Version:  2.0.40 2.2.26 2.4.37 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0 4.1 4.2

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         mcp794xx,
 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 MCP794XX_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 MCP794XX_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         u8                      trickle_charger_setup;
130         u8                      (*do_trickle_setup)(struct i2c_client *, uint32_t, bool);
131 };
132 
133 static u8 do_trickle_setup_ds1339(struct i2c_client *,
134                                   uint32_t ohms, bool diode);
135 
136 static struct chip_desc chips[last_ds_type] = {
137         [ds_1307] = {
138                 .nvram_offset   = 8,
139                 .nvram_size     = 56,
140         },
141         [ds_1337] = {
142                 .alarm          = 1,
143         },
144         [ds_1338] = {
145                 .nvram_offset   = 8,
146                 .nvram_size     = 56,
147         },
148         [ds_1339] = {
149                 .alarm          = 1,
150                 .trickle_charger_reg = 0x10,
151                 .do_trickle_setup = &do_trickle_setup_ds1339,
152         },
153         [ds_1340] = {
154                 .trickle_charger_reg = 0x08,
155         },
156         [ds_1388] = {
157                 .trickle_charger_reg = 0x0a,
158         },
159         [ds_3231] = {
160                 .alarm          = 1,
161         },
162         [mcp794xx] = {
163                 .alarm          = 1,
164                 /* this is battery backed SRAM */
165                 .nvram_offset   = 0x20,
166                 .nvram_size     = 0x40,
167         },
168 };
169 
170 static const struct i2c_device_id ds1307_id[] = {
171         { "ds1307", ds_1307 },
172         { "ds1337", ds_1337 },
173         { "ds1338", ds_1338 },
174         { "ds1339", ds_1339 },
175         { "ds1388", ds_1388 },
176         { "ds1340", ds_1340 },
177         { "ds3231", ds_3231 },
178         { "m41t00", m41t00 },
179         { "mcp7940x", mcp794xx },
180         { "mcp7941x", mcp794xx },
181         { "pt7c4338", ds_1307 },
182         { "rx8025", rx_8025 },
183         { }
184 };
185 MODULE_DEVICE_TABLE(i2c, ds1307_id);
186 
187 /*----------------------------------------------------------------------*/
188 
189 #define BLOCK_DATA_MAX_TRIES 10
190 
191 static s32 ds1307_read_block_data_once(const struct i2c_client *client,
192                                        u8 command, u8 length, u8 *values)
193 {
194         s32 i, data;
195 
196         for (i = 0; i < length; i++) {
197                 data = i2c_smbus_read_byte_data(client, command + i);
198                 if (data < 0)
199                         return data;
200                 values[i] = data;
201         }
202         return i;
203 }
204 
205 static s32 ds1307_read_block_data(const struct i2c_client *client, u8 command,
206                                   u8 length, u8 *values)
207 {
208         u8 oldvalues[255];
209         s32 ret;
210         int tries = 0;
211 
212         dev_dbg(&client->dev, "ds1307_read_block_data (length=%d)\n", length);
213         ret = ds1307_read_block_data_once(client, command, length, values);
214         if (ret < 0)
215                 return ret;
216         do {
217                 if (++tries > BLOCK_DATA_MAX_TRIES) {
218                         dev_err(&client->dev,
219                                 "ds1307_read_block_data failed\n");
220                         return -EIO;
221                 }
222                 memcpy(oldvalues, values, length);
223                 ret = ds1307_read_block_data_once(client, command, length,
224                                                   values);
225                 if (ret < 0)
226                         return ret;
227         } while (memcmp(oldvalues, values, length));
228         return length;
229 }
230 
231 static s32 ds1307_write_block_data(const struct i2c_client *client, u8 command,
232                                    u8 length, const u8 *values)
233 {
234         u8 currvalues[255];
235         int tries = 0;
236 
237         dev_dbg(&client->dev, "ds1307_write_block_data (length=%d)\n", length);
238         do {
239                 s32 i, ret;
240 
241                 if (++tries > BLOCK_DATA_MAX_TRIES) {
242                         dev_err(&client->dev,
243                                 "ds1307_write_block_data failed\n");
244                         return -EIO;
245                 }
246                 for (i = 0; i < length; i++) {
247                         ret = i2c_smbus_write_byte_data(client, command + i,
248                                                         values[i]);
249                         if (ret < 0)
250                                 return ret;
251                 }
252                 ret = ds1307_read_block_data_once(client, command, length,
253                                                   currvalues);
254                 if (ret < 0)
255                         return ret;
256         } while (memcmp(currvalues, values, length));
257         return length;
258 }
259 
260 /*----------------------------------------------------------------------*/
261 
262 /* These RTC devices are not designed to be connected to a SMbus adapter.
263    SMbus limits block operations length to 32 bytes, whereas it's not
264    limited on I2C buses. As a result, accesses may exceed 32 bytes;
265    in that case, split them into smaller blocks */
266 
267 static s32 ds1307_native_smbus_write_block_data(const struct i2c_client *client,
268                                 u8 command, u8 length, const u8 *values)
269 {
270         u8 suboffset = 0;
271 
272         if (length <= I2C_SMBUS_BLOCK_MAX)
273                 return i2c_smbus_write_i2c_block_data(client,
274                                         command, length, values);
275 
276         while (suboffset < length) {
277                 s32 retval = i2c_smbus_write_i2c_block_data(client,
278                                 command + suboffset,
279                                 min(I2C_SMBUS_BLOCK_MAX, length - suboffset),
280                                 values + suboffset);
281                 if (retval < 0)
282                         return retval;
283 
284                 suboffset += I2C_SMBUS_BLOCK_MAX;
285         }
286         return length;
287 }
288 
289 static s32 ds1307_native_smbus_read_block_data(const struct i2c_client *client,
290                                 u8 command, u8 length, u8 *values)
291 {
292         u8 suboffset = 0;
293 
294         if (length <= I2C_SMBUS_BLOCK_MAX)
295                 return i2c_smbus_read_i2c_block_data(client,
296                                         command, length, values);
297 
298         while (suboffset < length) {
299                 s32 retval = i2c_smbus_read_i2c_block_data(client,
300                                 command + suboffset,
301                                 min(I2C_SMBUS_BLOCK_MAX, length - suboffset),
302                                 values + suboffset);
303                 if (retval < 0)
304                         return retval;
305 
306                 suboffset += I2C_SMBUS_BLOCK_MAX;
307         }
308         return length;
309 }
310 
311 /*----------------------------------------------------------------------*/
312 
313 /*
314  * The IRQ logic includes a "real" handler running in IRQ context just
315  * long enough to schedule this workqueue entry.   We need a task context
316  * to talk to the RTC, since I2C I/O calls require that; and disable the
317  * IRQ until we clear its status on the chip, so that this handler can
318  * work with any type of triggering (not just falling edge).
319  *
320  * The ds1337 and ds1339 both have two alarms, but we only use the first
321  * one (with a "seconds" field).  For ds1337 we expect nINTA is our alarm
322  * signal; ds1339 chips have only one alarm signal.
323  */
324 static void ds1307_work(struct work_struct *work)
325 {
326         struct ds1307           *ds1307;
327         struct i2c_client       *client;
328         struct mutex            *lock;
329         int                     stat, control;
330 
331         ds1307 = container_of(work, struct ds1307, work);
332         client = ds1307->client;
333         lock = &ds1307->rtc->ops_lock;
334 
335         mutex_lock(lock);
336         stat = i2c_smbus_read_byte_data(client, DS1337_REG_STATUS);
337         if (stat < 0)
338                 goto out;
339 
340         if (stat & DS1337_BIT_A1I) {
341                 stat &= ~DS1337_BIT_A1I;
342                 i2c_smbus_write_byte_data(client, DS1337_REG_STATUS, stat);
343 
344                 control = i2c_smbus_read_byte_data(client, DS1337_REG_CONTROL);
345                 if (control < 0)
346                         goto out;
347 
348                 control &= ~DS1337_BIT_A1IE;
349                 i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL, control);
350 
351                 rtc_update_irq(ds1307->rtc, 1, RTC_AF | RTC_IRQF);
352         }
353 
354 out:
355         if (test_bit(HAS_ALARM, &ds1307->flags))
356                 enable_irq(client->irq);
357         mutex_unlock(lock);
358 }
359 
360 static irqreturn_t ds1307_irq(int irq, void *dev_id)
361 {
362         struct i2c_client       *client = dev_id;
363         struct ds1307           *ds1307 = i2c_get_clientdata(client);
364 
365         disable_irq_nosync(irq);
366         schedule_work(&ds1307->work);
367         return IRQ_HANDLED;
368 }
369 
370 /*----------------------------------------------------------------------*/
371 
372 static int ds1307_get_time(struct device *dev, struct rtc_time *t)
373 {
374         struct ds1307   *ds1307 = dev_get_drvdata(dev);
375         int             tmp;
376 
377         /* read the RTC date and time registers all at once */
378         tmp = ds1307->read_block_data(ds1307->client,
379                 ds1307->offset, 7, ds1307->regs);
380         if (tmp != 7) {
381                 dev_err(dev, "%s error %d\n", "read", tmp);
382                 return -EIO;
383         }
384 
385         dev_dbg(dev, "%s: %7ph\n", "read", ds1307->regs);
386 
387         t->tm_sec = bcd2bin(ds1307->regs[DS1307_REG_SECS] & 0x7f);
388         t->tm_min = bcd2bin(ds1307->regs[DS1307_REG_MIN] & 0x7f);
389         tmp = ds1307->regs[DS1307_REG_HOUR] & 0x3f;
390         t->tm_hour = bcd2bin(tmp);
391         t->tm_wday = bcd2bin(ds1307->regs[DS1307_REG_WDAY] & 0x07) - 1;
392         t->tm_mday = bcd2bin(ds1307->regs[DS1307_REG_MDAY] & 0x3f);
393         tmp = ds1307->regs[DS1307_REG_MONTH] & 0x1f;
394         t->tm_mon = bcd2bin(tmp) - 1;
395 
396         /* assume 20YY not 19YY, and ignore DS1337_BIT_CENTURY */
397         t->tm_year = bcd2bin(ds1307->regs[DS1307_REG_YEAR]) + 100;
398 
399         dev_dbg(dev, "%s secs=%d, mins=%d, "
400                 "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
401                 "read", t->tm_sec, t->tm_min,
402                 t->tm_hour, t->tm_mday,
403                 t->tm_mon, t->tm_year, t->tm_wday);
404 
405         /* initial clock setting can be undefined */
406         return rtc_valid_tm(t);
407 }
408 
409 static int ds1307_set_time(struct device *dev, struct rtc_time *t)
410 {
411         struct ds1307   *ds1307 = dev_get_drvdata(dev);
412         int             result;
413         int             tmp;
414         u8              *buf = ds1307->regs;
415 
416         dev_dbg(dev, "%s secs=%d, mins=%d, "
417                 "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
418                 "write", t->tm_sec, t->tm_min,
419                 t->tm_hour, t->tm_mday,
420                 t->tm_mon, t->tm_year, t->tm_wday);
421 
422         buf[DS1307_REG_SECS] = bin2bcd(t->tm_sec);
423         buf[DS1307_REG_MIN] = bin2bcd(t->tm_min);
424         buf[DS1307_REG_HOUR] = bin2bcd(t->tm_hour);
425         buf[DS1307_REG_WDAY] = bin2bcd(t->tm_wday + 1);
426         buf[DS1307_REG_MDAY] = bin2bcd(t->tm_mday);
427         buf[DS1307_REG_MONTH] = bin2bcd(t->tm_mon + 1);
428 
429         /* assume 20YY not 19YY */
430         tmp = t->tm_year - 100;
431         buf[DS1307_REG_YEAR] = bin2bcd(tmp);
432 
433         switch (ds1307->type) {
434         case ds_1337:
435         case ds_1339:
436         case ds_3231:
437                 buf[DS1307_REG_MONTH] |= DS1337_BIT_CENTURY;
438                 break;
439         case ds_1340:
440                 buf[DS1307_REG_HOUR] |= DS1340_BIT_CENTURY_EN
441                                 | DS1340_BIT_CENTURY;
442                 break;
443         case mcp794xx:
444                 /*
445                  * these bits were cleared when preparing the date/time
446                  * values and need to be set again before writing the
447                  * buffer out to the device.
448                  */
449                 buf[DS1307_REG_SECS] |= MCP794XX_BIT_ST;
450                 buf[DS1307_REG_WDAY] |= MCP794XX_BIT_VBATEN;
451                 break;
452         default:
453                 break;
454         }
455 
456         dev_dbg(dev, "%s: %7ph\n", "write", buf);
457 
458         result = ds1307->write_block_data(ds1307->client,
459                 ds1307->offset, 7, buf);
460         if (result < 0) {
461                 dev_err(dev, "%s error %d\n", "write", result);
462                 return result;
463         }
464         return 0;
465 }
466 
467 static int ds1337_read_alarm(struct device *dev, struct rtc_wkalrm *t)
468 {
469         struct i2c_client       *client = to_i2c_client(dev);
470         struct ds1307           *ds1307 = i2c_get_clientdata(client);
471         int                     ret;
472 
473         if (!test_bit(HAS_ALARM, &ds1307->flags))
474                 return -EINVAL;
475 
476         /* read all ALARM1, ALARM2, and status registers at once */
477         ret = ds1307->read_block_data(client,
478                         DS1339_REG_ALARM1_SECS, 9, ds1307->regs);
479         if (ret != 9) {
480                 dev_err(dev, "%s error %d\n", "alarm read", ret);
481                 return -EIO;
482         }
483 
484         dev_dbg(dev, "%s: %02x %02x %02x %02x, %02x %02x %02x, %02x %02x\n",
485                         "alarm read",
486                         ds1307->regs[0], ds1307->regs[1],
487                         ds1307->regs[2], ds1307->regs[3],
488                         ds1307->regs[4], ds1307->regs[5],
489                         ds1307->regs[6], ds1307->regs[7],
490                         ds1307->regs[8]);
491 
492         /*
493          * report alarm time (ALARM1); assume 24 hour and day-of-month modes,
494          * and that all four fields are checked matches
495          */
496         t->time.tm_sec = bcd2bin(ds1307->regs[0] & 0x7f);
497         t->time.tm_min = bcd2bin(ds1307->regs[1] & 0x7f);
498         t->time.tm_hour = bcd2bin(ds1307->regs[2] & 0x3f);
499         t->time.tm_mday = bcd2bin(ds1307->regs[3] & 0x3f);
500         t->time.tm_mon = -1;
501         t->time.tm_year = -1;
502         t->time.tm_wday = -1;
503         t->time.tm_yday = -1;
504         t->time.tm_isdst = -1;
505 
506         /* ... and status */
507         t->enabled = !!(ds1307->regs[7] & DS1337_BIT_A1IE);
508         t->pending = !!(ds1307->regs[8] & DS1337_BIT_A1I);
509 
510         dev_dbg(dev, "%s secs=%d, mins=%d, "
511                 "hours=%d, mday=%d, enabled=%d, pending=%d\n",
512                 "alarm read", t->time.tm_sec, t->time.tm_min,
513                 t->time.tm_hour, t->time.tm_mday,
514                 t->enabled, t->pending);
515 
516         return 0;
517 }
518 
519 static int ds1337_set_alarm(struct device *dev, struct rtc_wkalrm *t)
520 {
521         struct i2c_client       *client = to_i2c_client(dev);
522         struct ds1307           *ds1307 = i2c_get_clientdata(client);
523         unsigned char           *buf = ds1307->regs;
524         u8                      control, status;
525         int                     ret;
526 
527         if (!test_bit(HAS_ALARM, &ds1307->flags))
528                 return -EINVAL;
529 
530         dev_dbg(dev, "%s secs=%d, mins=%d, "
531                 "hours=%d, mday=%d, enabled=%d, pending=%d\n",
532                 "alarm set", t->time.tm_sec, t->time.tm_min,
533                 t->time.tm_hour, t->time.tm_mday,
534                 t->enabled, t->pending);
535 
536         /* read current status of both alarms and the chip */
537         ret = ds1307->read_block_data(client,
538                         DS1339_REG_ALARM1_SECS, 9, buf);
539         if (ret != 9) {
540                 dev_err(dev, "%s error %d\n", "alarm write", ret);
541                 return -EIO;
542         }
543         control = ds1307->regs[7];
544         status = ds1307->regs[8];
545 
546         dev_dbg(dev, "%s: %02x %02x %02x %02x, %02x %02x %02x, %02x %02x\n",
547                         "alarm set (old status)",
548                         ds1307->regs[0], ds1307->regs[1],
549                         ds1307->regs[2], ds1307->regs[3],
550                         ds1307->regs[4], ds1307->regs[5],
551                         ds1307->regs[6], control, status);
552 
553         /* set ALARM1, using 24 hour and day-of-month modes */
554         buf[0] = bin2bcd(t->time.tm_sec);
555         buf[1] = bin2bcd(t->time.tm_min);
556         buf[2] = bin2bcd(t->time.tm_hour);
557         buf[3] = bin2bcd(t->time.tm_mday);
558 
559         /* set ALARM2 to non-garbage */
560         buf[4] = 0;
561         buf[5] = 0;
562         buf[6] = 0;
563 
564         /* optionally enable ALARM1 */
565         buf[7] = control & ~(DS1337_BIT_A1IE | DS1337_BIT_A2IE);
566         if (t->enabled) {
567                 dev_dbg(dev, "alarm IRQ armed\n");
568                 buf[7] |= DS1337_BIT_A1IE;      /* only ALARM1 is used */
569         }
570         buf[8] = status & ~(DS1337_BIT_A1I | DS1337_BIT_A2I);
571 
572         ret = ds1307->write_block_data(client,
573                         DS1339_REG_ALARM1_SECS, 9, buf);
574         if (ret < 0) {
575                 dev_err(dev, "can't set alarm time\n");
576                 return ret;
577         }
578 
579         return 0;
580 }
581 
582 static int ds1307_alarm_irq_enable(struct device *dev, unsigned int enabled)
583 {
584         struct i2c_client       *client = to_i2c_client(dev);
585         struct ds1307           *ds1307 = i2c_get_clientdata(client);
586         int                     ret;
587 
588         if (!test_bit(HAS_ALARM, &ds1307->flags))
589                 return -ENOTTY;
590 
591         ret = i2c_smbus_read_byte_data(client, DS1337_REG_CONTROL);
592         if (ret < 0)
593                 return ret;
594 
595         if (enabled)
596                 ret |= DS1337_BIT_A1IE;
597         else
598                 ret &= ~DS1337_BIT_A1IE;
599 
600         ret = i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL, ret);
601         if (ret < 0)
602                 return ret;
603 
604         return 0;
605 }
606 
607 static const struct rtc_class_ops ds13xx_rtc_ops = {
608         .read_time      = ds1307_get_time,
609         .set_time       = ds1307_set_time,
610         .read_alarm     = ds1337_read_alarm,
611         .set_alarm      = ds1337_set_alarm,
612         .alarm_irq_enable = ds1307_alarm_irq_enable,
613 };
614 
615 /*----------------------------------------------------------------------*/
616 
617 /*
618  * Alarm support for mcp794xx devices.
619  */
620 
621 #define MCP794XX_REG_CONTROL            0x07
622 #       define MCP794XX_BIT_ALM0_EN     0x10
623 #       define MCP794XX_BIT_ALM1_EN     0x20
624 #define MCP794XX_REG_ALARM0_BASE        0x0a
625 #define MCP794XX_REG_ALARM0_CTRL        0x0d
626 #define MCP794XX_REG_ALARM1_BASE        0x11
627 #define MCP794XX_REG_ALARM1_CTRL        0x14
628 #       define MCP794XX_BIT_ALMX_IF     (1 << 3)
629 #       define MCP794XX_BIT_ALMX_C0     (1 << 4)
630 #       define MCP794XX_BIT_ALMX_C1     (1 << 5)
631 #       define MCP794XX_BIT_ALMX_C2     (1 << 6)
632 #       define MCP794XX_BIT_ALMX_POL    (1 << 7)
633 #       define MCP794XX_MSK_ALMX_MATCH  (MCP794XX_BIT_ALMX_C0 | \
634                                          MCP794XX_BIT_ALMX_C1 | \
635                                          MCP794XX_BIT_ALMX_C2)
636 
637 static void mcp794xx_work(struct work_struct *work)
638 {
639         struct ds1307 *ds1307 = container_of(work, struct ds1307, work);
640         struct i2c_client *client = ds1307->client;
641         int reg, ret;
642 
643         mutex_lock(&ds1307->rtc->ops_lock);
644 
645         /* Check and clear alarm 0 interrupt flag. */
646         reg = i2c_smbus_read_byte_data(client, MCP794XX_REG_ALARM0_CTRL);
647         if (reg < 0)
648                 goto out;
649         if (!(reg & MCP794XX_BIT_ALMX_IF))
650                 goto out;
651         reg &= ~MCP794XX_BIT_ALMX_IF;
652         ret = i2c_smbus_write_byte_data(client, MCP794XX_REG_ALARM0_CTRL, reg);
653         if (ret < 0)
654                 goto out;
655 
656         /* Disable alarm 0. */
657         reg = i2c_smbus_read_byte_data(client, MCP794XX_REG_CONTROL);
658         if (reg < 0)
659                 goto out;
660         reg &= ~MCP794XX_BIT_ALM0_EN;
661         ret = i2c_smbus_write_byte_data(client, MCP794XX_REG_CONTROL, reg);
662         if (ret < 0)
663                 goto out;
664 
665         rtc_update_irq(ds1307->rtc, 1, RTC_AF | RTC_IRQF);
666 
667 out:
668         if (test_bit(HAS_ALARM, &ds1307->flags))
669                 enable_irq(client->irq);
670         mutex_unlock(&ds1307->rtc->ops_lock);
671 }
672 
673 static int mcp794xx_read_alarm(struct device *dev, struct rtc_wkalrm *t)
674 {
675         struct i2c_client *client = to_i2c_client(dev);
676         struct ds1307 *ds1307 = i2c_get_clientdata(client);
677         u8 *regs = ds1307->regs;
678         int ret;
679 
680         if (!test_bit(HAS_ALARM, &ds1307->flags))
681                 return -EINVAL;
682 
683         /* Read control and alarm 0 registers. */
684         ret = ds1307->read_block_data(client, MCP794XX_REG_CONTROL, 10, regs);
685         if (ret < 0)
686                 return ret;
687 
688         t->enabled = !!(regs[0] & MCP794XX_BIT_ALM0_EN);
689 
690         /* Report alarm 0 time assuming 24-hour and day-of-month modes. */
691         t->time.tm_sec = bcd2bin(ds1307->regs[3] & 0x7f);
692         t->time.tm_min = bcd2bin(ds1307->regs[4] & 0x7f);
693         t->time.tm_hour = bcd2bin(ds1307->regs[5] & 0x3f);
694         t->time.tm_wday = bcd2bin(ds1307->regs[6] & 0x7) - 1;
695         t->time.tm_mday = bcd2bin(ds1307->regs[7] & 0x3f);
696         t->time.tm_mon = bcd2bin(ds1307->regs[8] & 0x1f) - 1;
697         t->time.tm_year = -1;
698         t->time.tm_yday = -1;
699         t->time.tm_isdst = -1;
700 
701         dev_dbg(dev, "%s, sec=%d min=%d hour=%d wday=%d mday=%d mon=%d "
702                 "enabled=%d polarity=%d irq=%d match=%d\n", __func__,
703                 t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
704                 t->time.tm_wday, t->time.tm_mday, t->time.tm_mon, t->enabled,
705                 !!(ds1307->regs[6] & MCP794XX_BIT_ALMX_POL),
706                 !!(ds1307->regs[6] & MCP794XX_BIT_ALMX_IF),
707                 (ds1307->regs[6] & MCP794XX_MSK_ALMX_MATCH) >> 4);
708 
709         return 0;
710 }
711 
712 static int mcp794xx_set_alarm(struct device *dev, struct rtc_wkalrm *t)
713 {
714         struct i2c_client *client = to_i2c_client(dev);
715         struct ds1307 *ds1307 = i2c_get_clientdata(client);
716         unsigned char *regs = ds1307->regs;
717         int ret;
718 
719         if (!test_bit(HAS_ALARM, &ds1307->flags))
720                 return -EINVAL;
721 
722         dev_dbg(dev, "%s, sec=%d min=%d hour=%d wday=%d mday=%d mon=%d "
723                 "enabled=%d pending=%d\n", __func__,
724                 t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
725                 t->time.tm_wday, t->time.tm_mday, t->time.tm_mon,
726                 t->enabled, t->pending);
727 
728         /* Read control and alarm 0 registers. */
729         ret = ds1307->read_block_data(client, MCP794XX_REG_CONTROL, 10, regs);
730         if (ret < 0)
731                 return ret;
732 
733         /* Set alarm 0, using 24-hour and day-of-month modes. */
734         regs[3] = bin2bcd(t->time.tm_sec);
735         regs[4] = bin2bcd(t->time.tm_min);
736         regs[5] = bin2bcd(t->time.tm_hour);
737         regs[6] = bin2bcd(t->time.tm_wday) + 1;
738         regs[7] = bin2bcd(t->time.tm_mday);
739         regs[8] = bin2bcd(t->time.tm_mon) + 1;
740 
741         /* Clear the alarm 0 interrupt flag. */
742         regs[6] &= ~MCP794XX_BIT_ALMX_IF;
743         /* Set alarm match: second, minute, hour, day, date, month. */
744         regs[6] |= MCP794XX_MSK_ALMX_MATCH;
745         /* Disable interrupt. We will not enable until completely programmed */
746         regs[0] &= ~MCP794XX_BIT_ALM0_EN;
747 
748         ret = ds1307->write_block_data(client, MCP794XX_REG_CONTROL, 10, regs);
749         if (ret < 0)
750                 return ret;
751 
752         if (!t->enabled)
753                 return 0;
754         regs[0] |= MCP794XX_BIT_ALM0_EN;
755         return i2c_smbus_write_byte_data(client, MCP794XX_REG_CONTROL, regs[0]);
756 }
757 
758 static int mcp794xx_alarm_irq_enable(struct device *dev, unsigned int enabled)
759 {
760         struct i2c_client *client = to_i2c_client(dev);
761         struct ds1307 *ds1307 = i2c_get_clientdata(client);
762         int reg;
763 
764         if (!test_bit(HAS_ALARM, &ds1307->flags))
765                 return -EINVAL;
766 
767         reg = i2c_smbus_read_byte_data(client, MCP794XX_REG_CONTROL);
768         if (reg < 0)
769                 return reg;
770 
771         if (enabled)
772                 reg |= MCP794XX_BIT_ALM0_EN;
773         else
774                 reg &= ~MCP794XX_BIT_ALM0_EN;
775 
776         return i2c_smbus_write_byte_data(client, MCP794XX_REG_CONTROL, reg);
777 }
778 
779 static const struct rtc_class_ops mcp794xx_rtc_ops = {
780         .read_time      = ds1307_get_time,
781         .set_time       = ds1307_set_time,
782         .read_alarm     = mcp794xx_read_alarm,
783         .set_alarm      = mcp794xx_set_alarm,
784         .alarm_irq_enable = mcp794xx_alarm_irq_enable,
785 };
786 
787 /*----------------------------------------------------------------------*/
788 
789 static ssize_t
790 ds1307_nvram_read(struct file *filp, struct kobject *kobj,
791                 struct bin_attribute *attr,
792                 char *buf, loff_t off, size_t count)
793 {
794         struct i2c_client       *client;
795         struct ds1307           *ds1307;
796         int                     result;
797 
798         client = kobj_to_i2c_client(kobj);
799         ds1307 = i2c_get_clientdata(client);
800 
801         if (unlikely(off >= ds1307->nvram->size))
802                 return 0;
803         if ((off + count) > ds1307->nvram->size)
804                 count = ds1307->nvram->size - off;
805         if (unlikely(!count))
806                 return count;
807 
808         result = ds1307->read_block_data(client, ds1307->nvram_offset + off,
809                                                                 count, buf);
810         if (result < 0)
811                 dev_err(&client->dev, "%s error %d\n", "nvram read", result);
812         return result;
813 }
814 
815 static ssize_t
816 ds1307_nvram_write(struct file *filp, struct kobject *kobj,
817                 struct bin_attribute *attr,
818                 char *buf, loff_t off, size_t count)
819 {
820         struct i2c_client       *client;
821         struct ds1307           *ds1307;
822         int                     result;
823 
824         client = kobj_to_i2c_client(kobj);
825         ds1307 = i2c_get_clientdata(client);
826 
827         if (unlikely(off >= ds1307->nvram->size))
828                 return -EFBIG;
829         if ((off + count) > ds1307->nvram->size)
830                 count = ds1307->nvram->size - off;
831         if (unlikely(!count))
832                 return count;
833 
834         result = ds1307->write_block_data(client, ds1307->nvram_offset + off,
835                                                                 count, buf);
836         if (result < 0) {
837                 dev_err(&client->dev, "%s error %d\n", "nvram write", result);
838                 return result;
839         }
840         return count;
841 }
842 
843 
844 /*----------------------------------------------------------------------*/
845 
846 static u8 do_trickle_setup_ds1339(struct i2c_client *client,
847                                   uint32_t ohms, bool diode)
848 {
849         u8 setup = (diode) ? DS1307_TRICKLE_CHARGER_DIODE :
850                 DS1307_TRICKLE_CHARGER_NO_DIODE;
851 
852         switch (ohms) {
853         case 250:
854                 setup |= DS1307_TRICKLE_CHARGER_250_OHM;
855                 break;
856         case 2000:
857                 setup |= DS1307_TRICKLE_CHARGER_2K_OHM;
858                 break;
859         case 4000:
860                 setup |= DS1307_TRICKLE_CHARGER_4K_OHM;
861                 break;
862         default:
863                 dev_warn(&client->dev,
864                          "Unsupported ohm value %u in dt\n", ohms);
865                 return 0;
866         }
867         return setup;
868 }
869 
870 static void ds1307_trickle_of_init(struct i2c_client *client,
871                                    struct chip_desc *chip)
872 {
873         uint32_t ohms = 0;
874         bool diode = true;
875 
876         if (!chip->do_trickle_setup)
877                 goto out;
878         if (of_property_read_u32(client->dev.of_node, "trickle-resistor-ohms" , &ohms))
879                 goto out;
880         if (of_property_read_bool(client->dev.of_node, "trickle-diode-disable"))
881                 diode = false;
882         chip->trickle_charger_setup = chip->do_trickle_setup(client,
883                                                              ohms, diode);
884 out:
885         return;
886 }
887 
888 static int ds1307_probe(struct i2c_client *client,
889                         const struct i2c_device_id *id)
890 {
891         struct ds1307           *ds1307;
892         int                     err = -ENODEV;
893         int                     tmp;
894         struct chip_desc        *chip = &chips[id->driver_data];
895         struct i2c_adapter      *adapter = to_i2c_adapter(client->dev.parent);
896         bool                    want_irq = false;
897         unsigned char           *buf;
898         struct ds1307_platform_data *pdata = dev_get_platdata(&client->dev);
899         static const int        bbsqi_bitpos[] = {
900                 [ds_1337] = 0,
901                 [ds_1339] = DS1339_BIT_BBSQI,
902                 [ds_3231] = DS3231_BIT_BBSQW,
903         };
904         const struct rtc_class_ops *rtc_ops = &ds13xx_rtc_ops;
905 
906         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)
907             && !i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
908                 return -EIO;
909 
910         ds1307 = devm_kzalloc(&client->dev, sizeof(struct ds1307), GFP_KERNEL);
911         if (!ds1307)
912                 return -ENOMEM;
913 
914         i2c_set_clientdata(client, ds1307);
915 
916         ds1307->client  = client;
917         ds1307->type    = id->driver_data;
918 
919         if (!pdata && client->dev.of_node)
920                 ds1307_trickle_of_init(client, chip);
921         else if (pdata && pdata->trickle_charger_setup)
922                 chip->trickle_charger_setup = pdata->trickle_charger_setup;
923 
924         if (chip->trickle_charger_setup && chip->trickle_charger_reg) {
925                 dev_dbg(&client->dev, "writing trickle charger info 0x%x to 0x%x\n",
926                     DS13XX_TRICKLE_CHARGER_MAGIC | chip->trickle_charger_setup,
927                     chip->trickle_charger_reg);
928                 i2c_smbus_write_byte_data(client, chip->trickle_charger_reg,
929                     DS13XX_TRICKLE_CHARGER_MAGIC |
930                     chip->trickle_charger_setup);
931         }
932 
933         buf = ds1307->regs;
934         if (i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) {
935                 ds1307->read_block_data = ds1307_native_smbus_read_block_data;
936                 ds1307->write_block_data = ds1307_native_smbus_write_block_data;
937         } else {
938                 ds1307->read_block_data = ds1307_read_block_data;
939                 ds1307->write_block_data = ds1307_write_block_data;
940         }
941 
942         switch (ds1307->type) {
943         case ds_1337:
944         case ds_1339:
945         case ds_3231:
946                 /* get registers that the "rtc" read below won't read... */
947                 tmp = ds1307->read_block_data(ds1307->client,
948                                 DS1337_REG_CONTROL, 2, buf);
949                 if (tmp != 2) {
950                         dev_dbg(&client->dev, "read error %d\n", tmp);
951                         err = -EIO;
952                         goto exit;
953                 }
954 
955                 /* oscillator off?  turn it on, so clock can tick. */
956                 if (ds1307->regs[0] & DS1337_BIT_nEOSC)
957                         ds1307->regs[0] &= ~DS1337_BIT_nEOSC;
958 
959                 /*
960                  * Using IRQ?  Disable the square wave and both alarms.
961                  * For some variants, be sure alarms can trigger when we're
962                  * running on Vbackup (BBSQI/BBSQW)
963                  */
964                 if (ds1307->client->irq > 0 && chip->alarm) {
965                         INIT_WORK(&ds1307->work, ds1307_work);
966 
967                         ds1307->regs[0] |= DS1337_BIT_INTCN
968                                         | bbsqi_bitpos[ds1307->type];
969                         ds1307->regs[0] &= ~(DS1337_BIT_A2IE | DS1337_BIT_A1IE);
970 
971                         want_irq = true;
972                 }
973 
974                 i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL,
975                                                         ds1307->regs[0]);
976 
977                 /* oscillator fault?  clear flag, and warn */
978                 if (ds1307->regs[1] & DS1337_BIT_OSF) {
979                         i2c_smbus_write_byte_data(client, DS1337_REG_STATUS,
980                                 ds1307->regs[1] & ~DS1337_BIT_OSF);
981                         dev_warn(&client->dev, "SET TIME!\n");
982                 }
983                 break;
984 
985         case rx_8025:
986                 tmp = i2c_smbus_read_i2c_block_data(ds1307->client,
987                                 RX8025_REG_CTRL1 << 4 | 0x08, 2, buf);
988                 if (tmp != 2) {
989                         dev_dbg(&client->dev, "read error %d\n", tmp);
990                         err = -EIO;
991                         goto exit;
992                 }
993 
994                 /* oscillator off?  turn it on, so clock can tick. */
995                 if (!(ds1307->regs[1] & RX8025_BIT_XST)) {
996                         ds1307->regs[1] |= RX8025_BIT_XST;
997                         i2c_smbus_write_byte_data(client,
998                                                   RX8025_REG_CTRL2 << 4 | 0x08,
999                                                   ds1307->regs[1]);
1000                         dev_warn(&client->dev,
1001                                  "oscillator stop detected - SET TIME!\n");
1002                 }
1003 
1004                 if (ds1307->regs[1] & RX8025_BIT_PON) {
1005                         ds1307->regs[1] &= ~RX8025_BIT_PON;
1006                         i2c_smbus_write_byte_data(client,
1007                                                   RX8025_REG_CTRL2 << 4 | 0x08,
1008                                                   ds1307->regs[1]);
1009                         dev_warn(&client->dev, "power-on detected\n");
1010                 }
1011 
1012                 if (ds1307->regs[1] & RX8025_BIT_VDET) {
1013                         ds1307->regs[1] &= ~RX8025_BIT_VDET;
1014                         i2c_smbus_write_byte_data(client,
1015                                                   RX8025_REG_CTRL2 << 4 | 0x08,
1016                                                   ds1307->regs[1]);
1017                         dev_warn(&client->dev, "voltage drop detected\n");
1018                 }
1019 
1020                 /* make sure we are running in 24hour mode */
1021                 if (!(ds1307->regs[0] & RX8025_BIT_2412)) {
1022                         u8 hour;
1023 
1024                         /* switch to 24 hour mode */
1025                         i2c_smbus_write_byte_data(client,
1026                                                   RX8025_REG_CTRL1 << 4 | 0x08,
1027                                                   ds1307->regs[0] |
1028                                                   RX8025_BIT_2412);
1029 
1030                         tmp = i2c_smbus_read_i2c_block_data(ds1307->client,
1031                                         RX8025_REG_CTRL1 << 4 | 0x08, 2, buf);
1032                         if (tmp != 2) {
1033                                 dev_dbg(&client->dev, "read error %d\n", tmp);
1034                                 err = -EIO;
1035                                 goto exit;
1036                         }
1037 
1038                         /* correct hour */
1039                         hour = bcd2bin(ds1307->regs[DS1307_REG_HOUR]);
1040                         if (hour == 12)
1041                                 hour = 0;
1042                         if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
1043                                 hour += 12;
1044 
1045                         i2c_smbus_write_byte_data(client,
1046                                                   DS1307_REG_HOUR << 4 | 0x08,
1047                                                   hour);
1048                 }
1049                 break;
1050         case ds_1388:
1051                 ds1307->offset = 1; /* Seconds starts at 1 */
1052                 break;
1053         case mcp794xx:
1054                 rtc_ops = &mcp794xx_rtc_ops;
1055                 if (ds1307->client->irq > 0 && chip->alarm) {
1056                         INIT_WORK(&ds1307->work, mcp794xx_work);
1057                         want_irq = true;
1058                 }
1059                 break;
1060         default:
1061                 break;
1062         }
1063 
1064 read_rtc:
1065         /* read RTC registers */
1066         tmp = ds1307->read_block_data(ds1307->client, ds1307->offset, 8, buf);
1067         if (tmp != 8) {
1068                 dev_dbg(&client->dev, "read error %d\n", tmp);
1069                 err = -EIO;
1070                 goto exit;
1071         }
1072 
1073         /*
1074          * minimal sanity checking; some chips (like DS1340) don't
1075          * specify the extra bits as must-be-zero, but there are
1076          * still a few values that are clearly out-of-range.
1077          */
1078         tmp = ds1307->regs[DS1307_REG_SECS];
1079         switch (ds1307->type) {
1080         case ds_1307:
1081         case m41t00:
1082                 /* clock halted?  turn it on, so clock can tick. */
1083                 if (tmp & DS1307_BIT_CH) {
1084                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
1085                         dev_warn(&client->dev, "SET TIME!\n");
1086                         goto read_rtc;
1087                 }
1088                 break;
1089         case ds_1338:
1090                 /* clock halted?  turn it on, so clock can tick. */
1091                 if (tmp & DS1307_BIT_CH)
1092                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
1093 
1094                 /* oscillator fault?  clear flag, and warn */
1095                 if (ds1307->regs[DS1307_REG_CONTROL] & DS1338_BIT_OSF) {
1096                         i2c_smbus_write_byte_data(client, DS1307_REG_CONTROL,
1097                                         ds1307->regs[DS1307_REG_CONTROL]
1098                                         & ~DS1338_BIT_OSF);
1099                         dev_warn(&client->dev, "SET TIME!\n");
1100                         goto read_rtc;
1101                 }
1102                 break;
1103         case ds_1340:
1104                 /* clock halted?  turn it on, so clock can tick. */
1105                 if (tmp & DS1340_BIT_nEOSC)
1106                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
1107 
1108                 tmp = i2c_smbus_read_byte_data(client, DS1340_REG_FLAG);
1109                 if (tmp < 0) {
1110                         dev_dbg(&client->dev, "read error %d\n", tmp);
1111                         err = -EIO;
1112                         goto exit;
1113                 }
1114 
1115                 /* oscillator fault?  clear flag, and warn */
1116                 if (tmp & DS1340_BIT_OSF) {
1117                         i2c_smbus_write_byte_data(client, DS1340_REG_FLAG, 0);
1118                         dev_warn(&client->dev, "SET TIME!\n");
1119                 }
1120                 break;
1121         case mcp794xx:
1122                 /* make sure that the backup battery is enabled */
1123                 if (!(ds1307->regs[DS1307_REG_WDAY] & MCP794XX_BIT_VBATEN)) {
1124                         i2c_smbus_write_byte_data(client, DS1307_REG_WDAY,
1125                                         ds1307->regs[DS1307_REG_WDAY]
1126                                         | MCP794XX_BIT_VBATEN);
1127                 }
1128 
1129                 /* clock halted?  turn it on, so clock can tick. */
1130                 if (!(tmp & MCP794XX_BIT_ST)) {
1131                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS,
1132                                         MCP794XX_BIT_ST);
1133                         dev_warn(&client->dev, "SET TIME!\n");
1134                         goto read_rtc;
1135                 }
1136 
1137                 break;
1138         default:
1139                 break;
1140         }
1141 
1142         tmp = ds1307->regs[DS1307_REG_HOUR];
1143         switch (ds1307->type) {
1144         case ds_1340:
1145         case m41t00:
1146                 /*
1147                  * NOTE: ignores century bits; fix before deploying
1148                  * systems that will run through year 2100.
1149                  */
1150                 break;
1151         case rx_8025:
1152                 break;
1153         default:
1154                 if (!(tmp & DS1307_BIT_12HR))
1155                         break;
1156 
1157                 /*
1158                  * Be sure we're in 24 hour mode.  Multi-master systems
1159                  * take note...
1160                  */
1161                 tmp = bcd2bin(tmp & 0x1f);
1162                 if (tmp == 12)
1163                         tmp = 0;
1164                 if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
1165                         tmp += 12;
1166                 i2c_smbus_write_byte_data(client,
1167                                 ds1307->offset + DS1307_REG_HOUR,
1168                                 bin2bcd(tmp));
1169         }
1170 
1171         device_set_wakeup_capable(&client->dev, want_irq);
1172         ds1307->rtc = devm_rtc_device_register(&client->dev, client->name,
1173                                 rtc_ops, THIS_MODULE);
1174         if (IS_ERR(ds1307->rtc)) {
1175                 return PTR_ERR(ds1307->rtc);
1176         }
1177 
1178         if (want_irq) {
1179                 err = request_irq(client->irq, ds1307_irq, IRQF_SHARED,
1180                           ds1307->rtc->name, client);
1181                 if (err) {
1182                         client->irq = 0;
1183                         dev_err(&client->dev, "unable to request IRQ!\n");
1184                 } else {
1185 
1186                         set_bit(HAS_ALARM, &ds1307->flags);
1187                         dev_dbg(&client->dev, "got IRQ %d\n", client->irq);
1188                 }
1189         }
1190 
1191         if (chip->nvram_size) {
1192 
1193                 ds1307->nvram = devm_kzalloc(&client->dev,
1194                                         sizeof(struct bin_attribute),
1195                                         GFP_KERNEL);
1196                 if (!ds1307->nvram) {
1197                         dev_err(&client->dev, "cannot allocate memory for nvram sysfs\n");
1198                 } else {
1199 
1200                         ds1307->nvram->attr.name = "nvram";
1201                         ds1307->nvram->attr.mode = S_IRUGO | S_IWUSR;
1202 
1203                         sysfs_bin_attr_init(ds1307->nvram);
1204 
1205                         ds1307->nvram->read = ds1307_nvram_read;
1206                         ds1307->nvram->write = ds1307_nvram_write;
1207                         ds1307->nvram->size = chip->nvram_size;
1208                         ds1307->nvram_offset = chip->nvram_offset;
1209 
1210                         err = sysfs_create_bin_file(&client->dev.kobj,
1211                                                     ds1307->nvram);
1212                         if (err) {
1213                                 dev_err(&client->dev,
1214                                         "unable to create sysfs file: %s\n",
1215                                         ds1307->nvram->attr.name);
1216                         } else {
1217                                 set_bit(HAS_NVRAM, &ds1307->flags);
1218                                 dev_info(&client->dev, "%zu bytes nvram\n",
1219                                          ds1307->nvram->size);
1220                         }
1221                 }
1222         }
1223 
1224         return 0;
1225 
1226 exit:
1227         return err;
1228 }
1229 
1230 static int ds1307_remove(struct i2c_client *client)
1231 {
1232         struct ds1307 *ds1307 = i2c_get_clientdata(client);
1233 
1234         if (test_and_clear_bit(HAS_ALARM, &ds1307->flags)) {
1235                 free_irq(client->irq, client);
1236                 cancel_work_sync(&ds1307->work);
1237         }
1238 
1239         if (test_and_clear_bit(HAS_NVRAM, &ds1307->flags))
1240                 sysfs_remove_bin_file(&client->dev.kobj, ds1307->nvram);
1241 
1242         return 0;
1243 }
1244 
1245 static struct i2c_driver ds1307_driver = {
1246         .driver = {
1247                 .name   = "rtc-ds1307",
1248                 .owner  = THIS_MODULE,
1249         },
1250         .probe          = ds1307_probe,
1251         .remove         = ds1307_remove,
1252         .id_table       = ds1307_id,
1253 };
1254 
1255 module_i2c_driver(ds1307_driver);
1256 
1257 MODULE_DESCRIPTION("RTC driver for DS1307 and similar chips");
1258 MODULE_LICENSE("GPL");
1259 

This page was automatically generated by LXR 0.3.1 (source).  •  Linux is a registered trademark of Linus Torvalds  •  Contact us