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Linux/drivers/rtc/rtc-pcf8563.c

  1 /*
  2  * An I2C driver for the Philips PCF8563 RTC
  3  * Copyright 2005-06 Tower Technologies
  4  *
  5  * Author: Alessandro Zummo <a.zummo@towertech.it>
  6  * Maintainers: http://www.nslu2-linux.org/
  7  *
  8  * based on the other drivers in this same directory.
  9  *
 10  * http://www.semiconductors.philips.com/acrobat/datasheets/PCF8563-04.pdf
 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/slab.h>
 21 #include <linux/module.h>
 22 #include <linux/of.h>
 23 #include <linux/err.h>
 24 
 25 #define DRV_VERSION "0.4.3"
 26 
 27 #define PCF8563_REG_ST1         0x00 /* status */
 28 #define PCF8563_REG_ST2         0x01
 29 #define PCF8563_BIT_AIE         (1 << 1)
 30 #define PCF8563_BIT_AF          (1 << 3)
 31 #define PCF8563_BITS_ST2_N      (7 << 5)
 32 
 33 #define PCF8563_REG_SC          0x02 /* datetime */
 34 #define PCF8563_REG_MN          0x03
 35 #define PCF8563_REG_HR          0x04
 36 #define PCF8563_REG_DM          0x05
 37 #define PCF8563_REG_DW          0x06
 38 #define PCF8563_REG_MO          0x07
 39 #define PCF8563_REG_YR          0x08
 40 
 41 #define PCF8563_REG_AMN         0x09 /* alarm */
 42 
 43 #define PCF8563_REG_CLKO        0x0D /* clock out */
 44 #define PCF8563_REG_TMRC        0x0E /* timer control */
 45 #define PCF8563_TMRC_ENABLE     BIT(7)
 46 #define PCF8563_TMRC_4096       0
 47 #define PCF8563_TMRC_64         1
 48 #define PCF8563_TMRC_1          2
 49 #define PCF8563_TMRC_1_60       3
 50 #define PCF8563_TMRC_MASK       3
 51 
 52 #define PCF8563_REG_TMR         0x0F /* timer */
 53 
 54 #define PCF8563_SC_LV           0x80 /* low voltage */
 55 #define PCF8563_MO_C            0x80 /* century */
 56 
 57 static struct i2c_driver pcf8563_driver;
 58 
 59 struct pcf8563 {
 60         struct rtc_device *rtc;
 61         /*
 62          * The meaning of MO_C bit varies by the chip type.
 63          * From PCF8563 datasheet: this bit is toggled when the years
 64          * register overflows from 99 to 00
 65          *   0 indicates the century is 20xx
 66          *   1 indicates the century is 19xx
 67          * From RTC8564 datasheet: this bit indicates change of
 68          * century. When the year digit data overflows from 99 to 00,
 69          * this bit is set. By presetting it to 0 while still in the
 70          * 20th century, it will be set in year 2000, ...
 71          * There seems no reliable way to know how the system use this
 72          * bit.  So let's do it heuristically, assuming we are live in
 73          * 1970...2069.
 74          */
 75         int c_polarity; /* 0: MO_C=1 means 19xx, otherwise MO_C=1 means 20xx */
 76         int voltage_low; /* incicates if a low_voltage was detected */
 77 
 78         struct i2c_client *client;
 79 };
 80 
 81 static int pcf8563_read_block_data(struct i2c_client *client, unsigned char reg,
 82                                    unsigned char length, unsigned char *buf)
 83 {
 84         struct i2c_msg msgs[] = {
 85                 {/* setup read ptr */
 86                         .addr = client->addr,
 87                         .len = 1,
 88                         .buf = &reg,
 89                 },
 90                 {
 91                         .addr = client->addr,
 92                         .flags = I2C_M_RD,
 93                         .len = length,
 94                         .buf = buf
 95                 },
 96         };
 97 
 98         if ((i2c_transfer(client->adapter, msgs, 2)) != 2) {
 99                 dev_err(&client->dev, "%s: read error\n", __func__);
100                 return -EIO;
101         }
102 
103         return 0;
104 }
105 
106 static int pcf8563_write_block_data(struct i2c_client *client,
107                                    unsigned char reg, unsigned char length,
108                                    unsigned char *buf)
109 {
110         int i, err;
111 
112         for (i = 0; i < length; i++) {
113                 unsigned char data[2] = { reg + i, buf[i] };
114 
115                 err = i2c_master_send(client, data, sizeof(data));
116                 if (err != sizeof(data)) {
117                         dev_err(&client->dev,
118                                 "%s: err=%d addr=%02x, data=%02x\n",
119                                 __func__, err, data[0], data[1]);
120                         return -EIO;
121                 }
122         }
123 
124         return 0;
125 }
126 
127 static int pcf8563_set_alarm_mode(struct i2c_client *client, bool on)
128 {
129         unsigned char buf;
130         int err;
131 
132         err = pcf8563_read_block_data(client, PCF8563_REG_ST2, 1, &buf);
133         if (err < 0)
134                 return err;
135 
136         if (on)
137                 buf |= PCF8563_BIT_AIE;
138         else
139                 buf &= ~PCF8563_BIT_AIE;
140 
141         buf &= ~(PCF8563_BIT_AF | PCF8563_BITS_ST2_N);
142 
143         err = pcf8563_write_block_data(client, PCF8563_REG_ST2, 1, &buf);
144         if (err < 0) {
145                 dev_err(&client->dev, "%s: write error\n", __func__);
146                 return -EIO;
147         }
148 
149         return 0;
150 }
151 
152 static int pcf8563_get_alarm_mode(struct i2c_client *client, unsigned char *en,
153                                   unsigned char *pen)
154 {
155         unsigned char buf;
156         int err;
157 
158         err = pcf8563_read_block_data(client, PCF8563_REG_ST2, 1, &buf);
159         if (err)
160                 return err;
161 
162         if (en)
163                 *en = !!(buf & PCF8563_BIT_AIE);
164         if (pen)
165                 *pen = !!(buf & PCF8563_BIT_AF);
166 
167         return 0;
168 }
169 
170 static irqreturn_t pcf8563_irq(int irq, void *dev_id)
171 {
172         struct pcf8563 *pcf8563 = i2c_get_clientdata(dev_id);
173         int err;
174         char pending;
175 
176         err = pcf8563_get_alarm_mode(pcf8563->client, NULL, &pending);
177         if (err)
178                 return IRQ_NONE;
179 
180         if (pending) {
181                 rtc_update_irq(pcf8563->rtc, 1, RTC_IRQF | RTC_AF);
182                 pcf8563_set_alarm_mode(pcf8563->client, 1);
183                 return IRQ_HANDLED;
184         }
185 
186         return IRQ_NONE;
187 }
188 
189 /*
190  * In the routines that deal directly with the pcf8563 hardware, we use
191  * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
192  */
193 static int pcf8563_get_datetime(struct i2c_client *client, struct rtc_time *tm)
194 {
195         struct pcf8563 *pcf8563 = i2c_get_clientdata(client);
196         unsigned char buf[9];
197         int err;
198 
199         err = pcf8563_read_block_data(client, PCF8563_REG_ST1, 9, buf);
200         if (err)
201                 return err;
202 
203         if (buf[PCF8563_REG_SC] & PCF8563_SC_LV) {
204                 pcf8563->voltage_low = 1;
205                 dev_info(&client->dev,
206                         "low voltage detected, date/time is not reliable.\n");
207         }
208 
209         dev_dbg(&client->dev,
210                 "%s: raw data is st1=%02x, st2=%02x, sec=%02x, min=%02x, hr=%02x, "
211                 "mday=%02x, wday=%02x, mon=%02x, year=%02x\n",
212                 __func__,
213                 buf[0], buf[1], buf[2], buf[3],
214                 buf[4], buf[5], buf[6], buf[7],
215                 buf[8]);
216 
217 
218         tm->tm_sec = bcd2bin(buf[PCF8563_REG_SC] & 0x7F);
219         tm->tm_min = bcd2bin(buf[PCF8563_REG_MN] & 0x7F);
220         tm->tm_hour = bcd2bin(buf[PCF8563_REG_HR] & 0x3F); /* rtc hr 0-23 */
221         tm->tm_mday = bcd2bin(buf[PCF8563_REG_DM] & 0x3F);
222         tm->tm_wday = buf[PCF8563_REG_DW] & 0x07;
223         tm->tm_mon = bcd2bin(buf[PCF8563_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */
224         tm->tm_year = bcd2bin(buf[PCF8563_REG_YR]);
225         if (tm->tm_year < 70)
226                 tm->tm_year += 100;     /* assume we are in 1970...2069 */
227         /* detect the polarity heuristically. see note above. */
228         pcf8563->c_polarity = (buf[PCF8563_REG_MO] & PCF8563_MO_C) ?
229                 (tm->tm_year >= 100) : (tm->tm_year < 100);
230 
231         dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
232                 "mday=%d, mon=%d, year=%d, wday=%d\n",
233                 __func__,
234                 tm->tm_sec, tm->tm_min, tm->tm_hour,
235                 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
236 
237         /* the clock can give out invalid datetime, but we cannot return
238          * -EINVAL otherwise hwclock will refuse to set the time on bootup.
239          */
240         if (rtc_valid_tm(tm) < 0)
241                 dev_err(&client->dev, "retrieved date/time is not valid.\n");
242 
243         return 0;
244 }
245 
246 static int pcf8563_set_datetime(struct i2c_client *client, struct rtc_time *tm)
247 {
248         struct pcf8563 *pcf8563 = i2c_get_clientdata(client);
249         int err;
250         unsigned char buf[9];
251 
252         dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, "
253                 "mday=%d, mon=%d, year=%d, wday=%d\n",
254                 __func__,
255                 tm->tm_sec, tm->tm_min, tm->tm_hour,
256                 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
257 
258         /* hours, minutes and seconds */
259         buf[PCF8563_REG_SC] = bin2bcd(tm->tm_sec);
260         buf[PCF8563_REG_MN] = bin2bcd(tm->tm_min);
261         buf[PCF8563_REG_HR] = bin2bcd(tm->tm_hour);
262 
263         buf[PCF8563_REG_DM] = bin2bcd(tm->tm_mday);
264 
265         /* month, 1 - 12 */
266         buf[PCF8563_REG_MO] = bin2bcd(tm->tm_mon + 1);
267 
268         /* year and century */
269         buf[PCF8563_REG_YR] = bin2bcd(tm->tm_year % 100);
270         if (pcf8563->c_polarity ? (tm->tm_year >= 100) : (tm->tm_year < 100))
271                 buf[PCF8563_REG_MO] |= PCF8563_MO_C;
272 
273         buf[PCF8563_REG_DW] = tm->tm_wday & 0x07;
274 
275         err = pcf8563_write_block_data(client, PCF8563_REG_SC,
276                                 9 - PCF8563_REG_SC, buf + PCF8563_REG_SC);
277         if (err)
278                 return err;
279 
280         return 0;
281 }
282 
283 #ifdef CONFIG_RTC_INTF_DEV
284 static int pcf8563_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
285 {
286         struct pcf8563 *pcf8563 = i2c_get_clientdata(to_i2c_client(dev));
287         struct rtc_time tm;
288 
289         switch (cmd) {
290         case RTC_VL_READ:
291                 if (pcf8563->voltage_low)
292                         dev_info(dev, "low voltage detected, date/time is not reliable.\n");
293 
294                 if (copy_to_user((void __user *)arg, &pcf8563->voltage_low,
295                                         sizeof(int)))
296                         return -EFAULT;
297                 return 0;
298         case RTC_VL_CLR:
299                 /*
300                  * Clear the VL bit in the seconds register in case
301                  * the time has not been set already (which would
302                  * have cleared it). This does not really matter
303                  * because of the cached voltage_low value but do it
304                  * anyway for consistency.
305                  */
306                 if (pcf8563_get_datetime(to_i2c_client(dev), &tm))
307                         pcf8563_set_datetime(to_i2c_client(dev), &tm);
308 
309                 /* Clear the cached value. */
310                 pcf8563->voltage_low = 0;
311 
312                 return 0;
313         default:
314                 return -ENOIOCTLCMD;
315         }
316 }
317 #else
318 #define pcf8563_rtc_ioctl NULL
319 #endif
320 
321 static int pcf8563_rtc_read_time(struct device *dev, struct rtc_time *tm)
322 {
323         return pcf8563_get_datetime(to_i2c_client(dev), tm);
324 }
325 
326 static int pcf8563_rtc_set_time(struct device *dev, struct rtc_time *tm)
327 {
328         return pcf8563_set_datetime(to_i2c_client(dev), tm);
329 }
330 
331 static int pcf8563_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *tm)
332 {
333         struct i2c_client *client = to_i2c_client(dev);
334         unsigned char buf[4];
335         int err;
336 
337         err = pcf8563_read_block_data(client, PCF8563_REG_AMN, 4, buf);
338         if (err)
339                 return err;
340 
341         dev_dbg(&client->dev,
342                 "%s: raw data is min=%02x, hr=%02x, mday=%02x, wday=%02x\n",
343                 __func__, buf[0], buf[1], buf[2], buf[3]);
344 
345         tm->time.tm_min = bcd2bin(buf[0] & 0x7F);
346         tm->time.tm_hour = bcd2bin(buf[1] & 0x3F);
347         tm->time.tm_mday = bcd2bin(buf[2] & 0x3F);
348         tm->time.tm_wday = bcd2bin(buf[3] & 0x7);
349         tm->time.tm_mon = -1;
350         tm->time.tm_year = -1;
351         tm->time.tm_yday = -1;
352         tm->time.tm_isdst = -1;
353 
354         err = pcf8563_get_alarm_mode(client, &tm->enabled, &tm->pending);
355         if (err < 0)
356                 return err;
357 
358         dev_dbg(&client->dev, "%s: tm is mins=%d, hours=%d, mday=%d, wday=%d,"
359                 " enabled=%d, pending=%d\n", __func__, tm->time.tm_min,
360                 tm->time.tm_hour, tm->time.tm_mday, tm->time.tm_wday,
361                 tm->enabled, tm->pending);
362 
363         return 0;
364 }
365 
366 static int pcf8563_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *tm)
367 {
368         struct i2c_client *client = to_i2c_client(dev);
369         unsigned char buf[4];
370         int err;
371         unsigned long alarm_time;
372 
373         /* The alarm has no seconds, round up to nearest minute */
374         if (tm->time.tm_sec) {
375                 rtc_tm_to_time(&tm->time, &alarm_time);
376                 alarm_time += 60-tm->time.tm_sec;
377                 rtc_time_to_tm(alarm_time, &tm->time);
378         }
379 
380         dev_dbg(dev, "%s, min=%d hour=%d wday=%d mday=%d "
381                 "enabled=%d pending=%d\n", __func__,
382                 tm->time.tm_min, tm->time.tm_hour, tm->time.tm_wday,
383                 tm->time.tm_mday, tm->enabled, tm->pending);
384 
385         buf[0] = bin2bcd(tm->time.tm_min);
386         buf[1] = bin2bcd(tm->time.tm_hour);
387         buf[2] = bin2bcd(tm->time.tm_mday);
388         buf[3] = tm->time.tm_wday & 0x07;
389 
390         err = pcf8563_write_block_data(client, PCF8563_REG_AMN, 4, buf);
391         if (err)
392                 return err;
393 
394         return pcf8563_set_alarm_mode(client, 1);
395 }
396 
397 static int pcf8563_irq_enable(struct device *dev, unsigned int enabled)
398 {
399         dev_dbg(dev, "%s: en=%d\n", __func__, enabled);
400         return pcf8563_set_alarm_mode(to_i2c_client(dev), !!enabled);
401 }
402 
403 static const struct rtc_class_ops pcf8563_rtc_ops = {
404         .ioctl          = pcf8563_rtc_ioctl,
405         .read_time      = pcf8563_rtc_read_time,
406         .set_time       = pcf8563_rtc_set_time,
407         .read_alarm     = pcf8563_rtc_read_alarm,
408         .set_alarm      = pcf8563_rtc_set_alarm,
409         .alarm_irq_enable = pcf8563_irq_enable,
410 };
411 
412 static int pcf8563_probe(struct i2c_client *client,
413                                 const struct i2c_device_id *id)
414 {
415         struct pcf8563 *pcf8563;
416         int err;
417         unsigned char buf;
418         unsigned char alm_pending;
419 
420         dev_dbg(&client->dev, "%s\n", __func__);
421 
422         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
423                 return -ENODEV;
424 
425         pcf8563 = devm_kzalloc(&client->dev, sizeof(struct pcf8563),
426                                 GFP_KERNEL);
427         if (!pcf8563)
428                 return -ENOMEM;
429 
430         dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");
431 
432         i2c_set_clientdata(client, pcf8563);
433         pcf8563->client = client;
434         device_set_wakeup_capable(&client->dev, 1);
435 
436         /* Set timer to lowest frequency to save power (ref Haoyu datasheet) */
437         buf = PCF8563_TMRC_1_60;
438         err = pcf8563_write_block_data(client, PCF8563_REG_TMRC, 1, &buf);
439         if (err < 0) {
440                 dev_err(&client->dev, "%s: write error\n", __func__);
441                 return err;
442         }
443 
444         err = pcf8563_get_alarm_mode(client, NULL, &alm_pending);
445         if (err < 0) {
446                 dev_err(&client->dev, "%s: read error\n", __func__);
447                 return err;
448         }
449         if (alm_pending)
450                 pcf8563_set_alarm_mode(client, 0);
451 
452         pcf8563->rtc = devm_rtc_device_register(&client->dev,
453                                 pcf8563_driver.driver.name,
454                                 &pcf8563_rtc_ops, THIS_MODULE);
455 
456         if (IS_ERR(pcf8563->rtc))
457                 return PTR_ERR(pcf8563->rtc);
458 
459         if (client->irq > 0) {
460                 err = devm_request_threaded_irq(&client->dev, client->irq,
461                                 NULL, pcf8563_irq,
462                                 IRQF_SHARED|IRQF_ONESHOT|IRQF_TRIGGER_FALLING,
463                                 pcf8563->rtc->name, client);
464                 if (err) {
465                         dev_err(&client->dev, "unable to request IRQ %d\n",
466                                                                 client->irq);
467                         return err;
468                 }
469 
470         }
471 
472         /* the pcf8563 alarm only supports a minute accuracy */
473         pcf8563->rtc->uie_unsupported = 1;
474 
475         return 0;
476 }
477 
478 static const struct i2c_device_id pcf8563_id[] = {
479         { "pcf8563", 0 },
480         { "rtc8564", 0 },
481         { }
482 };
483 MODULE_DEVICE_TABLE(i2c, pcf8563_id);
484 
485 #ifdef CONFIG_OF
486 static const struct of_device_id pcf8563_of_match[] = {
487         { .compatible = "nxp,pcf8563" },
488         {}
489 };
490 MODULE_DEVICE_TABLE(of, pcf8563_of_match);
491 #endif
492 
493 static struct i2c_driver pcf8563_driver = {
494         .driver         = {
495                 .name   = "rtc-pcf8563",
496                 .owner  = THIS_MODULE,
497                 .of_match_table = of_match_ptr(pcf8563_of_match),
498         },
499         .probe          = pcf8563_probe,
500         .id_table       = pcf8563_id,
501 };
502 
503 module_i2c_driver(pcf8563_driver);
504 
505 MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
506 MODULE_DESCRIPTION("Philips PCF8563/Epson RTC8564 RTC driver");
507 MODULE_LICENSE("GPL");
508 MODULE_VERSION(DRV_VERSION);
509 

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