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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 */ |
494dbb64 JD |
50 | module_param(bit_test, bool, 0); |
51 | MODULE_PARM_DESC(bit_test, "Test the lines of the bus to see if it is stuck"); | |
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 | */ | |
0cdba07b | 106 | if (time_after(jiffies, start + adap->timeout)) |
1da177e4 | 107 | return -ETIMEDOUT; |
1da177e4 LT |
108 | cond_resched(); |
109 | } | |
494dbb64 JD |
110 | #ifdef DEBUG |
111 | if (jiffies != start && i2c_debug >= 3) | |
112 | pr_debug("i2c-algo-bit: needed %ld jiffies for SCL to go " | |
113 | "high\n", jiffies - start); | |
114 | #endif | |
7b288a01 JD |
115 | |
116 | done: | |
1da177e4 LT |
117 | udelay(adap->udelay); |
118 | return 0; | |
cf978ab2 | 119 | } |
1da177e4 LT |
120 | |
121 | ||
122 | /* --- other auxiliary functions -------------------------------------- */ | |
cf978ab2 | 123 | static void i2c_start(struct i2c_algo_bit_data *adap) |
1da177e4 LT |
124 | { |
125 | /* assert: scl, sda are high */ | |
424ed67c JD |
126 | setsda(adap, 0); |
127 | udelay(adap->udelay); | |
1da177e4 LT |
128 | scllo(adap); |
129 | } | |
130 | ||
cf978ab2 | 131 | static void i2c_repstart(struct i2c_algo_bit_data *adap) |
1da177e4 | 132 | { |
424ed67c | 133 | /* assert: scl is low */ |
424ed67c | 134 | sdahi(adap); |
1da177e4 | 135 | sclhi(adap); |
424ed67c JD |
136 | setsda(adap, 0); |
137 | udelay(adap->udelay); | |
1da177e4 LT |
138 | scllo(adap); |
139 | } | |
140 | ||
141 | ||
cf978ab2 | 142 | static void i2c_stop(struct i2c_algo_bit_data *adap) |
1da177e4 | 143 | { |
1da177e4 LT |
144 | /* assert: scl is low */ |
145 | sdalo(adap); | |
cf978ab2 | 146 | sclhi(adap); |
424ed67c JD |
147 | setsda(adap, 1); |
148 | udelay(adap->udelay); | |
1da177e4 LT |
149 | } |
150 | ||
151 | ||
152 | ||
cf978ab2 | 153 | /* send a byte without start cond., look for arbitration, |
1da177e4 LT |
154 | check ackn. from slave */ |
155 | /* returns: | |
156 | * 1 if the device acknowledged | |
157 | * 0 if the device did not ack | |
158 | * -ETIMEDOUT if an error occurred (while raising the scl line) | |
159 | */ | |
494dbb64 | 160 | static int i2c_outb(struct i2c_adapter *i2c_adap, unsigned char c) |
1da177e4 LT |
161 | { |
162 | int i; | |
163 | int sb; | |
164 | int ack; | |
165 | struct i2c_algo_bit_data *adap = i2c_adap->algo_data; | |
166 | ||
167 | /* assert: scl is low */ | |
cf978ab2 | 168 | for (i = 7; i >= 0; i--) { |
494dbb64 | 169 | sb = (c >> i) & 1; |
cf978ab2 | 170 | setsda(adap, sb); |
424ed67c | 171 | udelay((adap->udelay + 1) / 2); |
cf978ab2 | 172 | if (sclhi(adap) < 0) { /* timed out */ |
494dbb64 JD |
173 | bit_dbg(1, &i2c_adap->dev, "i2c_outb: 0x%02x, " |
174 | "timeout at bit #%d\n", (int)c, i); | |
1da177e4 | 175 | return -ETIMEDOUT; |
cf978ab2 DB |
176 | } |
177 | /* FIXME do arbitration here: | |
178 | * if (sb && !getsda(adap)) -> ouch! Get out of here. | |
179 | * | |
180 | * Report a unique code, so higher level code can retry | |
181 | * the whole (combined) message and *NOT* issue STOP. | |
1da177e4 | 182 | */ |
424ed67c | 183 | scllo(adap); |
1da177e4 LT |
184 | } |
185 | sdahi(adap); | |
cf978ab2 | 186 | if (sclhi(adap) < 0) { /* timeout */ |
494dbb64 JD |
187 | bit_dbg(1, &i2c_adap->dev, "i2c_outb: 0x%02x, " |
188 | "timeout at ack\n", (int)c); | |
189 | return -ETIMEDOUT; | |
cf978ab2 DB |
190 | } |
191 | ||
192 | /* read ack: SDA should be pulled down by slave, or it may | |
193 | * NAK (usually to report problems with the data we wrote). | |
194 | */ | |
494dbb64 JD |
195 | ack = !getsda(adap); /* ack: sda is pulled low -> success */ |
196 | bit_dbg(2, &i2c_adap->dev, "i2c_outb: 0x%02x %s\n", (int)c, | |
197 | ack ? "A" : "NA"); | |
1da177e4 | 198 | |
1da177e4 | 199 | scllo(adap); |
494dbb64 | 200 | return ack; |
1da177e4 LT |
201 | /* assert: scl is low (sda undef) */ |
202 | } | |
203 | ||
204 | ||
cf978ab2 | 205 | static int i2c_inb(struct i2c_adapter *i2c_adap) |
1da177e4 LT |
206 | { |
207 | /* read byte via i2c port, without start/stop sequence */ | |
208 | /* acknowledge is sent in i2c_read. */ | |
209 | int i; | |
cf978ab2 | 210 | unsigned char indata = 0; |
1da177e4 LT |
211 | struct i2c_algo_bit_data *adap = i2c_adap->algo_data; |
212 | ||
213 | /* assert: scl is low */ | |
214 | sdahi(adap); | |
cf978ab2 DB |
215 | for (i = 0; i < 8; i++) { |
216 | if (sclhi(adap) < 0) { /* timeout */ | |
494dbb64 JD |
217 | bit_dbg(1, &i2c_adap->dev, "i2c_inb: timeout at bit " |
218 | "#%d\n", 7 - i); | |
1da177e4 | 219 | return -ETIMEDOUT; |
cf978ab2 | 220 | } |
1da177e4 | 221 | indata *= 2; |
cf978ab2 | 222 | if (getsda(adap)) |
1da177e4 | 223 | indata |= 0x01; |
424ed67c JD |
224 | setscl(adap, 0); |
225 | udelay(i == 7 ? adap->udelay / 2 : adap->udelay); | |
1da177e4 LT |
226 | } |
227 | /* assert: scl is low */ | |
494dbb64 | 228 | return indata; |
1da177e4 LT |
229 | } |
230 | ||
231 | /* | |
232 | * Sanity check for the adapter hardware - check the reaction of | |
233 | * the bus lines only if it seems to be idle. | |
234 | */ | |
cf978ab2 DB |
235 | static int test_bus(struct i2c_algo_bit_data *adap, char *name) |
236 | { | |
237 | int scl, sda; | |
1da177e4 | 238 | |
cf978ab2 | 239 | if (adap->getscl == NULL) |
494dbb64 | 240 | pr_info("%s: Testing SDA only, SCL is not readable\n", name); |
1da177e4 | 241 | |
cf978ab2 DB |
242 | sda = getsda(adap); |
243 | scl = (adap->getscl == NULL) ? 1 : getscl(adap); | |
244 | if (!scl || !sda) { | |
494dbb64 | 245 | printk(KERN_WARNING "%s: bus seems to be busy\n", name); |
1da177e4 LT |
246 | goto bailout; |
247 | } | |
248 | ||
249 | sdalo(adap); | |
cf978ab2 DB |
250 | sda = getsda(adap); |
251 | scl = (adap->getscl == NULL) ? 1 : getscl(adap); | |
252 | if (sda) { | |
494dbb64 | 253 | printk(KERN_WARNING "%s: SDA stuck high!\n", name); |
1da177e4 LT |
254 | goto bailout; |
255 | } | |
cf978ab2 | 256 | if (!scl) { |
494dbb64 JD |
257 | printk(KERN_WARNING "%s: SCL unexpected low " |
258 | "while pulling SDA low!\n", name); | |
1da177e4 | 259 | goto bailout; |
cf978ab2 | 260 | } |
1da177e4 LT |
261 | |
262 | sdahi(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 low!\n", name); |
1da177e4 LT |
267 | goto bailout; |
268 | } | |
cf978ab2 | 269 | if (!scl) { |
494dbb64 JD |
270 | printk(KERN_WARNING "%s: SCL unexpected low " |
271 | "while pulling SDA high!\n", name); | |
1da177e4 LT |
272 | goto bailout; |
273 | } | |
274 | ||
275 | scllo(adap); | |
cf978ab2 DB |
276 | sda = getsda(adap); |
277 | scl = (adap->getscl == NULL) ? 0 : getscl(adap); | |
278 | if (scl) { | |
494dbb64 | 279 | printk(KERN_WARNING "%s: SCL stuck high!\n", name); |
1da177e4 LT |
280 | goto bailout; |
281 | } | |
cf978ab2 | 282 | if (!sda) { |
494dbb64 JD |
283 | printk(KERN_WARNING "%s: SDA unexpected low " |
284 | "while pulling SCL low!\n", name); | |
1da177e4 LT |
285 | goto bailout; |
286 | } | |
cf978ab2 | 287 | |
1da177e4 | 288 | sclhi(adap); |
cf978ab2 DB |
289 | sda = getsda(adap); |
290 | scl = (adap->getscl == NULL) ? 1 : getscl(adap); | |
291 | if (!scl) { | |
494dbb64 | 292 | printk(KERN_WARNING "%s: SCL stuck low!\n", name); |
1da177e4 LT |
293 | goto bailout; |
294 | } | |
cf978ab2 | 295 | if (!sda) { |
494dbb64 JD |
296 | printk(KERN_WARNING "%s: SDA unexpected low " |
297 | "while pulling SCL high!\n", name); | |
1da177e4 LT |
298 | goto bailout; |
299 | } | |
494dbb64 | 300 | pr_info("%s: Test OK\n", name); |
1da177e4 LT |
301 | return 0; |
302 | bailout: | |
303 | sdahi(adap); | |
304 | sclhi(adap); | |
305 | return -ENODEV; | |
306 | } | |
307 | ||
308 | /* ----- Utility functions | |
309 | */ | |
310 | ||
311 | /* try_address tries to contact a chip for a number of | |
312 | * times before it gives up. | |
313 | * return values: | |
314 | * 1 chip answered | |
315 | * 0 chip did not answer | |
316 | * -x transmission error | |
317 | */ | |
7b288a01 | 318 | static int try_address(struct i2c_adapter *i2c_adap, |
1da177e4 LT |
319 | unsigned char addr, int retries) |
320 | { | |
321 | struct i2c_algo_bit_data *adap = i2c_adap->algo_data; | |
97140342 | 322 | int i, ret = 0; |
cf978ab2 DB |
323 | |
324 | for (i = 0; i <= retries; i++) { | |
325 | ret = i2c_outb(i2c_adap, addr); | |
1ecac07a JD |
326 | if (ret == 1 || i == retries) |
327 | break; | |
494dbb64 | 328 | bit_dbg(3, &i2c_adap->dev, "emitting stop condition\n"); |
1da177e4 | 329 | i2c_stop(adap); |
1da177e4 | 330 | udelay(adap->udelay); |
424ed67c | 331 | yield(); |
494dbb64 | 332 | bit_dbg(3, &i2c_adap->dev, "emitting start condition\n"); |
424ed67c | 333 | i2c_start(adap); |
1da177e4 | 334 | } |
494dbb64 JD |
335 | if (i && ret) |
336 | bit_dbg(1, &i2c_adap->dev, "Used %d tries to %s client at " | |
337 | "0x%02x: %s\n", i + 1, | |
338 | addr & 1 ? "read from" : "write to", addr >> 1, | |
339 | ret == 1 ? "success" : "failed, timeout?"); | |
1da177e4 LT |
340 | return ret; |
341 | } | |
342 | ||
343 | static int sendbytes(struct i2c_adapter *i2c_adap, struct i2c_msg *msg) | |
344 | { | |
494dbb64 | 345 | const unsigned char *temp = msg->buf; |
1da177e4 | 346 | int count = msg->len; |
cf978ab2 | 347 | unsigned short nak_ok = msg->flags & I2C_M_IGNORE_NAK; |
1da177e4 | 348 | int retval; |
cf978ab2 | 349 | int wrcount = 0; |
1da177e4 LT |
350 | |
351 | while (count > 0) { | |
494dbb64 | 352 | retval = i2c_outb(i2c_adap, *temp); |
cf978ab2 DB |
353 | |
354 | /* OK/ACK; or ignored NAK */ | |
355 | if ((retval > 0) || (nak_ok && (retval == 0))) { | |
356 | count--; | |
1da177e4 LT |
357 | temp++; |
358 | wrcount++; | |
bf3e2d1d DB |
359 | |
360 | /* A slave NAKing the master means the slave didn't like | |
361 | * something about the data it saw. For example, maybe | |
362 | * the SMBus PEC was wrong. | |
363 | */ | |
364 | } else if (retval == 0) { | |
365 | dev_err(&i2c_adap->dev, "sendbytes: NAK bailout.\n"); | |
366 | return -EIO; | |
367 | ||
368 | /* Timeout; or (someday) lost arbitration | |
369 | * | |
370 | * FIXME Lost ARB implies retrying the transaction from | |
371 | * the first message, after the "winning" master issues | |
372 | * its STOP. As a rule, upper layer code has no reason | |
373 | * to know or care about this ... it is *NOT* an error. | |
374 | */ | |
375 | } else { | |
376 | dev_err(&i2c_adap->dev, "sendbytes: error %d\n", | |
377 | retval); | |
378 | return retval; | |
1da177e4 | 379 | } |
1da177e4 LT |
380 | } |
381 | return wrcount; | |
382 | } | |
383 | ||
939bc494 DB |
384 | static int acknak(struct i2c_adapter *i2c_adap, int is_ack) |
385 | { | |
386 | struct i2c_algo_bit_data *adap = i2c_adap->algo_data; | |
387 | ||
388 | /* assert: sda is high */ | |
389 | if (is_ack) /* send ack */ | |
390 | setsda(adap, 0); | |
391 | udelay((adap->udelay + 1) / 2); | |
392 | if (sclhi(adap) < 0) { /* timeout */ | |
393 | dev_err(&i2c_adap->dev, "readbytes: ack/nak timeout\n"); | |
394 | return -ETIMEDOUT; | |
395 | } | |
396 | scllo(adap); | |
397 | return 0; | |
398 | } | |
399 | ||
7b288a01 | 400 | static int readbytes(struct i2c_adapter *i2c_adap, struct i2c_msg *msg) |
1da177e4 LT |
401 | { |
402 | int inval; | |
cf978ab2 | 403 | int rdcount = 0; /* counts bytes read */ |
494dbb64 | 404 | unsigned char *temp = msg->buf; |
1da177e4 | 405 | int count = msg->len; |
939bc494 | 406 | const unsigned flags = msg->flags; |
1da177e4 LT |
407 | |
408 | while (count > 0) { | |
409 | inval = i2c_inb(i2c_adap); | |
cf978ab2 | 410 | if (inval >= 0) { |
1da177e4 LT |
411 | *temp = inval; |
412 | rdcount++; | |
413 | } else { /* read timed out */ | |
1da177e4 LT |
414 | break; |
415 | } | |
416 | ||
417 | temp++; | |
418 | count--; | |
419 | ||
3c4bb241 JD |
420 | /* Some SMBus transactions require that we receive the |
421 | transaction length as the first read byte. */ | |
939bc494 | 422 | if (rdcount == 1 && (flags & I2C_M_RECV_LEN)) { |
3c4bb241 | 423 | if (inval <= 0 || inval > I2C_SMBUS_BLOCK_MAX) { |
939bc494 DB |
424 | if (!(flags & I2C_M_NO_RD_ACK)) |
425 | acknak(i2c_adap, 0); | |
494dbb64 JD |
426 | dev_err(&i2c_adap->dev, "readbytes: invalid " |
427 | "block length (%d)\n", inval); | |
3c4bb241 JD |
428 | return -EREMOTEIO; |
429 | } | |
430 | /* The original count value accounts for the extra | |
431 | bytes, that is, either 1 for a regular transaction, | |
432 | or 2 for a PEC transaction. */ | |
433 | count += inval; | |
434 | msg->len += inval; | |
435 | } | |
939bc494 DB |
436 | |
437 | bit_dbg(2, &i2c_adap->dev, "readbytes: 0x%02x %s\n", | |
438 | inval, | |
439 | (flags & I2C_M_NO_RD_ACK) | |
440 | ? "(no ack/nak)" | |
441 | : (count ? "A" : "NA")); | |
442 | ||
443 | if (!(flags & I2C_M_NO_RD_ACK)) { | |
444 | inval = acknak(i2c_adap, count); | |
445 | if (inval < 0) | |
446 | return inval; | |
447 | } | |
1da177e4 LT |
448 | } |
449 | return rdcount; | |
450 | } | |
451 | ||
452 | /* doAddress initiates the transfer by generating the start condition (in | |
453 | * try_address) and transmits the address in the necessary format to handle | |
454 | * reads, writes as well as 10bit-addresses. | |
455 | * returns: | |
456 | * 0 everything went okay, the chip ack'ed, or IGNORE_NAK flag was set | |
457 | * -x an error occurred (like: -EREMOTEIO if the device did not answer, or | |
cf978ab2 | 458 | * -ETIMEDOUT, for example if the lines are stuck...) |
1da177e4 | 459 | */ |
7b288a01 | 460 | static int bit_doAddress(struct i2c_adapter *i2c_adap, struct i2c_msg *msg) |
1da177e4 LT |
461 | { |
462 | unsigned short flags = msg->flags; | |
463 | unsigned short nak_ok = msg->flags & I2C_M_IGNORE_NAK; | |
464 | struct i2c_algo_bit_data *adap = i2c_adap->algo_data; | |
465 | ||
466 | unsigned char addr; | |
467 | int ret, retries; | |
468 | ||
469 | retries = nak_ok ? 0 : i2c_adap->retries; | |
cf978ab2 DB |
470 | |
471 | if (flags & I2C_M_TEN) { | |
1da177e4 | 472 | /* a ten bit address */ |
cf978ab2 | 473 | addr = 0xf0 | ((msg->addr >> 7) & 0x03); |
494dbb64 | 474 | bit_dbg(2, &i2c_adap->dev, "addr0: %d\n", addr); |
1da177e4 LT |
475 | /* try extended address code...*/ |
476 | ret = try_address(i2c_adap, addr, retries); | |
477 | if ((ret != 1) && !nak_ok) { | |
494dbb64 JD |
478 | dev_err(&i2c_adap->dev, |
479 | "died at extended address code\n"); | |
1da177e4 LT |
480 | return -EREMOTEIO; |
481 | } | |
482 | /* the remaining 8 bit address */ | |
cf978ab2 | 483 | ret = i2c_outb(i2c_adap, msg->addr & 0x7f); |
1da177e4 LT |
484 | if ((ret != 1) && !nak_ok) { |
485 | /* the chip did not ack / xmission error occurred */ | |
494dbb64 | 486 | dev_err(&i2c_adap->dev, "died at 2nd address code\n"); |
1da177e4 LT |
487 | return -EREMOTEIO; |
488 | } | |
cf978ab2 | 489 | if (flags & I2C_M_RD) { |
494dbb64 JD |
490 | bit_dbg(3, &i2c_adap->dev, "emitting repeated " |
491 | "start condition\n"); | |
1da177e4 LT |
492 | i2c_repstart(adap); |
493 | /* okay, now switch into reading mode */ | |
494 | addr |= 0x01; | |
495 | ret = try_address(i2c_adap, addr, retries); | |
cf978ab2 | 496 | if ((ret != 1) && !nak_ok) { |
494dbb64 JD |
497 | dev_err(&i2c_adap->dev, |
498 | "died at repeated address code\n"); | |
1da177e4 LT |
499 | return -EREMOTEIO; |
500 | } | |
501 | } | |
502 | } else { /* normal 7bit address */ | |
cf978ab2 DB |
503 | addr = msg->addr << 1; |
504 | if (flags & I2C_M_RD) | |
1da177e4 | 505 | addr |= 1; |
cf978ab2 | 506 | if (flags & I2C_M_REV_DIR_ADDR) |
1da177e4 LT |
507 | addr ^= 1; |
508 | ret = try_address(i2c_adap, addr, retries); | |
cf978ab2 | 509 | if ((ret != 1) && !nak_ok) |
97140342 | 510 | return -ENXIO; |
1da177e4 LT |
511 | } |
512 | ||
513 | return 0; | |
514 | } | |
515 | ||
516 | static int bit_xfer(struct i2c_adapter *i2c_adap, | |
517 | struct i2c_msg msgs[], int num) | |
518 | { | |
519 | struct i2c_msg *pmsg; | |
520 | struct i2c_algo_bit_data *adap = i2c_adap->algo_data; | |
cf978ab2 | 521 | int i, ret; |
1da177e4 LT |
522 | unsigned short nak_ok; |
523 | ||
0a9c1475 JD |
524 | if (adap->pre_xfer) { |
525 | ret = adap->pre_xfer(i2c_adap); | |
526 | if (ret < 0) | |
527 | return ret; | |
528 | } | |
529 | ||
494dbb64 | 530 | bit_dbg(3, &i2c_adap->dev, "emitting start condition\n"); |
1da177e4 | 531 | i2c_start(adap); |
cf978ab2 | 532 | for (i = 0; i < num; i++) { |
1da177e4 | 533 | pmsg = &msgs[i]; |
cf978ab2 | 534 | nak_ok = pmsg->flags & I2C_M_IGNORE_NAK; |
1da177e4 LT |
535 | if (!(pmsg->flags & I2C_M_NOSTART)) { |
536 | if (i) { | |
494dbb64 JD |
537 | bit_dbg(3, &i2c_adap->dev, "emitting " |
538 | "repeated start condition\n"); | |
1da177e4 LT |
539 | i2c_repstart(adap); |
540 | } | |
541 | ret = bit_doAddress(i2c_adap, pmsg); | |
542 | if ((ret != 0) && !nak_ok) { | |
494dbb64 JD |
543 | bit_dbg(1, &i2c_adap->dev, "NAK from " |
544 | "device addr 0x%02x msg #%d\n", | |
545 | msgs[i].addr, i); | |
1ecac07a | 546 | goto bailout; |
1da177e4 LT |
547 | } |
548 | } | |
cf978ab2 | 549 | if (pmsg->flags & I2C_M_RD) { |
1da177e4 LT |
550 | /* read bytes into buffer*/ |
551 | ret = readbytes(i2c_adap, pmsg); | |
494dbb64 JD |
552 | if (ret >= 1) |
553 | bit_dbg(2, &i2c_adap->dev, "read %d byte%s\n", | |
554 | ret, ret == 1 ? "" : "s"); | |
1ecac07a JD |
555 | if (ret < pmsg->len) { |
556 | if (ret >= 0) | |
557 | ret = -EREMOTEIO; | |
558 | goto bailout; | |
1da177e4 LT |
559 | } |
560 | } else { | |
561 | /* write bytes from buffer */ | |
562 | ret = sendbytes(i2c_adap, pmsg); | |
494dbb64 JD |
563 | if (ret >= 1) |
564 | bit_dbg(2, &i2c_adap->dev, "wrote %d byte%s\n", | |
565 | ret, ret == 1 ? "" : "s"); | |
1ecac07a JD |
566 | if (ret < pmsg->len) { |
567 | if (ret >= 0) | |
568 | ret = -EREMOTEIO; | |
569 | goto bailout; | |
1da177e4 LT |
570 | } |
571 | } | |
572 | } | |
1ecac07a JD |
573 | ret = i; |
574 | ||
575 | bailout: | |
494dbb64 | 576 | bit_dbg(3, &i2c_adap->dev, "emitting stop condition\n"); |
1da177e4 | 577 | i2c_stop(adap); |
0a9c1475 JD |
578 | |
579 | if (adap->post_xfer) | |
580 | adap->post_xfer(i2c_adap); | |
1ecac07a | 581 | return ret; |
1da177e4 LT |
582 | } |
583 | ||
584 | static u32 bit_func(struct i2c_adapter *adap) | |
585 | { | |
cf978ab2 | 586 | return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | |
3c4bb241 JD |
587 | I2C_FUNC_SMBUS_READ_BLOCK_DATA | |
588 | I2C_FUNC_SMBUS_BLOCK_PROC_CALL | | |
1da177e4 LT |
589 | I2C_FUNC_10BIT_ADDR | I2C_FUNC_PROTOCOL_MANGLING; |
590 | } | |
591 | ||
592 | ||
593 | /* -----exported algorithm data: ------------------------------------- */ | |
594 | ||
9e11a9fb | 595 | static const struct i2c_algorithm i2c_bit_algo = { |
1da177e4 LT |
596 | .master_xfer = bit_xfer, |
597 | .functionality = bit_func, | |
598 | }; | |
599 | ||
cf978ab2 DB |
600 | /* |
601 | * registering functions to load algorithms at runtime | |
1da177e4 | 602 | */ |
0f3b4838 | 603 | static int i2c_bit_prepare_bus(struct i2c_adapter *adap) |
1da177e4 LT |
604 | { |
605 | struct i2c_algo_bit_data *bit_adap = adap->algo_data; | |
606 | ||
607 | if (bit_test) { | |
608 | int ret = test_bus(bit_adap, adap->name); | |
cf978ab2 | 609 | if (ret < 0) |
1da177e4 LT |
610 | return -ENODEV; |
611 | } | |
612 | ||
1da177e4 | 613 | /* register new adapter to i2c module... */ |
1da177e4 | 614 | adap->algo = &i2c_bit_algo; |
8fcfef6e | 615 | adap->retries = 3; |
1da177e4 | 616 | |
0f3b4838 JD |
617 | return 0; |
618 | } | |
619 | ||
620 | int i2c_bit_add_bus(struct i2c_adapter *adap) | |
621 | { | |
622 | int err; | |
623 | ||
624 | err = i2c_bit_prepare_bus(adap); | |
625 | if (err) | |
626 | return err; | |
627 | ||
b39ad0cf | 628 | return i2c_add_adapter(adap); |
1da177e4 | 629 | } |
1da177e4 | 630 | EXPORT_SYMBOL(i2c_bit_add_bus); |
1da177e4 | 631 | |
0f3b4838 JD |
632 | int i2c_bit_add_numbered_bus(struct i2c_adapter *adap) |
633 | { | |
634 | int err; | |
635 | ||
636 | err = i2c_bit_prepare_bus(adap); | |
637 | if (err) | |
638 | return err; | |
639 | ||
640 | return i2c_add_numbered_adapter(adap); | |
641 | } | |
642 | EXPORT_SYMBOL(i2c_bit_add_numbered_bus); | |
643 | ||
1da177e4 LT |
644 | MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>"); |
645 | MODULE_DESCRIPTION("I2C-Bus bit-banging algorithm"); | |
646 | MODULE_LICENSE("GPL"); |