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Linux/drivers/rtc/rtc-ds1307.c

  1 /*
  2  * rtc-ds1307.c - RTC driver for some mostly-compatible I2C chips.
  3  *
  4  *  Copyright (C) 2005 James Chapman (ds1337 core)
  5  *  Copyright (C) 2006 David Brownell
  6  *  Copyright (C) 2009 Matthias Fuchs (rx8025 support)
  7  *  Copyright (C) 2012 Bertrand Achard (nvram access fixes)
  8  *
  9  * This program is free software; you can redistribute it and/or modify
 10  * it under the terms of the GNU General Public License version 2 as
 11  * published by the Free Software Foundation.
 12  */
 13 
 14 #include <linux/module.h>
 15 #include <linux/init.h>
 16 #include <linux/slab.h>
 17 #include <linux/i2c.h>
 18 #include <linux/string.h>
 19 #include <linux/rtc.h>
 20 #include <linux/bcd.h>
 21 #include <linux/rtc/ds1307.h>
 22 
 23 /*
 24  * We can't determine type by probing, but if we expect pre-Linux code
 25  * to have set the chip up as a clock (turning on the oscillator and
 26  * setting the date and time), Linux can ignore the non-clock features.
 27  * That's a natural job for a factory or repair bench.
 28  */
 29 enum ds_type {
 30         ds_1307,
 31         ds_1337,
 32         ds_1338,
 33         ds_1339,
 34         ds_1340,
 35         ds_1388,
 36         ds_3231,
 37         m41t00,
 38         mcp7941x,
 39         rx_8025,
 40         last_ds_type /* always last */
 41         /* rs5c372 too?  different address... */
 42 };
 43 
 44 
 45 /* RTC registers don't differ much, except for the century flag */
 46 #define DS1307_REG_SECS         0x00    /* 00-59 */
 47 #       define DS1307_BIT_CH            0x80
 48 #       define DS1340_BIT_nEOSC         0x80
 49 #       define MCP7941X_BIT_ST          0x80
 50 #define DS1307_REG_MIN          0x01    /* 00-59 */
 51 #define DS1307_REG_HOUR         0x02    /* 00-23, or 1-12{am,pm} */
 52 #       define DS1307_BIT_12HR          0x40    /* in REG_HOUR */
 53 #       define DS1307_BIT_PM            0x20    /* in REG_HOUR */
 54 #       define DS1340_BIT_CENTURY_EN    0x80    /* in REG_HOUR */
 55 #       define DS1340_BIT_CENTURY       0x40    /* in REG_HOUR */
 56 #define DS1307_REG_WDAY         0x03    /* 01-07 */
 57 #       define MCP7941X_BIT_VBATEN      0x08
 58 #define DS1307_REG_MDAY         0x04    /* 01-31 */
 59 #define DS1307_REG_MONTH        0x05    /* 01-12 */
 60 #       define DS1337_BIT_CENTURY       0x80    /* in REG_MONTH */
 61 #define DS1307_REG_YEAR         0x06    /* 00-99 */
 62 
 63 /*
 64  * Other registers (control, status, alarms, trickle charge, NVRAM, etc)
 65  * start at 7, and they differ a LOT. Only control and status matter for
 66  * basic RTC date and time functionality; be careful using them.
 67  */
 68 #define DS1307_REG_CONTROL      0x07            /* or ds1338 */
 69 #       define DS1307_BIT_OUT           0x80
 70 #       define DS1338_BIT_OSF           0x20
 71 #       define DS1307_BIT_SQWE          0x10
 72 #       define DS1307_BIT_RS1           0x02
 73 #       define DS1307_BIT_RS0           0x01
 74 #define DS1337_REG_CONTROL      0x0e
 75 #       define DS1337_BIT_nEOSC         0x80
 76 #       define DS1339_BIT_BBSQI         0x20
 77 #       define DS3231_BIT_BBSQW         0x40 /* same as BBSQI */
 78 #       define DS1337_BIT_RS2           0x10
 79 #       define DS1337_BIT_RS1           0x08
 80 #       define DS1337_BIT_INTCN         0x04
 81 #       define DS1337_BIT_A2IE          0x02
 82 #       define DS1337_BIT_A1IE          0x01
 83 #define DS1340_REG_CONTROL      0x07
 84 #       define DS1340_BIT_OUT           0x80
 85 #       define DS1340_BIT_FT            0x40
 86 #       define DS1340_BIT_CALIB_SIGN    0x20
 87 #       define DS1340_M_CALIBRATION     0x1f
 88 #define DS1340_REG_FLAG         0x09
 89 #       define DS1340_BIT_OSF           0x80
 90 #define DS1337_REG_STATUS       0x0f
 91 #       define DS1337_BIT_OSF           0x80
 92 #       define DS1337_BIT_A2I           0x02
 93 #       define DS1337_BIT_A1I           0x01
 94 #define DS1339_REG_ALARM1_SECS  0x07
 95 
 96 #define DS13XX_TRICKLE_CHARGER_MAGIC    0xa0
 97 
 98 #define RX8025_REG_CTRL1        0x0e
 99 #       define RX8025_BIT_2412          0x20
100 #define RX8025_REG_CTRL2        0x0f
101 #       define RX8025_BIT_PON           0x10
102 #       define RX8025_BIT_VDET          0x40
103 #       define RX8025_BIT_XST           0x20
104 
105 
106 struct ds1307 {
107         u8                      offset; /* register's offset */
108         u8                      regs[11];
109         u16                     nvram_offset;
110         struct bin_attribute    *nvram;
111         enum ds_type            type;
112         unsigned long           flags;
113 #define HAS_NVRAM       0               /* bit 0 == sysfs file active */
114 #define HAS_ALARM       1               /* bit 1 == irq claimed */
115         struct i2c_client       *client;
116         struct rtc_device       *rtc;
117         struct work_struct      work;
118         s32 (*read_block_data)(const struct i2c_client *client, u8 command,
119                                u8 length, u8 *values);
120         s32 (*write_block_data)(const struct i2c_client *client, u8 command,
121                                 u8 length, const u8 *values);
122 };
123 
124 struct chip_desc {
125         unsigned                alarm:1;
126         u16                     nvram_offset;
127         u16                     nvram_size;
128         u16                     trickle_charger_reg;
129 };
130 
131 static const struct chip_desc chips[last_ds_type] = {
132         [ds_1307] = {
133                 .nvram_offset   = 8,
134                 .nvram_size     = 56,
135         },
136         [ds_1337] = {
137                 .alarm          = 1,
138         },
139         [ds_1338] = {
140                 .nvram_offset   = 8,
141                 .nvram_size     = 56,
142         },
143         [ds_1339] = {
144                 .alarm          = 1,
145                 .trickle_charger_reg = 0x10,
146         },
147         [ds_1340] = {
148                 .trickle_charger_reg = 0x08,
149         },
150         [ds_1388] = {
151                 .trickle_charger_reg = 0x0a,
152         },
153         [ds_3231] = {
154                 .alarm          = 1,
155         },
156         [mcp7941x] = {
157                 .alarm          = 1,
158                 /* this is battery backed SRAM */
159                 .nvram_offset   = 0x20,
160                 .nvram_size     = 0x40,
161         },
162 };
163 
164 static const struct i2c_device_id ds1307_id[] = {
165         { "ds1307", ds_1307 },
166         { "ds1337", ds_1337 },
167         { "ds1338", ds_1338 },
168         { "ds1339", ds_1339 },
169         { "ds1388", ds_1388 },
170         { "ds1340", ds_1340 },
171         { "ds3231", ds_3231 },
172         { "m41t00", m41t00 },
173         { "mcp7941x", mcp7941x },
174         { "pt7c4338", ds_1307 },
175         { "rx8025", rx_8025 },
176         { }
177 };
178 MODULE_DEVICE_TABLE(i2c, ds1307_id);
179 
180 /*----------------------------------------------------------------------*/
181 
182 #define BLOCK_DATA_MAX_TRIES 10
183 
184 static s32 ds1307_read_block_data_once(const struct i2c_client *client,
185                                        u8 command, u8 length, u8 *values)
186 {
187         s32 i, data;
188 
189         for (i = 0; i < length; i++) {
190                 data = i2c_smbus_read_byte_data(client, command + i);
191                 if (data < 0)
192                         return data;
193                 values[i] = data;
194         }
195         return i;
196 }
197 
198 static s32 ds1307_read_block_data(const struct i2c_client *client, u8 command,
199                                   u8 length, u8 *values)
200 {
201         u8 oldvalues[255];
202         s32 ret;
203         int tries = 0;
204 
205         dev_dbg(&client->dev, "ds1307_read_block_data (length=%d)\n", length);
206         ret = ds1307_read_block_data_once(client, command, length, values);
207         if (ret < 0)
208                 return ret;
209         do {
210                 if (++tries > BLOCK_DATA_MAX_TRIES) {
211                         dev_err(&client->dev,
212                                 "ds1307_read_block_data failed\n");
213                         return -EIO;
214                 }
215                 memcpy(oldvalues, values, length);
216                 ret = ds1307_read_block_data_once(client, command, length,
217                                                   values);
218                 if (ret < 0)
219                         return ret;
220         } while (memcmp(oldvalues, values, length));
221         return length;
222 }
223 
224 static s32 ds1307_write_block_data(const struct i2c_client *client, u8 command,
225                                    u8 length, const u8 *values)
226 {
227         u8 currvalues[255];
228         int tries = 0;
229 
230         dev_dbg(&client->dev, "ds1307_write_block_data (length=%d)\n", length);
231         do {
232                 s32 i, ret;
233 
234                 if (++tries > BLOCK_DATA_MAX_TRIES) {
235                         dev_err(&client->dev,
236                                 "ds1307_write_block_data failed\n");
237                         return -EIO;
238                 }
239                 for (i = 0; i < length; i++) {
240                         ret = i2c_smbus_write_byte_data(client, command + i,
241                                                         values[i]);
242                         if (ret < 0)
243                                 return ret;
244                 }
245                 ret = ds1307_read_block_data_once(client, command, length,
246                                                   currvalues);
247                 if (ret < 0)
248                         return ret;
249         } while (memcmp(currvalues, values, length));
250         return length;
251 }
252 
253 /*----------------------------------------------------------------------*/
254 
255 /* These RTC devices are not designed to be connected to a SMbus adapter.
256    SMbus limits block operations length to 32 bytes, whereas it's not
257    limited on I2C buses. As a result, accesses may exceed 32 bytes;
258    in that case, split them into smaller blocks */
259 
260 static s32 ds1307_native_smbus_write_block_data(const struct i2c_client *client,
261                                 u8 command, u8 length, const u8 *values)
262 {
263         u8 suboffset = 0;
264 
265         if (length <= I2C_SMBUS_BLOCK_MAX)
266                 return i2c_smbus_write_i2c_block_data(client,
267                                         command, length, values);
268 
269         while (suboffset < length) {
270                 s32 retval = i2c_smbus_write_i2c_block_data(client,
271                                 command + suboffset,
272                                 min(I2C_SMBUS_BLOCK_MAX, length - suboffset),
273                                 values + suboffset);
274                 if (retval < 0)
275                         return retval;
276 
277                 suboffset += I2C_SMBUS_BLOCK_MAX;
278         }
279         return length;
280 }
281 
282 static s32 ds1307_native_smbus_read_block_data(const struct i2c_client *client,
283                                 u8 command, u8 length, u8 *values)
284 {
285         u8 suboffset = 0;
286 
287         if (length <= I2C_SMBUS_BLOCK_MAX)
288                 return i2c_smbus_read_i2c_block_data(client,
289                                         command, length, values);
290 
291         while (suboffset < length) {
292                 s32 retval = i2c_smbus_read_i2c_block_data(client,
293                                 command + suboffset,
294                                 min(I2C_SMBUS_BLOCK_MAX, length - suboffset),
295                                 values + suboffset);
296                 if (retval < 0)
297                         return retval;
298 
299                 suboffset += I2C_SMBUS_BLOCK_MAX;
300         }
301         return length;
302 }
303 
304 /*----------------------------------------------------------------------*/
305 
306 /*
307  * The IRQ logic includes a "real" handler running in IRQ context just
308  * long enough to schedule this workqueue entry.   We need a task context
309  * to talk to the RTC, since I2C I/O calls require that; and disable the
310  * IRQ until we clear its status on the chip, so that this handler can
311  * work with any type of triggering (not just falling edge).
312  *
313  * The ds1337 and ds1339 both have two alarms, but we only use the first
314  * one (with a "seconds" field).  For ds1337 we expect nINTA is our alarm
315  * signal; ds1339 chips have only one alarm signal.
316  */
317 static void ds1307_work(struct work_struct *work)
318 {
319         struct ds1307           *ds1307;
320         struct i2c_client       *client;
321         struct mutex            *lock;
322         int                     stat, control;
323 
324         ds1307 = container_of(work, struct ds1307, work);
325         client = ds1307->client;
326         lock = &ds1307->rtc->ops_lock;
327 
328         mutex_lock(lock);
329         stat = i2c_smbus_read_byte_data(client, DS1337_REG_STATUS);
330         if (stat < 0)
331                 goto out;
332 
333         if (stat & DS1337_BIT_A1I) {
334                 stat &= ~DS1337_BIT_A1I;
335                 i2c_smbus_write_byte_data(client, DS1337_REG_STATUS, stat);
336 
337                 control = i2c_smbus_read_byte_data(client, DS1337_REG_CONTROL);
338                 if (control < 0)
339                         goto out;
340 
341                 control &= ~DS1337_BIT_A1IE;
342                 i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL, control);
343 
344                 rtc_update_irq(ds1307->rtc, 1, RTC_AF | RTC_IRQF);
345         }
346 
347 out:
348         if (test_bit(HAS_ALARM, &ds1307->flags))
349                 enable_irq(client->irq);
350         mutex_unlock(lock);
351 }
352 
353 static irqreturn_t ds1307_irq(int irq, void *dev_id)
354 {
355         struct i2c_client       *client = dev_id;
356         struct ds1307           *ds1307 = i2c_get_clientdata(client);
357 
358         disable_irq_nosync(irq);
359         schedule_work(&ds1307->work);
360         return IRQ_HANDLED;
361 }
362 
363 /*----------------------------------------------------------------------*/
364 
365 static int ds1307_get_time(struct device *dev, struct rtc_time *t)
366 {
367         struct ds1307   *ds1307 = dev_get_drvdata(dev);
368         int             tmp;
369 
370         /* read the RTC date and time registers all at once */
371         tmp = ds1307->read_block_data(ds1307->client,
372                 ds1307->offset, 7, ds1307->regs);
373         if (tmp != 7) {
374                 dev_err(dev, "%s error %d\n", "read", tmp);
375                 return -EIO;
376         }
377 
378         dev_dbg(dev, "%s: %7ph\n", "read", ds1307->regs);
379 
380         t->tm_sec = bcd2bin(ds1307->regs[DS1307_REG_SECS] & 0x7f);
381         t->tm_min = bcd2bin(ds1307->regs[DS1307_REG_MIN] & 0x7f);
382         tmp = ds1307->regs[DS1307_REG_HOUR] & 0x3f;
383         t->tm_hour = bcd2bin(tmp);
384         t->tm_wday = bcd2bin(ds1307->regs[DS1307_REG_WDAY] & 0x07) - 1;
385         t->tm_mday = bcd2bin(ds1307->regs[DS1307_REG_MDAY] & 0x3f);
386         tmp = ds1307->regs[DS1307_REG_MONTH] & 0x1f;
387         t->tm_mon = bcd2bin(tmp) - 1;
388 
389         /* assume 20YY not 19YY, and ignore DS1337_BIT_CENTURY */
390         t->tm_year = bcd2bin(ds1307->regs[DS1307_REG_YEAR]) + 100;
391 
392         dev_dbg(dev, "%s secs=%d, mins=%d, "
393                 "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
394                 "read", t->tm_sec, t->tm_min,
395                 t->tm_hour, t->tm_mday,
396                 t->tm_mon, t->tm_year, t->tm_wday);
397 
398         /* initial clock setting can be undefined */
399         return rtc_valid_tm(t);
400 }
401 
402 static int ds1307_set_time(struct device *dev, struct rtc_time *t)
403 {
404         struct ds1307   *ds1307 = dev_get_drvdata(dev);
405         int             result;
406         int             tmp;
407         u8              *buf = ds1307->regs;
408 
409         dev_dbg(dev, "%s secs=%d, mins=%d, "
410                 "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
411                 "write", t->tm_sec, t->tm_min,
412                 t->tm_hour, t->tm_mday,
413                 t->tm_mon, t->tm_year, t->tm_wday);
414 
415         buf[DS1307_REG_SECS] = bin2bcd(t->tm_sec);
416         buf[DS1307_REG_MIN] = bin2bcd(t->tm_min);
417         buf[DS1307_REG_HOUR] = bin2bcd(t->tm_hour);
418         buf[DS1307_REG_WDAY] = bin2bcd(t->tm_wday + 1);
419         buf[DS1307_REG_MDAY] = bin2bcd(t->tm_mday);
420         buf[DS1307_REG_MONTH] = bin2bcd(t->tm_mon + 1);
421 
422         /* assume 20YY not 19YY */
423         tmp = t->tm_year - 100;
424         buf[DS1307_REG_YEAR] = bin2bcd(tmp);
425 
426         switch (ds1307->type) {
427         case ds_1337:
428         case ds_1339:
429         case ds_3231:
430                 buf[DS1307_REG_MONTH] |= DS1337_BIT_CENTURY;
431                 break;
432         case ds_1340:
433                 buf[DS1307_REG_HOUR] |= DS1340_BIT_CENTURY_EN
434                                 | DS1340_BIT_CENTURY;
435                 break;
436         case mcp7941x:
437                 /*
438                  * these bits were cleared when preparing the date/time
439                  * values and need to be set again before writing the
440                  * buffer out to the device.
441                  */
442                 buf[DS1307_REG_SECS] |= MCP7941X_BIT_ST;
443                 buf[DS1307_REG_WDAY] |= MCP7941X_BIT_VBATEN;
444                 break;
445         default:
446                 break;
447         }
448 
449         dev_dbg(dev, "%s: %7ph\n", "write", buf);
450 
451         result = ds1307->write_block_data(ds1307->client,
452                 ds1307->offset, 7, buf);
453         if (result < 0) {
454                 dev_err(dev, "%s error %d\n", "write", result);
455                 return result;
456         }
457         return 0;
458 }
459 
460 static int ds1337_read_alarm(struct device *dev, struct rtc_wkalrm *t)
461 {
462         struct i2c_client       *client = to_i2c_client(dev);
463         struct ds1307           *ds1307 = i2c_get_clientdata(client);
464         int                     ret;
465 
466         if (!test_bit(HAS_ALARM, &ds1307->flags))
467                 return -EINVAL;
468 
469         /* read all ALARM1, ALARM2, and status registers at once */
470         ret = ds1307->read_block_data(client,
471                         DS1339_REG_ALARM1_SECS, 9, ds1307->regs);
472         if (ret != 9) {
473                 dev_err(dev, "%s error %d\n", "alarm read", ret);
474                 return -EIO;
475         }
476 
477         dev_dbg(dev, "%s: %02x %02x %02x %02x, %02x %02x %02x, %02x %02x\n",
478                         "alarm read",
479                         ds1307->regs[0], ds1307->regs[1],
480                         ds1307->regs[2], ds1307->regs[3],
481                         ds1307->regs[4], ds1307->regs[5],
482                         ds1307->regs[6], ds1307->regs[7],
483                         ds1307->regs[8]);
484 
485         /*
486          * report alarm time (ALARM1); assume 24 hour and day-of-month modes,
487          * and that all four fields are checked matches
488          */
489         t->time.tm_sec = bcd2bin(ds1307->regs[0] & 0x7f);
490         t->time.tm_min = bcd2bin(ds1307->regs[1] & 0x7f);
491         t->time.tm_hour = bcd2bin(ds1307->regs[2] & 0x3f);
492         t->time.tm_mday = bcd2bin(ds1307->regs[3] & 0x3f);
493         t->time.tm_mon = -1;
494         t->time.tm_year = -1;
495         t->time.tm_wday = -1;
496         t->time.tm_yday = -1;
497         t->time.tm_isdst = -1;
498 
499         /* ... and status */
500         t->enabled = !!(ds1307->regs[7] & DS1337_BIT_A1IE);
501         t->pending = !!(ds1307->regs[8] & DS1337_BIT_A1I);
502 
503         dev_dbg(dev, "%s secs=%d, mins=%d, "
504                 "hours=%d, mday=%d, enabled=%d, pending=%d\n",
505                 "alarm read", t->time.tm_sec, t->time.tm_min,
506                 t->time.tm_hour, t->time.tm_mday,
507                 t->enabled, t->pending);
508 
509         return 0;
510 }
511 
512 static int ds1337_set_alarm(struct device *dev, struct rtc_wkalrm *t)
513 {
514         struct i2c_client       *client = to_i2c_client(dev);
515         struct ds1307           *ds1307 = i2c_get_clientdata(client);
516         unsigned char           *buf = ds1307->regs;
517         u8                      control, status;
518         int                     ret;
519 
520         if (!test_bit(HAS_ALARM, &ds1307->flags))
521                 return -EINVAL;
522 
523         dev_dbg(dev, "%s secs=%d, mins=%d, "
524                 "hours=%d, mday=%d, enabled=%d, pending=%d\n",
525                 "alarm set", t->time.tm_sec, t->time.tm_min,
526                 t->time.tm_hour, t->time.tm_mday,
527                 t->enabled, t->pending);
528 
529         /* read current status of both alarms and the chip */
530         ret = ds1307->read_block_data(client,
531                         DS1339_REG_ALARM1_SECS, 9, buf);
532         if (ret != 9) {
533                 dev_err(dev, "%s error %d\n", "alarm write", ret);
534                 return -EIO;
535         }
536         control = ds1307->regs[7];
537         status = ds1307->regs[8];
538 
539         dev_dbg(dev, "%s: %02x %02x %02x %02x, %02x %02x %02x, %02x %02x\n",
540                         "alarm set (old status)",
541                         ds1307->regs[0], ds1307->regs[1],
542                         ds1307->regs[2], ds1307->regs[3],
543                         ds1307->regs[4], ds1307->regs[5],
544                         ds1307->regs[6], control, status);
545 
546         /* set ALARM1, using 24 hour and day-of-month modes */
547         buf[0] = bin2bcd(t->time.tm_sec);
548         buf[1] = bin2bcd(t->time.tm_min);
549         buf[2] = bin2bcd(t->time.tm_hour);
550         buf[3] = bin2bcd(t->time.tm_mday);
551 
552         /* set ALARM2 to non-garbage */
553         buf[4] = 0;
554         buf[5] = 0;
555         buf[6] = 0;
556 
557         /* optionally enable ALARM1 */
558         buf[7] = control & ~(DS1337_BIT_A1IE | DS1337_BIT_A2IE);
559         if (t->enabled) {
560                 dev_dbg(dev, "alarm IRQ armed\n");
561                 buf[7] |= DS1337_BIT_A1IE;      /* only ALARM1 is used */
562         }
563         buf[8] = status & ~(DS1337_BIT_A1I | DS1337_BIT_A2I);
564 
565         ret = ds1307->write_block_data(client,
566                         DS1339_REG_ALARM1_SECS, 9, buf);
567         if (ret < 0) {
568                 dev_err(dev, "can't set alarm time\n");
569                 return ret;
570         }
571 
572         return 0;
573 }
574 
575 static int ds1307_alarm_irq_enable(struct device *dev, unsigned int enabled)
576 {
577         struct i2c_client       *client = to_i2c_client(dev);
578         struct ds1307           *ds1307 = i2c_get_clientdata(client);
579         int                     ret;
580 
581         if (!test_bit(HAS_ALARM, &ds1307->flags))
582                 return -ENOTTY;
583 
584         ret = i2c_smbus_read_byte_data(client, DS1337_REG_CONTROL);
585         if (ret < 0)
586                 return ret;
587 
588         if (enabled)
589                 ret |= DS1337_BIT_A1IE;
590         else
591                 ret &= ~DS1337_BIT_A1IE;
592 
593         ret = i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL, ret);
594         if (ret < 0)
595                 return ret;
596 
597         return 0;
598 }
599 
600 static const struct rtc_class_ops ds13xx_rtc_ops = {
601         .read_time      = ds1307_get_time,
602         .set_time       = ds1307_set_time,
603         .read_alarm     = ds1337_read_alarm,
604         .set_alarm      = ds1337_set_alarm,
605         .alarm_irq_enable = ds1307_alarm_irq_enable,
606 };
607 
608 /*----------------------------------------------------------------------*/
609 
610 /*
611  * Alarm support for mcp7941x devices.
612  */
613 
614 #define MCP7941X_REG_CONTROL            0x07
615 #       define MCP7941X_BIT_ALM0_EN     0x10
616 #       define MCP7941X_BIT_ALM1_EN     0x20
617 #define MCP7941X_REG_ALARM0_BASE        0x0a
618 #define MCP7941X_REG_ALARM0_CTRL        0x0d
619 #define MCP7941X_REG_ALARM1_BASE        0x11
620 #define MCP7941X_REG_ALARM1_CTRL        0x14
621 #       define MCP7941X_BIT_ALMX_IF     (1 << 3)
622 #       define MCP7941X_BIT_ALMX_C0     (1 << 4)
623 #       define MCP7941X_BIT_ALMX_C1     (1 << 5)
624 #       define MCP7941X_BIT_ALMX_C2     (1 << 6)
625 #       define MCP7941X_BIT_ALMX_POL    (1 << 7)
626 #       define MCP7941X_MSK_ALMX_MATCH  (MCP7941X_BIT_ALMX_C0 | \
627                                          MCP7941X_BIT_ALMX_C1 | \
628                                          MCP7941X_BIT_ALMX_C2)
629 
630 static void mcp7941x_work(struct work_struct *work)
631 {
632         struct ds1307 *ds1307 = container_of(work, struct ds1307, work);
633         struct i2c_client *client = ds1307->client;
634         int reg, ret;
635 
636         mutex_lock(&ds1307->rtc->ops_lock);
637 
638         /* Check and clear alarm 0 interrupt flag. */
639         reg = i2c_smbus_read_byte_data(client, MCP7941X_REG_ALARM0_CTRL);
640         if (reg < 0)
641                 goto out;
642         if (!(reg & MCP7941X_BIT_ALMX_IF))
643                 goto out;
644         reg &= ~MCP7941X_BIT_ALMX_IF;
645         ret = i2c_smbus_write_byte_data(client, MCP7941X_REG_ALARM0_CTRL, reg);
646         if (ret < 0)
647                 goto out;
648 
649         /* Disable alarm 0. */
650         reg = i2c_smbus_read_byte_data(client, MCP7941X_REG_CONTROL);
651         if (reg < 0)
652                 goto out;
653         reg &= ~MCP7941X_BIT_ALM0_EN;
654         ret = i2c_smbus_write_byte_data(client, MCP7941X_REG_CONTROL, reg);
655         if (ret < 0)
656                 goto out;
657 
658         rtc_update_irq(ds1307->rtc, 1, RTC_AF | RTC_IRQF);
659 
660 out:
661         if (test_bit(HAS_ALARM, &ds1307->flags))
662                 enable_irq(client->irq);
663         mutex_unlock(&ds1307->rtc->ops_lock);
664 }
665 
666 static int mcp7941x_read_alarm(struct device *dev, struct rtc_wkalrm *t)
667 {
668         struct i2c_client *client = to_i2c_client(dev);
669         struct ds1307 *ds1307 = i2c_get_clientdata(client);
670         u8 *regs = ds1307->regs;
671         int ret;
672 
673         if (!test_bit(HAS_ALARM, &ds1307->flags))
674                 return -EINVAL;
675 
676         /* Read control and alarm 0 registers. */
677         ret = ds1307->read_block_data(client, MCP7941X_REG_CONTROL, 10, regs);
678         if (ret < 0)
679                 return ret;
680 
681         t->enabled = !!(regs[0] & MCP7941X_BIT_ALM0_EN);
682 
683         /* Report alarm 0 time assuming 24-hour and day-of-month modes. */
684         t->time.tm_sec = bcd2bin(ds1307->regs[3] & 0x7f);
685         t->time.tm_min = bcd2bin(ds1307->regs[4] & 0x7f);
686         t->time.tm_hour = bcd2bin(ds1307->regs[5] & 0x3f);
687         t->time.tm_wday = bcd2bin(ds1307->regs[6] & 0x7) - 1;
688         t->time.tm_mday = bcd2bin(ds1307->regs[7] & 0x3f);
689         t->time.tm_mon = bcd2bin(ds1307->regs[8] & 0x1f) - 1;
690         t->time.tm_year = -1;
691         t->time.tm_yday = -1;
692         t->time.tm_isdst = -1;
693 
694         dev_dbg(dev, "%s, sec=%d min=%d hour=%d wday=%d mday=%d mon=%d "
695                 "enabled=%d polarity=%d irq=%d match=%d\n", __func__,
696                 t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
697                 t->time.tm_wday, t->time.tm_mday, t->time.tm_mon, t->enabled,
698                 !!(ds1307->regs[6] & MCP7941X_BIT_ALMX_POL),
699                 !!(ds1307->regs[6] & MCP7941X_BIT_ALMX_IF),
700                 (ds1307->regs[6] & MCP7941X_MSK_ALMX_MATCH) >> 4);
701 
702         return 0;
703 }
704 
705 static int mcp7941x_set_alarm(struct device *dev, struct rtc_wkalrm *t)
706 {
707         struct i2c_client *client = to_i2c_client(dev);
708         struct ds1307 *ds1307 = i2c_get_clientdata(client);
709         unsigned char *regs = ds1307->regs;
710         int ret;
711 
712         if (!test_bit(HAS_ALARM, &ds1307->flags))
713                 return -EINVAL;
714 
715         dev_dbg(dev, "%s, sec=%d min=%d hour=%d wday=%d mday=%d mon=%d "
716                 "enabled=%d pending=%d\n", __func__,
717                 t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
718                 t->time.tm_wday, t->time.tm_mday, t->time.tm_mon,
719                 t->enabled, t->pending);
720 
721         /* Read control and alarm 0 registers. */
722         ret = ds1307->read_block_data(client, MCP7941X_REG_CONTROL, 10, regs);
723         if (ret < 0)
724                 return ret;
725 
726         /* Set alarm 0, using 24-hour and day-of-month modes. */
727         regs[3] = bin2bcd(t->time.tm_sec);
728         regs[4] = bin2bcd(t->time.tm_min);
729         regs[5] = bin2bcd(t->time.tm_hour);
730         regs[6] = bin2bcd(t->time.tm_wday) + 1;
731         regs[7] = bin2bcd(t->time.tm_mday);
732         regs[8] = bin2bcd(t->time.tm_mon) + 1;
733 
734         /* Clear the alarm 0 interrupt flag. */
735         regs[6] &= ~MCP7941X_BIT_ALMX_IF;
736         /* Set alarm match: second, minute, hour, day, date, month. */
737         regs[6] |= MCP7941X_MSK_ALMX_MATCH;
738 
739         if (t->enabled)
740                 regs[0] |= MCP7941X_BIT_ALM0_EN;
741         else
742                 regs[0] &= ~MCP7941X_BIT_ALM0_EN;
743 
744         ret = ds1307->write_block_data(client, MCP7941X_REG_CONTROL, 10, regs);
745         if (ret < 0)
746                 return ret;
747 
748         return 0;
749 }
750 
751 static int mcp7941x_alarm_irq_enable(struct device *dev, unsigned int enabled)
752 {
753         struct i2c_client *client = to_i2c_client(dev);
754         struct ds1307 *ds1307 = i2c_get_clientdata(client);
755         int reg;
756 
757         if (!test_bit(HAS_ALARM, &ds1307->flags))
758                 return -EINVAL;
759 
760         reg = i2c_smbus_read_byte_data(client, MCP7941X_REG_CONTROL);
761         if (reg < 0)
762                 return reg;
763 
764         if (enabled)
765                 reg |= MCP7941X_BIT_ALM0_EN;
766         else
767                 reg &= ~MCP7941X_BIT_ALM0_EN;
768 
769         return i2c_smbus_write_byte_data(client, MCP7941X_REG_CONTROL, reg);
770 }
771 
772 static const struct rtc_class_ops mcp7941x_rtc_ops = {
773         .read_time      = ds1307_get_time,
774         .set_time       = ds1307_set_time,
775         .read_alarm     = mcp7941x_read_alarm,
776         .set_alarm      = mcp7941x_set_alarm,
777         .alarm_irq_enable = mcp7941x_alarm_irq_enable,
778 };
779 
780 /*----------------------------------------------------------------------*/
781 
782 static ssize_t
783 ds1307_nvram_read(struct file *filp, struct kobject *kobj,
784                 struct bin_attribute *attr,
785                 char *buf, loff_t off, size_t count)
786 {
787         struct i2c_client       *client;
788         struct ds1307           *ds1307;
789         int                     result;
790 
791         client = kobj_to_i2c_client(kobj);
792         ds1307 = i2c_get_clientdata(client);
793 
794         if (unlikely(off >= ds1307->nvram->size))
795                 return 0;
796         if ((off + count) > ds1307->nvram->size)
797                 count = ds1307->nvram->size - off;
798         if (unlikely(!count))
799                 return count;
800 
801         result = ds1307->read_block_data(client, ds1307->nvram_offset + off,
802                                                                 count, buf);
803         if (result < 0)
804                 dev_err(&client->dev, "%s error %d\n", "nvram read", result);
805         return result;
806 }
807 
808 static ssize_t
809 ds1307_nvram_write(struct file *filp, struct kobject *kobj,
810                 struct bin_attribute *attr,
811                 char *buf, loff_t off, size_t count)
812 {
813         struct i2c_client       *client;
814         struct ds1307           *ds1307;
815         int                     result;
816 
817         client = kobj_to_i2c_client(kobj);
818         ds1307 = i2c_get_clientdata(client);
819 
820         if (unlikely(off >= ds1307->nvram->size))
821                 return -EFBIG;
822         if ((off + count) > ds1307->nvram->size)
823                 count = ds1307->nvram->size - off;
824         if (unlikely(!count))
825                 return count;
826 
827         result = ds1307->write_block_data(client, ds1307->nvram_offset + off,
828                                                                 count, buf);
829         if (result < 0) {
830                 dev_err(&client->dev, "%s error %d\n", "nvram write", result);
831                 return result;
832         }
833         return count;
834 }
835 
836 /*----------------------------------------------------------------------*/
837 
838 static int ds1307_probe(struct i2c_client *client,
839                         const struct i2c_device_id *id)
840 {
841         struct ds1307           *ds1307;
842         int                     err = -ENODEV;
843         int                     tmp;
844         const struct chip_desc  *chip = &chips[id->driver_data];
845         struct i2c_adapter      *adapter = to_i2c_adapter(client->dev.parent);
846         bool                    want_irq = false;
847         unsigned char           *buf;
848         struct ds1307_platform_data *pdata = dev_get_platdata(&client->dev);
849         static const int        bbsqi_bitpos[] = {
850                 [ds_1337] = 0,
851                 [ds_1339] = DS1339_BIT_BBSQI,
852                 [ds_3231] = DS3231_BIT_BBSQW,
853         };
854         const struct rtc_class_ops *rtc_ops = &ds13xx_rtc_ops;
855 
856         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)
857             && !i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
858                 return -EIO;
859 
860         ds1307 = devm_kzalloc(&client->dev, sizeof(struct ds1307), GFP_KERNEL);
861         if (!ds1307)
862                 return -ENOMEM;
863 
864         i2c_set_clientdata(client, ds1307);
865 
866         ds1307->client  = client;
867         ds1307->type    = id->driver_data;
868 
869         if (pdata && pdata->trickle_charger_setup && chip->trickle_charger_reg)
870                 i2c_smbus_write_byte_data(client, chip->trickle_charger_reg,
871                         DS13XX_TRICKLE_CHARGER_MAGIC | pdata->trickle_charger_setup);
872 
873         buf = ds1307->regs;
874         if (i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) {
875                 ds1307->read_block_data = ds1307_native_smbus_read_block_data;
876                 ds1307->write_block_data = ds1307_native_smbus_write_block_data;
877         } else {
878                 ds1307->read_block_data = ds1307_read_block_data;
879                 ds1307->write_block_data = ds1307_write_block_data;
880         }
881 
882         switch (ds1307->type) {
883         case ds_1337:
884         case ds_1339:
885         case ds_3231:
886                 /* get registers that the "rtc" read below won't read... */
887                 tmp = ds1307->read_block_data(ds1307->client,
888                                 DS1337_REG_CONTROL, 2, buf);
889                 if (tmp != 2) {
890                         dev_dbg(&client->dev, "read error %d\n", tmp);
891                         err = -EIO;
892                         goto exit;
893                 }
894 
895                 /* oscillator off?  turn it on, so clock can tick. */
896                 if (ds1307->regs[0] & DS1337_BIT_nEOSC)
897                         ds1307->regs[0] &= ~DS1337_BIT_nEOSC;
898 
899                 /*
900                  * Using IRQ?  Disable the square wave and both alarms.
901                  * For some variants, be sure alarms can trigger when we're
902                  * running on Vbackup (BBSQI/BBSQW)
903                  */
904                 if (ds1307->client->irq > 0 && chip->alarm) {
905                         INIT_WORK(&ds1307->work, ds1307_work);
906 
907                         ds1307->regs[0] |= DS1337_BIT_INTCN
908                                         | bbsqi_bitpos[ds1307->type];
909                         ds1307->regs[0] &= ~(DS1337_BIT_A2IE | DS1337_BIT_A1IE);
910 
911                         want_irq = true;
912                 }
913 
914                 i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL,
915                                                         ds1307->regs[0]);
916 
917                 /* oscillator fault?  clear flag, and warn */
918                 if (ds1307->regs[1] & DS1337_BIT_OSF) {
919                         i2c_smbus_write_byte_data(client, DS1337_REG_STATUS,
920                                 ds1307->regs[1] & ~DS1337_BIT_OSF);
921                         dev_warn(&client->dev, "SET TIME!\n");
922                 }
923                 break;
924 
925         case rx_8025:
926                 tmp = i2c_smbus_read_i2c_block_data(ds1307->client,
927                                 RX8025_REG_CTRL1 << 4 | 0x08, 2, buf);
928                 if (tmp != 2) {
929                         dev_dbg(&client->dev, "read error %d\n", tmp);
930                         err = -EIO;
931                         goto exit;
932                 }
933 
934                 /* oscillator off?  turn it on, so clock can tick. */
935                 if (!(ds1307->regs[1] & RX8025_BIT_XST)) {
936                         ds1307->regs[1] |= RX8025_BIT_XST;
937                         i2c_smbus_write_byte_data(client,
938                                                   RX8025_REG_CTRL2 << 4 | 0x08,
939                                                   ds1307->regs[1]);
940                         dev_warn(&client->dev,
941                                  "oscillator stop detected - SET TIME!\n");
942                 }
943 
944                 if (ds1307->regs[1] & RX8025_BIT_PON) {
945                         ds1307->regs[1] &= ~RX8025_BIT_PON;
946                         i2c_smbus_write_byte_data(client,
947                                                   RX8025_REG_CTRL2 << 4 | 0x08,
948                                                   ds1307->regs[1]);
949                         dev_warn(&client->dev, "power-on detected\n");
950                 }
951 
952                 if (ds1307->regs[1] & RX8025_BIT_VDET) {
953                         ds1307->regs[1] &= ~RX8025_BIT_VDET;
954                         i2c_smbus_write_byte_data(client,
955                                                   RX8025_REG_CTRL2 << 4 | 0x08,
956                                                   ds1307->regs[1]);
957                         dev_warn(&client->dev, "voltage drop detected\n");
958                 }
959 
960                 /* make sure we are running in 24hour mode */
961                 if (!(ds1307->regs[0] & RX8025_BIT_2412)) {
962                         u8 hour;
963 
964                         /* switch to 24 hour mode */
965                         i2c_smbus_write_byte_data(client,
966                                                   RX8025_REG_CTRL1 << 4 | 0x08,
967                                                   ds1307->regs[0] |
968                                                   RX8025_BIT_2412);
969 
970                         tmp = i2c_smbus_read_i2c_block_data(ds1307->client,
971                                         RX8025_REG_CTRL1 << 4 | 0x08, 2, buf);
972                         if (tmp != 2) {
973                                 dev_dbg(&client->dev, "read error %d\n", tmp);
974                                 err = -EIO;
975                                 goto exit;
976                         }
977 
978                         /* correct hour */
979                         hour = bcd2bin(ds1307->regs[DS1307_REG_HOUR]);
980                         if (hour == 12)
981                                 hour = 0;
982                         if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
983                                 hour += 12;
984 
985                         i2c_smbus_write_byte_data(client,
986                                                   DS1307_REG_HOUR << 4 | 0x08,
987                                                   hour);
988                 }
989                 break;
990         case ds_1388:
991                 ds1307->offset = 1; /* Seconds starts at 1 */
992                 break;
993         case mcp7941x:
994                 rtc_ops = &mcp7941x_rtc_ops;
995                 if (ds1307->client->irq > 0 && chip->alarm) {
996                         INIT_WORK(&ds1307->work, mcp7941x_work);
997                         want_irq = true;
998                 }
999                 break;
1000         default:
1001                 break;
1002         }
1003 
1004 read_rtc:
1005         /* read RTC registers */
1006         tmp = ds1307->read_block_data(ds1307->client, ds1307->offset, 8, buf);
1007         if (tmp != 8) {
1008                 dev_dbg(&client->dev, "read error %d\n", tmp);
1009                 err = -EIO;
1010                 goto exit;
1011         }
1012 
1013         /*
1014          * minimal sanity checking; some chips (like DS1340) don't
1015          * specify the extra bits as must-be-zero, but there are
1016          * still a few values that are clearly out-of-range.
1017          */
1018         tmp = ds1307->regs[DS1307_REG_SECS];
1019         switch (ds1307->type) {
1020         case ds_1307:
1021         case m41t00:
1022                 /* clock halted?  turn it on, so clock can tick. */
1023                 if (tmp & DS1307_BIT_CH) {
1024                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
1025                         dev_warn(&client->dev, "SET TIME!\n");
1026                         goto read_rtc;
1027                 }
1028                 break;
1029         case ds_1338:
1030                 /* clock halted?  turn it on, so clock can tick. */
1031                 if (tmp & DS1307_BIT_CH)
1032                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
1033 
1034                 /* oscillator fault?  clear flag, and warn */
1035                 if (ds1307->regs[DS1307_REG_CONTROL] & DS1338_BIT_OSF) {
1036                         i2c_smbus_write_byte_data(client, DS1307_REG_CONTROL,
1037                                         ds1307->regs[DS1307_REG_CONTROL]
1038                                         & ~DS1338_BIT_OSF);
1039                         dev_warn(&client->dev, "SET TIME!\n");
1040                         goto read_rtc;
1041                 }
1042                 break;
1043         case ds_1340:
1044                 /* clock halted?  turn it on, so clock can tick. */
1045                 if (tmp & DS1340_BIT_nEOSC)
1046                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
1047 
1048                 tmp = i2c_smbus_read_byte_data(client, DS1340_REG_FLAG);
1049                 if (tmp < 0) {
1050                         dev_dbg(&client->dev, "read error %d\n", tmp);
1051                         err = -EIO;
1052                         goto exit;
1053                 }
1054 
1055                 /* oscillator fault?  clear flag, and warn */
1056                 if (tmp & DS1340_BIT_OSF) {
1057                         i2c_smbus_write_byte_data(client, DS1340_REG_FLAG, 0);
1058                         dev_warn(&client->dev, "SET TIME!\n");
1059                 }
1060                 break;
1061         case mcp7941x:
1062                 /* make sure that the backup battery is enabled */
1063                 if (!(ds1307->regs[DS1307_REG_WDAY] & MCP7941X_BIT_VBATEN)) {
1064                         i2c_smbus_write_byte_data(client, DS1307_REG_WDAY,
1065                                         ds1307->regs[DS1307_REG_WDAY]
1066                                         | MCP7941X_BIT_VBATEN);
1067                 }
1068 
1069                 /* clock halted?  turn it on, so clock can tick. */
1070                 if (!(tmp & MCP7941X_BIT_ST)) {
1071                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS,
1072                                         MCP7941X_BIT_ST);
1073                         dev_warn(&client->dev, "SET TIME!\n");
1074                         goto read_rtc;
1075                 }
1076 
1077                 break;
1078         default:
1079                 break;
1080         }
1081 
1082         tmp = ds1307->regs[DS1307_REG_HOUR];
1083         switch (ds1307->type) {
1084         case ds_1340:
1085         case m41t00:
1086                 /*
1087                  * NOTE: ignores century bits; fix before deploying
1088                  * systems that will run through year 2100.
1089                  */
1090                 break;
1091         case rx_8025:
1092                 break;
1093         default:
1094                 if (!(tmp & DS1307_BIT_12HR))
1095                         break;
1096 
1097                 /*
1098                  * Be sure we're in 24 hour mode.  Multi-master systems
1099                  * take note...
1100                  */
1101                 tmp = bcd2bin(tmp & 0x1f);
1102                 if (tmp == 12)
1103                         tmp = 0;
1104                 if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
1105                         tmp += 12;
1106                 i2c_smbus_write_byte_data(client,
1107                                 ds1307->offset + DS1307_REG_HOUR,
1108                                 bin2bcd(tmp));
1109         }
1110 
1111         device_set_wakeup_capable(&client->dev, want_irq);
1112         ds1307->rtc = devm_rtc_device_register(&client->dev, client->name,
1113                                 rtc_ops, THIS_MODULE);
1114         if (IS_ERR(ds1307->rtc)) {
1115                 return PTR_ERR(ds1307->rtc);
1116         }
1117 
1118         if (want_irq) {
1119                 err = request_irq(client->irq, ds1307_irq, IRQF_SHARED,
1120                           ds1307->rtc->name, client);
1121                 if (err) {
1122                         client->irq = 0;
1123                         dev_err(&client->dev, "unable to request IRQ!\n");
1124                 } else {
1125 
1126                         set_bit(HAS_ALARM, &ds1307->flags);
1127                         dev_dbg(&client->dev, "got IRQ %d\n", client->irq);
1128                 }
1129         }
1130 
1131         if (chip->nvram_size) {
1132 
1133                 ds1307->nvram = devm_kzalloc(&client->dev,
1134                                         sizeof(struct bin_attribute),
1135                                         GFP_KERNEL);
1136                 if (!ds1307->nvram) {
1137                         dev_err(&client->dev, "cannot allocate memory for nvram sysfs\n");
1138                 } else {
1139 
1140                         ds1307->nvram->attr.name = "nvram";
1141                         ds1307->nvram->attr.mode = S_IRUGO | S_IWUSR;
1142 
1143                         sysfs_bin_attr_init(ds1307->nvram);
1144 
1145                         ds1307->nvram->read = ds1307_nvram_read;
1146                         ds1307->nvram->write = ds1307_nvram_write;
1147                         ds1307->nvram->size = chip->nvram_size;
1148                         ds1307->nvram_offset = chip->nvram_offset;
1149 
1150                         err = sysfs_create_bin_file(&client->dev.kobj,
1151                                                     ds1307->nvram);
1152                         if (err) {
1153                                 dev_err(&client->dev,
1154                                         "unable to create sysfs file: %s\n",
1155                                         ds1307->nvram->attr.name);
1156                         } else {
1157                                 set_bit(HAS_NVRAM, &ds1307->flags);
1158                                 dev_info(&client->dev, "%zu bytes nvram\n",
1159                                          ds1307->nvram->size);
1160                         }
1161                 }
1162         }
1163 
1164         return 0;
1165 
1166 exit:
1167         return err;
1168 }
1169 
1170 static int ds1307_remove(struct i2c_client *client)
1171 {
1172         struct ds1307 *ds1307 = i2c_get_clientdata(client);
1173 
1174         if (test_and_clear_bit(HAS_ALARM, &ds1307->flags)) {
1175                 free_irq(client->irq, client);
1176                 cancel_work_sync(&ds1307->work);
1177         }
1178 
1179         if (test_and_clear_bit(HAS_NVRAM, &ds1307->flags))
1180                 sysfs_remove_bin_file(&client->dev.kobj, ds1307->nvram);
1181 
1182         return 0;
1183 }
1184 
1185 static struct i2c_driver ds1307_driver = {
1186         .driver = {
1187                 .name   = "rtc-ds1307",
1188                 .owner  = THIS_MODULE,
1189         },
1190         .probe          = ds1307_probe,
1191         .remove         = ds1307_remove,
1192         .id_table       = ds1307_id,
1193 };
1194 
1195 module_i2c_driver(ds1307_driver);
1196 
1197 MODULE_DESCRIPTION("RTC driver for DS1307 and similar chips");
1198 MODULE_LICENSE("GPL");
1199 

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