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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
38static 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
50static 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 */
63static 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 */
78static 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 */
97static 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 */
111static 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 */
136static 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 */
154static 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 */
166static 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
180static 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("}}} transferred %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
353static u32 pca_func(struct i2c_adapter *adap)
354{
355 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
356}
357
358static const struct i2c_algorithm pca_algo = {
359 .master_xfer = pca_xfer,
360 .functionality = pca_func,
361};
362
363static 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
385static 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 */
534int 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}
544EXPORT_SYMBOL(i2c_pca_add_bus);
545
546int 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}
556EXPORT_SYMBOL(i2c_pca_add_numbered_bus);
557
558MODULE_AUTHOR("Ian Campbell <icampbell@arcom.com>, "
559 "Wolfram Sang <w.sang@pengutronix.de>");
560MODULE_DESCRIPTION("I2C-Bus PCA9564/PCA9665 algorithm");
561MODULE_LICENSE("GPL");
562
563module_param(i2c_debug, int, 0);
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., 51 Franklin Street, Fifth Floor, Boston,
19 * MA 02110-1301 USA.
20 */
21
22#include <linux/kernel.h>
23#include <linux/module.h>
24#include <linux/moduleparam.h>
25#include <linux/delay.h>
26#include <linux/jiffies.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
38static 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
49static void pca_reset(struct i2c_algo_pca_data *adap)
50{
51 if (adap->chip == I2C_PCA_CHIP_9665) {
52 /* Ignore the reset function from the module,
53 * we can use the parallel bus reset.
54 */
55 pca_outw(adap, I2C_PCA_INDPTR, I2C_PCA_IPRESET);
56 pca_outw(adap, I2C_PCA_IND, 0xA5);
57 pca_outw(adap, I2C_PCA_IND, 0x5A);
58 } else {
59 adap->reset_chip(adap->data);
60 }
61}
62
63/*
64 * Generate a start condition on the i2c bus.
65 *
66 * returns after the start condition has occurred
67 */
68static int pca_start(struct i2c_algo_pca_data *adap)
69{
70 int sta = pca_get_con(adap);
71 DEB2("=== START\n");
72 sta |= I2C_PCA_CON_STA;
73 sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_SI);
74 pca_set_con(adap, sta);
75 return pca_wait(adap);
76}
77
78/*
79 * Generate a repeated start condition on the i2c bus
80 *
81 * return after the repeated start condition has occurred
82 */
83static int pca_repeated_start(struct i2c_algo_pca_data *adap)
84{
85 int sta = pca_get_con(adap);
86 DEB2("=== REPEATED START\n");
87 sta |= I2C_PCA_CON_STA;
88 sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_SI);
89 pca_set_con(adap, sta);
90 return pca_wait(adap);
91}
92
93/*
94 * Generate a stop condition on the i2c bus
95 *
96 * returns after the stop condition has been generated
97 *
98 * STOPs do not generate an interrupt or set the SI flag, since the
99 * part returns the idle state (0xf8). Hence we don't need to
100 * pca_wait here.
101 */
102static void pca_stop(struct i2c_algo_pca_data *adap)
103{
104 int sta = pca_get_con(adap);
105 DEB2("=== STOP\n");
106 sta |= I2C_PCA_CON_STO;
107 sta &= ~(I2C_PCA_CON_STA|I2C_PCA_CON_SI);
108 pca_set_con(adap, sta);
109}
110
111/*
112 * Send the slave address and R/W bit
113 *
114 * returns after the address has been sent
115 */
116static int pca_address(struct i2c_algo_pca_data *adap,
117 struct i2c_msg *msg)
118{
119 int sta = pca_get_con(adap);
120 int addr;
121
122 addr = ((0x7f & msg->addr) << 1);
123 if (msg->flags & I2C_M_RD)
124 addr |= 1;
125 DEB2("=== SLAVE ADDRESS %#04x+%c=%#04x\n",
126 msg->addr, msg->flags & I2C_M_RD ? 'R' : 'W', addr);
127
128 pca_outw(adap, I2C_PCA_DAT, addr);
129
130 sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_STA|I2C_PCA_CON_SI);
131 pca_set_con(adap, sta);
132
133 return pca_wait(adap);
134}
135
136/*
137 * Transmit a byte.
138 *
139 * Returns after the byte has been transmitted
140 */
141static int pca_tx_byte(struct i2c_algo_pca_data *adap,
142 __u8 b)
143{
144 int sta = pca_get_con(adap);
145 DEB2("=== WRITE %#04x\n", b);
146 pca_outw(adap, I2C_PCA_DAT, b);
147
148 sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_STA|I2C_PCA_CON_SI);
149 pca_set_con(adap, sta);
150
151 return pca_wait(adap);
152}
153
154/*
155 * Receive a byte
156 *
157 * returns immediately.
158 */
159static void pca_rx_byte(struct i2c_algo_pca_data *adap,
160 __u8 *b, int ack)
161{
162 *b = pca_inw(adap, I2C_PCA_DAT);
163 DEB2("=== READ %#04x %s\n", *b, ack ? "ACK" : "NACK");
164}
165
166/*
167 * Setup ACK or NACK for next received byte and wait for it to arrive.
168 *
169 * Returns after next byte has arrived.
170 */
171static int pca_rx_ack(struct i2c_algo_pca_data *adap,
172 int ack)
173{
174 int sta = pca_get_con(adap);
175
176 sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_STA|I2C_PCA_CON_SI|I2C_PCA_CON_AA);
177
178 if (ack)
179 sta |= I2C_PCA_CON_AA;
180
181 pca_set_con(adap, sta);
182 return pca_wait(adap);
183}
184
185static int pca_xfer(struct i2c_adapter *i2c_adap,
186 struct i2c_msg *msgs,
187 int num)
188{
189 struct i2c_algo_pca_data *adap = i2c_adap->algo_data;
190 struct i2c_msg *msg = NULL;
191 int curmsg;
192 int numbytes = 0;
193 int state;
194 int ret;
195 int completed = 1;
196 unsigned long timeout = jiffies + i2c_adap->timeout;
197
198 while ((state = pca_status(adap)) != 0xf8) {
199 if (time_before(jiffies, timeout)) {
200 msleep(10);
201 } else {
202 dev_dbg(&i2c_adap->dev, "bus is not idle. status is "
203 "%#04x\n", state);
204 return -EBUSY;
205 }
206 }
207
208 DEB1("{{{ XFER %d messages\n", num);
209
210 if (i2c_debug >= 2) {
211 for (curmsg = 0; curmsg < num; curmsg++) {
212 int addr, i;
213 msg = &msgs[curmsg];
214
215 addr = (0x7f & msg->addr) ;
216
217 if (msg->flags & I2C_M_RD)
218 printk(KERN_INFO " [%02d] RD %d bytes from %#02x [%#02x, ...]\n",
219 curmsg, msg->len, addr, (addr << 1) | 1);
220 else {
221 printk(KERN_INFO " [%02d] WR %d bytes to %#02x [%#02x%s",
222 curmsg, msg->len, addr, addr << 1,
223 msg->len == 0 ? "" : ", ");
224 for (i = 0; i < msg->len; i++)
225 printk("%#04x%s", msg->buf[i], i == msg->len - 1 ? "" : ", ");
226 printk("]\n");
227 }
228 }
229 }
230
231 curmsg = 0;
232 ret = -EIO;
233 while (curmsg < num) {
234 state = pca_status(adap);
235
236 DEB3("STATE is 0x%02x\n", state);
237 msg = &msgs[curmsg];
238
239 switch (state) {
240 case 0xf8: /* On reset or stop the bus is idle */
241 completed = pca_start(adap);
242 break;
243
244 case 0x08: /* A START condition has been transmitted */
245 case 0x10: /* A repeated start condition has been transmitted */
246 completed = pca_address(adap, msg);
247 break;
248
249 case 0x18: /* SLA+W has been transmitted; ACK has been received */
250 case 0x28: /* Data byte in I2CDAT has been transmitted; ACK has been received */
251 if (numbytes < msg->len) {
252 completed = pca_tx_byte(adap,
253 msg->buf[numbytes]);
254 numbytes++;
255 break;
256 }
257 curmsg++; numbytes = 0;
258 if (curmsg == num)
259 pca_stop(adap);
260 else
261 completed = pca_repeated_start(adap);
262 break;
263
264 case 0x20: /* SLA+W has been transmitted; NOT ACK has been received */
265 DEB2("NOT ACK received after SLA+W\n");
266 pca_stop(adap);
267 ret = -ENXIO;
268 goto out;
269
270 case 0x40: /* SLA+R has been transmitted; ACK has been received */
271 completed = pca_rx_ack(adap, msg->len > 1);
272 break;
273
274 case 0x50: /* Data bytes has been received; ACK has been returned */
275 if (numbytes < msg->len) {
276 pca_rx_byte(adap, &msg->buf[numbytes], 1);
277 numbytes++;
278 completed = pca_rx_ack(adap,
279 numbytes < msg->len - 1);
280 break;
281 }
282 curmsg++; numbytes = 0;
283 if (curmsg == num)
284 pca_stop(adap);
285 else
286 completed = pca_repeated_start(adap);
287 break;
288
289 case 0x48: /* SLA+R has been transmitted; NOT ACK has been received */
290 DEB2("NOT ACK received after SLA+R\n");
291 pca_stop(adap);
292 ret = -ENXIO;
293 goto out;
294
295 case 0x30: /* Data byte in I2CDAT has been transmitted; NOT ACK has been received */
296 DEB2("NOT ACK received after data byte\n");
297 pca_stop(adap);
298 goto out;
299
300 case 0x38: /* Arbitration lost during SLA+W, SLA+R or data bytes */
301 DEB2("Arbitration lost\n");
302 /*
303 * The PCA9564 data sheet (2006-09-01) says "A
304 * START condition will be transmitted when the
305 * bus becomes free (STOP or SCL and SDA high)"
306 * when the STA bit is set (p. 11).
307 *
308 * In case this won't work, try pca_reset()
309 * instead.
310 */
311 pca_start(adap);
312 goto out;
313
314 case 0x58: /* Data byte has been received; NOT ACK has been returned */
315 if (numbytes == msg->len - 1) {
316 pca_rx_byte(adap, &msg->buf[numbytes], 0);
317 curmsg++; numbytes = 0;
318 if (curmsg == num)
319 pca_stop(adap);
320 else
321 completed = pca_repeated_start(adap);
322 } else {
323 DEB2("NOT ACK sent after data byte received. "
324 "Not final byte. numbytes %d. len %d\n",
325 numbytes, msg->len);
326 pca_stop(adap);
327 goto out;
328 }
329 break;
330 case 0x70: /* Bus error - SDA stuck low */
331 DEB2("BUS ERROR - SDA Stuck low\n");
332 pca_reset(adap);
333 goto out;
334 case 0x90: /* Bus error - SCL stuck low */
335 DEB2("BUS ERROR - SCL Stuck low\n");
336 pca_reset(adap);
337 goto out;
338 case 0x00: /* Bus error during master or slave mode due to illegal START or STOP condition */
339 DEB2("BUS ERROR - Illegal START or STOP\n");
340 pca_reset(adap);
341 goto out;
342 default:
343 dev_err(&i2c_adap->dev, "unhandled SIO state 0x%02x\n", state);
344 break;
345 }
346
347 if (!completed)
348 goto out;
349 }
350
351 ret = curmsg;
352 out:
353 DEB1("}}} transferred %d/%d messages. "
354 "status is %#04x. control is %#04x\n",
355 curmsg, num, pca_status(adap),
356 pca_get_con(adap));
357 return ret;
358}
359
360static u32 pca_func(struct i2c_adapter *adap)
361{
362 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
363}
364
365static const struct i2c_algorithm pca_algo = {
366 .master_xfer = pca_xfer,
367 .functionality = pca_func,
368};
369
370static unsigned int pca_probe_chip(struct i2c_adapter *adap)
371{
372 struct i2c_algo_pca_data *pca_data = adap->algo_data;
373 /* The trick here is to check if there is an indirect register
374 * available. If there is one, we will read the value we first
375 * wrote on I2C_PCA_IADR. Otherwise, we will read the last value
376 * we wrote on I2C_PCA_ADR
377 */
378 pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_IADR);
379 pca_outw(pca_data, I2C_PCA_IND, 0xAA);
380 pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_ITO);
381 pca_outw(pca_data, I2C_PCA_IND, 0x00);
382 pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_IADR);
383 if (pca_inw(pca_data, I2C_PCA_IND) == 0xAA) {
384 printk(KERN_INFO "%s: PCA9665 detected.\n", adap->name);
385 pca_data->chip = I2C_PCA_CHIP_9665;
386 } else {
387 printk(KERN_INFO "%s: PCA9564 detected.\n", adap->name);
388 pca_data->chip = I2C_PCA_CHIP_9564;
389 }
390 return pca_data->chip;
391}
392
393static int pca_init(struct i2c_adapter *adap)
394{
395 struct i2c_algo_pca_data *pca_data = adap->algo_data;
396
397 adap->algo = &pca_algo;
398
399 if (pca_probe_chip(adap) == I2C_PCA_CHIP_9564) {
400 static int freqs[] = {330, 288, 217, 146, 88, 59, 44, 36};
401 int clock;
402
403 if (pca_data->i2c_clock > 7) {
404 switch (pca_data->i2c_clock) {
405 case 330000:
406 pca_data->i2c_clock = I2C_PCA_CON_330kHz;
407 break;
408 case 288000:
409 pca_data->i2c_clock = I2C_PCA_CON_288kHz;
410 break;
411 case 217000:
412 pca_data->i2c_clock = I2C_PCA_CON_217kHz;
413 break;
414 case 146000:
415 pca_data->i2c_clock = I2C_PCA_CON_146kHz;
416 break;
417 case 88000:
418 pca_data->i2c_clock = I2C_PCA_CON_88kHz;
419 break;
420 case 59000:
421 pca_data->i2c_clock = I2C_PCA_CON_59kHz;
422 break;
423 case 44000:
424 pca_data->i2c_clock = I2C_PCA_CON_44kHz;
425 break;
426 case 36000:
427 pca_data->i2c_clock = I2C_PCA_CON_36kHz;
428 break;
429 default:
430 printk(KERN_WARNING
431 "%s: Invalid I2C clock speed selected."
432 " Using default 59kHz.\n", adap->name);
433 pca_data->i2c_clock = I2C_PCA_CON_59kHz;
434 }
435 } else {
436 printk(KERN_WARNING "%s: "
437 "Choosing the clock frequency based on "
438 "index is deprecated."
439 " Use the nominal frequency.\n", adap->name);
440 }
441
442 pca_reset(pca_data);
443
444 clock = pca_clock(pca_data);
445 printk(KERN_INFO "%s: Clock frequency is %dkHz\n",
446 adap->name, freqs[clock]);
447
448 pca_set_con(pca_data, I2C_PCA_CON_ENSIO | clock);
449 } else {
450 int clock;
451 int mode;
452 int tlow, thi;
453 /* Values can be found on PCA9665 datasheet section 7.3.2.6 */
454 int min_tlow, min_thi;
455 /* These values are the maximum raise and fall values allowed
456 * by the I2C operation mode (Standard, Fast or Fast+)
457 * They are used (added) below to calculate the clock dividers
458 * of PCA9665. Note that they are slightly different of the
459 * real maximum, to allow the change on mode exactly on the
460 * maximum clock rate for each mode
461 */
462 int raise_fall_time;
463
464 if (pca_data->i2c_clock > 1265800) {
465 printk(KERN_WARNING "%s: I2C clock speed too high."
466 " Using 1265.8kHz.\n", adap->name);
467 pca_data->i2c_clock = 1265800;
468 }
469
470 if (pca_data->i2c_clock < 60300) {
471 printk(KERN_WARNING "%s: I2C clock speed too low."
472 " Using 60.3kHz.\n", adap->name);
473 pca_data->i2c_clock = 60300;
474 }
475
476 /* To avoid integer overflow, use clock/100 for calculations */
477 clock = pca_clock(pca_data) / 100;
478
479 if (pca_data->i2c_clock > 1000000) {
480 mode = I2C_PCA_MODE_TURBO;
481 min_tlow = 14;
482 min_thi = 5;
483 raise_fall_time = 22; /* Raise 11e-8s, Fall 11e-8s */
484 } else if (pca_data->i2c_clock > 400000) {
485 mode = I2C_PCA_MODE_FASTP;
486 min_tlow = 17;
487 min_thi = 9;
488 raise_fall_time = 22; /* Raise 11e-8s, Fall 11e-8s */
489 } else if (pca_data->i2c_clock > 100000) {
490 mode = I2C_PCA_MODE_FAST;
491 min_tlow = 44;
492 min_thi = 20;
493 raise_fall_time = 58; /* Raise 29e-8s, Fall 29e-8s */
494 } else {
495 mode = I2C_PCA_MODE_STD;
496 min_tlow = 157;
497 min_thi = 134;
498 raise_fall_time = 127; /* Raise 29e-8s, Fall 98e-8s */
499 }
500
501 /* The minimum clock that respects the thi/tlow = 134/157 is
502 * 64800 Hz. Below that, we have to fix the tlow to 255 and
503 * calculate the thi factor.
504 */
505 if (clock < 648) {
506 tlow = 255;
507 thi = 1000000 - clock * raise_fall_time;
508 thi /= (I2C_PCA_OSC_PER * clock) - tlow;
509 } else {
510 tlow = (1000000 - clock * raise_fall_time) * min_tlow;
511 tlow /= I2C_PCA_OSC_PER * clock * (min_thi + min_tlow);
512 thi = tlow * min_thi / min_tlow;
513 }
514
515 pca_reset(pca_data);
516
517 printk(KERN_INFO
518 "%s: Clock frequency is %dHz\n", adap->name, clock * 100);
519
520 pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_IMODE);
521 pca_outw(pca_data, I2C_PCA_IND, mode);
522 pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_ISCLL);
523 pca_outw(pca_data, I2C_PCA_IND, tlow);
524 pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_ISCLH);
525 pca_outw(pca_data, I2C_PCA_IND, thi);
526
527 pca_set_con(pca_data, I2C_PCA_CON_ENSIO);
528 }
529 udelay(500); /* 500 us for oscilator to stabilise */
530
531 return 0;
532}
533
534/*
535 * registering functions to load algorithms at runtime
536 */
537int i2c_pca_add_bus(struct i2c_adapter *adap)
538{
539 int rval;
540
541 rval = pca_init(adap);
542 if (rval)
543 return rval;
544
545 return i2c_add_adapter(adap);
546}
547EXPORT_SYMBOL(i2c_pca_add_bus);
548
549int i2c_pca_add_numbered_bus(struct i2c_adapter *adap)
550{
551 int rval;
552
553 rval = pca_init(adap);
554 if (rval)
555 return rval;
556
557 return i2c_add_numbered_adapter(adap);
558}
559EXPORT_SYMBOL(i2c_pca_add_numbered_bus);
560
561MODULE_AUTHOR("Ian Campbell <icampbell@arcom.com>, "
562 "Wolfram Sang <w.sang@pengutronix.de>");
563MODULE_DESCRIPTION("I2C-Bus PCA9564/PCA9665 algorithm");
564MODULE_LICENSE("GPL");
565
566module_param(i2c_debug, int, 0);