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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. | |
cf978ab2 | 15 | * ------------------------------------------------------------------------- */ |
1da177e4 | 16 | |
96de0e25 | 17 | /* With some changes from Frodo Looijaard <frodol@dds.nl>, Kyösti Mälkki |
7c81c60f | 18 | <kmalkki@cc.hut.fi> and Jean Delvare <jdelvare@suse.de> */ |
1da177e4 LT |
19 | |
20 | #include <linux/kernel.h> | |
21 | #include <linux/module.h> | |
22 | #include <linux/delay.h> | |
1da177e4 LT |
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 ----------------------------------------------- */ | |
1da177e4 | 30 | |
494dbb64 JD |
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 */ | |
1da177e4 LT |
41 | |
42 | /* ----- global variables --------------------------------------------- */ | |
43 | ||
1da177e4 | 44 | static int bit_test; /* see if the line-setting functions work */ |
1bddab7f JD |
45 | module_param(bit_test, int, S_IRUGO); |
46 | MODULE_PARM_DESC(bit_test, "lines testing - 0 off; 1 report; 2 fail if stuck"); | |
494dbb64 JD |
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 | |
1da177e4 LT |
54 | |
55 | /* --- setting states on the bus with the right timing: --------------- */ | |
56 | ||
cf978ab2 DB |
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) | |
1da177e4 LT |
61 | |
62 | static inline void sdalo(struct i2c_algo_bit_data *adap) | |
63 | { | |
cf978ab2 | 64 | setsda(adap, 0); |
424ed67c | 65 | udelay((adap->udelay + 1) / 2); |
1da177e4 LT |
66 | } |
67 | ||
68 | static inline void sdahi(struct i2c_algo_bit_data *adap) | |
69 | { | |
cf978ab2 | 70 | setsda(adap, 1); |
424ed67c | 71 | udelay((adap->udelay + 1) / 2); |
1da177e4 LT |
72 | } |
73 | ||
74 | static inline void scllo(struct i2c_algo_bit_data *adap) | |
75 | { | |
cf978ab2 | 76 | setscl(adap, 0); |
424ed67c | 77 | udelay(adap->udelay / 2); |
1da177e4 LT |
78 | } |
79 | ||
80 | /* | |
81 | * Raise scl line, and do checking for delays. This is necessary for slower | |
82 | * devices. | |
83 | */ | |
7b288a01 | 84 | static int sclhi(struct i2c_algo_bit_data *adap) |
1da177e4 LT |
85 | { |
86 | unsigned long start; | |
87 | ||
cf978ab2 | 88 | setscl(adap, 1); |
1da177e4 LT |
89 | |
90 | /* Not all adapters have scl sense line... */ | |
7b288a01 JD |
91 | if (!adap->getscl) |
92 | goto done; | |
1da177e4 | 93 | |
cf978ab2 DB |
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 | */ | |
8ee161ce VS |
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; | |
1da177e4 | 107 | return -ETIMEDOUT; |
8ee161ce | 108 | } |
41101a33 | 109 | cpu_relax(); |
1da177e4 | 110 | } |
494dbb64 JD |
111 | #ifdef DEBUG |
112 | if (jiffies != start && i2c_debug >= 3) | |
1204d12a JK |
113 | pr_debug("i2c-algo-bit: needed %ld jiffies for SCL to go high\n", |
114 | jiffies - start); | |
494dbb64 | 115 | #endif |
7b288a01 JD |
116 | |
117 | done: | |
1da177e4 LT |
118 | udelay(adap->udelay); |
119 | return 0; | |
cf978ab2 | 120 | } |
1da177e4 LT |
121 | |
122 | ||
123 | /* --- other auxiliary functions -------------------------------------- */ | |
cf978ab2 | 124 | static void i2c_start(struct i2c_algo_bit_data *adap) |
1da177e4 LT |
125 | { |
126 | /* assert: scl, sda are high */ | |
424ed67c JD |
127 | setsda(adap, 0); |
128 | udelay(adap->udelay); | |
1da177e4 LT |
129 | scllo(adap); |
130 | } | |
131 | ||
cf978ab2 | 132 | static void i2c_repstart(struct i2c_algo_bit_data *adap) |
1da177e4 | 133 | { |
424ed67c | 134 | /* assert: scl is low */ |
424ed67c | 135 | sdahi(adap); |
1da177e4 | 136 | sclhi(adap); |
424ed67c JD |
137 | setsda(adap, 0); |
138 | udelay(adap->udelay); | |
1da177e4 LT |
139 | scllo(adap); |
140 | } | |
141 | ||
142 | ||
cf978ab2 | 143 | static void i2c_stop(struct i2c_algo_bit_data *adap) |
1da177e4 | 144 | { |
1da177e4 LT |
145 | /* assert: scl is low */ |
146 | sdalo(adap); | |
cf978ab2 | 147 | sclhi(adap); |
424ed67c JD |
148 | setsda(adap, 1); |
149 | udelay(adap->udelay); | |
1da177e4 LT |
150 | } |
151 | ||
152 | ||
153 | ||
cf978ab2 | 154 | /* send a byte without start cond., look for arbitration, |
1da177e4 LT |
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 | */ | |
494dbb64 | 161 | static int i2c_outb(struct i2c_adapter *i2c_adap, unsigned char c) |
1da177e4 LT |
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 */ | |
cf978ab2 | 169 | for (i = 7; i >= 0; i--) { |
494dbb64 | 170 | sb = (c >> i) & 1; |
cf978ab2 | 171 | setsda(adap, sb); |
424ed67c | 172 | udelay((adap->udelay + 1) / 2); |
cf978ab2 | 173 | if (sclhi(adap) < 0) { /* timed out */ |
1204d12a JK |
174 | bit_dbg(1, &i2c_adap->dev, |
175 | "i2c_outb: 0x%02x, timeout at bit #%d\n", | |
176 | (int)c, i); | |
1da177e4 | 177 | return -ETIMEDOUT; |
cf978ab2 DB |
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. | |
1da177e4 | 184 | */ |
424ed67c | 185 | scllo(adap); |
1da177e4 LT |
186 | } |
187 | sdahi(adap); | |
cf978ab2 | 188 | if (sclhi(adap) < 0) { /* timeout */ |
1204d12a JK |
189 | bit_dbg(1, &i2c_adap->dev, |
190 | "i2c_outb: 0x%02x, timeout at ack\n", (int)c); | |
494dbb64 | 191 | return -ETIMEDOUT; |
cf978ab2 DB |
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 | */ | |
494dbb64 JD |
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"); | |
1da177e4 | 200 | |
1da177e4 | 201 | scllo(adap); |
494dbb64 | 202 | return ack; |
1da177e4 LT |
203 | /* assert: scl is low (sda undef) */ |
204 | } | |
205 | ||
206 | ||
cf978ab2 | 207 | static int i2c_inb(struct i2c_adapter *i2c_adap) |
1da177e4 LT |
208 | { |
209 | /* read byte via i2c port, without start/stop sequence */ | |
210 | /* acknowledge is sent in i2c_read. */ | |
211 | int i; | |
cf978ab2 | 212 | unsigned char indata = 0; |
1da177e4 LT |
213 | struct i2c_algo_bit_data *adap = i2c_adap->algo_data; |
214 | ||
215 | /* assert: scl is low */ | |
216 | sdahi(adap); | |
cf978ab2 DB |
217 | for (i = 0; i < 8; i++) { |
218 | if (sclhi(adap) < 0) { /* timeout */ | |
1204d12a JK |
219 | bit_dbg(1, &i2c_adap->dev, |
220 | "i2c_inb: timeout at bit #%d\n", | |
221 | 7 - i); | |
1da177e4 | 222 | return -ETIMEDOUT; |
cf978ab2 | 223 | } |
1da177e4 | 224 | indata *= 2; |
cf978ab2 | 225 | if (getsda(adap)) |
1da177e4 | 226 | indata |= 0x01; |
424ed67c JD |
227 | setscl(adap, 0); |
228 | udelay(i == 7 ? adap->udelay / 2 : adap->udelay); | |
1da177e4 LT |
229 | } |
230 | /* assert: scl is low */ | |
494dbb64 | 231 | return indata; |
1da177e4 LT |
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 | */ | |
d3b3e15d | 238 | static int test_bus(struct i2c_adapter *i2c_adap) |
cf978ab2 | 239 | { |
d3b3e15d AD |
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 | } | |
1da177e4 | 249 | |
cf978ab2 | 250 | if (adap->getscl == NULL) |
494dbb64 | 251 | pr_info("%s: Testing SDA only, SCL is not readable\n", name); |
1da177e4 | 252 | |
cf978ab2 DB |
253 | sda = getsda(adap); |
254 | scl = (adap->getscl == NULL) ? 1 : getscl(adap); | |
255 | if (!scl || !sda) { | |
f6beb67d JD |
256 | printk(KERN_WARNING |
257 | "%s: bus seems to be busy (scl=%d, sda=%d)\n", | |
258 | name, scl, sda); | |
1da177e4 LT |
259 | goto bailout; |
260 | } | |
261 | ||
262 | sdalo(adap); | |
cf978ab2 DB |
263 | sda = getsda(adap); |
264 | scl = (adap->getscl == NULL) ? 1 : getscl(adap); | |
265 | if (sda) { | |
494dbb64 | 266 | printk(KERN_WARNING "%s: SDA stuck high!\n", name); |
1da177e4 LT |
267 | goto bailout; |
268 | } | |
cf978ab2 | 269 | if (!scl) { |
1204d12a JK |
270 | printk(KERN_WARNING |
271 | "%s: SCL unexpected low while pulling SDA low!\n", | |
272 | name); | |
1da177e4 | 273 | goto bailout; |
cf978ab2 | 274 | } |
1da177e4 LT |
275 | |
276 | sdahi(adap); | |
cf978ab2 DB |
277 | sda = getsda(adap); |
278 | scl = (adap->getscl == NULL) ? 1 : getscl(adap); | |
279 | if (!sda) { | |
494dbb64 | 280 | printk(KERN_WARNING "%s: SDA stuck low!\n", name); |
1da177e4 LT |
281 | goto bailout; |
282 | } | |
cf978ab2 | 283 | if (!scl) { |
1204d12a JK |
284 | printk(KERN_WARNING |
285 | "%s: SCL unexpected low while pulling SDA high!\n", | |
286 | name); | |
1da177e4 LT |
287 | goto bailout; |
288 | } | |
289 | ||
290 | scllo(adap); | |
cf978ab2 DB |
291 | sda = getsda(adap); |
292 | scl = (adap->getscl == NULL) ? 0 : getscl(adap); | |
293 | if (scl) { | |
494dbb64 | 294 | printk(KERN_WARNING "%s: SCL stuck high!\n", name); |
1da177e4 LT |
295 | goto bailout; |
296 | } | |
cf978ab2 | 297 | if (!sda) { |
1204d12a JK |
298 | printk(KERN_WARNING |
299 | "%s: SDA unexpected low while pulling SCL low!\n", | |
300 | 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) { |
1204d12a JK |
312 | printk(KERN_WARNING |
313 | "%s: SDA unexpected low while pulling SCL high!\n", | |
314 | name); | |
1da177e4 LT |
315 | goto bailout; |
316 | } | |
d3b3e15d AD |
317 | |
318 | if (adap->post_xfer) | |
319 | adap->post_xfer(i2c_adap); | |
320 | ||
494dbb64 | 321 | pr_info("%s: Test OK\n", name); |
1da177e4 LT |
322 | return 0; |
323 | bailout: | |
324 | sdahi(adap); | |
325 | sclhi(adap); | |
d3b3e15d AD |
326 | |
327 | if (adap->post_xfer) | |
328 | adap->post_xfer(i2c_adap); | |
329 | ||
1da177e4 LT |
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 | */ | |
7b288a01 | 343 | static int try_address(struct i2c_adapter *i2c_adap, |
1da177e4 LT |
344 | unsigned char addr, int retries) |
345 | { | |
346 | struct i2c_algo_bit_data *adap = i2c_adap->algo_data; | |
97140342 | 347 | int i, ret = 0; |
cf978ab2 DB |
348 | |
349 | for (i = 0; i <= retries; i++) { | |
350 | ret = i2c_outb(i2c_adap, addr); | |
1ecac07a JD |
351 | if (ret == 1 || i == retries) |
352 | break; | |
494dbb64 | 353 | bit_dbg(3, &i2c_adap->dev, "emitting stop condition\n"); |
1da177e4 | 354 | i2c_stop(adap); |
1da177e4 | 355 | udelay(adap->udelay); |
424ed67c | 356 | yield(); |
494dbb64 | 357 | bit_dbg(3, &i2c_adap->dev, "emitting start condition\n"); |
424ed67c | 358 | i2c_start(adap); |
1da177e4 | 359 | } |
494dbb64 | 360 | if (i && ret) |
1204d12a JK |
361 | bit_dbg(1, &i2c_adap->dev, |
362 | "Used %d tries to %s client at 0x%02x: %s\n", i + 1, | |
494dbb64 JD |
363 | addr & 1 ? "read from" : "write to", addr >> 1, |
364 | ret == 1 ? "success" : "failed, timeout?"); | |
1da177e4 LT |
365 | return ret; |
366 | } | |
367 | ||
368 | static int sendbytes(struct i2c_adapter *i2c_adap, struct i2c_msg *msg) | |
369 | { | |
494dbb64 | 370 | const unsigned char *temp = msg->buf; |
1da177e4 | 371 | int count = msg->len; |
cf978ab2 | 372 | unsigned short nak_ok = msg->flags & I2C_M_IGNORE_NAK; |
1da177e4 | 373 | int retval; |
cf978ab2 | 374 | int wrcount = 0; |
1da177e4 LT |
375 | |
376 | while (count > 0) { | |
494dbb64 | 377 | retval = i2c_outb(i2c_adap, *temp); |
cf978ab2 DB |
378 | |
379 | /* OK/ACK; or ignored NAK */ | |
380 | if ((retval > 0) || (nak_ok && (retval == 0))) { | |
381 | count--; | |
1da177e4 LT |
382 | temp++; |
383 | wrcount++; | |
bf3e2d1d DB |
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; | |
1da177e4 | 404 | } |
1da177e4 LT |
405 | } |
406 | return wrcount; | |
407 | } | |
408 | ||
939bc494 DB |
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 | ||
7b288a01 | 425 | static int readbytes(struct i2c_adapter *i2c_adap, struct i2c_msg *msg) |
1da177e4 LT |
426 | { |
427 | int inval; | |
cf978ab2 | 428 | int rdcount = 0; /* counts bytes read */ |
494dbb64 | 429 | unsigned char *temp = msg->buf; |
1da177e4 | 430 | int count = msg->len; |
939bc494 | 431 | const unsigned flags = msg->flags; |
1da177e4 LT |
432 | |
433 | while (count > 0) { | |
434 | inval = i2c_inb(i2c_adap); | |
cf978ab2 | 435 | if (inval >= 0) { |
1da177e4 LT |
436 | *temp = inval; |
437 | rdcount++; | |
438 | } else { /* read timed out */ | |
1da177e4 LT |
439 | break; |
440 | } | |
441 | ||
442 | temp++; | |
443 | count--; | |
444 | ||
3c4bb241 JD |
445 | /* Some SMBus transactions require that we receive the |
446 | transaction length as the first read byte. */ | |
939bc494 | 447 | if (rdcount == 1 && (flags & I2C_M_RECV_LEN)) { |
3c4bb241 | 448 | if (inval <= 0 || inval > I2C_SMBUS_BLOCK_MAX) { |
939bc494 DB |
449 | if (!(flags & I2C_M_NO_RD_ACK)) |
450 | acknak(i2c_adap, 0); | |
1204d12a JK |
451 | dev_err(&i2c_adap->dev, |
452 | "readbytes: invalid block length (%d)\n", | |
453 | inval); | |
abc01b27 | 454 | return -EPROTO; |
3c4bb241 JD |
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 | } | |
939bc494 DB |
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 | } | |
1da177e4 LT |
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 | |
abc01b27 | 483 | * -x an error occurred (like: -ENXIO if the device did not answer, or |
cf978ab2 | 484 | * -ETIMEDOUT, for example if the lines are stuck...) |
1da177e4 | 485 | */ |
7b288a01 | 486 | static int bit_doAddress(struct i2c_adapter *i2c_adap, struct i2c_msg *msg) |
1da177e4 LT |
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; | |
cf978ab2 DB |
496 | |
497 | if (flags & I2C_M_TEN) { | |
1da177e4 | 498 | /* a ten bit address */ |
cc6bcf7d | 499 | addr = 0xf0 | ((msg->addr >> 7) & 0x06); |
494dbb64 | 500 | bit_dbg(2, &i2c_adap->dev, "addr0: %d\n", addr); |
1da177e4 LT |
501 | /* try extended address code...*/ |
502 | ret = try_address(i2c_adap, addr, retries); | |
503 | if ((ret != 1) && !nak_ok) { | |
494dbb64 JD |
504 | dev_err(&i2c_adap->dev, |
505 | "died at extended address code\n"); | |
abc01b27 | 506 | return -ENXIO; |
1da177e4 LT |
507 | } |
508 | /* the remaining 8 bit address */ | |
cc6bcf7d | 509 | ret = i2c_outb(i2c_adap, msg->addr & 0xff); |
1da177e4 LT |
510 | if ((ret != 1) && !nak_ok) { |
511 | /* the chip did not ack / xmission error occurred */ | |
494dbb64 | 512 | dev_err(&i2c_adap->dev, "died at 2nd address code\n"); |
abc01b27 | 513 | return -ENXIO; |
1da177e4 | 514 | } |
cf978ab2 | 515 | if (flags & I2C_M_RD) { |
1204d12a JK |
516 | bit_dbg(3, &i2c_adap->dev, |
517 | "emitting repeated start condition\n"); | |
1da177e4 LT |
518 | i2c_repstart(adap); |
519 | /* okay, now switch into reading mode */ | |
520 | addr |= 0x01; | |
521 | ret = try_address(i2c_adap, addr, retries); | |
cf978ab2 | 522 | if ((ret != 1) && !nak_ok) { |
494dbb64 JD |
523 | dev_err(&i2c_adap->dev, |
524 | "died at repeated address code\n"); | |
abc01b27 | 525 | return -EIO; |
1da177e4 LT |
526 | } |
527 | } | |
528 | } else { /* normal 7bit address */ | |
ac6d5298 | 529 | addr = i2c_8bit_addr_from_msg(msg); |
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) { | |
606fd278 JD |
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 | } | |
1da177e4 LT |
571 | } |
572 | ret = bit_doAddress(i2c_adap, pmsg); | |
573 | if ((ret != 0) && !nak_ok) { | |
1204d12a JK |
574 | bit_dbg(1, &i2c_adap->dev, |
575 | "NAK from device addr 0x%02x msg #%d\n", | |
494dbb64 | 576 | msgs[i].addr, i); |
1ecac07a | 577 | goto bailout; |
1da177e4 LT |
578 | } |
579 | } | |
cf978ab2 | 580 | if (pmsg->flags & I2C_M_RD) { |
1da177e4 LT |
581 | /* read bytes into buffer*/ |
582 | ret = readbytes(i2c_adap, pmsg); | |
494dbb64 JD |
583 | if (ret >= 1) |
584 | bit_dbg(2, &i2c_adap->dev, "read %d byte%s\n", | |
585 | ret, ret == 1 ? "" : "s"); | |
1ecac07a JD |
586 | if (ret < pmsg->len) { |
587 | if (ret >= 0) | |
abc01b27 | 588 | ret = -EIO; |
1ecac07a | 589 | goto bailout; |
1da177e4 LT |
590 | } |
591 | } else { | |
592 | /* write bytes from buffer */ | |
593 | ret = sendbytes(i2c_adap, pmsg); | |
494dbb64 JD |
594 | if (ret >= 1) |
595 | bit_dbg(2, &i2c_adap->dev, "wrote %d byte%s\n", | |
596 | ret, ret == 1 ? "" : "s"); | |
1ecac07a JD |
597 | if (ret < pmsg->len) { |
598 | if (ret >= 0) | |
abc01b27 | 599 | ret = -EIO; |
1ecac07a | 600 | goto bailout; |
1da177e4 LT |
601 | } |
602 | } | |
603 | } | |
1ecac07a JD |
604 | ret = i; |
605 | ||
606 | bailout: | |
494dbb64 | 607 | bit_dbg(3, &i2c_adap->dev, "emitting stop condition\n"); |
1da177e4 | 608 | i2c_stop(adap); |
0a9c1475 JD |
609 | |
610 | if (adap->post_xfer) | |
611 | adap->post_xfer(i2c_adap); | |
1ecac07a | 612 | return ret; |
1da177e4 LT |
613 | } |
614 | ||
615 | static u32 bit_func(struct i2c_adapter *adap) | |
616 | { | |
14674e70 | 617 | return I2C_FUNC_I2C | I2C_FUNC_NOSTART | I2C_FUNC_SMBUS_EMUL | |
3c4bb241 JD |
618 | I2C_FUNC_SMBUS_READ_BLOCK_DATA | |
619 | I2C_FUNC_SMBUS_BLOCK_PROC_CALL | | |
1da177e4 LT |
620 | I2C_FUNC_10BIT_ADDR | I2C_FUNC_PROTOCOL_MANGLING; |
621 | } | |
622 | ||
623 | ||
624 | /* -----exported algorithm data: ------------------------------------- */ | |
625 | ||
b0209b39 | 626 | const struct i2c_algorithm i2c_bit_algo = { |
1da177e4 LT |
627 | .master_xfer = bit_xfer, |
628 | .functionality = bit_func, | |
629 | }; | |
b0209b39 | 630 | EXPORT_SYMBOL(i2c_bit_algo); |
1da177e4 | 631 | |
ef51d3ff | 632 | static const struct i2c_adapter_quirks i2c_bit_quirk_no_clk_stretch = { |
a94d306b NC |
633 | .flags = I2C_AQ_NO_CLK_STRETCH, |
634 | }; | |
635 | ||
cf978ab2 DB |
636 | /* |
637 | * registering functions to load algorithms at runtime | |
1da177e4 | 638 | */ |
f451171c JD |
639 | static int __i2c_bit_add_bus(struct i2c_adapter *adap, |
640 | int (*add_adapter)(struct i2c_adapter *)) | |
1da177e4 LT |
641 | { |
642 | struct i2c_algo_bit_data *bit_adap = adap->algo_data; | |
af5a60ba | 643 | int ret; |
1da177e4 LT |
644 | |
645 | if (bit_test) { | |
d3b3e15d | 646 | ret = test_bus(adap); |
1bddab7f | 647 | if (bit_test >= 2 && ret < 0) |
1da177e4 LT |
648 | return -ENODEV; |
649 | } | |
650 | ||
1da177e4 | 651 | /* register new adapter to i2c module... */ |
1da177e4 | 652 | adap->algo = &i2c_bit_algo; |
8fcfef6e | 653 | adap->retries = 3; |
a94d306b NC |
654 | if (bit_adap->getscl == NULL) |
655 | adap->quirks = &i2c_bit_quirk_no_clk_stretch; | |
1da177e4 | 656 | |
2173ed0a WS |
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 | ||
af5a60ba JD |
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; | |
0f3b4838 JD |
672 | } |
673 | ||
674 | int i2c_bit_add_bus(struct i2c_adapter *adap) | |
675 | { | |
f451171c | 676 | return __i2c_bit_add_bus(adap, i2c_add_adapter); |
1da177e4 | 677 | } |
1da177e4 | 678 | EXPORT_SYMBOL(i2c_bit_add_bus); |
1da177e4 | 679 | |
0f3b4838 JD |
680 | int i2c_bit_add_numbered_bus(struct i2c_adapter *adap) |
681 | { | |
f451171c | 682 | return __i2c_bit_add_bus(adap, i2c_add_numbered_adapter); |
0f3b4838 JD |
683 | } |
684 | EXPORT_SYMBOL(i2c_bit_add_numbered_bus); | |
685 | ||
1da177e4 LT |
686 | MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>"); |
687 | MODULE_DESCRIPTION("I2C-Bus bit-banging algorithm"); | |
688 | MODULE_LICENSE("GPL"); |