Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6
[linux-2.6] / drivers / i2c / algos / i2c-algo-pcf.c
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 Kyösti Mälkki <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/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
461 static const struct i2c_algorithm pcf_algo = {
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... */
477         adap->algo = &pcf_algo;
478
479         adap->timeout = 100;            /* default values, should       */
480         adap->retries = 3;              /* be replaced by defines       */
481
482         if ((rval = pcf_init_8584(pcf_adap)))
483                 return rval;
484
485         rval = i2c_add_adapter(adap);
486
487         return rval;
488 }
489
490
491 int i2c_pcf_del_bus(struct i2c_adapter *adap)
492 {
493         return i2c_del_adapter(adap);
494 }
495
496 EXPORT_SYMBOL(i2c_pcf_add_bus);
497 EXPORT_SYMBOL(i2c_pcf_del_bus);
498
499 MODULE_AUTHOR("Hans Berglund <hb@spacetec.no>");
500 MODULE_DESCRIPTION("I2C-Bus PCF8584 algorithm");
501 MODULE_LICENSE("GPL");
502
503 module_param(i2c_debug, int, S_IRUGO | S_IWUSR);
504 MODULE_PARM_DESC(i2c_debug,
505         "debug level - 0 off; 1 normal; 2,3 more verbose; 9 pcf-protocol");