Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-2.6
[linux-2.6.git] / drivers / rtc / rtc-isl1208.c
1 /*
2  * Intersil ISL1208 rtc class driver
3  *
4  * Copyright 2005,2006 Hebert Valerio Riedel <hvr@gnu.org>
5  *
6  *  This program is free software; you can redistribute  it and/or modify it
7  *  under  the terms of  the GNU General  Public License as published by the
8  *  Free Software Foundation;  either version 2 of the  License, or (at your
9  *  option) any later version.
10  *
11  */
12
13 #include <linux/module.h>
14 #include <linux/i2c.h>
15 #include <linux/bcd.h>
16 #include <linux/rtc.h>
17
18 #define DRV_VERSION "0.3"
19
20 /* Register map */
21 /* rtc section */
22 #define ISL1208_REG_SC  0x00
23 #define ISL1208_REG_MN  0x01
24 #define ISL1208_REG_HR  0x02
25 #define ISL1208_REG_HR_MIL     (1<<7)   /* 24h/12h mode */
26 #define ISL1208_REG_HR_PM      (1<<5)   /* PM/AM bit in 12h mode */
27 #define ISL1208_REG_DT  0x03
28 #define ISL1208_REG_MO  0x04
29 #define ISL1208_REG_YR  0x05
30 #define ISL1208_REG_DW  0x06
31 #define ISL1208_RTC_SECTION_LEN 7
32
33 /* control/status section */
34 #define ISL1208_REG_SR  0x07
35 #define ISL1208_REG_SR_ARST    (1<<7)   /* auto reset */
36 #define ISL1208_REG_SR_XTOSCB  (1<<6)   /* crystal oscillator */
37 #define ISL1208_REG_SR_WRTC    (1<<4)   /* write rtc */
38 #define ISL1208_REG_SR_ALM     (1<<2)   /* alarm */
39 #define ISL1208_REG_SR_BAT     (1<<1)   /* battery */
40 #define ISL1208_REG_SR_RTCF    (1<<0)   /* rtc fail */
41 #define ISL1208_REG_INT 0x08
42 #define ISL1208_REG_09  0x09    /* reserved */
43 #define ISL1208_REG_ATR 0x0a
44 #define ISL1208_REG_DTR 0x0b
45
46 /* alarm section */
47 #define ISL1208_REG_SCA 0x0c
48 #define ISL1208_REG_MNA 0x0d
49 #define ISL1208_REG_HRA 0x0e
50 #define ISL1208_REG_DTA 0x0f
51 #define ISL1208_REG_MOA 0x10
52 #define ISL1208_REG_DWA 0x11
53 #define ISL1208_ALARM_SECTION_LEN 6
54
55 /* user section */
56 #define ISL1208_REG_USR1 0x12
57 #define ISL1208_REG_USR2 0x13
58 #define ISL1208_USR_SECTION_LEN 2
59
60 static struct i2c_driver isl1208_driver;
61
62 /* block read */
63 static int
64 isl1208_i2c_read_regs(struct i2c_client *client, u8 reg, u8 buf[],
65                       unsigned len)
66 {
67         u8 reg_addr[1] = { reg };
68         struct i2c_msg msgs[2] = {
69                 {client->addr, 0, sizeof(reg_addr), reg_addr}
70                 ,
71                 {client->addr, I2C_M_RD, len, buf}
72         };
73         int ret;
74
75         BUG_ON(reg > ISL1208_REG_USR2);
76         BUG_ON(reg + len > ISL1208_REG_USR2 + 1);
77
78         ret = i2c_transfer(client->adapter, msgs, 2);
79         if (ret > 0)
80                 ret = 0;
81         return ret;
82 }
83
84 /* block write */
85 static int
86 isl1208_i2c_set_regs(struct i2c_client *client, u8 reg, u8 const buf[],
87                      unsigned len)
88 {
89         u8 i2c_buf[ISL1208_REG_USR2 + 2];
90         struct i2c_msg msgs[1] = {
91                 {client->addr, 0, len + 1, i2c_buf}
92         };
93         int ret;
94
95         BUG_ON(reg > ISL1208_REG_USR2);
96         BUG_ON(reg + len > ISL1208_REG_USR2 + 1);
97
98         i2c_buf[0] = reg;
99         memcpy(&i2c_buf[1], &buf[0], len);
100
101         ret = i2c_transfer(client->adapter, msgs, 1);
102         if (ret > 0)
103                 ret = 0;
104         return ret;
105 }
106
107 /* simple check to see wether we have a isl1208 */
108 static int
109 isl1208_i2c_validate_client(struct i2c_client *client)
110 {
111         u8 regs[ISL1208_RTC_SECTION_LEN] = { 0, };
112         u8 zero_mask[ISL1208_RTC_SECTION_LEN] = {
113                 0x80, 0x80, 0x40, 0xc0, 0xe0, 0x00, 0xf8
114         };
115         int i;
116         int ret;
117
118         ret = isl1208_i2c_read_regs(client, 0, regs, ISL1208_RTC_SECTION_LEN);
119         if (ret < 0)
120                 return ret;
121
122         for (i = 0; i < ISL1208_RTC_SECTION_LEN; ++i) {
123                 if (regs[i] & zero_mask[i])     /* check if bits are cleared */
124                         return -ENODEV;
125         }
126
127         return 0;
128 }
129
130 static int
131 isl1208_i2c_get_sr(struct i2c_client *client)
132 {
133         int sr = i2c_smbus_read_byte_data(client, ISL1208_REG_SR);
134         if (sr < 0)
135                 return -EIO;
136
137         return sr;
138 }
139
140 static int
141 isl1208_i2c_get_atr(struct i2c_client *client)
142 {
143         int atr = i2c_smbus_read_byte_data(client, ISL1208_REG_ATR);
144         if (atr < 0)
145                 return atr;
146
147         /* The 6bit value in the ATR register controls the load
148          * capacitance C_load * in steps of 0.25pF
149          *
150          * bit (1<<5) of the ATR register is inverted
151          *
152          * C_load(ATR=0x20) =  4.50pF
153          * C_load(ATR=0x00) = 12.50pF
154          * C_load(ATR=0x1f) = 20.25pF
155          *
156          */
157
158         atr &= 0x3f;            /* mask out lsb */
159         atr ^= 1 << 5;          /* invert 6th bit */
160         atr += 2 * 9;           /* add offset of 4.5pF; unit[atr] = 0.25pF */
161
162         return atr;
163 }
164
165 static int
166 isl1208_i2c_get_dtr(struct i2c_client *client)
167 {
168         int dtr = i2c_smbus_read_byte_data(client, ISL1208_REG_DTR);
169         if (dtr < 0)
170                 return -EIO;
171
172         /* dtr encodes adjustments of {-60,-40,-20,0,20,40,60} ppm */
173         dtr = ((dtr & 0x3) * 20) * (dtr & (1 << 2) ? -1 : 1);
174
175         return dtr;
176 }
177
178 static int
179 isl1208_i2c_get_usr(struct i2c_client *client)
180 {
181         u8 buf[ISL1208_USR_SECTION_LEN] = { 0, };
182         int ret;
183
184         ret = isl1208_i2c_read_regs(client, ISL1208_REG_USR1, buf,
185                                     ISL1208_USR_SECTION_LEN);
186         if (ret < 0)
187                 return ret;
188
189         return (buf[1] << 8) | buf[0];
190 }
191
192 static int
193 isl1208_i2c_set_usr(struct i2c_client *client, u16 usr)
194 {
195         u8 buf[ISL1208_USR_SECTION_LEN];
196
197         buf[0] = usr & 0xff;
198         buf[1] = (usr >> 8) & 0xff;
199
200         return isl1208_i2c_set_regs(client, ISL1208_REG_USR1, buf,
201                                     ISL1208_USR_SECTION_LEN);
202 }
203
204 static int
205 isl1208_rtc_proc(struct device *dev, struct seq_file *seq)
206 {
207         struct i2c_client *const client = to_i2c_client(dev);
208         int sr, dtr, atr, usr;
209
210         sr = isl1208_i2c_get_sr(client);
211         if (sr < 0) {
212                 dev_err(&client->dev, "%s: reading SR failed\n", __func__);
213                 return sr;
214         }
215
216         seq_printf(seq, "status_reg\t:%s%s%s%s%s%s (0x%.2x)\n",
217                    (sr & ISL1208_REG_SR_RTCF) ? " RTCF" : "",
218                    (sr & ISL1208_REG_SR_BAT) ? " BAT" : "",
219                    (sr & ISL1208_REG_SR_ALM) ? " ALM" : "",
220                    (sr & ISL1208_REG_SR_WRTC) ? " WRTC" : "",
221                    (sr & ISL1208_REG_SR_XTOSCB) ? " XTOSCB" : "",
222                    (sr & ISL1208_REG_SR_ARST) ? " ARST" : "", sr);
223
224         seq_printf(seq, "batt_status\t: %s\n",
225                    (sr & ISL1208_REG_SR_RTCF) ? "bad" : "okay");
226
227         dtr = isl1208_i2c_get_dtr(client);
228         if (dtr >= 0 - 1)
229                 seq_printf(seq, "digital_trim\t: %d ppm\n", dtr);
230
231         atr = isl1208_i2c_get_atr(client);
232         if (atr >= 0)
233                 seq_printf(seq, "analog_trim\t: %d.%.2d pF\n",
234                            atr >> 2, (atr & 0x3) * 25);
235
236         usr = isl1208_i2c_get_usr(client);
237         if (usr >= 0)
238                 seq_printf(seq, "user_data\t: 0x%.4x\n", usr);
239
240         return 0;
241 }
242
243 static int
244 isl1208_i2c_read_time(struct i2c_client *client, struct rtc_time *tm)
245 {
246         int sr;
247         u8 regs[ISL1208_RTC_SECTION_LEN] = { 0, };
248
249         sr = isl1208_i2c_get_sr(client);
250         if (sr < 0) {
251                 dev_err(&client->dev, "%s: reading SR failed\n", __func__);
252                 return -EIO;
253         }
254
255         sr = isl1208_i2c_read_regs(client, 0, regs, ISL1208_RTC_SECTION_LEN);
256         if (sr < 0) {
257                 dev_err(&client->dev, "%s: reading RTC section failed\n",
258                         __func__);
259                 return sr;
260         }
261
262         tm->tm_sec = bcd2bin(regs[ISL1208_REG_SC]);
263         tm->tm_min = bcd2bin(regs[ISL1208_REG_MN]);
264
265         /* HR field has a more complex interpretation */
266         {
267                 const u8 _hr = regs[ISL1208_REG_HR];
268                 if (_hr & ISL1208_REG_HR_MIL)   /* 24h format */
269                         tm->tm_hour = bcd2bin(_hr & 0x3f);
270                 else {
271                         /* 12h format */
272                         tm->tm_hour = bcd2bin(_hr & 0x1f);
273                         if (_hr & ISL1208_REG_HR_PM)    /* PM flag set */
274                                 tm->tm_hour += 12;
275                 }
276         }
277
278         tm->tm_mday = bcd2bin(regs[ISL1208_REG_DT]);
279         tm->tm_mon = bcd2bin(regs[ISL1208_REG_MO]) - 1; /* rtc starts at 1 */
280         tm->tm_year = bcd2bin(regs[ISL1208_REG_YR]) + 100;
281         tm->tm_wday = bcd2bin(regs[ISL1208_REG_DW]);
282
283         return 0;
284 }
285
286 static int
287 isl1208_i2c_read_alarm(struct i2c_client *client, struct rtc_wkalrm *alarm)
288 {
289         struct rtc_time *const tm = &alarm->time;
290         u8 regs[ISL1208_ALARM_SECTION_LEN] = { 0, };
291         int sr;
292
293         sr = isl1208_i2c_get_sr(client);
294         if (sr < 0) {
295                 dev_err(&client->dev, "%s: reading SR failed\n", __func__);
296                 return sr;
297         }
298
299         sr = isl1208_i2c_read_regs(client, ISL1208_REG_SCA, regs,
300                                    ISL1208_ALARM_SECTION_LEN);
301         if (sr < 0) {
302                 dev_err(&client->dev, "%s: reading alarm section failed\n",
303                         __func__);
304                 return sr;
305         }
306
307         /* MSB of each alarm register is an enable bit */
308         tm->tm_sec = bcd2bin(regs[ISL1208_REG_SCA - ISL1208_REG_SCA] & 0x7f);
309         tm->tm_min = bcd2bin(regs[ISL1208_REG_MNA - ISL1208_REG_SCA] & 0x7f);
310         tm->tm_hour = bcd2bin(regs[ISL1208_REG_HRA - ISL1208_REG_SCA] & 0x3f);
311         tm->tm_mday = bcd2bin(regs[ISL1208_REG_DTA - ISL1208_REG_SCA] & 0x3f);
312         tm->tm_mon =
313                 bcd2bin(regs[ISL1208_REG_MOA - ISL1208_REG_SCA] & 0x1f) - 1;
314         tm->tm_wday = bcd2bin(regs[ISL1208_REG_DWA - ISL1208_REG_SCA] & 0x03);
315
316         return 0;
317 }
318
319 static int
320 isl1208_rtc_read_time(struct device *dev, struct rtc_time *tm)
321 {
322         return isl1208_i2c_read_time(to_i2c_client(dev), tm);
323 }
324
325 static int
326 isl1208_i2c_set_time(struct i2c_client *client, struct rtc_time const *tm)
327 {
328         int sr;
329         u8 regs[ISL1208_RTC_SECTION_LEN] = { 0, };
330
331         /* The clock has an 8 bit wide bcd-coded register (they never learn)
332          * for the year. tm_year is an offset from 1900 and we are interested
333          * in the 2000-2099 range, so any value less than 100 is invalid.
334          */
335         if (tm->tm_year < 100)
336                 return -EINVAL;
337
338         regs[ISL1208_REG_SC] = bin2bcd(tm->tm_sec);
339         regs[ISL1208_REG_MN] = bin2bcd(tm->tm_min);
340         regs[ISL1208_REG_HR] = bin2bcd(tm->tm_hour) | ISL1208_REG_HR_MIL;
341
342         regs[ISL1208_REG_DT] = bin2bcd(tm->tm_mday);
343         regs[ISL1208_REG_MO] = bin2bcd(tm->tm_mon + 1);
344         regs[ISL1208_REG_YR] = bin2bcd(tm->tm_year - 100);
345
346         regs[ISL1208_REG_DW] = bin2bcd(tm->tm_wday & 7);
347
348         sr = isl1208_i2c_get_sr(client);
349         if (sr < 0) {
350                 dev_err(&client->dev, "%s: reading SR failed\n", __func__);
351                 return sr;
352         }
353
354         /* set WRTC */
355         sr = i2c_smbus_write_byte_data(client, ISL1208_REG_SR,
356                                        sr | ISL1208_REG_SR_WRTC);
357         if (sr < 0) {
358                 dev_err(&client->dev, "%s: writing SR failed\n", __func__);
359                 return sr;
360         }
361
362         /* write RTC registers */
363         sr = isl1208_i2c_set_regs(client, 0, regs, ISL1208_RTC_SECTION_LEN);
364         if (sr < 0) {
365                 dev_err(&client->dev, "%s: writing RTC section failed\n",
366                         __func__);
367                 return sr;
368         }
369
370         /* clear WRTC again */
371         sr = i2c_smbus_write_byte_data(client, ISL1208_REG_SR,
372                                        sr & ~ISL1208_REG_SR_WRTC);
373         if (sr < 0) {
374                 dev_err(&client->dev, "%s: writing SR failed\n", __func__);
375                 return sr;
376         }
377
378         return 0;
379 }
380
381
382 static int
383 isl1208_rtc_set_time(struct device *dev, struct rtc_time *tm)
384 {
385         return isl1208_i2c_set_time(to_i2c_client(dev), tm);
386 }
387
388 static int
389 isl1208_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
390 {
391         return isl1208_i2c_read_alarm(to_i2c_client(dev), alarm);
392 }
393
394 static const struct rtc_class_ops isl1208_rtc_ops = {
395         .proc = isl1208_rtc_proc,
396         .read_time = isl1208_rtc_read_time,
397         .set_time = isl1208_rtc_set_time,
398         .read_alarm = isl1208_rtc_read_alarm,
399         /*.set_alarm    = isl1208_rtc_set_alarm, */
400 };
401
402 /* sysfs interface */
403
404 static ssize_t
405 isl1208_sysfs_show_atrim(struct device *dev,
406                          struct device_attribute *attr, char *buf)
407 {
408         int atr = isl1208_i2c_get_atr(to_i2c_client(dev));
409         if (atr < 0)
410                 return atr;
411
412         return sprintf(buf, "%d.%.2d pF\n", atr >> 2, (atr & 0x3) * 25);
413 }
414
415 static DEVICE_ATTR(atrim, S_IRUGO, isl1208_sysfs_show_atrim, NULL);
416
417 static ssize_t
418 isl1208_sysfs_show_dtrim(struct device *dev,
419                          struct device_attribute *attr, char *buf)
420 {
421         int dtr = isl1208_i2c_get_dtr(to_i2c_client(dev));
422         if (dtr < 0)
423                 return dtr;
424
425         return sprintf(buf, "%d ppm\n", dtr);
426 }
427
428 static DEVICE_ATTR(dtrim, S_IRUGO, isl1208_sysfs_show_dtrim, NULL);
429
430 static ssize_t
431 isl1208_sysfs_show_usr(struct device *dev,
432                        struct device_attribute *attr, char *buf)
433 {
434         int usr = isl1208_i2c_get_usr(to_i2c_client(dev));
435         if (usr < 0)
436                 return usr;
437
438         return sprintf(buf, "0x%.4x\n", usr);
439 }
440
441 static ssize_t
442 isl1208_sysfs_store_usr(struct device *dev,
443                         struct device_attribute *attr,
444                         const char *buf, size_t count)
445 {
446         int usr = -1;
447
448         if (buf[0] == '0' && (buf[1] == 'x' || buf[1] == 'X')) {
449                 if (sscanf(buf, "%x", &usr) != 1)
450                         return -EINVAL;
451         } else {
452                 if (sscanf(buf, "%d", &usr) != 1)
453                         return -EINVAL;
454         }
455
456         if (usr < 0 || usr > 0xffff)
457                 return -EINVAL;
458
459         return isl1208_i2c_set_usr(to_i2c_client(dev), usr) ? -EIO : count;
460 }
461
462 static DEVICE_ATTR(usr, S_IRUGO | S_IWUSR, isl1208_sysfs_show_usr,
463                    isl1208_sysfs_store_usr);
464
465 static int
466 isl1208_sysfs_register(struct device *dev)
467 {
468         int err;
469
470         err = device_create_file(dev, &dev_attr_atrim);
471         if (err)
472                 return err;
473
474         err = device_create_file(dev, &dev_attr_dtrim);
475         if (err) {
476                 device_remove_file(dev, &dev_attr_atrim);
477                 return err;
478         }
479
480         err = device_create_file(dev, &dev_attr_usr);
481         if (err) {
482                 device_remove_file(dev, &dev_attr_atrim);
483                 device_remove_file(dev, &dev_attr_dtrim);
484         }
485
486         return 0;
487 }
488
489 static int
490 isl1208_sysfs_unregister(struct device *dev)
491 {
492         device_remove_file(dev, &dev_attr_dtrim);
493         device_remove_file(dev, &dev_attr_atrim);
494         device_remove_file(dev, &dev_attr_usr);
495
496         return 0;
497 }
498
499 static int
500 isl1208_probe(struct i2c_client *client, const struct i2c_device_id *id)
501 {
502         int rc = 0;
503         struct rtc_device *rtc;
504
505         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
506                 return -ENODEV;
507
508         if (isl1208_i2c_validate_client(client) < 0)
509                 return -ENODEV;
510
511         dev_info(&client->dev,
512                  "chip found, driver version " DRV_VERSION "\n");
513
514         rtc = rtc_device_register(isl1208_driver.driver.name,
515                                   &client->dev, &isl1208_rtc_ops,
516                                   THIS_MODULE);
517         if (IS_ERR(rtc))
518                 return PTR_ERR(rtc);
519
520         i2c_set_clientdata(client, rtc);
521
522         rc = isl1208_i2c_get_sr(client);
523         if (rc < 0) {
524                 dev_err(&client->dev, "reading status failed\n");
525                 goto exit_unregister;
526         }
527
528         if (rc & ISL1208_REG_SR_RTCF)
529                 dev_warn(&client->dev, "rtc power failure detected, "
530                          "please set clock.\n");
531
532         rc = isl1208_sysfs_register(&client->dev);
533         if (rc)
534                 goto exit_unregister;
535
536         return 0;
537
538 exit_unregister:
539         rtc_device_unregister(rtc);
540
541         return rc;
542 }
543
544 static int
545 isl1208_remove(struct i2c_client *client)
546 {
547         struct rtc_device *rtc = i2c_get_clientdata(client);
548
549         isl1208_sysfs_unregister(&client->dev);
550         rtc_device_unregister(rtc);
551
552         return 0;
553 }
554
555 static const struct i2c_device_id isl1208_id[] = {
556         { "isl1208", 0 },
557         { }
558 };
559 MODULE_DEVICE_TABLE(i2c, isl1208_id);
560
561 static struct i2c_driver isl1208_driver = {
562         .driver = {
563                    .name = "rtc-isl1208",
564                    },
565         .probe = isl1208_probe,
566         .remove = isl1208_remove,
567         .id_table = isl1208_id,
568 };
569
570 static int __init
571 isl1208_init(void)
572 {
573         return i2c_add_driver(&isl1208_driver);
574 }
575
576 static void __exit
577 isl1208_exit(void)
578 {
579         i2c_del_driver(&isl1208_driver);
580 }
581
582 MODULE_AUTHOR("Herbert Valerio Riedel <hvr@gnu.org>");
583 MODULE_DESCRIPTION("Intersil ISL1208 RTC driver");
584 MODULE_LICENSE("GPL");
585 MODULE_VERSION(DRV_VERSION);
586
587 module_init(isl1208_init);
588 module_exit(isl1208_exit);