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1da177e4 LT |
1 | /* ------------------------------------------------------------------------- */ |
2 | /* i2c-algo-pcf.c i2c driver algorithms for PCF8584 adapters */ | |
3 | /* ------------------------------------------------------------------------- */ | |
4 | /* Copyright (C) 1995-1997 Simon G. Vogl | |
5 | 1998-2000 Hans Berglund | |
6 | ||
7 | This program is free software; you can redistribute it and/or modify | |
8 | it under the terms of the GNU General Public License as published by | |
9 | the Free Software Foundation; either version 2 of the License, or | |
10 | (at your option) any later version. | |
11 | ||
12 | This program is distributed in the hope that it will be useful, | |
13 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | GNU General Public License for more details. | |
16 | ||
17 | You should have received a copy of the GNU General Public License | |
18 | along with this program; if not, write to the Free Software | |
19 | Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ | |
20 | /* ------------------------------------------------------------------------- */ | |
21 | ||
96de0e25 | 22 | /* With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi> and |
1da177e4 LT |
23 | Frodo Looijaard <frodol@dds.nl> ,and also from Martin Bailey |
24 | <mbailey@littlefeet-inc.com> */ | |
25 | ||
26 | /* Partially rewriten by Oleg I. Vdovikin <vdovikin@jscc.ru> to handle multiple | |
27 | messages, proper stop/repstart signaling during receive, | |
28 | added detect code */ | |
29 | ||
30 | #include <linux/kernel.h> | |
31 | #include <linux/module.h> | |
32 | #include <linux/delay.h> | |
33 | #include <linux/slab.h> | |
34 | #include <linux/init.h> | |
35 | #include <linux/errno.h> | |
36 | #include <linux/i2c.h> | |
37 | #include <linux/i2c-algo-pcf.h> | |
38 | #include "i2c-algo-pcf.h" | |
39 | ||
40 | ||
41 | #define DEB2(x) if (i2c_debug>=2) x | |
42 | #define DEB3(x) if (i2c_debug>=3) x /* print several statistical values*/ | |
43 | #define DEBPROTO(x) if (i2c_debug>=9) x; | |
44 | /* debug the protocol by showing transferred bits */ | |
45 | #define DEF_TIMEOUT 16 | |
46 | ||
47 | /* module parameters: | |
48 | */ | |
49 | static int i2c_debug; | |
50 | ||
51 | /* --- setting states on the bus with the right timing: --------------- */ | |
52 | ||
53 | #define set_pcf(adap, ctl, val) adap->setpcf(adap->data, ctl, val) | |
54 | #define get_pcf(adap, ctl) adap->getpcf(adap->data, ctl) | |
55 | #define get_own(adap) adap->getown(adap->data) | |
56 | #define get_clock(adap) adap->getclock(adap->data) | |
57 | #define i2c_outb(adap, val) adap->setpcf(adap->data, 0, val) | |
58 | #define i2c_inb(adap) adap->getpcf(adap->data, 0) | |
59 | ||
60 | /* --- other auxiliary functions -------------------------------------- */ | |
61 | ||
62 | static void i2c_start(struct i2c_algo_pcf_data *adap) | |
63 | { | |
64 | DEBPROTO(printk("S ")); | |
65 | set_pcf(adap, 1, I2C_PCF_START); | |
66 | } | |
67 | ||
68 | static void i2c_repstart(struct i2c_algo_pcf_data *adap) | |
69 | { | |
70 | DEBPROTO(printk(" Sr ")); | |
71 | set_pcf(adap, 1, I2C_PCF_REPSTART); | |
72 | } | |
73 | ||
74 | ||
75 | static void i2c_stop(struct i2c_algo_pcf_data *adap) | |
76 | { | |
77 | DEBPROTO(printk("P\n")); | |
78 | set_pcf(adap, 1, I2C_PCF_STOP); | |
79 | } | |
80 | ||
81 | static int wait_for_bb(struct i2c_algo_pcf_data *adap) { | |
82 | ||
83 | int timeout = DEF_TIMEOUT; | |
84 | int status; | |
85 | ||
86 | status = get_pcf(adap, 1); | |
87 | #ifndef STUB_I2C | |
88 | while (timeout-- && !(status & I2C_PCF_BB)) { | |
89 | udelay(100); /* wait for 100 us */ | |
90 | status = get_pcf(adap, 1); | |
91 | } | |
92 | #endif | |
93 | if (timeout <= 0) { | |
94 | printk(KERN_ERR "Timeout waiting for Bus Busy\n"); | |
95 | } | |
96 | ||
97 | return (timeout<=0); | |
98 | } | |
99 | ||
100 | ||
101 | static int wait_for_pin(struct i2c_algo_pcf_data *adap, int *status) { | |
102 | ||
103 | int timeout = DEF_TIMEOUT; | |
104 | ||
105 | *status = get_pcf(adap, 1); | |
106 | #ifndef STUB_I2C | |
107 | while (timeout-- && (*status & I2C_PCF_PIN)) { | |
108 | adap->waitforpin(); | |
109 | *status = get_pcf(adap, 1); | |
110 | } | |
111 | if (*status & I2C_PCF_LAB) { | |
112 | DEB2(printk(KERN_INFO | |
113 | "i2c-algo-pcf.o: lost arbitration (CSR 0x%02x)\n", | |
114 | *status)); | |
115 | /* Cleanup from LAB-- reset and enable ESO. | |
116 | * This resets the PCF8584; since we've lost the bus, no | |
117 | * further attempts should be made by callers to clean up | |
118 | * (no i2c_stop() etc.) | |
119 | */ | |
120 | set_pcf(adap, 1, I2C_PCF_PIN); | |
121 | set_pcf(adap, 1, I2C_PCF_ESO); | |
122 | /* TODO: we should pause for a time period sufficient for any | |
123 | * running I2C transaction to complete-- the arbitration | |
124 | * logic won't work properly until the next START is seen. | |
125 | */ | |
126 | DEB2(printk(KERN_INFO | |
127 | "i2c-algo-pcf.o: reset LAB condition (CSR 0x%02x)\n", | |
128 | get_pcf(adap,1))); | |
129 | return(-EINTR); | |
130 | } | |
131 | #endif | |
132 | if (timeout <= 0) | |
133 | return(-1); | |
134 | else | |
135 | return(0); | |
136 | } | |
137 | ||
138 | /* | |
139 | * This should perform the 'PCF8584 initialization sequence' as described | |
140 | * in the Philips IC12 data book (1995, Aug 29). | |
141 | * There should be a 30 clock cycle wait after reset, I assume this | |
142 | * has been fulfilled. | |
143 | * There should be a delay at the end equal to the longest I2C message | |
144 | * to synchronize the BB-bit (in multimaster systems). How long is | |
145 | * this? I assume 1 second is always long enough. | |
146 | * | |
147 | * vdovikin: added detect code for PCF8584 | |
148 | */ | |
149 | static int pcf_init_8584 (struct i2c_algo_pcf_data *adap) | |
150 | { | |
151 | unsigned char temp; | |
152 | ||
153 | DEB3(printk(KERN_DEBUG "i2c-algo-pcf.o: PCF state 0x%02x\n", get_pcf(adap, 1))); | |
154 | ||
155 | /* S1=0x80: S0 selected, serial interface off */ | |
156 | set_pcf(adap, 1, I2C_PCF_PIN); | |
157 | /* check to see S1 now used as R/W ctrl - | |
158 | PCF8584 does that when ESO is zero */ | |
159 | if (((temp = get_pcf(adap, 1)) & 0x7f) != (0)) { | |
160 | DEB2(printk(KERN_ERR "i2c-algo-pcf.o: PCF detection failed -- can't select S0 (0x%02x).\n", temp)); | |
161 | return -ENXIO; /* definetly not PCF8584 */ | |
162 | } | |
163 | ||
164 | /* load own address in S0, effective address is (own << 1) */ | |
165 | i2c_outb(adap, get_own(adap)); | |
166 | /* check it's really written */ | |
167 | if ((temp = i2c_inb(adap)) != get_own(adap)) { | |
168 | DEB2(printk(KERN_ERR "i2c-algo-pcf.o: PCF detection failed -- can't set S0 (0x%02x).\n", temp)); | |
169 | return -ENXIO; | |
170 | } | |
171 | ||
172 | /* S1=0xA0, next byte in S2 */ | |
173 | set_pcf(adap, 1, I2C_PCF_PIN | I2C_PCF_ES1); | |
174 | /* check to see S2 now selected */ | |
175 | if (((temp = get_pcf(adap, 1)) & 0x7f) != I2C_PCF_ES1) { | |
176 | DEB2(printk(KERN_ERR "i2c-algo-pcf.o: PCF detection failed -- can't select S2 (0x%02x).\n", temp)); | |
177 | return -ENXIO; | |
178 | } | |
179 | ||
180 | /* load clock register S2 */ | |
181 | i2c_outb(adap, get_clock(adap)); | |
182 | /* check it's really written, the only 5 lowest bits does matter */ | |
183 | if (((temp = i2c_inb(adap)) & 0x1f) != get_clock(adap)) { | |
184 | DEB2(printk(KERN_ERR "i2c-algo-pcf.o: PCF detection failed -- can't set S2 (0x%02x).\n", temp)); | |
185 | return -ENXIO; | |
186 | } | |
187 | ||
188 | /* Enable serial interface, idle, S0 selected */ | |
189 | set_pcf(adap, 1, I2C_PCF_IDLE); | |
190 | ||
191 | /* check to see PCF is really idled and we can access status register */ | |
192 | if ((temp = get_pcf(adap, 1)) != (I2C_PCF_PIN | I2C_PCF_BB)) { | |
193 | DEB2(printk(KERN_ERR "i2c-algo-pcf.o: PCF detection failed -- can't select S1` (0x%02x).\n", temp)); | |
194 | return -ENXIO; | |
195 | } | |
196 | ||
197 | printk(KERN_DEBUG "i2c-algo-pcf.o: deteted and initialized PCF8584.\n"); | |
198 | ||
199 | return 0; | |
200 | } | |
201 | ||
202 | ||
203 | /* ----- Utility functions | |
204 | */ | |
205 | ||
206 | static inline int try_address(struct i2c_algo_pcf_data *adap, | |
207 | unsigned char addr, int retries) | |
208 | { | |
209 | int i, status, ret = -1; | |
210 | int wfp; | |
211 | for (i=0;i<retries;i++) { | |
212 | i2c_outb(adap, addr); | |
213 | i2c_start(adap); | |
214 | status = get_pcf(adap, 1); | |
215 | if ((wfp = wait_for_pin(adap, &status)) >= 0) { | |
216 | if ((status & I2C_PCF_LRB) == 0) { | |
217 | i2c_stop(adap); | |
218 | break; /* success! */ | |
219 | } | |
220 | } | |
221 | if (wfp == -EINTR) { | |
222 | /* arbitration lost */ | |
223 | udelay(adap->udelay); | |
224 | return -EINTR; | |
225 | } | |
226 | i2c_stop(adap); | |
227 | udelay(adap->udelay); | |
228 | } | |
229 | DEB2(if (i) printk(KERN_DEBUG "i2c-algo-pcf.o: needed %d retries for %d\n",i, | |
230 | addr)); | |
231 | return ret; | |
232 | } | |
233 | ||
234 | ||
235 | static int pcf_sendbytes(struct i2c_adapter *i2c_adap, const char *buf, | |
236 | int count, int last) | |
237 | { | |
238 | struct i2c_algo_pcf_data *adap = i2c_adap->algo_data; | |
239 | int wrcount, status, timeout; | |
240 | ||
241 | for (wrcount=0; wrcount<count; ++wrcount) { | |
242 | DEB2(dev_dbg(&i2c_adap->dev, "i2c_write: writing %2.2X\n", | |
243 | buf[wrcount]&0xff)); | |
244 | i2c_outb(adap, buf[wrcount]); | |
245 | timeout = wait_for_pin(adap, &status); | |
246 | if (timeout) { | |
247 | if (timeout == -EINTR) { | |
248 | /* arbitration lost */ | |
249 | return -EINTR; | |
250 | } | |
251 | i2c_stop(adap); | |
252 | dev_err(&i2c_adap->dev, "i2c_write: error - timeout.\n"); | |
253 | return -EREMOTEIO; /* got a better one ?? */ | |
254 | } | |
255 | #ifndef STUB_I2C | |
256 | if (status & I2C_PCF_LRB) { | |
257 | i2c_stop(adap); | |
258 | dev_err(&i2c_adap->dev, "i2c_write: error - no ack.\n"); | |
259 | return -EREMOTEIO; /* got a better one ?? */ | |
260 | } | |
261 | #endif | |
262 | } | |
263 | if (last) { | |
264 | i2c_stop(adap); | |
265 | } | |
266 | else { | |
267 | i2c_repstart(adap); | |
268 | } | |
269 | ||
270 | return (wrcount); | |
271 | } | |
272 | ||
273 | ||
274 | static int pcf_readbytes(struct i2c_adapter *i2c_adap, char *buf, | |
275 | int count, int last) | |
276 | { | |
277 | int i, status; | |
278 | struct i2c_algo_pcf_data *adap = i2c_adap->algo_data; | |
279 | int wfp; | |
280 | ||
281 | /* increment number of bytes to read by one -- read dummy byte */ | |
282 | for (i = 0; i <= count; i++) { | |
283 | ||
284 | if ((wfp = wait_for_pin(adap, &status))) { | |
285 | if (wfp == -EINTR) { | |
286 | /* arbitration lost */ | |
287 | return -EINTR; | |
288 | } | |
289 | i2c_stop(adap); | |
290 | dev_err(&i2c_adap->dev, "pcf_readbytes timed out.\n"); | |
291 | return (-1); | |
292 | } | |
293 | ||
294 | #ifndef STUB_I2C | |
295 | if ((status & I2C_PCF_LRB) && (i != count)) { | |
296 | i2c_stop(adap); | |
297 | dev_err(&i2c_adap->dev, "i2c_read: i2c_inb, No ack.\n"); | |
298 | return (-1); | |
299 | } | |
300 | #endif | |
301 | ||
302 | if (i == count - 1) { | |
303 | set_pcf(adap, 1, I2C_PCF_ESO); | |
304 | } else | |
305 | if (i == count) { | |
306 | if (last) { | |
307 | i2c_stop(adap); | |
308 | } else { | |
309 | i2c_repstart(adap); | |
310 | } | |
311 | }; | |
312 | ||
313 | if (i) { | |
314 | buf[i - 1] = i2c_inb(adap); | |
315 | } else { | |
316 | i2c_inb(adap); /* dummy read */ | |
317 | } | |
318 | } | |
319 | ||
320 | return (i - 1); | |
321 | } | |
322 | ||
323 | ||
324 | static inline int pcf_doAddress(struct i2c_algo_pcf_data *adap, | |
325 | struct i2c_msg *msg, int retries) | |
326 | { | |
327 | unsigned short flags = msg->flags; | |
328 | unsigned char addr; | |
329 | int ret; | |
330 | if ( (flags & I2C_M_TEN) ) { | |
331 | /* a ten bit address */ | |
332 | addr = 0xf0 | (( msg->addr >> 7) & 0x03); | |
333 | DEB2(printk(KERN_DEBUG "addr0: %d\n",addr)); | |
334 | /* try extended address code...*/ | |
335 | ret = try_address(adap, addr, retries); | |
336 | if (ret!=1) { | |
337 | printk(KERN_ERR "died at extended address code.\n"); | |
338 | return -EREMOTEIO; | |
339 | } | |
340 | /* the remaining 8 bit address */ | |
341 | i2c_outb(adap,msg->addr & 0x7f); | |
342 | /* Status check comes here */ | |
343 | if (ret != 1) { | |
344 | printk(KERN_ERR "died at 2nd address code.\n"); | |
345 | return -EREMOTEIO; | |
346 | } | |
347 | if ( flags & I2C_M_RD ) { | |
348 | i2c_repstart(adap); | |
349 | /* okay, now switch into reading mode */ | |
350 | addr |= 0x01; | |
351 | ret = try_address(adap, addr, retries); | |
352 | if (ret!=1) { | |
353 | printk(KERN_ERR "died at extended address code.\n"); | |
354 | return -EREMOTEIO; | |
355 | } | |
356 | } | |
357 | } else { /* normal 7bit address */ | |
358 | addr = ( msg->addr << 1 ); | |
359 | if (flags & I2C_M_RD ) | |
360 | addr |= 1; | |
361 | if (flags & I2C_M_REV_DIR_ADDR ) | |
362 | addr ^= 1; | |
363 | i2c_outb(adap, addr); | |
364 | } | |
365 | return 0; | |
366 | } | |
367 | ||
368 | static int pcf_xfer(struct i2c_adapter *i2c_adap, | |
369 | struct i2c_msg *msgs, | |
370 | int num) | |
371 | { | |
372 | struct i2c_algo_pcf_data *adap = i2c_adap->algo_data; | |
373 | struct i2c_msg *pmsg; | |
374 | int i; | |
375 | int ret=0, timeout, status; | |
376 | ||
377 | ||
378 | /* Check for bus busy */ | |
379 | timeout = wait_for_bb(adap); | |
380 | if (timeout) { | |
381 | DEB2(printk(KERN_ERR "i2c-algo-pcf.o: " | |
382 | "Timeout waiting for BB in pcf_xfer\n");) | |
383 | return -EIO; | |
384 | } | |
385 | ||
386 | for (i = 0;ret >= 0 && i < num; i++) { | |
387 | pmsg = &msgs[i]; | |
388 | ||
389 | DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: Doing %s %d bytes to 0x%02x - %d of %d messages\n", | |
390 | pmsg->flags & I2C_M_RD ? "read" : "write", | |
391 | pmsg->len, pmsg->addr, i + 1, num);) | |
392 | ||
393 | ret = pcf_doAddress(adap, pmsg, i2c_adap->retries); | |
394 | ||
395 | /* Send START */ | |
396 | if (i == 0) { | |
397 | i2c_start(adap); | |
398 | } | |
399 | ||
400 | /* Wait for PIN (pending interrupt NOT) */ | |
401 | timeout = wait_for_pin(adap, &status); | |
402 | if (timeout) { | |
403 | if (timeout == -EINTR) { | |
404 | /* arbitration lost */ | |
405 | return (-EINTR); | |
406 | } | |
407 | i2c_stop(adap); | |
408 | DEB2(printk(KERN_ERR "i2c-algo-pcf.o: Timeout waiting " | |
409 | "for PIN(1) in pcf_xfer\n");) | |
410 | return (-EREMOTEIO); | |
411 | } | |
412 | ||
413 | #ifndef STUB_I2C | |
414 | /* Check LRB (last rcvd bit - slave ack) */ | |
415 | if (status & I2C_PCF_LRB) { | |
416 | i2c_stop(adap); | |
417 | DEB2(printk(KERN_ERR "i2c-algo-pcf.o: No LRB(1) in pcf_xfer\n");) | |
418 | return (-EREMOTEIO); | |
419 | } | |
420 | #endif | |
421 | ||
422 | DEB3(printk(KERN_DEBUG "i2c-algo-pcf.o: Msg %d, addr=0x%x, flags=0x%x, len=%d\n", | |
423 | i, msgs[i].addr, msgs[i].flags, msgs[i].len);) | |
424 | ||
425 | /* Read */ | |
426 | if (pmsg->flags & I2C_M_RD) { | |
427 | /* read bytes into buffer*/ | |
428 | ret = pcf_readbytes(i2c_adap, pmsg->buf, pmsg->len, | |
429 | (i + 1 == num)); | |
430 | ||
431 | if (ret != pmsg->len) { | |
432 | DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: fail: " | |
433 | "only read %d bytes.\n",ret)); | |
434 | } else { | |
435 | DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: read %d bytes.\n",ret)); | |
436 | } | |
437 | } else { /* Write */ | |
438 | ret = pcf_sendbytes(i2c_adap, pmsg->buf, pmsg->len, | |
439 | (i + 1 == num)); | |
440 | ||
441 | if (ret != pmsg->len) { | |
442 | DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: fail: " | |
443 | "only wrote %d bytes.\n",ret)); | |
444 | } else { | |
445 | DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: wrote %d bytes.\n",ret)); | |
446 | } | |
447 | } | |
448 | } | |
449 | ||
450 | return (i); | |
451 | } | |
452 | ||
453 | static u32 pcf_func(struct i2c_adapter *adap) | |
454 | { | |
455 | return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | | |
456 | I2C_FUNC_10BIT_ADDR | I2C_FUNC_PROTOCOL_MANGLING; | |
457 | } | |
458 | ||
459 | /* -----exported algorithm data: ------------------------------------- */ | |
460 | ||
9e11a9fb | 461 | static const struct i2c_algorithm pcf_algo = { |
1da177e4 LT |
462 | .master_xfer = pcf_xfer, |
463 | .functionality = pcf_func, | |
464 | }; | |
465 | ||
466 | /* | |
467 | * registering functions to load algorithms at runtime | |
468 | */ | |
469 | int i2c_pcf_add_bus(struct i2c_adapter *adap) | |
470 | { | |
471 | struct i2c_algo_pcf_data *pcf_adap = adap->algo_data; | |
472 | int rval; | |
473 | ||
474 | DEB2(dev_dbg(&adap->dev, "hw routines registered.\n")); | |
475 | ||
476 | /* register new adapter to i2c module... */ | |
1da177e4 LT |
477 | adap->algo = &pcf_algo; |
478 | ||
479 | adap->timeout = 100; /* default values, should */ | |
480 | adap->retries = 3; /* be replaced by defines */ | |
481 | ||
b39ad0cf MH |
482 | if ((rval = pcf_init_8584(pcf_adap))) |
483 | return rval; | |
484 | ||
485 | rval = i2c_add_adapter(adap); | |
486 | ||
1da177e4 LT |
487 | return rval; |
488 | } | |
1da177e4 | 489 | EXPORT_SYMBOL(i2c_pcf_add_bus); |
1da177e4 LT |
490 | |
491 | MODULE_AUTHOR("Hans Berglund <hb@spacetec.no>"); | |
492 | MODULE_DESCRIPTION("I2C-Bus PCF8584 algorithm"); | |
493 | MODULE_LICENSE("GPL"); | |
494 | ||
495 | module_param(i2c_debug, int, S_IRUGO | S_IWUSR); | |
496 | MODULE_PARM_DESC(i2c_debug, | |
497 | "debug level - 0 off; 1 normal; 2,3 more verbose; 9 pcf-protocol"); |