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Commit | Line | Data |
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cf978ab2 DB |
1 | /* ------------------------------------------------------------------------- |
2 | * i2c-algo-bit.c i2c driver algorithms for bit-shift adapters | |
3 | * ------------------------------------------------------------------------- | |
4 | * Copyright (C) 1995-2000 Simon G. Vogl | |
1da177e4 LT |
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 | You should have received a copy of the GNU General Public License | |
17 | along with this program; if not, write to the Free Software | |
cf978ab2 DB |
18 | Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
19 | * ------------------------------------------------------------------------- */ | |
1da177e4 | 20 | |
96de0e25 | 21 | /* With some changes from Frodo Looijaard <frodol@dds.nl>, Kyösti Mälkki |
1da177e4 LT |
22 | <kmalkki@cc.hut.fi> and Jean Delvare <khali@linux-fr.org> */ |
23 | ||
24 | #include <linux/kernel.h> | |
25 | #include <linux/module.h> | |
26 | #include <linux/delay.h> | |
1da177e4 LT |
27 | #include <linux/init.h> |
28 | #include <linux/errno.h> | |
29 | #include <linux/sched.h> | |
30 | #include <linux/i2c.h> | |
31 | #include <linux/i2c-algo-bit.h> | |
32 | ||
33 | ||
34 | /* ----- global defines ----------------------------------------------- */ | |
1da177e4 | 35 | |
494dbb64 JD |
36 | #ifdef DEBUG |
37 | #define bit_dbg(level, dev, format, args...) \ | |
38 | do { \ | |
39 | if (i2c_debug >= level) \ | |
40 | dev_dbg(dev, format, ##args); \ | |
41 | } while (0) | |
42 | #else | |
43 | #define bit_dbg(level, dev, format, args...) \ | |
44 | do {} while (0) | |
45 | #endif /* DEBUG */ | |
1da177e4 LT |
46 | |
47 | /* ----- global variables --------------------------------------------- */ | |
48 | ||
1da177e4 | 49 | static int bit_test; /* see if the line-setting functions work */ |
1bddab7f JD |
50 | module_param(bit_test, int, S_IRUGO); |
51 | MODULE_PARM_DESC(bit_test, "lines testing - 0 off; 1 report; 2 fail if stuck"); | |
494dbb64 JD |
52 | |
53 | #ifdef DEBUG | |
54 | static int i2c_debug = 1; | |
55 | module_param(i2c_debug, int, S_IRUGO | S_IWUSR); | |
56 | MODULE_PARM_DESC(i2c_debug, | |
57 | "debug level - 0 off; 1 normal; 2 verbose; 3 very verbose"); | |
58 | #endif | |
1da177e4 LT |
59 | |
60 | /* --- setting states on the bus with the right timing: --------------- */ | |
61 | ||
cf978ab2 DB |
62 | #define setsda(adap, val) adap->setsda(adap->data, val) |
63 | #define setscl(adap, val) adap->setscl(adap->data, val) | |
64 | #define getsda(adap) adap->getsda(adap->data) | |
65 | #define getscl(adap) adap->getscl(adap->data) | |
1da177e4 LT |
66 | |
67 | static inline void sdalo(struct i2c_algo_bit_data *adap) | |
68 | { | |
cf978ab2 | 69 | setsda(adap, 0); |
424ed67c | 70 | udelay((adap->udelay + 1) / 2); |
1da177e4 LT |
71 | } |
72 | ||
73 | static inline void sdahi(struct i2c_algo_bit_data *adap) | |
74 | { | |
cf978ab2 | 75 | setsda(adap, 1); |
424ed67c | 76 | udelay((adap->udelay + 1) / 2); |
1da177e4 LT |
77 | } |
78 | ||
79 | static inline void scllo(struct i2c_algo_bit_data *adap) | |
80 | { | |
cf978ab2 | 81 | setscl(adap, 0); |
424ed67c | 82 | udelay(adap->udelay / 2); |
1da177e4 LT |
83 | } |
84 | ||
85 | /* | |
86 | * Raise scl line, and do checking for delays. This is necessary for slower | |
87 | * devices. | |
88 | */ | |
7b288a01 | 89 | static int sclhi(struct i2c_algo_bit_data *adap) |
1da177e4 LT |
90 | { |
91 | unsigned long start; | |
92 | ||
cf978ab2 | 93 | setscl(adap, 1); |
1da177e4 LT |
94 | |
95 | /* Not all adapters have scl sense line... */ | |
7b288a01 JD |
96 | if (!adap->getscl) |
97 | goto done; | |
1da177e4 | 98 | |
cf978ab2 DB |
99 | start = jiffies; |
100 | while (!getscl(adap)) { | |
101 | /* This hw knows how to read the clock line, so we wait | |
102 | * until it actually gets high. This is safer as some | |
103 | * chips may hold it low ("clock stretching") while they | |
104 | * are processing data internally. | |
105 | */ | |
8ee161ce VS |
106 | if (time_after(jiffies, start + adap->timeout)) { |
107 | /* Test one last time, as we may have been preempted | |
108 | * between last check and timeout test. | |
109 | */ | |
110 | if (getscl(adap)) | |
111 | break; | |
1da177e4 | 112 | return -ETIMEDOUT; |
8ee161ce | 113 | } |
1da177e4 LT |
114 | cond_resched(); |
115 | } | |
494dbb64 JD |
116 | #ifdef DEBUG |
117 | if (jiffies != start && i2c_debug >= 3) | |
118 | pr_debug("i2c-algo-bit: needed %ld jiffies for SCL to go " | |
119 | "high\n", jiffies - start); | |
120 | #endif | |
7b288a01 JD |
121 | |
122 | done: | |
1da177e4 LT |
123 | udelay(adap->udelay); |
124 | return 0; | |
cf978ab2 | 125 | } |
1da177e4 LT |
126 | |
127 | ||
128 | /* --- other auxiliary functions -------------------------------------- */ | |
cf978ab2 | 129 | static void i2c_start(struct i2c_algo_bit_data *adap) |
1da177e4 LT |
130 | { |
131 | /* assert: scl, sda are high */ | |
424ed67c JD |
132 | setsda(adap, 0); |
133 | udelay(adap->udelay); | |
1da177e4 LT |
134 | scllo(adap); |
135 | } | |
136 | ||
cf978ab2 | 137 | static void i2c_repstart(struct i2c_algo_bit_data *adap) |
1da177e4 | 138 | { |
424ed67c | 139 | /* assert: scl is low */ |
424ed67c | 140 | sdahi(adap); |
1da177e4 | 141 | sclhi(adap); |
424ed67c JD |
142 | setsda(adap, 0); |
143 | udelay(adap->udelay); | |
1da177e4 LT |
144 | scllo(adap); |
145 | } | |
146 | ||
147 | ||
cf978ab2 | 148 | static void i2c_stop(struct i2c_algo_bit_data *adap) |
1da177e4 | 149 | { |
1da177e4 LT |
150 | /* assert: scl is low */ |
151 | sdalo(adap); | |
cf978ab2 | 152 | sclhi(adap); |
424ed67c JD |
153 | setsda(adap, 1); |
154 | udelay(adap->udelay); | |
1da177e4 LT |
155 | } |
156 | ||
157 | ||
158 | ||
cf978ab2 | 159 | /* send a byte without start cond., look for arbitration, |
1da177e4 LT |
160 | check ackn. from slave */ |
161 | /* returns: | |
162 | * 1 if the device acknowledged | |
163 | * 0 if the device did not ack | |
164 | * -ETIMEDOUT if an error occurred (while raising the scl line) | |
165 | */ | |
494dbb64 | 166 | static int i2c_outb(struct i2c_adapter *i2c_adap, unsigned char c) |
1da177e4 LT |
167 | { |
168 | int i; | |
169 | int sb; | |
170 | int ack; | |
171 | struct i2c_algo_bit_data *adap = i2c_adap->algo_data; | |
172 | ||
173 | /* assert: scl is low */ | |
cf978ab2 | 174 | for (i = 7; i >= 0; i--) { |
494dbb64 | 175 | sb = (c >> i) & 1; |
cf978ab2 | 176 | setsda(adap, sb); |
424ed67c | 177 | udelay((adap->udelay + 1) / 2); |
cf978ab2 | 178 | if (sclhi(adap) < 0) { /* timed out */ |
494dbb64 JD |
179 | bit_dbg(1, &i2c_adap->dev, "i2c_outb: 0x%02x, " |
180 | "timeout at bit #%d\n", (int)c, i); | |
1da177e4 | 181 | return -ETIMEDOUT; |
cf978ab2 DB |
182 | } |
183 | /* FIXME do arbitration here: | |
184 | * if (sb && !getsda(adap)) -> ouch! Get out of here. | |
185 | * | |
186 | * Report a unique code, so higher level code can retry | |
187 | * the whole (combined) message and *NOT* issue STOP. | |
1da177e4 | 188 | */ |
424ed67c | 189 | scllo(adap); |
1da177e4 LT |
190 | } |
191 | sdahi(adap); | |
cf978ab2 | 192 | if (sclhi(adap) < 0) { /* timeout */ |
494dbb64 JD |
193 | bit_dbg(1, &i2c_adap->dev, "i2c_outb: 0x%02x, " |
194 | "timeout at ack\n", (int)c); | |
195 | return -ETIMEDOUT; | |
cf978ab2 DB |
196 | } |
197 | ||
198 | /* read ack: SDA should be pulled down by slave, or it may | |
199 | * NAK (usually to report problems with the data we wrote). | |
200 | */ | |
494dbb64 JD |
201 | ack = !getsda(adap); /* ack: sda is pulled low -> success */ |
202 | bit_dbg(2, &i2c_adap->dev, "i2c_outb: 0x%02x %s\n", (int)c, | |
203 | ack ? "A" : "NA"); | |
1da177e4 | 204 | |
1da177e4 | 205 | scllo(adap); |
494dbb64 | 206 | return ack; |
1da177e4 LT |
207 | /* assert: scl is low (sda undef) */ |
208 | } | |
209 | ||
210 | ||
cf978ab2 | 211 | static int i2c_inb(struct i2c_adapter *i2c_adap) |
1da177e4 LT |
212 | { |
213 | /* read byte via i2c port, without start/stop sequence */ | |
214 | /* acknowledge is sent in i2c_read. */ | |
215 | int i; | |
cf978ab2 | 216 | unsigned char indata = 0; |
1da177e4 LT |
217 | struct i2c_algo_bit_data *adap = i2c_adap->algo_data; |
218 | ||
219 | /* assert: scl is low */ | |
220 | sdahi(adap); | |
cf978ab2 DB |
221 | for (i = 0; i < 8; i++) { |
222 | if (sclhi(adap) < 0) { /* timeout */ | |
494dbb64 JD |
223 | bit_dbg(1, &i2c_adap->dev, "i2c_inb: timeout at bit " |
224 | "#%d\n", 7 - i); | |
1da177e4 | 225 | return -ETIMEDOUT; |
cf978ab2 | 226 | } |
1da177e4 | 227 | indata *= 2; |
cf978ab2 | 228 | if (getsda(adap)) |
1da177e4 | 229 | indata |= 0x01; |
424ed67c JD |
230 | setscl(adap, 0); |
231 | udelay(i == 7 ? adap->udelay / 2 : adap->udelay); | |
1da177e4 LT |
232 | } |
233 | /* assert: scl is low */ | |
494dbb64 | 234 | return indata; |
1da177e4 LT |
235 | } |
236 | ||
237 | /* | |
238 | * Sanity check for the adapter hardware - check the reaction of | |
239 | * the bus lines only if it seems to be idle. | |
240 | */ | |
d3b3e15d | 241 | static int test_bus(struct i2c_adapter *i2c_adap) |
cf978ab2 | 242 | { |
d3b3e15d AD |
243 | struct i2c_algo_bit_data *adap = i2c_adap->algo_data; |
244 | const char *name = i2c_adap->name; | |
245 | int scl, sda, ret; | |
246 | ||
247 | if (adap->pre_xfer) { | |
248 | ret = adap->pre_xfer(i2c_adap); | |
249 | if (ret < 0) | |
250 | return -ENODEV; | |
251 | } | |
1da177e4 | 252 | |
cf978ab2 | 253 | if (adap->getscl == NULL) |
494dbb64 | 254 | pr_info("%s: Testing SDA only, SCL is not readable\n", name); |
1da177e4 | 255 | |
cf978ab2 DB |
256 | sda = getsda(adap); |
257 | scl = (adap->getscl == NULL) ? 1 : getscl(adap); | |
258 | if (!scl || !sda) { | |
f6beb67d JD |
259 | printk(KERN_WARNING |
260 | "%s: bus seems to be busy (scl=%d, sda=%d)\n", | |
261 | name, scl, sda); | |
1da177e4 LT |
262 | goto bailout; |
263 | } | |
264 | ||
265 | sdalo(adap); | |
cf978ab2 DB |
266 | sda = getsda(adap); |
267 | scl = (adap->getscl == NULL) ? 1 : getscl(adap); | |
268 | if (sda) { | |
494dbb64 | 269 | printk(KERN_WARNING "%s: SDA stuck high!\n", name); |
1da177e4 LT |
270 | goto bailout; |
271 | } | |
cf978ab2 | 272 | if (!scl) { |
494dbb64 JD |
273 | printk(KERN_WARNING "%s: SCL unexpected low " |
274 | "while pulling SDA low!\n", name); | |
1da177e4 | 275 | goto bailout; |
cf978ab2 | 276 | } |
1da177e4 LT |
277 | |
278 | sdahi(adap); | |
cf978ab2 DB |
279 | sda = getsda(adap); |
280 | scl = (adap->getscl == NULL) ? 1 : getscl(adap); | |
281 | if (!sda) { | |
494dbb64 | 282 | printk(KERN_WARNING "%s: SDA stuck low!\n", name); |
1da177e4 LT |
283 | goto bailout; |
284 | } | |
cf978ab2 | 285 | if (!scl) { |
494dbb64 JD |
286 | printk(KERN_WARNING "%s: SCL unexpected low " |
287 | "while pulling SDA high!\n", name); | |
1da177e4 LT |
288 | goto bailout; |
289 | } | |
290 | ||
291 | scllo(adap); | |
cf978ab2 DB |
292 | sda = getsda(adap); |
293 | scl = (adap->getscl == NULL) ? 0 : getscl(adap); | |
294 | if (scl) { | |
494dbb64 | 295 | printk(KERN_WARNING "%s: SCL stuck high!\n", name); |
1da177e4 LT |
296 | goto bailout; |
297 | } | |
cf978ab2 | 298 | if (!sda) { |
494dbb64 JD |
299 | printk(KERN_WARNING "%s: SDA unexpected low " |
300 | "while pulling SCL low!\n", name); | |
1da177e4 LT |
301 | goto bailout; |
302 | } | |
cf978ab2 | 303 | |
1da177e4 | 304 | sclhi(adap); |
cf978ab2 DB |
305 | sda = getsda(adap); |
306 | scl = (adap->getscl == NULL) ? 1 : getscl(adap); | |
307 | if (!scl) { | |
494dbb64 | 308 | printk(KERN_WARNING "%s: SCL stuck low!\n", name); |
1da177e4 LT |
309 | goto bailout; |
310 | } | |
cf978ab2 | 311 | if (!sda) { |
494dbb64 JD |
312 | printk(KERN_WARNING "%s: SDA unexpected low " |
313 | "while pulling SCL high!\n", name); | |
1da177e4 LT |
314 | goto bailout; |
315 | } | |
d3b3e15d AD |
316 | |
317 | if (adap->post_xfer) | |
318 | adap->post_xfer(i2c_adap); | |
319 | ||
494dbb64 | 320 | pr_info("%s: Test OK\n", name); |
1da177e4 LT |
321 | return 0; |
322 | bailout: | |
323 | sdahi(adap); | |
324 | sclhi(adap); | |
d3b3e15d AD |
325 | |
326 | if (adap->post_xfer) | |
327 | adap->post_xfer(i2c_adap); | |
328 | ||
1da177e4 LT |
329 | return -ENODEV; |
330 | } | |
331 | ||
332 | /* ----- Utility functions | |
333 | */ | |
334 | ||
335 | /* try_address tries to contact a chip for a number of | |
336 | * times before it gives up. | |
337 | * return values: | |
338 | * 1 chip answered | |
339 | * 0 chip did not answer | |
340 | * -x transmission error | |
341 | */ | |
7b288a01 | 342 | static int try_address(struct i2c_adapter *i2c_adap, |
1da177e4 LT |
343 | unsigned char addr, int retries) |
344 | { | |
345 | struct i2c_algo_bit_data *adap = i2c_adap->algo_data; | |
97140342 | 346 | int i, ret = 0; |
cf978ab2 DB |
347 | |
348 | for (i = 0; i <= retries; i++) { | |
349 | ret = i2c_outb(i2c_adap, addr); | |
1ecac07a JD |
350 | if (ret == 1 || i == retries) |
351 | break; | |
494dbb64 | 352 | bit_dbg(3, &i2c_adap->dev, "emitting stop condition\n"); |
1da177e4 | 353 | i2c_stop(adap); |
1da177e4 | 354 | udelay(adap->udelay); |
424ed67c | 355 | yield(); |
494dbb64 | 356 | bit_dbg(3, &i2c_adap->dev, "emitting start condition\n"); |
424ed67c | 357 | i2c_start(adap); |
1da177e4 | 358 | } |
494dbb64 JD |
359 | if (i && ret) |
360 | bit_dbg(1, &i2c_adap->dev, "Used %d tries to %s client at " | |
361 | "0x%02x: %s\n", i + 1, | |
362 | addr & 1 ? "read from" : "write to", addr >> 1, | |
363 | ret == 1 ? "success" : "failed, timeout?"); | |
1da177e4 LT |
364 | return ret; |
365 | } | |
366 | ||
367 | static int sendbytes(struct i2c_adapter *i2c_adap, struct i2c_msg *msg) | |
368 | { | |
494dbb64 | 369 | const unsigned char *temp = msg->buf; |
1da177e4 | 370 | int count = msg->len; |
cf978ab2 | 371 | unsigned short nak_ok = msg->flags & I2C_M_IGNORE_NAK; |
1da177e4 | 372 | int retval; |
cf978ab2 | 373 | int wrcount = 0; |
1da177e4 LT |
374 | |
375 | while (count > 0) { | |
494dbb64 | 376 | retval = i2c_outb(i2c_adap, *temp); |
cf978ab2 DB |
377 | |
378 | /* OK/ACK; or ignored NAK */ | |
379 | if ((retval > 0) || (nak_ok && (retval == 0))) { | |
380 | count--; | |
1da177e4 LT |
381 | temp++; |
382 | wrcount++; | |
bf3e2d1d DB |
383 | |
384 | /* A slave NAKing the master means the slave didn't like | |
385 | * something about the data it saw. For example, maybe | |
386 | * the SMBus PEC was wrong. | |
387 | */ | |
388 | } else if (retval == 0) { | |
389 | dev_err(&i2c_adap->dev, "sendbytes: NAK bailout.\n"); | |
390 | return -EIO; | |
391 | ||
392 | /* Timeout; or (someday) lost arbitration | |
393 | * | |
394 | * FIXME Lost ARB implies retrying the transaction from | |
395 | * the first message, after the "winning" master issues | |
396 | * its STOP. As a rule, upper layer code has no reason | |
397 | * to know or care about this ... it is *NOT* an error. | |
398 | */ | |
399 | } else { | |
400 | dev_err(&i2c_adap->dev, "sendbytes: error %d\n", | |
401 | retval); | |
402 | return retval; | |
1da177e4 | 403 | } |
1da177e4 LT |
404 | } |
405 | return wrcount; | |
406 | } | |
407 | ||
939bc494 DB |
408 | static int acknak(struct i2c_adapter *i2c_adap, int is_ack) |
409 | { | |
410 | struct i2c_algo_bit_data *adap = i2c_adap->algo_data; | |
411 | ||
412 | /* assert: sda is high */ | |
413 | if (is_ack) /* send ack */ | |
414 | setsda(adap, 0); | |
415 | udelay((adap->udelay + 1) / 2); | |
416 | if (sclhi(adap) < 0) { /* timeout */ | |
417 | dev_err(&i2c_adap->dev, "readbytes: ack/nak timeout\n"); | |
418 | return -ETIMEDOUT; | |
419 | } | |
420 | scllo(adap); | |
421 | return 0; | |
422 | } | |
423 | ||
7b288a01 | 424 | static int readbytes(struct i2c_adapter *i2c_adap, struct i2c_msg *msg) |
1da177e4 LT |
425 | { |
426 | int inval; | |
cf978ab2 | 427 | int rdcount = 0; /* counts bytes read */ |
494dbb64 | 428 | unsigned char *temp = msg->buf; |
1da177e4 | 429 | int count = msg->len; |
939bc494 | 430 | const unsigned flags = msg->flags; |
1da177e4 LT |
431 | |
432 | while (count > 0) { | |
433 | inval = i2c_inb(i2c_adap); | |
cf978ab2 | 434 | if (inval >= 0) { |
1da177e4 LT |
435 | *temp = inval; |
436 | rdcount++; | |
437 | } else { /* read timed out */ | |
1da177e4 LT |
438 | break; |
439 | } | |
440 | ||
441 | temp++; | |
442 | count--; | |
443 | ||
3c4bb241 JD |
444 | /* Some SMBus transactions require that we receive the |
445 | transaction length as the first read byte. */ | |
939bc494 | 446 | if (rdcount == 1 && (flags & I2C_M_RECV_LEN)) { |
3c4bb241 | 447 | if (inval <= 0 || inval > I2C_SMBUS_BLOCK_MAX) { |
939bc494 DB |
448 | if (!(flags & I2C_M_NO_RD_ACK)) |
449 | acknak(i2c_adap, 0); | |
494dbb64 JD |
450 | dev_err(&i2c_adap->dev, "readbytes: invalid " |
451 | "block length (%d)\n", inval); | |
abc01b27 | 452 | return -EPROTO; |
3c4bb241 JD |
453 | } |
454 | /* The original count value accounts for the extra | |
455 | bytes, that is, either 1 for a regular transaction, | |
456 | or 2 for a PEC transaction. */ | |
457 | count += inval; | |
458 | msg->len += inval; | |
459 | } | |
939bc494 DB |
460 | |
461 | bit_dbg(2, &i2c_adap->dev, "readbytes: 0x%02x %s\n", | |
462 | inval, | |
463 | (flags & I2C_M_NO_RD_ACK) | |
464 | ? "(no ack/nak)" | |
465 | : (count ? "A" : "NA")); | |
466 | ||
467 | if (!(flags & I2C_M_NO_RD_ACK)) { | |
468 | inval = acknak(i2c_adap, count); | |
469 | if (inval < 0) | |
470 | return inval; | |
471 | } | |
1da177e4 LT |
472 | } |
473 | return rdcount; | |
474 | } | |
475 | ||
476 | /* doAddress initiates the transfer by generating the start condition (in | |
477 | * try_address) and transmits the address in the necessary format to handle | |
478 | * reads, writes as well as 10bit-addresses. | |
479 | * returns: | |
480 | * 0 everything went okay, the chip ack'ed, or IGNORE_NAK flag was set | |
abc01b27 | 481 | * -x an error occurred (like: -ENXIO if the device did not answer, or |
cf978ab2 | 482 | * -ETIMEDOUT, for example if the lines are stuck...) |
1da177e4 | 483 | */ |
7b288a01 | 484 | static int bit_doAddress(struct i2c_adapter *i2c_adap, struct i2c_msg *msg) |
1da177e4 LT |
485 | { |
486 | unsigned short flags = msg->flags; | |
487 | unsigned short nak_ok = msg->flags & I2C_M_IGNORE_NAK; | |
488 | struct i2c_algo_bit_data *adap = i2c_adap->algo_data; | |
489 | ||
490 | unsigned char addr; | |
491 | int ret, retries; | |
492 | ||
493 | retries = nak_ok ? 0 : i2c_adap->retries; | |
cf978ab2 DB |
494 | |
495 | if (flags & I2C_M_TEN) { | |
1da177e4 | 496 | /* a ten bit address */ |
cc6bcf7d | 497 | addr = 0xf0 | ((msg->addr >> 7) & 0x06); |
494dbb64 | 498 | bit_dbg(2, &i2c_adap->dev, "addr0: %d\n", addr); |
1da177e4 LT |
499 | /* try extended address code...*/ |
500 | ret = try_address(i2c_adap, addr, retries); | |
501 | if ((ret != 1) && !nak_ok) { | |
494dbb64 JD |
502 | dev_err(&i2c_adap->dev, |
503 | "died at extended address code\n"); | |
abc01b27 | 504 | return -ENXIO; |
1da177e4 LT |
505 | } |
506 | /* the remaining 8 bit address */ | |
cc6bcf7d | 507 | ret = i2c_outb(i2c_adap, msg->addr & 0xff); |
1da177e4 LT |
508 | if ((ret != 1) && !nak_ok) { |
509 | /* the chip did not ack / xmission error occurred */ | |
494dbb64 | 510 | dev_err(&i2c_adap->dev, "died at 2nd address code\n"); |
abc01b27 | 511 | return -ENXIO; |
1da177e4 | 512 | } |
cf978ab2 | 513 | if (flags & I2C_M_RD) { |
494dbb64 JD |
514 | bit_dbg(3, &i2c_adap->dev, "emitting repeated " |
515 | "start condition\n"); | |
1da177e4 LT |
516 | i2c_repstart(adap); |
517 | /* okay, now switch into reading mode */ | |
518 | addr |= 0x01; | |
519 | ret = try_address(i2c_adap, addr, retries); | |
cf978ab2 | 520 | if ((ret != 1) && !nak_ok) { |
494dbb64 JD |
521 | dev_err(&i2c_adap->dev, |
522 | "died at repeated address code\n"); | |
abc01b27 | 523 | return -EIO; |
1da177e4 LT |
524 | } |
525 | } | |
526 | } else { /* normal 7bit address */ | |
cf978ab2 DB |
527 | addr = msg->addr << 1; |
528 | if (flags & I2C_M_RD) | |
1da177e4 | 529 | addr |= 1; |
cf978ab2 | 530 | if (flags & I2C_M_REV_DIR_ADDR) |
1da177e4 LT |
531 | addr ^= 1; |
532 | ret = try_address(i2c_adap, addr, retries); | |
cf978ab2 | 533 | if ((ret != 1) && !nak_ok) |
97140342 | 534 | return -ENXIO; |
1da177e4 LT |
535 | } |
536 | ||
537 | return 0; | |
538 | } | |
539 | ||
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; | |
cf978ab2 | 545 | int i, ret; |
1da177e4 LT |
546 | unsigned short nak_ok; |
547 | ||
0a9c1475 JD |
548 | if (adap->pre_xfer) { |
549 | ret = adap->pre_xfer(i2c_adap); | |
550 | if (ret < 0) | |
551 | return ret; | |
552 | } | |
553 | ||
494dbb64 | 554 | bit_dbg(3, &i2c_adap->dev, "emitting start condition\n"); |
1da177e4 | 555 | i2c_start(adap); |
cf978ab2 | 556 | for (i = 0; i < num; i++) { |
1da177e4 | 557 | pmsg = &msgs[i]; |
cf978ab2 | 558 | nak_ok = pmsg->flags & I2C_M_IGNORE_NAK; |
1da177e4 LT |
559 | if (!(pmsg->flags & I2C_M_NOSTART)) { |
560 | if (i) { | |
494dbb64 JD |
561 | bit_dbg(3, &i2c_adap->dev, "emitting " |
562 | "repeated start condition\n"); | |
1da177e4 LT |
563 | i2c_repstart(adap); |
564 | } | |
565 | ret = bit_doAddress(i2c_adap, pmsg); | |
566 | if ((ret != 0) && !nak_ok) { | |
494dbb64 JD |
567 | bit_dbg(1, &i2c_adap->dev, "NAK from " |
568 | "device addr 0x%02x msg #%d\n", | |
569 | msgs[i].addr, i); | |
1ecac07a | 570 | goto bailout; |
1da177e4 LT |
571 | } |
572 | } | |
cf978ab2 | 573 | if (pmsg->flags & I2C_M_RD) { |
1da177e4 LT |
574 | /* read bytes into buffer*/ |
575 | ret = readbytes(i2c_adap, pmsg); | |
494dbb64 JD |
576 | if (ret >= 1) |
577 | bit_dbg(2, &i2c_adap->dev, "read %d byte%s\n", | |
578 | ret, ret == 1 ? "" : "s"); | |
1ecac07a JD |
579 | if (ret < pmsg->len) { |
580 | if (ret >= 0) | |
abc01b27 | 581 | ret = -EIO; |
1ecac07a | 582 | goto bailout; |
1da177e4 LT |
583 | } |
584 | } else { | |
585 | /* write bytes from buffer */ | |
586 | ret = sendbytes(i2c_adap, pmsg); | |
494dbb64 JD |
587 | if (ret >= 1) |
588 | bit_dbg(2, &i2c_adap->dev, "wrote %d byte%s\n", | |
589 | ret, ret == 1 ? "" : "s"); | |
1ecac07a JD |
590 | if (ret < pmsg->len) { |
591 | if (ret >= 0) | |
abc01b27 | 592 | ret = -EIO; |
1ecac07a | 593 | goto bailout; |
1da177e4 LT |
594 | } |
595 | } | |
596 | } | |
1ecac07a JD |
597 | ret = i; |
598 | ||
599 | bailout: | |
494dbb64 | 600 | bit_dbg(3, &i2c_adap->dev, "emitting stop condition\n"); |
1da177e4 | 601 | i2c_stop(adap); |
0a9c1475 JD |
602 | |
603 | if (adap->post_xfer) | |
604 | adap->post_xfer(i2c_adap); | |
1ecac07a | 605 | return ret; |
1da177e4 LT |
606 | } |
607 | ||
608 | static u32 bit_func(struct i2c_adapter *adap) | |
609 | { | |
cf978ab2 | 610 | return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | |
3c4bb241 JD |
611 | I2C_FUNC_SMBUS_READ_BLOCK_DATA | |
612 | I2C_FUNC_SMBUS_BLOCK_PROC_CALL | | |
1da177e4 LT |
613 | I2C_FUNC_10BIT_ADDR | I2C_FUNC_PROTOCOL_MANGLING; |
614 | } | |
615 | ||
616 | ||
617 | /* -----exported algorithm data: ------------------------------------- */ | |
618 | ||
9e11a9fb | 619 | static const struct i2c_algorithm i2c_bit_algo = { |
1da177e4 LT |
620 | .master_xfer = bit_xfer, |
621 | .functionality = bit_func, | |
622 | }; | |
623 | ||
cf978ab2 DB |
624 | /* |
625 | * registering functions to load algorithms at runtime | |
1da177e4 | 626 | */ |
f451171c JD |
627 | static int __i2c_bit_add_bus(struct i2c_adapter *adap, |
628 | int (*add_adapter)(struct i2c_adapter *)) | |
1da177e4 LT |
629 | { |
630 | struct i2c_algo_bit_data *bit_adap = adap->algo_data; | |
af5a60ba | 631 | int ret; |
1da177e4 LT |
632 | |
633 | if (bit_test) { | |
d3b3e15d | 634 | ret = test_bus(adap); |
1bddab7f | 635 | if (bit_test >= 2 && ret < 0) |
1da177e4 LT |
636 | return -ENODEV; |
637 | } | |
638 | ||
1da177e4 | 639 | /* register new adapter to i2c module... */ |
1da177e4 | 640 | adap->algo = &i2c_bit_algo; |
8fcfef6e | 641 | adap->retries = 3; |
1da177e4 | 642 | |
af5a60ba JD |
643 | ret = add_adapter(adap); |
644 | if (ret < 0) | |
645 | return ret; | |
646 | ||
647 | /* Complain if SCL can't be read */ | |
648 | if (bit_adap->getscl == NULL) { | |
649 | dev_warn(&adap->dev, "Not I2C compliant: can't read SCL\n"); | |
650 | dev_warn(&adap->dev, "Bus may be unreliable\n"); | |
651 | } | |
652 | return 0; | |
0f3b4838 JD |
653 | } |
654 | ||
655 | int i2c_bit_add_bus(struct i2c_adapter *adap) | |
656 | { | |
f451171c | 657 | return __i2c_bit_add_bus(adap, i2c_add_adapter); |
1da177e4 | 658 | } |
1da177e4 | 659 | EXPORT_SYMBOL(i2c_bit_add_bus); |
1da177e4 | 660 | |
0f3b4838 JD |
661 | int i2c_bit_add_numbered_bus(struct i2c_adapter *adap) |
662 | { | |
f451171c | 663 | return __i2c_bit_add_bus(adap, i2c_add_numbered_adapter); |
0f3b4838 JD |
664 | } |
665 | EXPORT_SYMBOL(i2c_bit_add_numbered_bus); | |
666 | ||
1da177e4 LT |
667 | MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>"); |
668 | MODULE_DESCRIPTION("I2C-Bus bit-banging algorithm"); | |
669 | MODULE_LICENSE("GPL"); |