treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157
[sfrench/cifs-2.6.git] / drivers / i2c / algos / i2c-algo-pca.c
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *  i2c-algo-pca.c i2c driver algorithms for PCA9564 adapters
4  *    Copyright (C) 2004 Arcom Control Systems
5  *    Copyright (C) 2008 Pengutronix
6  */
7
8 #include <linux/kernel.h>
9 #include <linux/module.h>
10 #include <linux/moduleparam.h>
11 #include <linux/delay.h>
12 #include <linux/jiffies.h>
13 #include <linux/errno.h>
14 #include <linux/i2c.h>
15 #include <linux/i2c-algo-pca.h>
16
17 #define DEB1(fmt, args...) do { if (i2c_debug >= 1)                     \
18                                  printk(KERN_DEBUG fmt, ## args); } while (0)
19 #define DEB2(fmt, args...) do { if (i2c_debug >= 2)                     \
20                                  printk(KERN_DEBUG fmt, ## args); } while (0)
21 #define DEB3(fmt, args...) do { if (i2c_debug >= 3)                     \
22                                  printk(KERN_DEBUG fmt, ## args); } while (0)
23
24 static int i2c_debug;
25
26 #define pca_outw(adap, reg, val) adap->write_byte(adap->data, reg, val)
27 #define pca_inw(adap, reg) adap->read_byte(adap->data, reg)
28
29 #define pca_status(adap) pca_inw(adap, I2C_PCA_STA)
30 #define pca_clock(adap) adap->i2c_clock
31 #define pca_set_con(adap, val) pca_outw(adap, I2C_PCA_CON, val)
32 #define pca_get_con(adap) pca_inw(adap, I2C_PCA_CON)
33 #define pca_wait(adap) adap->wait_for_completion(adap->data)
34
35 static void pca_reset(struct i2c_algo_pca_data *adap)
36 {
37         if (adap->chip == I2C_PCA_CHIP_9665) {
38                 /* Ignore the reset function from the module,
39                  * we can use the parallel bus reset.
40                  */
41                 pca_outw(adap, I2C_PCA_INDPTR, I2C_PCA_IPRESET);
42                 pca_outw(adap, I2C_PCA_IND, 0xA5);
43                 pca_outw(adap, I2C_PCA_IND, 0x5A);
44         } else {
45                 adap->reset_chip(adap->data);
46         }
47 }
48
49 /*
50  * Generate a start condition on the i2c bus.
51  *
52  * returns after the start condition has occurred
53  */
54 static int pca_start(struct i2c_algo_pca_data *adap)
55 {
56         int sta = pca_get_con(adap);
57         DEB2("=== START\n");
58         sta |= I2C_PCA_CON_STA;
59         sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_SI);
60         pca_set_con(adap, sta);
61         return pca_wait(adap);
62 }
63
64 /*
65  * Generate a repeated start condition on the i2c bus
66  *
67  * return after the repeated start condition has occurred
68  */
69 static int pca_repeated_start(struct i2c_algo_pca_data *adap)
70 {
71         int sta = pca_get_con(adap);
72         DEB2("=== REPEATED START\n");
73         sta |= I2C_PCA_CON_STA;
74         sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_SI);
75         pca_set_con(adap, sta);
76         return pca_wait(adap);
77 }
78
79 /*
80  * Generate a stop condition on the i2c bus
81  *
82  * returns after the stop condition has been generated
83  *
84  * STOPs do not generate an interrupt or set the SI flag, since the
85  * part returns the idle state (0xf8). Hence we don't need to
86  * pca_wait here.
87  */
88 static void pca_stop(struct i2c_algo_pca_data *adap)
89 {
90         int sta = pca_get_con(adap);
91         DEB2("=== STOP\n");
92         sta |= I2C_PCA_CON_STO;
93         sta &= ~(I2C_PCA_CON_STA|I2C_PCA_CON_SI);
94         pca_set_con(adap, sta);
95 }
96
97 /*
98  * Send the slave address and R/W bit
99  *
100  * returns after the address has been sent
101  */
102 static int pca_address(struct i2c_algo_pca_data *adap,
103                        struct i2c_msg *msg)
104 {
105         int sta = pca_get_con(adap);
106         int addr = i2c_8bit_addr_from_msg(msg);
107
108         DEB2("=== SLAVE ADDRESS %#04x+%c=%#04x\n",
109              msg->addr, msg->flags & I2C_M_RD ? 'R' : 'W', addr);
110
111         pca_outw(adap, I2C_PCA_DAT, addr);
112
113         sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_STA|I2C_PCA_CON_SI);
114         pca_set_con(adap, sta);
115
116         return pca_wait(adap);
117 }
118
119 /*
120  * Transmit a byte.
121  *
122  * Returns after the byte has been transmitted
123  */
124 static int pca_tx_byte(struct i2c_algo_pca_data *adap,
125                        __u8 b)
126 {
127         int sta = pca_get_con(adap);
128         DEB2("=== WRITE %#04x\n", b);
129         pca_outw(adap, I2C_PCA_DAT, b);
130
131         sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_STA|I2C_PCA_CON_SI);
132         pca_set_con(adap, sta);
133
134         return pca_wait(adap);
135 }
136
137 /*
138  * Receive a byte
139  *
140  * returns immediately.
141  */
142 static void pca_rx_byte(struct i2c_algo_pca_data *adap,
143                         __u8 *b, int ack)
144 {
145         *b = pca_inw(adap, I2C_PCA_DAT);
146         DEB2("=== READ %#04x %s\n", *b, ack ? "ACK" : "NACK");
147 }
148
149 /*
150  * Setup ACK or NACK for next received byte and wait for it to arrive.
151  *
152  * Returns after next byte has arrived.
153  */
154 static int pca_rx_ack(struct i2c_algo_pca_data *adap,
155                       int ack)
156 {
157         int sta = pca_get_con(adap);
158
159         sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_STA|I2C_PCA_CON_SI|I2C_PCA_CON_AA);
160
161         if (ack)
162                 sta |= I2C_PCA_CON_AA;
163
164         pca_set_con(adap, sta);
165         return pca_wait(adap);
166 }
167
168 static int pca_xfer(struct i2c_adapter *i2c_adap,
169                     struct i2c_msg *msgs,
170                     int num)
171 {
172         struct i2c_algo_pca_data *adap = i2c_adap->algo_data;
173         struct i2c_msg *msg = NULL;
174         int curmsg;
175         int numbytes = 0;
176         int state;
177         int ret;
178         int completed = 1;
179         unsigned long timeout = jiffies + i2c_adap->timeout;
180
181         while ((state = pca_status(adap)) != 0xf8) {
182                 if (time_before(jiffies, timeout)) {
183                         msleep(10);
184                 } else {
185                         dev_dbg(&i2c_adap->dev, "bus is not idle. status is "
186                                 "%#04x\n", state);
187                         return -EBUSY;
188                 }
189         }
190
191         DEB1("{{{ XFER %d messages\n", num);
192
193         if (i2c_debug >= 2) {
194                 for (curmsg = 0; curmsg < num; curmsg++) {
195                         int addr, i;
196                         msg = &msgs[curmsg];
197
198                         addr = (0x7f & msg->addr) ;
199
200                         if (msg->flags & I2C_M_RD)
201                                 printk(KERN_INFO "    [%02d] RD %d bytes from %#02x [%#02x, ...]\n",
202                                        curmsg, msg->len, addr, (addr << 1) | 1);
203                         else {
204                                 printk(KERN_INFO "    [%02d] WR %d bytes to %#02x [%#02x%s",
205                                        curmsg, msg->len, addr, addr << 1,
206                                        msg->len == 0 ? "" : ", ");
207                                 for (i = 0; i < msg->len; i++)
208                                         printk("%#04x%s", msg->buf[i], i == msg->len - 1 ? "" : ", ");
209                                 printk("]\n");
210                         }
211                 }
212         }
213
214         curmsg = 0;
215         ret = -EIO;
216         while (curmsg < num) {
217                 state = pca_status(adap);
218
219                 DEB3("STATE is 0x%02x\n", state);
220                 msg = &msgs[curmsg];
221
222                 switch (state) {
223                 case 0xf8: /* On reset or stop the bus is idle */
224                         completed = pca_start(adap);
225                         break;
226
227                 case 0x08: /* A START condition has been transmitted */
228                 case 0x10: /* A repeated start condition has been transmitted */
229                         completed = pca_address(adap, msg);
230                         break;
231
232                 case 0x18: /* SLA+W has been transmitted; ACK has been received */
233                 case 0x28: /* Data byte in I2CDAT has been transmitted; ACK has been received */
234                         if (numbytes < msg->len) {
235                                 completed = pca_tx_byte(adap,
236                                                         msg->buf[numbytes]);
237                                 numbytes++;
238                                 break;
239                         }
240                         curmsg++; numbytes = 0;
241                         if (curmsg == num)
242                                 pca_stop(adap);
243                         else
244                                 completed = pca_repeated_start(adap);
245                         break;
246
247                 case 0x20: /* SLA+W has been transmitted; NOT ACK has been received */
248                         DEB2("NOT ACK received after SLA+W\n");
249                         pca_stop(adap);
250                         ret = -ENXIO;
251                         goto out;
252
253                 case 0x40: /* SLA+R has been transmitted; ACK has been received */
254                         completed = pca_rx_ack(adap, msg->len > 1);
255                         break;
256
257                 case 0x50: /* Data bytes has been received; ACK has been returned */
258                         if (numbytes < msg->len) {
259                                 pca_rx_byte(adap, &msg->buf[numbytes], 1);
260                                 numbytes++;
261                                 completed = pca_rx_ack(adap,
262                                                        numbytes < msg->len - 1);
263                                 break;
264                         }
265                         curmsg++; numbytes = 0;
266                         if (curmsg == num)
267                                 pca_stop(adap);
268                         else
269                                 completed = pca_repeated_start(adap);
270                         break;
271
272                 case 0x48: /* SLA+R has been transmitted; NOT ACK has been received */
273                         DEB2("NOT ACK received after SLA+R\n");
274                         pca_stop(adap);
275                         ret = -ENXIO;
276                         goto out;
277
278                 case 0x30: /* Data byte in I2CDAT has been transmitted; NOT ACK has been received */
279                         DEB2("NOT ACK received after data byte\n");
280                         pca_stop(adap);
281                         goto out;
282
283                 case 0x38: /* Arbitration lost during SLA+W, SLA+R or data bytes */
284                         DEB2("Arbitration lost\n");
285                         /*
286                          * The PCA9564 data sheet (2006-09-01) says "A
287                          * START condition will be transmitted when the
288                          * bus becomes free (STOP or SCL and SDA high)"
289                          * when the STA bit is set (p. 11).
290                          *
291                          * In case this won't work, try pca_reset()
292                          * instead.
293                          */
294                         pca_start(adap);
295                         goto out;
296
297                 case 0x58: /* Data byte has been received; NOT ACK has been returned */
298                         if (numbytes == msg->len - 1) {
299                                 pca_rx_byte(adap, &msg->buf[numbytes], 0);
300                                 curmsg++; numbytes = 0;
301                                 if (curmsg == num)
302                                         pca_stop(adap);
303                                 else
304                                         completed = pca_repeated_start(adap);
305                         } else {
306                                 DEB2("NOT ACK sent after data byte received. "
307                                      "Not final byte. numbytes %d. len %d\n",
308                                      numbytes, msg->len);
309                                 pca_stop(adap);
310                                 goto out;
311                         }
312                         break;
313                 case 0x70: /* Bus error - SDA stuck low */
314                         DEB2("BUS ERROR - SDA Stuck low\n");
315                         pca_reset(adap);
316                         goto out;
317                 case 0x90: /* Bus error - SCL stuck low */
318                         DEB2("BUS ERROR - SCL Stuck low\n");
319                         pca_reset(adap);
320                         goto out;
321                 case 0x00: /* Bus error during master or slave mode due to illegal START or STOP condition */
322                         DEB2("BUS ERROR - Illegal START or STOP\n");
323                         pca_reset(adap);
324                         goto out;
325                 default:
326                         dev_err(&i2c_adap->dev, "unhandled SIO state 0x%02x\n", state);
327                         break;
328                 }
329
330                 if (!completed)
331                         goto out;
332         }
333
334         ret = curmsg;
335  out:
336         DEB1("}}} transferred %d/%d messages. "
337              "status is %#04x. control is %#04x\n",
338              curmsg, num, pca_status(adap),
339              pca_get_con(adap));
340         return ret;
341 }
342
343 static u32 pca_func(struct i2c_adapter *adap)
344 {
345         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
346 }
347
348 static const struct i2c_algorithm pca_algo = {
349         .master_xfer    = pca_xfer,
350         .functionality  = pca_func,
351 };
352
353 static unsigned int pca_probe_chip(struct i2c_adapter *adap)
354 {
355         struct i2c_algo_pca_data *pca_data = adap->algo_data;
356         /* The trick here is to check if there is an indirect register
357          * available. If there is one, we will read the value we first
358          * wrote on I2C_PCA_IADR. Otherwise, we will read the last value
359          * we wrote on I2C_PCA_ADR
360          */
361         pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_IADR);
362         pca_outw(pca_data, I2C_PCA_IND, 0xAA);
363         pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_ITO);
364         pca_outw(pca_data, I2C_PCA_IND, 0x00);
365         pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_IADR);
366         if (pca_inw(pca_data, I2C_PCA_IND) == 0xAA) {
367                 printk(KERN_INFO "%s: PCA9665 detected.\n", adap->name);
368                 pca_data->chip = I2C_PCA_CHIP_9665;
369         } else {
370                 printk(KERN_INFO "%s: PCA9564 detected.\n", adap->name);
371                 pca_data->chip = I2C_PCA_CHIP_9564;
372         }
373         return pca_data->chip;
374 }
375
376 static int pca_init(struct i2c_adapter *adap)
377 {
378         struct i2c_algo_pca_data *pca_data = adap->algo_data;
379
380         adap->algo = &pca_algo;
381
382         if (pca_probe_chip(adap) == I2C_PCA_CHIP_9564) {
383                 static int freqs[] = {330, 288, 217, 146, 88, 59, 44, 36};
384                 int clock;
385
386                 if (pca_data->i2c_clock > 7) {
387                         switch (pca_data->i2c_clock) {
388                         case 330000:
389                                 pca_data->i2c_clock = I2C_PCA_CON_330kHz;
390                                 break;
391                         case 288000:
392                                 pca_data->i2c_clock = I2C_PCA_CON_288kHz;
393                                 break;
394                         case 217000:
395                                 pca_data->i2c_clock = I2C_PCA_CON_217kHz;
396                                 break;
397                         case 146000:
398                                 pca_data->i2c_clock = I2C_PCA_CON_146kHz;
399                                 break;
400                         case 88000:
401                                 pca_data->i2c_clock = I2C_PCA_CON_88kHz;
402                                 break;
403                         case 59000:
404                                 pca_data->i2c_clock = I2C_PCA_CON_59kHz;
405                                 break;
406                         case 44000:
407                                 pca_data->i2c_clock = I2C_PCA_CON_44kHz;
408                                 break;
409                         case 36000:
410                                 pca_data->i2c_clock = I2C_PCA_CON_36kHz;
411                                 break;
412                         default:
413                                 printk(KERN_WARNING
414                                         "%s: Invalid I2C clock speed selected."
415                                         " Using default 59kHz.\n", adap->name);
416                         pca_data->i2c_clock = I2C_PCA_CON_59kHz;
417                         }
418                 } else {
419                         printk(KERN_WARNING "%s: "
420                                 "Choosing the clock frequency based on "
421                                 "index is deprecated."
422                                 " Use the nominal frequency.\n", adap->name);
423                 }
424
425                 pca_reset(pca_data);
426
427                 clock = pca_clock(pca_data);
428                 printk(KERN_INFO "%s: Clock frequency is %dkHz\n",
429                      adap->name, freqs[clock]);
430
431                 pca_set_con(pca_data, I2C_PCA_CON_ENSIO | clock);
432         } else {
433                 int clock;
434                 int mode;
435                 int tlow, thi;
436                 /* Values can be found on PCA9665 datasheet section 7.3.2.6 */
437                 int min_tlow, min_thi;
438                 /* These values are the maximum raise and fall values allowed
439                  * by the I2C operation mode (Standard, Fast or Fast+)
440                  * They are used (added) below to calculate the clock dividers
441                  * of PCA9665. Note that they are slightly different of the
442                  * real maximum, to allow the change on mode exactly on the
443                  * maximum clock rate for each mode
444                  */
445                 int raise_fall_time;
446
447                 if (pca_data->i2c_clock > 1265800) {
448                         printk(KERN_WARNING "%s: I2C clock speed too high."
449                                 " Using 1265.8kHz.\n", adap->name);
450                         pca_data->i2c_clock = 1265800;
451                 }
452
453                 if (pca_data->i2c_clock < 60300) {
454                         printk(KERN_WARNING "%s: I2C clock speed too low."
455                                 " Using 60.3kHz.\n", adap->name);
456                         pca_data->i2c_clock = 60300;
457                 }
458
459                 /* To avoid integer overflow, use clock/100 for calculations */
460                 clock = pca_clock(pca_data) / 100;
461
462                 if (pca_data->i2c_clock > 1000000) {
463                         mode = I2C_PCA_MODE_TURBO;
464                         min_tlow = 14;
465                         min_thi  = 5;
466                         raise_fall_time = 22; /* Raise 11e-8s, Fall 11e-8s */
467                 } else if (pca_data->i2c_clock > 400000) {
468                         mode = I2C_PCA_MODE_FASTP;
469                         min_tlow = 17;
470                         min_thi  = 9;
471                         raise_fall_time = 22; /* Raise 11e-8s, Fall 11e-8s */
472                 } else if (pca_data->i2c_clock > 100000) {
473                         mode = I2C_PCA_MODE_FAST;
474                         min_tlow = 44;
475                         min_thi  = 20;
476                         raise_fall_time = 58; /* Raise 29e-8s, Fall 29e-8s */
477                 } else {
478                         mode = I2C_PCA_MODE_STD;
479                         min_tlow = 157;
480                         min_thi  = 134;
481                         raise_fall_time = 127; /* Raise 29e-8s, Fall 98e-8s */
482                 }
483
484                 /* The minimum clock that respects the thi/tlow = 134/157 is
485                  * 64800 Hz. Below that, we have to fix the tlow to 255 and
486                  * calculate the thi factor.
487                  */
488                 if (clock < 648) {
489                         tlow = 255;
490                         thi = 1000000 - clock * raise_fall_time;
491                         thi /= (I2C_PCA_OSC_PER * clock) - tlow;
492                 } else {
493                         tlow = (1000000 - clock * raise_fall_time) * min_tlow;
494                         tlow /= I2C_PCA_OSC_PER * clock * (min_thi + min_tlow);
495                         thi = tlow * min_thi / min_tlow;
496                 }
497
498                 pca_reset(pca_data);
499
500                 printk(KERN_INFO
501                      "%s: Clock frequency is %dHz\n", adap->name, clock * 100);
502
503                 pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_IMODE);
504                 pca_outw(pca_data, I2C_PCA_IND, mode);
505                 pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_ISCLL);
506                 pca_outw(pca_data, I2C_PCA_IND, tlow);
507                 pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_ISCLH);
508                 pca_outw(pca_data, I2C_PCA_IND, thi);
509
510                 pca_set_con(pca_data, I2C_PCA_CON_ENSIO);
511         }
512         udelay(500); /* 500 us for oscillator to stabilise */
513
514         return 0;
515 }
516
517 /*
518  * registering functions to load algorithms at runtime
519  */
520 int i2c_pca_add_bus(struct i2c_adapter *adap)
521 {
522         int rval;
523
524         rval = pca_init(adap);
525         if (rval)
526                 return rval;
527
528         return i2c_add_adapter(adap);
529 }
530 EXPORT_SYMBOL(i2c_pca_add_bus);
531
532 int i2c_pca_add_numbered_bus(struct i2c_adapter *adap)
533 {
534         int rval;
535
536         rval = pca_init(adap);
537         if (rval)
538                 return rval;
539
540         return i2c_add_numbered_adapter(adap);
541 }
542 EXPORT_SYMBOL(i2c_pca_add_numbered_bus);
543
544 MODULE_AUTHOR("Ian Campbell <icampbell@arcom.com>, "
545         "Wolfram Sang <w.sang@pengutronix.de>");
546 MODULE_DESCRIPTION("I2C-Bus PCA9564/PCA9665 algorithm");
547 MODULE_LICENSE("GPL");
548
549 module_param(i2c_debug, int, 0);