Merge tag 'for-linus-20180803' of git://git.kernel.dk/linux-block
[sfrench/cifs-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
17 #include <linux/kernel.h>
18 #include <linux/module.h>
19 #include <linux/moduleparam.h>
20 #include <linux/delay.h>
21 #include <linux/jiffies.h>
22 #include <linux/errno.h>
23 #include <linux/i2c.h>
24 #include <linux/i2c-algo-pca.h>
25
26 #define DEB1(fmt, args...) do { if (i2c_debug >= 1)                     \
27                                  printk(KERN_DEBUG fmt, ## args); } while (0)
28 #define DEB2(fmt, args...) do { if (i2c_debug >= 2)                     \
29                                  printk(KERN_DEBUG fmt, ## args); } while (0)
30 #define DEB3(fmt, args...) do { if (i2c_debug >= 3)                     \
31                                  printk(KERN_DEBUG fmt, ## args); } while (0)
32
33 static int i2c_debug;
34
35 #define pca_outw(adap, reg, val) adap->write_byte(adap->data, reg, val)
36 #define pca_inw(adap, reg) adap->read_byte(adap->data, reg)
37
38 #define pca_status(adap) pca_inw(adap, I2C_PCA_STA)
39 #define pca_clock(adap) adap->i2c_clock
40 #define pca_set_con(adap, val) pca_outw(adap, I2C_PCA_CON, val)
41 #define pca_get_con(adap) pca_inw(adap, I2C_PCA_CON)
42 #define pca_wait(adap) adap->wait_for_completion(adap->data)
43
44 static void pca_reset(struct i2c_algo_pca_data *adap)
45 {
46         if (adap->chip == I2C_PCA_CHIP_9665) {
47                 /* Ignore the reset function from the module,
48                  * we can use the parallel bus reset.
49                  */
50                 pca_outw(adap, I2C_PCA_INDPTR, I2C_PCA_IPRESET);
51                 pca_outw(adap, I2C_PCA_IND, 0xA5);
52                 pca_outw(adap, I2C_PCA_IND, 0x5A);
53         } else {
54                 adap->reset_chip(adap->data);
55         }
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 = i2c_8bit_addr_from_msg(msg);
116
117         DEB2("=== SLAVE ADDRESS %#04x+%c=%#04x\n",
118              msg->addr, msg->flags & I2C_M_RD ? 'R' : 'W', addr);
119
120         pca_outw(adap, I2C_PCA_DAT, addr);
121
122         sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_STA|I2C_PCA_CON_SI);
123         pca_set_con(adap, sta);
124
125         return pca_wait(adap);
126 }
127
128 /*
129  * Transmit a byte.
130  *
131  * Returns after the byte has been transmitted
132  */
133 static int pca_tx_byte(struct i2c_algo_pca_data *adap,
134                        __u8 b)
135 {
136         int sta = pca_get_con(adap);
137         DEB2("=== WRITE %#04x\n", b);
138         pca_outw(adap, I2C_PCA_DAT, b);
139
140         sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_STA|I2C_PCA_CON_SI);
141         pca_set_con(adap, sta);
142
143         return pca_wait(adap);
144 }
145
146 /*
147  * Receive a byte
148  *
149  * returns immediately.
150  */
151 static void pca_rx_byte(struct i2c_algo_pca_data *adap,
152                         __u8 *b, int ack)
153 {
154         *b = pca_inw(adap, I2C_PCA_DAT);
155         DEB2("=== READ %#04x %s\n", *b, ack ? "ACK" : "NACK");
156 }
157
158 /*
159  * Setup ACK or NACK for next received byte and wait for it to arrive.
160  *
161  * Returns after next byte has arrived.
162  */
163 static int pca_rx_ack(struct i2c_algo_pca_data *adap,
164                       int ack)
165 {
166         int sta = pca_get_con(adap);
167
168         sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_STA|I2C_PCA_CON_SI|I2C_PCA_CON_AA);
169
170         if (ack)
171                 sta |= I2C_PCA_CON_AA;
172
173         pca_set_con(adap, sta);
174         return pca_wait(adap);
175 }
176
177 static int pca_xfer(struct i2c_adapter *i2c_adap,
178                     struct i2c_msg *msgs,
179                     int num)
180 {
181         struct i2c_algo_pca_data *adap = i2c_adap->algo_data;
182         struct i2c_msg *msg = NULL;
183         int curmsg;
184         int numbytes = 0;
185         int state;
186         int ret;
187         int completed = 1;
188         unsigned long timeout = jiffies + i2c_adap->timeout;
189
190         while ((state = pca_status(adap)) != 0xf8) {
191                 if (time_before(jiffies, timeout)) {
192                         msleep(10);
193                 } else {
194                         dev_dbg(&i2c_adap->dev, "bus is not idle. status is "
195                                 "%#04x\n", state);
196                         return -EBUSY;
197                 }
198         }
199
200         DEB1("{{{ XFER %d messages\n", num);
201
202         if (i2c_debug >= 2) {
203                 for (curmsg = 0; curmsg < num; curmsg++) {
204                         int addr, i;
205                         msg = &msgs[curmsg];
206
207                         addr = (0x7f & msg->addr) ;
208
209                         if (msg->flags & I2C_M_RD)
210                                 printk(KERN_INFO "    [%02d] RD %d bytes from %#02x [%#02x, ...]\n",
211                                        curmsg, msg->len, addr, (addr << 1) | 1);
212                         else {
213                                 printk(KERN_INFO "    [%02d] WR %d bytes to %#02x [%#02x%s",
214                                        curmsg, msg->len, addr, addr << 1,
215                                        msg->len == 0 ? "" : ", ");
216                                 for (i = 0; i < msg->len; i++)
217                                         printk("%#04x%s", msg->buf[i], i == msg->len - 1 ? "" : ", ");
218                                 printk("]\n");
219                         }
220                 }
221         }
222
223         curmsg = 0;
224         ret = -EIO;
225         while (curmsg < num) {
226                 state = pca_status(adap);
227
228                 DEB3("STATE is 0x%02x\n", state);
229                 msg = &msgs[curmsg];
230
231                 switch (state) {
232                 case 0xf8: /* On reset or stop the bus is idle */
233                         completed = pca_start(adap);
234                         break;
235
236                 case 0x08: /* A START condition has been transmitted */
237                 case 0x10: /* A repeated start condition has been transmitted */
238                         completed = pca_address(adap, msg);
239                         break;
240
241                 case 0x18: /* SLA+W has been transmitted; ACK has been received */
242                 case 0x28: /* Data byte in I2CDAT has been transmitted; ACK has been received */
243                         if (numbytes < msg->len) {
244                                 completed = pca_tx_byte(adap,
245                                                         msg->buf[numbytes]);
246                                 numbytes++;
247                                 break;
248                         }
249                         curmsg++; numbytes = 0;
250                         if (curmsg == num)
251                                 pca_stop(adap);
252                         else
253                                 completed = pca_repeated_start(adap);
254                         break;
255
256                 case 0x20: /* SLA+W has been transmitted; NOT ACK has been received */
257                         DEB2("NOT ACK received after SLA+W\n");
258                         pca_stop(adap);
259                         ret = -ENXIO;
260                         goto out;
261
262                 case 0x40: /* SLA+R has been transmitted; ACK has been received */
263                         completed = pca_rx_ack(adap, msg->len > 1);
264                         break;
265
266                 case 0x50: /* Data bytes has been received; ACK has been returned */
267                         if (numbytes < msg->len) {
268                                 pca_rx_byte(adap, &msg->buf[numbytes], 1);
269                                 numbytes++;
270                                 completed = pca_rx_ack(adap,
271                                                        numbytes < msg->len - 1);
272                                 break;
273                         }
274                         curmsg++; numbytes = 0;
275                         if (curmsg == num)
276                                 pca_stop(adap);
277                         else
278                                 completed = pca_repeated_start(adap);
279                         break;
280
281                 case 0x48: /* SLA+R has been transmitted; NOT ACK has been received */
282                         DEB2("NOT ACK received after SLA+R\n");
283                         pca_stop(adap);
284                         ret = -ENXIO;
285                         goto out;
286
287                 case 0x30: /* Data byte in I2CDAT has been transmitted; NOT ACK has been received */
288                         DEB2("NOT ACK received after data byte\n");
289                         pca_stop(adap);
290                         goto out;
291
292                 case 0x38: /* Arbitration lost during SLA+W, SLA+R or data bytes */
293                         DEB2("Arbitration lost\n");
294                         /*
295                          * The PCA9564 data sheet (2006-09-01) says "A
296                          * START condition will be transmitted when the
297                          * bus becomes free (STOP or SCL and SDA high)"
298                          * when the STA bit is set (p. 11).
299                          *
300                          * In case this won't work, try pca_reset()
301                          * instead.
302                          */
303                         pca_start(adap);
304                         goto out;
305
306                 case 0x58: /* Data byte has been received; NOT ACK has been returned */
307                         if (numbytes == msg->len - 1) {
308                                 pca_rx_byte(adap, &msg->buf[numbytes], 0);
309                                 curmsg++; numbytes = 0;
310                                 if (curmsg == num)
311                                         pca_stop(adap);
312                                 else
313                                         completed = pca_repeated_start(adap);
314                         } else {
315                                 DEB2("NOT ACK sent after data byte received. "
316                                      "Not final byte. numbytes %d. len %d\n",
317                                      numbytes, msg->len);
318                                 pca_stop(adap);
319                                 goto out;
320                         }
321                         break;
322                 case 0x70: /* Bus error - SDA stuck low */
323                         DEB2("BUS ERROR - SDA Stuck low\n");
324                         pca_reset(adap);
325                         goto out;
326                 case 0x90: /* Bus error - SCL stuck low */
327                         DEB2("BUS ERROR - SCL Stuck low\n");
328                         pca_reset(adap);
329                         goto out;
330                 case 0x00: /* Bus error during master or slave mode due to illegal START or STOP condition */
331                         DEB2("BUS ERROR - Illegal START or STOP\n");
332                         pca_reset(adap);
333                         goto out;
334                 default:
335                         dev_err(&i2c_adap->dev, "unhandled SIO state 0x%02x\n", state);
336                         break;
337                 }
338
339                 if (!completed)
340                         goto out;
341         }
342
343         ret = curmsg;
344  out:
345         DEB1("}}} transferred %d/%d messages. "
346              "status is %#04x. control is %#04x\n",
347              curmsg, num, pca_status(adap),
348              pca_get_con(adap));
349         return ret;
350 }
351
352 static u32 pca_func(struct i2c_adapter *adap)
353 {
354         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
355 }
356
357 static const struct i2c_algorithm pca_algo = {
358         .master_xfer    = pca_xfer,
359         .functionality  = pca_func,
360 };
361
362 static unsigned int pca_probe_chip(struct i2c_adapter *adap)
363 {
364         struct i2c_algo_pca_data *pca_data = adap->algo_data;
365         /* The trick here is to check if there is an indirect register
366          * available. If there is one, we will read the value we first
367          * wrote on I2C_PCA_IADR. Otherwise, we will read the last value
368          * we wrote on I2C_PCA_ADR
369          */
370         pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_IADR);
371         pca_outw(pca_data, I2C_PCA_IND, 0xAA);
372         pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_ITO);
373         pca_outw(pca_data, I2C_PCA_IND, 0x00);
374         pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_IADR);
375         if (pca_inw(pca_data, I2C_PCA_IND) == 0xAA) {
376                 printk(KERN_INFO "%s: PCA9665 detected.\n", adap->name);
377                 pca_data->chip = I2C_PCA_CHIP_9665;
378         } else {
379                 printk(KERN_INFO "%s: PCA9564 detected.\n", adap->name);
380                 pca_data->chip = I2C_PCA_CHIP_9564;
381         }
382         return pca_data->chip;
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                 if (pca_data->i2c_clock > 1265800) {
457                         printk(KERN_WARNING "%s: I2C clock speed too high."
458                                 " Using 1265.8kHz.\n", adap->name);
459                         pca_data->i2c_clock = 1265800;
460                 }
461
462                 if (pca_data->i2c_clock < 60300) {
463                         printk(KERN_WARNING "%s: I2C clock speed too low."
464                                 " Using 60.3kHz.\n", adap->name);
465                         pca_data->i2c_clock = 60300;
466                 }
467
468                 /* To avoid integer overflow, use clock/100 for calculations */
469                 clock = pca_clock(pca_data) / 100;
470
471                 if (pca_data->i2c_clock > 1000000) {
472                         mode = I2C_PCA_MODE_TURBO;
473                         min_tlow = 14;
474                         min_thi  = 5;
475                         raise_fall_time = 22; /* Raise 11e-8s, Fall 11e-8s */
476                 } else if (pca_data->i2c_clock > 400000) {
477                         mode = I2C_PCA_MODE_FASTP;
478                         min_tlow = 17;
479                         min_thi  = 9;
480                         raise_fall_time = 22; /* Raise 11e-8s, Fall 11e-8s */
481                 } else if (pca_data->i2c_clock > 100000) {
482                         mode = I2C_PCA_MODE_FAST;
483                         min_tlow = 44;
484                         min_thi  = 20;
485                         raise_fall_time = 58; /* Raise 29e-8s, Fall 29e-8s */
486                 } else {
487                         mode = I2C_PCA_MODE_STD;
488                         min_tlow = 157;
489                         min_thi  = 134;
490                         raise_fall_time = 127; /* Raise 29e-8s, Fall 98e-8s */
491                 }
492
493                 /* The minimum clock that respects the thi/tlow = 134/157 is
494                  * 64800 Hz. Below that, we have to fix the tlow to 255 and
495                  * calculate the thi factor.
496                  */
497                 if (clock < 648) {
498                         tlow = 255;
499                         thi = 1000000 - clock * raise_fall_time;
500                         thi /= (I2C_PCA_OSC_PER * clock) - tlow;
501                 } else {
502                         tlow = (1000000 - clock * raise_fall_time) * min_tlow;
503                         tlow /= I2C_PCA_OSC_PER * clock * (min_thi + min_tlow);
504                         thi = tlow * min_thi / min_tlow;
505                 }
506
507                 pca_reset(pca_data);
508
509                 printk(KERN_INFO
510                      "%s: Clock frequency is %dHz\n", adap->name, clock * 100);
511
512                 pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_IMODE);
513                 pca_outw(pca_data, I2C_PCA_IND, mode);
514                 pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_ISCLL);
515                 pca_outw(pca_data, I2C_PCA_IND, tlow);
516                 pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_ISCLH);
517                 pca_outw(pca_data, I2C_PCA_IND, thi);
518
519                 pca_set_con(pca_data, I2C_PCA_CON_ENSIO);
520         }
521         udelay(500); /* 500 us for oscillator to stabilise */
522
523         return 0;
524 }
525
526 /*
527  * registering functions to load algorithms at runtime
528  */
529 int i2c_pca_add_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_adapter(adap);
538 }
539 EXPORT_SYMBOL(i2c_pca_add_bus);
540
541 int i2c_pca_add_numbered_bus(struct i2c_adapter *adap)
542 {
543         int rval;
544
545         rval = pca_init(adap);
546         if (rval)
547                 return rval;
548
549         return i2c_add_numbered_adapter(adap);
550 }
551 EXPORT_SYMBOL(i2c_pca_add_numbered_bus);
552
553 MODULE_AUTHOR("Ian Campbell <icampbell@arcom.com>, "
554         "Wolfram Sang <w.sang@pengutronix.de>");
555 MODULE_DESCRIPTION("I2C-Bus PCA9564/PCA9665 algorithm");
556 MODULE_LICENSE("GPL");
557
558 module_param(i2c_debug, int, 0);