Commit | Line | Data |
---|---|---|
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> | |
27 | #include <linux/slab.h> | |
28 | #include <linux/init.h> | |
29 | #include <linux/errno.h> | |
30 | #include <linux/sched.h> | |
31 | #include <linux/i2c.h> | |
32 | #include <linux/i2c-algo-bit.h> | |
33 | ||
34 | ||
35 | /* ----- global defines ----------------------------------------------- */ | |
1da177e4 | 36 | |
494dbb64 JD |
37 | #ifdef DEBUG |
38 | #define bit_dbg(level, dev, format, args...) \ | |
39 | do { \ | |
40 | if (i2c_debug >= level) \ | |
41 | dev_dbg(dev, format, ##args); \ | |
42 | } while (0) | |
43 | #else | |
44 | #define bit_dbg(level, dev, format, args...) \ | |
45 | do {} while (0) | |
46 | #endif /* DEBUG */ | |
1da177e4 LT |
47 | |
48 | /* ----- global variables --------------------------------------------- */ | |
49 | ||
1da177e4 | 50 | static int bit_test; /* see if the line-setting functions work */ |
494dbb64 JD |
51 | module_param(bit_test, bool, 0); |
52 | MODULE_PARM_DESC(bit_test, "Test the lines of the bus to see if it is stuck"); | |
53 | ||
54 | #ifdef DEBUG | |
55 | static int i2c_debug = 1; | |
56 | module_param(i2c_debug, int, S_IRUGO | S_IWUSR); | |
57 | MODULE_PARM_DESC(i2c_debug, | |
58 | "debug level - 0 off; 1 normal; 2 verbose; 3 very verbose"); | |
59 | #endif | |
1da177e4 LT |
60 | |
61 | /* --- setting states on the bus with the right timing: --------------- */ | |
62 | ||
cf978ab2 DB |
63 | #define setsda(adap, val) adap->setsda(adap->data, val) |
64 | #define setscl(adap, val) adap->setscl(adap->data, val) | |
65 | #define getsda(adap) adap->getsda(adap->data) | |
66 | #define getscl(adap) adap->getscl(adap->data) | |
1da177e4 LT |
67 | |
68 | static inline void sdalo(struct i2c_algo_bit_data *adap) | |
69 | { | |
cf978ab2 | 70 | setsda(adap, 0); |
424ed67c | 71 | udelay((adap->udelay + 1) / 2); |
1da177e4 LT |
72 | } |
73 | ||
74 | static inline void sdahi(struct i2c_algo_bit_data *adap) | |
75 | { | |
cf978ab2 | 76 | setsda(adap, 1); |
424ed67c | 77 | udelay((adap->udelay + 1) / 2); |
1da177e4 LT |
78 | } |
79 | ||
80 | static inline void scllo(struct i2c_algo_bit_data *adap) | |
81 | { | |
cf978ab2 | 82 | setscl(adap, 0); |
424ed67c | 83 | udelay(adap->udelay / 2); |
1da177e4 LT |
84 | } |
85 | ||
86 | /* | |
87 | * Raise scl line, and do checking for delays. This is necessary for slower | |
88 | * devices. | |
89 | */ | |
7b288a01 | 90 | static int sclhi(struct i2c_algo_bit_data *adap) |
1da177e4 LT |
91 | { |
92 | unsigned long start; | |
93 | ||
cf978ab2 | 94 | setscl(adap, 1); |
1da177e4 LT |
95 | |
96 | /* Not all adapters have scl sense line... */ | |
7b288a01 JD |
97 | if (!adap->getscl) |
98 | goto done; | |
1da177e4 | 99 | |
cf978ab2 DB |
100 | start = jiffies; |
101 | while (!getscl(adap)) { | |
102 | /* This hw knows how to read the clock line, so we wait | |
103 | * until it actually gets high. This is safer as some | |
104 | * chips may hold it low ("clock stretching") while they | |
105 | * are processing data internally. | |
106 | */ | |
107 | if (time_after_eq(jiffies, start + adap->timeout)) | |
1da177e4 | 108 | return -ETIMEDOUT; |
1da177e4 LT |
109 | cond_resched(); |
110 | } | |
494dbb64 JD |
111 | #ifdef DEBUG |
112 | if (jiffies != start && i2c_debug >= 3) | |
113 | pr_debug("i2c-algo-bit: needed %ld jiffies for SCL to go " | |
114 | "high\n", jiffies - start); | |
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 */ |
494dbb64 JD |
174 | bit_dbg(1, &i2c_adap->dev, "i2c_outb: 0x%02x, " |
175 | "timeout at bit #%d\n", (int)c, i); | |
1da177e4 | 176 | return -ETIMEDOUT; |
cf978ab2 DB |
177 | } |
178 | /* FIXME do arbitration here: | |
179 | * if (sb && !getsda(adap)) -> ouch! Get out of here. | |
180 | * | |
181 | * Report a unique code, so higher level code can retry | |
182 | * the whole (combined) message and *NOT* issue STOP. | |
1da177e4 | 183 | */ |
424ed67c | 184 | scllo(adap); |
1da177e4 LT |
185 | } |
186 | sdahi(adap); | |
cf978ab2 | 187 | if (sclhi(adap) < 0) { /* timeout */ |
494dbb64 JD |
188 | bit_dbg(1, &i2c_adap->dev, "i2c_outb: 0x%02x, " |
189 | "timeout at ack\n", (int)c); | |
190 | return -ETIMEDOUT; | |
cf978ab2 DB |
191 | } |
192 | ||
193 | /* read ack: SDA should be pulled down by slave, or it may | |
194 | * NAK (usually to report problems with the data we wrote). | |
195 | */ | |
494dbb64 JD |
196 | ack = !getsda(adap); /* ack: sda is pulled low -> success */ |
197 | bit_dbg(2, &i2c_adap->dev, "i2c_outb: 0x%02x %s\n", (int)c, | |
198 | ack ? "A" : "NA"); | |
1da177e4 | 199 | |
1da177e4 | 200 | scllo(adap); |
494dbb64 | 201 | return ack; |
1da177e4 LT |
202 | /* assert: scl is low (sda undef) */ |
203 | } | |
204 | ||
205 | ||
cf978ab2 | 206 | static int i2c_inb(struct i2c_adapter *i2c_adap) |
1da177e4 LT |
207 | { |
208 | /* read byte via i2c port, without start/stop sequence */ | |
209 | /* acknowledge is sent in i2c_read. */ | |
210 | int i; | |
cf978ab2 | 211 | unsigned char indata = 0; |
1da177e4 LT |
212 | struct i2c_algo_bit_data *adap = i2c_adap->algo_data; |
213 | ||
214 | /* assert: scl is low */ | |
215 | sdahi(adap); | |
cf978ab2 DB |
216 | for (i = 0; i < 8; i++) { |
217 | if (sclhi(adap) < 0) { /* timeout */ | |
494dbb64 JD |
218 | bit_dbg(1, &i2c_adap->dev, "i2c_inb: timeout at bit " |
219 | "#%d\n", 7 - i); | |
1da177e4 | 220 | return -ETIMEDOUT; |
cf978ab2 | 221 | } |
1da177e4 | 222 | indata *= 2; |
cf978ab2 | 223 | if (getsda(adap)) |
1da177e4 | 224 | indata |= 0x01; |
424ed67c JD |
225 | setscl(adap, 0); |
226 | udelay(i == 7 ? adap->udelay / 2 : adap->udelay); | |
1da177e4 LT |
227 | } |
228 | /* assert: scl is low */ | |
494dbb64 | 229 | return indata; |
1da177e4 LT |
230 | } |
231 | ||
232 | /* | |
233 | * Sanity check for the adapter hardware - check the reaction of | |
234 | * the bus lines only if it seems to be idle. | |
235 | */ | |
cf978ab2 DB |
236 | static int test_bus(struct i2c_algo_bit_data *adap, char *name) |
237 | { | |
238 | int scl, sda; | |
1da177e4 | 239 | |
cf978ab2 | 240 | if (adap->getscl == NULL) |
494dbb64 | 241 | pr_info("%s: Testing SDA only, SCL is not readable\n", name); |
1da177e4 | 242 | |
cf978ab2 DB |
243 | sda = getsda(adap); |
244 | scl = (adap->getscl == NULL) ? 1 : getscl(adap); | |
245 | if (!scl || !sda) { | |
494dbb64 | 246 | printk(KERN_WARNING "%s: bus seems to be busy\n", name); |
1da177e4 LT |
247 | goto bailout; |
248 | } | |
249 | ||
250 | sdalo(adap); | |
cf978ab2 DB |
251 | sda = getsda(adap); |
252 | scl = (adap->getscl == NULL) ? 1 : getscl(adap); | |
253 | if (sda) { | |
494dbb64 | 254 | printk(KERN_WARNING "%s: SDA stuck high!\n", name); |
1da177e4 LT |
255 | goto bailout; |
256 | } | |
cf978ab2 | 257 | if (!scl) { |
494dbb64 JD |
258 | printk(KERN_WARNING "%s: SCL unexpected low " |
259 | "while pulling SDA low!\n", name); | |
1da177e4 | 260 | goto bailout; |
cf978ab2 | 261 | } |
1da177e4 LT |
262 | |
263 | sdahi(adap); | |
cf978ab2 DB |
264 | sda = getsda(adap); |
265 | scl = (adap->getscl == NULL) ? 1 : getscl(adap); | |
266 | if (!sda) { | |
494dbb64 | 267 | printk(KERN_WARNING "%s: SDA stuck low!\n", name); |
1da177e4 LT |
268 | goto bailout; |
269 | } | |
cf978ab2 | 270 | if (!scl) { |
494dbb64 JD |
271 | printk(KERN_WARNING "%s: SCL unexpected low " |
272 | "while pulling SDA high!\n", name); | |
1da177e4 LT |
273 | goto bailout; |
274 | } | |
275 | ||
276 | scllo(adap); | |
cf978ab2 DB |
277 | sda = getsda(adap); |
278 | scl = (adap->getscl == NULL) ? 0 : getscl(adap); | |
279 | if (scl) { | |
494dbb64 | 280 | printk(KERN_WARNING "%s: SCL stuck high!\n", name); |
1da177e4 LT |
281 | goto bailout; |
282 | } | |
cf978ab2 | 283 | if (!sda) { |
494dbb64 JD |
284 | printk(KERN_WARNING "%s: SDA unexpected low " |
285 | "while pulling SCL low!\n", name); | |
1da177e4 LT |
286 | goto bailout; |
287 | } | |
cf978ab2 | 288 | |
1da177e4 | 289 | sclhi(adap); |
cf978ab2 DB |
290 | sda = getsda(adap); |
291 | scl = (adap->getscl == NULL) ? 1 : getscl(adap); | |
292 | if (!scl) { | |
494dbb64 | 293 | printk(KERN_WARNING "%s: SCL stuck low!\n", name); |
1da177e4 LT |
294 | goto bailout; |
295 | } | |
cf978ab2 | 296 | if (!sda) { |
494dbb64 JD |
297 | printk(KERN_WARNING "%s: SDA unexpected low " |
298 | "while pulling SCL high!\n", name); | |
1da177e4 LT |
299 | goto bailout; |
300 | } | |
494dbb64 | 301 | pr_info("%s: Test OK\n", name); |
1da177e4 LT |
302 | return 0; |
303 | bailout: | |
304 | sdahi(adap); | |
305 | sclhi(adap); | |
306 | return -ENODEV; | |
307 | } | |
308 | ||
309 | /* ----- Utility functions | |
310 | */ | |
311 | ||
312 | /* try_address tries to contact a chip for a number of | |
313 | * times before it gives up. | |
314 | * return values: | |
315 | * 1 chip answered | |
316 | * 0 chip did not answer | |
317 | * -x transmission error | |
318 | */ | |
7b288a01 | 319 | static int try_address(struct i2c_adapter *i2c_adap, |
1da177e4 LT |
320 | unsigned char addr, int retries) |
321 | { | |
322 | struct i2c_algo_bit_data *adap = i2c_adap->algo_data; | |
cf978ab2 DB |
323 | int i, ret = -1; |
324 | ||
325 | for (i = 0; i <= retries; i++) { | |
326 | ret = i2c_outb(i2c_adap, addr); | |
1ecac07a JD |
327 | if (ret == 1 || i == retries) |
328 | break; | |
494dbb64 | 329 | bit_dbg(3, &i2c_adap->dev, "emitting stop condition\n"); |
1da177e4 | 330 | i2c_stop(adap); |
1da177e4 | 331 | udelay(adap->udelay); |
424ed67c | 332 | yield(); |
494dbb64 | 333 | bit_dbg(3, &i2c_adap->dev, "emitting start condition\n"); |
424ed67c | 334 | i2c_start(adap); |
1da177e4 | 335 | } |
494dbb64 JD |
336 | if (i && ret) |
337 | bit_dbg(1, &i2c_adap->dev, "Used %d tries to %s client at " | |
338 | "0x%02x: %s\n", i + 1, | |
339 | addr & 1 ? "read from" : "write to", addr >> 1, | |
340 | ret == 1 ? "success" : "failed, timeout?"); | |
1da177e4 LT |
341 | return ret; |
342 | } | |
343 | ||
344 | static int sendbytes(struct i2c_adapter *i2c_adap, struct i2c_msg *msg) | |
345 | { | |
494dbb64 | 346 | const unsigned char *temp = msg->buf; |
1da177e4 | 347 | int count = msg->len; |
cf978ab2 | 348 | unsigned short nak_ok = msg->flags & I2C_M_IGNORE_NAK; |
1da177e4 | 349 | int retval; |
cf978ab2 | 350 | int wrcount = 0; |
1da177e4 LT |
351 | |
352 | while (count > 0) { | |
494dbb64 | 353 | retval = i2c_outb(i2c_adap, *temp); |
cf978ab2 DB |
354 | |
355 | /* OK/ACK; or ignored NAK */ | |
356 | if ((retval > 0) || (nak_ok && (retval == 0))) { | |
357 | count--; | |
1da177e4 LT |
358 | temp++; |
359 | wrcount++; | |
bf3e2d1d DB |
360 | |
361 | /* A slave NAKing the master means the slave didn't like | |
362 | * something about the data it saw. For example, maybe | |
363 | * the SMBus PEC was wrong. | |
364 | */ | |
365 | } else if (retval == 0) { | |
366 | dev_err(&i2c_adap->dev, "sendbytes: NAK bailout.\n"); | |
367 | return -EIO; | |
368 | ||
369 | /* Timeout; or (someday) lost arbitration | |
370 | * | |
371 | * FIXME Lost ARB implies retrying the transaction from | |
372 | * the first message, after the "winning" master issues | |
373 | * its STOP. As a rule, upper layer code has no reason | |
374 | * to know or care about this ... it is *NOT* an error. | |
375 | */ | |
376 | } else { | |
377 | dev_err(&i2c_adap->dev, "sendbytes: error %d\n", | |
378 | retval); | |
379 | return retval; | |
1da177e4 | 380 | } |
1da177e4 LT |
381 | } |
382 | return wrcount; | |
383 | } | |
384 | ||
939bc494 DB |
385 | static int acknak(struct i2c_adapter *i2c_adap, int is_ack) |
386 | { | |
387 | struct i2c_algo_bit_data *adap = i2c_adap->algo_data; | |
388 | ||
389 | /* assert: sda is high */ | |
390 | if (is_ack) /* send ack */ | |
391 | setsda(adap, 0); | |
392 | udelay((adap->udelay + 1) / 2); | |
393 | if (sclhi(adap) < 0) { /* timeout */ | |
394 | dev_err(&i2c_adap->dev, "readbytes: ack/nak timeout\n"); | |
395 | return -ETIMEDOUT; | |
396 | } | |
397 | scllo(adap); | |
398 | return 0; | |
399 | } | |
400 | ||
7b288a01 | 401 | static int readbytes(struct i2c_adapter *i2c_adap, struct i2c_msg *msg) |
1da177e4 LT |
402 | { |
403 | int inval; | |
cf978ab2 | 404 | int rdcount = 0; /* counts bytes read */ |
494dbb64 | 405 | unsigned char *temp = msg->buf; |
1da177e4 | 406 | int count = msg->len; |
939bc494 | 407 | const unsigned flags = msg->flags; |
1da177e4 LT |
408 | |
409 | while (count > 0) { | |
410 | inval = i2c_inb(i2c_adap); | |
cf978ab2 | 411 | if (inval >= 0) { |
1da177e4 LT |
412 | *temp = inval; |
413 | rdcount++; | |
414 | } else { /* read timed out */ | |
1da177e4 LT |
415 | break; |
416 | } | |
417 | ||
418 | temp++; | |
419 | count--; | |
420 | ||
3c4bb241 JD |
421 | /* Some SMBus transactions require that we receive the |
422 | transaction length as the first read byte. */ | |
939bc494 | 423 | if (rdcount == 1 && (flags & I2C_M_RECV_LEN)) { |
3c4bb241 | 424 | if (inval <= 0 || inval > I2C_SMBUS_BLOCK_MAX) { |
939bc494 DB |
425 | if (!(flags & I2C_M_NO_RD_ACK)) |
426 | acknak(i2c_adap, 0); | |
494dbb64 JD |
427 | dev_err(&i2c_adap->dev, "readbytes: invalid " |
428 | "block length (%d)\n", inval); | |
3c4bb241 JD |
429 | return -EREMOTEIO; |
430 | } | |
431 | /* The original count value accounts for the extra | |
432 | bytes, that is, either 1 for a regular transaction, | |
433 | or 2 for a PEC transaction. */ | |
434 | count += inval; | |
435 | msg->len += inval; | |
436 | } | |
939bc494 DB |
437 | |
438 | bit_dbg(2, &i2c_adap->dev, "readbytes: 0x%02x %s\n", | |
439 | inval, | |
440 | (flags & I2C_M_NO_RD_ACK) | |
441 | ? "(no ack/nak)" | |
442 | : (count ? "A" : "NA")); | |
443 | ||
444 | if (!(flags & I2C_M_NO_RD_ACK)) { | |
445 | inval = acknak(i2c_adap, count); | |
446 | if (inval < 0) | |
447 | return inval; | |
448 | } | |
1da177e4 LT |
449 | } |
450 | return rdcount; | |
451 | } | |
452 | ||
453 | /* doAddress initiates the transfer by generating the start condition (in | |
454 | * try_address) and transmits the address in the necessary format to handle | |
455 | * reads, writes as well as 10bit-addresses. | |
456 | * returns: | |
457 | * 0 everything went okay, the chip ack'ed, or IGNORE_NAK flag was set | |
458 | * -x an error occurred (like: -EREMOTEIO if the device did not answer, or | |
cf978ab2 | 459 | * -ETIMEDOUT, for example if the lines are stuck...) |
1da177e4 | 460 | */ |
7b288a01 | 461 | static int bit_doAddress(struct i2c_adapter *i2c_adap, struct i2c_msg *msg) |
1da177e4 LT |
462 | { |
463 | unsigned short flags = msg->flags; | |
464 | unsigned short nak_ok = msg->flags & I2C_M_IGNORE_NAK; | |
465 | struct i2c_algo_bit_data *adap = i2c_adap->algo_data; | |
466 | ||
467 | unsigned char addr; | |
468 | int ret, retries; | |
469 | ||
470 | retries = nak_ok ? 0 : i2c_adap->retries; | |
cf978ab2 DB |
471 | |
472 | if (flags & I2C_M_TEN) { | |
1da177e4 | 473 | /* a ten bit address */ |
cf978ab2 | 474 | addr = 0xf0 | ((msg->addr >> 7) & 0x03); |
494dbb64 | 475 | bit_dbg(2, &i2c_adap->dev, "addr0: %d\n", addr); |
1da177e4 LT |
476 | /* try extended address code...*/ |
477 | ret = try_address(i2c_adap, addr, retries); | |
478 | if ((ret != 1) && !nak_ok) { | |
494dbb64 JD |
479 | dev_err(&i2c_adap->dev, |
480 | "died at extended address code\n"); | |
1da177e4 LT |
481 | return -EREMOTEIO; |
482 | } | |
483 | /* the remaining 8 bit address */ | |
cf978ab2 | 484 | ret = i2c_outb(i2c_adap, msg->addr & 0x7f); |
1da177e4 LT |
485 | if ((ret != 1) && !nak_ok) { |
486 | /* the chip did not ack / xmission error occurred */ | |
494dbb64 | 487 | dev_err(&i2c_adap->dev, "died at 2nd address code\n"); |
1da177e4 LT |
488 | return -EREMOTEIO; |
489 | } | |
cf978ab2 | 490 | if (flags & I2C_M_RD) { |
494dbb64 JD |
491 | bit_dbg(3, &i2c_adap->dev, "emitting repeated " |
492 | "start condition\n"); | |
1da177e4 LT |
493 | i2c_repstart(adap); |
494 | /* okay, now switch into reading mode */ | |
495 | addr |= 0x01; | |
496 | ret = try_address(i2c_adap, addr, retries); | |
cf978ab2 | 497 | if ((ret != 1) && !nak_ok) { |
494dbb64 JD |
498 | dev_err(&i2c_adap->dev, |
499 | "died at repeated address code\n"); | |
1da177e4 LT |
500 | return -EREMOTEIO; |
501 | } | |
502 | } | |
503 | } else { /* normal 7bit address */ | |
cf978ab2 DB |
504 | addr = msg->addr << 1; |
505 | if (flags & I2C_M_RD) | |
1da177e4 | 506 | addr |= 1; |
cf978ab2 | 507 | if (flags & I2C_M_REV_DIR_ADDR) |
1da177e4 LT |
508 | addr ^= 1; |
509 | ret = try_address(i2c_adap, addr, retries); | |
cf978ab2 | 510 | if ((ret != 1) && !nak_ok) |
1da177e4 LT |
511 | return -EREMOTEIO; |
512 | } | |
513 | ||
514 | return 0; | |
515 | } | |
516 | ||
517 | static int bit_xfer(struct i2c_adapter *i2c_adap, | |
518 | struct i2c_msg msgs[], int num) | |
519 | { | |
520 | struct i2c_msg *pmsg; | |
521 | struct i2c_algo_bit_data *adap = i2c_adap->algo_data; | |
cf978ab2 | 522 | int i, ret; |
1da177e4 LT |
523 | unsigned short nak_ok; |
524 | ||
494dbb64 | 525 | bit_dbg(3, &i2c_adap->dev, "emitting start condition\n"); |
1da177e4 | 526 | i2c_start(adap); |
cf978ab2 | 527 | for (i = 0; i < num; i++) { |
1da177e4 | 528 | pmsg = &msgs[i]; |
cf978ab2 | 529 | nak_ok = pmsg->flags & I2C_M_IGNORE_NAK; |
1da177e4 LT |
530 | if (!(pmsg->flags & I2C_M_NOSTART)) { |
531 | if (i) { | |
494dbb64 JD |
532 | bit_dbg(3, &i2c_adap->dev, "emitting " |
533 | "repeated start condition\n"); | |
1da177e4 LT |
534 | i2c_repstart(adap); |
535 | } | |
536 | ret = bit_doAddress(i2c_adap, pmsg); | |
537 | if ((ret != 0) && !nak_ok) { | |
494dbb64 JD |
538 | bit_dbg(1, &i2c_adap->dev, "NAK from " |
539 | "device addr 0x%02x msg #%d\n", | |
540 | msgs[i].addr, i); | |
1ecac07a | 541 | goto bailout; |
1da177e4 LT |
542 | } |
543 | } | |
cf978ab2 | 544 | if (pmsg->flags & I2C_M_RD) { |
1da177e4 LT |
545 | /* read bytes into buffer*/ |
546 | ret = readbytes(i2c_adap, pmsg); | |
494dbb64 JD |
547 | if (ret >= 1) |
548 | bit_dbg(2, &i2c_adap->dev, "read %d byte%s\n", | |
549 | ret, ret == 1 ? "" : "s"); | |
1ecac07a JD |
550 | if (ret < pmsg->len) { |
551 | if (ret >= 0) | |
552 | ret = -EREMOTEIO; | |
553 | goto bailout; | |
1da177e4 LT |
554 | } |
555 | } else { | |
556 | /* write bytes from buffer */ | |
557 | ret = sendbytes(i2c_adap, pmsg); | |
494dbb64 JD |
558 | if (ret >= 1) |
559 | bit_dbg(2, &i2c_adap->dev, "wrote %d byte%s\n", | |
560 | ret, ret == 1 ? "" : "s"); | |
1ecac07a JD |
561 | if (ret < pmsg->len) { |
562 | if (ret >= 0) | |
563 | ret = -EREMOTEIO; | |
564 | goto bailout; | |
1da177e4 LT |
565 | } |
566 | } | |
567 | } | |
1ecac07a JD |
568 | ret = i; |
569 | ||
570 | bailout: | |
494dbb64 | 571 | bit_dbg(3, &i2c_adap->dev, "emitting stop condition\n"); |
1da177e4 | 572 | i2c_stop(adap); |
1ecac07a | 573 | return ret; |
1da177e4 LT |
574 | } |
575 | ||
576 | static u32 bit_func(struct i2c_adapter *adap) | |
577 | { | |
cf978ab2 | 578 | return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | |
3c4bb241 JD |
579 | I2C_FUNC_SMBUS_READ_BLOCK_DATA | |
580 | I2C_FUNC_SMBUS_BLOCK_PROC_CALL | | |
1da177e4 LT |
581 | I2C_FUNC_10BIT_ADDR | I2C_FUNC_PROTOCOL_MANGLING; |
582 | } | |
583 | ||
584 | ||
585 | /* -----exported algorithm data: ------------------------------------- */ | |
586 | ||
9e11a9fb | 587 | static const struct i2c_algorithm i2c_bit_algo = { |
1da177e4 LT |
588 | .master_xfer = bit_xfer, |
589 | .functionality = bit_func, | |
590 | }; | |
591 | ||
cf978ab2 DB |
592 | /* |
593 | * registering functions to load algorithms at runtime | |
1da177e4 | 594 | */ |
0f3b4838 | 595 | static int i2c_bit_prepare_bus(struct i2c_adapter *adap) |
1da177e4 LT |
596 | { |
597 | struct i2c_algo_bit_data *bit_adap = adap->algo_data; | |
598 | ||
599 | if (bit_test) { | |
600 | int ret = test_bus(bit_adap, adap->name); | |
cf978ab2 | 601 | if (ret < 0) |
1da177e4 LT |
602 | return -ENODEV; |
603 | } | |
604 | ||
1da177e4 | 605 | /* register new adapter to i2c module... */ |
1da177e4 LT |
606 | adap->algo = &i2c_bit_algo; |
607 | ||
608 | adap->timeout = 100; /* default values, should */ | |
609 | adap->retries = 3; /* be replaced by defines */ | |
610 | ||
0f3b4838 JD |
611 | return 0; |
612 | } | |
613 | ||
614 | int i2c_bit_add_bus(struct i2c_adapter *adap) | |
615 | { | |
616 | int err; | |
617 | ||
618 | err = i2c_bit_prepare_bus(adap); | |
619 | if (err) | |
620 | return err; | |
621 | ||
b39ad0cf | 622 | return i2c_add_adapter(adap); |
1da177e4 | 623 | } |
1da177e4 | 624 | EXPORT_SYMBOL(i2c_bit_add_bus); |
1da177e4 | 625 | |
0f3b4838 JD |
626 | int i2c_bit_add_numbered_bus(struct i2c_adapter *adap) |
627 | { | |
628 | int err; | |
629 | ||
630 | err = i2c_bit_prepare_bus(adap); | |
631 | if (err) | |
632 | return err; | |
633 | ||
634 | return i2c_add_numbered_adapter(adap); | |
635 | } | |
636 | EXPORT_SYMBOL(i2c_bit_add_numbered_bus); | |
637 | ||
1da177e4 LT |
638 | MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>"); |
639 | MODULE_DESCRIPTION("I2C-Bus bit-banging algorithm"); | |
640 | MODULE_LICENSE("GPL"); |