Merge tag 'perf-urgent-for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git...
[platform/adaptation/renesas_rcar/renesas_kernel.git] / drivers / i2c / algos / i2c-algo-pca.c
1 /*
2  *  i2c-algo-pca.c i2c driver algorithms for PCA9564 adapters
3  *    Copyright (C) 2004 Arcom Control Systems
4  *    Copyright (C) 2008 Pengutronix
5  *
6  *  This program is free software; you can redistribute it and/or modify
7  *  it under the terms of the GNU General Public License as published by
8  *  the Free Software Foundation; either version 2 of the License, or
9  *  (at your option) any later version.
10  *
11  *  This program is distributed in the hope that it will be useful,
12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  *  GNU General Public License for more details.
15  *
16  *  You should have received a copy of the GNU General Public License
17  *  along with this program; if not, write to the Free Software
18  *  Foundation, Inc., 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
38 static int i2c_debug;
39
40 #define pca_outw(adap, reg, val) adap->write_byte(adap->data, reg, val)
41 #define pca_inw(adap, reg) adap->read_byte(adap->data, reg)
42
43 #define pca_status(adap) pca_inw(adap, I2C_PCA_STA)
44 #define pca_clock(adap) adap->i2c_clock
45 #define pca_set_con(adap, val) pca_outw(adap, I2C_PCA_CON, val)
46 #define pca_get_con(adap) pca_inw(adap, I2C_PCA_CON)
47 #define pca_wait(adap) adap->wait_for_completion(adap->data)
48
49 static 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  */
68 static 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  */
83 static 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  */
102 static 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  */
116 static 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  */
141 static 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  */
159 static 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  */
171 static 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
185 static 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
360 static u32 pca_func(struct i2c_adapter *adap)
361 {
362         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
363 }
364
365 static const struct i2c_algorithm pca_algo = {
366         .master_xfer    = pca_xfer,
367         .functionality  = pca_func,
368 };
369
370 static 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
393 static 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  */
537 int 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 }
547 EXPORT_SYMBOL(i2c_pca_add_bus);
548
549 int 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 }
559 EXPORT_SYMBOL(i2c_pca_add_numbered_bus);
560
561 MODULE_AUTHOR("Ian Campbell <icampbell@arcom.com>, "
562         "Wolfram Sang <w.sang@pengutronix.de>");
563 MODULE_DESCRIPTION("I2C-Bus PCA9564/PCA9665 algorithm");
564 MODULE_LICENSE("GPL");
565
566 module_param(i2c_debug, int, 0);