xref: /linux/drivers/usb/serial/oti6858.c (revision 87c9c16317882dd6dbbc07e349bc3223e14f3244)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Ours Technology Inc. OTi-6858 USB to serial adapter driver.
4  *
5  * Copyleft  (C) 2007 Kees Lemmens (adapted for kernel 2.6.20)
6  * Copyright (C) 2006 Tomasz Michal Lukaszewski (FIXME: add e-mail)
7  * Copyright (C) 2001-2004 Greg Kroah-Hartman (greg@kroah.com)
8  * Copyright (C) 2003 IBM Corp.
9  *
10  * Many thanks to the authors of pl2303 driver: all functions in this file
11  * are heavily based on pl2303 code, buffering code is a 1-to-1 copy.
12  *
13  * Warning! You use this driver on your own risk! The only official
14  * description of this device I have is datasheet from manufacturer,
15  * and it doesn't contain almost any information needed to write a driver.
16  * Almost all knowlegde used while writing this driver was gathered by:
17  *  - analyzing traffic between device and the M$ Windows 2000 driver,
18  *  - trying different bit combinations and checking pin states
19  *    with a voltmeter,
20  *  - receiving malformed frames and producing buffer overflows
21  *    to learn how errors are reported,
22  * So, THIS CODE CAN DESTROY OTi-6858 AND ANY OTHER DEVICES, THAT ARE
23  * CONNECTED TO IT!
24  *
25  * See Documentation/usb/usb-serial.rst for more information on using this
26  * driver
27  *
28  * TODO:
29  *  - implement correct flushing for ioctls and oti6858_close()
30  *  - check how errors (rx overflow, parity error, framing error) are reported
31  *  - implement oti6858_break_ctl()
32  *  - implement more ioctls
33  *  - test/implement flow control
34  *  - allow setting custom baud rates
35  */
36 
37 #include <linux/kernel.h>
38 #include <linux/errno.h>
39 #include <linux/slab.h>
40 #include <linux/tty.h>
41 #include <linux/tty_driver.h>
42 #include <linux/tty_flip.h>
43 #include <linux/serial.h>
44 #include <linux/module.h>
45 #include <linux/moduleparam.h>
46 #include <linux/spinlock.h>
47 #include <linux/usb.h>
48 #include <linux/usb/serial.h>
49 #include <linux/uaccess.h>
50 #include <linux/kfifo.h>
51 #include "oti6858.h"
52 
53 #define OTI6858_DESCRIPTION \
54 	"Ours Technology Inc. OTi-6858 USB to serial adapter driver"
55 #define OTI6858_AUTHOR "Tomasz Michal Lukaszewski <FIXME@FIXME>"
56 
57 static const struct usb_device_id id_table[] = {
58 	{ USB_DEVICE(OTI6858_VENDOR_ID, OTI6858_PRODUCT_ID) },
59 	{ }
60 };
61 
62 MODULE_DEVICE_TABLE(usb, id_table);
63 
64 /* requests */
65 #define	OTI6858_REQ_GET_STATUS		(USB_DIR_IN | USB_TYPE_VENDOR | 0x00)
66 #define	OTI6858_REQ_T_GET_STATUS	0x01
67 
68 #define	OTI6858_REQ_SET_LINE		(USB_DIR_OUT | USB_TYPE_VENDOR | 0x00)
69 #define	OTI6858_REQ_T_SET_LINE		0x00
70 
71 #define	OTI6858_REQ_CHECK_TXBUFF	(USB_DIR_IN | USB_TYPE_VENDOR | 0x01)
72 #define	OTI6858_REQ_T_CHECK_TXBUFF	0x00
73 
74 /* format of the control packet */
75 struct oti6858_control_pkt {
76 	__le16	divisor;	/* baud rate = 96000000 / (16 * divisor), LE */
77 #define OTI6858_MAX_BAUD_RATE	3000000
78 	u8	frame_fmt;
79 #define FMT_STOP_BITS_MASK	0xc0
80 #define FMT_STOP_BITS_1		0x00
81 #define FMT_STOP_BITS_2		0x40	/* 1.5 stop bits if FMT_DATA_BITS_5 */
82 #define FMT_PARITY_MASK		0x38
83 #define FMT_PARITY_NONE		0x00
84 #define FMT_PARITY_ODD		0x08
85 #define FMT_PARITY_EVEN		0x18
86 #define FMT_PARITY_MARK		0x28
87 #define FMT_PARITY_SPACE	0x38
88 #define FMT_DATA_BITS_MASK	0x03
89 #define FMT_DATA_BITS_5		0x00
90 #define FMT_DATA_BITS_6		0x01
91 #define FMT_DATA_BITS_7		0x02
92 #define FMT_DATA_BITS_8		0x03
93 	u8	something;	/* always equals 0x43 */
94 	u8	control;	/* settings of flow control lines */
95 #define CONTROL_MASK		0x0c
96 #define CONTROL_DTR_HIGH	0x08
97 #define CONTROL_RTS_HIGH	0x04
98 	u8	tx_status;
99 #define	TX_BUFFER_EMPTIED	0x09
100 	u8	pin_state;
101 #define PIN_MASK		0x3f
102 #define PIN_MSR_MASK		0x1b
103 #define PIN_RTS			0x20	/* output pin */
104 #define PIN_CTS			0x10	/* input pin, active low */
105 #define PIN_DSR			0x08	/* input pin, active low */
106 #define PIN_DTR			0x04	/* output pin */
107 #define PIN_RI			0x02	/* input pin, active low */
108 #define PIN_DCD			0x01	/* input pin, active low */
109 	u8	rx_bytes_avail;		/* number of bytes in rx buffer */;
110 };
111 
112 #define OTI6858_CTRL_PKT_SIZE	sizeof(struct oti6858_control_pkt)
113 #define OTI6858_CTRL_EQUALS_PENDING(a, priv) \
114 	(((a)->divisor == (priv)->pending_setup.divisor) \
115 	  && ((a)->control == (priv)->pending_setup.control) \
116 	  && ((a)->frame_fmt == (priv)->pending_setup.frame_fmt))
117 
118 /* function prototypes */
119 static int oti6858_open(struct tty_struct *tty, struct usb_serial_port *port);
120 static void oti6858_close(struct usb_serial_port *port);
121 static void oti6858_set_termios(struct tty_struct *tty,
122 			struct usb_serial_port *port, struct ktermios *old);
123 static void oti6858_init_termios(struct tty_struct *tty);
124 static void oti6858_read_int_callback(struct urb *urb);
125 static void oti6858_read_bulk_callback(struct urb *urb);
126 static void oti6858_write_bulk_callback(struct urb *urb);
127 static int oti6858_write(struct tty_struct *tty, struct usb_serial_port *port,
128 			const unsigned char *buf, int count);
129 static int oti6858_write_room(struct tty_struct *tty);
130 static int oti6858_chars_in_buffer(struct tty_struct *tty);
131 static int oti6858_tiocmget(struct tty_struct *tty);
132 static int oti6858_tiocmset(struct tty_struct *tty,
133 				unsigned int set, unsigned int clear);
134 static int oti6858_port_probe(struct usb_serial_port *port);
135 static void oti6858_port_remove(struct usb_serial_port *port);
136 
137 /* device info */
138 static struct usb_serial_driver oti6858_device = {
139 	.driver = {
140 		.owner =	THIS_MODULE,
141 		.name =		"oti6858",
142 	},
143 	.id_table =		id_table,
144 	.num_ports =		1,
145 	.num_bulk_in =		1,
146 	.num_bulk_out =		1,
147 	.num_interrupt_in =	1,
148 	.open =			oti6858_open,
149 	.close =		oti6858_close,
150 	.write =		oti6858_write,
151 	.set_termios =		oti6858_set_termios,
152 	.init_termios = 	oti6858_init_termios,
153 	.tiocmget =		oti6858_tiocmget,
154 	.tiocmset =		oti6858_tiocmset,
155 	.tiocmiwait =		usb_serial_generic_tiocmiwait,
156 	.read_bulk_callback =	oti6858_read_bulk_callback,
157 	.read_int_callback =	oti6858_read_int_callback,
158 	.write_bulk_callback =	oti6858_write_bulk_callback,
159 	.write_room =		oti6858_write_room,
160 	.chars_in_buffer =	oti6858_chars_in_buffer,
161 	.port_probe =		oti6858_port_probe,
162 	.port_remove =		oti6858_port_remove,
163 };
164 
165 static struct usb_serial_driver * const serial_drivers[] = {
166 	&oti6858_device, NULL
167 };
168 
169 struct oti6858_private {
170 	spinlock_t lock;
171 
172 	struct oti6858_control_pkt status;
173 
174 	struct {
175 		u8 read_urb_in_use;
176 		u8 write_urb_in_use;
177 	} flags;
178 	struct delayed_work delayed_write_work;
179 
180 	struct {
181 		__le16 divisor;
182 		u8 frame_fmt;
183 		u8 control;
184 	} pending_setup;
185 	u8 transient;
186 	u8 setup_done;
187 	struct delayed_work delayed_setup_work;
188 
189 	struct usb_serial_port *port;   /* USB port with which associated */
190 };
191 
192 static void setup_line(struct work_struct *work)
193 {
194 	struct oti6858_private *priv = container_of(work,
195 			struct oti6858_private, delayed_setup_work.work);
196 	struct usb_serial_port *port = priv->port;
197 	struct oti6858_control_pkt *new_setup;
198 	unsigned long flags;
199 	int result;
200 
201 	new_setup = kmalloc(OTI6858_CTRL_PKT_SIZE, GFP_KERNEL);
202 	if (!new_setup) {
203 		/* we will try again */
204 		schedule_delayed_work(&priv->delayed_setup_work,
205 						msecs_to_jiffies(2));
206 		return;
207 	}
208 
209 	result = usb_control_msg(port->serial->dev,
210 				usb_rcvctrlpipe(port->serial->dev, 0),
211 				OTI6858_REQ_T_GET_STATUS,
212 				OTI6858_REQ_GET_STATUS,
213 				0, 0,
214 				new_setup, OTI6858_CTRL_PKT_SIZE,
215 				100);
216 
217 	if (result != OTI6858_CTRL_PKT_SIZE) {
218 		dev_err(&port->dev, "%s(): error reading status\n", __func__);
219 		kfree(new_setup);
220 		/* we will try again */
221 		schedule_delayed_work(&priv->delayed_setup_work,
222 							msecs_to_jiffies(2));
223 		return;
224 	}
225 
226 	spin_lock_irqsave(&priv->lock, flags);
227 	if (!OTI6858_CTRL_EQUALS_PENDING(new_setup, priv)) {
228 		new_setup->divisor = priv->pending_setup.divisor;
229 		new_setup->control = priv->pending_setup.control;
230 		new_setup->frame_fmt = priv->pending_setup.frame_fmt;
231 
232 		spin_unlock_irqrestore(&priv->lock, flags);
233 		result = usb_control_msg(port->serial->dev,
234 					usb_sndctrlpipe(port->serial->dev, 0),
235 					OTI6858_REQ_T_SET_LINE,
236 					OTI6858_REQ_SET_LINE,
237 					0, 0,
238 					new_setup, OTI6858_CTRL_PKT_SIZE,
239 					100);
240 	} else {
241 		spin_unlock_irqrestore(&priv->lock, flags);
242 		result = 0;
243 	}
244 	kfree(new_setup);
245 
246 	spin_lock_irqsave(&priv->lock, flags);
247 	if (result != OTI6858_CTRL_PKT_SIZE)
248 		priv->transient = 0;
249 	priv->setup_done = 1;
250 	spin_unlock_irqrestore(&priv->lock, flags);
251 
252 	dev_dbg(&port->dev, "%s(): submitting interrupt urb\n", __func__);
253 	result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
254 	if (result != 0) {
255 		dev_err(&port->dev, "%s(): usb_submit_urb() failed with error %d\n",
256 			__func__, result);
257 	}
258 }
259 
260 static void send_data(struct work_struct *work)
261 {
262 	struct oti6858_private *priv = container_of(work,
263 			struct oti6858_private, delayed_write_work.work);
264 	struct usb_serial_port *port = priv->port;
265 	int count = 0, result;
266 	unsigned long flags;
267 	u8 *allow;
268 
269 	spin_lock_irqsave(&priv->lock, flags);
270 	if (priv->flags.write_urb_in_use) {
271 		spin_unlock_irqrestore(&priv->lock, flags);
272 		schedule_delayed_work(&priv->delayed_write_work,
273 						msecs_to_jiffies(2));
274 		return;
275 	}
276 	priv->flags.write_urb_in_use = 1;
277 	spin_unlock_irqrestore(&priv->lock, flags);
278 
279 	spin_lock_irqsave(&port->lock, flags);
280 	count = kfifo_len(&port->write_fifo);
281 	spin_unlock_irqrestore(&port->lock, flags);
282 
283 	if (count > port->bulk_out_size)
284 		count = port->bulk_out_size;
285 
286 	if (count != 0) {
287 		allow = kmalloc(1, GFP_KERNEL);
288 		if (!allow)
289 			return;
290 
291 		result = usb_control_msg(port->serial->dev,
292 				usb_rcvctrlpipe(port->serial->dev, 0),
293 				OTI6858_REQ_T_CHECK_TXBUFF,
294 				OTI6858_REQ_CHECK_TXBUFF,
295 				count, 0, allow, 1, 100);
296 		if (result != 1 || *allow != 0)
297 			count = 0;
298 		kfree(allow);
299 	}
300 
301 	if (count == 0) {
302 		priv->flags.write_urb_in_use = 0;
303 
304 		dev_dbg(&port->dev, "%s(): submitting interrupt urb\n", __func__);
305 		result = usb_submit_urb(port->interrupt_in_urb, GFP_NOIO);
306 		if (result != 0) {
307 			dev_err(&port->dev, "%s(): usb_submit_urb() failed with error %d\n",
308 				__func__, result);
309 		}
310 		return;
311 	}
312 
313 	count = kfifo_out_locked(&port->write_fifo,
314 					port->write_urb->transfer_buffer,
315 					count, &port->lock);
316 	port->write_urb->transfer_buffer_length = count;
317 	result = usb_submit_urb(port->write_urb, GFP_NOIO);
318 	if (result != 0) {
319 		dev_err_console(port, "%s(): usb_submit_urb() failed with error %d\n",
320 				__func__, result);
321 		priv->flags.write_urb_in_use = 0;
322 	}
323 
324 	usb_serial_port_softint(port);
325 }
326 
327 static int oti6858_port_probe(struct usb_serial_port *port)
328 {
329 	struct oti6858_private *priv;
330 
331 	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
332 	if (!priv)
333 		return -ENOMEM;
334 
335 	spin_lock_init(&priv->lock);
336 	priv->port = port;
337 	INIT_DELAYED_WORK(&priv->delayed_setup_work, setup_line);
338 	INIT_DELAYED_WORK(&priv->delayed_write_work, send_data);
339 
340 	usb_set_serial_port_data(port, priv);
341 
342 	port->port.drain_delay = 256;	/* FIXME: check the FIFO length */
343 
344 	return 0;
345 }
346 
347 static void oti6858_port_remove(struct usb_serial_port *port)
348 {
349 	struct oti6858_private *priv;
350 
351 	priv = usb_get_serial_port_data(port);
352 	kfree(priv);
353 }
354 
355 static int oti6858_write(struct tty_struct *tty, struct usb_serial_port *port,
356 			const unsigned char *buf, int count)
357 {
358 	if (!count)
359 		return count;
360 
361 	count = kfifo_in_locked(&port->write_fifo, buf, count, &port->lock);
362 
363 	return count;
364 }
365 
366 static int oti6858_write_room(struct tty_struct *tty)
367 {
368 	struct usb_serial_port *port = tty->driver_data;
369 	int room = 0;
370 	unsigned long flags;
371 
372 	spin_lock_irqsave(&port->lock, flags);
373 	room = kfifo_avail(&port->write_fifo);
374 	spin_unlock_irqrestore(&port->lock, flags);
375 
376 	return room;
377 }
378 
379 static int oti6858_chars_in_buffer(struct tty_struct *tty)
380 {
381 	struct usb_serial_port *port = tty->driver_data;
382 	int chars = 0;
383 	unsigned long flags;
384 
385 	spin_lock_irqsave(&port->lock, flags);
386 	chars = kfifo_len(&port->write_fifo);
387 	spin_unlock_irqrestore(&port->lock, flags);
388 
389 	return chars;
390 }
391 
392 static void oti6858_init_termios(struct tty_struct *tty)
393 {
394 	tty_encode_baud_rate(tty, 38400, 38400);
395 }
396 
397 static void oti6858_set_termios(struct tty_struct *tty,
398 		struct usb_serial_port *port, struct ktermios *old_termios)
399 {
400 	struct oti6858_private *priv = usb_get_serial_port_data(port);
401 	unsigned long flags;
402 	unsigned int cflag;
403 	u8 frame_fmt, control;
404 	__le16 divisor;
405 	int br;
406 
407 	cflag = tty->termios.c_cflag;
408 
409 	spin_lock_irqsave(&priv->lock, flags);
410 	divisor = priv->pending_setup.divisor;
411 	frame_fmt = priv->pending_setup.frame_fmt;
412 	control = priv->pending_setup.control;
413 	spin_unlock_irqrestore(&priv->lock, flags);
414 
415 	frame_fmt &= ~FMT_DATA_BITS_MASK;
416 	switch (cflag & CSIZE) {
417 	case CS5:
418 		frame_fmt |= FMT_DATA_BITS_5;
419 		break;
420 	case CS6:
421 		frame_fmt |= FMT_DATA_BITS_6;
422 		break;
423 	case CS7:
424 		frame_fmt |= FMT_DATA_BITS_7;
425 		break;
426 	default:
427 	case CS8:
428 		frame_fmt |= FMT_DATA_BITS_8;
429 		break;
430 	}
431 
432 	/* manufacturer claims that this device can work with baud rates
433 	 * up to 3 Mbps; I've tested it only on 115200 bps, so I can't
434 	 * guarantee that any other baud rate will work (especially
435 	 * the higher ones)
436 	 */
437 	br = tty_get_baud_rate(tty);
438 	if (br == 0) {
439 		divisor = 0;
440 	} else {
441 		int real_br;
442 		int new_divisor;
443 		br = min(br, OTI6858_MAX_BAUD_RATE);
444 
445 		new_divisor = (96000000 + 8 * br) / (16 * br);
446 		real_br = 96000000 / (16 * new_divisor);
447 		divisor = cpu_to_le16(new_divisor);
448 		tty_encode_baud_rate(tty, real_br, real_br);
449 	}
450 
451 	frame_fmt &= ~FMT_STOP_BITS_MASK;
452 	if ((cflag & CSTOPB) != 0)
453 		frame_fmt |= FMT_STOP_BITS_2;
454 	else
455 		frame_fmt |= FMT_STOP_BITS_1;
456 
457 	frame_fmt &= ~FMT_PARITY_MASK;
458 	if ((cflag & PARENB) != 0) {
459 		if ((cflag & PARODD) != 0)
460 			frame_fmt |= FMT_PARITY_ODD;
461 		else
462 			frame_fmt |= FMT_PARITY_EVEN;
463 	} else {
464 		frame_fmt |= FMT_PARITY_NONE;
465 	}
466 
467 	control &= ~CONTROL_MASK;
468 	if ((cflag & CRTSCTS) != 0)
469 		control |= (CONTROL_DTR_HIGH | CONTROL_RTS_HIGH);
470 
471 	/* change control lines if we are switching to or from B0 */
472 	/* FIXME:
473 	spin_lock_irqsave(&priv->lock, flags);
474 	control = priv->line_control;
475 	if ((cflag & CBAUD) == B0)
476 		priv->line_control &= ~(CONTROL_DTR | CONTROL_RTS);
477 	else
478 		priv->line_control |= (CONTROL_DTR | CONTROL_RTS);
479 	if (control != priv->line_control) {
480 		control = priv->line_control;
481 		spin_unlock_irqrestore(&priv->lock, flags);
482 		set_control_lines(serial->dev, control);
483 	} else {
484 		spin_unlock_irqrestore(&priv->lock, flags);
485 	}
486 	*/
487 
488 	spin_lock_irqsave(&priv->lock, flags);
489 	if (divisor != priv->pending_setup.divisor
490 			|| control != priv->pending_setup.control
491 			|| frame_fmt != priv->pending_setup.frame_fmt) {
492 		priv->pending_setup.divisor = divisor;
493 		priv->pending_setup.control = control;
494 		priv->pending_setup.frame_fmt = frame_fmt;
495 	}
496 	spin_unlock_irqrestore(&priv->lock, flags);
497 }
498 
499 static int oti6858_open(struct tty_struct *tty, struct usb_serial_port *port)
500 {
501 	struct oti6858_private *priv = usb_get_serial_port_data(port);
502 	struct usb_serial *serial = port->serial;
503 	struct oti6858_control_pkt *buf;
504 	unsigned long flags;
505 	int result;
506 
507 	usb_clear_halt(serial->dev, port->write_urb->pipe);
508 	usb_clear_halt(serial->dev, port->read_urb->pipe);
509 
510 	buf = kmalloc(OTI6858_CTRL_PKT_SIZE, GFP_KERNEL);
511 	if (!buf)
512 		return -ENOMEM;
513 
514 	result = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
515 				OTI6858_REQ_T_GET_STATUS,
516 				OTI6858_REQ_GET_STATUS,
517 				0, 0,
518 				buf, OTI6858_CTRL_PKT_SIZE,
519 				100);
520 	if (result != OTI6858_CTRL_PKT_SIZE) {
521 		/* assume default (after power-on reset) values */
522 		buf->divisor = cpu_to_le16(0x009c);	/* 38400 bps */
523 		buf->frame_fmt = 0x03;	/* 8N1 */
524 		buf->something = 0x43;
525 		buf->control = 0x4c;	/* DTR, RTS */
526 		buf->tx_status = 0x00;
527 		buf->pin_state = 0x5b;	/* RTS, CTS, DSR, DTR, RI, DCD */
528 		buf->rx_bytes_avail = 0x00;
529 	}
530 
531 	spin_lock_irqsave(&priv->lock, flags);
532 	memcpy(&priv->status, buf, OTI6858_CTRL_PKT_SIZE);
533 	priv->pending_setup.divisor = buf->divisor;
534 	priv->pending_setup.frame_fmt = buf->frame_fmt;
535 	priv->pending_setup.control = buf->control;
536 	spin_unlock_irqrestore(&priv->lock, flags);
537 	kfree(buf);
538 
539 	dev_dbg(&port->dev, "%s(): submitting interrupt urb\n", __func__);
540 	result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
541 	if (result != 0) {
542 		dev_err(&port->dev, "%s(): usb_submit_urb() failed with error %d\n",
543 			__func__, result);
544 		oti6858_close(port);
545 		return result;
546 	}
547 
548 	/* setup termios */
549 	if (tty)
550 		oti6858_set_termios(tty, port, NULL);
551 
552 	return 0;
553 }
554 
555 static void oti6858_close(struct usb_serial_port *port)
556 {
557 	struct oti6858_private *priv = usb_get_serial_port_data(port);
558 	unsigned long flags;
559 
560 	spin_lock_irqsave(&port->lock, flags);
561 	/* clear out any remaining data in the buffer */
562 	kfifo_reset_out(&port->write_fifo);
563 	spin_unlock_irqrestore(&port->lock, flags);
564 
565 	dev_dbg(&port->dev, "%s(): after buf_clear()\n", __func__);
566 
567 	/* cancel scheduled setup */
568 	cancel_delayed_work_sync(&priv->delayed_setup_work);
569 	cancel_delayed_work_sync(&priv->delayed_write_work);
570 
571 	/* shutdown our urbs */
572 	dev_dbg(&port->dev, "%s(): shutting down urbs\n", __func__);
573 	usb_kill_urb(port->write_urb);
574 	usb_kill_urb(port->read_urb);
575 	usb_kill_urb(port->interrupt_in_urb);
576 }
577 
578 static int oti6858_tiocmset(struct tty_struct *tty,
579 				unsigned int set, unsigned int clear)
580 {
581 	struct usb_serial_port *port = tty->driver_data;
582 	struct oti6858_private *priv = usb_get_serial_port_data(port);
583 	unsigned long flags;
584 	u8 control;
585 
586 	dev_dbg(&port->dev, "%s(set = 0x%08x, clear = 0x%08x)\n",
587 		__func__, set, clear);
588 
589 	/* FIXME: check if this is correct (active high/low) */
590 	spin_lock_irqsave(&priv->lock, flags);
591 	control = priv->pending_setup.control;
592 	if ((set & TIOCM_RTS) != 0)
593 		control |= CONTROL_RTS_HIGH;
594 	if ((set & TIOCM_DTR) != 0)
595 		control |= CONTROL_DTR_HIGH;
596 	if ((clear & TIOCM_RTS) != 0)
597 		control &= ~CONTROL_RTS_HIGH;
598 	if ((clear & TIOCM_DTR) != 0)
599 		control &= ~CONTROL_DTR_HIGH;
600 
601 	if (control != priv->pending_setup.control)
602 		priv->pending_setup.control = control;
603 
604 	spin_unlock_irqrestore(&priv->lock, flags);
605 	return 0;
606 }
607 
608 static int oti6858_tiocmget(struct tty_struct *tty)
609 {
610 	struct usb_serial_port *port = tty->driver_data;
611 	struct oti6858_private *priv = usb_get_serial_port_data(port);
612 	unsigned long flags;
613 	unsigned pin_state;
614 	unsigned result = 0;
615 
616 	spin_lock_irqsave(&priv->lock, flags);
617 	pin_state = priv->status.pin_state & PIN_MASK;
618 	spin_unlock_irqrestore(&priv->lock, flags);
619 
620 	/* FIXME: check if this is correct (active high/low) */
621 	if ((pin_state & PIN_RTS) != 0)
622 		result |= TIOCM_RTS;
623 	if ((pin_state & PIN_CTS) != 0)
624 		result |= TIOCM_CTS;
625 	if ((pin_state & PIN_DSR) != 0)
626 		result |= TIOCM_DSR;
627 	if ((pin_state & PIN_DTR) != 0)
628 		result |= TIOCM_DTR;
629 	if ((pin_state & PIN_RI) != 0)
630 		result |= TIOCM_RI;
631 	if ((pin_state & PIN_DCD) != 0)
632 		result |= TIOCM_CD;
633 
634 	dev_dbg(&port->dev, "%s() = 0x%08x\n", __func__, result);
635 
636 	return result;
637 }
638 
639 static void oti6858_read_int_callback(struct urb *urb)
640 {
641 	struct usb_serial_port *port =  urb->context;
642 	struct oti6858_private *priv = usb_get_serial_port_data(port);
643 	int transient = 0, can_recv = 0, resubmit = 1;
644 	int status = urb->status;
645 
646 	switch (status) {
647 	case 0:
648 		/* success */
649 		break;
650 	case -ECONNRESET:
651 	case -ENOENT:
652 	case -ESHUTDOWN:
653 		/* this urb is terminated, clean up */
654 		dev_dbg(&urb->dev->dev, "%s(): urb shutting down with status: %d\n",
655 			__func__, status);
656 		return;
657 	default:
658 		dev_dbg(&urb->dev->dev, "%s(): nonzero urb status received: %d\n",
659 			__func__, status);
660 		break;
661 	}
662 
663 	if (status == 0 && urb->actual_length == OTI6858_CTRL_PKT_SIZE) {
664 		struct oti6858_control_pkt *xs = urb->transfer_buffer;
665 		unsigned long flags;
666 
667 		spin_lock_irqsave(&priv->lock, flags);
668 
669 		if (!priv->transient) {
670 			if (!OTI6858_CTRL_EQUALS_PENDING(xs, priv)) {
671 				if (xs->rx_bytes_avail == 0) {
672 					priv->transient = 4;
673 					priv->setup_done = 0;
674 					resubmit = 0;
675 					dev_dbg(&port->dev, "%s(): scheduling setup_line()\n", __func__);
676 					schedule_delayed_work(&priv->delayed_setup_work, 0);
677 				}
678 			}
679 		} else {
680 			if (OTI6858_CTRL_EQUALS_PENDING(xs, priv)) {
681 				priv->transient = 0;
682 			} else if (!priv->setup_done) {
683 				resubmit = 0;
684 			} else if (--priv->transient == 0) {
685 				if (xs->rx_bytes_avail == 0) {
686 					priv->transient = 4;
687 					priv->setup_done = 0;
688 					resubmit = 0;
689 					dev_dbg(&port->dev, "%s(): scheduling setup_line()\n", __func__);
690 					schedule_delayed_work(&priv->delayed_setup_work, 0);
691 				}
692 			}
693 		}
694 
695 		if (!priv->transient) {
696 			u8 delta = xs->pin_state ^ priv->status.pin_state;
697 
698 			if (delta & PIN_MSR_MASK) {
699 				if (delta & PIN_CTS)
700 					port->icount.cts++;
701 				if (delta & PIN_DSR)
702 					port->icount.dsr++;
703 				if (delta & PIN_RI)
704 					port->icount.rng++;
705 				if (delta & PIN_DCD)
706 					port->icount.dcd++;
707 
708 				wake_up_interruptible(&port->port.delta_msr_wait);
709 			}
710 
711 			memcpy(&priv->status, xs, OTI6858_CTRL_PKT_SIZE);
712 		}
713 
714 		if (!priv->transient && xs->rx_bytes_avail != 0) {
715 			can_recv = xs->rx_bytes_avail;
716 			priv->flags.read_urb_in_use = 1;
717 		}
718 
719 		transient = priv->transient;
720 		spin_unlock_irqrestore(&priv->lock, flags);
721 	}
722 
723 	if (can_recv) {
724 		int result;
725 
726 		result = usb_submit_urb(port->read_urb, GFP_ATOMIC);
727 		if (result != 0) {
728 			priv->flags.read_urb_in_use = 0;
729 			dev_err(&port->dev, "%s(): usb_submit_urb() failed,"
730 					" error %d\n", __func__, result);
731 		} else {
732 			resubmit = 0;
733 		}
734 	} else if (!transient) {
735 		unsigned long flags;
736 		int count;
737 
738 		spin_lock_irqsave(&port->lock, flags);
739 		count = kfifo_len(&port->write_fifo);
740 		spin_unlock_irqrestore(&port->lock, flags);
741 
742 		spin_lock_irqsave(&priv->lock, flags);
743 		if (priv->flags.write_urb_in_use == 0 && count != 0) {
744 			schedule_delayed_work(&priv->delayed_write_work, 0);
745 			resubmit = 0;
746 		}
747 		spin_unlock_irqrestore(&priv->lock, flags);
748 	}
749 
750 	if (resubmit) {
751 		int result;
752 
753 /*		dev_dbg(&urb->dev->dev, "%s(): submitting interrupt urb\n", __func__); */
754 		result = usb_submit_urb(urb, GFP_ATOMIC);
755 		if (result != 0) {
756 			dev_err(&urb->dev->dev,
757 					"%s(): usb_submit_urb() failed with"
758 					" error %d\n", __func__, result);
759 		}
760 	}
761 }
762 
763 static void oti6858_read_bulk_callback(struct urb *urb)
764 {
765 	struct usb_serial_port *port =  urb->context;
766 	struct oti6858_private *priv = usb_get_serial_port_data(port);
767 	unsigned char *data = urb->transfer_buffer;
768 	unsigned long flags;
769 	int status = urb->status;
770 	int result;
771 
772 	spin_lock_irqsave(&priv->lock, flags);
773 	priv->flags.read_urb_in_use = 0;
774 	spin_unlock_irqrestore(&priv->lock, flags);
775 
776 	if (status != 0) {
777 		dev_dbg(&urb->dev->dev, "%s(): unable to handle the error, exiting\n", __func__);
778 		return;
779 	}
780 
781 	if (urb->actual_length > 0) {
782 		tty_insert_flip_string(&port->port, data, urb->actual_length);
783 		tty_flip_buffer_push(&port->port);
784 	}
785 
786 	/* schedule the interrupt urb */
787 	result = usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC);
788 	if (result != 0 && result != -EPERM) {
789 		dev_err(&port->dev, "%s(): usb_submit_urb() failed,"
790 				" error %d\n", __func__, result);
791 	}
792 }
793 
794 static void oti6858_write_bulk_callback(struct urb *urb)
795 {
796 	struct usb_serial_port *port =  urb->context;
797 	struct oti6858_private *priv = usb_get_serial_port_data(port);
798 	int status = urb->status;
799 	int result;
800 
801 	switch (status) {
802 	case 0:
803 		/* success */
804 		break;
805 	case -ECONNRESET:
806 	case -ENOENT:
807 	case -ESHUTDOWN:
808 		/* this urb is terminated, clean up */
809 		dev_dbg(&urb->dev->dev, "%s(): urb shutting down with status: %d\n", __func__, status);
810 		priv->flags.write_urb_in_use = 0;
811 		return;
812 	default:
813 		/* error in the urb, so we have to resubmit it */
814 		dev_dbg(&urb->dev->dev, "%s(): nonzero write bulk status received: %d\n", __func__, status);
815 		dev_dbg(&urb->dev->dev, "%s(): overflow in write\n", __func__);
816 
817 		port->write_urb->transfer_buffer_length = 1;
818 		result = usb_submit_urb(port->write_urb, GFP_ATOMIC);
819 		if (result) {
820 			dev_err_console(port, "%s(): usb_submit_urb() failed,"
821 					" error %d\n", __func__, result);
822 		} else {
823 			return;
824 		}
825 	}
826 
827 	priv->flags.write_urb_in_use = 0;
828 
829 	/* schedule the interrupt urb if we are still open */
830 	dev_dbg(&port->dev, "%s(): submitting interrupt urb\n", __func__);
831 	result = usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC);
832 	if (result != 0) {
833 		dev_err(&port->dev, "%s(): failed submitting int urb,"
834 					" error %d\n", __func__, result);
835 	}
836 }
837 
838 module_usb_serial_driver(serial_drivers, id_table);
839 
840 MODULE_DESCRIPTION(OTI6858_DESCRIPTION);
841 MODULE_AUTHOR(OTI6858_AUTHOR);
842 MODULE_LICENSE("GPL v2");
843