Commit | Line | Data |
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1da177e4 LT |
1 | /* ------------------------------------------------------------------------- */ |
2 | /* i2c-algo-bit.c i2c driver algorithms for bit-shift adapters */ | |
3 | /* ------------------------------------------------------------------------- */ | |
4 | /* Copyright (C) 1995-2000 Simon G. Vogl | |
5 | ||
6 | This program is free software; you can redistribute it and/or modify | |
7 | it under the terms of the GNU General Public License as published by | |
8 | the Free Software Foundation; either version 2 of the License, or | |
9 | (at your option) any later version. | |
10 | ||
11 | This program is distributed in the hope that it will be useful, | |
12 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | GNU General Public License for more details. | |
15 | ||
16 | You should have received a copy of the GNU General Public License | |
17 | along with this program; if not, write to the Free Software | |
18 | Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ | |
19 | /* ------------------------------------------------------------------------- */ | |
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 | ||
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) | |
67 | ||
68 | static inline void sdalo(struct i2c_algo_bit_data *adap) | |
69 | { | |
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 | { | |
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 | { | |
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 | ||
94 | setscl(adap,1); | |
95 | ||
96 | /* Not all adapters have scl sense line... */ | |
7b288a01 JD |
97 | if (!adap->getscl) |
98 | goto done; | |
1da177e4 LT |
99 | |
100 | start=jiffies; | |
101 | while (! getscl(adap) ) { | |
102 | /* the hw knows how to read the clock line, | |
103 | * so we wait until it actually gets high. | |
104 | * This is safer as some chips may hold it low | |
105 | * while they are processing data internally. | |
106 | */ | |
107 | if (time_after_eq(jiffies, start+adap->timeout)) { | |
108 | return -ETIMEDOUT; | |
109 | } | |
110 | cond_resched(); | |
111 | } | |
494dbb64 JD |
112 | #ifdef DEBUG |
113 | if (jiffies != start && i2c_debug >= 3) | |
114 | pr_debug("i2c-algo-bit: needed %ld jiffies for SCL to go " | |
115 | "high\n", jiffies - start); | |
116 | #endif | |
7b288a01 JD |
117 | |
118 | done: | |
1da177e4 LT |
119 | udelay(adap->udelay); |
120 | return 0; | |
121 | } | |
122 | ||
123 | ||
124 | /* --- other auxiliary functions -------------------------------------- */ | |
125 | static void i2c_start(struct i2c_algo_bit_data *adap) | |
126 | { | |
127 | /* assert: scl, sda are high */ | |
424ed67c JD |
128 | setsda(adap, 0); |
129 | udelay(adap->udelay); | |
1da177e4 LT |
130 | scllo(adap); |
131 | } | |
132 | ||
133 | static void i2c_repstart(struct i2c_algo_bit_data *adap) | |
134 | { | |
424ed67c | 135 | /* assert: scl is low */ |
424ed67c | 136 | sdahi(adap); |
1da177e4 | 137 | sclhi(adap); |
424ed67c JD |
138 | setsda(adap, 0); |
139 | udelay(adap->udelay); | |
1da177e4 LT |
140 | scllo(adap); |
141 | } | |
142 | ||
143 | ||
144 | static void i2c_stop(struct i2c_algo_bit_data *adap) | |
145 | { | |
1da177e4 LT |
146 | /* assert: scl is low */ |
147 | sdalo(adap); | |
148 | sclhi(adap); | |
424ed67c JD |
149 | setsda(adap, 1); |
150 | udelay(adap->udelay); | |
1da177e4 LT |
151 | } |
152 | ||
153 | ||
154 | ||
155 | /* send a byte without start cond., look for arbitration, | |
156 | check ackn. from slave */ | |
157 | /* returns: | |
158 | * 1 if the device acknowledged | |
159 | * 0 if the device did not ack | |
160 | * -ETIMEDOUT if an error occurred (while raising the scl line) | |
161 | */ | |
494dbb64 | 162 | static int i2c_outb(struct i2c_adapter *i2c_adap, unsigned char c) |
1da177e4 LT |
163 | { |
164 | int i; | |
165 | int sb; | |
166 | int ack; | |
167 | struct i2c_algo_bit_data *adap = i2c_adap->algo_data; | |
168 | ||
169 | /* assert: scl is low */ | |
170 | for ( i=7 ; i>=0 ; i-- ) { | |
494dbb64 | 171 | sb = (c >> i) & 1; |
1da177e4 | 172 | setsda(adap,sb); |
424ed67c | 173 | udelay((adap->udelay + 1) / 2); |
1da177e4 | 174 | if (sclhi(adap)<0) { /* timed out */ |
494dbb64 JD |
175 | bit_dbg(1, &i2c_adap->dev, "i2c_outb: 0x%02x, " |
176 | "timeout at bit #%d\n", (int)c, i); | |
1da177e4 LT |
177 | return -ETIMEDOUT; |
178 | }; | |
179 | /* do arbitration here: | |
180 | * if ( sb && ! getsda(adap) ) -> ouch! Get out of here. | |
181 | */ | |
424ed67c | 182 | scllo(adap); |
1da177e4 LT |
183 | } |
184 | sdahi(adap); | |
185 | if (sclhi(adap)<0){ /* timeout */ | |
494dbb64 JD |
186 | bit_dbg(1, &i2c_adap->dev, "i2c_outb: 0x%02x, " |
187 | "timeout at ack\n", (int)c); | |
188 | return -ETIMEDOUT; | |
1da177e4 LT |
189 | }; |
190 | /* read ack: SDA should be pulled down by slave */ | |
494dbb64 JD |
191 | ack = !getsda(adap); /* ack: sda is pulled low -> success */ |
192 | bit_dbg(2, &i2c_adap->dev, "i2c_outb: 0x%02x %s\n", (int)c, | |
193 | ack ? "A" : "NA"); | |
1da177e4 | 194 | |
1da177e4 | 195 | scllo(adap); |
494dbb64 | 196 | return ack; |
1da177e4 LT |
197 | /* assert: scl is low (sda undef) */ |
198 | } | |
199 | ||
200 | ||
201 | static int i2c_inb(struct i2c_adapter *i2c_adap) | |
202 | { | |
203 | /* read byte via i2c port, without start/stop sequence */ | |
204 | /* acknowledge is sent in i2c_read. */ | |
205 | int i; | |
206 | unsigned char indata=0; | |
207 | struct i2c_algo_bit_data *adap = i2c_adap->algo_data; | |
208 | ||
209 | /* assert: scl is low */ | |
210 | sdahi(adap); | |
211 | for (i=0;i<8;i++) { | |
212 | if (sclhi(adap)<0) { /* timeout */ | |
494dbb64 JD |
213 | bit_dbg(1, &i2c_adap->dev, "i2c_inb: timeout at bit " |
214 | "#%d\n", 7 - i); | |
1da177e4 LT |
215 | return -ETIMEDOUT; |
216 | }; | |
217 | indata *= 2; | |
218 | if ( getsda(adap) ) | |
219 | indata |= 0x01; | |
424ed67c JD |
220 | setscl(adap, 0); |
221 | udelay(i == 7 ? adap->udelay / 2 : adap->udelay); | |
1da177e4 LT |
222 | } |
223 | /* assert: scl is low */ | |
494dbb64 | 224 | return indata; |
1da177e4 LT |
225 | } |
226 | ||
227 | /* | |
228 | * Sanity check for the adapter hardware - check the reaction of | |
229 | * the bus lines only if it seems to be idle. | |
230 | */ | |
231 | static int test_bus(struct i2c_algo_bit_data *adap, char* name) { | |
232 | int scl,sda; | |
233 | ||
234 | if (adap->getscl==NULL) | |
494dbb64 | 235 | pr_info("%s: Testing SDA only, SCL is not readable\n", name); |
1da177e4 LT |
236 | |
237 | sda=getsda(adap); | |
238 | scl=(adap->getscl==NULL?1:getscl(adap)); | |
1da177e4 | 239 | if (!scl || !sda ) { |
494dbb64 | 240 | printk(KERN_WARNING "%s: bus seems to be busy\n", name); |
1da177e4 LT |
241 | goto bailout; |
242 | } | |
243 | ||
244 | sdalo(adap); | |
245 | sda=getsda(adap); | |
246 | scl=(adap->getscl==NULL?1:getscl(adap)); | |
1da177e4 | 247 | if ( 0 != sda ) { |
494dbb64 | 248 | printk(KERN_WARNING "%s: SDA stuck high!\n", name); |
1da177e4 LT |
249 | goto bailout; |
250 | } | |
251 | if ( 0 == scl ) { | |
494dbb64 JD |
252 | printk(KERN_WARNING "%s: SCL unexpected low " |
253 | "while pulling SDA low!\n", name); | |
1da177e4 LT |
254 | goto bailout; |
255 | } | |
256 | ||
257 | sdahi(adap); | |
258 | sda=getsda(adap); | |
259 | scl=(adap->getscl==NULL?1:getscl(adap)); | |
1da177e4 | 260 | if ( 0 == sda ) { |
494dbb64 | 261 | printk(KERN_WARNING "%s: SDA stuck low!\n", name); |
1da177e4 LT |
262 | goto bailout; |
263 | } | |
264 | if ( 0 == scl ) { | |
494dbb64 JD |
265 | printk(KERN_WARNING "%s: SCL unexpected low " |
266 | "while pulling SDA high!\n", name); | |
1da177e4 LT |
267 | goto bailout; |
268 | } | |
269 | ||
270 | scllo(adap); | |
271 | sda=getsda(adap); | |
272 | scl=(adap->getscl==NULL?0:getscl(adap)); | |
1da177e4 | 273 | if ( 0 != scl ) { |
494dbb64 | 274 | printk(KERN_WARNING "%s: SCL stuck high!\n", name); |
1da177e4 LT |
275 | goto bailout; |
276 | } | |
277 | if ( 0 == sda ) { | |
494dbb64 JD |
278 | printk(KERN_WARNING "%s: SDA unexpected low " |
279 | "while pulling SCL low!\n", name); | |
1da177e4 LT |
280 | goto bailout; |
281 | } | |
282 | ||
283 | sclhi(adap); | |
284 | sda=getsda(adap); | |
285 | scl=(adap->getscl==NULL?1:getscl(adap)); | |
1da177e4 | 286 | if ( 0 == scl ) { |
494dbb64 | 287 | printk(KERN_WARNING "%s: SCL stuck low!\n", name); |
1da177e4 LT |
288 | goto bailout; |
289 | } | |
290 | if ( 0 == sda ) { | |
494dbb64 JD |
291 | printk(KERN_WARNING "%s: SDA unexpected low " |
292 | "while pulling SCL high!\n", name); | |
1da177e4 LT |
293 | goto bailout; |
294 | } | |
494dbb64 | 295 | pr_info("%s: Test OK\n", name); |
1da177e4 LT |
296 | return 0; |
297 | bailout: | |
298 | sdahi(adap); | |
299 | sclhi(adap); | |
300 | return -ENODEV; | |
301 | } | |
302 | ||
303 | /* ----- Utility functions | |
304 | */ | |
305 | ||
306 | /* try_address tries to contact a chip for a number of | |
307 | * times before it gives up. | |
308 | * return values: | |
309 | * 1 chip answered | |
310 | * 0 chip did not answer | |
311 | * -x transmission error | |
312 | */ | |
7b288a01 | 313 | static int try_address(struct i2c_adapter *i2c_adap, |
1da177e4 LT |
314 | unsigned char addr, int retries) |
315 | { | |
316 | struct i2c_algo_bit_data *adap = i2c_adap->algo_data; | |
317 | int i,ret = -1; | |
318 | for (i=0;i<=retries;i++) { | |
319 | ret = i2c_outb(i2c_adap,addr); | |
1ecac07a JD |
320 | if (ret == 1 || i == retries) |
321 | break; | |
494dbb64 | 322 | bit_dbg(3, &i2c_adap->dev, "emitting stop condition\n"); |
1da177e4 | 323 | i2c_stop(adap); |
1da177e4 | 324 | udelay(adap->udelay); |
424ed67c | 325 | yield(); |
494dbb64 | 326 | bit_dbg(3, &i2c_adap->dev, "emitting start condition\n"); |
424ed67c | 327 | i2c_start(adap); |
1da177e4 | 328 | } |
494dbb64 JD |
329 | if (i && ret) |
330 | bit_dbg(1, &i2c_adap->dev, "Used %d tries to %s client at " | |
331 | "0x%02x: %s\n", i + 1, | |
332 | addr & 1 ? "read from" : "write to", addr >> 1, | |
333 | ret == 1 ? "success" : "failed, timeout?"); | |
1da177e4 LT |
334 | return ret; |
335 | } | |
336 | ||
337 | static int sendbytes(struct i2c_adapter *i2c_adap, struct i2c_msg *msg) | |
338 | { | |
494dbb64 | 339 | const unsigned char *temp = msg->buf; |
1da177e4 LT |
340 | int count = msg->len; |
341 | unsigned short nak_ok = msg->flags & I2C_M_IGNORE_NAK; | |
342 | int retval; | |
343 | int wrcount=0; | |
344 | ||
345 | while (count > 0) { | |
494dbb64 | 346 | retval = i2c_outb(i2c_adap, *temp); |
1da177e4 LT |
347 | if ((retval>0) || (nak_ok && (retval==0))) { /* ok or ignored NAK */ |
348 | count--; | |
349 | temp++; | |
350 | wrcount++; | |
351 | } else { /* arbitration or no acknowledge */ | |
352 | dev_err(&i2c_adap->dev, "sendbytes: error - bailout.\n"); | |
1da177e4 LT |
353 | return (retval<0)? retval : -EFAULT; |
354 | /* got a better one ?? */ | |
355 | } | |
1da177e4 LT |
356 | } |
357 | return wrcount; | |
358 | } | |
359 | ||
939bc494 DB |
360 | static int acknak(struct i2c_adapter *i2c_adap, int is_ack) |
361 | { | |
362 | struct i2c_algo_bit_data *adap = i2c_adap->algo_data; | |
363 | ||
364 | /* assert: sda is high */ | |
365 | if (is_ack) /* send ack */ | |
366 | setsda(adap, 0); | |
367 | udelay((adap->udelay + 1) / 2); | |
368 | if (sclhi(adap) < 0) { /* timeout */ | |
369 | dev_err(&i2c_adap->dev, "readbytes: ack/nak timeout\n"); | |
370 | return -ETIMEDOUT; | |
371 | } | |
372 | scllo(adap); | |
373 | return 0; | |
374 | } | |
375 | ||
7b288a01 | 376 | static int readbytes(struct i2c_adapter *i2c_adap, struct i2c_msg *msg) |
1da177e4 LT |
377 | { |
378 | int inval; | |
379 | int rdcount=0; /* counts bytes read */ | |
494dbb64 | 380 | unsigned char *temp = msg->buf; |
1da177e4 | 381 | int count = msg->len; |
939bc494 | 382 | const unsigned flags = msg->flags; |
1da177e4 LT |
383 | |
384 | while (count > 0) { | |
385 | inval = i2c_inb(i2c_adap); | |
1da177e4 LT |
386 | if (inval>=0) { |
387 | *temp = inval; | |
388 | rdcount++; | |
389 | } else { /* read timed out */ | |
1da177e4 LT |
390 | break; |
391 | } | |
392 | ||
393 | temp++; | |
394 | count--; | |
395 | ||
3c4bb241 JD |
396 | /* Some SMBus transactions require that we receive the |
397 | transaction length as the first read byte. */ | |
939bc494 | 398 | if (rdcount == 1 && (flags & I2C_M_RECV_LEN)) { |
3c4bb241 | 399 | if (inval <= 0 || inval > I2C_SMBUS_BLOCK_MAX) { |
939bc494 DB |
400 | if (!(flags & I2C_M_NO_RD_ACK)) |
401 | acknak(i2c_adap, 0); | |
494dbb64 JD |
402 | dev_err(&i2c_adap->dev, "readbytes: invalid " |
403 | "block length (%d)\n", inval); | |
3c4bb241 JD |
404 | return -EREMOTEIO; |
405 | } | |
406 | /* The original count value accounts for the extra | |
407 | bytes, that is, either 1 for a regular transaction, | |
408 | or 2 for a PEC transaction. */ | |
409 | count += inval; | |
410 | msg->len += inval; | |
411 | } | |
939bc494 DB |
412 | |
413 | bit_dbg(2, &i2c_adap->dev, "readbytes: 0x%02x %s\n", | |
414 | inval, | |
415 | (flags & I2C_M_NO_RD_ACK) | |
416 | ? "(no ack/nak)" | |
417 | : (count ? "A" : "NA")); | |
418 | ||
419 | if (!(flags & I2C_M_NO_RD_ACK)) { | |
420 | inval = acknak(i2c_adap, count); | |
421 | if (inval < 0) | |
422 | return inval; | |
423 | } | |
1da177e4 LT |
424 | } |
425 | return rdcount; | |
426 | } | |
427 | ||
428 | /* doAddress initiates the transfer by generating the start condition (in | |
429 | * try_address) and transmits the address in the necessary format to handle | |
430 | * reads, writes as well as 10bit-addresses. | |
431 | * returns: | |
432 | * 0 everything went okay, the chip ack'ed, or IGNORE_NAK flag was set | |
433 | * -x an error occurred (like: -EREMOTEIO if the device did not answer, or | |
434 | * -ETIMEDOUT, for example if the lines are stuck...) | |
435 | */ | |
7b288a01 | 436 | static int bit_doAddress(struct i2c_adapter *i2c_adap, struct i2c_msg *msg) |
1da177e4 LT |
437 | { |
438 | unsigned short flags = msg->flags; | |
439 | unsigned short nak_ok = msg->flags & I2C_M_IGNORE_NAK; | |
440 | struct i2c_algo_bit_data *adap = i2c_adap->algo_data; | |
441 | ||
442 | unsigned char addr; | |
443 | int ret, retries; | |
444 | ||
445 | retries = nak_ok ? 0 : i2c_adap->retries; | |
446 | ||
447 | if ( (flags & I2C_M_TEN) ) { | |
448 | /* a ten bit address */ | |
449 | addr = 0xf0 | (( msg->addr >> 7) & 0x03); | |
494dbb64 | 450 | bit_dbg(2, &i2c_adap->dev, "addr0: %d\n", addr); |
1da177e4 LT |
451 | /* try extended address code...*/ |
452 | ret = try_address(i2c_adap, addr, retries); | |
453 | if ((ret != 1) && !nak_ok) { | |
494dbb64 JD |
454 | dev_err(&i2c_adap->dev, |
455 | "died at extended address code\n"); | |
1da177e4 LT |
456 | return -EREMOTEIO; |
457 | } | |
458 | /* the remaining 8 bit address */ | |
459 | ret = i2c_outb(i2c_adap,msg->addr & 0x7f); | |
460 | if ((ret != 1) && !nak_ok) { | |
461 | /* the chip did not ack / xmission error occurred */ | |
494dbb64 | 462 | dev_err(&i2c_adap->dev, "died at 2nd address code\n"); |
1da177e4 LT |
463 | return -EREMOTEIO; |
464 | } | |
465 | if ( flags & I2C_M_RD ) { | |
494dbb64 JD |
466 | bit_dbg(3, &i2c_adap->dev, "emitting repeated " |
467 | "start condition\n"); | |
1da177e4 LT |
468 | i2c_repstart(adap); |
469 | /* okay, now switch into reading mode */ | |
470 | addr |= 0x01; | |
471 | ret = try_address(i2c_adap, addr, retries); | |
472 | if ((ret!=1) && !nak_ok) { | |
494dbb64 JD |
473 | dev_err(&i2c_adap->dev, |
474 | "died at repeated address code\n"); | |
1da177e4 LT |
475 | return -EREMOTEIO; |
476 | } | |
477 | } | |
478 | } else { /* normal 7bit address */ | |
479 | addr = ( msg->addr << 1 ); | |
480 | if (flags & I2C_M_RD ) | |
481 | addr |= 1; | |
482 | if (flags & I2C_M_REV_DIR_ADDR ) | |
483 | addr ^= 1; | |
484 | ret = try_address(i2c_adap, addr, retries); | |
485 | if ((ret!=1) && !nak_ok) | |
486 | return -EREMOTEIO; | |
487 | } | |
488 | ||
489 | return 0; | |
490 | } | |
491 | ||
492 | static int bit_xfer(struct i2c_adapter *i2c_adap, | |
493 | struct i2c_msg msgs[], int num) | |
494 | { | |
495 | struct i2c_msg *pmsg; | |
496 | struct i2c_algo_bit_data *adap = i2c_adap->algo_data; | |
497 | ||
498 | int i,ret; | |
499 | unsigned short nak_ok; | |
500 | ||
494dbb64 | 501 | bit_dbg(3, &i2c_adap->dev, "emitting start condition\n"); |
1da177e4 LT |
502 | i2c_start(adap); |
503 | for (i=0;i<num;i++) { | |
504 | pmsg = &msgs[i]; | |
505 | nak_ok = pmsg->flags & I2C_M_IGNORE_NAK; | |
506 | if (!(pmsg->flags & I2C_M_NOSTART)) { | |
507 | if (i) { | |
494dbb64 JD |
508 | bit_dbg(3, &i2c_adap->dev, "emitting " |
509 | "repeated start condition\n"); | |
1da177e4 LT |
510 | i2c_repstart(adap); |
511 | } | |
512 | ret = bit_doAddress(i2c_adap, pmsg); | |
513 | if ((ret != 0) && !nak_ok) { | |
494dbb64 JD |
514 | bit_dbg(1, &i2c_adap->dev, "NAK from " |
515 | "device addr 0x%02x msg #%d\n", | |
516 | msgs[i].addr, i); | |
1ecac07a | 517 | goto bailout; |
1da177e4 LT |
518 | } |
519 | } | |
520 | if (pmsg->flags & I2C_M_RD ) { | |
521 | /* read bytes into buffer*/ | |
522 | ret = readbytes(i2c_adap, pmsg); | |
494dbb64 JD |
523 | if (ret >= 1) |
524 | bit_dbg(2, &i2c_adap->dev, "read %d byte%s\n", | |
525 | ret, ret == 1 ? "" : "s"); | |
1ecac07a JD |
526 | if (ret < pmsg->len) { |
527 | if (ret >= 0) | |
528 | ret = -EREMOTEIO; | |
529 | goto bailout; | |
1da177e4 LT |
530 | } |
531 | } else { | |
532 | /* write bytes from buffer */ | |
533 | ret = sendbytes(i2c_adap, pmsg); | |
494dbb64 JD |
534 | if (ret >= 1) |
535 | bit_dbg(2, &i2c_adap->dev, "wrote %d byte%s\n", | |
536 | ret, ret == 1 ? "" : "s"); | |
1ecac07a JD |
537 | if (ret < pmsg->len) { |
538 | if (ret >= 0) | |
539 | ret = -EREMOTEIO; | |
540 | goto bailout; | |
1da177e4 LT |
541 | } |
542 | } | |
543 | } | |
1ecac07a JD |
544 | ret = i; |
545 | ||
546 | bailout: | |
494dbb64 | 547 | bit_dbg(3, &i2c_adap->dev, "emitting stop condition\n"); |
1da177e4 | 548 | i2c_stop(adap); |
1ecac07a | 549 | return ret; |
1da177e4 LT |
550 | } |
551 | ||
552 | static u32 bit_func(struct i2c_adapter *adap) | |
553 | { | |
554 | return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | | |
3c4bb241 JD |
555 | I2C_FUNC_SMBUS_READ_BLOCK_DATA | |
556 | I2C_FUNC_SMBUS_BLOCK_PROC_CALL | | |
1da177e4 LT |
557 | I2C_FUNC_10BIT_ADDR | I2C_FUNC_PROTOCOL_MANGLING; |
558 | } | |
559 | ||
560 | ||
561 | /* -----exported algorithm data: ------------------------------------- */ | |
562 | ||
9e11a9fb | 563 | static const struct i2c_algorithm i2c_bit_algo = { |
1da177e4 LT |
564 | .master_xfer = bit_xfer, |
565 | .functionality = bit_func, | |
566 | }; | |
567 | ||
568 | /* | |
569 | * registering functions to load algorithms at runtime | |
570 | */ | |
0f3b4838 | 571 | static int i2c_bit_prepare_bus(struct i2c_adapter *adap) |
1da177e4 LT |
572 | { |
573 | struct i2c_algo_bit_data *bit_adap = adap->algo_data; | |
574 | ||
575 | if (bit_test) { | |
576 | int ret = test_bus(bit_adap, adap->name); | |
577 | if (ret<0) | |
578 | return -ENODEV; | |
579 | } | |
580 | ||
1da177e4 | 581 | /* register new adapter to i2c module... */ |
1da177e4 LT |
582 | adap->algo = &i2c_bit_algo; |
583 | ||
584 | adap->timeout = 100; /* default values, should */ | |
585 | adap->retries = 3; /* be replaced by defines */ | |
586 | ||
0f3b4838 JD |
587 | return 0; |
588 | } | |
589 | ||
590 | int i2c_bit_add_bus(struct i2c_adapter *adap) | |
591 | { | |
592 | int err; | |
593 | ||
594 | err = i2c_bit_prepare_bus(adap); | |
595 | if (err) | |
596 | return err; | |
597 | ||
b39ad0cf | 598 | return i2c_add_adapter(adap); |
1da177e4 | 599 | } |
1da177e4 | 600 | EXPORT_SYMBOL(i2c_bit_add_bus); |
1da177e4 | 601 | |
0f3b4838 JD |
602 | int i2c_bit_add_numbered_bus(struct i2c_adapter *adap) |
603 | { | |
604 | int err; | |
605 | ||
606 | err = i2c_bit_prepare_bus(adap); | |
607 | if (err) | |
608 | return err; | |
609 | ||
610 | return i2c_add_numbered_adapter(adap); | |
611 | } | |
612 | EXPORT_SYMBOL(i2c_bit_add_numbered_bus); | |
613 | ||
1da177e4 LT |
614 | MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>"); |
615 | MODULE_DESCRIPTION("I2C-Bus bit-banging algorithm"); | |
616 | MODULE_LICENSE("GPL"); |