1 /* -------------------------------------------------------------------------
2 * i2c-algo-bit.c i2c driver algorithms for bit-shift adapters
3 * -------------------------------------------------------------------------
4 * Copyright (C) 1995-2000 Simon G. Vogl
5
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2 of the License, or
9 (at your option) any later version.
10
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
15 * ------------------------------------------------------------------------- */
16
17 /* With some changes from Frodo Looijaard <frodol@dds.nl>, Kyösti Mälkki
18 <kmalkki@cc.hut.fi> and Jean Delvare <jdelvare@suse.de> */
19
20 #include <linux/kernel.h>
21 #include <linux/module.h>
22 #include <linux/delay.h>
23 #include <linux/errno.h>
24 #include <linux/sched.h>
25 #include <linux/i2c.h>
26 #include <linux/i2c-algo-bit.h>
27
28
29 /* ----- global defines ----------------------------------------------- */
30
31 #ifdef DEBUG
32 #define bit_dbg(level, dev, format, args...) \
33 do { \
34 if (i2c_debug >= level) \
35 dev_dbg(dev, format, ##args); \
36 } while (0)
37 #else
38 #define bit_dbg(level, dev, format, args...) \
39 do {} while (0)
40 #endif /* DEBUG */
41
42 /* ----- global variables --------------------------------------------- */
43
44 static int bit_test; /* see if the line-setting functions work */
45 module_param(bit_test, int, S_IRUGO);
46 MODULE_PARM_DESC(bit_test, "lines testing - 0 off; 1 report; 2 fail if stuck");
47
48 #ifdef DEBUG
49 static int i2c_debug = 1;
50 module_param(i2c_debug, int, S_IRUGO | S_IWUSR);
51 MODULE_PARM_DESC(i2c_debug,
52 "debug level - 0 off; 1 normal; 2 verbose; 3 very verbose");
53 #endif
54
55 /* --- setting states on the bus with the right timing: --------------- */
56
57 #define setsda(adap, val) adap->setsda(adap->data, val)
58 #define setscl(adap, val) adap->setscl(adap->data, val)
59 #define getsda(adap) adap->getsda(adap->data)
60 #define getscl(adap) adap->getscl(adap->data)
61
sdalo(struct i2c_algo_bit_data * adap)62 static inline void sdalo(struct i2c_algo_bit_data *adap)
63 {
64 setsda(adap, 0);
65 udelay((adap->udelay + 1) / 2);
66 }
67
sdahi(struct i2c_algo_bit_data * adap)68 static inline void sdahi(struct i2c_algo_bit_data *adap)
69 {
70 setsda(adap, 1);
71 udelay((adap->udelay + 1) / 2);
72 }
73
scllo(struct i2c_algo_bit_data * adap)74 static inline void scllo(struct i2c_algo_bit_data *adap)
75 {
76 setscl(adap, 0);
77 udelay(adap->udelay / 2);
78 }
79
80 /*
81 * Raise scl line, and do checking for delays. This is necessary for slower
82 * devices.
83 */
sclhi(struct i2c_algo_bit_data * adap)84 static int sclhi(struct i2c_algo_bit_data *adap)
85 {
86 unsigned long start;
87
88 setscl(adap, 1);
89
90 /* Not all adapters have scl sense line... */
91 if (!adap->getscl)
92 goto done;
93
94 start = jiffies;
95 while (!getscl(adap)) {
96 /* This hw knows how to read the clock line, so we wait
97 * until it actually gets high. This is safer as some
98 * chips may hold it low ("clock stretching") while they
99 * are processing data internally.
100 */
101 if (time_after(jiffies, start + adap->timeout)) {
102 /* Test one last time, as we may have been preempted
103 * between last check and timeout test.
104 */
105 if (getscl(adap))
106 break;
107 return -ETIMEDOUT;
108 }
109 cpu_relax();
110 }
111 #ifdef DEBUG
112 if (jiffies != start && i2c_debug >= 3)
113 pr_debug("i2c-algo-bit: needed %ld jiffies for SCL to go high\n",
114 jiffies - start);
115 #endif
116
117 done:
118 udelay(adap->udelay);
119 return 0;
120 }
121
122
123 /* --- other auxiliary functions -------------------------------------- */
i2c_start(struct i2c_algo_bit_data * adap)124 static void i2c_start(struct i2c_algo_bit_data *adap)
125 {
126 /* assert: scl, sda are high */
127 setsda(adap, 0);
128 udelay(adap->udelay);
129 scllo(adap);
130 }
131
i2c_repstart(struct i2c_algo_bit_data * adap)132 static void i2c_repstart(struct i2c_algo_bit_data *adap)
133 {
134 /* assert: scl is low */
135 sdahi(adap);
136 sclhi(adap);
137 setsda(adap, 0);
138 udelay(adap->udelay);
139 scllo(adap);
140 }
141
142
i2c_stop(struct i2c_algo_bit_data * adap)143 static void i2c_stop(struct i2c_algo_bit_data *adap)
144 {
145 /* assert: scl is low */
146 sdalo(adap);
147 sclhi(adap);
148 setsda(adap, 1);
149 udelay(adap->udelay);
150 }
151
152
153
154 /* send a byte without start cond., look for arbitration,
155 check ackn. from slave */
156 /* returns:
157 * 1 if the device acknowledged
158 * 0 if the device did not ack
159 * -ETIMEDOUT if an error occurred (while raising the scl line)
160 */
i2c_outb(struct i2c_adapter * i2c_adap,unsigned char c)161 static int i2c_outb(struct i2c_adapter *i2c_adap, unsigned char c)
162 {
163 int i;
164 int sb;
165 int ack;
166 struct i2c_algo_bit_data *adap = i2c_adap->algo_data;
167
168 /* assert: scl is low */
169 for (i = 7; i >= 0; i--) {
170 sb = (c >> i) & 1;
171 setsda(adap, sb);
172 udelay((adap->udelay + 1) / 2);
173 if (sclhi(adap) < 0) { /* timed out */
174 bit_dbg(1, &i2c_adap->dev,
175 "i2c_outb: 0x%02x, timeout at bit #%d\n",
176 (int)c, i);
177 return -ETIMEDOUT;
178 }
179 /* FIXME do arbitration here:
180 * if (sb && !getsda(adap)) -> ouch! Get out of here.
181 *
182 * Report a unique code, so higher level code can retry
183 * the whole (combined) message and *NOT* issue STOP.
184 */
185 scllo(adap);
186 }
187 sdahi(adap);
188 if (sclhi(adap) < 0) { /* timeout */
189 bit_dbg(1, &i2c_adap->dev,
190 "i2c_outb: 0x%02x, timeout at ack\n", (int)c);
191 return -ETIMEDOUT;
192 }
193
194 /* read ack: SDA should be pulled down by slave, or it may
195 * NAK (usually to report problems with the data we wrote).
196 */
197 ack = !getsda(adap); /* ack: sda is pulled low -> success */
198 bit_dbg(2, &i2c_adap->dev, "i2c_outb: 0x%02x %s\n", (int)c,
199 ack ? "A" : "NA");
200
201 scllo(adap);
202 return ack;
203 /* assert: scl is low (sda undef) */
204 }
205
206
i2c_inb(struct i2c_adapter * i2c_adap)207 static int i2c_inb(struct i2c_adapter *i2c_adap)
208 {
209 /* read byte via i2c port, without start/stop sequence */
210 /* acknowledge is sent in i2c_read. */
211 int i;
212 unsigned char indata = 0;
213 struct i2c_algo_bit_data *adap = i2c_adap->algo_data;
214
215 /* assert: scl is low */
216 sdahi(adap);
217 for (i = 0; i < 8; i++) {
218 if (sclhi(adap) < 0) { /* timeout */
219 bit_dbg(1, &i2c_adap->dev,
220 "i2c_inb: timeout at bit #%d\n",
221 7 - i);
222 return -ETIMEDOUT;
223 }
224 indata *= 2;
225 if (getsda(adap))
226 indata |= 0x01;
227 setscl(adap, 0);
228 udelay(i == 7 ? adap->udelay / 2 : adap->udelay);
229 }
230 /* assert: scl is low */
231 return indata;
232 }
233
234 /*
235 * Sanity check for the adapter hardware - check the reaction of
236 * the bus lines only if it seems to be idle.
237 */
test_bus(struct i2c_adapter * i2c_adap)238 static int test_bus(struct i2c_adapter *i2c_adap)
239 {
240 struct i2c_algo_bit_data *adap = i2c_adap->algo_data;
241 const char *name = i2c_adap->name;
242 int scl, sda, ret;
243
244 if (adap->pre_xfer) {
245 ret = adap->pre_xfer(i2c_adap);
246 if (ret < 0)
247 return -ENODEV;
248 }
249
250 if (adap->getscl == NULL)
251 pr_info("%s: Testing SDA only, SCL is not readable\n", name);
252
253 sda = getsda(adap);
254 scl = (adap->getscl == NULL) ? 1 : getscl(adap);
255 if (!scl || !sda) {
256 printk(KERN_WARNING
257 "%s: bus seems to be busy (scl=%d, sda=%d)\n",
258 name, scl, sda);
259 goto bailout;
260 }
261
262 sdalo(adap);
263 sda = getsda(adap);
264 scl = (adap->getscl == NULL) ? 1 : getscl(adap);
265 if (sda) {
266 printk(KERN_WARNING "%s: SDA stuck high!\n", name);
267 goto bailout;
268 }
269 if (!scl) {
270 printk(KERN_WARNING
271 "%s: SCL unexpected low while pulling SDA low!\n",
272 name);
273 goto bailout;
274 }
275
276 sdahi(adap);
277 sda = getsda(adap);
278 scl = (adap->getscl == NULL) ? 1 : getscl(adap);
279 if (!sda) {
280 printk(KERN_WARNING "%s: SDA stuck low!\n", name);
281 goto bailout;
282 }
283 if (!scl) {
284 printk(KERN_WARNING
285 "%s: SCL unexpected low while pulling SDA high!\n",
286 name);
287 goto bailout;
288 }
289
290 scllo(adap);
291 sda = getsda(adap);
292 scl = (adap->getscl == NULL) ? 0 : getscl(adap);
293 if (scl) {
294 printk(KERN_WARNING "%s: SCL stuck high!\n", name);
295 goto bailout;
296 }
297 if (!sda) {
298 printk(KERN_WARNING
299 "%s: SDA unexpected low while pulling SCL low!\n",
300 name);
301 goto bailout;
302 }
303
304 sclhi(adap);
305 sda = getsda(adap);
306 scl = (adap->getscl == NULL) ? 1 : getscl(adap);
307 if (!scl) {
308 printk(KERN_WARNING "%s: SCL stuck low!\n", name);
309 goto bailout;
310 }
311 if (!sda) {
312 printk(KERN_WARNING
313 "%s: SDA unexpected low while pulling SCL high!\n",
314 name);
315 goto bailout;
316 }
317
318 if (adap->post_xfer)
319 adap->post_xfer(i2c_adap);
320
321 pr_info("%s: Test OK\n", name);
322 return 0;
323 bailout:
324 sdahi(adap);
325 sclhi(adap);
326
327 if (adap->post_xfer)
328 adap->post_xfer(i2c_adap);
329
330 return -ENODEV;
331 }
332
333 /* ----- Utility functions
334 */
335
336 /* try_address tries to contact a chip for a number of
337 * times before it gives up.
338 * return values:
339 * 1 chip answered
340 * 0 chip did not answer
341 * -x transmission error
342 */
try_address(struct i2c_adapter * i2c_adap,unsigned char addr,int retries)343 static int try_address(struct i2c_adapter *i2c_adap,
344 unsigned char addr, int retries)
345 {
346 struct i2c_algo_bit_data *adap = i2c_adap->algo_data;
347 int i, ret = 0;
348
349 for (i = 0; i <= retries; i++) {
350 ret = i2c_outb(i2c_adap, addr);
351 if (ret == 1 || i == retries)
352 break;
353 bit_dbg(3, &i2c_adap->dev, "emitting stop condition\n");
354 i2c_stop(adap);
355 udelay(adap->udelay);
356 yield();
357 bit_dbg(3, &i2c_adap->dev, "emitting start condition\n");
358 i2c_start(adap);
359 }
360 if (i && ret)
361 bit_dbg(1, &i2c_adap->dev,
362 "Used %d tries to %s client at 0x%02x: %s\n", i + 1,
363 addr & 1 ? "read from" : "write to", addr >> 1,
364 ret == 1 ? "success" : "failed, timeout?");
365 return ret;
366 }
367
sendbytes(struct i2c_adapter * i2c_adap,struct i2c_msg * msg)368 static int sendbytes(struct i2c_adapter *i2c_adap, struct i2c_msg *msg)
369 {
370 const unsigned char *temp = msg->buf;
371 int count = msg->len;
372 unsigned short nak_ok = msg->flags & I2C_M_IGNORE_NAK;
373 int retval;
374 int wrcount = 0;
375
376 while (count > 0) {
377 retval = i2c_outb(i2c_adap, *temp);
378
379 /* OK/ACK; or ignored NAK */
380 if ((retval > 0) || (nak_ok && (retval == 0))) {
381 count--;
382 temp++;
383 wrcount++;
384
385 /* A slave NAKing the master means the slave didn't like
386 * something about the data it saw. For example, maybe
387 * the SMBus PEC was wrong.
388 */
389 } else if (retval == 0) {
390 dev_err(&i2c_adap->dev, "sendbytes: NAK bailout.\n");
391 return -EIO;
392
393 /* Timeout; or (someday) lost arbitration
394 *
395 * FIXME Lost ARB implies retrying the transaction from
396 * the first message, after the "winning" master issues
397 * its STOP. As a rule, upper layer code has no reason
398 * to know or care about this ... it is *NOT* an error.
399 */
400 } else {
401 dev_err(&i2c_adap->dev, "sendbytes: error %d\n",
402 retval);
403 return retval;
404 }
405 }
406 return wrcount;
407 }
408
acknak(struct i2c_adapter * i2c_adap,int is_ack)409 static int acknak(struct i2c_adapter *i2c_adap, int is_ack)
410 {
411 struct i2c_algo_bit_data *adap = i2c_adap->algo_data;
412
413 /* assert: sda is high */
414 if (is_ack) /* send ack */
415 setsda(adap, 0);
416 udelay((adap->udelay + 1) / 2);
417 if (sclhi(adap) < 0) { /* timeout */
418 dev_err(&i2c_adap->dev, "readbytes: ack/nak timeout\n");
419 return -ETIMEDOUT;
420 }
421 scllo(adap);
422 return 0;
423 }
424
readbytes(struct i2c_adapter * i2c_adap,struct i2c_msg * msg)425 static int readbytes(struct i2c_adapter *i2c_adap, struct i2c_msg *msg)
426 {
427 int inval;
428 int rdcount = 0; /* counts bytes read */
429 unsigned char *temp = msg->buf;
430 int count = msg->len;
431 const unsigned flags = msg->flags;
432
433 while (count > 0) {
434 inval = i2c_inb(i2c_adap);
435 if (inval >= 0) {
436 *temp = inval;
437 rdcount++;
438 } else { /* read timed out */
439 break;
440 }
441
442 temp++;
443 count--;
444
445 /* Some SMBus transactions require that we receive the
446 transaction length as the first read byte. */
447 if (rdcount == 1 && (flags & I2C_M_RECV_LEN)) {
448 if (inval <= 0 || inval > I2C_SMBUS_BLOCK_MAX) {
449 if (!(flags & I2C_M_NO_RD_ACK))
450 acknak(i2c_adap, 0);
451 dev_err(&i2c_adap->dev,
452 "readbytes: invalid block length (%d)\n",
453 inval);
454 return -EPROTO;
455 }
456 /* The original count value accounts for the extra
457 bytes, that is, either 1 for a regular transaction,
458 or 2 for a PEC transaction. */
459 count += inval;
460 msg->len += inval;
461 }
462
463 bit_dbg(2, &i2c_adap->dev, "readbytes: 0x%02x %s\n",
464 inval,
465 (flags & I2C_M_NO_RD_ACK)
466 ? "(no ack/nak)"
467 : (count ? "A" : "NA"));
468
469 if (!(flags & I2C_M_NO_RD_ACK)) {
470 inval = acknak(i2c_adap, count);
471 if (inval < 0)
472 return inval;
473 }
474 }
475 return rdcount;
476 }
477
478 /* doAddress initiates the transfer by generating the start condition (in
479 * try_address) and transmits the address in the necessary format to handle
480 * reads, writes as well as 10bit-addresses.
481 * returns:
482 * 0 everything went okay, the chip ack'ed, or IGNORE_NAK flag was set
483 * -x an error occurred (like: -ENXIO if the device did not answer, or
484 * -ETIMEDOUT, for example if the lines are stuck...)
485 */
bit_doAddress(struct i2c_adapter * i2c_adap,struct i2c_msg * msg)486 static int bit_doAddress(struct i2c_adapter *i2c_adap, struct i2c_msg *msg)
487 {
488 unsigned short flags = msg->flags;
489 unsigned short nak_ok = msg->flags & I2C_M_IGNORE_NAK;
490 struct i2c_algo_bit_data *adap = i2c_adap->algo_data;
491
492 unsigned char addr;
493 int ret, retries;
494
495 retries = nak_ok ? 0 : i2c_adap->retries;
496
497 if (flags & I2C_M_TEN) {
498 /* a ten bit address */
499 addr = 0xf0 | ((msg->addr >> 7) & 0x06);
500 bit_dbg(2, &i2c_adap->dev, "addr0: %d\n", addr);
501 /* try extended address code...*/
502 ret = try_address(i2c_adap, addr, retries);
503 if ((ret != 1) && !nak_ok) {
504 dev_err(&i2c_adap->dev,
505 "died at extended address code\n");
506 return -ENXIO;
507 }
508 /* the remaining 8 bit address */
509 ret = i2c_outb(i2c_adap, msg->addr & 0xff);
510 if ((ret != 1) && !nak_ok) {
511 /* the chip did not ack / xmission error occurred */
512 dev_err(&i2c_adap->dev, "died at 2nd address code\n");
513 return -ENXIO;
514 }
515 if (flags & I2C_M_RD) {
516 bit_dbg(3, &i2c_adap->dev,
517 "emitting repeated start condition\n");
518 i2c_repstart(adap);
519 /* okay, now switch into reading mode */
520 addr |= 0x01;
521 ret = try_address(i2c_adap, addr, retries);
522 if ((ret != 1) && !nak_ok) {
523 dev_err(&i2c_adap->dev,
524 "died at repeated address code\n");
525 return -EIO;
526 }
527 }
528 } else { /* normal 7bit address */
529 addr = i2c_8bit_addr_from_msg(msg);
530 if (flags & I2C_M_REV_DIR_ADDR)
531 addr ^= 1;
532 ret = try_address(i2c_adap, addr, retries);
533 if ((ret != 1) && !nak_ok)
534 return -ENXIO;
535 }
536
537 return 0;
538 }
539
bit_xfer(struct i2c_adapter * i2c_adap,struct i2c_msg msgs[],int num)540 static int bit_xfer(struct i2c_adapter *i2c_adap,
541 struct i2c_msg msgs[], int num)
542 {
543 struct i2c_msg *pmsg;
544 struct i2c_algo_bit_data *adap = i2c_adap->algo_data;
545 int i, ret;
546 unsigned short nak_ok;
547
548 if (adap->pre_xfer) {
549 ret = adap->pre_xfer(i2c_adap);
550 if (ret < 0)
551 return ret;
552 }
553
554 bit_dbg(3, &i2c_adap->dev, "emitting start condition\n");
555 i2c_start(adap);
556 for (i = 0; i < num; i++) {
557 pmsg = &msgs[i];
558 nak_ok = pmsg->flags & I2C_M_IGNORE_NAK;
559 if (!(pmsg->flags & I2C_M_NOSTART)) {
560 if (i) {
561 if (msgs[i - 1].flags & I2C_M_STOP) {
562 bit_dbg(3, &i2c_adap->dev,
563 "emitting enforced stop/start condition\n");
564 i2c_stop(adap);
565 i2c_start(adap);
566 } else {
567 bit_dbg(3, &i2c_adap->dev,
568 "emitting repeated start condition\n");
569 i2c_repstart(adap);
570 }
571 }
572 ret = bit_doAddress(i2c_adap, pmsg);
573 if ((ret != 0) && !nak_ok) {
574 bit_dbg(1, &i2c_adap->dev,
575 "NAK from device addr 0x%02x msg #%d\n",
576 msgs[i].addr, i);
577 goto bailout;
578 }
579 }
580 if (pmsg->flags & I2C_M_RD) {
581 /* read bytes into buffer*/
582 ret = readbytes(i2c_adap, pmsg);
583 if (ret >= 1)
584 bit_dbg(2, &i2c_adap->dev, "read %d byte%s\n",
585 ret, ret == 1 ? "" : "s");
586 if (ret < pmsg->len) {
587 if (ret >= 0)
588 ret = -EIO;
589 goto bailout;
590 }
591 } else {
592 /* write bytes from buffer */
593 ret = sendbytes(i2c_adap, pmsg);
594 if (ret >= 1)
595 bit_dbg(2, &i2c_adap->dev, "wrote %d byte%s\n",
596 ret, ret == 1 ? "" : "s");
597 if (ret < pmsg->len) {
598 if (ret >= 0)
599 ret = -EIO;
600 goto bailout;
601 }
602 }
603 }
604 ret = i;
605
606 bailout:
607 bit_dbg(3, &i2c_adap->dev, "emitting stop condition\n");
608 i2c_stop(adap);
609
610 if (adap->post_xfer)
611 adap->post_xfer(i2c_adap);
612 return ret;
613 }
614
bit_func(struct i2c_adapter * adap)615 static u32 bit_func(struct i2c_adapter *adap)
616 {
617 return I2C_FUNC_I2C | I2C_FUNC_NOSTART | I2C_FUNC_SMBUS_EMUL |
618 I2C_FUNC_SMBUS_READ_BLOCK_DATA |
619 I2C_FUNC_SMBUS_BLOCK_PROC_CALL |
620 I2C_FUNC_10BIT_ADDR | I2C_FUNC_PROTOCOL_MANGLING;
621 }
622
623
624 /* -----exported algorithm data: ------------------------------------- */
625
626 const struct i2c_algorithm i2c_bit_algo = {
627 .master_xfer = bit_xfer,
628 .functionality = bit_func,
629 };
630 EXPORT_SYMBOL(i2c_bit_algo);
631
632 static const struct i2c_adapter_quirks i2c_bit_quirk_no_clk_stretch = {
633 .flags = I2C_AQ_NO_CLK_STRETCH,
634 };
635
636 /*
637 * registering functions to load algorithms at runtime
638 */
__i2c_bit_add_bus(struct i2c_adapter * adap,int (* add_adapter)(struct i2c_adapter *))639 static int __i2c_bit_add_bus(struct i2c_adapter *adap,
640 int (*add_adapter)(struct i2c_adapter *))
641 {
642 struct i2c_algo_bit_data *bit_adap = adap->algo_data;
643 int ret;
644
645 if (bit_test) {
646 ret = test_bus(adap);
647 if (bit_test >= 2 && ret < 0)
648 return -ENODEV;
649 }
650
651 /* register new adapter to i2c module... */
652 adap->algo = &i2c_bit_algo;
653 adap->retries = 3;
654 if (bit_adap->getscl == NULL)
655 adap->quirks = &i2c_bit_quirk_no_clk_stretch;
656
657 /*
658 * We tried forcing SCL/SDA to an initial state here. But that caused a
659 * regression, sadly. Check Bugzilla #200045 for details.
660 */
661
662 ret = add_adapter(adap);
663 if (ret < 0)
664 return ret;
665
666 /* Complain if SCL can't be read */
667 if (bit_adap->getscl == NULL) {
668 dev_warn(&adap->dev, "Not I2C compliant: can't read SCL\n");
669 dev_warn(&adap->dev, "Bus may be unreliable\n");
670 }
671 return 0;
672 }
673
i2c_bit_add_bus(struct i2c_adapter * adap)674 int i2c_bit_add_bus(struct i2c_adapter *adap)
675 {
676 return __i2c_bit_add_bus(adap, i2c_add_adapter);
677 }
678 EXPORT_SYMBOL(i2c_bit_add_bus);
679
i2c_bit_add_numbered_bus(struct i2c_adapter * adap)680 int i2c_bit_add_numbered_bus(struct i2c_adapter *adap)
681 {
682 return __i2c_bit_add_bus(adap, i2c_add_numbered_adapter);
683 }
684 EXPORT_SYMBOL(i2c_bit_add_numbered_bus);
685
686 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
687 MODULE_DESCRIPTION("I2C-Bus bit-banging algorithm");
688 MODULE_LICENSE("GPL");
689