xref: /openbmc/linux/drivers/w1/masters/ds2490.c (revision 5d331b7f)
1 /*
2  *	ds2490.c  USB to one wire bridge
3  *
4  * Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
5  *
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License as published by
9  * the Free Software Foundation; either version 2 of the License, or
10  * (at your option) any later version.
11  *
12  * This program is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15  * GNU General Public License for more details.
16  *
17  * You should have received a copy of the GNU General Public License
18  * along with this program; if not, write to the Free Software
19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20  */
21 
22 #include <linux/module.h>
23 #include <linux/kernel.h>
24 #include <linux/mod_devicetable.h>
25 #include <linux/usb.h>
26 #include <linux/slab.h>
27 
28 #include <linux/w1.h>
29 
30 /* USB Standard */
31 /* USB Control request vendor type */
32 #define VENDOR				0x40
33 
34 /* COMMAND TYPE CODES */
35 #define CONTROL_CMD			0x00
36 #define COMM_CMD			0x01
37 #define MODE_CMD			0x02
38 
39 /* CONTROL COMMAND CODES */
40 #define CTL_RESET_DEVICE		0x0000
41 #define CTL_START_EXE			0x0001
42 #define CTL_RESUME_EXE			0x0002
43 #define CTL_HALT_EXE_IDLE		0x0003
44 #define CTL_HALT_EXE_DONE		0x0004
45 #define CTL_FLUSH_COMM_CMDS		0x0007
46 #define CTL_FLUSH_RCV_BUFFER		0x0008
47 #define CTL_FLUSH_XMT_BUFFER		0x0009
48 #define CTL_GET_COMM_CMDS		0x000A
49 
50 /* MODE COMMAND CODES */
51 #define MOD_PULSE_EN			0x0000
52 #define MOD_SPEED_CHANGE_EN		0x0001
53 #define MOD_1WIRE_SPEED			0x0002
54 #define MOD_STRONG_PU_DURATION		0x0003
55 #define MOD_PULLDOWN_SLEWRATE		0x0004
56 #define MOD_PROG_PULSE_DURATION		0x0005
57 #define MOD_WRITE1_LOWTIME		0x0006
58 #define MOD_DSOW0_TREC			0x0007
59 
60 /* COMMUNICATION COMMAND CODES */
61 #define COMM_ERROR_ESCAPE		0x0601
62 #define COMM_SET_DURATION		0x0012
63 #define COMM_BIT_IO			0x0020
64 #define COMM_PULSE			0x0030
65 #define COMM_1_WIRE_RESET		0x0042
66 #define COMM_BYTE_IO			0x0052
67 #define COMM_MATCH_ACCESS		0x0064
68 #define COMM_BLOCK_IO			0x0074
69 #define COMM_READ_STRAIGHT		0x0080
70 #define COMM_DO_RELEASE			0x6092
71 #define COMM_SET_PATH			0x00A2
72 #define COMM_WRITE_SRAM_PAGE		0x00B2
73 #define COMM_WRITE_EPROM		0x00C4
74 #define COMM_READ_CRC_PROT_PAGE		0x00D4
75 #define COMM_READ_REDIRECT_PAGE_CRC	0x21E4
76 #define COMM_SEARCH_ACCESS		0x00F4
77 
78 /* Communication command bits */
79 #define COMM_TYPE			0x0008
80 #define COMM_SE				0x0008
81 #define COMM_D				0x0008
82 #define COMM_Z				0x0008
83 #define COMM_CH				0x0008
84 #define COMM_SM				0x0008
85 #define COMM_R				0x0008
86 #define COMM_IM				0x0001
87 
88 #define COMM_PS				0x4000
89 #define COMM_PST			0x4000
90 #define COMM_CIB			0x4000
91 #define COMM_RTS			0x4000
92 #define COMM_DT				0x2000
93 #define COMM_SPU			0x1000
94 #define COMM_F				0x0800
95 #define COMM_NTF			0x0400
96 #define COMM_ICP			0x0200
97 #define COMM_RST			0x0100
98 
99 #define PULSE_PROG			0x01
100 #define PULSE_SPUE			0x02
101 
102 #define BRANCH_MAIN			0xCC
103 #define BRANCH_AUX			0x33
104 
105 /* Status flags */
106 #define ST_SPUA				0x01  /* Strong Pull-up is active */
107 #define ST_PRGA				0x02  /* 12V programming pulse is being generated */
108 #define ST_12VP				0x04  /* external 12V programming voltage is present */
109 #define ST_PMOD				0x08  /* DS2490 powered from USB and external sources */
110 #define ST_HALT				0x10  /* DS2490 is currently halted */
111 #define ST_IDLE				0x20  /* DS2490 is currently idle */
112 #define ST_EPOF				0x80
113 /* Status transfer size, 16 bytes status, 16 byte result flags */
114 #define ST_SIZE				0x20
115 
116 /* Result Register flags */
117 #define RR_DETECT			0xA5 /* New device detected */
118 #define RR_NRS				0x01 /* Reset no presence or ... */
119 #define RR_SH				0x02 /* short on reset or set path */
120 #define RR_APP				0x04 /* alarming presence on reset */
121 #define RR_VPP				0x08 /* 12V expected not seen */
122 #define RR_CMP				0x10 /* compare error */
123 #define RR_CRC				0x20 /* CRC error detected */
124 #define RR_RDP				0x40 /* redirected page */
125 #define RR_EOS				0x80 /* end of search error */
126 
127 #define SPEED_NORMAL			0x00
128 #define SPEED_FLEXIBLE			0x01
129 #define SPEED_OVERDRIVE			0x02
130 
131 #define NUM_EP				4
132 #define EP_CONTROL			0
133 #define EP_STATUS			1
134 #define EP_DATA_OUT			2
135 #define EP_DATA_IN			3
136 
137 struct ds_device {
138 	struct list_head	ds_entry;
139 
140 	struct usb_device	*udev;
141 	struct usb_interface	*intf;
142 
143 	int			ep[NUM_EP];
144 
145 	/* Strong PullUp
146 	 * 0: pullup not active, else duration in milliseconds
147 	 */
148 	int			spu_sleep;
149 	/* spu_bit contains COMM_SPU or 0 depending on if the strong pullup
150 	 * should be active or not for writes.
151 	 */
152 	u16			spu_bit;
153 
154 	u8			st_buf[ST_SIZE];
155 	u8			byte_buf;
156 
157 	struct w1_bus_master	master;
158 };
159 
160 struct ds_status {
161 	u8			enable;
162 	u8			speed;
163 	u8			pullup_dur;
164 	u8			ppuls_dur;
165 	u8			pulldown_slew;
166 	u8			write1_time;
167 	u8			write0_time;
168 	u8			reserved0;
169 	u8			status;
170 	u8			command0;
171 	u8			command1;
172 	u8			command_buffer_status;
173 	u8			data_out_buffer_status;
174 	u8			data_in_buffer_status;
175 	u8			reserved1;
176 	u8			reserved2;
177 };
178 
179 static LIST_HEAD(ds_devices);
180 static DEFINE_MUTEX(ds_mutex);
181 
182 static int ds_send_control_cmd(struct ds_device *dev, u16 value, u16 index)
183 {
184 	int err;
185 
186 	err = usb_control_msg(dev->udev, usb_sndctrlpipe(dev->udev, dev->ep[EP_CONTROL]),
187 			CONTROL_CMD, VENDOR, value, index, NULL, 0, 1000);
188 	if (err < 0) {
189 		pr_err("Failed to send command control message %x.%x: err=%d.\n",
190 				value, index, err);
191 		return err;
192 	}
193 
194 	return err;
195 }
196 
197 static int ds_send_control_mode(struct ds_device *dev, u16 value, u16 index)
198 {
199 	int err;
200 
201 	err = usb_control_msg(dev->udev, usb_sndctrlpipe(dev->udev, dev->ep[EP_CONTROL]),
202 			MODE_CMD, VENDOR, value, index, NULL, 0, 1000);
203 	if (err < 0) {
204 		pr_err("Failed to send mode control message %x.%x: err=%d.\n",
205 				value, index, err);
206 		return err;
207 	}
208 
209 	return err;
210 }
211 
212 static int ds_send_control(struct ds_device *dev, u16 value, u16 index)
213 {
214 	int err;
215 
216 	err = usb_control_msg(dev->udev, usb_sndctrlpipe(dev->udev, dev->ep[EP_CONTROL]),
217 			COMM_CMD, VENDOR, value, index, NULL, 0, 1000);
218 	if (err < 0) {
219 		pr_err("Failed to send control message %x.%x: err=%d.\n",
220 				value, index, err);
221 		return err;
222 	}
223 
224 	return err;
225 }
226 
227 static inline void ds_print_msg(unsigned char *buf, unsigned char *str, int off)
228 {
229 	pr_info("%45s: %8x\n", str, buf[off]);
230 }
231 
232 static void ds_dump_status(struct ds_device *dev, unsigned char *buf, int count)
233 {
234 	int i;
235 
236 	pr_info("0x%x: count=%d, status: ", dev->ep[EP_STATUS], count);
237 	for (i = 0; i < count; ++i)
238 		pr_info("%02x ", buf[i]);
239 	pr_info("\n");
240 
241 	if (count >= 16) {
242 		ds_print_msg(buf, "enable flag", 0);
243 		ds_print_msg(buf, "1-wire speed", 1);
244 		ds_print_msg(buf, "strong pullup duration", 2);
245 		ds_print_msg(buf, "programming pulse duration", 3);
246 		ds_print_msg(buf, "pulldown slew rate control", 4);
247 		ds_print_msg(buf, "write-1 low time", 5);
248 		ds_print_msg(buf, "data sample offset/write-0 recovery time",
249 			6);
250 		ds_print_msg(buf, "reserved (test register)", 7);
251 		ds_print_msg(buf, "device status flags", 8);
252 		ds_print_msg(buf, "communication command byte 1", 9);
253 		ds_print_msg(buf, "communication command byte 2", 10);
254 		ds_print_msg(buf, "communication command buffer status", 11);
255 		ds_print_msg(buf, "1-wire data output buffer status", 12);
256 		ds_print_msg(buf, "1-wire data input buffer status", 13);
257 		ds_print_msg(buf, "reserved", 14);
258 		ds_print_msg(buf, "reserved", 15);
259 	}
260 	for (i = 16; i < count; ++i) {
261 		if (buf[i] == RR_DETECT) {
262 			ds_print_msg(buf, "new device detect", i);
263 			continue;
264 		}
265 		ds_print_msg(buf, "Result Register Value: ", i);
266 		if (buf[i] & RR_NRS)
267 			pr_info("NRS: Reset no presence or ...\n");
268 		if (buf[i] & RR_SH)
269 			pr_info("SH: short on reset or set path\n");
270 		if (buf[i] & RR_APP)
271 			pr_info("APP: alarming presence on reset\n");
272 		if (buf[i] & RR_VPP)
273 			pr_info("VPP: 12V expected not seen\n");
274 		if (buf[i] & RR_CMP)
275 			pr_info("CMP: compare error\n");
276 		if (buf[i] & RR_CRC)
277 			pr_info("CRC: CRC error detected\n");
278 		if (buf[i] & RR_RDP)
279 			pr_info("RDP: redirected page\n");
280 		if (buf[i] & RR_EOS)
281 			pr_info("EOS: end of search error\n");
282 	}
283 }
284 
285 static int ds_recv_status(struct ds_device *dev, struct ds_status *st,
286 			  bool dump)
287 {
288 	int count, err;
289 
290 	if (st)
291 		memset(st, 0, sizeof(*st));
292 
293 	count = 0;
294 	err = usb_interrupt_msg(dev->udev,
295 				usb_rcvintpipe(dev->udev,
296 					       dev->ep[EP_STATUS]),
297 				dev->st_buf, sizeof(dev->st_buf),
298 				&count, 1000);
299 	if (err < 0) {
300 		pr_err("Failed to read 1-wire data from 0x%x: err=%d.\n",
301 		       dev->ep[EP_STATUS], err);
302 		return err;
303 	}
304 
305 	if (dump)
306 		ds_dump_status(dev, dev->st_buf, count);
307 
308 	if (st && count >= sizeof(*st))
309 		memcpy(st, dev->st_buf, sizeof(*st));
310 
311 	return count;
312 }
313 
314 static void ds_reset_device(struct ds_device *dev)
315 {
316 	ds_send_control_cmd(dev, CTL_RESET_DEVICE, 0);
317 	/* Always allow strong pullup which allow individual writes to use
318 	 * the strong pullup.
319 	 */
320 	if (ds_send_control_mode(dev, MOD_PULSE_EN, PULSE_SPUE))
321 		pr_err("ds_reset_device: Error allowing strong pullup\n");
322 	/* Chip strong pullup time was cleared. */
323 	if (dev->spu_sleep) {
324 		/* lower 4 bits are 0, see ds_set_pullup */
325 		u8 del = dev->spu_sleep>>4;
326 		if (ds_send_control(dev, COMM_SET_DURATION | COMM_IM, del))
327 			pr_err("ds_reset_device: Error setting duration\n");
328 	}
329 }
330 
331 static int ds_recv_data(struct ds_device *dev, unsigned char *buf, int size)
332 {
333 	int count, err;
334 
335 	/* Careful on size.  If size is less than what is available in
336 	 * the input buffer, the device fails the bulk transfer and
337 	 * clears the input buffer.  It could read the maximum size of
338 	 * the data buffer, but then do you return the first, last, or
339 	 * some set of the middle size bytes?  As long as the rest of
340 	 * the code is correct there will be size bytes waiting.  A
341 	 * call to ds_wait_status will wait until the device is idle
342 	 * and any data to be received would have been available.
343 	 */
344 	count = 0;
345 	err = usb_bulk_msg(dev->udev, usb_rcvbulkpipe(dev->udev, dev->ep[EP_DATA_IN]),
346 				buf, size, &count, 1000);
347 	if (err < 0) {
348 		pr_info("Clearing ep0x%x.\n", dev->ep[EP_DATA_IN]);
349 		usb_clear_halt(dev->udev, usb_rcvbulkpipe(dev->udev, dev->ep[EP_DATA_IN]));
350 		ds_recv_status(dev, NULL, true);
351 		return err;
352 	}
353 
354 #if 0
355 	{
356 		int i;
357 
358 		printk("%s: count=%d: ", __func__, count);
359 		for (i = 0; i < count; ++i)
360 			printk("%02x ", buf[i]);
361 		printk("\n");
362 	}
363 #endif
364 	return count;
365 }
366 
367 static int ds_send_data(struct ds_device *dev, unsigned char *buf, int len)
368 {
369 	int count, err;
370 
371 	count = 0;
372 	err = usb_bulk_msg(dev->udev, usb_sndbulkpipe(dev->udev, dev->ep[EP_DATA_OUT]), buf, len, &count, 1000);
373 	if (err < 0) {
374 		pr_err("Failed to write 1-wire data to ep0x%x: "
375 			"err=%d.\n", dev->ep[EP_DATA_OUT], err);
376 		return err;
377 	}
378 
379 	return err;
380 }
381 
382 #if 0
383 
384 int ds_stop_pulse(struct ds_device *dev, int limit)
385 {
386 	struct ds_status st;
387 	int count = 0, err = 0;
388 
389 	do {
390 		err = ds_send_control(dev, CTL_HALT_EXE_IDLE, 0);
391 		if (err)
392 			break;
393 		err = ds_send_control(dev, CTL_RESUME_EXE, 0);
394 		if (err)
395 			break;
396 		err = ds_recv_status(dev, &st, false);
397 		if (err)
398 			break;
399 
400 		if ((st.status & ST_SPUA) == 0) {
401 			err = ds_send_control_mode(dev, MOD_PULSE_EN, 0);
402 			if (err)
403 				break;
404 		}
405 	} while (++count < limit);
406 
407 	return err;
408 }
409 
410 int ds_detect(struct ds_device *dev, struct ds_status *st)
411 {
412 	int err;
413 
414 	err = ds_send_control_cmd(dev, CTL_RESET_DEVICE, 0);
415 	if (err)
416 		return err;
417 
418 	err = ds_send_control(dev, COMM_SET_DURATION | COMM_IM, 0);
419 	if (err)
420 		return err;
421 
422 	err = ds_send_control(dev, COMM_SET_DURATION | COMM_IM | COMM_TYPE, 0x40);
423 	if (err)
424 		return err;
425 
426 	err = ds_send_control_mode(dev, MOD_PULSE_EN, PULSE_PROG);
427 	if (err)
428 		return err;
429 
430 	err = ds_dump_status(dev, st);
431 
432 	return err;
433 }
434 
435 #endif  /*  0  */
436 
437 static int ds_wait_status(struct ds_device *dev, struct ds_status *st)
438 {
439 	int err, count = 0;
440 
441 	do {
442 		st->status = 0;
443 		err = ds_recv_status(dev, st, false);
444 #if 0
445 		if (err >= 0) {
446 			int i;
447 			printk("0x%x: count=%d, status: ", dev->ep[EP_STATUS], err);
448 			for (i = 0; i < err; ++i)
449 				printk("%02x ", dev->st_buf[i]);
450 			printk("\n");
451 		}
452 #endif
453 	} while (!(st->status & ST_IDLE) && !(err < 0) && ++count < 100);
454 
455 	if (err >= 16 && st->status & ST_EPOF) {
456 		pr_info("Resetting device after ST_EPOF.\n");
457 		ds_reset_device(dev);
458 		/* Always dump the device status. */
459 		count = 101;
460 	}
461 
462 	/* Dump the status for errors or if there is extended return data.
463 	 * The extended status includes new device detection (maybe someone
464 	 * can do something with it).
465 	 */
466 	if (err > 16 || count >= 100 || err < 0)
467 		ds_dump_status(dev, dev->st_buf, err);
468 
469 	/* Extended data isn't an error.  Well, a short is, but the dump
470 	 * would have already told the user that and we can't do anything
471 	 * about it in software anyway.
472 	 */
473 	if (count >= 100 || err < 0)
474 		return -1;
475 	else
476 		return 0;
477 }
478 
479 static int ds_reset(struct ds_device *dev)
480 {
481 	int err;
482 
483 	/* Other potentionally interesting flags for reset.
484 	 *
485 	 * COMM_NTF: Return result register feedback.  This could be used to
486 	 * detect some conditions such as short, alarming presence, or
487 	 * detect if a new device was detected.
488 	 *
489 	 * COMM_SE which allows SPEED_NORMAL, SPEED_FLEXIBLE, SPEED_OVERDRIVE:
490 	 * Select the data transfer rate.
491 	 */
492 	err = ds_send_control(dev, COMM_1_WIRE_RESET | COMM_IM, SPEED_NORMAL);
493 	if (err)
494 		return err;
495 
496 	return 0;
497 }
498 
499 #if 0
500 static int ds_set_speed(struct ds_device *dev, int speed)
501 {
502 	int err;
503 
504 	if (speed != SPEED_NORMAL && speed != SPEED_FLEXIBLE && speed != SPEED_OVERDRIVE)
505 		return -EINVAL;
506 
507 	if (speed != SPEED_OVERDRIVE)
508 		speed = SPEED_FLEXIBLE;
509 
510 	speed &= 0xff;
511 
512 	err = ds_send_control_mode(dev, MOD_1WIRE_SPEED, speed);
513 	if (err)
514 		return err;
515 
516 	return err;
517 }
518 #endif  /*  0  */
519 
520 static int ds_set_pullup(struct ds_device *dev, int delay)
521 {
522 	int err = 0;
523 	u8 del = 1 + (u8)(delay >> 4);
524 	/* Just storing delay would not get the trunication and roundup. */
525 	int ms = del<<4;
526 
527 	/* Enable spu_bit if a delay is set. */
528 	dev->spu_bit = delay ? COMM_SPU : 0;
529 	/* If delay is zero, it has already been disabled, if the time is
530 	 * the same as the hardware was last programmed to, there is also
531 	 * nothing more to do.  Compare with the recalculated value ms
532 	 * rather than del or delay which can have a different value.
533 	 */
534 	if (delay == 0 || ms == dev->spu_sleep)
535 		return err;
536 
537 	err = ds_send_control(dev, COMM_SET_DURATION | COMM_IM, del);
538 	if (err)
539 		return err;
540 
541 	dev->spu_sleep = ms;
542 
543 	return err;
544 }
545 
546 static int ds_touch_bit(struct ds_device *dev, u8 bit, u8 *tbit)
547 {
548 	int err;
549 	struct ds_status st;
550 
551 	err = ds_send_control(dev, COMM_BIT_IO | COMM_IM | (bit ? COMM_D : 0),
552 		0);
553 	if (err)
554 		return err;
555 
556 	ds_wait_status(dev, &st);
557 
558 	err = ds_recv_data(dev, tbit, sizeof(*tbit));
559 	if (err < 0)
560 		return err;
561 
562 	return 0;
563 }
564 
565 #if 0
566 static int ds_write_bit(struct ds_device *dev, u8 bit)
567 {
568 	int err;
569 	struct ds_status st;
570 
571 	/* Set COMM_ICP to write without a readback.  Note, this will
572 	 * produce one time slot, a down followed by an up with COMM_D
573 	 * only determing the timing.
574 	 */
575 	err = ds_send_control(dev, COMM_BIT_IO | COMM_IM | COMM_ICP |
576 		(bit ? COMM_D : 0), 0);
577 	if (err)
578 		return err;
579 
580 	ds_wait_status(dev, &st);
581 
582 	return 0;
583 }
584 #endif
585 
586 static int ds_write_byte(struct ds_device *dev, u8 byte)
587 {
588 	int err;
589 	struct ds_status st;
590 
591 	err = ds_send_control(dev, COMM_BYTE_IO | COMM_IM | dev->spu_bit, byte);
592 	if (err)
593 		return err;
594 
595 	if (dev->spu_bit)
596 		msleep(dev->spu_sleep);
597 
598 	err = ds_wait_status(dev, &st);
599 	if (err)
600 		return err;
601 
602 	err = ds_recv_data(dev, &dev->byte_buf, 1);
603 	if (err < 0)
604 		return err;
605 
606 	return !(byte == dev->byte_buf);
607 }
608 
609 static int ds_read_byte(struct ds_device *dev, u8 *byte)
610 {
611 	int err;
612 	struct ds_status st;
613 
614 	err = ds_send_control(dev, COMM_BYTE_IO | COMM_IM, 0xff);
615 	if (err)
616 		return err;
617 
618 	ds_wait_status(dev, &st);
619 
620 	err = ds_recv_data(dev, byte, sizeof(*byte));
621 	if (err < 0)
622 		return err;
623 
624 	return 0;
625 }
626 
627 static int ds_read_block(struct ds_device *dev, u8 *buf, int len)
628 {
629 	struct ds_status st;
630 	int err;
631 
632 	if (len > 64*1024)
633 		return -E2BIG;
634 
635 	memset(buf, 0xFF, len);
636 
637 	err = ds_send_data(dev, buf, len);
638 	if (err < 0)
639 		return err;
640 
641 	err = ds_send_control(dev, COMM_BLOCK_IO | COMM_IM, len);
642 	if (err)
643 		return err;
644 
645 	ds_wait_status(dev, &st);
646 
647 	memset(buf, 0x00, len);
648 	err = ds_recv_data(dev, buf, len);
649 
650 	return err;
651 }
652 
653 static int ds_write_block(struct ds_device *dev, u8 *buf, int len)
654 {
655 	int err;
656 	struct ds_status st;
657 
658 	err = ds_send_data(dev, buf, len);
659 	if (err < 0)
660 		return err;
661 
662 	err = ds_send_control(dev, COMM_BLOCK_IO | COMM_IM | dev->spu_bit, len);
663 	if (err)
664 		return err;
665 
666 	if (dev->spu_bit)
667 		msleep(dev->spu_sleep);
668 
669 	ds_wait_status(dev, &st);
670 
671 	err = ds_recv_data(dev, buf, len);
672 	if (err < 0)
673 		return err;
674 
675 	return !(err == len);
676 }
677 
678 static void ds9490r_search(void *data, struct w1_master *master,
679 	u8 search_type, w1_slave_found_callback callback)
680 {
681 	/* When starting with an existing id, the first id returned will
682 	 * be that device (if it is still on the bus most likely).
683 	 *
684 	 * If the number of devices found is less than or equal to the
685 	 * search_limit, that number of IDs will be returned.  If there are
686 	 * more, search_limit IDs will be returned followed by a non-zero
687 	 * discrepency value.
688 	 */
689 	struct ds_device *dev = data;
690 	int err;
691 	u16 value, index;
692 	struct ds_status st;
693 	int search_limit;
694 	int found = 0;
695 	int i;
696 
697 	/* DS18b20 spec, 13.16 ms per device, 75 per second, sleep for
698 	 * discovering 8 devices (1 bulk transfer and 1/2 FIFO size) at a time.
699 	 */
700 	const unsigned long jtime = msecs_to_jiffies(1000*8/75);
701 	/* FIFO 128 bytes, bulk packet size 64, read a multiple of the
702 	 * packet size.
703 	 */
704 	const size_t bufsize = 2 * 64;
705 	u64 *buf;
706 
707 	buf = kmalloc(bufsize, GFP_KERNEL);
708 	if (!buf)
709 		return;
710 
711 	mutex_lock(&master->bus_mutex);
712 
713 	/* address to start searching at */
714 	if (ds_send_data(dev, (u8 *)&master->search_id, 8) < 0)
715 		goto search_out;
716 	master->search_id = 0;
717 
718 	value = COMM_SEARCH_ACCESS | COMM_IM | COMM_RST | COMM_SM | COMM_F |
719 		COMM_RTS;
720 	search_limit = master->max_slave_count;
721 	if (search_limit > 255)
722 		search_limit = 0;
723 	index = search_type | (search_limit << 8);
724 	if (ds_send_control(dev, value, index) < 0)
725 		goto search_out;
726 
727 	do {
728 		schedule_timeout(jtime);
729 
730 		err = ds_recv_status(dev, &st, false);
731 		if (err < 0 || err < sizeof(st))
732 			break;
733 
734 		if (st.data_in_buffer_status) {
735 			/* Bulk in can receive partial ids, but when it does
736 			 * they fail crc and will be discarded anyway.
737 			 * That has only been seen when status in buffer
738 			 * is 0 and bulk is read anyway, so don't read
739 			 * bulk without first checking if status says there
740 			 * is data to read.
741 			 */
742 			err = ds_recv_data(dev, (u8 *)buf, bufsize);
743 			if (err < 0)
744 				break;
745 			for (i = 0; i < err/8; ++i) {
746 				++found;
747 				if (found <= search_limit)
748 					callback(master, buf[i]);
749 				/* can't know if there will be a discrepancy
750 				 * value after until the next id */
751 				if (found == search_limit)
752 					master->search_id = buf[i];
753 			}
754 		}
755 
756 		if (test_bit(W1_ABORT_SEARCH, &master->flags))
757 			break;
758 	} while (!(st.status & (ST_IDLE | ST_HALT)));
759 
760 	/* only continue the search if some weren't found */
761 	if (found <= search_limit) {
762 		master->search_id = 0;
763 	} else if (!test_bit(W1_WARN_MAX_COUNT, &master->flags)) {
764 		/* Only max_slave_count will be scanned in a search,
765 		 * but it will start where it left off next search
766 		 * until all ids are identified and then it will start
767 		 * over.  A continued search will report the previous
768 		 * last id as the first id (provided it is still on the
769 		 * bus).
770 		 */
771 		dev_info(&dev->udev->dev, "%s: max_slave_count %d reached, "
772 			"will continue next search.\n", __func__,
773 			master->max_slave_count);
774 		set_bit(W1_WARN_MAX_COUNT, &master->flags);
775 	}
776 search_out:
777 	mutex_unlock(&master->bus_mutex);
778 	kfree(buf);
779 }
780 
781 #if 0
782 /*
783  * FIXME: if this disabled code is ever used in the future all ds_send_data()
784  * calls must be changed to use a DMAable buffer.
785  */
786 static int ds_match_access(struct ds_device *dev, u64 init)
787 {
788 	int err;
789 	struct ds_status st;
790 
791 	err = ds_send_data(dev, (unsigned char *)&init, sizeof(init));
792 	if (err)
793 		return err;
794 
795 	ds_wait_status(dev, &st);
796 
797 	err = ds_send_control(dev, COMM_MATCH_ACCESS | COMM_IM | COMM_RST, 0x0055);
798 	if (err)
799 		return err;
800 
801 	ds_wait_status(dev, &st);
802 
803 	return 0;
804 }
805 
806 static int ds_set_path(struct ds_device *dev, u64 init)
807 {
808 	int err;
809 	struct ds_status st;
810 	u8 buf[9];
811 
812 	memcpy(buf, &init, 8);
813 	buf[8] = BRANCH_MAIN;
814 
815 	err = ds_send_data(dev, buf, sizeof(buf));
816 	if (err)
817 		return err;
818 
819 	ds_wait_status(dev, &st);
820 
821 	err = ds_send_control(dev, COMM_SET_PATH | COMM_IM | COMM_RST, 0);
822 	if (err)
823 		return err;
824 
825 	ds_wait_status(dev, &st);
826 
827 	return 0;
828 }
829 
830 #endif  /*  0  */
831 
832 static u8 ds9490r_touch_bit(void *data, u8 bit)
833 {
834 	struct ds_device *dev = data;
835 
836 	if (ds_touch_bit(dev, bit, &dev->byte_buf))
837 		return 0;
838 
839 	return dev->byte_buf;
840 }
841 
842 #if 0
843 static void ds9490r_write_bit(void *data, u8 bit)
844 {
845 	struct ds_device *dev = data;
846 
847 	ds_write_bit(dev, bit);
848 }
849 
850 static u8 ds9490r_read_bit(void *data)
851 {
852 	struct ds_device *dev = data;
853 	int err;
854 
855 	err = ds_touch_bit(dev, 1, &dev->byte_buf);
856 	if (err)
857 		return 0;
858 
859 	return dev->byte_buf & 1;
860 }
861 #endif
862 
863 static void ds9490r_write_byte(void *data, u8 byte)
864 {
865 	struct ds_device *dev = data;
866 
867 	ds_write_byte(dev, byte);
868 }
869 
870 static u8 ds9490r_read_byte(void *data)
871 {
872 	struct ds_device *dev = data;
873 	int err;
874 
875 	err = ds_read_byte(dev, &dev->byte_buf);
876 	if (err)
877 		return 0;
878 
879 	return dev->byte_buf;
880 }
881 
882 static void ds9490r_write_block(void *data, const u8 *buf, int len)
883 {
884 	struct ds_device *dev = data;
885 	u8 *tbuf;
886 
887 	if (len <= 0)
888 		return;
889 
890 	tbuf = kmemdup(buf, len, GFP_KERNEL);
891 	if (!tbuf)
892 		return;
893 
894 	ds_write_block(dev, tbuf, len);
895 
896 	kfree(tbuf);
897 }
898 
899 static u8 ds9490r_read_block(void *data, u8 *buf, int len)
900 {
901 	struct ds_device *dev = data;
902 	int err;
903 	u8 *tbuf;
904 
905 	if (len <= 0)
906 		return 0;
907 
908 	tbuf = kmalloc(len, GFP_KERNEL);
909 	if (!tbuf)
910 		return 0;
911 
912 	err = ds_read_block(dev, tbuf, len);
913 	if (err >= 0)
914 		memcpy(buf, tbuf, len);
915 
916 	kfree(tbuf);
917 
918 	return err >= 0 ? len : 0;
919 }
920 
921 static u8 ds9490r_reset(void *data)
922 {
923 	struct ds_device *dev = data;
924 	int err;
925 
926 	err = ds_reset(dev);
927 	if (err)
928 		return 1;
929 
930 	return 0;
931 }
932 
933 static u8 ds9490r_set_pullup(void *data, int delay)
934 {
935 	struct ds_device *dev = data;
936 
937 	if (ds_set_pullup(dev, delay))
938 		return 1;
939 
940 	return 0;
941 }
942 
943 static int ds_w1_init(struct ds_device *dev)
944 {
945 	memset(&dev->master, 0, sizeof(struct w1_bus_master));
946 
947 	/* Reset the device as it can be in a bad state.
948 	 * This is necessary because a block write will wait for data
949 	 * to be placed in the output buffer and block any later
950 	 * commands which will keep accumulating and the device will
951 	 * not be idle.  Another case is removing the ds2490 module
952 	 * while a bus search is in progress, somehow a few commands
953 	 * get through, but the input transfers fail leaving data in
954 	 * the input buffer.  This will cause the next read to fail
955 	 * see the note in ds_recv_data.
956 	 */
957 	ds_reset_device(dev);
958 
959 	dev->master.data	= dev;
960 	dev->master.touch_bit	= &ds9490r_touch_bit;
961 	/* read_bit and write_bit in w1_bus_master are expected to set and
962 	 * sample the line level.  For write_bit that means it is expected to
963 	 * set it to that value and leave it there.  ds2490 only supports an
964 	 * individual time slot at the lowest level.  The requirement from
965 	 * pulling the bus state down to reading the state is 15us, something
966 	 * that isn't realistic on the USB bus anyway.
967 	dev->master.read_bit	= &ds9490r_read_bit;
968 	dev->master.write_bit	= &ds9490r_write_bit;
969 	*/
970 	dev->master.read_byte	= &ds9490r_read_byte;
971 	dev->master.write_byte	= &ds9490r_write_byte;
972 	dev->master.read_block	= &ds9490r_read_block;
973 	dev->master.write_block	= &ds9490r_write_block;
974 	dev->master.reset_bus	= &ds9490r_reset;
975 	dev->master.set_pullup	= &ds9490r_set_pullup;
976 	dev->master.search	= &ds9490r_search;
977 
978 	return w1_add_master_device(&dev->master);
979 }
980 
981 static void ds_w1_fini(struct ds_device *dev)
982 {
983 	w1_remove_master_device(&dev->master);
984 }
985 
986 static int ds_probe(struct usb_interface *intf,
987 		    const struct usb_device_id *udev_id)
988 {
989 	struct usb_device *udev = interface_to_usbdev(intf);
990 	struct usb_endpoint_descriptor *endpoint;
991 	struct usb_host_interface *iface_desc;
992 	struct ds_device *dev;
993 	int i, err, alt;
994 
995 	dev = kzalloc(sizeof(struct ds_device), GFP_KERNEL);
996 	if (!dev) {
997 		pr_info("Failed to allocate new DS9490R structure.\n");
998 		return -ENOMEM;
999 	}
1000 	dev->udev = usb_get_dev(udev);
1001 	if (!dev->udev) {
1002 		err = -ENOMEM;
1003 		goto err_out_free;
1004 	}
1005 	memset(dev->ep, 0, sizeof(dev->ep));
1006 
1007 	usb_set_intfdata(intf, dev);
1008 
1009 	err = usb_reset_configuration(dev->udev);
1010 	if (err) {
1011 		dev_err(&dev->udev->dev,
1012 			"Failed to reset configuration: err=%d.\n", err);
1013 		goto err_out_clear;
1014 	}
1015 
1016 	/* alternative 3, 1ms interrupt (greatly speeds search), 64 byte bulk */
1017 	alt = 3;
1018 	err = usb_set_interface(dev->udev,
1019 		intf->altsetting[alt].desc.bInterfaceNumber, alt);
1020 	if (err) {
1021 		dev_err(&dev->udev->dev, "Failed to set alternative setting %d "
1022 			"for %d interface: err=%d.\n", alt,
1023 			intf->altsetting[alt].desc.bInterfaceNumber, err);
1024 		goto err_out_clear;
1025 	}
1026 
1027 	iface_desc = &intf->altsetting[alt];
1028 	if (iface_desc->desc.bNumEndpoints != NUM_EP-1) {
1029 		pr_info("Num endpoints=%d. It is not DS9490R.\n",
1030 			iface_desc->desc.bNumEndpoints);
1031 		err = -EINVAL;
1032 		goto err_out_clear;
1033 	}
1034 
1035 	/*
1036 	 * This loop doesn'd show control 0 endpoint,
1037 	 * so we will fill only 1-3 endpoints entry.
1038 	 */
1039 	for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
1040 		endpoint = &iface_desc->endpoint[i].desc;
1041 
1042 		dev->ep[i+1] = endpoint->bEndpointAddress;
1043 #if 0
1044 		printk("%d: addr=%x, size=%d, dir=%s, type=%x\n",
1045 			i, endpoint->bEndpointAddress, le16_to_cpu(endpoint->wMaxPacketSize),
1046 			(endpoint->bEndpointAddress & USB_DIR_IN)?"IN":"OUT",
1047 			endpoint->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK);
1048 #endif
1049 	}
1050 
1051 	err = ds_w1_init(dev);
1052 	if (err)
1053 		goto err_out_clear;
1054 
1055 	mutex_lock(&ds_mutex);
1056 	list_add_tail(&dev->ds_entry, &ds_devices);
1057 	mutex_unlock(&ds_mutex);
1058 
1059 	return 0;
1060 
1061 err_out_clear:
1062 	usb_set_intfdata(intf, NULL);
1063 	usb_put_dev(dev->udev);
1064 err_out_free:
1065 	kfree(dev);
1066 	return err;
1067 }
1068 
1069 static void ds_disconnect(struct usb_interface *intf)
1070 {
1071 	struct ds_device *dev;
1072 
1073 	dev = usb_get_intfdata(intf);
1074 	if (!dev)
1075 		return;
1076 
1077 	mutex_lock(&ds_mutex);
1078 	list_del(&dev->ds_entry);
1079 	mutex_unlock(&ds_mutex);
1080 
1081 	ds_w1_fini(dev);
1082 
1083 	usb_set_intfdata(intf, NULL);
1084 
1085 	usb_put_dev(dev->udev);
1086 	kfree(dev);
1087 }
1088 
1089 static const struct usb_device_id ds_id_table[] = {
1090 	{ USB_DEVICE(0x04fa, 0x2490) },
1091 	{ },
1092 };
1093 MODULE_DEVICE_TABLE(usb, ds_id_table);
1094 
1095 static struct usb_driver ds_driver = {
1096 	.name =		"DS9490R",
1097 	.probe =	ds_probe,
1098 	.disconnect =	ds_disconnect,
1099 	.id_table =	ds_id_table,
1100 };
1101 module_usb_driver(ds_driver);
1102 
1103 MODULE_AUTHOR("Evgeniy Polyakov <zbr@ioremap.net>");
1104 MODULE_DESCRIPTION("DS2490 USB <-> W1 bus master driver (DS9490*)");
1105 MODULE_LICENSE("GPL");
1106