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

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