xref: /freebsd/usr.sbin/i2c/i2c.c (revision eb69d1f144a6fcc765d1b9d44a5ae8082353e70b)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (C) 2008-2009 Semihalf, Michal Hajduk and Bartlomiej Sieka
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28 
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
31 
32 #include <err.h>
33 #include <errno.h>
34 #include <sysexits.h>
35 #include <fcntl.h>
36 #include <stdio.h>
37 #include <stdlib.h>
38 #include <string.h>
39 #include <stdarg.h>
40 #include <unistd.h>
41 #include <sys/ioctl.h>
42 
43 #include <dev/iicbus/iic.h>
44 
45 #define	I2C_DEV			"/dev/iic0"
46 #define	I2C_MODE_NOTSET		0
47 #define	I2C_MODE_NONE		1
48 #define	I2C_MODE_STOP_START	2
49 #define	I2C_MODE_REPEATED_START	3
50 
51 struct options {
52 	int	width;
53 	int	count;
54 	int	verbose;
55 	int	addr_set;
56 	int	binary;
57 	int	scan;
58 	int	skip;
59 	int	reset;
60 	int	mode;
61 	char	dir;
62 	uint32_t	addr;
63 	uint32_t	off;
64 };
65 
66 struct skip_range {
67 	int	start;
68 	int	end;
69 };
70 
71 __dead2 static void
72 usage(void)
73 {
74 
75 	fprintf(stderr, "usage: %s -a addr [-f device] [-d [r|w]] [-o offset] "
76 	    "[-w [0|8|16]] [-c count] [-m [ss|rs|no]] [-b] [-v]\n",
77 	    getprogname());
78 	fprintf(stderr, "       %s -s [-f device] [-n skip_addr] -v\n",
79 	    getprogname());
80 	fprintf(stderr, "       %s -r [-f device] -v\n", getprogname());
81 	exit(EX_USAGE);
82 }
83 
84 static struct skip_range
85 skip_get_range(char *skip_addr)
86 {
87 	struct skip_range addr_range;
88 	char *token;
89 
90 	addr_range.start = 0;
91 	addr_range.end = 0;
92 
93 	token = strsep(&skip_addr, "..");
94 	if (token) {
95 		addr_range.start = strtoul(token, 0, 16);
96 		token = strsep(&skip_addr, "..");
97 		if ((token != NULL) && !atoi(token)) {
98 			token = strsep(&skip_addr, "..");
99 			if (token)
100 				addr_range.end = strtoul(token, 0, 16);
101 		}
102 	}
103 
104 	return (addr_range);
105 }
106 
107 /* Parse the string to get hex 7 bits addresses */
108 static int
109 skip_get_tokens(char *skip_addr, int *sk_addr, int max_index)
110 {
111 	char *token;
112 	int i;
113 
114 	for (i = 0; i < max_index; i++) {
115 		token = strsep(&skip_addr, ":");
116 		if (token == NULL)
117 			break;
118 		sk_addr[i] = strtoul(token, 0, 16);
119 	}
120 	return (i);
121 }
122 
123 static int
124 scan_bus(struct iiccmd cmd, char *dev, int skip, char *skip_addr)
125 {
126 	struct iic_msg rdmsg;
127 	struct iic_rdwr_data rdwrdata;
128 	struct skip_range addr_range = { 0, 0 };
129 	int *tokens, fd, error, i, index, j;
130 	int len = 0, do_skip = 0, no_range = 1, num_found = 0, use_read_xfer = 0;
131 	uint8_t rdbyte;
132 
133 	fd = open(dev, O_RDWR);
134 	if (fd == -1) {
135 		fprintf(stderr, "Error opening I2C controller (%s) for "
136 		    "scanning: %s\n", dev, strerror(errno));
137 		return (EX_NOINPUT);
138 	}
139 
140 	if (skip) {
141 		len = strlen(skip_addr);
142 		if (strstr(skip_addr, "..") != NULL) {
143 			addr_range = skip_get_range(skip_addr);
144 			no_range = 0;
145 		} else {
146 			tokens = (int *)malloc((len / 2 + 1) * sizeof(int));
147 			if (tokens == NULL) {
148 				fprintf(stderr, "Error allocating tokens "
149 				    "buffer\n");
150 				error = -1;
151 				goto out;
152 			}
153 			index = skip_get_tokens(skip_addr, tokens,
154 			    len / 2 + 1);
155 		}
156 
157 		if (!no_range && (addr_range.start > addr_range.end)) {
158 			fprintf(stderr, "Skip address out of range\n");
159 			error = -1;
160 			goto out;
161 		}
162 	}
163 
164 	printf("Scanning I2C devices on %s: ", dev);
165 
166 start_over:
167 	if (use_read_xfer) {
168 		fprintf(stderr,
169 		    "Hardware may not support START/STOP scanning; "
170 		    "trying less-reliable read method.\n");
171 	}
172 
173 	for (i = 1; i < 127; i++) {
174 
175 		if (skip && ( addr_range.start < addr_range.end)) {
176 			if (i >= addr_range.start && i <= addr_range.end)
177 				continue;
178 
179 		} else if (skip && no_range)
180 			for (j = 0; j < index; j++) {
181 				if (tokens[j] == i) {
182 					do_skip = 1;
183 					break;
184 				}
185 			}
186 
187 		if (do_skip) {
188 			do_skip = 0;
189 			continue;
190 		}
191 
192 		cmd.slave = i << 1;
193 		cmd.last = 1;
194 		cmd.count = 0;
195 		error = ioctl(fd, I2CRSTCARD, &cmd);
196 		if (error) {
197 			fprintf(stderr, "Controller reset failed\n");
198 			goto out;
199 		}
200 		if (use_read_xfer) {
201 			rdmsg.buf = &rdbyte;
202 			rdmsg.len = 1;
203 			rdmsg.flags = IIC_M_RD;
204 			rdmsg.slave = i << 1;
205 			rdwrdata.msgs = &rdmsg;
206 			rdwrdata.nmsgs = 1;
207 			error = ioctl(fd, I2CRDWR, &rdwrdata);
208 		} else {
209 			cmd.slave = i << 1;
210 			cmd.last = 1;
211 			error = ioctl(fd, I2CSTART, &cmd);
212 			if (errno == ENODEV || errno == EOPNOTSUPP) {
213 				/* If START not supported try reading. */
214 				use_read_xfer = 1;
215 				goto start_over;
216 			}
217 			ioctl(fd, I2CSTOP);
218 		}
219 		if (error == 0) {
220 			++num_found;
221 			printf("%02x ", i);
222 		}
223 	}
224 
225 	/*
226 	 * If we found nothing, maybe START is not supported and returns a
227 	 * generic error code such as EIO or ENXIO, so try again using reads.
228 	 */
229 	if (num_found == 0) {
230 		if (!use_read_xfer) {
231 			use_read_xfer = 1;
232 			goto start_over;
233 		}
234 		printf("<none found>");
235 	}
236 	printf("\n");
237 
238 	error = ioctl(fd, I2CRSTCARD, &cmd);
239 out:
240 	close(fd);
241 	if (skip && no_range)
242 		free(tokens);
243 
244 	if (error) {
245 		fprintf(stderr, "Error scanning I2C controller (%s): %s\n",
246 		    dev, strerror(errno));
247 		return (EX_NOINPUT);
248 	} else
249 		return (EX_OK);
250 }
251 
252 static int
253 reset_bus(struct iiccmd cmd, char *dev)
254 {
255 	int fd, error;
256 
257 	fd = open(dev, O_RDWR);
258 	if (fd == -1) {
259 		fprintf(stderr, "Error opening I2C controller (%s) for "
260 		    "resetting: %s\n", dev, strerror(errno));
261 		return (EX_NOINPUT);
262 	}
263 
264 	printf("Resetting I2C controller on %s: ", dev);
265 	error = ioctl(fd, I2CRSTCARD, &cmd);
266 	close (fd);
267 
268 	if (error) {
269 		printf("error: %s\n", strerror(errno));
270 		return (EX_IOERR);
271 	} else {
272 		printf("OK\n");
273 		return (EX_OK);
274 	}
275 }
276 
277 static char *
278 prepare_buf(int size, uint32_t off)
279 {
280 	char *buf;
281 
282 	buf = malloc(size);
283 	if (buf == NULL)
284 		return (buf);
285 
286 	if (size == 1)
287 		buf[0] = off & 0xff;
288 	else if (size == 2) {
289 		buf[0] = (off >> 8) & 0xff;
290 		buf[1] = off & 0xff;
291 	}
292 
293 	return (buf);
294 }
295 
296 static int
297 i2c_write(char *dev, struct options i2c_opt, char *i2c_buf)
298 {
299 	struct iiccmd cmd;
300 	int ch, i, error, fd, bufsize;
301 	char *err_msg, *buf;
302 
303 	/*
304 	 * Read data to be written to the chip from stdin
305 	 */
306 	if (i2c_opt.verbose && !i2c_opt.binary)
307 		fprintf(stderr, "Enter %u bytes of data: ", i2c_opt.count);
308 
309 	for (i = 0; i < i2c_opt.count; i++) {
310 		ch = getchar();
311 		if (ch == EOF) {
312 			free(i2c_buf);
313 			err(1, "not enough data, exiting\n");
314 		}
315 		i2c_buf[i] = ch;
316 	}
317 
318 	fd = open(dev, O_RDWR);
319 	if (fd == -1) {
320 		free(i2c_buf);
321 		err(1, "open failed");
322 	}
323 
324 	cmd.slave = i2c_opt.addr;
325 	error = ioctl(fd, I2CSTART, &cmd);
326 	if (error == -1) {
327 		err_msg = "ioctl: error sending start condition";
328 		goto err1;
329 	}
330 
331 	if (i2c_opt.width) {
332 		bufsize = i2c_opt.width / 8;
333 		buf = prepare_buf(bufsize, i2c_opt.off);
334 		if (buf == NULL) {
335 			err_msg = "error: offset malloc";
336 			goto err1;
337 		}
338 	} else {
339 		bufsize = 0;
340 		buf = NULL;
341 	}
342 
343 	switch(i2c_opt.mode) {
344 	case I2C_MODE_STOP_START:
345 		/*
346 		 * Write offset where the data will go
347 		 */
348 		if (i2c_opt.width) {
349 			cmd.count = bufsize;
350 			cmd.buf = buf;
351 			error = ioctl(fd, I2CWRITE, &cmd);
352 			free(buf);
353 			if (error == -1) {
354 				err_msg = "ioctl: error writing offset";
355 				goto err1;
356 			}
357 		}
358 
359 		error = ioctl(fd, I2CSTOP);
360 		if (error == -1) {
361 			err_msg = "ioctl: error sending stop condition";
362 			goto err2;
363 		}
364 		cmd.slave = i2c_opt.addr;
365 		error = ioctl(fd, I2CSTART, &cmd);
366 		if (error == -1) {
367 			err_msg = "ioctl: error sending start condition";
368 			goto err1;
369 		}
370 
371 		/*
372 		 * Write the data
373 		 */
374 		cmd.count = i2c_opt.count;
375 		cmd.buf = i2c_buf;
376 		cmd.last = 0;
377 		error = ioctl(fd, I2CWRITE, &cmd);
378 		if (error == -1) {
379 			err_msg = "ioctl: error writing";
380 			goto err1;
381 		}
382 		break;
383 
384 	case I2C_MODE_REPEATED_START:
385 		/*
386 		 * Write offset where the data will go
387 		 */
388 		if (i2c_opt.width) {
389 			cmd.count = bufsize;
390 			cmd.buf = buf;
391 			error = ioctl(fd, I2CWRITE, &cmd);
392 			free(buf);
393 			if (error == -1) {
394 				err_msg = "ioctl: error writing offset";
395 				goto err1;
396 			}
397 		}
398 
399 		cmd.slave = i2c_opt.addr;
400 		error = ioctl(fd, I2CRPTSTART, &cmd);
401 		if (error == -1) {
402 			err_msg = "ioctl: error sending repeated start "
403 			    "condition";
404 			goto err1;
405 		}
406 
407 		/*
408 		 * Write the data
409 		 */
410 		cmd.count = i2c_opt.count;
411 		cmd.buf = i2c_buf;
412 		cmd.last = 0;
413 		error = ioctl(fd, I2CWRITE, &cmd);
414 		if (error == -1) {
415 			err_msg = "ioctl: error writing";
416 			goto err1;
417 		}
418 		break;
419 
420 	case I2C_MODE_NONE: /* fall through */
421 	default:
422 		buf = realloc(buf, bufsize + i2c_opt.count);
423 		if (buf == NULL) {
424 			err_msg = "error: data malloc";
425 			goto err1;
426 		}
427 
428 		memcpy(buf + bufsize, i2c_buf, i2c_opt.count);
429 		/*
430 		 * Write offset and data
431 		 */
432 		cmd.count = bufsize + i2c_opt.count;
433 		cmd.buf = buf;
434 		cmd.last = 0;
435 		error = ioctl(fd, I2CWRITE, &cmd);
436 		free(buf);
437 		if (error == -1) {
438 			err_msg = "ioctl: error writing";
439 			goto err1;
440 		}
441 		break;
442 	}
443 	error = ioctl(fd, I2CSTOP);
444 	if (error == -1) {
445 		err_msg = "ioctl: error sending stop condition";
446 		goto err2;
447 	}
448 
449 	close(fd);
450 	return (0);
451 
452 err1:
453 	error = ioctl(fd, I2CSTOP);
454 	if (error == -1)
455 		fprintf(stderr, "error sending stop condition\n");
456 err2:
457 	if (err_msg)
458 		fprintf(stderr, "%s\n", err_msg);
459 
460 	close(fd);
461 	return (1);
462 }
463 
464 static int
465 i2c_read(char *dev, struct options i2c_opt, char *i2c_buf)
466 {
467 	struct iiccmd cmd;
468 	int fd, error, bufsize;
469 	char *err_msg, data = 0, *buf;
470 
471 	fd = open(dev, O_RDWR);
472 	if (fd == -1)
473 		err(1, "open failed");
474 
475 	bzero(&cmd, sizeof(cmd));
476 
477 	if (i2c_opt.width) {
478 		cmd.slave = i2c_opt.addr;
479 		cmd.count = 1;
480 		cmd.last = 0;
481 		cmd.buf = &data;
482 		error = ioctl(fd, I2CSTART, &cmd);
483 		if (error == -1) {
484 			err_msg = "ioctl: error sending start condition";
485 			goto err1;
486 		}
487 		bufsize = i2c_opt.width / 8;
488 		buf = prepare_buf(bufsize, i2c_opt.off);
489 		if (buf == NULL) {
490 			err_msg = "error: offset malloc";
491 			goto err1;
492 		}
493 
494 		cmd.count = bufsize;
495 		cmd.buf = buf;
496 		cmd.last = 0;
497 		error = ioctl(fd, I2CWRITE, &cmd);
498 		free(buf);
499 		if (error == -1) {
500 			err_msg = "ioctl: error writing offset";
501 			goto err1;
502 		}
503 
504 		if (i2c_opt.mode == I2C_MODE_STOP_START) {
505 			error = ioctl(fd, I2CSTOP);
506 			if (error == -1) {
507 				err_msg = "error sending stop condition";
508 				goto err2;
509 			}
510 		}
511 	}
512 	cmd.slave = i2c_opt.addr | 1;
513 	cmd.count = 1;
514 	cmd.last = 0;
515 	cmd.buf = &data;
516 	if (i2c_opt.mode == I2C_MODE_STOP_START || i2c_opt.width == 0) {
517 		error = ioctl(fd, I2CSTART, &cmd);
518 		if (error == -1) {
519 			err_msg = "ioctl: error sending start condition";
520 			goto err2;
521 		}
522 	} else if (i2c_opt.mode == I2C_MODE_REPEATED_START) {
523 		error = ioctl(fd, I2CRPTSTART, &cmd);
524 		if (error == -1) {
525 			err_msg = "ioctl: error sending repeated start "
526 			    "condition";
527 			goto err1;
528 		}
529 	}
530 
531 	cmd.count = i2c_opt.count;
532 	cmd.buf = i2c_buf;
533 	cmd.last = 1;
534 	error = ioctl(fd, I2CREAD, &cmd);
535 	if (error == -1) {
536 		err_msg = "ioctl: error while reading";
537 		goto err1;
538 	}
539 
540 	error = ioctl(fd, I2CSTOP);
541 	if (error == -1) {
542 		err_msg = "error sending stop condtion\n";
543 		goto err2;
544 	}
545 
546 	close(fd);
547 	return (0);
548 
549 err1:
550 	error = ioctl(fd, I2CSTOP);
551 	if (error == -1)
552 		fprintf(stderr, "error sending stop condition\n");
553 err2:
554 	if (err_msg)
555 		fprintf(stderr, "%s\n", err_msg);
556 
557 	close(fd);
558 	return (1);
559 }
560 
561 int
562 main(int argc, char** argv)
563 {
564 	struct iiccmd cmd;
565 	struct options i2c_opt;
566 	char *dev, *skip_addr, *i2c_buf;
567 	int error, chunk_size, i, j, ch;
568 
569 	errno = 0;
570 	error = 0;
571 
572 	/* Line-break the output every chunk_size bytes */
573 	chunk_size = 16;
574 
575 	dev = I2C_DEV;
576 
577 	/* Default values */
578 	i2c_opt.addr_set = 0;
579 	i2c_opt.off = 0;
580 	i2c_opt.verbose = 0;
581 	i2c_opt.dir = 'r';	/* direction = read */
582 	i2c_opt.width = 8;
583 	i2c_opt.count = 1;
584 	i2c_opt.binary = 0;	/* ASCII text output */
585 	i2c_opt.scan = 0;	/* no bus scan */
586 	i2c_opt.skip = 0;	/* scan all addresses */
587 	i2c_opt.reset = 0;	/* no bus reset */
588 	i2c_opt.mode = I2C_MODE_NOTSET;
589 
590 	while ((ch = getopt(argc, argv, "a:f:d:o:w:c:m:n:sbvrh")) != -1) {
591 		switch(ch) {
592 		case 'a':
593 			i2c_opt.addr = (strtoul(optarg, 0, 16) << 1);
594 			if (i2c_opt.addr == 0 && errno == EINVAL)
595 				i2c_opt.addr_set = 0;
596 			else
597 				i2c_opt.addr_set = 1;
598 			break;
599 		case 'f':
600 			dev = optarg;
601 			break;
602 		case 'd':
603 			i2c_opt.dir = optarg[0];
604 			break;
605 		case 'o':
606 			i2c_opt.off = strtoul(optarg, 0, 16);
607 			if (i2c_opt.off == 0 && errno == EINVAL)
608 				error = 1;
609 			break;
610 		case 'w':
611 			i2c_opt.width = atoi(optarg);
612 			break;
613 		case 'c':
614 			i2c_opt.count = atoi(optarg);
615 			break;
616 		case 'm':
617 			if (!strcmp(optarg, "no"))
618 				i2c_opt.mode = I2C_MODE_NONE;
619 			else if (!strcmp(optarg, "ss"))
620 				i2c_opt.mode = I2C_MODE_STOP_START;
621 			else if (!strcmp(optarg, "rs"))
622 				i2c_opt.mode = I2C_MODE_REPEATED_START;
623 			else
624 				usage();
625 			break;
626 		case 'n':
627 			i2c_opt.skip = 1;
628 			skip_addr = optarg;
629 			break;
630 		case 's':
631 			i2c_opt.scan = 1;
632 			break;
633 		case 'b':
634 			i2c_opt.binary = 1;
635 			break;
636 		case 'v':
637 			i2c_opt.verbose = 1;
638 			break;
639 		case 'r':
640 			i2c_opt.reset = 1;
641 			break;
642 		case 'h':
643 		default:
644 			usage();
645 		}
646 	}
647 	argc -= optind;
648 	argv += optind;
649 
650 	/* Set default mode if option -m is not specified */
651 	if (i2c_opt.mode == I2C_MODE_NOTSET) {
652 		if (i2c_opt.dir == 'r')
653 			i2c_opt.mode = I2C_MODE_STOP_START;
654 		else if (i2c_opt.dir == 'w')
655 			i2c_opt.mode = I2C_MODE_NONE;
656 	}
657 
658 	/* Basic sanity check of command line arguments */
659 	if (i2c_opt.scan) {
660 		if (i2c_opt.addr_set)
661 			usage();
662 	} else if (i2c_opt.reset) {
663 		if (i2c_opt.addr_set)
664 			usage();
665 	} else if (error) {
666 		usage();
667 	} else if ((i2c_opt.dir == 'r' || i2c_opt.dir == 'w')) {
668 		if ((i2c_opt.addr_set == 0) ||
669 		    !(i2c_opt.width == 0 || i2c_opt.width == 8 ||
670 		    i2c_opt.width == 16))
671 		usage();
672 	}
673 
674 	if (i2c_opt.verbose)
675 		fprintf(stderr, "dev: %s, addr: 0x%x, r/w: %c, "
676 		    "offset: 0x%02x, width: %u, count: %u\n", dev,
677 		    i2c_opt.addr >> 1, i2c_opt.dir, i2c_opt.off,
678 		    i2c_opt.width, i2c_opt.count);
679 
680 	if (i2c_opt.scan)
681 		exit(scan_bus(cmd, dev, i2c_opt.skip, skip_addr));
682 
683 	if (i2c_opt.reset)
684 		exit(reset_bus(cmd, dev));
685 
686 	i2c_buf = malloc(i2c_opt.count);
687 	if (i2c_buf == NULL)
688 		err(1, "data malloc");
689 
690 	if (i2c_opt.dir == 'w') {
691 		error = i2c_write(dev, i2c_opt, i2c_buf);
692 		if (error) {
693 			free(i2c_buf);
694 			return (1);
695 		}
696 	}
697 	if (i2c_opt.dir == 'r') {
698 		error = i2c_read(dev, i2c_opt, i2c_buf);
699 		if (error) {
700 			free(i2c_buf);
701 			return (1);
702 		}
703 	}
704 
705 	if (i2c_opt.verbose)
706 		fprintf(stderr, "\nData %s (hex):\n", i2c_opt.dir == 'r' ?
707 		    "read" : "written");
708 
709 	i = 0;
710 	j = 0;
711 	while (i < i2c_opt.count) {
712 		if (i2c_opt.verbose || (i2c_opt.dir == 'r' &&
713 		    !i2c_opt.binary))
714 			fprintf (stderr, "%02hhx ", i2c_buf[i++]);
715 
716 		if (i2c_opt.dir == 'r' && i2c_opt.binary) {
717 			fprintf(stdout, "%c", i2c_buf[j++]);
718 			if(!i2c_opt.verbose)
719 				i++;
720 		}
721 		if (!i2c_opt.verbose && (i2c_opt.dir == 'w'))
722 			break;
723 		if ((i % chunk_size) == 0)
724 			fprintf(stderr, "\n");
725 	}
726 	if ((i % chunk_size) != 0)
727 		fprintf(stderr, "\n");
728 
729 	free(i2c_buf);
730 	return (0);
731 }
732