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
22 /* With some changes from Ky�sti M�lkki <kmalkki@cc.hut.fi> and
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/sched.h>
37 #include <linux/i2c.h>
38 #include <linux/i2c-algo-pcf.h>
39 #include "i2c-pcf8584.h"
40
41
42 /* ----- global defines ----------------------------------------------- */
43 #define DEB(x) if (i2c_debug>=1) x
44 #define DEB2(x) if (i2c_debug>=2) x
45 #define DEB3(x) if (i2c_debug>=3) x /* print several statistical values*/
46 #define DEBPROTO(x) if (i2c_debug>=9) x;
47 /* debug the protocol by showing transferred bits */
48 #define DEF_TIMEOUT 16
49
50 /* module parameters:
51 */
52 static int i2c_debug=0;
53 static int pcf_scan=0; /* have a look at what's hanging 'round */
54
55 /* --- setting states on the bus with the right timing: --------------- */
56
57 #define set_pcf(adap, ctl, val) adap->setpcf(adap->data, ctl, val)
58 #define get_pcf(adap, ctl) adap->getpcf(adap->data, ctl)
59 #define get_own(adap) adap->getown(adap->data)
60 #define get_clock(adap) adap->getclock(adap->data)
61 #define i2c_outb(adap, val) adap->setpcf(adap->data, 0, val)
62 #define i2c_inb(adap) adap->getpcf(adap->data, 0)
63
64 /* --- other auxiliary functions -------------------------------------- */
65
i2c_start(struct i2c_algo_pcf_data * adap)66 static void i2c_start(struct i2c_algo_pcf_data *adap)
67 {
68 DEBPROTO(printk("S "));
69 set_pcf(adap, 1, I2C_PCF_START);
70 }
71
i2c_repstart(struct i2c_algo_pcf_data * adap)72 static void i2c_repstart(struct i2c_algo_pcf_data *adap)
73 {
74 DEBPROTO(printk(" Sr "));
75 set_pcf(adap, 1, I2C_PCF_REPSTART);
76 }
77
78
i2c_stop(struct i2c_algo_pcf_data * adap)79 static void i2c_stop(struct i2c_algo_pcf_data *adap)
80 {
81 DEBPROTO(printk("P\n"));
82 set_pcf(adap, 1, I2C_PCF_STOP);
83 }
84
85
wait_for_bb(struct i2c_algo_pcf_data * adap)86 static int wait_for_bb(struct i2c_algo_pcf_data *adap) {
87
88 int timeout = DEF_TIMEOUT;
89 int status;
90
91 status = get_pcf(adap, 1);
92 #ifndef STUB_I2C
93 while (timeout-- && !(status & I2C_PCF_BB)) {
94 udelay(100); /* wait for 100 us */
95 status = get_pcf(adap, 1);
96 }
97 #endif
98 if (timeout <= 0) {
99 printk(KERN_ERR "Timeout waiting for Bus Busy\n");
100 }
101
102 return (timeout<=0);
103 }
104
105
pcf_sleep(unsigned long timeout)106 static inline void pcf_sleep(unsigned long timeout)
107 {
108 schedule_timeout( timeout * HZ);
109 }
110
111
wait_for_pin(struct i2c_algo_pcf_data * adap,int * status)112 static int wait_for_pin(struct i2c_algo_pcf_data *adap, int *status) {
113
114 int timeout = DEF_TIMEOUT;
115
116 *status = get_pcf(adap, 1);
117 #ifndef STUB_I2C
118 while (timeout-- && (*status & I2C_PCF_PIN)) {
119 adap->waitforpin();
120 *status = get_pcf(adap, 1);
121 }
122 #endif
123 if (timeout <= 0)
124 return(-1);
125 else
126 return(0);
127 }
128
129 /*
130 * This should perform the 'PCF8584 initialization sequence' as described
131 * in the Philips IC12 data book (1995, Aug 29).
132 * There should be a 30 clock cycle wait after reset, I assume this
133 * has been fulfilled.
134 * There should be a delay at the end equal to the longest I2C message
135 * to synchronize the BB-bit (in multimaster systems). How long is
136 * this? I assume 1 second is always long enough.
137 *
138 * vdovikin: added detect code for PCF8584
139 */
pcf_init_8584(struct i2c_algo_pcf_data * adap)140 static int pcf_init_8584 (struct i2c_algo_pcf_data *adap)
141 {
142 unsigned char temp;
143
144 DEB3(printk(KERN_DEBUG "i2c-algo-pcf.o: PCF state 0x%02x\n", get_pcf(adap, 1)));
145
146 /* S1=0x80: S0 selected, serial interface off */
147 set_pcf(adap, 1, I2C_PCF_PIN);
148 /* check to see S1 now used as R/W ctrl -
149 PCF8584 does that when ESO is zero */
150 /* PCF also resets PIN bit */
151 if ((temp = get_pcf(adap, 1)) != (0)) {
152 DEB2(printk(KERN_ERR "i2c-algo-pcf.o: PCF detection failed -- can't select S0 (0x%02x).\n", temp));
153 return -ENXIO; /* definetly not PCF8584 */
154 }
155
156 /* load own address in S0, effective address is (own << 1) */
157 i2c_outb(adap, get_own(adap));
158 /* check it's realy writen */
159 if ((temp = i2c_inb(adap)) != get_own(adap)) {
160 DEB2(printk(KERN_ERR "i2c-algo-pcf.o: PCF detection failed -- can't set S0 (0x%02x).\n", temp));
161 return -ENXIO;
162 }
163
164 /* S1=0xA0, next byte in S2 */
165 set_pcf(adap, 1, I2C_PCF_PIN | I2C_PCF_ES1);
166 /* check to see S2 now selected */
167 if ((temp = get_pcf(adap, 1)) != I2C_PCF_ES1) {
168 DEB2(printk(KERN_ERR "i2c-algo-pcf.o: PCF detection failed -- can't select S2 (0x%02x).\n", temp));
169 return -ENXIO;
170 }
171
172 /* load clock register S2 */
173 i2c_outb(adap, get_clock(adap));
174 /* check it's realy writen, the only 5 lowest bits does matter */
175 if (((temp = i2c_inb(adap)) & 0x1f) != get_clock(adap)) {
176 DEB2(printk(KERN_ERR "i2c-algo-pcf.o: PCF detection failed -- can't set S2 (0x%02x).\n", temp));
177 return -ENXIO;
178 }
179
180 /* Enable serial interface, idle, S0 selected */
181 set_pcf(adap, 1, I2C_PCF_IDLE);
182
183 /* check to see PCF is realy idled and we can access status register */
184 if ((temp = get_pcf(adap, 1)) != (I2C_PCF_PIN | I2C_PCF_BB)) {
185 DEB2(printk(KERN_ERR "i2c-algo-pcf.o: PCF detection failed -- can't select S1` (0x%02x).\n", temp));
186 return -ENXIO;
187 }
188
189 printk(KERN_DEBUG "i2c-algo-pcf.o: deteted and initialized PCF8584.\n");
190
191 return 0;
192 }
193
194
195 /* ----- Utility functions
196 */
197
try_address(struct i2c_algo_pcf_data * adap,unsigned char addr,int retries)198 static inline int try_address(struct i2c_algo_pcf_data *adap,
199 unsigned char addr, int retries)
200 {
201 int i, status, ret = -1;
202 for (i=0;i<retries;i++) {
203 i2c_outb(adap, addr);
204 i2c_start(adap);
205 status = get_pcf(adap, 1);
206 if (wait_for_pin(adap, &status) >= 0) {
207 if ((status & I2C_PCF_LRB) == 0) {
208 i2c_stop(adap);
209 break; /* success! */
210 }
211 }
212 i2c_stop(adap);
213 udelay(adap->udelay);
214 }
215 DEB2(if (i) printk(KERN_DEBUG "i2c-algo-pcf.o: needed %d retries for %d\n",i,
216 addr));
217 return ret;
218 }
219
220
pcf_sendbytes(struct i2c_adapter * i2c_adap,const char * buf,int count,int last)221 static int pcf_sendbytes(struct i2c_adapter *i2c_adap, const char *buf,
222 int count, int last)
223 {
224 struct i2c_algo_pcf_data *adap = i2c_adap->algo_data;
225 int wrcount, status, timeout;
226
227 for (wrcount=0; wrcount<count; ++wrcount) {
228 DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: %s i2c_write: writing %2.2X\n",
229 i2c_adap->name, buf[wrcount]&0xff));
230 i2c_outb(adap, buf[wrcount]);
231 timeout = wait_for_pin(adap, &status);
232 if (timeout) {
233 i2c_stop(adap);
234 printk(KERN_ERR "i2c-algo-pcf.o: %s i2c_write: "
235 "error - timeout.\n", i2c_adap->name);
236 return -EREMOTEIO; /* got a better one ?? */
237 }
238 #ifndef STUB_I2C
239 if (status & I2C_PCF_LRB) {
240 i2c_stop(adap);
241 printk(KERN_ERR "i2c-algo-pcf.o: %s i2c_write: "
242 "error - no ack.\n", i2c_adap->name);
243 return -EREMOTEIO; /* got a better one ?? */
244 }
245 #endif
246 }
247 if (last) {
248 i2c_stop(adap);
249 }
250 else {
251 i2c_repstart(adap);
252 }
253
254 return (wrcount);
255 }
256
257
pcf_readbytes(struct i2c_adapter * i2c_adap,char * buf,int count,int last)258 static int pcf_readbytes(struct i2c_adapter *i2c_adap, char *buf,
259 int count, int last)
260 {
261 int i, status;
262 struct i2c_algo_pcf_data *adap = i2c_adap->algo_data;
263
264 /* increment number of bytes to read by one -- read dummy byte */
265 for (i = 0; i <= count; i++) {
266
267 if (wait_for_pin(adap, &status)) {
268 i2c_stop(adap);
269 printk(KERN_ERR "i2c-algo-pcf.o: pcf_readbytes timed out.\n");
270 return (-1);
271 }
272
273 #ifndef STUB_I2C
274 if ((status & I2C_PCF_LRB) && (i != count)) {
275 i2c_stop(adap);
276 printk(KERN_ERR "i2c-algo-pcf.o: i2c_read: i2c_inb, No ack.\n");
277 return (-1);
278 }
279 #endif
280
281 if (i == count - 1) {
282 set_pcf(adap, 1, I2C_PCF_ESO);
283 } else
284 if (i == count) {
285 if (last) {
286 i2c_stop(adap);
287 } else {
288 i2c_repstart(adap);
289 }
290 };
291
292 if (i) {
293 buf[i - 1] = i2c_inb(adap);
294 } else {
295 i2c_inb(adap); /* dummy read */
296 }
297 }
298
299 return (i - 1);
300 }
301
302
pcf_doAddress(struct i2c_algo_pcf_data * adap,struct i2c_msg * msg,int retries)303 static inline int pcf_doAddress(struct i2c_algo_pcf_data *adap,
304 struct i2c_msg *msg, int retries)
305 {
306 unsigned short flags = msg->flags;
307 unsigned char addr;
308 int ret;
309 if ( (flags & I2C_M_TEN) ) {
310 /* a ten bit address */
311 addr = 0xf0 | (( msg->addr >> 7) & 0x03);
312 DEB2(printk(KERN_DEBUG "addr0: %d\n",addr));
313 /* try extended address code...*/
314 ret = try_address(adap, addr, retries);
315 if (ret!=1) {
316 printk(KERN_ERR "died at extended address code.\n");
317 return -EREMOTEIO;
318 }
319 /* the remaining 8 bit address */
320 i2c_outb(adap,msg->addr & 0x7f);
321 /* Status check comes here */
322 if (ret != 1) {
323 printk(KERN_ERR "died at 2nd address code.\n");
324 return -EREMOTEIO;
325 }
326 if ( flags & I2C_M_RD ) {
327 i2c_repstart(adap);
328 /* okay, now switch into reading mode */
329 addr |= 0x01;
330 ret = try_address(adap, addr, retries);
331 if (ret!=1) {
332 printk(KERN_ERR "died at extended address code.\n");
333 return -EREMOTEIO;
334 }
335 }
336 } else { /* normal 7bit address */
337 addr = ( msg->addr << 1 );
338 if (flags & I2C_M_RD )
339 addr |= 1;
340 if (flags & I2C_M_REV_DIR_ADDR )
341 addr ^= 1;
342 i2c_outb(adap, addr);
343 }
344 return 0;
345 }
346
pcf_xfer(struct i2c_adapter * i2c_adap,struct i2c_msg msgs[],int num)347 static int pcf_xfer(struct i2c_adapter *i2c_adap,
348 struct i2c_msg msgs[],
349 int num)
350 {
351 struct i2c_algo_pcf_data *adap = i2c_adap->algo_data;
352 struct i2c_msg *pmsg;
353 int i;
354 int ret=0, timeout, status;
355
356
357 /* Check for bus busy */
358 timeout = wait_for_bb(adap);
359 if (timeout) {
360 DEB2(printk(KERN_ERR "i2c-algo-pcf.o: "
361 "Timeout waiting for BB in pcf_xfer\n");)
362 return -EIO;
363 }
364
365 for (i = 0;ret >= 0 && i < num; i++) {
366 pmsg = &msgs[i];
367
368 DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: Doing %s %d bytes to 0x%02x - %d of %d messages\n",
369 pmsg->flags & I2C_M_RD ? "read" : "write",
370 pmsg->len, pmsg->addr, i + 1, num);)
371
372 ret = pcf_doAddress(adap, pmsg, i2c_adap->retries);
373
374 /* Send START */
375 if (i == 0) {
376 i2c_start(adap);
377 }
378
379 /* Wait for PIN (pending interrupt NOT) */
380 timeout = wait_for_pin(adap, &status);
381 if (timeout) {
382 i2c_stop(adap);
383 DEB2(printk(KERN_ERR "i2c-algo-pcf.o: Timeout waiting "
384 "for PIN(1) in pcf_xfer\n");)
385 return (-EREMOTEIO);
386 }
387
388 #ifndef STUB_I2C
389 /* Check LRB (last rcvd bit - slave ack) */
390 if (status & I2C_PCF_LRB) {
391 i2c_stop(adap);
392 DEB2(printk(KERN_ERR "i2c-algo-pcf.o: No LRB(1) in pcf_xfer\n");)
393 return (-EREMOTEIO);
394 }
395 #endif
396
397 DEB3(printk(KERN_DEBUG "i2c-algo-pcf.o: Msg %d, addr=0x%x, flags=0x%x, len=%d\n",
398 i, msgs[i].addr, msgs[i].flags, msgs[i].len);)
399
400 /* Read */
401 if (pmsg->flags & I2C_M_RD) {
402 /* read bytes into buffer*/
403 ret = pcf_readbytes(i2c_adap, pmsg->buf, pmsg->len,
404 (i + 1 == num));
405
406 if (ret != pmsg->len) {
407 DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: fail: "
408 "only read %d bytes.\n",ret));
409 } else {
410 DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: read %d bytes.\n",ret));
411 }
412 } else { /* Write */
413 ret = pcf_sendbytes(i2c_adap, pmsg->buf, pmsg->len,
414 (i + 1 == num));
415
416 if (ret != pmsg->len) {
417 DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: fail: "
418 "only wrote %d bytes.\n",ret));
419 } else {
420 DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: wrote %d bytes.\n",ret));
421 }
422 }
423 }
424
425 return (i);
426 }
427
algo_control(struct i2c_adapter * adapter,unsigned int cmd,unsigned long arg)428 static int algo_control(struct i2c_adapter *adapter,
429 unsigned int cmd, unsigned long arg)
430 {
431 return 0;
432 }
433
pcf_func(struct i2c_adapter * adap)434 static u32 pcf_func(struct i2c_adapter *adap)
435 {
436 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
437 I2C_FUNC_10BIT_ADDR | I2C_FUNC_PROTOCOL_MANGLING;
438 }
439
440 /* -----exported algorithm data: ------------------------------------- */
441
442 static struct i2c_algorithm pcf_algo = {
443 .name = "PCF8584 algorithm",
444 .id = I2C_ALGO_PCF,
445 .master_xfer = pcf_xfer,
446 .algo_control = algo_control,
447 .functionality = pcf_func,
448 };
449
450 /*
451 * registering functions to load algorithms at runtime
452 */
i2c_pcf_add_bus(struct i2c_adapter * adap)453 int i2c_pcf_add_bus(struct i2c_adapter *adap)
454 {
455 int i, status;
456 struct i2c_algo_pcf_data *pcf_adap = adap->algo_data;
457
458 DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: hw routines for %s registered.\n",
459 adap->name));
460
461 /* register new adapter to i2c module... */
462
463 adap->id |= pcf_algo.id;
464 adap->algo = &pcf_algo;
465
466 adap->timeout = 100; /* default values, should */
467 adap->retries = 3; /* be replaced by defines */
468
469 if ((i = pcf_init_8584(pcf_adap))) {
470 return i;
471 }
472
473 #ifdef MODULE
474 MOD_INC_USE_COUNT;
475 #endif
476
477 /* scan bus */
478 if (pcf_scan) {
479 printk(KERN_INFO " i2c-algo-pcf.o: scanning bus %s.\n",
480 adap->name);
481 for (i = 0x00; i < 0xff; i+=2) {
482 if (wait_for_bb(pcf_adap)) {
483 printk(KERN_INFO " i2c-algo-pcf.o: scanning bus %s - TIMEOUTed.\n",
484 adap->name);
485 break;
486 }
487 i2c_outb(pcf_adap, i);
488 i2c_start(pcf_adap);
489 if ((wait_for_pin(pcf_adap, &status) >= 0) &&
490 ((status & I2C_PCF_LRB) == 0)) {
491 printk("(%02x)",i>>1);
492 } else {
493 printk(".");
494 }
495 i2c_stop(pcf_adap);
496 udelay(pcf_adap->udelay);
497 }
498 printk("\n");
499 }
500
501 return i2c_add_adapter(adap);
502 }
503
504
i2c_pcf_del_bus(struct i2c_adapter * adap)505 int i2c_pcf_del_bus(struct i2c_adapter *adap)
506 {
507 int res;
508 if ((res = i2c_del_adapter(adap)) < 0)
509 return res;
510 DEB2(printk("i2c-algo-pcf.o: adapter unregistered: %s\n",adap->name));
511
512 #ifdef MODULE
513 MOD_DEC_USE_COUNT;
514 #endif
515 return 0;
516 }
517
i2c_algo_pcf_init(void)518 int __init i2c_algo_pcf_init (void)
519 {
520 printk("i2c-algo-pcf.o: i2c pcf8584 algorithm module\n");
521 return 0;
522 }
523
524 EXPORT_SYMBOL(i2c_pcf_add_bus);
525 EXPORT_SYMBOL(i2c_pcf_del_bus);
526
527 #ifdef MODULE
528 MODULE_AUTHOR("Hans Berglund <hb@spacetec.no>");
529 MODULE_DESCRIPTION("I2C-Bus PCF8584 algorithm");
530 MODULE_LICENSE("GPL");
531
532 MODULE_PARM(pcf_scan, "i");
533 MODULE_PARM(i2c_debug,"i");
534
535 MODULE_PARM_DESC(pcf_scan, "Scan for active chips on the bus");
536 MODULE_PARM_DESC(i2c_debug,
537 "debug level - 0 off; 1 normal; 2,3 more verbose; 9 pcf-protocol");
538
539
init_module(void)540 int init_module(void)
541 {
542 return i2c_algo_pcf_init();
543 }
544
cleanup_module(void)545 void cleanup_module(void)
546 {
547 }
548 #endif
549