rtc: rtc-s35390a.c needs the bitreverse library
[linux-2.6.git] / drivers / rtc / rtc-x1205.c
1 /*
2  * An i2c driver for the Xicor/Intersil X1205 RTC
3  * Copyright 2004 Karen Spearel
4  * Copyright 2005 Alessandro Zummo
5  *
6  * please send all reports to:
7  *      Karen Spearel <kas111 at gmail dot com>
8  *      Alessandro Zummo <a.zummo@towertech.it>
9  *
10  * based on a lot of other RTC drivers.
11  *
12  * Information and datasheet:
13  * http://www.intersil.com/cda/deviceinfo/0,1477,X1205,00.html
14  *
15  * This program is free software; you can redistribute it and/or modify
16  * it under the terms of the GNU General Public License version 2 as
17  * published by the Free Software Foundation.
18  */
19
20 #include <linux/i2c.h>
21 #include <linux/bcd.h>
22 #include <linux/rtc.h>
23 #include <linux/delay.h>
24
25 #define DRV_VERSION "1.0.7"
26
27 /* Addresses to scan: none. This chip is located at
28  * 0x6f and uses a two bytes register addressing.
29  * Two bytes need to be written to read a single register,
30  * while most other chips just require one and take the second
31  * one as the data to be written. To prevent corrupting
32  * unknown chips, the user must explicitly set the probe parameter.
33  */
34
35 static const unsigned short normal_i2c[] = { I2C_CLIENT_END };
36
37 /* Insmod parameters */
38 I2C_CLIENT_INSMOD;
39
40 /* offsets into CCR area */
41
42 #define CCR_SEC                 0
43 #define CCR_MIN                 1
44 #define CCR_HOUR                2
45 #define CCR_MDAY                3
46 #define CCR_MONTH               4
47 #define CCR_YEAR                5
48 #define CCR_WDAY                6
49 #define CCR_Y2K                 7
50
51 #define X1205_REG_SR            0x3F    /* status register */
52 #define X1205_REG_Y2K           0x37
53 #define X1205_REG_DW            0x36
54 #define X1205_REG_YR            0x35
55 #define X1205_REG_MO            0x34
56 #define X1205_REG_DT            0x33
57 #define X1205_REG_HR            0x32
58 #define X1205_REG_MN            0x31
59 #define X1205_REG_SC            0x30
60 #define X1205_REG_DTR           0x13
61 #define X1205_REG_ATR           0x12
62 #define X1205_REG_INT           0x11
63 #define X1205_REG_0             0x10
64 #define X1205_REG_Y2K1          0x0F
65 #define X1205_REG_DWA1          0x0E
66 #define X1205_REG_YRA1          0x0D
67 #define X1205_REG_MOA1          0x0C
68 #define X1205_REG_DTA1          0x0B
69 #define X1205_REG_HRA1          0x0A
70 #define X1205_REG_MNA1          0x09
71 #define X1205_REG_SCA1          0x08
72 #define X1205_REG_Y2K0          0x07
73 #define X1205_REG_DWA0          0x06
74 #define X1205_REG_YRA0          0x05
75 #define X1205_REG_MOA0          0x04
76 #define X1205_REG_DTA0          0x03
77 #define X1205_REG_HRA0          0x02
78 #define X1205_REG_MNA0          0x01
79 #define X1205_REG_SCA0          0x00
80
81 #define X1205_CCR_BASE          0x30    /* Base address of CCR */
82 #define X1205_ALM0_BASE         0x00    /* Base address of ALARM0 */
83
84 #define X1205_SR_RTCF           0x01    /* Clock failure */
85 #define X1205_SR_WEL            0x02    /* Write Enable Latch */
86 #define X1205_SR_RWEL           0x04    /* Register Write Enable */
87
88 #define X1205_DTR_DTR0          0x01
89 #define X1205_DTR_DTR1          0x02
90 #define X1205_DTR_DTR2          0x04
91
92 #define X1205_HR_MIL            0x80    /* Set in ccr.hour for 24 hr mode */
93
94 /* Prototypes */
95 static int x1205_attach(struct i2c_adapter *adapter);
96 static int x1205_detach(struct i2c_client *client);
97 static int x1205_probe(struct i2c_adapter *adapter, int address, int kind);
98
99 static struct i2c_driver x1205_driver = {
100         .driver         = {
101                 .name   = "x1205",
102         },
103         .id             = I2C_DRIVERID_X1205,
104         .attach_adapter = &x1205_attach,
105         .detach_client  = &x1205_detach,
106 };
107
108 /*
109  * In the routines that deal directly with the x1205 hardware, we use
110  * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch
111  * Epoch is initialized as 2000. Time is set to UTC.
112  */
113 static int x1205_get_datetime(struct i2c_client *client, struct rtc_time *tm,
114                                 unsigned char reg_base)
115 {
116         unsigned char dt_addr[2] = { 0, reg_base };
117
118         unsigned char buf[8];
119
120         struct i2c_msg msgs[] = {
121                 { client->addr, 0, 2, dt_addr },        /* setup read ptr */
122                 { client->addr, I2C_M_RD, 8, buf },     /* read date */
123         };
124
125         /* read date registers */
126         if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
127                 dev_err(&client->dev, "%s: read error\n", __FUNCTION__);
128                 return -EIO;
129         }
130
131         dev_dbg(&client->dev,
132                 "%s: raw read data - sec=%02x, min=%02x, hr=%02x, "
133                 "mday=%02x, mon=%02x, year=%02x, wday=%02x, y2k=%02x\n",
134                 __FUNCTION__,
135                 buf[0], buf[1], buf[2], buf[3],
136                 buf[4], buf[5], buf[6], buf[7]);
137
138         tm->tm_sec = BCD2BIN(buf[CCR_SEC]);
139         tm->tm_min = BCD2BIN(buf[CCR_MIN]);
140         tm->tm_hour = BCD2BIN(buf[CCR_HOUR] & 0x3F); /* hr is 0-23 */
141         tm->tm_mday = BCD2BIN(buf[CCR_MDAY]);
142         tm->tm_mon = BCD2BIN(buf[CCR_MONTH]) - 1; /* mon is 0-11 */
143         tm->tm_year = BCD2BIN(buf[CCR_YEAR])
144                         + (BCD2BIN(buf[CCR_Y2K]) * 100) - 1900;
145         tm->tm_wday = buf[CCR_WDAY];
146
147         dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
148                 "mday=%d, mon=%d, year=%d, wday=%d\n",
149                 __FUNCTION__,
150                 tm->tm_sec, tm->tm_min, tm->tm_hour,
151                 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
152
153         return 0;
154 }
155
156 static int x1205_get_status(struct i2c_client *client, unsigned char *sr)
157 {
158         static unsigned char sr_addr[2] = { 0, X1205_REG_SR };
159
160         struct i2c_msg msgs[] = {
161                 { client->addr, 0, 2, sr_addr },        /* setup read ptr */
162                 { client->addr, I2C_M_RD, 1, sr },      /* read status */
163         };
164
165         /* read status register */
166         if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
167                 dev_err(&client->dev, "%s: read error\n", __FUNCTION__);
168                 return -EIO;
169         }
170
171         return 0;
172 }
173
174 static int x1205_set_datetime(struct i2c_client *client, struct rtc_time *tm,
175                                 int datetoo, u8 reg_base)
176 {
177         int i, xfer;
178         unsigned char buf[8];
179
180         static const unsigned char wel[3] = { 0, X1205_REG_SR,
181                                                 X1205_SR_WEL };
182
183         static const unsigned char rwel[3] = { 0, X1205_REG_SR,
184                                                 X1205_SR_WEL | X1205_SR_RWEL };
185
186         static const unsigned char diswe[3] = { 0, X1205_REG_SR, 0 };
187
188         dev_dbg(&client->dev,
189                 "%s: secs=%d, mins=%d, hours=%d\n",
190                 __FUNCTION__,
191                 tm->tm_sec, tm->tm_min, tm->tm_hour);
192
193         buf[CCR_SEC] = BIN2BCD(tm->tm_sec);
194         buf[CCR_MIN] = BIN2BCD(tm->tm_min);
195
196         /* set hour and 24hr bit */
197         buf[CCR_HOUR] = BIN2BCD(tm->tm_hour) | X1205_HR_MIL;
198
199         /* should we also set the date? */
200         if (datetoo) {
201                 dev_dbg(&client->dev,
202                         "%s: mday=%d, mon=%d, year=%d, wday=%d\n",
203                         __FUNCTION__,
204                         tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
205
206                 buf[CCR_MDAY] = BIN2BCD(tm->tm_mday);
207
208                 /* month, 1 - 12 */
209                 buf[CCR_MONTH] = BIN2BCD(tm->tm_mon + 1);
210
211                 /* year, since the rtc epoch*/
212                 buf[CCR_YEAR] = BIN2BCD(tm->tm_year % 100);
213                 buf[CCR_WDAY] = tm->tm_wday & 0x07;
214                 buf[CCR_Y2K] = BIN2BCD(tm->tm_year / 100);
215         }
216
217         /* this sequence is required to unlock the chip */
218         if ((xfer = i2c_master_send(client, wel, 3)) != 3) {
219                 dev_err(&client->dev, "%s: wel - %d\n", __FUNCTION__, xfer);
220                 return -EIO;
221         }
222
223         if ((xfer = i2c_master_send(client, rwel, 3)) != 3) {
224                 dev_err(&client->dev, "%s: rwel - %d\n", __FUNCTION__, xfer);
225                 return -EIO;
226         }
227
228         /* write register's data */
229         for (i = 0; i < (datetoo ? 8 : 3); i++) {
230                 unsigned char rdata[3] = { 0, reg_base + i, buf[i] };
231
232                 xfer = i2c_master_send(client, rdata, 3);
233                 if (xfer != 3) {
234                         dev_err(&client->dev,
235                                 "%s: xfer=%d addr=%02x, data=%02x\n",
236                                 __FUNCTION__,
237                                  xfer, rdata[1], rdata[2]);
238                         return -EIO;
239                 }
240         };
241
242         /* disable further writes */
243         if ((xfer = i2c_master_send(client, diswe, 3)) != 3) {
244                 dev_err(&client->dev, "%s: diswe - %d\n", __FUNCTION__, xfer);
245                 return -EIO;
246         }
247
248         return 0;
249 }
250
251 static int x1205_fix_osc(struct i2c_client *client)
252 {
253         int err;
254         struct rtc_time tm;
255
256         tm.tm_hour = tm.tm_min = tm.tm_sec = 0;
257
258         if ((err = x1205_set_datetime(client, &tm, 0, X1205_CCR_BASE)) < 0)
259                 dev_err(&client->dev,
260                         "unable to restart the oscillator\n");
261
262         return err;
263 }
264
265 static int x1205_get_dtrim(struct i2c_client *client, int *trim)
266 {
267         unsigned char dtr;
268         static unsigned char dtr_addr[2] = { 0, X1205_REG_DTR };
269
270         struct i2c_msg msgs[] = {
271                 { client->addr, 0, 2, dtr_addr },       /* setup read ptr */
272                 { client->addr, I2C_M_RD, 1, &dtr },    /* read dtr */
273         };
274
275         /* read dtr register */
276         if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
277                 dev_err(&client->dev, "%s: read error\n", __FUNCTION__);
278                 return -EIO;
279         }
280
281         dev_dbg(&client->dev, "%s: raw dtr=%x\n", __FUNCTION__, dtr);
282
283         *trim = 0;
284
285         if (dtr & X1205_DTR_DTR0)
286                 *trim += 20;
287
288         if (dtr & X1205_DTR_DTR1)
289                 *trim += 10;
290
291         if (dtr & X1205_DTR_DTR2)
292                 *trim = -*trim;
293
294         return 0;
295 }
296
297 static int x1205_get_atrim(struct i2c_client *client, int *trim)
298 {
299         s8 atr;
300         static unsigned char atr_addr[2] = { 0, X1205_REG_ATR };
301
302         struct i2c_msg msgs[] = {
303                 { client->addr, 0, 2, atr_addr },       /* setup read ptr */
304                 { client->addr, I2C_M_RD, 1, &atr },    /* read atr */
305         };
306
307         /* read atr register */
308         if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
309                 dev_err(&client->dev, "%s: read error\n", __FUNCTION__);
310                 return -EIO;
311         }
312
313         dev_dbg(&client->dev, "%s: raw atr=%x\n", __FUNCTION__, atr);
314
315         /* atr is a two's complement value on 6 bits,
316          * perform sign extension. The formula is
317          * Catr = (atr * 0.25pF) + 11.00pF.
318          */
319         if (atr & 0x20)
320                 atr |= 0xC0;
321
322         dev_dbg(&client->dev, "%s: raw atr=%x (%d)\n", __FUNCTION__, atr, atr);
323
324         *trim = (atr * 250) + 11000;
325
326         dev_dbg(&client->dev, "%s: real=%d\n", __FUNCTION__, *trim);
327
328         return 0;
329 }
330
331 struct x1205_limit
332 {
333         unsigned char reg, mask, min, max;
334 };
335
336 static int x1205_validate_client(struct i2c_client *client)
337 {
338         int i, xfer;
339
340         /* Probe array. We will read the register at the specified
341          * address and check if the given bits are zero.
342          */
343         static const unsigned char probe_zero_pattern[] = {
344                 /* register, mask */
345                 X1205_REG_SR,   0x18,
346                 X1205_REG_DTR,  0xF8,
347                 X1205_REG_ATR,  0xC0,
348                 X1205_REG_INT,  0x18,
349                 X1205_REG_0,    0xFF,
350         };
351
352         static const struct x1205_limit probe_limits_pattern[] = {
353                 /* register, mask, min, max */
354                 { X1205_REG_Y2K,        0xFF,   19,     20      },
355                 { X1205_REG_DW,         0xFF,   0,      6       },
356                 { X1205_REG_YR,         0xFF,   0,      99      },
357                 { X1205_REG_MO,         0xFF,   0,      12      },
358                 { X1205_REG_DT,         0xFF,   0,      31      },
359                 { X1205_REG_HR,         0x7F,   0,      23      },
360                 { X1205_REG_MN,         0xFF,   0,      59      },
361                 { X1205_REG_SC,         0xFF,   0,      59      },
362                 { X1205_REG_Y2K1,       0xFF,   19,     20      },
363                 { X1205_REG_Y2K0,       0xFF,   19,     20      },
364         };
365
366         /* check that registers have bits a 0 where expected */
367         for (i = 0; i < ARRAY_SIZE(probe_zero_pattern); i += 2) {
368                 unsigned char buf;
369
370                 unsigned char addr[2] = { 0, probe_zero_pattern[i] };
371
372                 struct i2c_msg msgs[2] = {
373                         { client->addr, 0, 2, addr },
374                         { client->addr, I2C_M_RD, 1, &buf },
375                 };
376
377                 if ((xfer = i2c_transfer(client->adapter, msgs, 2)) != 2) {
378                         dev_err(&client->dev,
379                                 "%s: could not read register %x\n",
380                                 __FUNCTION__, probe_zero_pattern[i]);
381
382                         return -EIO;
383                 }
384
385                 if ((buf & probe_zero_pattern[i+1]) != 0) {
386                         dev_err(&client->dev,
387                                 "%s: register=%02x, zero pattern=%d, value=%x\n",
388                                 __FUNCTION__, probe_zero_pattern[i], i, buf);
389
390                         return -ENODEV;
391                 }
392         }
393
394         /* check limits (only registers with bcd values) */
395         for (i = 0; i < ARRAY_SIZE(probe_limits_pattern); i++) {
396                 unsigned char reg, value;
397
398                 unsigned char addr[2] = { 0, probe_limits_pattern[i].reg };
399
400                 struct i2c_msg msgs[2] = {
401                         { client->addr, 0, 2, addr },
402                         { client->addr, I2C_M_RD, 1, &reg },
403                 };
404
405                 if ((xfer = i2c_transfer(client->adapter, msgs, 2)) != 2) {
406                         dev_err(&client->dev,
407                                 "%s: could not read register %x\n",
408                                 __FUNCTION__, probe_limits_pattern[i].reg);
409
410                         return -EIO;
411                 }
412
413                 value = BCD2BIN(reg & probe_limits_pattern[i].mask);
414
415                 if (value > probe_limits_pattern[i].max ||
416                         value < probe_limits_pattern[i].min) {
417                         dev_dbg(&client->dev,
418                                 "%s: register=%x, lim pattern=%d, value=%d\n",
419                                 __FUNCTION__, probe_limits_pattern[i].reg,
420                                 i, value);
421
422                         return -ENODEV;
423                 }
424         }
425
426         return 0;
427 }
428
429 static int x1205_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
430 {
431         return x1205_get_datetime(to_i2c_client(dev),
432                 &alrm->time, X1205_ALM0_BASE);
433 }
434
435 static int x1205_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
436 {
437         return x1205_set_datetime(to_i2c_client(dev),
438                 &alrm->time, 1, X1205_ALM0_BASE);
439 }
440
441 static int x1205_rtc_read_time(struct device *dev, struct rtc_time *tm)
442 {
443         return x1205_get_datetime(to_i2c_client(dev),
444                 tm, X1205_CCR_BASE);
445 }
446
447 static int x1205_rtc_set_time(struct device *dev, struct rtc_time *tm)
448 {
449         return x1205_set_datetime(to_i2c_client(dev),
450                 tm, 1, X1205_CCR_BASE);
451 }
452
453 static int x1205_rtc_proc(struct device *dev, struct seq_file *seq)
454 {
455         int err, dtrim, atrim;
456
457         if ((err = x1205_get_dtrim(to_i2c_client(dev), &dtrim)) == 0)
458                 seq_printf(seq, "digital_trim\t: %d ppm\n", dtrim);
459
460         if ((err = x1205_get_atrim(to_i2c_client(dev), &atrim)) == 0)
461                 seq_printf(seq, "analog_trim\t: %d.%02d pF\n",
462                         atrim / 1000, atrim % 1000);
463         return 0;
464 }
465
466 static const struct rtc_class_ops x1205_rtc_ops = {
467         .proc           = x1205_rtc_proc,
468         .read_time      = x1205_rtc_read_time,
469         .set_time       = x1205_rtc_set_time,
470         .read_alarm     = x1205_rtc_read_alarm,
471         .set_alarm      = x1205_rtc_set_alarm,
472 };
473
474 static ssize_t x1205_sysfs_show_atrim(struct device *dev,
475                                 struct device_attribute *attr, char *buf)
476 {
477         int err, atrim;
478
479         err = x1205_get_atrim(to_i2c_client(dev), &atrim);
480         if (err)
481                 return err;
482
483         return sprintf(buf, "%d.%02d pF\n", atrim / 1000, atrim % 1000);
484 }
485 static DEVICE_ATTR(atrim, S_IRUGO, x1205_sysfs_show_atrim, NULL);
486
487 static ssize_t x1205_sysfs_show_dtrim(struct device *dev,
488                                 struct device_attribute *attr, char *buf)
489 {
490         int err, dtrim;
491
492         err = x1205_get_dtrim(to_i2c_client(dev), &dtrim);
493         if (err)
494                 return err;
495
496         return sprintf(buf, "%d ppm\n", dtrim);
497 }
498 static DEVICE_ATTR(dtrim, S_IRUGO, x1205_sysfs_show_dtrim, NULL);
499
500 static int x1205_attach(struct i2c_adapter *adapter)
501 {
502         return i2c_probe(adapter, &addr_data, x1205_probe);
503 }
504
505 static int x1205_probe(struct i2c_adapter *adapter, int address, int kind)
506 {
507         int err = 0;
508         unsigned char sr;
509         struct i2c_client *client;
510         struct rtc_device *rtc;
511
512         dev_dbg(&adapter->dev, "%s\n", __FUNCTION__);
513
514         if (!i2c_check_functionality(adapter, I2C_FUNC_I2C)) {
515                 err = -ENODEV;
516                 goto exit;
517         }
518
519         if (!(client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL))) {
520                 err = -ENOMEM;
521                 goto exit;
522         }
523
524         /* I2C client */
525         client->addr = address;
526         client->driver = &x1205_driver;
527         client->adapter = adapter;
528
529         strlcpy(client->name, x1205_driver.driver.name, I2C_NAME_SIZE);
530
531         /* Verify the chip is really an X1205 */
532         if (kind < 0) {
533                 if (x1205_validate_client(client) < 0) {
534                         err = -ENODEV;
535                         goto exit_kfree;
536                 }
537         }
538
539         /* Inform the i2c layer */
540         if ((err = i2c_attach_client(client)))
541                 goto exit_kfree;
542
543         dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");
544
545         rtc = rtc_device_register(x1205_driver.driver.name, &client->dev,
546                                 &x1205_rtc_ops, THIS_MODULE);
547
548         if (IS_ERR(rtc)) {
549                 err = PTR_ERR(rtc);
550                 goto exit_detach;
551         }
552
553         i2c_set_clientdata(client, rtc);
554
555         /* Check for power failures and eventualy enable the osc */
556         if ((err = x1205_get_status(client, &sr)) == 0) {
557                 if (sr & X1205_SR_RTCF) {
558                         dev_err(&client->dev,
559                                 "power failure detected, "
560                                 "please set the clock\n");
561                         udelay(50);
562                         x1205_fix_osc(client);
563                 }
564         }
565         else
566                 dev_err(&client->dev, "couldn't read status\n");
567
568         err = device_create_file(&client->dev, &dev_attr_atrim);
569         if (err) goto exit_devreg;
570         err = device_create_file(&client->dev, &dev_attr_dtrim);
571         if (err) goto exit_atrim;
572
573         return 0;
574
575 exit_atrim:
576         device_remove_file(&client->dev, &dev_attr_atrim);
577
578 exit_devreg:
579         rtc_device_unregister(rtc);
580
581 exit_detach:
582         i2c_detach_client(client);
583
584 exit_kfree:
585         kfree(client);
586
587 exit:
588         return err;
589 }
590
591 static int x1205_detach(struct i2c_client *client)
592 {
593         int err;
594         struct rtc_device *rtc = i2c_get_clientdata(client);
595
596         if (rtc)
597                 rtc_device_unregister(rtc);
598
599         if ((err = i2c_detach_client(client)))
600                 return err;
601
602         kfree(client);
603
604         return 0;
605 }
606
607 static int __init x1205_init(void)
608 {
609         return i2c_add_driver(&x1205_driver);
610 }
611
612 static void __exit x1205_exit(void)
613 {
614         i2c_del_driver(&x1205_driver);
615 }
616
617 MODULE_AUTHOR(
618         "Karen Spearel <kas111 at gmail dot com>, "
619         "Alessandro Zummo <a.zummo@towertech.it>");
620 MODULE_DESCRIPTION("Xicor/Intersil X1205 RTC driver");
621 MODULE_LICENSE("GPL");
622 MODULE_VERSION(DRV_VERSION);
623
624 module_init(x1205_init);
625 module_exit(x1205_exit);