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