xref: /linux/drivers/w1/masters/ds2490.c (revision 2697b79a469b68e3ad3640f55284359c1396278d)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *	ds2490.c  USB to one wire bridge
4  *
5  * Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
6  */
7 
8 #include <linux/module.h>
9 #include <linux/kernel.h>
10 #include <linux/mod_devicetable.h>
11 #include <linux/usb.h>
12 #include <linux/slab.h>
13 
14 #include <linux/w1.h>
15 
16 /* USB Standard */
17 /* USB Control request vendor type */
18 #define VENDOR				0x40
19 
20 /* COMMAND TYPE CODES */
21 #define CONTROL_CMD			0x00
22 #define COMM_CMD			0x01
23 #define MODE_CMD			0x02
24 
25 /* CONTROL COMMAND CODES */
26 #define CTL_RESET_DEVICE		0x0000
27 #define CTL_START_EXE			0x0001
28 #define CTL_RESUME_EXE			0x0002
29 #define CTL_HALT_EXE_IDLE		0x0003
30 #define CTL_HALT_EXE_DONE		0x0004
31 #define CTL_FLUSH_COMM_CMDS		0x0007
32 #define CTL_FLUSH_RCV_BUFFER		0x0008
33 #define CTL_FLUSH_XMT_BUFFER		0x0009
34 #define CTL_GET_COMM_CMDS		0x000A
35 
36 /* MODE COMMAND CODES */
37 #define MOD_PULSE_EN			0x0000
38 #define MOD_SPEED_CHANGE_EN		0x0001
39 #define MOD_1WIRE_SPEED			0x0002
40 #define MOD_STRONG_PU_DURATION		0x0003
41 #define MOD_PULLDOWN_SLEWRATE		0x0004
42 #define MOD_PROG_PULSE_DURATION		0x0005
43 #define MOD_WRITE1_LOWTIME		0x0006
44 #define MOD_DSOW0_TREC			0x0007
45 
46 /* COMMUNICATION COMMAND CODES */
47 #define COMM_ERROR_ESCAPE		0x0601
48 #define COMM_SET_DURATION		0x0012
49 #define COMM_BIT_IO			0x0020
50 #define COMM_PULSE			0x0030
51 #define COMM_1_WIRE_RESET		0x0042
52 #define COMM_BYTE_IO			0x0052
53 #define COMM_MATCH_ACCESS		0x0064
54 #define COMM_BLOCK_IO			0x0074
55 #define COMM_READ_STRAIGHT		0x0080
56 #define COMM_DO_RELEASE			0x6092
57 #define COMM_SET_PATH			0x00A2
58 #define COMM_WRITE_SRAM_PAGE		0x00B2
59 #define COMM_WRITE_EPROM		0x00C4
60 #define COMM_READ_CRC_PROT_PAGE		0x00D4
61 #define COMM_READ_REDIRECT_PAGE_CRC	0x21E4
62 #define COMM_SEARCH_ACCESS		0x00F4
63 
64 /* Communication command bits */
65 #define COMM_TYPE			0x0008
66 #define COMM_SE				0x0008
67 #define COMM_D				0x0008
68 #define COMM_Z				0x0008
69 #define COMM_CH				0x0008
70 #define COMM_SM				0x0008
71 #define COMM_R				0x0008
72 #define COMM_IM				0x0001
73 
74 #define COMM_PS				0x4000
75 #define COMM_PST			0x4000
76 #define COMM_CIB			0x4000
77 #define COMM_RTS			0x4000
78 #define COMM_DT				0x2000
79 #define COMM_SPU			0x1000
80 #define COMM_F				0x0800
81 #define COMM_NTF			0x0400
82 #define COMM_ICP			0x0200
83 #define COMM_RST			0x0100
84 
85 #define PULSE_PROG			0x01
86 #define PULSE_SPUE			0x02
87 
88 #define BRANCH_MAIN			0xCC
89 #define BRANCH_AUX			0x33
90 
91 /* Status flags */
92 #define ST_SPUA				0x01  /* Strong Pull-up is active */
93 #define ST_PRGA				0x02  /* 12V programming pulse is being generated */
94 #define ST_12VP				0x04  /* external 12V programming voltage is present */
95 #define ST_PMOD				0x08  /* DS2490 powered from USB and external sources */
96 #define ST_HALT				0x10  /* DS2490 is currently halted */
97 #define ST_IDLE				0x20  /* DS2490 is currently idle */
98 #define ST_EPOF				0x80
99 /* Status transfer size, 16 bytes status, 16 byte result flags */
100 #define ST_SIZE				0x20
101 /* 1-wire data i/o fifo size, 128 bytes */
102 #define FIFO_SIZE			0x80
103 
104 /* Result Register flags */
105 #define RR_DETECT			0xA5 /* New device detected */
106 #define RR_NRS				0x01 /* Reset no presence or ... */
107 #define RR_SH				0x02 /* short on reset or set path */
108 #define RR_APP				0x04 /* alarming presence on reset */
109 #define RR_VPP				0x08 /* 12V expected not seen */
110 #define RR_CMP				0x10 /* compare error */
111 #define RR_CRC				0x20 /* CRC error detected */
112 #define RR_RDP				0x40 /* redirected page */
113 #define RR_EOS				0x80 /* end of search error */
114 
115 #define SPEED_NORMAL			0x00
116 #define SPEED_FLEXIBLE			0x01
117 #define SPEED_OVERDRIVE			0x02
118 
119 #define NUM_EP				4
120 #define EP_CONTROL			0
121 #define EP_STATUS			1
122 #define EP_DATA_OUT			2
123 #define EP_DATA_IN			3
124 
125 struct ds_device {
126 	struct list_head	ds_entry;
127 
128 	struct usb_device	*udev;
129 	struct usb_interface	*intf;
130 
131 	int			ep[NUM_EP];
132 
133 	/* Strong PullUp
134 	 * 0: pullup not active, else duration in milliseconds
135 	 */
136 	int			spu_sleep;
137 	/* spu_bit contains COMM_SPU or 0 depending on if the strong pullup
138 	 * should be active or not for writes.
139 	 */
140 	u16			spu_bit;
141 
142 	u8			st_buf[ST_SIZE];
143 	u8			byte_buf;
144 
145 	struct w1_bus_master	master;
146 };
147 
148 struct ds_status {
149 	u8			enable;
150 	u8			speed;
151 	u8			pullup_dur;
152 	u8			ppuls_dur;
153 	u8			pulldown_slew;
154 	u8			write1_time;
155 	u8			write0_time;
156 	u8			reserved0;
157 	u8			status;
158 	u8			command0;
159 	u8			command1;
160 	u8			command_buffer_status;
161 	u8			data_out_buffer_status;
162 	u8			data_in_buffer_status;
163 	u8			reserved1;
164 	u8			reserved2;
165 };
166 
167 static LIST_HEAD(ds_devices);
168 static DEFINE_MUTEX(ds_mutex);
169 
170 static int ds_send_control_cmd(struct ds_device *dev, u16 value, u16 index)
171 {
172 	int err;
173 
174 	err = usb_control_msg(dev->udev, usb_sndctrlpipe(dev->udev, dev->ep[EP_CONTROL]),
175 			CONTROL_CMD, VENDOR, value, index, NULL, 0, 1000);
176 	if (err < 0) {
177 		dev_err(&dev->udev->dev,
178 			"Failed to send command control message %x.%x: err=%d.\n",
179 			value, index, err);
180 		return err;
181 	}
182 
183 	return err;
184 }
185 
186 static int ds_send_control_mode(struct ds_device *dev, u16 value, u16 index)
187 {
188 	int err;
189 
190 	err = usb_control_msg(dev->udev, usb_sndctrlpipe(dev->udev, dev->ep[EP_CONTROL]),
191 			MODE_CMD, VENDOR, value, index, NULL, 0, 1000);
192 	if (err < 0) {
193 		dev_err(&dev->udev->dev,
194 			"Failed to send mode control message %x.%x: err=%d.\n",
195 			value, index, err);
196 		return err;
197 	}
198 
199 	return err;
200 }
201 
202 static int ds_send_control(struct ds_device *dev, u16 value, u16 index)
203 {
204 	int err;
205 
206 	err = usb_control_msg(dev->udev, usb_sndctrlpipe(dev->udev, dev->ep[EP_CONTROL]),
207 			COMM_CMD, VENDOR, value, index, NULL, 0, 1000);
208 	if (err < 0) {
209 		dev_err(&dev->udev->dev,
210 			"Failed to send control message %x.%x: err=%d.\n",
211 			value, index, err);
212 		return err;
213 	}
214 
215 	return err;
216 }
217 
218 static void ds_dump_status(struct ds_device *ds_dev, unsigned char *buf, int count)
219 {
220 	struct device *dev = &ds_dev->udev->dev;
221 	int i;
222 
223 	dev_info(dev, "ep_status=0x%x, count=%d, status=%*phC",
224 		ds_dev->ep[EP_STATUS], count, count, buf);
225 
226 	if (count >= 16) {
227 		dev_dbg(dev, "enable flag: 0x%02x", buf[0]);
228 		dev_dbg(dev, "1-wire speed: 0x%02x", buf[1]);
229 		dev_dbg(dev, "strong pullup duration: 0x%02x", buf[2]);
230 		dev_dbg(dev, "programming pulse duration: 0x%02x", buf[3]);
231 		dev_dbg(dev, "pulldown slew rate control: 0x%02x", buf[4]);
232 		dev_dbg(dev, "write-1 low time: 0x%02x", buf[5]);
233 		dev_dbg(dev, "data sample offset/write-0 recovery time: 0x%02x", buf[6]);
234 		dev_dbg(dev, "reserved (test register): 0x%02x", buf[7]);
235 		dev_dbg(dev, "device status flags: 0x%02x", buf[8]);
236 		dev_dbg(dev, "communication command byte 1: 0x%02x", buf[9]);
237 		dev_dbg(dev, "communication command byte 2: 0x%02x", buf[10]);
238 		dev_dbg(dev, "communication command buffer status: 0x%02x", buf[11]);
239 		dev_dbg(dev, "1-wire data output buffer status: 0x%02x", buf[12]);
240 		dev_dbg(dev, "1-wire data input buffer status: 0x%02x", buf[13]);
241 		dev_dbg(dev, "reserved: 0x%02x", buf[14]);
242 		dev_dbg(dev, "reserved: 0x%02x", buf[15]);
243 	}
244 
245 	for (i = 16; i < count; ++i) {
246 		if (buf[i] == RR_DETECT) {
247 			dev_dbg(dev, "New device detect.\n");
248 			continue;
249 		}
250 		dev_dbg(dev, "Result Register Value: 0x%02x", buf[i]);
251 		if (buf[i] & RR_NRS)
252 			dev_dbg(dev, "NRS: Reset no presence or ...\n");
253 		if (buf[i] & RR_SH)
254 			dev_dbg(dev, "SH: short on reset or set path\n");
255 		if (buf[i] & RR_APP)
256 			dev_dbg(dev, "APP: alarming presence on reset\n");
257 		if (buf[i] & RR_VPP)
258 			dev_dbg(dev, "VPP: 12V expected not seen\n");
259 		if (buf[i] & RR_CMP)
260 			dev_dbg(dev, "CMP: compare error\n");
261 		if (buf[i] & RR_CRC)
262 			dev_dbg(dev, "CRC: CRC error detected\n");
263 		if (buf[i] & RR_RDP)
264 			dev_dbg(dev, "RDP: redirected page\n");
265 		if (buf[i] & RR_EOS)
266 			dev_dbg(dev, "EOS: end of search error\n");
267 	}
268 }
269 
270 static int ds_recv_status(struct ds_device *dev, struct ds_status *st)
271 {
272 	int count, err;
273 
274 	if (st)
275 		memset(st, 0, sizeof(*st));
276 
277 	count = 0;
278 	err = usb_interrupt_msg(dev->udev,
279 				usb_rcvintpipe(dev->udev,
280 					       dev->ep[EP_STATUS]),
281 				dev->st_buf, sizeof(dev->st_buf),
282 				&count, 1000);
283 	if (err < 0) {
284 		dev_err(&dev->udev->dev,
285 			"Failed to read 1-wire data from 0x%x: err=%d.\n",
286 			dev->ep[EP_STATUS], err);
287 		return err;
288 	}
289 
290 	if (st && count >= sizeof(*st))
291 		memcpy(st, dev->st_buf, sizeof(*st));
292 
293 	return count;
294 }
295 
296 static void ds_reset_device(struct ds_device *dev)
297 {
298 	ds_send_control_cmd(dev, CTL_RESET_DEVICE, 0);
299 	/* Always allow strong pullup which allow individual writes to use
300 	 * the strong pullup.
301 	 */
302 	if (ds_send_control_mode(dev, MOD_PULSE_EN, PULSE_SPUE))
303 		dev_err(&dev->udev->dev,
304 			"%s: Error allowing strong pullup\n", __func__);
305 	/* Chip strong pullup time was cleared. */
306 	if (dev->spu_sleep) {
307 		/* lower 4 bits are 0, see ds_set_pullup */
308 		u8 del = dev->spu_sleep>>4;
309 
310 		if (ds_send_control(dev, COMM_SET_DURATION | COMM_IM, del))
311 			dev_err(&dev->udev->dev,
312 				"%s: Error setting duration\n", __func__);
313 	}
314 }
315 
316 static int ds_recv_data(struct ds_device *dev, unsigned char *buf, int size)
317 {
318 	int count, err;
319 
320 	/* Careful on size.  If size is less than what is available in
321 	 * the input buffer, the device fails the bulk transfer and
322 	 * clears the input buffer.  It could read the maximum size of
323 	 * the data buffer, but then do you return the first, last, or
324 	 * some set of the middle size bytes?  As long as the rest of
325 	 * the code is correct there will be size bytes waiting.  A
326 	 * call to ds_wait_status will wait until the device is idle
327 	 * and any data to be received would have been available.
328 	 */
329 	count = 0;
330 	err = usb_bulk_msg(dev->udev, usb_rcvbulkpipe(dev->udev, dev->ep[EP_DATA_IN]),
331 				buf, size, &count, 1000);
332 	if (err < 0) {
333 		int recv_len;
334 
335 		dev_info(&dev->udev->dev, "Clearing ep0x%x.\n", dev->ep[EP_DATA_IN]);
336 		usb_clear_halt(dev->udev, usb_rcvbulkpipe(dev->udev, dev->ep[EP_DATA_IN]));
337 
338 		/* status might tell us why endpoint is stuck? */
339 		recv_len = ds_recv_status(dev, NULL);
340 		if (recv_len >= 0)
341 			ds_dump_status(dev, dev->st_buf, recv_len);
342 
343 		return err;
344 	}
345 
346 #if 0
347 	{
348 		int i;
349 
350 		printk("%s: count=%d: ", __func__, count);
351 		for (i = 0; i < count; ++i)
352 			printk("%02x ", buf[i]);
353 		printk("\n");
354 	}
355 #endif
356 	return count;
357 }
358 
359 static int ds_send_data(struct ds_device *dev, unsigned char *buf, int len)
360 {
361 	int count, err;
362 
363 	count = 0;
364 	err = usb_bulk_msg(dev->udev, usb_sndbulkpipe(dev->udev, dev->ep[EP_DATA_OUT]), buf, len, &count, 1000);
365 	if (err < 0) {
366 		dev_err(&dev->udev->dev, "Failed to write 1-wire data to ep0x%x: "
367 			"err=%d.\n", dev->ep[EP_DATA_OUT], err);
368 		return err;
369 	}
370 
371 	return err;
372 }
373 
374 #if 0
375 
376 int ds_stop_pulse(struct ds_device *dev, int limit)
377 {
378 	struct ds_status st;
379 	int count = 0, err = 0;
380 
381 	do {
382 		err = ds_send_control(dev, CTL_HALT_EXE_IDLE, 0);
383 		if (err)
384 			break;
385 		err = ds_send_control(dev, CTL_RESUME_EXE, 0);
386 		if (err)
387 			break;
388 		err = ds_recv_status(dev, &st);
389 		if (err)
390 			break;
391 
392 		if ((st.status & ST_SPUA) == 0) {
393 			err = ds_send_control_mode(dev, MOD_PULSE_EN, 0);
394 			if (err)
395 				break;
396 		}
397 	} while (++count < limit);
398 
399 	return err;
400 }
401 
402 int ds_detect(struct ds_device *dev, struct ds_status *st)
403 {
404 	int err;
405 
406 	err = ds_send_control_cmd(dev, CTL_RESET_DEVICE, 0);
407 	if (err)
408 		return err;
409 
410 	err = ds_send_control(dev, COMM_SET_DURATION | COMM_IM, 0);
411 	if (err)
412 		return err;
413 
414 	err = ds_send_control(dev, COMM_SET_DURATION | COMM_IM | COMM_TYPE, 0x40);
415 	if (err)
416 		return err;
417 
418 	err = ds_send_control_mode(dev, MOD_PULSE_EN, PULSE_PROG);
419 	if (err)
420 		return err;
421 
422 	err = ds_dump_status(dev, st);
423 
424 	return err;
425 }
426 
427 #endif  /*  0  */
428 
429 static int ds_wait_status(struct ds_device *dev, struct ds_status *st)
430 {
431 	int err, count = 0;
432 
433 	do {
434 		st->status = 0;
435 		err = ds_recv_status(dev, st);
436 #if 0
437 		if (err >= 0) {
438 			int i;
439 			printk("0x%x: count=%d, status: ", dev->ep[EP_STATUS], err);
440 			for (i = 0; i < err; ++i)
441 				printk("%02x ", dev->st_buf[i]);
442 			printk("\n");
443 		}
444 #endif
445 	} while (!(st->status & ST_IDLE) && !(err < 0) && ++count < 100);
446 
447 	if (err >= 16 && st->status & ST_EPOF) {
448 		dev_info(&dev->udev->dev, "Resetting device after ST_EPOF.\n");
449 		ds_reset_device(dev);
450 		/* Always dump the device status. */
451 		count = 101;
452 	}
453 
454 	/* Dump the status for errors or if there is extended return data.
455 	 * The extended status includes new device detection (maybe someone
456 	 * can do something with it).
457 	 */
458 	if (err > 16 || count >= 100 || err < 0)
459 		ds_dump_status(dev, dev->st_buf, err);
460 
461 	/* Extended data isn't an error.  Well, a short is, but the dump
462 	 * would have already told the user that and we can't do anything
463 	 * about it in software anyway.
464 	 */
465 	if (count >= 100 || err < 0)
466 		return -1;
467 	else
468 		return 0;
469 }
470 
471 static int ds_reset(struct ds_device *dev)
472 {
473 	int err;
474 
475 	/* Other potentionally interesting flags for reset.
476 	 *
477 	 * COMM_NTF: Return result register feedback.  This could be used to
478 	 * detect some conditions such as short, alarming presence, or
479 	 * detect if a new device was detected.
480 	 *
481 	 * COMM_SE which allows SPEED_NORMAL, SPEED_FLEXIBLE, SPEED_OVERDRIVE:
482 	 * Select the data transfer rate.
483 	 */
484 	err = ds_send_control(dev, COMM_1_WIRE_RESET | COMM_IM, SPEED_NORMAL);
485 	if (err)
486 		return err;
487 
488 	return 0;
489 }
490 
491 #if 0
492 static int ds_set_speed(struct ds_device *dev, int speed)
493 {
494 	int err;
495 
496 	if (speed != SPEED_NORMAL && speed != SPEED_FLEXIBLE && speed != SPEED_OVERDRIVE)
497 		return -EINVAL;
498 
499 	if (speed != SPEED_OVERDRIVE)
500 		speed = SPEED_FLEXIBLE;
501 
502 	speed &= 0xff;
503 
504 	err = ds_send_control_mode(dev, MOD_1WIRE_SPEED, speed);
505 	if (err)
506 		return err;
507 
508 	return err;
509 }
510 #endif  /*  0  */
511 
512 static int ds_set_pullup(struct ds_device *dev, int delay)
513 {
514 	int err = 0;
515 	u8 del = 1 + (u8)(delay >> 4);
516 	/* Just storing delay would not get the trunication and roundup. */
517 	int ms = del<<4;
518 
519 	/* Enable spu_bit if a delay is set. */
520 	dev->spu_bit = delay ? COMM_SPU : 0;
521 	/* If delay is zero, it has already been disabled, if the time is
522 	 * the same as the hardware was last programmed to, there is also
523 	 * nothing more to do.  Compare with the recalculated value ms
524 	 * rather than del or delay which can have a different value.
525 	 */
526 	if (delay == 0 || ms == dev->spu_sleep)
527 		return err;
528 
529 	err = ds_send_control(dev, COMM_SET_DURATION | COMM_IM, del);
530 	if (err)
531 		return err;
532 
533 	dev->spu_sleep = ms;
534 
535 	return err;
536 }
537 
538 static int ds_touch_bit(struct ds_device *dev, u8 bit, u8 *tbit)
539 {
540 	int err;
541 	struct ds_status st;
542 
543 	err = ds_send_control(dev, COMM_BIT_IO | COMM_IM | (bit ? COMM_D : 0),
544 		0);
545 	if (err)
546 		return err;
547 
548 	ds_wait_status(dev, &st);
549 
550 	err = ds_recv_data(dev, tbit, sizeof(*tbit));
551 	if (err < 0)
552 		return err;
553 
554 	return 0;
555 }
556 
557 #if 0
558 static int ds_write_bit(struct ds_device *dev, u8 bit)
559 {
560 	int err;
561 	struct ds_status st;
562 
563 	/* Set COMM_ICP to write without a readback.  Note, this will
564 	 * produce one time slot, a down followed by an up with COMM_D
565 	 * only determing the timing.
566 	 */
567 	err = ds_send_control(dev, COMM_BIT_IO | COMM_IM | COMM_ICP |
568 		(bit ? COMM_D : 0), 0);
569 	if (err)
570 		return err;
571 
572 	ds_wait_status(dev, &st);
573 
574 	return 0;
575 }
576 #endif
577 
578 static int ds_write_byte(struct ds_device *dev, u8 byte)
579 {
580 	int err;
581 	struct ds_status st;
582 
583 	err = ds_send_control(dev, COMM_BYTE_IO | COMM_IM | dev->spu_bit, byte);
584 	if (err)
585 		return err;
586 
587 	if (dev->spu_bit)
588 		msleep(dev->spu_sleep);
589 
590 	err = ds_wait_status(dev, &st);
591 	if (err)
592 		return err;
593 
594 	err = ds_recv_data(dev, &dev->byte_buf, 1);
595 	if (err < 0)
596 		return err;
597 
598 	return !(byte == dev->byte_buf);
599 }
600 
601 static int ds_read_byte(struct ds_device *dev, u8 *byte)
602 {
603 	int err;
604 	struct ds_status st;
605 
606 	err = ds_send_control(dev, COMM_BYTE_IO | COMM_IM, 0xff);
607 	if (err)
608 		return err;
609 
610 	ds_wait_status(dev, &st);
611 
612 	err = ds_recv_data(dev, byte, sizeof(*byte));
613 	if (err < 0)
614 		return err;
615 
616 	return 0;
617 }
618 
619 static int read_block_chunk(struct ds_device *dev, u8 *buf, int len)
620 {
621 	struct ds_status st;
622 	int err;
623 
624 	memset(buf, 0xFF, len);
625 
626 	err = ds_send_data(dev, buf, len);
627 	if (err < 0)
628 		return err;
629 
630 	err = ds_send_control(dev, COMM_BLOCK_IO | COMM_IM, len);
631 	if (err)
632 		return err;
633 
634 	ds_wait_status(dev, &st);
635 
636 	memset(buf, 0x00, len);
637 	err = ds_recv_data(dev, buf, len);
638 
639 	return err;
640 }
641 
642 static int ds_read_block(struct ds_device *dev, u8 *buf, int len)
643 {
644 	int err, to_read, rem = len;
645 
646 	if (len > 64 * 1024)
647 		return -E2BIG;
648 
649 	do {
650 		to_read = rem <= FIFO_SIZE ? rem : FIFO_SIZE;
651 		err = read_block_chunk(dev, &buf[len - rem], to_read);
652 		if (err < 0)
653 			return err;
654 		rem -= to_read;
655 	} while (rem);
656 
657 	return err;
658 }
659 
660 static int ds_write_block(struct ds_device *dev, u8 *buf, int len)
661 {
662 	int err;
663 	struct ds_status st;
664 
665 	err = ds_send_data(dev, buf, len);
666 	if (err < 0)
667 		return err;
668 
669 	err = ds_send_control(dev, COMM_BLOCK_IO | COMM_IM | dev->spu_bit, len);
670 	if (err)
671 		return err;
672 
673 	if (dev->spu_bit)
674 		msleep(dev->spu_sleep);
675 
676 	ds_wait_status(dev, &st);
677 
678 	err = ds_recv_data(dev, buf, len);
679 	if (err < 0)
680 		return err;
681 
682 	return !(err == len);
683 }
684 
685 static void ds9490r_search(void *data, struct w1_master *master,
686 	u8 search_type, w1_slave_found_callback callback)
687 {
688 	/* When starting with an existing id, the first id returned will
689 	 * be that device (if it is still on the bus most likely).
690 	 *
691 	 * If the number of devices found is less than or equal to the
692 	 * search_limit, that number of IDs will be returned.  If there are
693 	 * more, search_limit IDs will be returned followed by a non-zero
694 	 * discrepency value.
695 	 */
696 	struct ds_device *dev = data;
697 	int err;
698 	u16 value, index;
699 	struct ds_status st;
700 	int search_limit;
701 	int found = 0;
702 	int i;
703 
704 	/* DS18b20 spec, 13.16 ms per device, 75 per second, sleep for
705 	 * discovering 8 devices (1 bulk transfer and 1/2 FIFO size) at a time.
706 	 */
707 	const unsigned long jtime = msecs_to_jiffies(1000*8/75);
708 	/* FIFO 128 bytes, bulk packet size 64, read a multiple of the
709 	 * packet size.
710 	 */
711 	const size_t bufsize = 2 * 64;
712 	u64 *buf, *found_ids;
713 
714 	buf = kmalloc(bufsize, GFP_KERNEL);
715 	if (!buf)
716 		return;
717 
718 	/*
719 	 * We are holding the bus mutex during the scan, but adding devices via the
720 	 * callback needs the bus to be unlocked. So we queue up found ids here.
721 	 */
722 	found_ids = kmalloc_array(master->max_slave_count, sizeof(u64), GFP_KERNEL);
723 	if (!found_ids) {
724 		kfree(buf);
725 		return;
726 	}
727 
728 	mutex_lock(&master->bus_mutex);
729 
730 	/* address to start searching at */
731 	if (ds_send_data(dev, (u8 *)&master->search_id, 8) < 0)
732 		goto search_out;
733 	master->search_id = 0;
734 
735 	value = COMM_SEARCH_ACCESS | COMM_IM | COMM_RST | COMM_SM | COMM_F |
736 		COMM_RTS;
737 	search_limit = master->max_slave_count;
738 	if (search_limit > 255)
739 		search_limit = 0;
740 	index = search_type | (search_limit << 8);
741 	if (ds_send_control(dev, value, index) < 0)
742 		goto search_out;
743 
744 	do {
745 		schedule_timeout(jtime);
746 
747 		err = ds_recv_status(dev, &st);
748 		if (err < 0 || err < sizeof(st))
749 			break;
750 
751 		if (st.data_in_buffer_status) {
752 			/*
753 			 * Bulk in can receive partial ids, but when it does
754 			 * they fail crc and will be discarded anyway.
755 			 * That has only been seen when status in buffer
756 			 * is 0 and bulk is read anyway, so don't read
757 			 * bulk without first checking if status says there
758 			 * is data to read.
759 			 */
760 			err = ds_recv_data(dev, (u8 *)buf, bufsize);
761 			if (err < 0)
762 				break;
763 			for (i = 0; i < err/8; ++i) {
764 				found_ids[found++] = buf[i];
765 				/*
766 				 * can't know if there will be a discrepancy
767 				 * value after until the next id
768 				 */
769 				if (found == search_limit) {
770 					master->search_id = buf[i];
771 					break;
772 				}
773 			}
774 		}
775 
776 		if (test_bit(W1_ABORT_SEARCH, &master->flags))
777 			break;
778 	} while (!(st.status & (ST_IDLE | ST_HALT)));
779 
780 	/* only continue the search if some weren't found */
781 	if (found <= search_limit) {
782 		master->search_id = 0;
783 	} else if (!test_bit(W1_WARN_MAX_COUNT, &master->flags)) {
784 		/*
785 		 * Only max_slave_count will be scanned in a search,
786 		 * but it will start where it left off next search
787 		 * until all ids are identified and then it will start
788 		 * over.  A continued search will report the previous
789 		 * last id as the first id (provided it is still on the
790 		 * bus).
791 		 */
792 		dev_info(&dev->udev->dev, "%s: max_slave_count %d reached, "
793 			"will continue next search.\n", __func__,
794 			master->max_slave_count);
795 		set_bit(W1_WARN_MAX_COUNT, &master->flags);
796 	}
797 
798 search_out:
799 	mutex_unlock(&master->bus_mutex);
800 	kfree(buf);
801 
802 	for (i = 0; i < found; i++) /* run callback for all queued up IDs */
803 		callback(master, found_ids[i]);
804 	kfree(found_ids);
805 }
806 
807 #if 0
808 /*
809  * FIXME: if this disabled code is ever used in the future all ds_send_data()
810  * calls must be changed to use a DMAable buffer.
811  */
812 static int ds_match_access(struct ds_device *dev, u64 init)
813 {
814 	int err;
815 	struct ds_status st;
816 
817 	err = ds_send_data(dev, (unsigned char *)&init, sizeof(init));
818 	if (err)
819 		return err;
820 
821 	ds_wait_status(dev, &st);
822 
823 	err = ds_send_control(dev, COMM_MATCH_ACCESS | COMM_IM | COMM_RST, 0x0055);
824 	if (err)
825 		return err;
826 
827 	ds_wait_status(dev, &st);
828 
829 	return 0;
830 }
831 
832 static int ds_set_path(struct ds_device *dev, u64 init)
833 {
834 	int err;
835 	struct ds_status st;
836 	u8 buf[9];
837 
838 	memcpy(buf, &init, 8);
839 	buf[8] = BRANCH_MAIN;
840 
841 	err = ds_send_data(dev, buf, sizeof(buf));
842 	if (err)
843 		return err;
844 
845 	ds_wait_status(dev, &st);
846 
847 	err = ds_send_control(dev, COMM_SET_PATH | COMM_IM | COMM_RST, 0);
848 	if (err)
849 		return err;
850 
851 	ds_wait_status(dev, &st);
852 
853 	return 0;
854 }
855 
856 #endif  /*  0  */
857 
858 static u8 ds9490r_touch_bit(void *data, u8 bit)
859 {
860 	struct ds_device *dev = data;
861 
862 	if (ds_touch_bit(dev, bit, &dev->byte_buf))
863 		return 0;
864 
865 	return dev->byte_buf;
866 }
867 
868 #if 0
869 static void ds9490r_write_bit(void *data, u8 bit)
870 {
871 	struct ds_device *dev = data;
872 
873 	ds_write_bit(dev, bit);
874 }
875 
876 static u8 ds9490r_read_bit(void *data)
877 {
878 	struct ds_device *dev = data;
879 	int err;
880 
881 	err = ds_touch_bit(dev, 1, &dev->byte_buf);
882 	if (err)
883 		return 0;
884 
885 	return dev->byte_buf & 1;
886 }
887 #endif
888 
889 static void ds9490r_write_byte(void *data, u8 byte)
890 {
891 	struct ds_device *dev = data;
892 
893 	ds_write_byte(dev, byte);
894 }
895 
896 static u8 ds9490r_read_byte(void *data)
897 {
898 	struct ds_device *dev = data;
899 	int err;
900 
901 	err = ds_read_byte(dev, &dev->byte_buf);
902 	if (err)
903 		return 0;
904 
905 	return dev->byte_buf;
906 }
907 
908 static void ds9490r_write_block(void *data, const u8 *buf, int len)
909 {
910 	struct ds_device *dev = data;
911 	u8 *tbuf;
912 
913 	if (len <= 0)
914 		return;
915 
916 	tbuf = kmemdup(buf, len, GFP_KERNEL);
917 	if (!tbuf)
918 		return;
919 
920 	ds_write_block(dev, tbuf, len);
921 
922 	kfree(tbuf);
923 }
924 
925 static u8 ds9490r_read_block(void *data, u8 *buf, int len)
926 {
927 	struct ds_device *dev = data;
928 	int err;
929 	u8 *tbuf;
930 
931 	if (len <= 0)
932 		return 0;
933 
934 	tbuf = kmalloc(len, GFP_KERNEL);
935 	if (!tbuf)
936 		return 0;
937 
938 	err = ds_read_block(dev, tbuf, len);
939 	if (err >= 0)
940 		memcpy(buf, tbuf, len);
941 
942 	kfree(tbuf);
943 
944 	return err >= 0 ? len : 0;
945 }
946 
947 static u8 ds9490r_reset(void *data)
948 {
949 	struct ds_device *dev = data;
950 	int err;
951 
952 	err = ds_reset(dev);
953 	if (err)
954 		return 1;
955 
956 	return 0;
957 }
958 
959 static u8 ds9490r_set_pullup(void *data, int delay)
960 {
961 	struct ds_device *dev = data;
962 
963 	if (ds_set_pullup(dev, delay))
964 		return 1;
965 
966 	return 0;
967 }
968 
969 static int ds_w1_init(struct ds_device *dev)
970 {
971 	memset(&dev->master, 0, sizeof(struct w1_bus_master));
972 
973 	/* Reset the device as it can be in a bad state.
974 	 * This is necessary because a block write will wait for data
975 	 * to be placed in the output buffer and block any later
976 	 * commands which will keep accumulating and the device will
977 	 * not be idle.  Another case is removing the ds2490 module
978 	 * while a bus search is in progress, somehow a few commands
979 	 * get through, but the input transfers fail leaving data in
980 	 * the input buffer.  This will cause the next read to fail
981 	 * see the note in ds_recv_data.
982 	 */
983 	ds_reset_device(dev);
984 
985 	dev->master.data	= dev;
986 	dev->master.touch_bit	= &ds9490r_touch_bit;
987 	/* read_bit and write_bit in w1_bus_master are expected to set and
988 	 * sample the line level.  For write_bit that means it is expected to
989 	 * set it to that value and leave it there.  ds2490 only supports an
990 	 * individual time slot at the lowest level.  The requirement from
991 	 * pulling the bus state down to reading the state is 15us, something
992 	 * that isn't realistic on the USB bus anyway.
993 	dev->master.read_bit	= &ds9490r_read_bit;
994 	dev->master.write_bit	= &ds9490r_write_bit;
995 	*/
996 	dev->master.read_byte	= &ds9490r_read_byte;
997 	dev->master.write_byte	= &ds9490r_write_byte;
998 	dev->master.read_block	= &ds9490r_read_block;
999 	dev->master.write_block	= &ds9490r_write_block;
1000 	dev->master.reset_bus	= &ds9490r_reset;
1001 	dev->master.set_pullup	= &ds9490r_set_pullup;
1002 	dev->master.search	= &ds9490r_search;
1003 
1004 	return w1_add_master_device(&dev->master);
1005 }
1006 
1007 static void ds_w1_fini(struct ds_device *dev)
1008 {
1009 	w1_remove_master_device(&dev->master);
1010 }
1011 
1012 static int ds_probe(struct usb_interface *intf,
1013 		    const struct usb_device_id *udev_id)
1014 {
1015 	struct usb_device *udev = interface_to_usbdev(intf);
1016 	struct usb_endpoint_descriptor *endpoint;
1017 	struct usb_host_interface *iface_desc;
1018 	struct ds_device *dev;
1019 	int i, err, alt;
1020 
1021 	dev = kzalloc(sizeof(struct ds_device), GFP_KERNEL);
1022 	if (!dev)
1023 		return -ENOMEM;
1024 
1025 	dev->udev = usb_get_dev(udev);
1026 	if (!dev->udev) {
1027 		err = -ENOMEM;
1028 		goto err_out_free;
1029 	}
1030 	memset(dev->ep, 0, sizeof(dev->ep));
1031 
1032 	usb_set_intfdata(intf, dev);
1033 
1034 	err = usb_reset_configuration(dev->udev);
1035 	if (err) {
1036 		dev_err(&dev->udev->dev,
1037 			"Failed to reset configuration: err=%d.\n", err);
1038 		goto err_out_clear;
1039 	}
1040 
1041 	/* alternative 3, 1ms interrupt (greatly speeds search), 64 byte bulk */
1042 	alt = 3;
1043 	err = usb_set_interface(dev->udev,
1044 		intf->cur_altsetting->desc.bInterfaceNumber, alt);
1045 	if (err) {
1046 		dev_err(&dev->udev->dev, "Failed to set alternative setting %d "
1047 			"for %d interface: err=%d.\n", alt,
1048 			intf->cur_altsetting->desc.bInterfaceNumber, err);
1049 		goto err_out_clear;
1050 	}
1051 
1052 	iface_desc = intf->cur_altsetting;
1053 	if (iface_desc->desc.bNumEndpoints != NUM_EP-1) {
1054 		dev_err(&dev->udev->dev, "Num endpoints=%d. It is not DS9490R.\n",
1055 			iface_desc->desc.bNumEndpoints);
1056 		err = -EINVAL;
1057 		goto err_out_clear;
1058 	}
1059 
1060 	/*
1061 	 * This loop doesn'd show control 0 endpoint,
1062 	 * so we will fill only 1-3 endpoints entry.
1063 	 */
1064 	for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
1065 		endpoint = &iface_desc->endpoint[i].desc;
1066 
1067 		dev->ep[i+1] = endpoint->bEndpointAddress;
1068 #if 0
1069 		printk("%d: addr=%x, size=%d, dir=%s, type=%x\n",
1070 			i, endpoint->bEndpointAddress, le16_to_cpu(endpoint->wMaxPacketSize),
1071 			(endpoint->bEndpointAddress & USB_DIR_IN)?"IN":"OUT",
1072 			endpoint->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK);
1073 #endif
1074 	}
1075 
1076 	err = ds_w1_init(dev);
1077 	if (err)
1078 		goto err_out_clear;
1079 
1080 	mutex_lock(&ds_mutex);
1081 	list_add_tail(&dev->ds_entry, &ds_devices);
1082 	mutex_unlock(&ds_mutex);
1083 
1084 	return 0;
1085 
1086 err_out_clear:
1087 	usb_set_intfdata(intf, NULL);
1088 	usb_put_dev(dev->udev);
1089 err_out_free:
1090 	kfree(dev);
1091 	return err;
1092 }
1093 
1094 static void ds_disconnect(struct usb_interface *intf)
1095 {
1096 	struct ds_device *dev;
1097 
1098 	dev = usb_get_intfdata(intf);
1099 	if (!dev)
1100 		return;
1101 
1102 	mutex_lock(&ds_mutex);
1103 	list_del(&dev->ds_entry);
1104 	mutex_unlock(&ds_mutex);
1105 
1106 	ds_w1_fini(dev);
1107 
1108 	usb_set_intfdata(intf, NULL);
1109 
1110 	usb_put_dev(dev->udev);
1111 	kfree(dev);
1112 }
1113 
1114 static const struct usb_device_id ds_id_table[] = {
1115 	{ USB_DEVICE(0x04fa, 0x2490) },
1116 	{ },
1117 };
1118 MODULE_DEVICE_TABLE(usb, ds_id_table);
1119 
1120 static struct usb_driver ds_driver = {
1121 	.name =		"DS9490R",
1122 	.probe =	ds_probe,
1123 	.disconnect =	ds_disconnect,
1124 	.id_table =	ds_id_table,
1125 };
1126 module_usb_driver(ds_driver);
1127 
1128 MODULE_AUTHOR("Evgeniy Polyakov <zbr@ioremap.net>");
1129 MODULE_DESCRIPTION("DS2490 USB <-> W1 bus master driver (DS9490*)");
1130 MODULE_LICENSE("GPL");
1131