Merge git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty-2.6
[pandora-kernel.git] / drivers / i2c / algos / i2c-algo-pca.c
1 /*
2  *  i2c-algo-pca.c i2c driver algorithms for PCA9564 adapters
3  *    Copyright (C) 2004 Arcom Control Systems
4  *    Copyright (C) 2008 Pengutronix
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 #include <linux/kernel.h>
22 #include <linux/module.h>
23 #include <linux/moduleparam.h>
24 #include <linux/delay.h>
25 #include <linux/jiffies.h>
26 #include <linux/init.h>
27 #include <linux/errno.h>
28 #include <linux/i2c.h>
29 #include <linux/i2c-algo-pca.h>
30
31 #define DEB1(fmt, args...) do { if (i2c_debug >= 1)                     \
32                                  printk(KERN_DEBUG fmt, ## args); } while (0)
33 #define DEB2(fmt, args...) do { if (i2c_debug >= 2)                     \
34                                  printk(KERN_DEBUG fmt, ## args); } while (0)
35 #define DEB3(fmt, args...) do { if (i2c_debug >= 3)                     \
36                                  printk(KERN_DEBUG fmt, ## args); } while (0)
37
38 static int i2c_debug;
39
40 #define pca_outw(adap, reg, val) adap->write_byte(adap->data, reg, val)
41 #define pca_inw(adap, reg) adap->read_byte(adap->data, reg)
42
43 #define pca_status(adap) pca_inw(adap, I2C_PCA_STA)
44 #define pca_clock(adap) adap->i2c_clock
45 #define pca_set_con(adap, val) pca_outw(adap, I2C_PCA_CON, val)
46 #define pca_get_con(adap) pca_inw(adap, I2C_PCA_CON)
47 #define pca_wait(adap) adap->wait_for_completion(adap->data)
48 #define pca_reset(adap) adap->reset_chip(adap->data)
49
50 static void pca9665_reset(void *pd)
51 {
52         struct i2c_algo_pca_data *adap = pd;
53         pca_outw(adap, I2C_PCA_INDPTR, I2C_PCA_IPRESET);
54         pca_outw(adap, I2C_PCA_IND, 0xA5);
55         pca_outw(adap, I2C_PCA_IND, 0x5A);
56 }
57
58 /*
59  * Generate a start condition on the i2c bus.
60  *
61  * returns after the start condition has occurred
62  */
63 static int pca_start(struct i2c_algo_pca_data *adap)
64 {
65         int sta = pca_get_con(adap);
66         DEB2("=== START\n");
67         sta |= I2C_PCA_CON_STA;
68         sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_SI);
69         pca_set_con(adap, sta);
70         return pca_wait(adap);
71 }
72
73 /*
74  * Generate a repeated start condition on the i2c bus
75  *
76  * return after the repeated start condition has occurred
77  */
78 static int pca_repeated_start(struct i2c_algo_pca_data *adap)
79 {
80         int sta = pca_get_con(adap);
81         DEB2("=== REPEATED START\n");
82         sta |= I2C_PCA_CON_STA;
83         sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_SI);
84         pca_set_con(adap, sta);
85         return pca_wait(adap);
86 }
87
88 /*
89  * Generate a stop condition on the i2c bus
90  *
91  * returns after the stop condition has been generated
92  *
93  * STOPs do not generate an interrupt or set the SI flag, since the
94  * part returns the idle state (0xf8). Hence we don't need to
95  * pca_wait here.
96  */
97 static void pca_stop(struct i2c_algo_pca_data *adap)
98 {
99         int sta = pca_get_con(adap);
100         DEB2("=== STOP\n");
101         sta |= I2C_PCA_CON_STO;
102         sta &= ~(I2C_PCA_CON_STA|I2C_PCA_CON_SI);
103         pca_set_con(adap, sta);
104 }
105
106 /*
107  * Send the slave address and R/W bit
108  *
109  * returns after the address has been sent
110  */
111 static int pca_address(struct i2c_algo_pca_data *adap,
112                         struct i2c_msg *msg)
113 {
114         int sta = pca_get_con(adap);
115         int addr;
116
117         addr = ( (0x7f & msg->addr) << 1 );
118         if (msg->flags & I2C_M_RD )
119                 addr |= 1;
120         DEB2("=== SLAVE ADDRESS %#04x+%c=%#04x\n",
121              msg->addr, msg->flags & I2C_M_RD ? 'R' : 'W', addr);
122
123         pca_outw(adap, I2C_PCA_DAT, addr);
124
125         sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_STA|I2C_PCA_CON_SI);
126         pca_set_con(adap, sta);
127
128         return pca_wait(adap);
129 }
130
131 /*
132  * Transmit a byte.
133  *
134  * Returns after the byte has been transmitted
135  */
136 static int pca_tx_byte(struct i2c_algo_pca_data *adap,
137                         __u8 b)
138 {
139         int sta = pca_get_con(adap);
140         DEB2("=== WRITE %#04x\n", b);
141         pca_outw(adap, I2C_PCA_DAT, b);
142
143         sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_STA|I2C_PCA_CON_SI);
144         pca_set_con(adap, sta);
145
146         return pca_wait(adap);
147 }
148
149 /*
150  * Receive a byte
151  *
152  * returns immediately.
153  */
154 static void pca_rx_byte(struct i2c_algo_pca_data *adap,
155                         __u8 *b, int ack)
156 {
157         *b = pca_inw(adap, I2C_PCA_DAT);
158         DEB2("=== READ %#04x %s\n", *b, ack ? "ACK" : "NACK");
159 }
160
161 /*
162  * Setup ACK or NACK for next received byte and wait for it to arrive.
163  *
164  * Returns after next byte has arrived.
165  */
166 static int pca_rx_ack(struct i2c_algo_pca_data *adap,
167                        int ack)
168 {
169         int sta = pca_get_con(adap);
170
171         sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_STA|I2C_PCA_CON_SI|I2C_PCA_CON_AA);
172
173         if ( ack )
174                 sta |= I2C_PCA_CON_AA;
175
176         pca_set_con(adap, sta);
177         return pca_wait(adap);
178 }
179
180 static int pca_xfer(struct i2c_adapter *i2c_adap,
181                     struct i2c_msg *msgs,
182                     int num)
183 {
184         struct i2c_algo_pca_data *adap = i2c_adap->algo_data;
185         struct i2c_msg *msg = NULL;
186         int curmsg;
187         int numbytes = 0;
188         int state;
189         int ret;
190         int completed = 1;
191         unsigned long timeout = jiffies + i2c_adap->timeout;
192
193         while ((state = pca_status(adap)) != 0xf8) {
194                 if (time_before(jiffies, timeout)) {
195                         msleep(10);
196                 } else {
197                         dev_dbg(&i2c_adap->dev, "bus is not idle. status is "
198                                 "%#04x\n", state);
199                         return -EAGAIN;
200                 }
201         }
202
203         DEB1("{{{ XFER %d messages\n", num);
204
205         if (i2c_debug>=2) {
206                 for (curmsg = 0; curmsg < num; curmsg++) {
207                         int addr, i;
208                         msg = &msgs[curmsg];
209
210                         addr = (0x7f & msg->addr) ;
211
212                         if (msg->flags & I2C_M_RD )
213                                 printk(KERN_INFO "    [%02d] RD %d bytes from %#02x [%#02x, ...]\n",
214                                        curmsg, msg->len, addr, (addr<<1) | 1);
215                         else {
216                                 printk(KERN_INFO "    [%02d] WR %d bytes to %#02x [%#02x%s",
217                                        curmsg, msg->len, addr, addr<<1,
218                                        msg->len == 0 ? "" : ", ");
219                                 for(i=0; i < msg->len; i++)
220                                         printk("%#04x%s", msg->buf[i], i == msg->len - 1 ? "" : ", ");
221                                 printk("]\n");
222                         }
223                 }
224         }
225
226         curmsg = 0;
227         ret = -EREMOTEIO;
228         while (curmsg < num) {
229                 state = pca_status(adap);
230
231                 DEB3("STATE is 0x%02x\n", state);
232                 msg = &msgs[curmsg];
233
234                 switch (state) {
235                 case 0xf8: /* On reset or stop the bus is idle */
236                         completed = pca_start(adap);
237                         break;
238
239                 case 0x08: /* A START condition has been transmitted */
240                 case 0x10: /* A repeated start condition has been transmitted */
241                         completed = pca_address(adap, msg);
242                         break;
243
244                 case 0x18: /* SLA+W has been transmitted; ACK has been received */
245                 case 0x28: /* Data byte in I2CDAT has been transmitted; ACK has been received */
246                         if (numbytes < msg->len) {
247                                 completed = pca_tx_byte(adap,
248                                                         msg->buf[numbytes]);
249                                 numbytes++;
250                                 break;
251                         }
252                         curmsg++; numbytes = 0;
253                         if (curmsg == num)
254                                 pca_stop(adap);
255                         else
256                                 completed = pca_repeated_start(adap);
257                         break;
258
259                 case 0x20: /* SLA+W has been transmitted; NOT ACK has been received */
260                         DEB2("NOT ACK received after SLA+W\n");
261                         pca_stop(adap);
262                         goto out;
263
264                 case 0x40: /* SLA+R has been transmitted; ACK has been received */
265                         completed = pca_rx_ack(adap, msg->len > 1);
266                         break;
267
268                 case 0x50: /* Data bytes has been received; ACK has been returned */
269                         if (numbytes < msg->len) {
270                                 pca_rx_byte(adap, &msg->buf[numbytes], 1);
271                                 numbytes++;
272                                 completed = pca_rx_ack(adap,
273                                                        numbytes < msg->len - 1);
274                                 break;
275                         }
276                         curmsg++; numbytes = 0;
277                         if (curmsg == num)
278                                 pca_stop(adap);
279                         else
280                                 completed = pca_repeated_start(adap);
281                         break;
282
283                 case 0x48: /* SLA+R has been transmitted; NOT ACK has been received */
284                         DEB2("NOT ACK received after SLA+R\n");
285                         pca_stop(adap);
286                         goto out;
287
288                 case 0x30: /* Data byte in I2CDAT has been transmitted; NOT ACK has been received */
289                         DEB2("NOT ACK received after data byte\n");
290                         pca_stop(adap);
291                         goto out;
292
293                 case 0x38: /* Arbitration lost during SLA+W, SLA+R or data bytes */
294                         DEB2("Arbitration lost\n");
295                         /*
296                          * The PCA9564 data sheet (2006-09-01) says "A
297                          * START condition will be transmitted when the
298                          * bus becomes free (STOP or SCL and SDA high)"
299                          * when the STA bit is set (p. 11).
300                          *
301                          * In case this won't work, try pca_reset()
302                          * instead.
303                          */
304                         pca_start(adap);
305                         goto out;
306
307                 case 0x58: /* Data byte has been received; NOT ACK has been returned */
308                         if ( numbytes == msg->len - 1 ) {
309                                 pca_rx_byte(adap, &msg->buf[numbytes], 0);
310                                 curmsg++; numbytes = 0;
311                                 if (curmsg == num)
312                                         pca_stop(adap);
313                                 else
314                                         completed = pca_repeated_start(adap);
315                         } else {
316                                 DEB2("NOT ACK sent after data byte received. "
317                                      "Not final byte. numbytes %d. len %d\n",
318                                      numbytes, msg->len);
319                                 pca_stop(adap);
320                                 goto out;
321                         }
322                         break;
323                 case 0x70: /* Bus error - SDA stuck low */
324                         DEB2("BUS ERROR - SDA Stuck low\n");
325                         pca_reset(adap);
326                         goto out;
327                 case 0x90: /* Bus error - SCL stuck low */
328                         DEB2("BUS ERROR - SCL Stuck low\n");
329                         pca_reset(adap);
330                         goto out;
331                 case 0x00: /* Bus error during master or slave mode due to illegal START or STOP condition */
332                         DEB2("BUS ERROR - Illegal START or STOP\n");
333                         pca_reset(adap);
334                         goto out;
335                 default:
336                         dev_err(&i2c_adap->dev, "unhandled SIO state 0x%02x\n", state);
337                         break;
338                 }
339
340                 if (!completed)
341                         goto out;
342         }
343
344         ret = curmsg;
345  out:
346         DEB1("}}} transfered %d/%d messages. "
347              "status is %#04x. control is %#04x\n",
348              curmsg, num, pca_status(adap),
349              pca_get_con(adap));
350         return ret;
351 }
352
353 static u32 pca_func(struct i2c_adapter *adap)
354 {
355         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
356 }
357
358 static const struct i2c_algorithm pca_algo = {
359         .master_xfer    = pca_xfer,
360         .functionality  = pca_func,
361 };
362
363 static unsigned int pca_probe_chip(struct i2c_adapter *adap)
364 {
365         struct i2c_algo_pca_data *pca_data = adap->algo_data;
366         /* The trick here is to check if there is an indirect register
367          * available. If there is one, we will read the value we first
368          * wrote on I2C_PCA_IADR. Otherwise, we will read the last value
369          * we wrote on I2C_PCA_ADR
370          */
371         pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_IADR);
372         pca_outw(pca_data, I2C_PCA_IND, 0xAA);
373         pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_ITO);
374         pca_outw(pca_data, I2C_PCA_IND, 0x00);
375         pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_IADR);
376         if (pca_inw(pca_data, I2C_PCA_IND) == 0xAA) {
377                 printk(KERN_INFO "%s: PCA9665 detected.\n", adap->name);
378                 return I2C_PCA_CHIP_9665;
379         } else {
380                 printk(KERN_INFO "%s: PCA9564 detected.\n", adap->name);
381                 return I2C_PCA_CHIP_9564;
382         }
383 }
384
385 static int pca_init(struct i2c_adapter *adap)
386 {
387         struct i2c_algo_pca_data *pca_data = adap->algo_data;
388
389         adap->algo = &pca_algo;
390
391         if (pca_probe_chip(adap) == I2C_PCA_CHIP_9564) {
392                 static int freqs[] = {330, 288, 217, 146, 88, 59, 44, 36};
393                 int clock;
394
395                 if (pca_data->i2c_clock > 7) {
396                         switch (pca_data->i2c_clock) {
397                         case 330000:
398                                 pca_data->i2c_clock = I2C_PCA_CON_330kHz;
399                                 break;
400                         case 288000:
401                                 pca_data->i2c_clock = I2C_PCA_CON_288kHz;
402                                 break;
403                         case 217000:
404                                 pca_data->i2c_clock = I2C_PCA_CON_217kHz;
405                                 break;
406                         case 146000:
407                                 pca_data->i2c_clock = I2C_PCA_CON_146kHz;
408                                 break;
409                         case 88000:
410                                 pca_data->i2c_clock = I2C_PCA_CON_88kHz;
411                                 break;
412                         case 59000:
413                                 pca_data->i2c_clock = I2C_PCA_CON_59kHz;
414                                 break;
415                         case 44000:
416                                 pca_data->i2c_clock = I2C_PCA_CON_44kHz;
417                                 break;
418                         case 36000:
419                                 pca_data->i2c_clock = I2C_PCA_CON_36kHz;
420                                 break;
421                         default:
422                                 printk(KERN_WARNING
423                                         "%s: Invalid I2C clock speed selected."
424                                         " Using default 59kHz.\n", adap->name);
425                         pca_data->i2c_clock = I2C_PCA_CON_59kHz;
426                         }
427                 } else {
428                         printk(KERN_WARNING "%s: "
429                                 "Choosing the clock frequency based on "
430                                 "index is deprecated."
431                                 " Use the nominal frequency.\n", adap->name);
432                 }
433
434                 pca_reset(pca_data);
435
436                 clock = pca_clock(pca_data);
437                 printk(KERN_INFO "%s: Clock frequency is %dkHz\n",
438                      adap->name, freqs[clock]);
439
440                 pca_set_con(pca_data, I2C_PCA_CON_ENSIO | clock);
441         } else {
442                 int clock;
443                 int mode;
444                 int tlow, thi;
445                 /* Values can be found on PCA9665 datasheet section 7.3.2.6 */
446                 int min_tlow, min_thi;
447                 /* These values are the maximum raise and fall values allowed
448                  * by the I2C operation mode (Standard, Fast or Fast+)
449                  * They are used (added) below to calculate the clock dividers
450                  * of PCA9665. Note that they are slightly different of the
451                  * real maximum, to allow the change on mode exactly on the
452                  * maximum clock rate for each mode
453                  */
454                 int raise_fall_time;
455
456                 /* Ignore the reset function from the module,
457                  * we can use the parallel bus reset
458                  */
459                 pca_data->reset_chip = pca9665_reset;
460
461                 if (pca_data->i2c_clock > 1265800) {
462                         printk(KERN_WARNING "%s: I2C clock speed too high."
463                                 " Using 1265.8kHz.\n", adap->name);
464                         pca_data->i2c_clock = 1265800;
465                 }
466
467                 if (pca_data->i2c_clock < 60300) {
468                         printk(KERN_WARNING "%s: I2C clock speed too low."
469                                 " Using 60.3kHz.\n", adap->name);
470                         pca_data->i2c_clock = 60300;
471                 }
472
473                 /* To avoid integer overflow, use clock/100 for calculations */
474                 clock = pca_clock(pca_data) / 100;
475
476                 if (pca_data->i2c_clock > 10000) {
477                         mode = I2C_PCA_MODE_TURBO;
478                         min_tlow = 14;
479                         min_thi  = 5;
480                         raise_fall_time = 22; /* Raise 11e-8s, Fall 11e-8s */
481                 } else if (pca_data->i2c_clock > 4000) {
482                         mode = I2C_PCA_MODE_FASTP;
483                         min_tlow = 17;
484                         min_thi  = 9;
485                         raise_fall_time = 22; /* Raise 11e-8s, Fall 11e-8s */
486                 } else if (pca_data->i2c_clock > 1000) {
487                         mode = I2C_PCA_MODE_FAST;
488                         min_tlow = 44;
489                         min_thi  = 20;
490                         raise_fall_time = 58; /* Raise 29e-8s, Fall 29e-8s */
491                 } else {
492                         mode = I2C_PCA_MODE_STD;
493                         min_tlow = 157;
494                         min_thi  = 134;
495                         raise_fall_time = 127; /* Raise 29e-8s, Fall 98e-8s */
496                 }
497
498                 /* The minimum clock that respects the thi/tlow = 134/157 is
499                  * 64800 Hz. Below that, we have to fix the tlow to 255 and
500                  * calculate the thi factor.
501                  */
502                 if (clock < 648) {
503                         tlow = 255;
504                         thi = 1000000 - clock * raise_fall_time;
505                         thi /= (I2C_PCA_OSC_PER * clock) - tlow;
506                 } else {
507                         tlow = (1000000 - clock * raise_fall_time) * min_tlow;
508                         tlow /= I2C_PCA_OSC_PER * clock * (min_thi + min_tlow);
509                         thi = tlow * min_thi / min_tlow;
510                 }
511
512                 pca_reset(pca_data);
513
514                 printk(KERN_INFO
515                      "%s: Clock frequency is %dHz\n", adap->name, clock * 100);
516
517                 pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_IMODE);
518                 pca_outw(pca_data, I2C_PCA_IND, mode);
519                 pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_ISCLL);
520                 pca_outw(pca_data, I2C_PCA_IND, tlow);
521                 pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_ISCLH);
522                 pca_outw(pca_data, I2C_PCA_IND, thi);
523
524                 pca_set_con(pca_data, I2C_PCA_CON_ENSIO);
525         }
526         udelay(500); /* 500 us for oscilator to stabilise */
527
528         return 0;
529 }
530
531 /*
532  * registering functions to load algorithms at runtime
533  */
534 int i2c_pca_add_bus(struct i2c_adapter *adap)
535 {
536         int rval;
537
538         rval = pca_init(adap);
539         if (rval)
540                 return rval;
541
542         return i2c_add_adapter(adap);
543 }
544 EXPORT_SYMBOL(i2c_pca_add_bus);
545
546 int i2c_pca_add_numbered_bus(struct i2c_adapter *adap)
547 {
548         int rval;
549
550         rval = pca_init(adap);
551         if (rval)
552                 return rval;
553
554         return i2c_add_numbered_adapter(adap);
555 }
556 EXPORT_SYMBOL(i2c_pca_add_numbered_bus);
557
558 MODULE_AUTHOR("Ian Campbell <icampbell@arcom.com>, "
559         "Wolfram Sang <w.sang@pengutronix.de>");
560 MODULE_DESCRIPTION("I2C-Bus PCA9564/PCA9665 algorithm");
561 MODULE_LICENSE("GPL");
562
563 module_param(i2c_debug, int, 0);