[PATCH] I2C: Kill i2c_algorithm.name (1/7)
[linux-2.6.git] / drivers / i2c / algos / i2c-algo-bit.c
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
21 /* With some changes from Frodo Looijaard <frodol@dds.nl>, Kyösti Mälkki
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 ----------------------------------------------- */
36 #define DEB(x) if (i2c_debug>=1) x;
37 #define DEB2(x) if (i2c_debug>=2) x;
38 #define DEBSTAT(x) if (i2c_debug>=3) x; /* print several statistical values*/
39 #define DEBPROTO(x) if (i2c_debug>=9) { x; }
40         /* debug the protocol by showing transferred bits */
41
42
43 /* ----- global variables --------------------------------------------- */
44
45 /* module parameters:
46  */
47 static int i2c_debug;
48 static int bit_test;    /* see if the line-setting functions work       */
49
50 /* --- setting states on the bus with the right timing: --------------- */
51
52 #define setsda(adap,val) adap->setsda(adap->data, val)
53 #define setscl(adap,val) adap->setscl(adap->data, val)
54 #define getsda(adap) adap->getsda(adap->data)
55 #define getscl(adap) adap->getscl(adap->data)
56
57 static inline void sdalo(struct i2c_algo_bit_data *adap)
58 {
59         setsda(adap,0);
60         udelay(adap->udelay);
61 }
62
63 static inline void sdahi(struct i2c_algo_bit_data *adap)
64 {
65         setsda(adap,1);
66         udelay(adap->udelay);
67 }
68
69 static inline void scllo(struct i2c_algo_bit_data *adap)
70 {
71         setscl(adap,0);
72         udelay(adap->udelay);
73 }
74
75 /*
76  * Raise scl line, and do checking for delays. This is necessary for slower
77  * devices.
78  */
79 static inline int sclhi(struct i2c_algo_bit_data *adap)
80 {
81         unsigned long start;
82
83         setscl(adap,1);
84
85         /* Not all adapters have scl sense line... */
86         if (adap->getscl == NULL ) {
87                 udelay(adap->udelay);
88                 return 0;
89         }
90
91         start=jiffies;
92         while (! getscl(adap) ) {       
93                 /* the hw knows how to read the clock line,
94                  * so we wait until it actually gets high.
95                  * This is safer as some chips may hold it low
96                  * while they are processing data internally. 
97                  */
98                 if (time_after_eq(jiffies, start+adap->timeout)) {
99                         return -ETIMEDOUT;
100                 }
101                 cond_resched();
102         }
103         DEBSTAT(printk(KERN_DEBUG "needed %ld jiffies\n", jiffies-start));
104         udelay(adap->udelay);
105         return 0;
106
107
108
109 /* --- other auxiliary functions -------------------------------------- */
110 static void i2c_start(struct i2c_algo_bit_data *adap) 
111 {
112         /* assert: scl, sda are high */
113         DEBPROTO(printk("S "));
114         sdalo(adap);
115         scllo(adap);
116 }
117
118 static void i2c_repstart(struct i2c_algo_bit_data *adap) 
119 {
120         /* scl, sda may not be high */
121         DEBPROTO(printk(" Sr "));
122         setsda(adap,1);
123         sclhi(adap);
124         udelay(adap->udelay);
125         
126         sdalo(adap);
127         scllo(adap);
128 }
129
130
131 static void i2c_stop(struct i2c_algo_bit_data *adap) 
132 {
133         DEBPROTO(printk("P\n"));
134         /* assert: scl is low */
135         sdalo(adap);
136         sclhi(adap); 
137         sdahi(adap);
138 }
139
140
141
142 /* send a byte without start cond., look for arbitration, 
143    check ackn. from slave */
144 /* returns:
145  * 1 if the device acknowledged
146  * 0 if the device did not ack
147  * -ETIMEDOUT if an error occurred (while raising the scl line)
148  */
149 static int i2c_outb(struct i2c_adapter *i2c_adap, char c)
150 {
151         int i;
152         int sb;
153         int ack;
154         struct i2c_algo_bit_data *adap = i2c_adap->algo_data;
155
156         /* assert: scl is low */
157         for ( i=7 ; i>=0 ; i-- ) {
158                 sb = c & ( 1 << i );
159                 setsda(adap,sb);
160                 udelay(adap->udelay);
161                 DEBPROTO(printk(KERN_DEBUG "%d",sb!=0));
162                 if (sclhi(adap)<0) { /* timed out */
163                         sdahi(adap); /* we don't want to block the net */
164                         DEB2(printk(KERN_DEBUG " i2c_outb: 0x%02x, timeout at bit #%d\n", c&0xff, i));
165                         return -ETIMEDOUT;
166                 };
167                 /* do arbitration here: 
168                  * if ( sb && ! getsda(adap) ) -> ouch! Get out of here.
169                  */
170                 setscl(adap, 0 );
171                 udelay(adap->udelay);
172         }
173         sdahi(adap);
174         if (sclhi(adap)<0){ /* timeout */
175             DEB2(printk(KERN_DEBUG " i2c_outb: 0x%02x, timeout at ack\n", c&0xff));
176             return -ETIMEDOUT;
177         };
178         /* read ack: SDA should be pulled down by slave */
179         ack=getsda(adap);       /* ack: sda is pulled low ->success.     */
180         DEB2(printk(KERN_DEBUG " i2c_outb: 0x%02x , getsda() = %d\n", c & 0xff, ack));
181
182         DEBPROTO( printk(KERN_DEBUG "[%2.2x]",c&0xff) );
183         DEBPROTO(if (0==ack){ printk(KERN_DEBUG " A ");} else printk(KERN_DEBUG " NA ") );
184         scllo(adap);
185         return 0==ack;          /* return 1 if device acked      */
186         /* assert: scl is low (sda undef) */
187 }
188
189
190 static int i2c_inb(struct i2c_adapter *i2c_adap) 
191 {
192         /* read byte via i2c port, without start/stop sequence  */
193         /* acknowledge is sent in i2c_read.                     */
194         int i;
195         unsigned char indata=0;
196         struct i2c_algo_bit_data *adap = i2c_adap->algo_data;
197
198         /* assert: scl is low */
199         sdahi(adap);
200         for (i=0;i<8;i++) {
201                 if (sclhi(adap)<0) { /* timeout */
202                         DEB2(printk(KERN_DEBUG " i2c_inb: timeout at bit #%d\n", 7-i));
203                         return -ETIMEDOUT;
204                 };
205                 indata *= 2;
206                 if ( getsda(adap) ) 
207                         indata |= 0x01;
208                 scllo(adap);
209         }
210         /* assert: scl is low */
211         DEB2(printk(KERN_DEBUG "i2c_inb: 0x%02x\n", indata & 0xff));
212
213         DEBPROTO(printk(KERN_DEBUG " 0x%02x", indata & 0xff));
214         return (int) (indata & 0xff);
215 }
216
217 /*
218  * Sanity check for the adapter hardware - check the reaction of
219  * the bus lines only if it seems to be idle.
220  */
221 static int test_bus(struct i2c_algo_bit_data *adap, char* name) {
222         int scl,sda;
223
224         if (adap->getscl==NULL)
225                 printk(KERN_INFO "i2c-algo-bit.o: Testing SDA only, "
226                         "SCL is not readable.\n");
227
228         sda=getsda(adap);
229         scl=(adap->getscl==NULL?1:getscl(adap));
230         printk(KERN_DEBUG "i2c-algo-bit.o: (0) scl=%d, sda=%d\n",scl,sda);
231         if (!scl || !sda ) {
232                 printk(KERN_WARNING "i2c-algo-bit.o: %s seems to be busy.\n", name);
233                 goto bailout;
234         }
235
236         sdalo(adap);
237         sda=getsda(adap);
238         scl=(adap->getscl==NULL?1:getscl(adap));
239         printk(KERN_DEBUG "i2c-algo-bit.o: (1) scl=%d, sda=%d\n",scl,sda);
240         if ( 0 != sda ) {
241                 printk(KERN_WARNING "i2c-algo-bit.o: SDA stuck high!\n");
242                 goto bailout;
243         }
244         if ( 0 == scl ) {
245                 printk(KERN_WARNING "i2c-algo-bit.o: SCL unexpected low "
246                         "while pulling SDA low!\n");
247                 goto bailout;
248         }               
249
250         sdahi(adap);
251         sda=getsda(adap);
252         scl=(adap->getscl==NULL?1:getscl(adap));
253         printk(KERN_DEBUG "i2c-algo-bit.o: (2) scl=%d, sda=%d\n",scl,sda);
254         if ( 0 == sda ) {
255                 printk(KERN_WARNING "i2c-algo-bit.o: SDA stuck low!\n");
256                 goto bailout;
257         }
258         if ( 0 == scl ) {
259                 printk(KERN_WARNING "i2c-algo-bit.o: SCL unexpected low "
260                         "while pulling SDA high!\n");
261                 goto bailout;
262         }
263
264         scllo(adap);
265         sda=getsda(adap);
266         scl=(adap->getscl==NULL?0:getscl(adap));
267         printk(KERN_DEBUG "i2c-algo-bit.o: (3) scl=%d, sda=%d\n",scl,sda);
268         if ( 0 != scl ) {
269                 printk(KERN_WARNING "i2c-algo-bit.o: SCL stuck high!\n");
270                 goto bailout;
271         }
272         if ( 0 == sda ) {
273                 printk(KERN_WARNING "i2c-algo-bit.o: SDA unexpected low "
274                         "while pulling SCL low!\n");
275                 goto bailout;
276         }
277         
278         sclhi(adap);
279         sda=getsda(adap);
280         scl=(adap->getscl==NULL?1:getscl(adap));
281         printk(KERN_DEBUG "i2c-algo-bit.o: (4) scl=%d, sda=%d\n",scl,sda);
282         if ( 0 == scl ) {
283                 printk(KERN_WARNING "i2c-algo-bit.o: SCL stuck low!\n");
284                 goto bailout;
285         }
286         if ( 0 == sda ) {
287                 printk(KERN_WARNING "i2c-algo-bit.o: SDA unexpected low "
288                         "while pulling SCL high!\n");
289                 goto bailout;
290         }
291         printk(KERN_INFO "i2c-algo-bit.o: %s passed test.\n",name);
292         return 0;
293 bailout:
294         sdahi(adap);
295         sclhi(adap);
296         return -ENODEV;
297 }
298
299 /* ----- Utility functions
300  */
301
302 /* try_address tries to contact a chip for a number of
303  * times before it gives up.
304  * return values:
305  * 1 chip answered
306  * 0 chip did not answer
307  * -x transmission error
308  */
309 static inline int try_address(struct i2c_adapter *i2c_adap,
310                        unsigned char addr, int retries)
311 {
312         struct i2c_algo_bit_data *adap = i2c_adap->algo_data;
313         int i,ret = -1;
314         for (i=0;i<=retries;i++) {
315                 ret = i2c_outb(i2c_adap,addr);
316                 if (ret==1)
317                         break;  /* success! */
318                 i2c_stop(adap);
319                 udelay(5/*adap->udelay*/);
320                 if (i==retries)  /* no success */
321                         break;
322                 i2c_start(adap);
323                 udelay(adap->udelay);
324         }
325         DEB2(if (i)
326              printk(KERN_DEBUG "i2c-algo-bit.o: Used %d tries to %s client at 0x%02x : %s\n",
327                     i+1, addr & 1 ? "read" : "write", addr>>1,
328                     ret==1 ? "success" : ret==0 ? "no ack" : "failed, timeout?" )
329             );
330         return ret;
331 }
332
333 static int sendbytes(struct i2c_adapter *i2c_adap, struct i2c_msg *msg)
334 {
335         struct i2c_algo_bit_data *adap = i2c_adap->algo_data;
336         char c;
337         const char *temp = msg->buf;
338         int count = msg->len;
339         unsigned short nak_ok = msg->flags & I2C_M_IGNORE_NAK; 
340         int retval;
341         int wrcount=0;
342
343         while (count > 0) {
344                 c = *temp;
345                 DEB2(dev_dbg(&i2c_adap->dev, "sendbytes: writing %2.2X\n", c&0xff));
346                 retval = i2c_outb(i2c_adap,c);
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");
353                         i2c_stop(adap);
354                         return (retval<0)? retval : -EFAULT;
355                                 /* got a better one ?? */
356                 }
357 #if 0
358                 /* from asm/delay.h */
359                 __delay(adap->mdelay * (loops_per_sec / 1000) );
360 #endif
361         }
362         return wrcount;
363 }
364
365 static inline int readbytes(struct i2c_adapter *i2c_adap, struct i2c_msg *msg)
366 {
367         int inval;
368         int rdcount=0;          /* counts bytes read */
369         struct i2c_algo_bit_data *adap = i2c_adap->algo_data;
370         char *temp = msg->buf;
371         int count = msg->len;
372
373         while (count > 0) {
374                 inval = i2c_inb(i2c_adap);
375 /*printk("%#02x ",inval); if ( ! (count % 16) ) printk("\n"); */
376                 if (inval>=0) {
377                         *temp = inval;
378                         rdcount++;
379                 } else {   /* read timed out */
380                         printk(KERN_ERR "i2c-algo-bit.o: readbytes: i2c_inb timed out.\n");
381                         break;
382                 }
383
384                 temp++;
385                 count--;
386
387                 if (msg->flags & I2C_M_NO_RD_ACK)
388                         continue;
389
390                 if ( count > 0 ) {              /* send ack */
391                         sdalo(adap);
392                         DEBPROTO(printk(" Am "));
393                 } else {
394                         sdahi(adap);    /* neg. ack on last byte */
395                         DEBPROTO(printk(" NAm "));
396                 }
397                 if (sclhi(adap)<0) {    /* timeout */
398                         sdahi(adap);
399                         printk(KERN_ERR "i2c-algo-bit.o: readbytes: Timeout at ack\n");
400                         return -ETIMEDOUT;
401                 };
402                 scllo(adap);
403                 sdahi(adap);
404         }
405         return rdcount;
406 }
407
408 /* doAddress initiates the transfer by generating the start condition (in
409  * try_address) and transmits the address in the necessary format to handle
410  * reads, writes as well as 10bit-addresses.
411  * returns:
412  *  0 everything went okay, the chip ack'ed, or IGNORE_NAK flag was set
413  * -x an error occurred (like: -EREMOTEIO if the device did not answer, or
414  *      -ETIMEDOUT, for example if the lines are stuck...) 
415  */
416 static inline int bit_doAddress(struct i2c_adapter *i2c_adap, struct i2c_msg *msg) 
417 {
418         unsigned short flags = msg->flags;
419         unsigned short nak_ok = msg->flags & I2C_M_IGNORE_NAK;
420         struct i2c_algo_bit_data *adap = i2c_adap->algo_data;
421
422         unsigned char addr;
423         int ret, retries;
424
425         retries = nak_ok ? 0 : i2c_adap->retries;
426         
427         if ( (flags & I2C_M_TEN)  ) { 
428                 /* a ten bit address */
429                 addr = 0xf0 | (( msg->addr >> 7) & 0x03);
430                 DEB2(printk(KERN_DEBUG "addr0: %d\n",addr));
431                 /* try extended address code...*/
432                 ret = try_address(i2c_adap, addr, retries);
433                 if ((ret != 1) && !nak_ok)  {
434                         printk(KERN_ERR "died at extended address code.\n");
435                         return -EREMOTEIO;
436                 }
437                 /* the remaining 8 bit address */
438                 ret = i2c_outb(i2c_adap,msg->addr & 0x7f);
439                 if ((ret != 1) && !nak_ok) {
440                         /* the chip did not ack / xmission error occurred */
441                         printk(KERN_ERR "died at 2nd address code.\n");
442                         return -EREMOTEIO;
443                 }
444                 if ( flags & I2C_M_RD ) {
445                         i2c_repstart(adap);
446                         /* okay, now switch into reading mode */
447                         addr |= 0x01;
448                         ret = try_address(i2c_adap, addr, retries);
449                         if ((ret!=1) && !nak_ok) {
450                                 printk(KERN_ERR "died at extended address code.\n");
451                                 return -EREMOTEIO;
452                         }
453                 }
454         } else {                /* normal 7bit address  */
455                 addr = ( msg->addr << 1 );
456                 if (flags & I2C_M_RD )
457                         addr |= 1;
458                 if (flags & I2C_M_REV_DIR_ADDR )
459                         addr ^= 1;
460                 ret = try_address(i2c_adap, addr, retries);
461                 if ((ret!=1) && !nak_ok)
462                         return -EREMOTEIO;
463         }
464
465         return 0;
466 }
467
468 static int bit_xfer(struct i2c_adapter *i2c_adap,
469                     struct i2c_msg msgs[], int num)
470 {
471         struct i2c_msg *pmsg;
472         struct i2c_algo_bit_data *adap = i2c_adap->algo_data;
473         
474         int i,ret;
475         unsigned short nak_ok;
476
477         i2c_start(adap);
478         for (i=0;i<num;i++) {
479                 pmsg = &msgs[i];
480                 nak_ok = pmsg->flags & I2C_M_IGNORE_NAK; 
481                 if (!(pmsg->flags & I2C_M_NOSTART)) {
482                         if (i) {
483                                 i2c_repstart(adap);
484                         }
485                         ret = bit_doAddress(i2c_adap, pmsg);
486                         if ((ret != 0) && !nak_ok) {
487                             DEB2(printk(KERN_DEBUG "i2c-algo-bit.o: NAK from device addr %2.2x msg #%d\n"
488                                         ,msgs[i].addr,i));
489                             return (ret<0) ? ret : -EREMOTEIO;
490                         }
491                 }
492                 if (pmsg->flags & I2C_M_RD ) {
493                         /* read bytes into buffer*/
494                         ret = readbytes(i2c_adap, pmsg);
495                         DEB2(printk(KERN_DEBUG "i2c-algo-bit.o: read %d bytes.\n",ret));
496                         if (ret < pmsg->len ) {
497                                 return (ret<0)? ret : -EREMOTEIO;
498                         }
499                 } else {
500                         /* write bytes from buffer */
501                         ret = sendbytes(i2c_adap, pmsg);
502                         DEB2(printk(KERN_DEBUG "i2c-algo-bit.o: wrote %d bytes.\n",ret));
503                         if (ret < pmsg->len ) {
504                                 return (ret<0) ? ret : -EREMOTEIO;
505                         }
506                 }
507         }
508         i2c_stop(adap);
509         return num;
510 }
511
512 static u32 bit_func(struct i2c_adapter *adap)
513 {
514         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | 
515                I2C_FUNC_10BIT_ADDR | I2C_FUNC_PROTOCOL_MANGLING;
516 }
517
518
519 /* -----exported algorithm data: -------------------------------------  */
520
521 static struct i2c_algorithm i2c_bit_algo = {
522         .id             = I2C_ALGO_BIT,
523         .master_xfer    = bit_xfer,
524         .functionality  = bit_func,
525 };
526
527 /* 
528  * registering functions to load algorithms at runtime 
529  */
530 int i2c_bit_add_bus(struct i2c_adapter *adap)
531 {
532         struct i2c_algo_bit_data *bit_adap = adap->algo_data;
533
534         if (bit_test) {
535                 int ret = test_bus(bit_adap, adap->name);
536                 if (ret<0)
537                         return -ENODEV;
538         }
539
540         DEB2(dev_dbg(&adap->dev, "hw routines registered.\n"));
541
542         /* register new adapter to i2c module... */
543
544         adap->id |= i2c_bit_algo.id;
545         adap->algo = &i2c_bit_algo;
546
547         adap->timeout = 100;    /* default values, should       */
548         adap->retries = 3;      /* be replaced by defines       */
549
550         i2c_add_adapter(adap);
551         return 0;
552 }
553
554
555 int i2c_bit_del_bus(struct i2c_adapter *adap)
556 {
557         return i2c_del_adapter(adap);
558 }
559
560 EXPORT_SYMBOL(i2c_bit_add_bus);
561 EXPORT_SYMBOL(i2c_bit_del_bus);
562
563 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
564 MODULE_DESCRIPTION("I2C-Bus bit-banging algorithm");
565 MODULE_LICENSE("GPL");
566
567 module_param(bit_test, bool, 0);
568 module_param(i2c_debug, int, S_IRUGO | S_IWUSR);
569
570 MODULE_PARM_DESC(bit_test, "Test the lines of the bus to see if it is stuck");
571 MODULE_PARM_DESC(i2c_debug,
572                  "debug level - 0 off; 1 normal; 2,3 more verbose; 9 bit-protocol");