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