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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/bcd.h>
 15 #include <linux/i2c.h>
 16 #include <linux/init.h>
 17 #include <linux/module.h>
 18 #include <linux/rtc/ds1307.h>
 19 #include <linux/rtc.h>
 20 #include <linux/slab.h>
 21 #include <linux/string.h>
 22 #include <linux/hwmon.h>
 23 #include <linux/hwmon-sysfs.h>
 24 #include <linux/clk-provider.h>
 25 
 26 /*
 27  * We can't determine type by probing, but if we expect pre-Linux code
 28  * to have set the chip up as a clock (turning on the oscillator and
 29  * setting the date and time), Linux can ignore the non-clock features.
 30  * That's a natural job for a factory or repair bench.
 31  */
 32 enum ds_type {
 33         ds_1307,
 34         ds_1337,
 35         ds_1338,
 36         ds_1339,
 37         ds_1340,
 38         ds_1388,
 39         ds_3231,
 40         m41t00,
 41         mcp794xx,
 42         rx_8025,
 43         last_ds_type /* always last */
 44         /* rs5c372 too?  different address... */
 45 };
 46 
 47 
 48 /* RTC registers don't differ much, except for the century flag */
 49 #define DS1307_REG_SECS         0x00    /* 00-59 */
 50 #       define DS1307_BIT_CH            0x80
 51 #       define DS1340_BIT_nEOSC         0x80
 52 #       define MCP794XX_BIT_ST          0x80
 53 #define DS1307_REG_MIN          0x01    /* 00-59 */
 54 #define DS1307_REG_HOUR         0x02    /* 00-23, or 1-12{am,pm} */
 55 #       define DS1307_BIT_12HR          0x40    /* in REG_HOUR */
 56 #       define DS1307_BIT_PM            0x20    /* in REG_HOUR */
 57 #       define DS1340_BIT_CENTURY_EN    0x80    /* in REG_HOUR */
 58 #       define DS1340_BIT_CENTURY       0x40    /* in REG_HOUR */
 59 #define DS1307_REG_WDAY         0x03    /* 01-07 */
 60 #       define MCP794XX_BIT_VBATEN      0x08
 61 #define DS1307_REG_MDAY         0x04    /* 01-31 */
 62 #define DS1307_REG_MONTH        0x05    /* 01-12 */
 63 #       define DS1337_BIT_CENTURY       0x80    /* in REG_MONTH */
 64 #define DS1307_REG_YEAR         0x06    /* 00-99 */
 65 
 66 /*
 67  * Other registers (control, status, alarms, trickle charge, NVRAM, etc)
 68  * start at 7, and they differ a LOT. Only control and status matter for
 69  * basic RTC date and time functionality; be careful using them.
 70  */
 71 #define DS1307_REG_CONTROL      0x07            /* or ds1338 */
 72 #       define DS1307_BIT_OUT           0x80
 73 #       define DS1338_BIT_OSF           0x20
 74 #       define DS1307_BIT_SQWE          0x10
 75 #       define DS1307_BIT_RS1           0x02
 76 #       define DS1307_BIT_RS0           0x01
 77 #define DS1337_REG_CONTROL      0x0e
 78 #       define DS1337_BIT_nEOSC         0x80
 79 #       define DS1339_BIT_BBSQI         0x20
 80 #       define DS3231_BIT_BBSQW         0x40 /* same as BBSQI */
 81 #       define DS1337_BIT_RS2           0x10
 82 #       define DS1337_BIT_RS1           0x08
 83 #       define DS1337_BIT_INTCN         0x04
 84 #       define DS1337_BIT_A2IE          0x02
 85 #       define DS1337_BIT_A1IE          0x01
 86 #define DS1340_REG_CONTROL      0x07
 87 #       define DS1340_BIT_OUT           0x80
 88 #       define DS1340_BIT_FT            0x40
 89 #       define DS1340_BIT_CALIB_SIGN    0x20
 90 #       define DS1340_M_CALIBRATION     0x1f
 91 #define DS1340_REG_FLAG         0x09
 92 #       define DS1340_BIT_OSF           0x80
 93 #define DS1337_REG_STATUS       0x0f
 94 #       define DS1337_BIT_OSF           0x80
 95 #       define DS3231_BIT_EN32KHZ       0x08
 96 #       define DS1337_BIT_A2I           0x02
 97 #       define DS1337_BIT_A1I           0x01
 98 #define DS1339_REG_ALARM1_SECS  0x07
 99 
100 #define DS13XX_TRICKLE_CHARGER_MAGIC    0xa0
101 
102 #define RX8025_REG_CTRL1        0x0e
103 #       define RX8025_BIT_2412          0x20
104 #define RX8025_REG_CTRL2        0x0f
105 #       define RX8025_BIT_PON           0x10
106 #       define RX8025_BIT_VDET          0x40
107 #       define RX8025_BIT_XST           0x20
108 
109 
110 struct ds1307 {
111         u8                      offset; /* register's offset */
112         u8                      regs[11];
113         u16                     nvram_offset;
114         struct bin_attribute    *nvram;
115         enum ds_type            type;
116         unsigned long           flags;
117 #define HAS_NVRAM       0               /* bit 0 == sysfs file active */
118 #define HAS_ALARM       1               /* bit 1 == irq claimed */
119         struct i2c_client       *client;
120         struct rtc_device       *rtc;
121         s32 (*read_block_data)(const struct i2c_client *client, u8 command,
122                                u8 length, u8 *values);
123         s32 (*write_block_data)(const struct i2c_client *client, u8 command,
124                                 u8 length, const u8 *values);
125 #ifdef CONFIG_COMMON_CLK
126         struct clk_hw           clks[2];
127 #endif
128 };
129 
130 struct chip_desc {
131         unsigned                alarm:1;
132         u16                     nvram_offset;
133         u16                     nvram_size;
134         u16                     trickle_charger_reg;
135         u8                      trickle_charger_setup;
136         u8                      (*do_trickle_setup)(struct i2c_client *, uint32_t, bool);
137 };
138 
139 static u8 do_trickle_setup_ds1339(struct i2c_client *,
140                                   uint32_t ohms, bool diode);
141 
142 static struct chip_desc chips[last_ds_type] = {
143         [ds_1307] = {
144                 .nvram_offset   = 8,
145                 .nvram_size     = 56,
146         },
147         [ds_1337] = {
148                 .alarm          = 1,
149         },
150         [ds_1338] = {
151                 .nvram_offset   = 8,
152                 .nvram_size     = 56,
153         },
154         [ds_1339] = {
155                 .alarm          = 1,
156                 .trickle_charger_reg = 0x10,
157                 .do_trickle_setup = &do_trickle_setup_ds1339,
158         },
159         [ds_1340] = {
160                 .trickle_charger_reg = 0x08,
161         },
162         [ds_1388] = {
163                 .trickle_charger_reg = 0x0a,
164         },
165         [ds_3231] = {
166                 .alarm          = 1,
167         },
168         [mcp794xx] = {
169                 .alarm          = 1,
170                 /* this is battery backed SRAM */
171                 .nvram_offset   = 0x20,
172                 .nvram_size     = 0x40,
173         },
174 };
175 
176 static const struct i2c_device_id ds1307_id[] = {
177         { "ds1307", ds_1307 },
178         { "ds1337", ds_1337 },
179         { "ds1338", ds_1338 },
180         { "ds1339", ds_1339 },
181         { "ds1388", ds_1388 },
182         { "ds1340", ds_1340 },
183         { "ds3231", ds_3231 },
184         { "m41t00", m41t00 },
185         { "mcp7940x", mcp794xx },
186         { "mcp7941x", mcp794xx },
187         { "pt7c4338", ds_1307 },
188         { "rx8025", rx_8025 },
189         { }
190 };
191 MODULE_DEVICE_TABLE(i2c, ds1307_id);
192 
193 /*----------------------------------------------------------------------*/
194 
195 #define BLOCK_DATA_MAX_TRIES 10
196 
197 static s32 ds1307_read_block_data_once(const struct i2c_client *client,
198                                        u8 command, u8 length, u8 *values)
199 {
200         s32 i, data;
201 
202         for (i = 0; i < length; i++) {
203                 data = i2c_smbus_read_byte_data(client, command + i);
204                 if (data < 0)
205                         return data;
206                 values[i] = data;
207         }
208         return i;
209 }
210 
211 static s32 ds1307_read_block_data(const struct i2c_client *client, u8 command,
212                                   u8 length, u8 *values)
213 {
214         u8 oldvalues[255];
215         s32 ret;
216         int tries = 0;
217 
218         dev_dbg(&client->dev, "ds1307_read_block_data (length=%d)\n", length);
219         ret = ds1307_read_block_data_once(client, command, length, values);
220         if (ret < 0)
221                 return ret;
222         do {
223                 if (++tries > BLOCK_DATA_MAX_TRIES) {
224                         dev_err(&client->dev,
225                                 "ds1307_read_block_data failed\n");
226                         return -EIO;
227                 }
228                 memcpy(oldvalues, values, length);
229                 ret = ds1307_read_block_data_once(client, command, length,
230                                                   values);
231                 if (ret < 0)
232                         return ret;
233         } while (memcmp(oldvalues, values, length));
234         return length;
235 }
236 
237 static s32 ds1307_write_block_data(const struct i2c_client *client, u8 command,
238                                    u8 length, const u8 *values)
239 {
240         u8 currvalues[255];
241         int tries = 0;
242 
243         dev_dbg(&client->dev, "ds1307_write_block_data (length=%d)\n", length);
244         do {
245                 s32 i, ret;
246 
247                 if (++tries > BLOCK_DATA_MAX_TRIES) {
248                         dev_err(&client->dev,
249                                 "ds1307_write_block_data failed\n");
250                         return -EIO;
251                 }
252                 for (i = 0; i < length; i++) {
253                         ret = i2c_smbus_write_byte_data(client, command + i,
254                                                         values[i]);
255                         if (ret < 0)
256                                 return ret;
257                 }
258                 ret = ds1307_read_block_data_once(client, command, length,
259                                                   currvalues);
260                 if (ret < 0)
261                         return ret;
262         } while (memcmp(currvalues, values, length));
263         return length;
264 }
265 
266 /*----------------------------------------------------------------------*/
267 
268 /* These RTC devices are not designed to be connected to a SMbus adapter.
269    SMbus limits block operations length to 32 bytes, whereas it's not
270    limited on I2C buses. As a result, accesses may exceed 32 bytes;
271    in that case, split them into smaller blocks */
272 
273 static s32 ds1307_native_smbus_write_block_data(const struct i2c_client *client,
274                                 u8 command, u8 length, const u8 *values)
275 {
276         u8 suboffset = 0;
277 
278         if (length <= I2C_SMBUS_BLOCK_MAX) {
279                 s32 retval = i2c_smbus_write_i2c_block_data(client,
280                                         command, length, values);
281                 if (retval < 0)
282                         return retval;
283                 return length;
284         }
285 
286         while (suboffset < length) {
287                 s32 retval = i2c_smbus_write_i2c_block_data(client,
288                                 command + suboffset,
289                                 min(I2C_SMBUS_BLOCK_MAX, length - suboffset),
290                                 values + suboffset);
291                 if (retval < 0)
292                         return retval;
293 
294                 suboffset += I2C_SMBUS_BLOCK_MAX;
295         }
296         return length;
297 }
298 
299 static s32 ds1307_native_smbus_read_block_data(const struct i2c_client *client,
300                                 u8 command, u8 length, u8 *values)
301 {
302         u8 suboffset = 0;
303 
304         if (length <= I2C_SMBUS_BLOCK_MAX)
305                 return i2c_smbus_read_i2c_block_data(client,
306                                         command, length, values);
307 
308         while (suboffset < length) {
309                 s32 retval = i2c_smbus_read_i2c_block_data(client,
310                                 command + suboffset,
311                                 min(I2C_SMBUS_BLOCK_MAX, length - suboffset),
312                                 values + suboffset);
313                 if (retval < 0)
314                         return retval;
315 
316                 suboffset += I2C_SMBUS_BLOCK_MAX;
317         }
318         return length;
319 }
320 
321 /*----------------------------------------------------------------------*/
322 
323 /*
324  * The ds1337 and ds1339 both have two alarms, but we only use the first
325  * one (with a "seconds" field).  For ds1337 we expect nINTA is our alarm
326  * signal; ds1339 chips have only one alarm signal.
327  */
328 static irqreturn_t ds1307_irq(int irq, void *dev_id)
329 {
330         struct i2c_client       *client = dev_id;
331         struct ds1307           *ds1307 = i2c_get_clientdata(client);
332         struct mutex            *lock = &ds1307->rtc->ops_lock;
333         int                     stat, control;
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         mutex_unlock(lock);
356 
357         return IRQ_HANDLED;
358 }
359 
360 /*----------------------------------------------------------------------*/
361 
362 static int ds1307_get_time(struct device *dev, struct rtc_time *t)
363 {
364         struct ds1307   *ds1307 = dev_get_drvdata(dev);
365         int             tmp;
366 
367         /* read the RTC date and time registers all at once */
368         tmp = ds1307->read_block_data(ds1307->client,
369                 ds1307->offset, 7, ds1307->regs);
370         if (tmp != 7) {
371                 dev_err(dev, "%s error %d\n", "read", tmp);
372                 return -EIO;
373         }
374 
375         dev_dbg(dev, "%s: %7ph\n", "read", ds1307->regs);
376 
377         t->tm_sec = bcd2bin(ds1307->regs[DS1307_REG_SECS] & 0x7f);
378         t->tm_min = bcd2bin(ds1307->regs[DS1307_REG_MIN] & 0x7f);
379         tmp = ds1307->regs[DS1307_REG_HOUR] & 0x3f;
380         t->tm_hour = bcd2bin(tmp);
381         t->tm_wday = bcd2bin(ds1307->regs[DS1307_REG_WDAY] & 0x07) - 1;
382         t->tm_mday = bcd2bin(ds1307->regs[DS1307_REG_MDAY] & 0x3f);
383         tmp = ds1307->regs[DS1307_REG_MONTH] & 0x1f;
384         t->tm_mon = bcd2bin(tmp) - 1;
385 
386         /* assume 20YY not 19YY, and ignore DS1337_BIT_CENTURY */
387         t->tm_year = bcd2bin(ds1307->regs[DS1307_REG_YEAR]) + 100;
388 
389         dev_dbg(dev, "%s secs=%d, mins=%d, "
390                 "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
391                 "read", t->tm_sec, t->tm_min,
392                 t->tm_hour, t->tm_mday,
393                 t->tm_mon, t->tm_year, t->tm_wday);
394 
395         /* initial clock setting can be undefined */
396         return rtc_valid_tm(t);
397 }
398 
399 static int ds1307_set_time(struct device *dev, struct rtc_time *t)
400 {
401         struct ds1307   *ds1307 = dev_get_drvdata(dev);
402         int             result;
403         int             tmp;
404         u8              *buf = ds1307->regs;
405 
406         dev_dbg(dev, "%s secs=%d, mins=%d, "
407                 "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
408                 "write", t->tm_sec, t->tm_min,
409                 t->tm_hour, t->tm_mday,
410                 t->tm_mon, t->tm_year, t->tm_wday);
411 
412         buf[DS1307_REG_SECS] = bin2bcd(t->tm_sec);
413         buf[DS1307_REG_MIN] = bin2bcd(t->tm_min);
414         buf[DS1307_REG_HOUR] = bin2bcd(t->tm_hour);
415         buf[DS1307_REG_WDAY] = bin2bcd(t->tm_wday + 1);
416         buf[DS1307_REG_MDAY] = bin2bcd(t->tm_mday);
417         buf[DS1307_REG_MONTH] = bin2bcd(t->tm_mon + 1);
418 
419         /* assume 20YY not 19YY */
420         tmp = t->tm_year - 100;
421         buf[DS1307_REG_YEAR] = bin2bcd(tmp);
422 
423         switch (ds1307->type) {
424         case ds_1337:
425         case ds_1339:
426         case ds_3231:
427                 buf[DS1307_REG_MONTH] |= DS1337_BIT_CENTURY;
428                 break;
429         case ds_1340:
430                 buf[DS1307_REG_HOUR] |= DS1340_BIT_CENTURY_EN
431                                 | DS1340_BIT_CENTURY;
432                 break;
433         case mcp794xx:
434                 /*
435                  * these bits were cleared when preparing the date/time
436                  * values and need to be set again before writing the
437                  * buffer out to the device.
438                  */
439                 buf[DS1307_REG_SECS] |= MCP794XX_BIT_ST;
440                 buf[DS1307_REG_WDAY] |= MCP794XX_BIT_VBATEN;
441                 break;
442         default:
443                 break;
444         }
445 
446         dev_dbg(dev, "%s: %7ph\n", "write", buf);
447 
448         result = ds1307->write_block_data(ds1307->client,
449                 ds1307->offset, 7, buf);
450         if (result < 0) {
451                 dev_err(dev, "%s error %d\n", "write", result);
452                 return result;
453         }
454         return 0;
455 }
456 
457 static int ds1337_read_alarm(struct device *dev, struct rtc_wkalrm *t)
458 {
459         struct i2c_client       *client = to_i2c_client(dev);
460         struct ds1307           *ds1307 = i2c_get_clientdata(client);
461         int                     ret;
462 
463         if (!test_bit(HAS_ALARM, &ds1307->flags))
464                 return -EINVAL;
465 
466         /* read all ALARM1, ALARM2, and status registers at once */
467         ret = ds1307->read_block_data(client,
468                         DS1339_REG_ALARM1_SECS, 9, ds1307->regs);
469         if (ret != 9) {
470                 dev_err(dev, "%s error %d\n", "alarm read", ret);
471                 return -EIO;
472         }
473 
474         dev_dbg(dev, "%s: %4ph, %3ph, %2ph\n", "alarm read",
475                 &ds1307->regs[0], &ds1307->regs[4], &ds1307->regs[7]);
476 
477         /*
478          * report alarm time (ALARM1); assume 24 hour and day-of-month modes,
479          * and that all four fields are checked matches
480          */
481         t->time.tm_sec = bcd2bin(ds1307->regs[0] & 0x7f);
482         t->time.tm_min = bcd2bin(ds1307->regs[1] & 0x7f);
483         t->time.tm_hour = bcd2bin(ds1307->regs[2] & 0x3f);
484         t->time.tm_mday = bcd2bin(ds1307->regs[3] & 0x3f);
485         t->time.tm_mon = -1;
486         t->time.tm_year = -1;
487         t->time.tm_wday = -1;
488         t->time.tm_yday = -1;
489         t->time.tm_isdst = -1;
490 
491         /* ... and status */
492         t->enabled = !!(ds1307->regs[7] & DS1337_BIT_A1IE);
493         t->pending = !!(ds1307->regs[8] & DS1337_BIT_A1I);
494 
495         dev_dbg(dev, "%s secs=%d, mins=%d, "
496                 "hours=%d, mday=%d, enabled=%d, pending=%d\n",
497                 "alarm read", t->time.tm_sec, t->time.tm_min,
498                 t->time.tm_hour, t->time.tm_mday,
499                 t->enabled, t->pending);
500 
501         return 0;
502 }
503 
504 static int ds1337_set_alarm(struct device *dev, struct rtc_wkalrm *t)
505 {
506         struct i2c_client       *client = to_i2c_client(dev);
507         struct ds1307           *ds1307 = i2c_get_clientdata(client);
508         unsigned char           *buf = ds1307->regs;
509         u8                      control, status;
510         int                     ret;
511 
512         if (!test_bit(HAS_ALARM, &ds1307->flags))
513                 return -EINVAL;
514 
515         dev_dbg(dev, "%s secs=%d, mins=%d, "
516                 "hours=%d, mday=%d, enabled=%d, pending=%d\n",
517                 "alarm set", t->time.tm_sec, t->time.tm_min,
518                 t->time.tm_hour, t->time.tm_mday,
519                 t->enabled, t->pending);
520 
521         /* read current status of both alarms and the chip */
522         ret = ds1307->read_block_data(client,
523                         DS1339_REG_ALARM1_SECS, 9, buf);
524         if (ret != 9) {
525                 dev_err(dev, "%s error %d\n", "alarm write", ret);
526                 return -EIO;
527         }
528         control = ds1307->regs[7];
529         status = ds1307->regs[8];
530 
531         dev_dbg(dev, "%s: %4ph, %3ph, %02x %02x\n", "alarm set (old status)",
532                 &ds1307->regs[0], &ds1307->regs[4], control, status);
533 
534         /* set ALARM1, using 24 hour and day-of-month modes */
535         buf[0] = bin2bcd(t->time.tm_sec);
536         buf[1] = bin2bcd(t->time.tm_min);
537         buf[2] = bin2bcd(t->time.tm_hour);
538         buf[3] = bin2bcd(t->time.tm_mday);
539 
540         /* set ALARM2 to non-garbage */
541         buf[4] = 0;
542         buf[5] = 0;
543         buf[6] = 0;
544 
545         /* disable alarms */
546         buf[7] = control & ~(DS1337_BIT_A1IE | DS1337_BIT_A2IE);
547         buf[8] = status & ~(DS1337_BIT_A1I | DS1337_BIT_A2I);
548 
549         ret = ds1307->write_block_data(client,
550                         DS1339_REG_ALARM1_SECS, 9, buf);
551         if (ret < 0) {
552                 dev_err(dev, "can't set alarm time\n");
553                 return ret;
554         }
555 
556         /* optionally enable ALARM1 */
557         if (t->enabled) {
558                 dev_dbg(dev, "alarm IRQ armed\n");
559                 buf[7] |= DS1337_BIT_A1IE;      /* only ALARM1 is used */
560                 i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL, buf[7]);
561         }
562 
563         return 0;
564 }
565 
566 static int ds1307_alarm_irq_enable(struct device *dev, unsigned int enabled)
567 {
568         struct i2c_client       *client = to_i2c_client(dev);
569         struct ds1307           *ds1307 = i2c_get_clientdata(client);
570         int                     ret;
571 
572         if (!test_bit(HAS_ALARM, &ds1307->flags))
573                 return -ENOTTY;
574 
575         ret = i2c_smbus_read_byte_data(client, DS1337_REG_CONTROL);
576         if (ret < 0)
577                 return ret;
578 
579         if (enabled)
580                 ret |= DS1337_BIT_A1IE;
581         else
582                 ret &= ~DS1337_BIT_A1IE;
583 
584         ret = i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL, ret);
585         if (ret < 0)
586                 return ret;
587 
588         return 0;
589 }
590 
591 static const struct rtc_class_ops ds13xx_rtc_ops = {
592         .read_time      = ds1307_get_time,
593         .set_time       = ds1307_set_time,
594         .read_alarm     = ds1337_read_alarm,
595         .set_alarm      = ds1337_set_alarm,
596         .alarm_irq_enable = ds1307_alarm_irq_enable,
597 };
598 
599 /*----------------------------------------------------------------------*/
600 
601 /*
602  * Alarm support for mcp794xx devices.
603  */
604 
605 #define MCP794XX_REG_CONTROL            0x07
606 #       define MCP794XX_BIT_ALM0_EN     0x10
607 #       define MCP794XX_BIT_ALM1_EN     0x20
608 #define MCP794XX_REG_ALARM0_BASE        0x0a
609 #define MCP794XX_REG_ALARM0_CTRL        0x0d
610 #define MCP794XX_REG_ALARM1_BASE        0x11
611 #define MCP794XX_REG_ALARM1_CTRL        0x14
612 #       define MCP794XX_BIT_ALMX_IF     (1 << 3)
613 #       define MCP794XX_BIT_ALMX_C0     (1 << 4)
614 #       define MCP794XX_BIT_ALMX_C1     (1 << 5)
615 #       define MCP794XX_BIT_ALMX_C2     (1 << 6)
616 #       define MCP794XX_BIT_ALMX_POL    (1 << 7)
617 #       define MCP794XX_MSK_ALMX_MATCH  (MCP794XX_BIT_ALMX_C0 | \
618                                          MCP794XX_BIT_ALMX_C1 | \
619                                          MCP794XX_BIT_ALMX_C2)
620 
621 static irqreturn_t mcp794xx_irq(int irq, void *dev_id)
622 {
623         struct i2c_client       *client = dev_id;
624         struct ds1307           *ds1307 = i2c_get_clientdata(client);
625         struct mutex            *lock = &ds1307->rtc->ops_lock;
626         int reg, ret;
627 
628         mutex_lock(lock);
629 
630         /* Check and clear alarm 0 interrupt flag. */
631         reg = i2c_smbus_read_byte_data(client, MCP794XX_REG_ALARM0_CTRL);
632         if (reg < 0)
633                 goto out;
634         if (!(reg & MCP794XX_BIT_ALMX_IF))
635                 goto out;
636         reg &= ~MCP794XX_BIT_ALMX_IF;
637         ret = i2c_smbus_write_byte_data(client, MCP794XX_REG_ALARM0_CTRL, reg);
638         if (ret < 0)
639                 goto out;
640 
641         /* Disable alarm 0. */
642         reg = i2c_smbus_read_byte_data(client, MCP794XX_REG_CONTROL);
643         if (reg < 0)
644                 goto out;
645         reg &= ~MCP794XX_BIT_ALM0_EN;
646         ret = i2c_smbus_write_byte_data(client, MCP794XX_REG_CONTROL, reg);
647         if (ret < 0)
648                 goto out;
649 
650         rtc_update_irq(ds1307->rtc, 1, RTC_AF | RTC_IRQF);
651 
652 out:
653         mutex_unlock(lock);
654 
655         return IRQ_HANDLED;
656 }
657 
658 static int mcp794xx_read_alarm(struct device *dev, struct rtc_wkalrm *t)
659 {
660         struct i2c_client *client = to_i2c_client(dev);
661         struct ds1307 *ds1307 = i2c_get_clientdata(client);
662         u8 *regs = ds1307->regs;
663         int ret;
664 
665         if (!test_bit(HAS_ALARM, &ds1307->flags))
666                 return -EINVAL;
667 
668         /* Read control and alarm 0 registers. */
669         ret = ds1307->read_block_data(client, MCP794XX_REG_CONTROL, 10, regs);
670         if (ret < 0)
671                 return ret;
672 
673         t->enabled = !!(regs[0] & MCP794XX_BIT_ALM0_EN);
674 
675         /* Report alarm 0 time assuming 24-hour and day-of-month modes. */
676         t->time.tm_sec = bcd2bin(ds1307->regs[3] & 0x7f);
677         t->time.tm_min = bcd2bin(ds1307->regs[4] & 0x7f);
678         t->time.tm_hour = bcd2bin(ds1307->regs[5] & 0x3f);
679         t->time.tm_wday = bcd2bin(ds1307->regs[6] & 0x7) - 1;
680         t->time.tm_mday = bcd2bin(ds1307->regs[7] & 0x3f);
681         t->time.tm_mon = bcd2bin(ds1307->regs[8] & 0x1f) - 1;
682         t->time.tm_year = -1;
683         t->time.tm_yday = -1;
684         t->time.tm_isdst = -1;
685 
686         dev_dbg(dev, "%s, sec=%d min=%d hour=%d wday=%d mday=%d mon=%d "
687                 "enabled=%d polarity=%d irq=%d match=%d\n", __func__,
688                 t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
689                 t->time.tm_wday, t->time.tm_mday, t->time.tm_mon, t->enabled,
690                 !!(ds1307->regs[6] & MCP794XX_BIT_ALMX_POL),
691                 !!(ds1307->regs[6] & MCP794XX_BIT_ALMX_IF),
692                 (ds1307->regs[6] & MCP794XX_MSK_ALMX_MATCH) >> 4);
693 
694         return 0;
695 }
696 
697 static int mcp794xx_set_alarm(struct device *dev, struct rtc_wkalrm *t)
698 {
699         struct i2c_client *client = to_i2c_client(dev);
700         struct ds1307 *ds1307 = i2c_get_clientdata(client);
701         unsigned char *regs = ds1307->regs;
702         int ret;
703 
704         if (!test_bit(HAS_ALARM, &ds1307->flags))
705                 return -EINVAL;
706 
707         dev_dbg(dev, "%s, sec=%d min=%d hour=%d wday=%d mday=%d mon=%d "
708                 "enabled=%d pending=%d\n", __func__,
709                 t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
710                 t->time.tm_wday, t->time.tm_mday, t->time.tm_mon,
711                 t->enabled, t->pending);
712 
713         /* Read control and alarm 0 registers. */
714         ret = ds1307->read_block_data(client, MCP794XX_REG_CONTROL, 10, regs);
715         if (ret < 0)
716                 return ret;
717 
718         /* Set alarm 0, using 24-hour and day-of-month modes. */
719         regs[3] = bin2bcd(t->time.tm_sec);
720         regs[4] = bin2bcd(t->time.tm_min);
721         regs[5] = bin2bcd(t->time.tm_hour);
722         regs[6] = bin2bcd(t->time.tm_wday + 1);
723         regs[7] = bin2bcd(t->time.tm_mday);
724         regs[8] = bin2bcd(t->time.tm_mon + 1);
725 
726         /* Clear the alarm 0 interrupt flag. */
727         regs[6] &= ~MCP794XX_BIT_ALMX_IF;
728         /* Set alarm match: second, minute, hour, day, date, month. */
729         regs[6] |= MCP794XX_MSK_ALMX_MATCH;
730         /* Disable interrupt. We will not enable until completely programmed */
731         regs[0] &= ~MCP794XX_BIT_ALM0_EN;
732 
733         ret = ds1307->write_block_data(client, MCP794XX_REG_CONTROL, 10, regs);
734         if (ret < 0)
735                 return ret;
736 
737         if (!t->enabled)
738                 return 0;
739         regs[0] |= MCP794XX_BIT_ALM0_EN;
740         return i2c_smbus_write_byte_data(client, MCP794XX_REG_CONTROL, regs[0]);
741 }
742 
743 static int mcp794xx_alarm_irq_enable(struct device *dev, unsigned int enabled)
744 {
745         struct i2c_client *client = to_i2c_client(dev);
746         struct ds1307 *ds1307 = i2c_get_clientdata(client);
747         int reg;
748 
749         if (!test_bit(HAS_ALARM, &ds1307->flags))
750                 return -EINVAL;
751 
752         reg = i2c_smbus_read_byte_data(client, MCP794XX_REG_CONTROL);
753         if (reg < 0)
754                 return reg;
755 
756         if (enabled)
757                 reg |= MCP794XX_BIT_ALM0_EN;
758         else
759                 reg &= ~MCP794XX_BIT_ALM0_EN;
760 
761         return i2c_smbus_write_byte_data(client, MCP794XX_REG_CONTROL, reg);
762 }
763 
764 static const struct rtc_class_ops mcp794xx_rtc_ops = {
765         .read_time      = ds1307_get_time,
766         .set_time       = ds1307_set_time,
767         .read_alarm     = mcp794xx_read_alarm,
768         .set_alarm      = mcp794xx_set_alarm,
769         .alarm_irq_enable = mcp794xx_alarm_irq_enable,
770 };
771 
772 /*----------------------------------------------------------------------*/
773 
774 static ssize_t
775 ds1307_nvram_read(struct file *filp, struct kobject *kobj,
776                 struct bin_attribute *attr,
777                 char *buf, loff_t off, size_t count)
778 {
779         struct i2c_client       *client;
780         struct ds1307           *ds1307;
781         int                     result;
782 
783         client = kobj_to_i2c_client(kobj);
784         ds1307 = i2c_get_clientdata(client);
785 
786         result = ds1307->read_block_data(client, ds1307->nvram_offset + off,
787                                                                 count, buf);
788         if (result < 0)
789                 dev_err(&client->dev, "%s error %d\n", "nvram read", result);
790         return result;
791 }
792 
793 static ssize_t
794 ds1307_nvram_write(struct file *filp, struct kobject *kobj,
795                 struct bin_attribute *attr,
796                 char *buf, loff_t off, size_t count)
797 {
798         struct i2c_client       *client;
799         struct ds1307           *ds1307;
800         int                     result;
801 
802         client = kobj_to_i2c_client(kobj);
803         ds1307 = i2c_get_clientdata(client);
804 
805         result = ds1307->write_block_data(client, ds1307->nvram_offset + off,
806                                                                 count, buf);
807         if (result < 0) {
808                 dev_err(&client->dev, "%s error %d\n", "nvram write", result);
809                 return result;
810         }
811         return count;
812 }
813 
814 
815 /*----------------------------------------------------------------------*/
816 
817 static u8 do_trickle_setup_ds1339(struct i2c_client *client,
818                                   uint32_t ohms, bool diode)
819 {
820         u8 setup = (diode) ? DS1307_TRICKLE_CHARGER_DIODE :
821                 DS1307_TRICKLE_CHARGER_NO_DIODE;
822 
823         switch (ohms) {
824         case 250:
825                 setup |= DS1307_TRICKLE_CHARGER_250_OHM;
826                 break;
827         case 2000:
828                 setup |= DS1307_TRICKLE_CHARGER_2K_OHM;
829                 break;
830         case 4000:
831                 setup |= DS1307_TRICKLE_CHARGER_4K_OHM;
832                 break;
833         default:
834                 dev_warn(&client->dev,
835                          "Unsupported ohm value %u in dt\n", ohms);
836                 return 0;
837         }
838         return setup;
839 }
840 
841 static void ds1307_trickle_of_init(struct i2c_client *client,
842                                    struct chip_desc *chip)
843 {
844         uint32_t ohms = 0;
845         bool diode = true;
846 
847         if (!chip->do_trickle_setup)
848                 goto out;
849         if (of_property_read_u32(client->dev.of_node, "trickle-resistor-ohms" , &ohms))
850                 goto out;
851         if (of_property_read_bool(client->dev.of_node, "trickle-diode-disable"))
852                 diode = false;
853         chip->trickle_charger_setup = chip->do_trickle_setup(client,
854                                                              ohms, diode);
855 out:
856         return;
857 }
858 
859 /*----------------------------------------------------------------------*/
860 
861 #ifdef CONFIG_RTC_DRV_DS1307_HWMON
862 
863 /*
864  * Temperature sensor support for ds3231 devices.
865  */
866 
867 #define DS3231_REG_TEMPERATURE  0x11
868 
869 /*
870  * A user-initiated temperature conversion is not started by this function,
871  * so the temperature is updated once every 64 seconds.
872  */
873 static int ds3231_hwmon_read_temp(struct device *dev, s32 *mC)
874 {
875         struct ds1307 *ds1307 = dev_get_drvdata(dev);
876         u8 temp_buf[2];
877         s16 temp;
878         int ret;
879 
880         ret = ds1307->read_block_data(ds1307->client, DS3231_REG_TEMPERATURE,
881                                         sizeof(temp_buf), temp_buf);
882         if (ret < 0)
883                 return ret;
884         if (ret != sizeof(temp_buf))
885                 return -EIO;
886 
887         /*
888          * Temperature is represented as a 10-bit code with a resolution of
889          * 0.25 degree celsius and encoded in two's complement format.
890          */
891         temp = (temp_buf[0] << 8) | temp_buf[1];
892         temp >>= 6;
893         *mC = temp * 250;
894 
895         return 0;
896 }
897 
898 static ssize_t ds3231_hwmon_show_temp(struct device *dev,
899                                 struct device_attribute *attr, char *buf)
900 {
901         int ret;
902         s32 temp;
903 
904         ret = ds3231_hwmon_read_temp(dev, &temp);
905         if (ret)
906                 return ret;
907 
908         return sprintf(buf, "%d\n", temp);
909 }
910 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, ds3231_hwmon_show_temp,
911                         NULL, 0);
912 
913 static struct attribute *ds3231_hwmon_attrs[] = {
914         &sensor_dev_attr_temp1_input.dev_attr.attr,
915         NULL,
916 };
917 ATTRIBUTE_GROUPS(ds3231_hwmon);
918 
919 static void ds1307_hwmon_register(struct ds1307 *ds1307)
920 {
921         struct device *dev;
922 
923         if (ds1307->type != ds_3231)
924                 return;
925 
926         dev = devm_hwmon_device_register_with_groups(&ds1307->client->dev,
927                                                 ds1307->client->name,
928                                                 ds1307, ds3231_hwmon_groups);
929         if (IS_ERR(dev)) {
930                 dev_warn(&ds1307->client->dev,
931                         "unable to register hwmon device %ld\n", PTR_ERR(dev));
932         }
933 }
934 
935 #else
936 
937 static void ds1307_hwmon_register(struct ds1307 *ds1307)
938 {
939 }
940 
941 #endif /* CONFIG_RTC_DRV_DS1307_HWMON */
942 
943 /*----------------------------------------------------------------------*/
944 
945 /*
946  * Square-wave output support for DS3231
947  * Datasheet: https://datasheets.maximintegrated.com/en/ds/DS3231.pdf
948  */
949 #ifdef CONFIG_COMMON_CLK
950 
951 enum {
952         DS3231_CLK_SQW = 0,
953         DS3231_CLK_32KHZ,
954 };
955 
956 #define clk_sqw_to_ds1307(clk)  \
957         container_of(clk, struct ds1307, clks[DS3231_CLK_SQW])
958 #define clk_32khz_to_ds1307(clk)        \
959         container_of(clk, struct ds1307, clks[DS3231_CLK_32KHZ])
960 
961 static int ds3231_clk_sqw_rates[] = {
962         1,
963         1024,
964         4096,
965         8192,
966 };
967 
968 static int ds1337_write_control(struct ds1307 *ds1307, u8 mask, u8 value)
969 {
970         struct i2c_client *client = ds1307->client;
971         struct mutex *lock = &ds1307->rtc->ops_lock;
972         int control;
973         int ret;
974 
975         mutex_lock(lock);
976 
977         control = i2c_smbus_read_byte_data(client, DS1337_REG_CONTROL);
978         if (control < 0) {
979                 ret = control;
980                 goto out;
981         }
982 
983         control &= ~mask;
984         control |= value;
985 
986         ret = i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL, control);
987 out:
988         mutex_unlock(lock);
989 
990         return ret;
991 }
992 
993 static unsigned long ds3231_clk_sqw_recalc_rate(struct clk_hw *hw,
994                                                 unsigned long parent_rate)
995 {
996         struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
997         int control;
998         int rate_sel = 0;
999 
1000         control = i2c_smbus_read_byte_data(ds1307->client, DS1337_REG_CONTROL);
1001         if (control < 0)
1002                 return control;
1003         if (control & DS1337_BIT_RS1)
1004                 rate_sel += 1;
1005         if (control & DS1337_BIT_RS2)
1006                 rate_sel += 2;
1007 
1008         return ds3231_clk_sqw_rates[rate_sel];
1009 }
1010 
1011 static long ds3231_clk_sqw_round_rate(struct clk_hw *hw, unsigned long rate,
1012                                         unsigned long *prate)
1013 {
1014         int i;
1015 
1016         for (i = ARRAY_SIZE(ds3231_clk_sqw_rates) - 1; i >= 0; i--) {
1017                 if (ds3231_clk_sqw_rates[i] <= rate)
1018                         return ds3231_clk_sqw_rates[i];
1019         }
1020 
1021         return 0;
1022 }
1023 
1024 static int ds3231_clk_sqw_set_rate(struct clk_hw *hw, unsigned long rate,
1025                                         unsigned long parent_rate)
1026 {
1027         struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
1028         int control = 0;
1029         int rate_sel;
1030 
1031         for (rate_sel = 0; rate_sel < ARRAY_SIZE(ds3231_clk_sqw_rates);
1032                         rate_sel++) {
1033                 if (ds3231_clk_sqw_rates[rate_sel] == rate)
1034                         break;
1035         }
1036 
1037         if (rate_sel == ARRAY_SIZE(ds3231_clk_sqw_rates))
1038                 return -EINVAL;
1039 
1040         if (rate_sel & 1)
1041                 control |= DS1337_BIT_RS1;
1042         if (rate_sel & 2)
1043                 control |= DS1337_BIT_RS2;
1044 
1045         return ds1337_write_control(ds1307, DS1337_BIT_RS1 | DS1337_BIT_RS2,
1046                                 control);
1047 }
1048 
1049 static int ds3231_clk_sqw_prepare(struct clk_hw *hw)
1050 {
1051         struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
1052 
1053         return ds1337_write_control(ds1307, DS1337_BIT_INTCN, 0);
1054 }
1055 
1056 static void ds3231_clk_sqw_unprepare(struct clk_hw *hw)
1057 {
1058         struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
1059 
1060         ds1337_write_control(ds1307, DS1337_BIT_INTCN, DS1337_BIT_INTCN);
1061 }
1062 
1063 static int ds3231_clk_sqw_is_prepared(struct clk_hw *hw)
1064 {
1065         struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
1066         int control;
1067 
1068         control = i2c_smbus_read_byte_data(ds1307->client, DS1337_REG_CONTROL);
1069         if (control < 0)
1070                 return control;
1071 
1072         return !(control & DS1337_BIT_INTCN);
1073 }
1074 
1075 static const struct clk_ops ds3231_clk_sqw_ops = {
1076         .prepare = ds3231_clk_sqw_prepare,
1077         .unprepare = ds3231_clk_sqw_unprepare,
1078         .is_prepared = ds3231_clk_sqw_is_prepared,
1079         .recalc_rate = ds3231_clk_sqw_recalc_rate,
1080         .round_rate = ds3231_clk_sqw_round_rate,
1081         .set_rate = ds3231_clk_sqw_set_rate,
1082 };
1083 
1084 static unsigned long ds3231_clk_32khz_recalc_rate(struct clk_hw *hw,
1085                                                 unsigned long parent_rate)
1086 {
1087         return 32768;
1088 }
1089 
1090 static int ds3231_clk_32khz_control(struct ds1307 *ds1307, bool enable)
1091 {
1092         struct i2c_client *client = ds1307->client;
1093         struct mutex *lock = &ds1307->rtc->ops_lock;
1094         int status;
1095         int ret;
1096 
1097         mutex_lock(lock);
1098 
1099         status = i2c_smbus_read_byte_data(client, DS1337_REG_STATUS);
1100         if (status < 0) {
1101                 ret = status;
1102                 goto out;
1103         }
1104 
1105         if (enable)
1106                 status |= DS3231_BIT_EN32KHZ;
1107         else
1108                 status &= ~DS3231_BIT_EN32KHZ;
1109 
1110         ret = i2c_smbus_write_byte_data(client, DS1337_REG_STATUS, status);
1111 out:
1112         mutex_unlock(lock);
1113 
1114         return ret;
1115 }
1116 
1117 static int ds3231_clk_32khz_prepare(struct clk_hw *hw)
1118 {
1119         struct ds1307 *ds1307 = clk_32khz_to_ds1307(hw);
1120 
1121         return ds3231_clk_32khz_control(ds1307, true);
1122 }
1123 
1124 static void ds3231_clk_32khz_unprepare(struct clk_hw *hw)
1125 {
1126         struct ds1307 *ds1307 = clk_32khz_to_ds1307(hw);
1127 
1128         ds3231_clk_32khz_control(ds1307, false);
1129 }
1130 
1131 static int ds3231_clk_32khz_is_prepared(struct clk_hw *hw)
1132 {
1133         struct ds1307 *ds1307 = clk_32khz_to_ds1307(hw);
1134         int status;
1135 
1136         status = i2c_smbus_read_byte_data(ds1307->client, DS1337_REG_STATUS);
1137         if (status < 0)
1138                 return status;
1139 
1140         return !!(status & DS3231_BIT_EN32KHZ);
1141 }
1142 
1143 static const struct clk_ops ds3231_clk_32khz_ops = {
1144         .prepare = ds3231_clk_32khz_prepare,
1145         .unprepare = ds3231_clk_32khz_unprepare,
1146         .is_prepared = ds3231_clk_32khz_is_prepared,
1147         .recalc_rate = ds3231_clk_32khz_recalc_rate,
1148 };
1149 
1150 static struct clk_init_data ds3231_clks_init[] = {
1151         [DS3231_CLK_SQW] = {
1152                 .name = "ds3231_clk_sqw",
1153                 .ops = &ds3231_clk_sqw_ops,
1154         },
1155         [DS3231_CLK_32KHZ] = {
1156                 .name = "ds3231_clk_32khz",
1157                 .ops = &ds3231_clk_32khz_ops,
1158         },
1159 };
1160 
1161 static int ds3231_clks_register(struct ds1307 *ds1307)
1162 {
1163         struct i2c_client *client = ds1307->client;
1164         struct device_node *node = client->dev.of_node;
1165         struct clk_onecell_data *onecell;
1166         int i;
1167 
1168         onecell = devm_kzalloc(&client->dev, sizeof(*onecell), GFP_KERNEL);
1169         if (!onecell)
1170                 return -ENOMEM;
1171 
1172         onecell->clk_num = ARRAY_SIZE(ds3231_clks_init);
1173         onecell->clks = devm_kcalloc(&client->dev, onecell->clk_num,
1174                                         sizeof(onecell->clks[0]), GFP_KERNEL);
1175         if (!onecell->clks)
1176                 return -ENOMEM;
1177 
1178         for (i = 0; i < ARRAY_SIZE(ds3231_clks_init); i++) {
1179                 struct clk_init_data init = ds3231_clks_init[i];
1180 
1181                 /*
1182                  * Interrupt signal due to alarm conditions and square-wave
1183                  * output share same pin, so don't initialize both.
1184                  */
1185                 if (i == DS3231_CLK_SQW && test_bit(HAS_ALARM, &ds1307->flags))
1186                         continue;
1187 
1188                 /* optional override of the clockname */
1189                 of_property_read_string_index(node, "clock-output-names", i,
1190                                                 &init.name);
1191                 ds1307->clks[i].init = &init;
1192 
1193                 onecell->clks[i] = devm_clk_register(&client->dev,
1194                                                         &ds1307->clks[i]);
1195                 if (IS_ERR(onecell->clks[i]))
1196                         return PTR_ERR(onecell->clks[i]);
1197         }
1198 
1199         if (!node)
1200                 return 0;
1201 
1202         of_clk_add_provider(node, of_clk_src_onecell_get, onecell);
1203 
1204         return 0;
1205 }
1206 
1207 static void ds1307_clks_register(struct ds1307 *ds1307)
1208 {
1209         int ret;
1210 
1211         if (ds1307->type != ds_3231)
1212                 return;
1213 
1214         ret = ds3231_clks_register(ds1307);
1215         if (ret) {
1216                 dev_warn(&ds1307->client->dev,
1217                         "unable to register clock device %d\n", ret);
1218         }
1219 }
1220 
1221 #else
1222 
1223 static void ds1307_clks_register(struct ds1307 *ds1307)
1224 {
1225 }
1226 
1227 #endif /* CONFIG_COMMON_CLK */
1228 
1229 static int ds1307_probe(struct i2c_client *client,
1230                         const struct i2c_device_id *id)
1231 {
1232         struct ds1307           *ds1307;
1233         int                     err = -ENODEV;
1234         int                     tmp;
1235         struct chip_desc        *chip = &chips[id->driver_data];
1236         struct i2c_adapter      *adapter = to_i2c_adapter(client->dev.parent);
1237         bool                    want_irq = false;
1238         bool                    ds1307_can_wakeup_device = false;
1239         unsigned char           *buf;
1240         struct ds1307_platform_data *pdata = dev_get_platdata(&client->dev);
1241         irq_handler_t   irq_handler = ds1307_irq;
1242 
1243         static const int        bbsqi_bitpos[] = {
1244                 [ds_1337] = 0,
1245                 [ds_1339] = DS1339_BIT_BBSQI,
1246                 [ds_3231] = DS3231_BIT_BBSQW,
1247         };
1248         const struct rtc_class_ops *rtc_ops = &ds13xx_rtc_ops;
1249 
1250         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)
1251             && !i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
1252                 return -EIO;
1253 
1254         ds1307 = devm_kzalloc(&client->dev, sizeof(struct ds1307), GFP_KERNEL);
1255         if (!ds1307)
1256                 return -ENOMEM;
1257 
1258         i2c_set_clientdata(client, ds1307);
1259 
1260         ds1307->client  = client;
1261         ds1307->type    = id->driver_data;
1262 
1263         if (!pdata && client->dev.of_node)
1264                 ds1307_trickle_of_init(client, chip);
1265         else if (pdata && pdata->trickle_charger_setup)
1266                 chip->trickle_charger_setup = pdata->trickle_charger_setup;
1267 
1268         if (chip->trickle_charger_setup && chip->trickle_charger_reg) {
1269                 dev_dbg(&client->dev, "writing trickle charger info 0x%x to 0x%x\n",
1270                     DS13XX_TRICKLE_CHARGER_MAGIC | chip->trickle_charger_setup,
1271                     chip->trickle_charger_reg);
1272                 i2c_smbus_write_byte_data(client, chip->trickle_charger_reg,
1273                     DS13XX_TRICKLE_CHARGER_MAGIC |
1274                     chip->trickle_charger_setup);
1275         }
1276 
1277         buf = ds1307->regs;
1278         if (i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) {
1279                 ds1307->read_block_data = ds1307_native_smbus_read_block_data;
1280                 ds1307->write_block_data = ds1307_native_smbus_write_block_data;
1281         } else {
1282                 ds1307->read_block_data = ds1307_read_block_data;
1283                 ds1307->write_block_data = ds1307_write_block_data;
1284         }
1285 
1286 #ifdef CONFIG_OF
1287 /*
1288  * For devices with no IRQ directly connected to the SoC, the RTC chip
1289  * can be forced as a wakeup source by stating that explicitly in
1290  * the device's .dts file using the "wakeup-source" boolean property.
1291  * If the "wakeup-source" property is set, don't request an IRQ.
1292  * This will guarantee the 'wakealarm' sysfs entry is available on the device,
1293  * if supported by the RTC.
1294  */
1295         if (of_property_read_bool(client->dev.of_node, "wakeup-source")) {
1296                 ds1307_can_wakeup_device = true;
1297         }
1298 #endif
1299 
1300         switch (ds1307->type) {
1301         case ds_1337:
1302         case ds_1339:
1303         case ds_3231:
1304                 /* get registers that the "rtc" read below won't read... */
1305                 tmp = ds1307->read_block_data(ds1307->client,
1306                                 DS1337_REG_CONTROL, 2, buf);
1307                 if (tmp != 2) {
1308                         dev_dbg(&client->dev, "read error %d\n", tmp);
1309                         err = -EIO;
1310                         goto exit;
1311                 }
1312 
1313                 /* oscillator off?  turn it on, so clock can tick. */
1314                 if (ds1307->regs[0] & DS1337_BIT_nEOSC)
1315                         ds1307->regs[0] &= ~DS1337_BIT_nEOSC;
1316 
1317                 /*
1318                  * Using IRQ or defined as wakeup-source?
1319                  * Disable the square wave and both alarms.
1320                  * For some variants, be sure alarms can trigger when we're
1321                  * running on Vbackup (BBSQI/BBSQW)
1322                  */
1323                 if (chip->alarm && (ds1307->client->irq > 0 ||
1324                                                 ds1307_can_wakeup_device)) {
1325                         ds1307->regs[0] |= DS1337_BIT_INTCN
1326                                         | bbsqi_bitpos[ds1307->type];
1327                         ds1307->regs[0] &= ~(DS1337_BIT_A2IE | DS1337_BIT_A1IE);
1328 
1329                         want_irq = true;
1330                 }
1331 
1332                 i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL,
1333                                                         ds1307->regs[0]);
1334 
1335                 /* oscillator fault?  clear flag, and warn */
1336                 if (ds1307->regs[1] & DS1337_BIT_OSF) {
1337                         i2c_smbus_write_byte_data(client, DS1337_REG_STATUS,
1338                                 ds1307->regs[1] & ~DS1337_BIT_OSF);
1339                         dev_warn(&client->dev, "SET TIME!\n");
1340                 }
1341                 break;
1342 
1343         case rx_8025:
1344                 tmp = i2c_smbus_read_i2c_block_data(ds1307->client,
1345                                 RX8025_REG_CTRL1 << 4 | 0x08, 2, buf);
1346                 if (tmp != 2) {
1347                         dev_dbg(&client->dev, "read error %d\n", tmp);
1348                         err = -EIO;
1349                         goto exit;
1350                 }
1351 
1352                 /* oscillator off?  turn it on, so clock can tick. */
1353                 if (!(ds1307->regs[1] & RX8025_BIT_XST)) {
1354                         ds1307->regs[1] |= RX8025_BIT_XST;
1355                         i2c_smbus_write_byte_data(client,
1356                                                   RX8025_REG_CTRL2 << 4 | 0x08,
1357                                                   ds1307->regs[1]);
1358                         dev_warn(&client->dev,
1359                                  "oscillator stop detected - SET TIME!\n");
1360                 }
1361 
1362                 if (ds1307->regs[1] & RX8025_BIT_PON) {
1363                         ds1307->regs[1] &= ~RX8025_BIT_PON;
1364                         i2c_smbus_write_byte_data(client,
1365                                                   RX8025_REG_CTRL2 << 4 | 0x08,
1366                                                   ds1307->regs[1]);
1367                         dev_warn(&client->dev, "power-on detected\n");
1368                 }
1369 
1370                 if (ds1307->regs[1] & RX8025_BIT_VDET) {
1371                         ds1307->regs[1] &= ~RX8025_BIT_VDET;
1372                         i2c_smbus_write_byte_data(client,
1373                                                   RX8025_REG_CTRL2 << 4 | 0x08,
1374                                                   ds1307->regs[1]);
1375                         dev_warn(&client->dev, "voltage drop detected\n");
1376                 }
1377 
1378                 /* make sure we are running in 24hour mode */
1379                 if (!(ds1307->regs[0] & RX8025_BIT_2412)) {
1380                         u8 hour;
1381 
1382                         /* switch to 24 hour mode */
1383                         i2c_smbus_write_byte_data(client,
1384                                                   RX8025_REG_CTRL1 << 4 | 0x08,
1385                                                   ds1307->regs[0] |
1386                                                   RX8025_BIT_2412);
1387 
1388                         tmp = i2c_smbus_read_i2c_block_data(ds1307->client,
1389                                         RX8025_REG_CTRL1 << 4 | 0x08, 2, buf);
1390                         if (tmp != 2) {
1391                                 dev_dbg(&client->dev, "read error %d\n", tmp);
1392                                 err = -EIO;
1393                                 goto exit;
1394                         }
1395 
1396                         /* correct hour */
1397                         hour = bcd2bin(ds1307->regs[DS1307_REG_HOUR]);
1398                         if (hour == 12)
1399                                 hour = 0;
1400                         if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
1401                                 hour += 12;
1402 
1403                         i2c_smbus_write_byte_data(client,
1404                                                   DS1307_REG_HOUR << 4 | 0x08,
1405                                                   hour);
1406                 }
1407                 break;
1408         case ds_1388:
1409                 ds1307->offset = 1; /* Seconds starts at 1 */
1410                 break;
1411         case mcp794xx:
1412                 rtc_ops = &mcp794xx_rtc_ops;
1413                 if (ds1307->client->irq > 0 && chip->alarm) {
1414                         irq_handler = mcp794xx_irq;
1415                         want_irq = true;
1416                 }
1417                 break;
1418         default:
1419                 break;
1420         }
1421 
1422 read_rtc:
1423         /* read RTC registers */
1424         tmp = ds1307->read_block_data(ds1307->client, ds1307->offset, 8, buf);
1425         if (tmp != 8) {
1426                 dev_dbg(&client->dev, "read error %d\n", tmp);
1427                 err = -EIO;
1428                 goto exit;
1429         }
1430 
1431         /*
1432          * minimal sanity checking; some chips (like DS1340) don't
1433          * specify the extra bits as must-be-zero, but there are
1434          * still a few values that are clearly out-of-range.
1435          */
1436         tmp = ds1307->regs[DS1307_REG_SECS];
1437         switch (ds1307->type) {
1438         case ds_1307:
1439         case m41t00:
1440                 /* clock halted?  turn it on, so clock can tick. */
1441                 if (tmp & DS1307_BIT_CH) {
1442                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
1443                         dev_warn(&client->dev, "SET TIME!\n");
1444                         goto read_rtc;
1445                 }
1446                 break;
1447         case ds_1338:
1448                 /* clock halted?  turn it on, so clock can tick. */
1449                 if (tmp & DS1307_BIT_CH)
1450                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
1451 
1452                 /* oscillator fault?  clear flag, and warn */
1453                 if (ds1307->regs[DS1307_REG_CONTROL] & DS1338_BIT_OSF) {
1454                         i2c_smbus_write_byte_data(client, DS1307_REG_CONTROL,
1455                                         ds1307->regs[DS1307_REG_CONTROL]
1456                                         & ~DS1338_BIT_OSF);
1457                         dev_warn(&client->dev, "SET TIME!\n");
1458                         goto read_rtc;
1459                 }
1460                 break;
1461         case ds_1340:
1462                 /* clock halted?  turn it on, so clock can tick. */
1463                 if (tmp & DS1340_BIT_nEOSC)
1464                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
1465 
1466                 tmp = i2c_smbus_read_byte_data(client, DS1340_REG_FLAG);
1467                 if (tmp < 0) {
1468                         dev_dbg(&client->dev, "read error %d\n", tmp);
1469                         err = -EIO;
1470                         goto exit;
1471                 }
1472 
1473                 /* oscillator fault?  clear flag, and warn */
1474                 if (tmp & DS1340_BIT_OSF) {
1475                         i2c_smbus_write_byte_data(client, DS1340_REG_FLAG, 0);
1476                         dev_warn(&client->dev, "SET TIME!\n");
1477                 }
1478                 break;
1479         case mcp794xx:
1480                 /* make sure that the backup battery is enabled */
1481                 if (!(ds1307->regs[DS1307_REG_WDAY] & MCP794XX_BIT_VBATEN)) {
1482                         i2c_smbus_write_byte_data(client, DS1307_REG_WDAY,
1483                                         ds1307->regs[DS1307_REG_WDAY]
1484                                         | MCP794XX_BIT_VBATEN);
1485                 }
1486 
1487                 /* clock halted?  turn it on, so clock can tick. */
1488                 if (!(tmp & MCP794XX_BIT_ST)) {
1489                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS,
1490                                         MCP794XX_BIT_ST);
1491                         dev_warn(&client->dev, "SET TIME!\n");
1492                         goto read_rtc;
1493                 }
1494 
1495                 break;
1496         default:
1497                 break;
1498         }
1499 
1500         tmp = ds1307->regs[DS1307_REG_HOUR];
1501         switch (ds1307->type) {
1502         case ds_1340:
1503         case m41t00:
1504                 /*
1505                  * NOTE: ignores century bits; fix before deploying
1506                  * systems that will run through year 2100.
1507                  */
1508                 break;
1509         case rx_8025:
1510                 break;
1511         default:
1512                 if (!(tmp & DS1307_BIT_12HR))
1513                         break;
1514 
1515                 /*
1516                  * Be sure we're in 24 hour mode.  Multi-master systems
1517                  * take note...
1518                  */
1519                 tmp = bcd2bin(tmp & 0x1f);
1520                 if (tmp == 12)
1521                         tmp = 0;
1522                 if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
1523                         tmp += 12;
1524                 i2c_smbus_write_byte_data(client,
1525                                 ds1307->offset + DS1307_REG_HOUR,
1526                                 bin2bcd(tmp));
1527         }
1528 
1529         if (want_irq) {
1530                 device_set_wakeup_capable(&client->dev, true);
1531                 set_bit(HAS_ALARM, &ds1307->flags);
1532         }
1533         ds1307->rtc = devm_rtc_device_register(&client->dev, client->name,
1534                                 rtc_ops, THIS_MODULE);
1535         if (IS_ERR(ds1307->rtc)) {
1536                 return PTR_ERR(ds1307->rtc);
1537         }
1538 
1539         if (ds1307_can_wakeup_device && ds1307->client->irq <= 0) {
1540                 /* Disable request for an IRQ */
1541                 want_irq = false;
1542                 dev_info(&client->dev, "'wakeup-source' is set, request for an IRQ is disabled!\n");
1543                 /* We cannot support UIE mode if we do not have an IRQ line */
1544                 ds1307->rtc->uie_unsupported = 1;
1545         }
1546 
1547         if (want_irq) {
1548                 err = devm_request_threaded_irq(&client->dev,
1549                                                 client->irq, NULL, irq_handler,
1550                                                 IRQF_SHARED | IRQF_ONESHOT,
1551                                                 ds1307->rtc->name, client);
1552                 if (err) {
1553                         client->irq = 0;
1554                         device_set_wakeup_capable(&client->dev, false);
1555                         clear_bit(HAS_ALARM, &ds1307->flags);
1556                         dev_err(&client->dev, "unable to request IRQ!\n");
1557                 } else
1558                         dev_dbg(&client->dev, "got IRQ %d\n", client->irq);
1559         }
1560 
1561         if (chip->nvram_size) {
1562 
1563                 ds1307->nvram = devm_kzalloc(&client->dev,
1564                                         sizeof(struct bin_attribute),
1565                                         GFP_KERNEL);
1566                 if (!ds1307->nvram) {
1567                         dev_err(&client->dev, "cannot allocate memory for nvram sysfs\n");
1568                 } else {
1569 
1570                         ds1307->nvram->attr.name = "nvram";
1571                         ds1307->nvram->attr.mode = S_IRUGO | S_IWUSR;
1572 
1573                         sysfs_bin_attr_init(ds1307->nvram);
1574 
1575                         ds1307->nvram->read = ds1307_nvram_read;
1576                         ds1307->nvram->write = ds1307_nvram_write;
1577                         ds1307->nvram->size = chip->nvram_size;
1578                         ds1307->nvram_offset = chip->nvram_offset;
1579 
1580                         err = sysfs_create_bin_file(&client->dev.kobj,
1581                                                     ds1307->nvram);
1582                         if (err) {
1583                                 dev_err(&client->dev,
1584                                         "unable to create sysfs file: %s\n",
1585                                         ds1307->nvram->attr.name);
1586                         } else {
1587                                 set_bit(HAS_NVRAM, &ds1307->flags);
1588                                 dev_info(&client->dev, "%zu bytes nvram\n",
1589                                          ds1307->nvram->size);
1590                         }
1591                 }
1592         }
1593 
1594         ds1307_hwmon_register(ds1307);
1595         ds1307_clks_register(ds1307);
1596 
1597         return 0;
1598 
1599 exit:
1600         return err;
1601 }
1602 
1603 static int ds1307_remove(struct i2c_client *client)
1604 {
1605         struct ds1307 *ds1307 = i2c_get_clientdata(client);
1606 
1607         if (test_and_clear_bit(HAS_NVRAM, &ds1307->flags))
1608                 sysfs_remove_bin_file(&client->dev.kobj, ds1307->nvram);
1609 
1610         return 0;
1611 }
1612 
1613 static struct i2c_driver ds1307_driver = {
1614         .driver = {
1615                 .name   = "rtc-ds1307",
1616         },
1617         .probe          = ds1307_probe,
1618         .remove         = ds1307_remove,
1619         .id_table       = ds1307_id,
1620 };
1621 
1622 module_i2c_driver(ds1307_driver);
1623 
1624 MODULE_DESCRIPTION("RTC driver for DS1307 and similar chips");
1625 MODULE_LICENSE("GPL");
1626 

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