source: src/linux/universal/linux-3.18/drivers/rtc/rtc-s35390a.c @ 31885

Last change on this file since 31885 was 31885, checked in by brainslayer, 5 weeks ago

update

File size: 12.8 KB
Line 
1/*
2 * Seiko Instruments S-35390A RTC Driver
3 *
4 * Copyright (c) 2007 Byron Bradley
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11
12#include <linux/module.h>
13#include <linux/rtc.h>
14#include <linux/i2c.h>
15#include <linux/bitrev.h>
16#include <linux/bcd.h>
17#include <linux/slab.h>
18#include <linux/delay.h>
19
20#define S35390A_CMD_STATUS1     0
21#define S35390A_CMD_STATUS2     1
22#define S35390A_CMD_TIME1       2
23#define S35390A_CMD_TIME2       3
24#define S35390A_CMD_INT2_REG1   5
25
26#define S35390A_BYTE_YEAR       0
27#define S35390A_BYTE_MONTH      1
28#define S35390A_BYTE_DAY        2
29#define S35390A_BYTE_WDAY       3
30#define S35390A_BYTE_HOURS      4
31#define S35390A_BYTE_MINS       5
32#define S35390A_BYTE_SECS       6
33
34#define S35390A_ALRM_BYTE_WDAY  0
35#define S35390A_ALRM_BYTE_HOURS 1
36#define S35390A_ALRM_BYTE_MINS  2
37
38/* flags for STATUS1 */
39#define S35390A_FLAG_POC        0x01
40#define S35390A_FLAG_BLD        0x02
41#define S35390A_FLAG_INT2       0x04
42#define S35390A_FLAG_24H        0x40
43#define S35390A_FLAG_RESET      0x80
44
45/* flag for STATUS2 */
46#define S35390A_FLAG_TEST       0x01
47
48#define S35390A_INT2_MODE_MASK          0xF0
49
50#define S35390A_INT2_MODE_NOINTR        0x00
51#define S35390A_INT2_MODE_FREQ          0x10
52#define S35390A_INT2_MODE_ALARM         0x40
53#define S35390A_INT2_MODE_PMIN_EDG      0x20
54
55static const struct i2c_device_id s35390a_id[] = {
56        { "s35390a", 0 },
57        { }
58};
59MODULE_DEVICE_TABLE(i2c, s35390a_id);
60
61struct s35390a {
62        struct i2c_client *client[8];
63        struct rtc_device *rtc;
64        int twentyfourhour;
65};
66
67static int s35390a_set_reg(struct s35390a *s35390a, int reg, char *buf, int len)
68{
69        struct i2c_client *client = s35390a->client[reg];
70        struct i2c_msg msg[] = {
71                {
72                        .addr = client->addr,
73                        .len = len,
74                        .buf = buf
75                },
76        };
77
78        if ((i2c_transfer(client->adapter, msg, 1)) != 1)
79                return -EIO;
80
81        return 0;
82}
83
84static int s35390a_get_reg(struct s35390a *s35390a, int reg, char *buf, int len)
85{
86        struct i2c_client *client = s35390a->client[reg];
87        struct i2c_msg msg[] = {
88                {
89                        .addr = client->addr,
90                        .flags = I2C_M_RD,
91                        .len = len,
92                        .buf = buf
93                },
94        };
95
96        if ((i2c_transfer(client->adapter, msg, 1)) != 1)
97                return -EIO;
98
99        return 0;
100}
101
102/*
103 * Returns <0 on error, 0 if rtc is setup fine and 1 if the chip was reset.
104 * To keep the information if an irq is pending, pass the value read from
105 * STATUS1 to the caller.
106 */
107static int s35390a_reset(struct s35390a *s35390a, char *status1)
108{
109        char buf;
110        int ret;
111        unsigned initcount = 0;
112
113        ret = s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, status1, 1);
114        if (ret < 0)
115                return ret;
116
117        if (*status1 & S35390A_FLAG_POC)
118                /*
119                 * Do not communicate for 0.5 seconds since the power-on
120                 * detection circuit is in operation.
121                 */
122                msleep(500);
123        else if (!(*status1 & S35390A_FLAG_BLD))
124                /*
125                 * If both POC and BLD are unset everything is fine.
126                 */
127                return 0;
128
129        /*
130         * At least one of POC and BLD are set, so reinitialise chip. Keeping
131         * this information in the hardware to know later that the time isn't
132         * valid is unfortunately not possible because POC and BLD are cleared
133         * on read. So the reset is best done now.
134         *
135         * The 24H bit is kept over reset, so set it already here.
136         */
137initialize:
138        *status1 = S35390A_FLAG_24H;
139        buf = S35390A_FLAG_RESET | S35390A_FLAG_24H;
140        ret = s35390a_set_reg(s35390a, S35390A_CMD_STATUS1, &buf, 1);
141
142        if (ret < 0)
143                return ret;
144
145        ret = s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, &buf, 1);
146        if (ret < 0)
147                return ret;
148
149        if (buf & (S35390A_FLAG_POC | S35390A_FLAG_BLD)) {
150                /* Try up to five times to reset the chip */
151                if (initcount < 5) {
152                        ++initcount;
153                        goto initialize;
154                } else
155                        return -EIO;
156        }
157
158        return 1;
159}
160
161static int s35390a_disable_test_mode(struct s35390a *s35390a)
162{
163        char buf[1];
164
165        if (s35390a_get_reg(s35390a, S35390A_CMD_STATUS2, buf, sizeof(buf)) < 0)
166                return -EIO;
167
168        if (!(buf[0] & S35390A_FLAG_TEST))
169                return 0;
170
171        buf[0] &= ~S35390A_FLAG_TEST;
172        return s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, buf, sizeof(buf));
173}
174
175static char s35390a_hr2reg(struct s35390a *s35390a, int hour)
176{
177        if (s35390a->twentyfourhour)
178                return bin2bcd(hour);
179
180        if (hour < 12)
181                return bin2bcd(hour);
182
183        return 0x40 | bin2bcd(hour - 12);
184}
185
186static int s35390a_reg2hr(struct s35390a *s35390a, char reg)
187{
188        unsigned hour;
189
190        if (s35390a->twentyfourhour)
191                return bcd2bin(reg & 0x3f);
192
193        hour = bcd2bin(reg & 0x3f);
194        if (reg & 0x40)
195                hour += 12;
196
197        return hour;
198}
199
200static int s35390a_set_datetime(struct i2c_client *client, struct rtc_time *tm)
201{
202        struct s35390a  *s35390a = i2c_get_clientdata(client);
203        int i, err;
204        char buf[7];
205
206        dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d mday=%d, "
207                "mon=%d, year=%d, wday=%d\n", __func__, tm->tm_sec,
208                tm->tm_min, tm->tm_hour, tm->tm_mday, tm->tm_mon, tm->tm_year,
209                tm->tm_wday);
210
211        buf[S35390A_BYTE_YEAR] = bin2bcd(tm->tm_year - 100);
212        buf[S35390A_BYTE_MONTH] = bin2bcd(tm->tm_mon + 1);
213        buf[S35390A_BYTE_DAY] = bin2bcd(tm->tm_mday);
214        buf[S35390A_BYTE_WDAY] = bin2bcd(tm->tm_wday);
215        buf[S35390A_BYTE_HOURS] = s35390a_hr2reg(s35390a, tm->tm_hour);
216        buf[S35390A_BYTE_MINS] = bin2bcd(tm->tm_min);
217        buf[S35390A_BYTE_SECS] = bin2bcd(tm->tm_sec);
218
219        /* This chip expects the bits of each byte to be in reverse order */
220        for (i = 0; i < 7; ++i)
221                buf[i] = bitrev8(buf[i]);
222
223        err = s35390a_set_reg(s35390a, S35390A_CMD_TIME1, buf, sizeof(buf));
224
225        return err;
226}
227
228static int s35390a_get_datetime(struct i2c_client *client, struct rtc_time *tm)
229{
230        struct s35390a *s35390a = i2c_get_clientdata(client);
231        char buf[7];
232        int i, err;
233
234        err = s35390a_get_reg(s35390a, S35390A_CMD_TIME1, buf, sizeof(buf));
235        if (err < 0)
236                return err;
237
238        /* This chip returns the bits of each byte in reverse order */
239        for (i = 0; i < 7; ++i)
240                buf[i] = bitrev8(buf[i]);
241
242        tm->tm_sec = bcd2bin(buf[S35390A_BYTE_SECS]);
243        tm->tm_min = bcd2bin(buf[S35390A_BYTE_MINS]);
244        tm->tm_hour = s35390a_reg2hr(s35390a, buf[S35390A_BYTE_HOURS]);
245        tm->tm_wday = bcd2bin(buf[S35390A_BYTE_WDAY]);
246        tm->tm_mday = bcd2bin(buf[S35390A_BYTE_DAY]);
247        tm->tm_mon = bcd2bin(buf[S35390A_BYTE_MONTH]) - 1;
248        tm->tm_year = bcd2bin(buf[S35390A_BYTE_YEAR]) + 100;
249
250        dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, mday=%d, "
251                "mon=%d, year=%d, wday=%d\n", __func__, tm->tm_sec,
252                tm->tm_min, tm->tm_hour, tm->tm_mday, tm->tm_mon, tm->tm_year,
253                tm->tm_wday);
254
255        return rtc_valid_tm(tm);
256}
257
258static int s35390a_set_alarm(struct i2c_client *client, struct rtc_wkalrm *alm)
259{
260        struct s35390a *s35390a = i2c_get_clientdata(client);
261        char buf[3], sts = 0;
262        int err, i;
263
264        dev_dbg(&client->dev, "%s: alm is secs=%d, mins=%d, hours=%d mday=%d, "\
265                "mon=%d, year=%d, wday=%d\n", __func__, alm->time.tm_sec,
266                alm->time.tm_min, alm->time.tm_hour, alm->time.tm_mday,
267                alm->time.tm_mon, alm->time.tm_year, alm->time.tm_wday);
268
269        /* disable interrupt */
270        err = s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, &sts, sizeof(sts));
271        if (err < 0)
272                return err;
273
274        /* clear pending interrupt, if any */
275        err = s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, &sts, sizeof(sts));
276        if (err < 0)
277                return err;
278
279        if (alm->enabled)
280                sts = S35390A_INT2_MODE_ALARM;
281        else
282                sts = S35390A_INT2_MODE_NOINTR;
283
284        /* This chip expects the bits of each byte to be in reverse order */
285        sts = bitrev8(sts);
286
287        /* set interupt mode*/
288        err = s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, &sts, sizeof(sts));
289        if (err < 0)
290                return err;
291
292        if (alm->time.tm_wday != -1)
293                buf[S35390A_ALRM_BYTE_WDAY] = bin2bcd(alm->time.tm_wday) | 0x80;
294        else
295                buf[S35390A_ALRM_BYTE_WDAY] = 0;
296
297        buf[S35390A_ALRM_BYTE_HOURS] = s35390a_hr2reg(s35390a,
298                        alm->time.tm_hour) | 0x80;
299        buf[S35390A_ALRM_BYTE_MINS] = bin2bcd(alm->time.tm_min) | 0x80;
300
301        if (alm->time.tm_hour >= 12)
302                buf[S35390A_ALRM_BYTE_HOURS] |= 0x40;
303
304        for (i = 0; i < 3; ++i)
305                buf[i] = bitrev8(buf[i]);
306
307        err = s35390a_set_reg(s35390a, S35390A_CMD_INT2_REG1, buf,
308                                                                sizeof(buf));
309
310        return err;
311}
312
313static int s35390a_read_alarm(struct i2c_client *client, struct rtc_wkalrm *alm)
314{
315        struct s35390a *s35390a = i2c_get_clientdata(client);
316        char buf[3], sts;
317        int i, err;
318
319        /*
320         * initialize all members to -1 to signal the core that they are not
321         * defined by the hardware.
322         */
323        alm->time.tm_sec = -1;
324        alm->time.tm_min = -1;
325        alm->time.tm_hour = -1;
326        alm->time.tm_mday = -1;
327        alm->time.tm_mon = -1;
328        alm->time.tm_year = -1;
329        alm->time.tm_wday = -1;
330        alm->time.tm_yday = -1;
331        alm->time.tm_isdst = -1;
332
333        err = s35390a_get_reg(s35390a, S35390A_CMD_STATUS2, &sts, sizeof(sts));
334        if (err < 0)
335                return err;
336
337        if ((bitrev8(sts) & S35390A_INT2_MODE_MASK) != S35390A_INT2_MODE_ALARM) {
338                /*
339                 * When the alarm isn't enabled, the register to configure
340                 * the alarm time isn't accessible.
341                 */
342                alm->enabled = 0;
343                return 0;
344        } else {
345                alm->enabled = 1;
346        }
347
348        err = s35390a_get_reg(s35390a, S35390A_CMD_INT2_REG1, buf, sizeof(buf));
349        if (err < 0)
350                return err;
351
352        /* This chip returns the bits of each byte in reverse order */
353        for (i = 0; i < 3; ++i)
354                buf[i] = bitrev8(buf[i]);
355
356        /*
357         * B0 of the three matching registers is an enable flag. Iff it is set
358         * the configured value is used for matching.
359         */
360        if (buf[S35390A_ALRM_BYTE_WDAY] & 0x80)
361                alm->time.tm_wday =
362                        bcd2bin(buf[S35390A_ALRM_BYTE_WDAY] & ~0x80);
363
364        if (buf[S35390A_ALRM_BYTE_HOURS] & 0x80)
365                alm->time.tm_hour =
366                        s35390a_reg2hr(s35390a,
367                                       buf[S35390A_ALRM_BYTE_HOURS] & ~0x80);
368
369        if (buf[S35390A_ALRM_BYTE_MINS] & 0x80)
370                alm->time.tm_min = bcd2bin(buf[S35390A_ALRM_BYTE_MINS] & ~0x80);
371
372        /* alarm triggers always at s=0 */
373        alm->time.tm_sec = 0;
374
375        dev_dbg(&client->dev, "%s: alm is mins=%d, hours=%d, wday=%d\n",
376                        __func__, alm->time.tm_min, alm->time.tm_hour,
377                        alm->time.tm_wday);
378
379        return 0;
380}
381
382static int s35390a_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
383{
384        return s35390a_read_alarm(to_i2c_client(dev), alm);
385}
386
387static int s35390a_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
388{
389        return s35390a_set_alarm(to_i2c_client(dev), alm);
390}
391
392static int s35390a_rtc_read_time(struct device *dev, struct rtc_time *tm)
393{
394        return s35390a_get_datetime(to_i2c_client(dev), tm);
395}
396
397static int s35390a_rtc_set_time(struct device *dev, struct rtc_time *tm)
398{
399        return s35390a_set_datetime(to_i2c_client(dev), tm);
400}
401
402static const struct rtc_class_ops s35390a_rtc_ops = {
403        .read_time      = s35390a_rtc_read_time,
404        .set_time       = s35390a_rtc_set_time,
405        .set_alarm      = s35390a_rtc_set_alarm,
406        .read_alarm     = s35390a_rtc_read_alarm,
407
408};
409
410static struct i2c_driver s35390a_driver;
411
412static int s35390a_probe(struct i2c_client *client,
413                         const struct i2c_device_id *id)
414{
415        int err, err_reset;
416        unsigned int i;
417        struct s35390a *s35390a;
418        struct rtc_time tm;
419        char buf, status1;
420
421        if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
422                err = -ENODEV;
423                goto exit;
424        }
425
426        s35390a = devm_kzalloc(&client->dev, sizeof(struct s35390a),
427                                GFP_KERNEL);
428        if (!s35390a) {
429                err = -ENOMEM;
430                goto exit;
431        }
432
433        s35390a->client[0] = client;
434        i2c_set_clientdata(client, s35390a);
435
436        /* This chip uses multiple addresses, use dummy devices for them */
437        for (i = 1; i < 8; ++i) {
438                s35390a->client[i] = i2c_new_dummy(client->adapter,
439                                        client->addr + i);
440                if (!s35390a->client[i]) {
441                        dev_err(&client->dev, "Address %02x unavailable\n",
442                                                client->addr + i);
443                        err = -EBUSY;
444                        goto exit_dummy;
445                }
446        }
447
448        err_reset = s35390a_reset(s35390a, &status1);
449        if (err_reset < 0) {
450                err = err_reset;
451                dev_err(&client->dev, "error resetting chip\n");
452                goto exit_dummy;
453        }
454
455        if (status1 & S35390A_FLAG_24H)
456                s35390a->twentyfourhour = 1;
457        else
458                s35390a->twentyfourhour = 0;
459
460        if (status1 & S35390A_FLAG_INT2) {
461                /* disable alarm (and maybe test mode) */
462                buf = 0;
463                err = s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, &buf, 1);
464                if (err < 0) {
465                        dev_err(&client->dev, "error disabling alarm");
466                        goto exit_dummy;
467                }
468        } else {
469                err = s35390a_disable_test_mode(s35390a);
470                if (err < 0) {
471                        dev_err(&client->dev, "error disabling test mode\n");
472                        goto exit_dummy;
473                }
474        }
475
476        if (err_reset > 0 || s35390a_get_datetime(client, &tm) < 0)
477                dev_warn(&client->dev, "clock needs to be set\n");
478
479        device_set_wakeup_capable(&client->dev, 1);
480
481        s35390a->rtc = devm_rtc_device_register(&client->dev,
482                                        s35390a_driver.driver.name,
483                                        &s35390a_rtc_ops, THIS_MODULE);
484
485        if (IS_ERR(s35390a->rtc)) {
486                err = PTR_ERR(s35390a->rtc);
487                goto exit_dummy;
488        }
489
490        if (status1 & S35390A_FLAG_INT2)
491                rtc_update_irq(s35390a->rtc, 1, RTC_AF);
492
493        return 0;
494
495exit_dummy:
496        for (i = 1; i < 8; ++i)
497                if (s35390a->client[i])
498                        i2c_unregister_device(s35390a->client[i]);
499
500exit:
501        return err;
502}
503
504static int s35390a_remove(struct i2c_client *client)
505{
506        unsigned int i;
507        struct s35390a *s35390a = i2c_get_clientdata(client);
508
509        for (i = 1; i < 8; ++i)
510                if (s35390a->client[i])
511                        i2c_unregister_device(s35390a->client[i]);
512
513        return 0;
514}
515
516static struct i2c_driver s35390a_driver = {
517        .driver         = {
518                .name   = "rtc-s35390a",
519        },
520        .probe          = s35390a_probe,
521        .remove         = s35390a_remove,
522        .id_table       = s35390a_id,
523};
524
525module_i2c_driver(s35390a_driver);
526
527MODULE_AUTHOR("Byron Bradley <byron.bbradley@gmail.com>");
528MODULE_DESCRIPTION("S35390A RTC driver");
529MODULE_LICENSE("GPL");
Note: See TracBrowser for help on using the repository browser.