xref: /linux/drivers/usb/serial/oti6858.c (revision 8f668fbbd571bbd5187a9a0eae150b768fc388ac)
1 /*
2  * Ours Technology Inc. OTi-6858 USB to serial adapter driver.
3  *
4  * Copyleft  (C) 2007 Kees Lemmens (adapted for kernel 2.6.20)
5  * Copyright (C) 2006 Tomasz Michal Lukaszewski (FIXME: add e-mail)
6  * Copyright (C) 2001-2004 Greg Kroah-Hartman (greg@kroah.com)
7  * Copyright (C) 2003 IBM Corp.
8  *
9  * Many thanks to the authors of pl2303 driver: all functions in this file
10  * are heavily based on pl2303 code, buffering code is a 1-to-1 copy.
11  *
12  * Warning! You use this driver on your own risk! The only official
13  * description of this device I have is datasheet from manufacturer,
14  * and it doesn't contain almost any information needed to write a driver.
15  * Almost all knowlegde used while writing this driver was gathered by:
16  *  - analyzing traffic between device and the M$ Windows 2000 driver,
17  *  - trying different bit combinations and checking pin states
18  *    with a voltmeter,
19  *  - receiving malformed frames and producing buffer overflows
20  *    to learn how errors are reported,
21  * So, THIS CODE CAN DESTROY OTi-6858 AND ANY OTHER DEVICES, THAT ARE
22  * CONNECTED TO IT!
23  *
24  * This program is free software; you can redistribute it and/or modify
25  * it under the terms of the GNU General Public License as published by
26  * the Free Software Foundation; either version 2 of the License.
27  *
28  * See Documentation/usb/usb-serial.txt for more information on using this
29  * driver
30  *
31  * TODO:
32  *  - implement correct flushing for ioctls and oti6858_close()
33  *  - check how errors (rx overflow, parity error, framing error) are reported
34  *  - implement oti6858_break_ctl()
35  *  - implement more ioctls
36  *  - test/implement flow control
37  *  - allow setting custom baud rates
38  */
39 
40 #include <linux/kernel.h>
41 #include <linux/errno.h>
42 #include <linux/init.h>
43 #include <linux/slab.h>
44 #include <linux/tty.h>
45 #include <linux/tty_driver.h>
46 #include <linux/tty_flip.h>
47 #include <linux/serial.h>
48 #include <linux/module.h>
49 #include <linux/moduleparam.h>
50 #include <linux/spinlock.h>
51 #include <linux/usb.h>
52 #include <linux/usb/serial.h>
53 #include <linux/uaccess.h>
54 #include <linux/kfifo.h>
55 #include "oti6858.h"
56 
57 #define OTI6858_DESCRIPTION \
58 	"Ours Technology Inc. OTi-6858 USB to serial adapter driver"
59 #define OTI6858_AUTHOR "Tomasz Michal Lukaszewski <FIXME@FIXME>"
60 
61 static const struct usb_device_id id_table[] = {
62 	{ USB_DEVICE(OTI6858_VENDOR_ID, OTI6858_PRODUCT_ID) },
63 	{ }
64 };
65 
66 MODULE_DEVICE_TABLE(usb, id_table);
67 
68 /* requests */
69 #define	OTI6858_REQ_GET_STATUS		(USB_DIR_IN | USB_TYPE_VENDOR | 0x00)
70 #define	OTI6858_REQ_T_GET_STATUS	0x01
71 
72 #define	OTI6858_REQ_SET_LINE		(USB_DIR_OUT | USB_TYPE_VENDOR | 0x00)
73 #define	OTI6858_REQ_T_SET_LINE		0x00
74 
75 #define	OTI6858_REQ_CHECK_TXBUFF	(USB_DIR_IN | USB_TYPE_VENDOR | 0x01)
76 #define	OTI6858_REQ_T_CHECK_TXBUFF	0x00
77 
78 /* format of the control packet */
79 struct oti6858_control_pkt {
80 	__le16	divisor;	/* baud rate = 96000000 / (16 * divisor), LE */
81 #define OTI6858_MAX_BAUD_RATE	3000000
82 	u8	frame_fmt;
83 #define FMT_STOP_BITS_MASK	0xc0
84 #define FMT_STOP_BITS_1		0x00
85 #define FMT_STOP_BITS_2		0x40	/* 1.5 stop bits if FMT_DATA_BITS_5 */
86 #define FMT_PARITY_MASK		0x38
87 #define FMT_PARITY_NONE		0x00
88 #define FMT_PARITY_ODD		0x08
89 #define FMT_PARITY_EVEN		0x18
90 #define FMT_PARITY_MARK		0x28
91 #define FMT_PARITY_SPACE	0x38
92 #define FMT_DATA_BITS_MASK	0x03
93 #define FMT_DATA_BITS_5		0x00
94 #define FMT_DATA_BITS_6		0x01
95 #define FMT_DATA_BITS_7		0x02
96 #define FMT_DATA_BITS_8		0x03
97 	u8	something;	/* always equals 0x43 */
98 	u8	control;	/* settings of flow control lines */
99 #define CONTROL_MASK		0x0c
100 #define CONTROL_DTR_HIGH	0x08
101 #define CONTROL_RTS_HIGH	0x04
102 	u8	tx_status;
103 #define	TX_BUFFER_EMPTIED	0x09
104 	u8	pin_state;
105 #define PIN_MASK		0x3f
106 #define PIN_MSR_MASK		0x1b
107 #define PIN_RTS			0x20	/* output pin */
108 #define PIN_CTS			0x10	/* input pin, active low */
109 #define PIN_DSR			0x08	/* input pin, active low */
110 #define PIN_DTR			0x04	/* output pin */
111 #define PIN_RI			0x02	/* input pin, active low */
112 #define PIN_DCD			0x01	/* input pin, active low */
113 	u8	rx_bytes_avail;		/* number of bytes in rx buffer */;
114 };
115 
116 #define OTI6858_CTRL_PKT_SIZE	sizeof(struct oti6858_control_pkt)
117 #define OTI6858_CTRL_EQUALS_PENDING(a, priv) \
118 	(((a)->divisor == (priv)->pending_setup.divisor) \
119 	  && ((a)->control == (priv)->pending_setup.control) \
120 	  && ((a)->frame_fmt == (priv)->pending_setup.frame_fmt))
121 
122 /* function prototypes */
123 static int oti6858_open(struct tty_struct *tty, struct usb_serial_port *port);
124 static void oti6858_close(struct usb_serial_port *port);
125 static void oti6858_set_termios(struct tty_struct *tty,
126 			struct usb_serial_port *port, struct ktermios *old);
127 static void oti6858_init_termios(struct tty_struct *tty);
128 static void oti6858_read_int_callback(struct urb *urb);
129 static void oti6858_read_bulk_callback(struct urb *urb);
130 static void oti6858_write_bulk_callback(struct urb *urb);
131 static int oti6858_write(struct tty_struct *tty, struct usb_serial_port *port,
132 			const unsigned char *buf, int count);
133 static int oti6858_write_room(struct tty_struct *tty);
134 static int oti6858_chars_in_buffer(struct tty_struct *tty);
135 static int oti6858_tiocmget(struct tty_struct *tty);
136 static int oti6858_tiocmset(struct tty_struct *tty,
137 				unsigned int set, unsigned int clear);
138 static int oti6858_port_probe(struct usb_serial_port *port);
139 static int oti6858_port_remove(struct usb_serial_port *port);
140 
141 /* device info */
142 static struct usb_serial_driver oti6858_device = {
143 	.driver = {
144 		.owner =	THIS_MODULE,
145 		.name =		"oti6858",
146 	},
147 	.id_table =		id_table,
148 	.num_ports =		1,
149 	.open =			oti6858_open,
150 	.close =		oti6858_close,
151 	.write =		oti6858_write,
152 	.set_termios =		oti6858_set_termios,
153 	.init_termios = 	oti6858_init_termios,
154 	.tiocmget =		oti6858_tiocmget,
155 	.tiocmset =		oti6858_tiocmset,
156 	.tiocmiwait =		usb_serial_generic_tiocmiwait,
157 	.read_bulk_callback =	oti6858_read_bulk_callback,
158 	.read_int_callback =	oti6858_read_int_callback,
159 	.write_bulk_callback =	oti6858_write_bulk_callback,
160 	.write_room =		oti6858_write_room,
161 	.chars_in_buffer =	oti6858_chars_in_buffer,
162 	.port_probe =		oti6858_port_probe,
163 	.port_remove =		oti6858_port_remove,
164 };
165 
166 static struct usb_serial_driver * const serial_drivers[] = {
167 	&oti6858_device, NULL
168 };
169 
170 struct oti6858_private {
171 	spinlock_t lock;
172 
173 	struct oti6858_control_pkt status;
174 
175 	struct {
176 		u8 read_urb_in_use;
177 		u8 write_urb_in_use;
178 	} flags;
179 	struct delayed_work delayed_write_work;
180 
181 	struct {
182 		__le16 divisor;
183 		u8 frame_fmt;
184 		u8 control;
185 	} pending_setup;
186 	u8 transient;
187 	u8 setup_done;
188 	struct delayed_work delayed_setup_work;
189 
190 	struct usb_serial_port *port;   /* USB port with which associated */
191 };
192 
193 static void setup_line(struct work_struct *work)
194 {
195 	struct oti6858_private *priv = container_of(work,
196 			struct oti6858_private, delayed_setup_work.work);
197 	struct usb_serial_port *port = priv->port;
198 	struct oti6858_control_pkt *new_setup;
199 	unsigned long flags;
200 	int result;
201 
202 	new_setup = kmalloc(OTI6858_CTRL_PKT_SIZE, GFP_KERNEL);
203 	if (!new_setup) {
204 		/* we will try again */
205 		schedule_delayed_work(&priv->delayed_setup_work,
206 						msecs_to_jiffies(2));
207 		return;
208 	}
209 
210 	result = usb_control_msg(port->serial->dev,
211 				usb_rcvctrlpipe(port->serial->dev, 0),
212 				OTI6858_REQ_T_GET_STATUS,
213 				OTI6858_REQ_GET_STATUS,
214 				0, 0,
215 				new_setup, OTI6858_CTRL_PKT_SIZE,
216 				100);
217 
218 	if (result != OTI6858_CTRL_PKT_SIZE) {
219 		dev_err(&port->dev, "%s(): error reading status\n", __func__);
220 		kfree(new_setup);
221 		/* we will try again */
222 		schedule_delayed_work(&priv->delayed_setup_work,
223 							msecs_to_jiffies(2));
224 		return;
225 	}
226 
227 	spin_lock_irqsave(&priv->lock, flags);
228 	if (!OTI6858_CTRL_EQUALS_PENDING(new_setup, priv)) {
229 		new_setup->divisor = priv->pending_setup.divisor;
230 		new_setup->control = priv->pending_setup.control;
231 		new_setup->frame_fmt = priv->pending_setup.frame_fmt;
232 
233 		spin_unlock_irqrestore(&priv->lock, flags);
234 		result = usb_control_msg(port->serial->dev,
235 					usb_sndctrlpipe(port->serial->dev, 0),
236 					OTI6858_REQ_T_SET_LINE,
237 					OTI6858_REQ_SET_LINE,
238 					0, 0,
239 					new_setup, OTI6858_CTRL_PKT_SIZE,
240 					100);
241 	} else {
242 		spin_unlock_irqrestore(&priv->lock, flags);
243 		result = 0;
244 	}
245 	kfree(new_setup);
246 
247 	spin_lock_irqsave(&priv->lock, flags);
248 	if (result != OTI6858_CTRL_PKT_SIZE)
249 		priv->transient = 0;
250 	priv->setup_done = 1;
251 	spin_unlock_irqrestore(&priv->lock, flags);
252 
253 	dev_dbg(&port->dev, "%s(): submitting interrupt urb\n", __func__);
254 	result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
255 	if (result != 0) {
256 		dev_err(&port->dev, "%s(): usb_submit_urb() failed with error %d\n",
257 			__func__, result);
258 	}
259 }
260 
261 static void send_data(struct work_struct *work)
262 {
263 	struct oti6858_private *priv = container_of(work,
264 			struct oti6858_private, delayed_write_work.work);
265 	struct usb_serial_port *port = priv->port;
266 	int count = 0, result;
267 	unsigned long flags;
268 	u8 *allow;
269 
270 	spin_lock_irqsave(&priv->lock, flags);
271 	if (priv->flags.write_urb_in_use) {
272 		spin_unlock_irqrestore(&priv->lock, flags);
273 		schedule_delayed_work(&priv->delayed_write_work,
274 						msecs_to_jiffies(2));
275 		return;
276 	}
277 	priv->flags.write_urb_in_use = 1;
278 	spin_unlock_irqrestore(&priv->lock, flags);
279 
280 	spin_lock_irqsave(&port->lock, flags);
281 	count = kfifo_len(&port->write_fifo);
282 	spin_unlock_irqrestore(&port->lock, flags);
283 
284 	if (count > port->bulk_out_size)
285 		count = port->bulk_out_size;
286 
287 	if (count != 0) {
288 		allow = kmalloc(1, GFP_KERNEL);
289 		if (!allow)
290 			return;
291 
292 		result = usb_control_msg(port->serial->dev,
293 				usb_rcvctrlpipe(port->serial->dev, 0),
294 				OTI6858_REQ_T_CHECK_TXBUFF,
295 				OTI6858_REQ_CHECK_TXBUFF,
296 				count, 0, allow, 1, 100);
297 		if (result != 1 || *allow != 0)
298 			count = 0;
299 		kfree(allow);
300 	}
301 
302 	if (count == 0) {
303 		priv->flags.write_urb_in_use = 0;
304 
305 		dev_dbg(&port->dev, "%s(): submitting interrupt urb\n", __func__);
306 		result = usb_submit_urb(port->interrupt_in_urb, GFP_NOIO);
307 		if (result != 0) {
308 			dev_err(&port->dev, "%s(): usb_submit_urb() failed with error %d\n",
309 				__func__, result);
310 		}
311 		return;
312 	}
313 
314 	count = kfifo_out_locked(&port->write_fifo,
315 					port->write_urb->transfer_buffer,
316 					count, &port->lock);
317 	port->write_urb->transfer_buffer_length = count;
318 	result = usb_submit_urb(port->write_urb, GFP_NOIO);
319 	if (result != 0) {
320 		dev_err_console(port, "%s(): usb_submit_urb() failed with error %d\n",
321 				__func__, result);
322 		priv->flags.write_urb_in_use = 0;
323 	}
324 
325 	usb_serial_port_softint(port);
326 }
327 
328 static int oti6858_port_probe(struct usb_serial_port *port)
329 {
330 	struct oti6858_private *priv;
331 
332 	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
333 	if (!priv)
334 		return -ENOMEM;
335 
336 	spin_lock_init(&priv->lock);
337 	priv->port = port;
338 	INIT_DELAYED_WORK(&priv->delayed_setup_work, setup_line);
339 	INIT_DELAYED_WORK(&priv->delayed_write_work, send_data);
340 
341 	usb_set_serial_port_data(port, priv);
342 
343 	port->port.drain_delay = 256;	/* FIXME: check the FIFO length */
344 
345 	return 0;
346 }
347 
348 static int oti6858_port_remove(struct usb_serial_port *port)
349 {
350 	struct oti6858_private *priv;
351 
352 	priv = usb_get_serial_port_data(port);
353 	kfree(priv);
354 
355 	return 0;
356 }
357 
358 static int oti6858_write(struct tty_struct *tty, struct usb_serial_port *port,
359 			const unsigned char *buf, int count)
360 {
361 	if (!count)
362 		return count;
363 
364 	count = kfifo_in_locked(&port->write_fifo, buf, count, &port->lock);
365 
366 	return count;
367 }
368 
369 static int oti6858_write_room(struct tty_struct *tty)
370 {
371 	struct usb_serial_port *port = tty->driver_data;
372 	int room = 0;
373 	unsigned long flags;
374 
375 	spin_lock_irqsave(&port->lock, flags);
376 	room = kfifo_avail(&port->write_fifo);
377 	spin_unlock_irqrestore(&port->lock, flags);
378 
379 	return room;
380 }
381 
382 static int oti6858_chars_in_buffer(struct tty_struct *tty)
383 {
384 	struct usb_serial_port *port = tty->driver_data;
385 	int chars = 0;
386 	unsigned long flags;
387 
388 	spin_lock_irqsave(&port->lock, flags);
389 	chars = kfifo_len(&port->write_fifo);
390 	spin_unlock_irqrestore(&port->lock, flags);
391 
392 	return chars;
393 }
394 
395 static void oti6858_init_termios(struct tty_struct *tty)
396 {
397 	tty->termios = tty_std_termios;
398 	tty->termios.c_cflag = B38400 | CS8 | CREAD | HUPCL | CLOCAL;
399 	tty->termios.c_ispeed = 38400;
400 	tty->termios.c_ospeed = 38400;
401 }
402 
403 static void oti6858_set_termios(struct tty_struct *tty,
404 		struct usb_serial_port *port, struct ktermios *old_termios)
405 {
406 	struct oti6858_private *priv = usb_get_serial_port_data(port);
407 	unsigned long flags;
408 	unsigned int cflag;
409 	u8 frame_fmt, control;
410 	__le16 divisor;
411 	int br;
412 
413 	cflag = tty->termios.c_cflag;
414 
415 	spin_lock_irqsave(&priv->lock, flags);
416 	divisor = priv->pending_setup.divisor;
417 	frame_fmt = priv->pending_setup.frame_fmt;
418 	control = priv->pending_setup.control;
419 	spin_unlock_irqrestore(&priv->lock, flags);
420 
421 	frame_fmt &= ~FMT_DATA_BITS_MASK;
422 	switch (cflag & CSIZE) {
423 	case CS5:
424 		frame_fmt |= FMT_DATA_BITS_5;
425 		break;
426 	case CS6:
427 		frame_fmt |= FMT_DATA_BITS_6;
428 		break;
429 	case CS7:
430 		frame_fmt |= FMT_DATA_BITS_7;
431 		break;
432 	default:
433 	case CS8:
434 		frame_fmt |= FMT_DATA_BITS_8;
435 		break;
436 	}
437 
438 	/* manufacturer claims that this device can work with baud rates
439 	 * up to 3 Mbps; I've tested it only on 115200 bps, so I can't
440 	 * guarantee that any other baud rate will work (especially
441 	 * the higher ones)
442 	 */
443 	br = tty_get_baud_rate(tty);
444 	if (br == 0) {
445 		divisor = 0;
446 	} else {
447 		int real_br;
448 		int new_divisor;
449 		br = min(br, OTI6858_MAX_BAUD_RATE);
450 
451 		new_divisor = (96000000 + 8 * br) / (16 * br);
452 		real_br = 96000000 / (16 * new_divisor);
453 		divisor = cpu_to_le16(new_divisor);
454 		tty_encode_baud_rate(tty, real_br, real_br);
455 	}
456 
457 	frame_fmt &= ~FMT_STOP_BITS_MASK;
458 	if ((cflag & CSTOPB) != 0)
459 		frame_fmt |= FMT_STOP_BITS_2;
460 	else
461 		frame_fmt |= FMT_STOP_BITS_1;
462 
463 	frame_fmt &= ~FMT_PARITY_MASK;
464 	if ((cflag & PARENB) != 0) {
465 		if ((cflag & PARODD) != 0)
466 			frame_fmt |= FMT_PARITY_ODD;
467 		else
468 			frame_fmt |= FMT_PARITY_EVEN;
469 	} else {
470 		frame_fmt |= FMT_PARITY_NONE;
471 	}
472 
473 	control &= ~CONTROL_MASK;
474 	if ((cflag & CRTSCTS) != 0)
475 		control |= (CONTROL_DTR_HIGH | CONTROL_RTS_HIGH);
476 
477 	/* change control lines if we are switching to or from B0 */
478 	/* FIXME:
479 	spin_lock_irqsave(&priv->lock, flags);
480 	control = priv->line_control;
481 	if ((cflag & CBAUD) == B0)
482 		priv->line_control &= ~(CONTROL_DTR | CONTROL_RTS);
483 	else
484 		priv->line_control |= (CONTROL_DTR | CONTROL_RTS);
485 	if (control != priv->line_control) {
486 		control = priv->line_control;
487 		spin_unlock_irqrestore(&priv->lock, flags);
488 		set_control_lines(serial->dev, control);
489 	} else {
490 		spin_unlock_irqrestore(&priv->lock, flags);
491 	}
492 	*/
493 
494 	spin_lock_irqsave(&priv->lock, flags);
495 	if (divisor != priv->pending_setup.divisor
496 			|| control != priv->pending_setup.control
497 			|| frame_fmt != priv->pending_setup.frame_fmt) {
498 		priv->pending_setup.divisor = divisor;
499 		priv->pending_setup.control = control;
500 		priv->pending_setup.frame_fmt = frame_fmt;
501 	}
502 	spin_unlock_irqrestore(&priv->lock, flags);
503 }
504 
505 static int oti6858_open(struct tty_struct *tty, struct usb_serial_port *port)
506 {
507 	struct oti6858_private *priv = usb_get_serial_port_data(port);
508 	struct usb_serial *serial = port->serial;
509 	struct oti6858_control_pkt *buf;
510 	unsigned long flags;
511 	int result;
512 
513 	usb_clear_halt(serial->dev, port->write_urb->pipe);
514 	usb_clear_halt(serial->dev, port->read_urb->pipe);
515 
516 	buf = kmalloc(OTI6858_CTRL_PKT_SIZE, GFP_KERNEL);
517 	if (!buf)
518 		return -ENOMEM;
519 
520 	result = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
521 				OTI6858_REQ_T_GET_STATUS,
522 				OTI6858_REQ_GET_STATUS,
523 				0, 0,
524 				buf, OTI6858_CTRL_PKT_SIZE,
525 				100);
526 	if (result != OTI6858_CTRL_PKT_SIZE) {
527 		/* assume default (after power-on reset) values */
528 		buf->divisor = cpu_to_le16(0x009c);	/* 38400 bps */
529 		buf->frame_fmt = 0x03;	/* 8N1 */
530 		buf->something = 0x43;
531 		buf->control = 0x4c;	/* DTR, RTS */
532 		buf->tx_status = 0x00;
533 		buf->pin_state = 0x5b;	/* RTS, CTS, DSR, DTR, RI, DCD */
534 		buf->rx_bytes_avail = 0x00;
535 	}
536 
537 	spin_lock_irqsave(&priv->lock, flags);
538 	memcpy(&priv->status, buf, OTI6858_CTRL_PKT_SIZE);
539 	priv->pending_setup.divisor = buf->divisor;
540 	priv->pending_setup.frame_fmt = buf->frame_fmt;
541 	priv->pending_setup.control = buf->control;
542 	spin_unlock_irqrestore(&priv->lock, flags);
543 	kfree(buf);
544 
545 	dev_dbg(&port->dev, "%s(): submitting interrupt urb\n", __func__);
546 	result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
547 	if (result != 0) {
548 		dev_err(&port->dev, "%s(): usb_submit_urb() failed with error %d\n",
549 			__func__, result);
550 		oti6858_close(port);
551 		return result;
552 	}
553 
554 	/* setup termios */
555 	if (tty)
556 		oti6858_set_termios(tty, port, NULL);
557 
558 	return 0;
559 }
560 
561 static void oti6858_close(struct usb_serial_port *port)
562 {
563 	struct oti6858_private *priv = usb_get_serial_port_data(port);
564 	unsigned long flags;
565 
566 	spin_lock_irqsave(&port->lock, flags);
567 	/* clear out any remaining data in the buffer */
568 	kfifo_reset_out(&port->write_fifo);
569 	spin_unlock_irqrestore(&port->lock, flags);
570 
571 	dev_dbg(&port->dev, "%s(): after buf_clear()\n", __func__);
572 
573 	/* cancel scheduled setup */
574 	cancel_delayed_work_sync(&priv->delayed_setup_work);
575 	cancel_delayed_work_sync(&priv->delayed_write_work);
576 
577 	/* shutdown our urbs */
578 	dev_dbg(&port->dev, "%s(): shutting down urbs\n", __func__);
579 	usb_kill_urb(port->write_urb);
580 	usb_kill_urb(port->read_urb);
581 	usb_kill_urb(port->interrupt_in_urb);
582 }
583 
584 static int oti6858_tiocmset(struct tty_struct *tty,
585 				unsigned int set, unsigned int clear)
586 {
587 	struct usb_serial_port *port = tty->driver_data;
588 	struct oti6858_private *priv = usb_get_serial_port_data(port);
589 	unsigned long flags;
590 	u8 control;
591 
592 	dev_dbg(&port->dev, "%s(set = 0x%08x, clear = 0x%08x)\n",
593 		__func__, set, clear);
594 
595 	/* FIXME: check if this is correct (active high/low) */
596 	spin_lock_irqsave(&priv->lock, flags);
597 	control = priv->pending_setup.control;
598 	if ((set & TIOCM_RTS) != 0)
599 		control |= CONTROL_RTS_HIGH;
600 	if ((set & TIOCM_DTR) != 0)
601 		control |= CONTROL_DTR_HIGH;
602 	if ((clear & TIOCM_RTS) != 0)
603 		control &= ~CONTROL_RTS_HIGH;
604 	if ((clear & TIOCM_DTR) != 0)
605 		control &= ~CONTROL_DTR_HIGH;
606 
607 	if (control != priv->pending_setup.control)
608 		priv->pending_setup.control = control;
609 
610 	spin_unlock_irqrestore(&priv->lock, flags);
611 	return 0;
612 }
613 
614 static int oti6858_tiocmget(struct tty_struct *tty)
615 {
616 	struct usb_serial_port *port = tty->driver_data;
617 	struct oti6858_private *priv = usb_get_serial_port_data(port);
618 	unsigned long flags;
619 	unsigned pin_state;
620 	unsigned result = 0;
621 
622 	spin_lock_irqsave(&priv->lock, flags);
623 	pin_state = priv->status.pin_state & PIN_MASK;
624 	spin_unlock_irqrestore(&priv->lock, flags);
625 
626 	/* FIXME: check if this is correct (active high/low) */
627 	if ((pin_state & PIN_RTS) != 0)
628 		result |= TIOCM_RTS;
629 	if ((pin_state & PIN_CTS) != 0)
630 		result |= TIOCM_CTS;
631 	if ((pin_state & PIN_DSR) != 0)
632 		result |= TIOCM_DSR;
633 	if ((pin_state & PIN_DTR) != 0)
634 		result |= TIOCM_DTR;
635 	if ((pin_state & PIN_RI) != 0)
636 		result |= TIOCM_RI;
637 	if ((pin_state & PIN_DCD) != 0)
638 		result |= TIOCM_CD;
639 
640 	dev_dbg(&port->dev, "%s() = 0x%08x\n", __func__, result);
641 
642 	return result;
643 }
644 
645 static void oti6858_read_int_callback(struct urb *urb)
646 {
647 	struct usb_serial_port *port =  urb->context;
648 	struct oti6858_private *priv = usb_get_serial_port_data(port);
649 	int transient = 0, can_recv = 0, resubmit = 1;
650 	int status = urb->status;
651 
652 	switch (status) {
653 	case 0:
654 		/* success */
655 		break;
656 	case -ECONNRESET:
657 	case -ENOENT:
658 	case -ESHUTDOWN:
659 		/* this urb is terminated, clean up */
660 		dev_dbg(&urb->dev->dev, "%s(): urb shutting down with status: %d\n",
661 			__func__, status);
662 		return;
663 	default:
664 		dev_dbg(&urb->dev->dev, "%s(): nonzero urb status received: %d\n",
665 			__func__, status);
666 		break;
667 	}
668 
669 	if (status == 0 && urb->actual_length == OTI6858_CTRL_PKT_SIZE) {
670 		struct oti6858_control_pkt *xs = urb->transfer_buffer;
671 		unsigned long flags;
672 
673 		spin_lock_irqsave(&priv->lock, flags);
674 
675 		if (!priv->transient) {
676 			if (!OTI6858_CTRL_EQUALS_PENDING(xs, priv)) {
677 				if (xs->rx_bytes_avail == 0) {
678 					priv->transient = 4;
679 					priv->setup_done = 0;
680 					resubmit = 0;
681 					dev_dbg(&port->dev, "%s(): scheduling setup_line()\n", __func__);
682 					schedule_delayed_work(&priv->delayed_setup_work, 0);
683 				}
684 			}
685 		} else {
686 			if (OTI6858_CTRL_EQUALS_PENDING(xs, priv)) {
687 				priv->transient = 0;
688 			} else if (!priv->setup_done) {
689 				resubmit = 0;
690 			} else if (--priv->transient == 0) {
691 				if (xs->rx_bytes_avail == 0) {
692 					priv->transient = 4;
693 					priv->setup_done = 0;
694 					resubmit = 0;
695 					dev_dbg(&port->dev, "%s(): scheduling setup_line()\n", __func__);
696 					schedule_delayed_work(&priv->delayed_setup_work, 0);
697 				}
698 			}
699 		}
700 
701 		if (!priv->transient) {
702 			u8 delta = xs->pin_state ^ priv->status.pin_state;
703 
704 			if (delta & PIN_MSR_MASK) {
705 				if (delta & PIN_CTS)
706 					port->icount.cts++;
707 				if (delta & PIN_DSR)
708 					port->icount.dsr++;
709 				if (delta & PIN_RI)
710 					port->icount.rng++;
711 				if (delta & PIN_DCD)
712 					port->icount.dcd++;
713 
714 				wake_up_interruptible(&port->port.delta_msr_wait);
715 			}
716 
717 			memcpy(&priv->status, xs, OTI6858_CTRL_PKT_SIZE);
718 		}
719 
720 		if (!priv->transient && xs->rx_bytes_avail != 0) {
721 			can_recv = xs->rx_bytes_avail;
722 			priv->flags.read_urb_in_use = 1;
723 		}
724 
725 		transient = priv->transient;
726 		spin_unlock_irqrestore(&priv->lock, flags);
727 	}
728 
729 	if (can_recv) {
730 		int result;
731 
732 		result = usb_submit_urb(port->read_urb, GFP_ATOMIC);
733 		if (result != 0) {
734 			priv->flags.read_urb_in_use = 0;
735 			dev_err(&port->dev, "%s(): usb_submit_urb() failed,"
736 					" error %d\n", __func__, result);
737 		} else {
738 			resubmit = 0;
739 		}
740 	} else if (!transient) {
741 		unsigned long flags;
742 		int count;
743 
744 		spin_lock_irqsave(&port->lock, flags);
745 		count = kfifo_len(&port->write_fifo);
746 		spin_unlock_irqrestore(&port->lock, flags);
747 
748 		spin_lock_irqsave(&priv->lock, flags);
749 		if (priv->flags.write_urb_in_use == 0 && count != 0) {
750 			schedule_delayed_work(&priv->delayed_write_work, 0);
751 			resubmit = 0;
752 		}
753 		spin_unlock_irqrestore(&priv->lock, flags);
754 	}
755 
756 	if (resubmit) {
757 		int result;
758 
759 /*		dev_dbg(&urb->dev->dev, "%s(): submitting interrupt urb\n", __func__); */
760 		result = usb_submit_urb(urb, GFP_ATOMIC);
761 		if (result != 0) {
762 			dev_err(&urb->dev->dev,
763 					"%s(): usb_submit_urb() failed with"
764 					" error %d\n", __func__, result);
765 		}
766 	}
767 }
768 
769 static void oti6858_read_bulk_callback(struct urb *urb)
770 {
771 	struct usb_serial_port *port =  urb->context;
772 	struct oti6858_private *priv = usb_get_serial_port_data(port);
773 	unsigned char *data = urb->transfer_buffer;
774 	unsigned long flags;
775 	int status = urb->status;
776 	int result;
777 
778 	spin_lock_irqsave(&priv->lock, flags);
779 	priv->flags.read_urb_in_use = 0;
780 	spin_unlock_irqrestore(&priv->lock, flags);
781 
782 	if (status != 0) {
783 		dev_dbg(&urb->dev->dev, "%s(): unable to handle the error, exiting\n", __func__);
784 		return;
785 	}
786 
787 	if (urb->actual_length > 0) {
788 		tty_insert_flip_string(&port->port, data, urb->actual_length);
789 		tty_flip_buffer_push(&port->port);
790 	}
791 
792 	/* schedule the interrupt urb */
793 	result = usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC);
794 	if (result != 0 && result != -EPERM) {
795 		dev_err(&port->dev, "%s(): usb_submit_urb() failed,"
796 				" error %d\n", __func__, result);
797 	}
798 }
799 
800 static void oti6858_write_bulk_callback(struct urb *urb)
801 {
802 	struct usb_serial_port *port =  urb->context;
803 	struct oti6858_private *priv = usb_get_serial_port_data(port);
804 	int status = urb->status;
805 	int result;
806 
807 	switch (status) {
808 	case 0:
809 		/* success */
810 		break;
811 	case -ECONNRESET:
812 	case -ENOENT:
813 	case -ESHUTDOWN:
814 		/* this urb is terminated, clean up */
815 		dev_dbg(&urb->dev->dev, "%s(): urb shutting down with status: %d\n", __func__, status);
816 		priv->flags.write_urb_in_use = 0;
817 		return;
818 	default:
819 		/* error in the urb, so we have to resubmit it */
820 		dev_dbg(&urb->dev->dev, "%s(): nonzero write bulk status received: %d\n", __func__, status);
821 		dev_dbg(&urb->dev->dev, "%s(): overflow in write\n", __func__);
822 
823 		port->write_urb->transfer_buffer_length = 1;
824 		result = usb_submit_urb(port->write_urb, GFP_ATOMIC);
825 		if (result) {
826 			dev_err_console(port, "%s(): usb_submit_urb() failed,"
827 					" error %d\n", __func__, result);
828 		} else {
829 			return;
830 		}
831 	}
832 
833 	priv->flags.write_urb_in_use = 0;
834 
835 	/* schedule the interrupt urb if we are still open */
836 	dev_dbg(&port->dev, "%s(): submitting interrupt urb\n", __func__);
837 	result = usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC);
838 	if (result != 0) {
839 		dev_err(&port->dev, "%s(): failed submitting int urb,"
840 					" error %d\n", __func__, result);
841 	}
842 }
843 
844 module_usb_serial_driver(serial_drivers, id_table);
845 
846 MODULE_DESCRIPTION(OTI6858_DESCRIPTION);
847 MODULE_AUTHOR(OTI6858_AUTHOR);
848 MODULE_LICENSE("GPL");
849