a81adab6e515849306d9fb9e245eebc0e8532784
[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         regs[ISL1208_REG_SC] = BIN2BCD(tm->tm_sec);
332         regs[ISL1208_REG_MN] = BIN2BCD(tm->tm_min);
333         regs[ISL1208_REG_HR] = BIN2BCD(tm->tm_hour) | ISL1208_REG_HR_MIL;
334
335         regs[ISL1208_REG_DT] = BIN2BCD(tm->tm_mday);
336         regs[ISL1208_REG_MO] = BIN2BCD(tm->tm_mon + 1);
337         regs[ISL1208_REG_YR] = BIN2BCD(tm->tm_year - 100);
338
339         regs[ISL1208_REG_DW] = BIN2BCD(tm->tm_wday & 7);
340
341         sr = isl1208_i2c_get_sr(client);
342         if (sr < 0) {
343                 dev_err(&client->dev, "%s: reading SR failed\n", __func__);
344                 return sr;
345         }
346
347         /* set WRTC */
348         sr = i2c_smbus_write_byte_data(client, ISL1208_REG_SR,
349                                        sr | ISL1208_REG_SR_WRTC);
350         if (sr < 0) {
351                 dev_err(&client->dev, "%s: writing SR failed\n", __func__);
352                 return sr;
353         }
354
355         /* write RTC registers */
356         sr = isl1208_i2c_set_regs(client, 0, regs, ISL1208_RTC_SECTION_LEN);
357         if (sr < 0) {
358                 dev_err(&client->dev, "%s: writing RTC section failed\n",
359                         __func__);
360                 return sr;
361         }
362
363         /* clear WRTC again */
364         sr = i2c_smbus_write_byte_data(client, ISL1208_REG_SR,
365                                        sr & ~ISL1208_REG_SR_WRTC);
366         if (sr < 0) {
367                 dev_err(&client->dev, "%s: writing SR failed\n", __func__);
368                 return sr;
369         }
370
371         return 0;
372 }
373
374
375 static int
376 isl1208_rtc_set_time(struct device *dev, struct rtc_time *tm)
377 {
378         return isl1208_i2c_set_time(to_i2c_client(dev), tm);
379 }
380
381 static int
382 isl1208_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
383 {
384         return isl1208_i2c_read_alarm(to_i2c_client(dev), alarm);
385 }
386
387 static const struct rtc_class_ops isl1208_rtc_ops = {
388         .proc = isl1208_rtc_proc,
389         .read_time = isl1208_rtc_read_time,
390         .set_time = isl1208_rtc_set_time,
391         .read_alarm = isl1208_rtc_read_alarm,
392         /*.set_alarm    = isl1208_rtc_set_alarm, */
393 };
394
395 /* sysfs interface */
396
397 static ssize_t
398 isl1208_sysfs_show_atrim(struct device *dev,
399                          struct device_attribute *attr, char *buf)
400 {
401         int atr = isl1208_i2c_get_atr(to_i2c_client(dev));
402         if (atr < 0)
403                 return atr;
404
405         return sprintf(buf, "%d.%.2d pF\n", atr >> 2, (atr & 0x3) * 25);
406 }
407
408 static DEVICE_ATTR(atrim, S_IRUGO, isl1208_sysfs_show_atrim, NULL);
409
410 static ssize_t
411 isl1208_sysfs_show_dtrim(struct device *dev,
412                          struct device_attribute *attr, char *buf)
413 {
414         int dtr = isl1208_i2c_get_dtr(to_i2c_client(dev));
415         if (dtr < 0)
416                 return dtr;
417
418         return sprintf(buf, "%d ppm\n", dtr);
419 }
420
421 static DEVICE_ATTR(dtrim, S_IRUGO, isl1208_sysfs_show_dtrim, NULL);
422
423 static ssize_t
424 isl1208_sysfs_show_usr(struct device *dev,
425                        struct device_attribute *attr, char *buf)
426 {
427         int usr = isl1208_i2c_get_usr(to_i2c_client(dev));
428         if (usr < 0)
429                 return usr;
430
431         return sprintf(buf, "0x%.4x\n", usr);
432 }
433
434 static ssize_t
435 isl1208_sysfs_store_usr(struct device *dev,
436                         struct device_attribute *attr,
437                         const char *buf, size_t count)
438 {
439         int usr = -1;
440
441         if (buf[0] == '0' && (buf[1] == 'x' || buf[1] == 'X')) {
442                 if (sscanf(buf, "%x", &usr) != 1)
443                         return -EINVAL;
444         } else {
445                 if (sscanf(buf, "%d", &usr) != 1)
446                         return -EINVAL;
447         }
448
449         if (usr < 0 || usr > 0xffff)
450                 return -EINVAL;
451
452         return isl1208_i2c_set_usr(to_i2c_client(dev), usr) ? -EIO : count;
453 }
454
455 static DEVICE_ATTR(usr, S_IRUGO | S_IWUSR, isl1208_sysfs_show_usr,
456                    isl1208_sysfs_store_usr);
457
458 static int
459 isl1208_sysfs_register(struct device *dev)
460 {
461         int err;
462
463         err = device_create_file(dev, &dev_attr_atrim);
464         if (err)
465                 return err;
466
467         err = device_create_file(dev, &dev_attr_dtrim);
468         if (err) {
469                 device_remove_file(dev, &dev_attr_atrim);
470                 return err;
471         }
472
473         err = device_create_file(dev, &dev_attr_usr);
474         if (err) {
475                 device_remove_file(dev, &dev_attr_atrim);
476                 device_remove_file(dev, &dev_attr_dtrim);
477         }
478
479         return 0;
480 }
481
482 static int
483 isl1208_sysfs_unregister(struct device *dev)
484 {
485         device_remove_file(dev, &dev_attr_dtrim);
486         device_remove_file(dev, &dev_attr_atrim);
487         device_remove_file(dev, &dev_attr_usr);
488
489         return 0;
490 }
491
492 static int
493 isl1208_probe(struct i2c_client *client, const struct i2c_device_id *id)
494 {
495         int rc = 0;
496         struct rtc_device *rtc;
497
498         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
499                 return -ENODEV;
500
501         if (isl1208_i2c_validate_client(client) < 0)
502                 return -ENODEV;
503
504         dev_info(&client->dev,
505                  "chip found, driver version " DRV_VERSION "\n");
506
507         rtc = rtc_device_register(isl1208_driver.driver.name,
508                                   &client->dev, &isl1208_rtc_ops,
509                                   THIS_MODULE);
510         if (IS_ERR(rtc))
511                 return PTR_ERR(rtc);
512
513         i2c_set_clientdata(client, rtc);
514
515         rc = isl1208_i2c_get_sr(client);
516         if (rc < 0) {
517                 dev_err(&client->dev, "reading status failed\n");
518                 goto exit_unregister;
519         }
520
521         if (rc & ISL1208_REG_SR_RTCF)
522                 dev_warn(&client->dev, "rtc power failure detected, "
523                          "please set clock.\n");
524
525         rc = isl1208_sysfs_register(&client->dev);
526         if (rc)
527                 goto exit_unregister;
528
529         return 0;
530
531 exit_unregister:
532         rtc_device_unregister(rtc);
533
534         return rc;
535 }
536
537 static int
538 isl1208_remove(struct i2c_client *client)
539 {
540         struct rtc_device *rtc = i2c_get_clientdata(client);
541
542         isl1208_sysfs_unregister(&client->dev);
543         rtc_device_unregister(rtc);
544
545         return 0;
546 }
547
548 static const struct i2c_device_id isl1208_id[] = {
549         { "isl1208", 0 },
550         { }
551 };
552 MODULE_DEVICE_TABLE(i2c, isl1208_id);
553
554 static struct i2c_driver isl1208_driver = {
555         .driver = {
556                    .name = "rtc-isl1208",
557                    },
558         .probe = isl1208_probe,
559         .remove = isl1208_remove,
560         .id_table = isl1208_id,
561 };
562
563 static int __init
564 isl1208_init(void)
565 {
566         return i2c_add_driver(&isl1208_driver);
567 }
568
569 static void __exit
570 isl1208_exit(void)
571 {
572         i2c_del_driver(&isl1208_driver);
573 }
574
575 MODULE_AUTHOR("Herbert Valerio Riedel <hvr@gnu.org>");
576 MODULE_DESCRIPTION("Intersil ISL1208 RTC driver");
577 MODULE_LICENSE("GPL");
578 MODULE_VERSION(DRV_VERSION);
579
580 module_init(isl1208_init);
581 module_exit(isl1208_exit);