xref: /openbmc/linux/drivers/w1/masters/ds2490.c (revision d2ba09c1)
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 {
139 	struct list_head	ds_entry;
140 
141 	struct usb_device	*udev;
142 	struct usb_interface	*intf;
143 
144 	int			ep[NUM_EP];
145 
146 	/* Strong PullUp
147 	 * 0: pullup not active, else duration in milliseconds
148 	 */
149 	int			spu_sleep;
150 	/* spu_bit contains COMM_SPU or 0 depending on if the strong pullup
151 	 * should be active or not for writes.
152 	 */
153 	u16			spu_bit;
154 
155 	u8			st_buf[ST_SIZE];
156 	u8			byte_buf;
157 
158 	struct w1_bus_master	master;
159 };
160 
161 struct ds_status
162 {
163 	u8			enable;
164 	u8			speed;
165 	u8			pullup_dur;
166 	u8			ppuls_dur;
167 	u8			pulldown_slew;
168 	u8			write1_time;
169 	u8			write0_time;
170 	u8			reserved0;
171 	u8			status;
172 	u8			command0;
173 	u8			command1;
174 	u8			command_buffer_status;
175 	u8			data_out_buffer_status;
176 	u8			data_in_buffer_status;
177 	u8			reserved1;
178 	u8			reserved2;
179 };
180 
181 static LIST_HEAD(ds_devices);
182 static DEFINE_MUTEX(ds_mutex);
183 
184 static int ds_send_control_cmd(struct ds_device *dev, u16 value, u16 index)
185 {
186 	int err;
187 
188 	err = usb_control_msg(dev->udev, usb_sndctrlpipe(dev->udev, dev->ep[EP_CONTROL]),
189 			CONTROL_CMD, VENDOR, value, index, NULL, 0, 1000);
190 	if (err < 0) {
191 		pr_err("Failed to send command control message %x.%x: err=%d.\n",
192 				value, index, err);
193 		return err;
194 	}
195 
196 	return err;
197 }
198 
199 static int ds_send_control_mode(struct ds_device *dev, u16 value, u16 index)
200 {
201 	int err;
202 
203 	err = usb_control_msg(dev->udev, usb_sndctrlpipe(dev->udev, dev->ep[EP_CONTROL]),
204 			MODE_CMD, VENDOR, value, index, NULL, 0, 1000);
205 	if (err < 0) {
206 		pr_err("Failed to send mode control message %x.%x: err=%d.\n",
207 				value, index, err);
208 		return err;
209 	}
210 
211 	return err;
212 }
213 
214 static int ds_send_control(struct ds_device *dev, u16 value, u16 index)
215 {
216 	int err;
217 
218 	err = usb_control_msg(dev->udev, usb_sndctrlpipe(dev->udev, dev->ep[EP_CONTROL]),
219 			COMM_CMD, VENDOR, value, index, NULL, 0, 1000);
220 	if (err < 0) {
221 		pr_err("Failed to send control message %x.%x: err=%d.\n",
222 				value, index, err);
223 		return err;
224 	}
225 
226 	return err;
227 }
228 
229 static inline void ds_print_msg(unsigned char *buf, unsigned char *str, int off)
230 {
231 	pr_info("%45s: %8x\n", str, buf[off]);
232 }
233 
234 static void ds_dump_status(struct ds_device *dev, unsigned char *buf, int count)
235 {
236 	int i;
237 
238 	pr_info("0x%x: count=%d, status: ", dev->ep[EP_STATUS], count);
239 	for (i=0; i<count; ++i)
240 		pr_info("%02x ", buf[i]);
241 	pr_info("\n");
242 
243 	if (count >= 16) {
244 		ds_print_msg(buf, "enable flag", 0);
245 		ds_print_msg(buf, "1-wire speed", 1);
246 		ds_print_msg(buf, "strong pullup duration", 2);
247 		ds_print_msg(buf, "programming pulse duration", 3);
248 		ds_print_msg(buf, "pulldown slew rate control", 4);
249 		ds_print_msg(buf, "write-1 low time", 5);
250 		ds_print_msg(buf, "data sample offset/write-0 recovery time",
251 			6);
252 		ds_print_msg(buf, "reserved (test register)", 7);
253 		ds_print_msg(buf, "device status flags", 8);
254 		ds_print_msg(buf, "communication command byte 1", 9);
255 		ds_print_msg(buf, "communication command byte 2", 10);
256 		ds_print_msg(buf, "communication command buffer status", 11);
257 		ds_print_msg(buf, "1-wire data output buffer status", 12);
258 		ds_print_msg(buf, "1-wire data input buffer status", 13);
259 		ds_print_msg(buf, "reserved", 14);
260 		ds_print_msg(buf, "reserved", 15);
261 	}
262 	for (i = 16; i < count; ++i) {
263 		if (buf[i] == RR_DETECT) {
264 			ds_print_msg(buf, "new device detect", i);
265 			continue;
266 		}
267 		ds_print_msg(buf, "Result Register Value: ", i);
268 		if (buf[i] & RR_NRS)
269 			pr_info("NRS: Reset no presence or ...\n");
270 		if (buf[i] & RR_SH)
271 			pr_info("SH: short on reset or set path\n");
272 		if (buf[i] & RR_APP)
273 			pr_info("APP: alarming presence on reset\n");
274 		if (buf[i] & RR_VPP)
275 			pr_info("VPP: 12V expected not seen\n");
276 		if (buf[i] & RR_CMP)
277 			pr_info("CMP: compare error\n");
278 		if (buf[i] & RR_CRC)
279 			pr_info("CRC: CRC error detected\n");
280 		if (buf[i] & RR_RDP)
281 			pr_info("RDP: redirected page\n");
282 		if (buf[i] & RR_EOS)
283 			pr_info("EOS: end of search error\n");
284 	}
285 }
286 
287 static int ds_recv_status(struct ds_device *dev, struct ds_status *st,
288 			  bool dump)
289 {
290 	int count, err;
291 
292 	if (st)
293 		memset(st, 0, sizeof(*st));
294 
295 	count = 0;
296 	err = usb_interrupt_msg(dev->udev,
297 				usb_rcvintpipe(dev->udev,
298 					       dev->ep[EP_STATUS]),
299 				dev->st_buf, sizeof(dev->st_buf),
300 				&count, 1000);
301 	if (err < 0) {
302 		pr_err("Failed to read 1-wire data from 0x%x: err=%d.\n",
303 		       dev->ep[EP_STATUS], err);
304 		return err;
305 	}
306 
307 	if (dump)
308 		ds_dump_status(dev, dev->st_buf, count);
309 
310 	if (st && count >= sizeof(*st))
311 		memcpy(st, dev->st_buf, sizeof(*st));
312 
313 	return count;
314 }
315 
316 static void ds_reset_device(struct ds_device *dev)
317 {
318 	ds_send_control_cmd(dev, CTL_RESET_DEVICE, 0);
319 	/* Always allow strong pullup which allow individual writes to use
320 	 * the strong pullup.
321 	 */
322 	if (ds_send_control_mode(dev, MOD_PULSE_EN, PULSE_SPUE))
323 		pr_err("ds_reset_device: Error allowing strong pullup\n");
324 	/* Chip strong pullup time was cleared. */
325 	if (dev->spu_sleep) {
326 		/* lower 4 bits are 0, see ds_set_pullup */
327 		u8 del = dev->spu_sleep>>4;
328 		if (ds_send_control(dev, COMM_SET_DURATION | COMM_IM, del))
329 			pr_err("ds_reset_device: Error setting duration\n");
330 	}
331 }
332 
333 static int ds_recv_data(struct ds_device *dev, unsigned char *buf, int size)
334 {
335 	int count, err;
336 
337 	/* Careful on size.  If size is less than what is available in
338 	 * the input buffer, the device fails the bulk transfer and
339 	 * clears the input buffer.  It could read the maximum size of
340 	 * the data buffer, but then do you return the first, last, or
341 	 * some set of the middle size bytes?  As long as the rest of
342 	 * the code is correct there will be size bytes waiting.  A
343 	 * call to ds_wait_status will wait until the device is idle
344 	 * and any data to be received would have been available.
345 	 */
346 	count = 0;
347 	err = usb_bulk_msg(dev->udev, usb_rcvbulkpipe(dev->udev, dev->ep[EP_DATA_IN]),
348 				buf, size, &count, 1000);
349 	if (err < 0) {
350 		pr_info("Clearing ep0x%x.\n", dev->ep[EP_DATA_IN]);
351 		usb_clear_halt(dev->udev, usb_rcvbulkpipe(dev->udev, dev->ep[EP_DATA_IN]));
352 		ds_recv_status(dev, NULL, true);
353 		return err;
354 	}
355 
356 #if 0
357 	{
358 		int i;
359 
360 		printk("%s: count=%d: ", __func__, count);
361 		for (i=0; i<count; ++i)
362 			printk("%02x ", buf[i]);
363 		printk("\n");
364 	}
365 #endif
366 	return count;
367 }
368 
369 static int ds_send_data(struct ds_device *dev, unsigned char *buf, int len)
370 {
371 	int count, err;
372 
373 	count = 0;
374 	err = usb_bulk_msg(dev->udev, usb_sndbulkpipe(dev->udev, dev->ep[EP_DATA_OUT]), buf, len, &count, 1000);
375 	if (err < 0) {
376 		pr_err("Failed to write 1-wire data to ep0x%x: "
377 			"err=%d.\n", dev->ep[EP_DATA_OUT], err);
378 		return err;
379 	}
380 
381 	return err;
382 }
383 
384 #if 0
385 
386 int ds_stop_pulse(struct ds_device *dev, int limit)
387 {
388 	struct ds_status st;
389 	int count = 0, err = 0;
390 
391 	do {
392 		err = ds_send_control(dev, CTL_HALT_EXE_IDLE, 0);
393 		if (err)
394 			break;
395 		err = ds_send_control(dev, CTL_RESUME_EXE, 0);
396 		if (err)
397 			break;
398 		err = ds_recv_status(dev, &st, false);
399 		if (err)
400 			break;
401 
402 		if ((st.status & ST_SPUA) == 0) {
403 			err = ds_send_control_mode(dev, MOD_PULSE_EN, 0);
404 			if (err)
405 				break;
406 		}
407 	} while(++count < limit);
408 
409 	return err;
410 }
411 
412 int ds_detect(struct ds_device *dev, struct ds_status *st)
413 {
414 	int err;
415 
416 	err = ds_send_control_cmd(dev, CTL_RESET_DEVICE, 0);
417 	if (err)
418 		return err;
419 
420 	err = ds_send_control(dev, COMM_SET_DURATION | COMM_IM, 0);
421 	if (err)
422 		return err;
423 
424 	err = ds_send_control(dev, COMM_SET_DURATION | COMM_IM | COMM_TYPE, 0x40);
425 	if (err)
426 		return err;
427 
428 	err = ds_send_control_mode(dev, MOD_PULSE_EN, PULSE_PROG);
429 	if (err)
430 		return err;
431 
432 	err = ds_dump_status(dev, st);
433 
434 	return err;
435 }
436 
437 #endif  /*  0  */
438 
439 static int ds_wait_status(struct ds_device *dev, struct ds_status *st)
440 {
441 	int err, count = 0;
442 
443 	do {
444 		st->status = 0;
445 		err = ds_recv_status(dev, st, false);
446 #if 0
447 		if (err >= 0) {
448 			int i;
449 			printk("0x%x: count=%d, status: ", dev->ep[EP_STATUS], err);
450 			for (i=0; i<err; ++i)
451 				printk("%02x ", dev->st_buf[i]);
452 			printk("\n");
453 		}
454 #endif
455 	} while (!(st->status & ST_IDLE) && !(err < 0) && ++count < 100);
456 
457 	if (err >= 16 && st->status & ST_EPOF) {
458 		pr_info("Resetting device after ST_EPOF.\n");
459 		ds_reset_device(dev);
460 		/* Always dump the device status. */
461 		count = 101;
462 	}
463 
464 	/* Dump the status for errors or if there is extended return data.
465 	 * The extended status includes new device detection (maybe someone
466 	 * can do something with it).
467 	 */
468 	if (err > 16 || count >= 100 || err < 0)
469 		ds_dump_status(dev, dev->st_buf, err);
470 
471 	/* Extended data isn't an error.  Well, a short is, but the dump
472 	 * would have already told the user that and we can't do anything
473 	 * about it in software anyway.
474 	 */
475 	if (count >= 100 || err < 0)
476 		return -1;
477 	else
478 		return 0;
479 }
480 
481 static int ds_reset(struct ds_device *dev)
482 {
483 	int err;
484 
485 	/* Other potentionally interesting flags for reset.
486 	 *
487 	 * COMM_NTF: Return result register feedback.  This could be used to
488 	 * detect some conditions such as short, alarming presence, or
489 	 * detect if a new device was detected.
490 	 *
491 	 * COMM_SE which allows SPEED_NORMAL, SPEED_FLEXIBLE, SPEED_OVERDRIVE:
492 	 * Select the data transfer rate.
493 	 */
494 	err = ds_send_control(dev, COMM_1_WIRE_RESET | COMM_IM, SPEED_NORMAL);
495 	if (err)
496 		return err;
497 
498 	return 0;
499 }
500 
501 #if 0
502 static int ds_set_speed(struct ds_device *dev, int speed)
503 {
504 	int err;
505 
506 	if (speed != SPEED_NORMAL && speed != SPEED_FLEXIBLE && speed != SPEED_OVERDRIVE)
507 		return -EINVAL;
508 
509 	if (speed != SPEED_OVERDRIVE)
510 		speed = SPEED_FLEXIBLE;
511 
512 	speed &= 0xff;
513 
514 	err = ds_send_control_mode(dev, MOD_1WIRE_SPEED, speed);
515 	if (err)
516 		return err;
517 
518 	return err;
519 }
520 #endif  /*  0  */
521 
522 static int ds_set_pullup(struct ds_device *dev, int delay)
523 {
524 	int err = 0;
525 	u8 del = 1 + (u8)(delay >> 4);
526 	/* Just storing delay would not get the trunication and roundup. */
527 	int ms = del<<4;
528 
529 	/* Enable spu_bit if a delay is set. */
530 	dev->spu_bit = delay ? COMM_SPU : 0;
531 	/* If delay is zero, it has already been disabled, if the time is
532 	 * the same as the hardware was last programmed to, there is also
533 	 * nothing more to do.  Compare with the recalculated value ms
534 	 * rather than del or delay which can have a different value.
535 	 */
536 	if (delay == 0 || ms == dev->spu_sleep)
537 		return err;
538 
539 	err = ds_send_control(dev, COMM_SET_DURATION | COMM_IM, del);
540 	if (err)
541 		return err;
542 
543 	dev->spu_sleep = ms;
544 
545 	return err;
546 }
547 
548 static int ds_touch_bit(struct ds_device *dev, u8 bit, u8 *tbit)
549 {
550 	int err;
551 	struct ds_status st;
552 
553 	err = ds_send_control(dev, COMM_BIT_IO | COMM_IM | (bit ? COMM_D : 0),
554 		0);
555 	if (err)
556 		return err;
557 
558 	ds_wait_status(dev, &st);
559 
560 	err = ds_recv_data(dev, tbit, sizeof(*tbit));
561 	if (err < 0)
562 		return err;
563 
564 	return 0;
565 }
566 
567 #if 0
568 static int ds_write_bit(struct ds_device *dev, u8 bit)
569 {
570 	int err;
571 	struct ds_status st;
572 
573 	/* Set COMM_ICP to write without a readback.  Note, this will
574 	 * produce one time slot, a down followed by an up with COMM_D
575 	 * only determing the timing.
576 	 */
577 	err = ds_send_control(dev, COMM_BIT_IO | COMM_IM | COMM_ICP |
578 		(bit ? COMM_D : 0), 0);
579 	if (err)
580 		return err;
581 
582 	ds_wait_status(dev, &st);
583 
584 	return 0;
585 }
586 #endif
587 
588 static int ds_write_byte(struct ds_device *dev, u8 byte)
589 {
590 	int err;
591 	struct ds_status st;
592 
593 	err = ds_send_control(dev, COMM_BYTE_IO | COMM_IM | dev->spu_bit, byte);
594 	if (err)
595 		return err;
596 
597 	if (dev->spu_bit)
598 		msleep(dev->spu_sleep);
599 
600 	err = ds_wait_status(dev, &st);
601 	if (err)
602 		return err;
603 
604 	err = ds_recv_data(dev, &dev->byte_buf, 1);
605 	if (err < 0)
606 		return err;
607 
608 	return !(byte == dev->byte_buf);
609 }
610 
611 static int ds_read_byte(struct ds_device *dev, u8 *byte)
612 {
613 	int err;
614 	struct ds_status st;
615 
616 	err = ds_send_control(dev, COMM_BYTE_IO | COMM_IM , 0xff);
617 	if (err)
618 		return err;
619 
620 	ds_wait_status(dev, &st);
621 
622 	err = ds_recv_data(dev, byte, sizeof(*byte));
623 	if (err < 0)
624 		return err;
625 
626 	return 0;
627 }
628 
629 static int ds_read_block(struct ds_device *dev, u8 *buf, int len)
630 {
631 	struct ds_status st;
632 	int err;
633 
634 	if (len > 64*1024)
635 		return -E2BIG;
636 
637 	memset(buf, 0xFF, len);
638 
639 	err = ds_send_data(dev, buf, len);
640 	if (err < 0)
641 		return err;
642 
643 	err = ds_send_control(dev, COMM_BLOCK_IO | COMM_IM, len);
644 	if (err)
645 		return err;
646 
647 	ds_wait_status(dev, &st);
648 
649 	memset(buf, 0x00, len);
650 	err = ds_recv_data(dev, buf, len);
651 
652 	return err;
653 }
654 
655 static int ds_write_block(struct ds_device *dev, u8 *buf, int len)
656 {
657 	int err;
658 	struct ds_status st;
659 
660 	err = ds_send_data(dev, buf, len);
661 	if (err < 0)
662 		return err;
663 
664 	err = ds_send_control(dev, COMM_BLOCK_IO | COMM_IM | dev->spu_bit, len);
665 	if (err)
666 		return err;
667 
668 	if (dev->spu_bit)
669 		msleep(dev->spu_sleep);
670 
671 	ds_wait_status(dev, &st);
672 
673 	err = ds_recv_data(dev, buf, len);
674 	if (err < 0)
675 		return err;
676 
677 	return !(err == len);
678 }
679 
680 static void ds9490r_search(void *data, struct w1_master *master,
681 	u8 search_type, w1_slave_found_callback callback)
682 {
683 	/* When starting with an existing id, the first id returned will
684 	 * be that device (if it is still on the bus most likely).
685 	 *
686 	 * If the number of devices found is less than or equal to the
687 	 * search_limit, that number of IDs will be returned.  If there are
688 	 * more, search_limit IDs will be returned followed by a non-zero
689 	 * discrepency value.
690 	 */
691 	struct ds_device *dev = data;
692 	int err;
693 	u16 value, index;
694 	struct ds_status st;
695 	int search_limit;
696 	int found = 0;
697 	int i;
698 
699 	/* DS18b20 spec, 13.16 ms per device, 75 per second, sleep for
700 	 * discovering 8 devices (1 bulk transfer and 1/2 FIFO size) at a time.
701 	 */
702 	const unsigned long jtime = msecs_to_jiffies(1000*8/75);
703 	/* FIFO 128 bytes, bulk packet size 64, read a multiple of the
704 	 * packet size.
705 	 */
706 	const size_t bufsize = 2 * 64;
707 	u64 *buf;
708 
709 	buf = kmalloc(bufsize, GFP_KERNEL);
710 	if (!buf)
711 		return;
712 
713 	mutex_lock(&master->bus_mutex);
714 
715 	/* address to start searching at */
716 	if (ds_send_data(dev, (u8 *)&master->search_id, 8) < 0)
717 		goto search_out;
718 	master->search_id = 0;
719 
720 	value = COMM_SEARCH_ACCESS | COMM_IM | COMM_RST | COMM_SM | COMM_F |
721 		COMM_RTS;
722 	search_limit = master->max_slave_count;
723 	if (search_limit > 255)
724 		search_limit = 0;
725 	index = search_type | (search_limit << 8);
726 	if (ds_send_control(dev, value, index) < 0)
727 		goto search_out;
728 
729 	do {
730 		schedule_timeout(jtime);
731 
732 		err = ds_recv_status(dev, &st, false);
733 		if (err < 0 || err < sizeof(st))
734 			break;
735 
736 		if (st.data_in_buffer_status) {
737 			/* Bulk in can receive partial ids, but when it does
738 			 * they fail crc and will be discarded anyway.
739 			 * That has only been seen when status in buffer
740 			 * is 0 and bulk is read anyway, so don't read
741 			 * bulk without first checking if status says there
742 			 * is data to read.
743 			 */
744 			err = ds_recv_data(dev, (u8 *)buf, bufsize);
745 			if (err < 0)
746 				break;
747 			for (i = 0; i < err/8; ++i) {
748 				++found;
749 				if (found <= search_limit)
750 					callback(master, buf[i]);
751 				/* can't know if there will be a discrepancy
752 				 * value after until the next id */
753 				if (found == search_limit)
754 					master->search_id = buf[i];
755 			}
756 		}
757 
758 		if (test_bit(W1_ABORT_SEARCH, &master->flags))
759 			break;
760 	} while (!(st.status & (ST_IDLE | ST_HALT)));
761 
762 	/* only continue the search if some weren't found */
763 	if (found <= search_limit) {
764 		master->search_id = 0;
765 	} else if (!test_bit(W1_WARN_MAX_COUNT, &master->flags)) {
766 		/* Only max_slave_count will be scanned in a search,
767 		 * but it will start where it left off next search
768 		 * until all ids are identified and then it will start
769 		 * over.  A continued search will report the previous
770 		 * last id as the first id (provided it is still on the
771 		 * bus).
772 		 */
773 		dev_info(&dev->udev->dev, "%s: max_slave_count %d reached, "
774 			"will continue next search.\n", __func__,
775 			master->max_slave_count);
776 		set_bit(W1_WARN_MAX_COUNT, &master->flags);
777 	}
778 search_out:
779 	mutex_unlock(&master->bus_mutex);
780 	kfree(buf);
781 }
782 
783 #if 0
784 /*
785  * FIXME: if this disabled code is ever used in the future all ds_send_data()
786  * calls must be changed to use a DMAable buffer.
787  */
788 static int ds_match_access(struct ds_device *dev, u64 init)
789 {
790 	int err;
791 	struct ds_status st;
792 
793 	err = ds_send_data(dev, (unsigned char *)&init, sizeof(init));
794 	if (err)
795 		return err;
796 
797 	ds_wait_status(dev, &st);
798 
799 	err = ds_send_control(dev, COMM_MATCH_ACCESS | COMM_IM | COMM_RST, 0x0055);
800 	if (err)
801 		return err;
802 
803 	ds_wait_status(dev, &st);
804 
805 	return 0;
806 }
807 
808 static int ds_set_path(struct ds_device *dev, u64 init)
809 {
810 	int err;
811 	struct ds_status st;
812 	u8 buf[9];
813 
814 	memcpy(buf, &init, 8);
815 	buf[8] = BRANCH_MAIN;
816 
817 	err = ds_send_data(dev, buf, sizeof(buf));
818 	if (err)
819 		return err;
820 
821 	ds_wait_status(dev, &st);
822 
823 	err = ds_send_control(dev, COMM_SET_PATH | COMM_IM | COMM_RST, 0);
824 	if (err)
825 		return err;
826 
827 	ds_wait_status(dev, &st);
828 
829 	return 0;
830 }
831 
832 #endif  /*  0  */
833 
834 static u8 ds9490r_touch_bit(void *data, u8 bit)
835 {
836 	struct ds_device *dev = data;
837 
838 	if (ds_touch_bit(dev, bit, &dev->byte_buf))
839 		return 0;
840 
841 	return dev->byte_buf;
842 }
843 
844 #if 0
845 static void ds9490r_write_bit(void *data, u8 bit)
846 {
847 	struct ds_device *dev = data;
848 
849 	ds_write_bit(dev, bit);
850 }
851 
852 static u8 ds9490r_read_bit(void *data)
853 {
854 	struct ds_device *dev = data;
855 	int err;
856 
857 	err = ds_touch_bit(dev, 1, &dev->byte_buf);
858 	if (err)
859 		return 0;
860 
861 	return dev->byte_buf & 1;
862 }
863 #endif
864 
865 static void ds9490r_write_byte(void *data, u8 byte)
866 {
867 	struct ds_device *dev = data;
868 
869 	ds_write_byte(dev, byte);
870 }
871 
872 static u8 ds9490r_read_byte(void *data)
873 {
874 	struct ds_device *dev = data;
875 	int err;
876 
877 	err = ds_read_byte(dev, &dev->byte_buf);
878 	if (err)
879 		return 0;
880 
881 	return dev->byte_buf;
882 }
883 
884 static void ds9490r_write_block(void *data, const u8 *buf, int len)
885 {
886 	struct ds_device *dev = data;
887 	u8 *tbuf;
888 
889 	if (len <= 0)
890 		return;
891 
892 	tbuf = kmemdup(buf, len, GFP_KERNEL);
893 	if (!tbuf)
894 		return;
895 
896 	ds_write_block(dev, tbuf, len);
897 
898 	kfree(tbuf);
899 }
900 
901 static u8 ds9490r_read_block(void *data, u8 *buf, int len)
902 {
903 	struct ds_device *dev = data;
904 	int err;
905 	u8 *tbuf;
906 
907 	if (len <= 0)
908 		return 0;
909 
910 	tbuf = kmalloc(len, GFP_KERNEL);
911 	if (!tbuf)
912 		return 0;
913 
914 	err = ds_read_block(dev, tbuf, len);
915 	if (err >= 0)
916 		memcpy(buf, tbuf, len);
917 
918 	kfree(tbuf);
919 
920 	return err >= 0 ? len : 0;
921 }
922 
923 static u8 ds9490r_reset(void *data)
924 {
925 	struct ds_device *dev = data;
926 	int err;
927 
928 	err = ds_reset(dev);
929 	if (err)
930 		return 1;
931 
932 	return 0;
933 }
934 
935 static u8 ds9490r_set_pullup(void *data, int delay)
936 {
937 	struct ds_device *dev = data;
938 
939 	if (ds_set_pullup(dev, delay))
940 		return 1;
941 
942 	return 0;
943 }
944 
945 static int ds_w1_init(struct ds_device *dev)
946 {
947 	memset(&dev->master, 0, sizeof(struct w1_bus_master));
948 
949 	/* Reset the device as it can be in a bad state.
950 	 * This is necessary because a block write will wait for data
951 	 * to be placed in the output buffer and block any later
952 	 * commands which will keep accumulating and the device will
953 	 * not be idle.  Another case is removing the ds2490 module
954 	 * while a bus search is in progress, somehow a few commands
955 	 * get through, but the input transfers fail leaving data in
956 	 * the input buffer.  This will cause the next read to fail
957 	 * see the note in ds_recv_data.
958 	 */
959 	ds_reset_device(dev);
960 
961 	dev->master.data	= dev;
962 	dev->master.touch_bit	= &ds9490r_touch_bit;
963 	/* read_bit and write_bit in w1_bus_master are expected to set and
964 	 * sample the line level.  For write_bit that means it is expected to
965 	 * set it to that value and leave it there.  ds2490 only supports an
966 	 * individual time slot at the lowest level.  The requirement from
967 	 * pulling the bus state down to reading the state is 15us, something
968 	 * that isn't realistic on the USB bus anyway.
969 	dev->master.read_bit	= &ds9490r_read_bit;
970 	dev->master.write_bit	= &ds9490r_write_bit;
971 	*/
972 	dev->master.read_byte	= &ds9490r_read_byte;
973 	dev->master.write_byte	= &ds9490r_write_byte;
974 	dev->master.read_block	= &ds9490r_read_block;
975 	dev->master.write_block	= &ds9490r_write_block;
976 	dev->master.reset_bus	= &ds9490r_reset;
977 	dev->master.set_pullup	= &ds9490r_set_pullup;
978 	dev->master.search	= &ds9490r_search;
979 
980 	return w1_add_master_device(&dev->master);
981 }
982 
983 static void ds_w1_fini(struct ds_device *dev)
984 {
985 	w1_remove_master_device(&dev->master);
986 }
987 
988 static int ds_probe(struct usb_interface *intf,
989 		    const struct usb_device_id *udev_id)
990 {
991 	struct usb_device *udev = interface_to_usbdev(intf);
992 	struct usb_endpoint_descriptor *endpoint;
993 	struct usb_host_interface *iface_desc;
994 	struct ds_device *dev;
995 	int i, err, alt;
996 
997 	dev = kzalloc(sizeof(struct ds_device), GFP_KERNEL);
998 	if (!dev) {
999 		pr_info("Failed to allocate new DS9490R structure.\n");
1000 		return -ENOMEM;
1001 	}
1002 	dev->udev = usb_get_dev(udev);
1003 	if (!dev->udev) {
1004 		err = -ENOMEM;
1005 		goto err_out_free;
1006 	}
1007 	memset(dev->ep, 0, sizeof(dev->ep));
1008 
1009 	usb_set_intfdata(intf, dev);
1010 
1011 	err = usb_reset_configuration(dev->udev);
1012 	if (err) {
1013 		dev_err(&dev->udev->dev,
1014 			"Failed to reset configuration: err=%d.\n", err);
1015 		goto err_out_clear;
1016 	}
1017 
1018 	/* alternative 3, 1ms interrupt (greatly speeds search), 64 byte bulk */
1019 	alt = 3;
1020 	err = usb_set_interface(dev->udev,
1021 		intf->altsetting[alt].desc.bInterfaceNumber, alt);
1022 	if (err) {
1023 		dev_err(&dev->udev->dev, "Failed to set alternative setting %d "
1024 			"for %d interface: err=%d.\n", alt,
1025 			intf->altsetting[alt].desc.bInterfaceNumber, err);
1026 		goto err_out_clear;
1027 	}
1028 
1029 	iface_desc = &intf->altsetting[alt];
1030 	if (iface_desc->desc.bNumEndpoints != NUM_EP-1) {
1031 		pr_info("Num endpoints=%d. It is not DS9490R.\n",
1032 			iface_desc->desc.bNumEndpoints);
1033 		err = -EINVAL;
1034 		goto err_out_clear;
1035 	}
1036 
1037 	/*
1038 	 * This loop doesn'd show control 0 endpoint,
1039 	 * so we will fill only 1-3 endpoints entry.
1040 	 */
1041 	for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
1042 		endpoint = &iface_desc->endpoint[i].desc;
1043 
1044 		dev->ep[i+1] = endpoint->bEndpointAddress;
1045 #if 0
1046 		printk("%d: addr=%x, size=%d, dir=%s, type=%x\n",
1047 			i, endpoint->bEndpointAddress, le16_to_cpu(endpoint->wMaxPacketSize),
1048 			(endpoint->bEndpointAddress & USB_DIR_IN)?"IN":"OUT",
1049 			endpoint->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK);
1050 #endif
1051 	}
1052 
1053 	err = ds_w1_init(dev);
1054 	if (err)
1055 		goto err_out_clear;
1056 
1057 	mutex_lock(&ds_mutex);
1058 	list_add_tail(&dev->ds_entry, &ds_devices);
1059 	mutex_unlock(&ds_mutex);
1060 
1061 	return 0;
1062 
1063 err_out_clear:
1064 	usb_set_intfdata(intf, NULL);
1065 	usb_put_dev(dev->udev);
1066 err_out_free:
1067 	kfree(dev);
1068 	return err;
1069 }
1070 
1071 static void ds_disconnect(struct usb_interface *intf)
1072 {
1073 	struct ds_device *dev;
1074 
1075 	dev = usb_get_intfdata(intf);
1076 	if (!dev)
1077 		return;
1078 
1079 	mutex_lock(&ds_mutex);
1080 	list_del(&dev->ds_entry);
1081 	mutex_unlock(&ds_mutex);
1082 
1083 	ds_w1_fini(dev);
1084 
1085 	usb_set_intfdata(intf, NULL);
1086 
1087 	usb_put_dev(dev->udev);
1088 	kfree(dev);
1089 }
1090 
1091 static const struct usb_device_id ds_id_table[] = {
1092 	{ USB_DEVICE(0x04fa, 0x2490) },
1093 	{ },
1094 };
1095 MODULE_DEVICE_TABLE(usb, ds_id_table);
1096 
1097 static struct usb_driver ds_driver = {
1098 	.name =		"DS9490R",
1099 	.probe =	ds_probe,
1100 	.disconnect =	ds_disconnect,
1101 	.id_table =	ds_id_table,
1102 };
1103 module_usb_driver(ds_driver);
1104 
1105 MODULE_AUTHOR("Evgeniy Polyakov <zbr@ioremap.net>");
1106 MODULE_DESCRIPTION("DS2490 USB <-> W1 bus master driver (DS9490*)");
1107 MODULE_LICENSE("GPL");
1108