				break;
641 			} else if (id == UART_IIR_RLSI) {
642 				dbg("%s: lsr=%02x", __func__, data[2]);
643 				ark3116_update_lsr(port, data[2]);
644 				break;
645 			}
646 		}
647 		/*
648 		 * Not sure what this data meant...
649 		 */
650 		usb_serial_debug_data(debug, &port->dev,
651 				      __func__,
652 				      urb->actual_length,
653 				      urb->transfer_buffer);
654 		break;
655 	}
656 
657 	result = usb_submit_urb(urb, GFP_ATOMIC);
658 	if (result)
659 		dev_err(&urb->dev->dev,
660 			"%s - Error %d submitting interrupt urb\n",
661 			__func__, result);
662 }
663 
664 
665 /* Data comes in via the bulk (data) URB, erors/interrupts via the int URB.
666  * This means that we cannot be sure which data byte has an associated error
667  * condition, so we report an error for all data in the next bulk read.
668  *
669  * Actually, there might even be a window between the bulk data leaving the
670  * ark and reading/resetting the lsr in the read_bulk_callback where an
671  * interrupt for the next data block could come in.
672  * Without somekind of ordering on the ark, we would have to report the
673  * error for the next block of data as well...
674  * For now, let's pretend this can't happen.
675  */
676 static void ark3116_process_read_urb(struct urb *urb)
677 {
678 	struct usb_serial_port *port = urb->context;
679 	struct ark3116_private *priv = usb_get_serial_port_data(port);
680 	struct tty_struct *tty;
681 	unsigned char *data = urb->transfer_buffer;
682 	char tty_flag = TTY_NORMAL;
683 	unsigned long flags;
684 	__u32 lsr;
685 
686 	/* update line status */
687 	spin_lock_irqsave(&priv->status_lock, flags);
688 	lsr = priv->lsr;
689 	priv->lsr &= ~UART_LSR_BRK_ERROR_BITS;
690 	spin_unlock_irqrestore(&priv->status_lock, flags);
691 
692 	if (!urb->actual_length)
693 		return;
694 
695 	tty = tty_port_tty_get(&port->port);
696 	if (!tty)
697 		return;
698 
699 	if (lsr & UART_LSR_BRK_ERROR_BITS) {
700 		if (lsr & UART_LSR_BI)
701 			tty_flag = TTY_BREAK;
702 		else if (lsr & UART_LSR_PE)
703 			tty_flag = TTY_PARITY;
704 		else if (lsr & UART_LSR_FE)
705 			tty_flag = TTY_FRAME;
706 
707 		/* overrun is special, not associated with a char */
708 		if (lsr & UART_LSR_OE)
709 			tty_insert_flip_char(tty, 0, TTY_OVERRUN);
710 	}
711 	tty_insert_flip_string_fixed_flag(tty, data, tty_flag,
712 							urb->actual_length);
713 	tty_flip_buffer_push(tty);
714 	tty_kref_put(tty);
715 }
716 
717 static struct usb_driver ark3116_driver = {
718 	.name =		"ark3116",
719 	.probe =	usb_serial_probe,
720 	.disconnect =	usb_serial_disconnect,
721 	.id_table =	id_table,
722 	.no_dynamic_id =	1,
723 };
724 
725 static struct usb_serial_driver ark3116_device = {
726 	.driver = {
727 		.owner =	THIS_MODULE,
728 		.name =		"ark3116",
729 	},
730 	.id_table =		id_table,
731 	.usb_driver =		&ark3116_driver,
732 	.num_ports =		1,
733 	.attach =		ark3116_attach,
734 	.release =		ark3116_release,
735 	.set_termios =		ark3116_set_termios,
736 	.init_termios =		ark3116_init_termios,
737 	.ioctl =		ark3116_ioctl,
738 	.tiocmget =		ark3116_tiocmget,
739 	.tiocmset =		ark3116_tiocmset,
740 	.get_icount =		ark3116_get_icount,
741 	.open =			ark3116_open,
742 	.close =		ark3116_close,
743 	.break_ctl = 		ark3116_break_ctl,
744 	.read_int_callback = 	ark3116_read_int_callback,
745 	.process_read_urb =	ark3116_process_read_urb,
746 };
747 
748 static int __init ark3116_init(void)
749 {
750 	int retval;
751 
752 	retval = usb_serial_register(&ark3116_device);
753 	if (retval)
754 		return retval;
755 	retval = usb_register(&ark3116_driver);
756 	if (retval == 0) {
757 		printk(KERN_INFO "%s:"
758 		       DRIVER_VERSION ":"
759 		       DRIVER_DESC "\n",
760 		       KBUILD_MODNAME);
761 	} else
762 		usb_serial_deregister(&ark3116_device);
763 	return retval;
764 }
765 
766 static void __exit ark3116_exit(void)
767 {
768 	usb_deregister(&ark3116_driver);
769 	usb_serial_deregister(&ark3116_device);
770 }
771 
772 module_init(ark3116_init);
773 module_exit(ark3116_exit);
774 MODULE_LICENSE("GPL");
775 
776 MODULE_AUTHOR(DRIVER_AUTHOR);
777 MODULE_DESCRIPTION(DRIVER_DESC);
778 
779 module_param(debug, bool, S_IRUGO | S_IWUSR);
780 MODULE_PARM_DESC(debug, "Enable debug");
781 
782 /*
783  * The following describes what I learned from studying the old
784  * ark3116.c driver, disassembling the windows driver, and some lucky
785  * guesses. Since I do not have any datasheet or other
786  * documentation, inaccuracies are almost guaranteed.
787  *
788  * Some specs for the ARK3116 can be found here:
789  * http://web.archive.org/web/20060318000438/
790  *   www.arkmicro.com/en/products/view.php?id=10
791  * On that page, 2 GPIO pins are mentioned: I assume these are the
792  * OUT1 and OUT2 pins of the UART, so I added support for those
793  * through the MCR. Since the pins are not available on my hardware,
794  * I could not verify this.
795  * Also, it states there is "on-chip hardware flow control". I have
796  * discovered how to enable that. Unfortunately, I do not know how to
797  * enable XON/XOFF (software) flow control, which would need support
798  * from the chip as well to work. Because of the wording on the web
799  * page there is a real possibility the chip simply does not support
800  * software flow control.
801  *
802  * I got my ark3116 as part of a mobile phone adapter cable. On the
803  * PCB, the following numbered contacts are present:
804  *
805  *  1:- +5V
806  *  2:o DTR
807  *  3:i RX
808  *  4:i DCD
809  *  5:o RTS
810  *  6:o TX
811  *  7:i RI
812  *  8:i DSR
813  * 10:- 0V
814  * 11:i CTS
815  *
816  * On my chip, all signals seem to be 3.3V, but 5V tolerant. But that
817  * may be different for the one you have ;-).
818  *
819  * The windows driver limits the registers to 0-F, so I assume there
820  * are actually 16 present on the device.
821  *
822  * On an UART interrupt, 4 bytes of data come in on the interrupt
823  * endpoint. The bytes are 0xe8 IIR LSR MSR.
824  *
825  * The baudrate seems to be generated from the 12MHz crystal, using
826  * 4-times subsampling. So quot=12e6/(4*baud). Also see description
827  * of register E.
828  *
829  * Registers 0-7:
830  * These seem to be the same as for a regular 16450. The FCR is set
831  * to UART_FCR_DMA_SELECT (0x8), I guess to enable transfers between
832  * the UART and the USB bridge/DMA engine.
833  *
834  * Register 8:
835  * By trial and error, I found out that bit 0 enables hardware CTS,
836  * stopping TX when CTS is +5V. Bit 1 does the same for RTS, making
837  * RTS +5V when the 3116 cannot transfer the data to the USB bus
838  * (verified by disabling the reading URB). Note that as far as I can
839  * tell, the windows driver does NOT use this, so there might be some
840  * hardware bug or something.
841  *
842  * According to a patch provided here
843  * (http://lkml.org/lkml/2009/7/26/56), the ARK3116 can also be used
844  * as an IrDA dongle. Since I do not have such a thing, I could not
845  * investigate that aspect. However, I can speculate ;-).
846  *
847  * - IrDA encodes data differently than RS232. Most likely, one of
848  *   the bits in registers 9..E enables the IR ENDEC (encoder/decoder).
849  * - Depending on the IR transceiver, the input and output need to be
850  *   inverted, so there are probably bits for that as well.
851  * - IrDA is half-duplex, so there should be a bit for selecting that.
852  *
853  * This still leaves at least two registers unaccounted for. Perhaps
854  * The chip can do XON/XOFF or CRC in HW?
855  *
856  * Register 9:
857  * Set to 0x00 for IrDA, when the baudrate is initialised.
858  *
859  * Register A:
860  * Set to 0x01 for IrDA, at init.
861  *
862  * Register B:
863  * Set to 0x01 for IrDA, 0x00 for RS232, at init.
864  *
865  * Register C:
866  * Set to 00 for IrDA, at init.
867  *
868  * Register D:
869  * Set to 0x41 for IrDA, at init.
870  *
871  * Register E:
872  * Somekind of baudrate override. The windows driver seems to set
873  * this to 0x00 for normal baudrates, 0x01 for 460800, 0x02 for 921600.
874  * Since 460800 and 921600 cannot be obtained by dividing 3MHz by an integer,
875  * it could be somekind of subdivisor thingy.
876  * However,it does not seem to do anything: selecting 921600 (divisor 3,
877  * reg E=2), still gets 1 MHz. I also checked if registers 9, C or F would
878  * work, but they don't.
879  *
880  * Register F: unknown
881  */
882