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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/acpi.h>
 15 #include <linux/bcd.h>
 16 #include <linux/i2c.h>
 17 #include <linux/init.h>
 18 #include <linux/module.h>
 19 #include <linux/rtc/ds1307.h>
 20 #include <linux/rtc.h>
 21 #include <linux/slab.h>
 22 #include <linux/string.h>
 23 #include <linux/hwmon.h>
 24 #include <linux/hwmon-sysfs.h>
 25 #include <linux/clk-provider.h>
 26 
 27 /*
 28  * We can't determine type by probing, but if we expect pre-Linux code
 29  * to have set the chip up as a clock (turning on the oscillator and
 30  * setting the date and time), Linux can ignore the non-clock features.
 31  * That's a natural job for a factory or repair bench.
 32  */
 33 enum ds_type {
 34         ds_1307,
 35         ds_1337,
 36         ds_1338,
 37         ds_1339,
 38         ds_1340,
 39         ds_1388,
 40         ds_3231,
 41         m41t00,
 42         mcp794xx,
 43         rx_8025,
 44         last_ds_type /* always last */
 45         /* rs5c372 too?  different address... */
 46 };
 47 
 48 
 49 /* RTC registers don't differ much, except for the century flag */
 50 #define DS1307_REG_SECS         0x00    /* 00-59 */
 51 #       define DS1307_BIT_CH            0x80
 52 #       define DS1340_BIT_nEOSC         0x80
 53 #       define MCP794XX_BIT_ST          0x80
 54 #define DS1307_REG_MIN          0x01    /* 00-59 */
 55 #define DS1307_REG_HOUR         0x02    /* 00-23, or 1-12{am,pm} */
 56 #       define DS1307_BIT_12HR          0x40    /* in REG_HOUR */
 57 #       define DS1307_BIT_PM            0x20    /* in REG_HOUR */
 58 #       define DS1340_BIT_CENTURY_EN    0x80    /* in REG_HOUR */
 59 #       define DS1340_BIT_CENTURY       0x40    /* in REG_HOUR */
 60 #define DS1307_REG_WDAY         0x03    /* 01-07 */
 61 #       define MCP794XX_BIT_VBATEN      0x08
 62 #define DS1307_REG_MDAY         0x04    /* 01-31 */
 63 #define DS1307_REG_MONTH        0x05    /* 01-12 */
 64 #       define DS1337_BIT_CENTURY       0x80    /* in REG_MONTH */
 65 #define DS1307_REG_YEAR         0x06    /* 00-99 */
 66 
 67 /*
 68  * Other registers (control, status, alarms, trickle charge, NVRAM, etc)
 69  * start at 7, and they differ a LOT. Only control and status matter for
 70  * basic RTC date and time functionality; be careful using them.
 71  */
 72 #define DS1307_REG_CONTROL      0x07            /* or ds1338 */
 73 #       define DS1307_BIT_OUT           0x80
 74 #       define DS1338_BIT_OSF           0x20
 75 #       define DS1307_BIT_SQWE          0x10
 76 #       define DS1307_BIT_RS1           0x02
 77 #       define DS1307_BIT_RS0           0x01
 78 #define DS1337_REG_CONTROL      0x0e
 79 #       define DS1337_BIT_nEOSC         0x80
 80 #       define DS1339_BIT_BBSQI         0x20
 81 #       define DS3231_BIT_BBSQW         0x40 /* same as BBSQI */
 82 #       define DS1337_BIT_RS2           0x10
 83 #       define DS1337_BIT_RS1           0x08
 84 #       define DS1337_BIT_INTCN         0x04
 85 #       define DS1337_BIT_A2IE          0x02
 86 #       define DS1337_BIT_A1IE          0x01
 87 #define DS1340_REG_CONTROL      0x07
 88 #       define DS1340_BIT_OUT           0x80
 89 #       define DS1340_BIT_FT            0x40
 90 #       define DS1340_BIT_CALIB_SIGN    0x20
 91 #       define DS1340_M_CALIBRATION     0x1f
 92 #define DS1340_REG_FLAG         0x09
 93 #       define DS1340_BIT_OSF           0x80
 94 #define DS1337_REG_STATUS       0x0f
 95 #       define DS1337_BIT_OSF           0x80
 96 #       define DS3231_BIT_EN32KHZ       0x08
 97 #       define DS1337_BIT_A2I           0x02
 98 #       define DS1337_BIT_A1I           0x01
 99 #define DS1339_REG_ALARM1_SECS  0x07
100 
101 #define DS13XX_TRICKLE_CHARGER_MAGIC    0xa0
102 
103 #define RX8025_REG_CTRL1        0x0e
104 #       define RX8025_BIT_2412          0x20
105 #define RX8025_REG_CTRL2        0x0f
106 #       define RX8025_BIT_PON           0x10
107 #       define RX8025_BIT_VDET          0x40
108 #       define RX8025_BIT_XST           0x20
109 
110 
111 struct ds1307 {
112         u8                      offset; /* register's offset */
113         u8                      regs[11];
114         u16                     nvram_offset;
115         struct bin_attribute    *nvram;
116         enum ds_type            type;
117         unsigned long           flags;
118 #define HAS_NVRAM       0               /* bit 0 == sysfs file active */
119 #define HAS_ALARM       1               /* bit 1 == irq claimed */
120         struct i2c_client       *client;
121         struct rtc_device       *rtc;
122         s32 (*read_block_data)(const struct i2c_client *client, u8 command,
123                                u8 length, u8 *values);
124         s32 (*write_block_data)(const struct i2c_client *client, u8 command,
125                                 u8 length, const u8 *values);
126 #ifdef CONFIG_COMMON_CLK
127         struct clk_hw           clks[2];
128 #endif
129 };
130 
131 struct chip_desc {
132         unsigned                alarm:1;
133         u16                     nvram_offset;
134         u16                     nvram_size;
135         u16                     trickle_charger_reg;
136         u8                      trickle_charger_setup;
137         u8                      (*do_trickle_setup)(struct i2c_client *, uint32_t, bool);
138 };
139 
140 static u8 do_trickle_setup_ds1339(struct i2c_client *,
141                                   uint32_t ohms, bool diode);
142 
143 static struct chip_desc chips[last_ds_type] = {
144         [ds_1307] = {
145                 .nvram_offset   = 8,
146                 .nvram_size     = 56,
147         },
148         [ds_1337] = {
149                 .alarm          = 1,
150         },
151         [ds_1338] = {
152                 .nvram_offset   = 8,
153                 .nvram_size     = 56,
154         },
155         [ds_1339] = {
156                 .alarm          = 1,
157                 .trickle_charger_reg = 0x10,
158                 .do_trickle_setup = &do_trickle_setup_ds1339,
159         },
160         [ds_1340] = {
161                 .trickle_charger_reg = 0x08,
162         },
163         [ds_1388] = {
164                 .trickle_charger_reg = 0x0a,
165         },
166         [ds_3231] = {
167                 .alarm          = 1,
168         },
169         [mcp794xx] = {
170                 .alarm          = 1,
171                 /* this is battery backed SRAM */
172                 .nvram_offset   = 0x20,
173                 .nvram_size     = 0x40,
174         },
175 };
176 
177 static const struct i2c_device_id ds1307_id[] = {
178         { "ds1307", ds_1307 },
179         { "ds1337", ds_1337 },
180         { "ds1338", ds_1338 },
181         { "ds1339", ds_1339 },
182         { "ds1388", ds_1388 },
183         { "ds1340", ds_1340 },
184         { "ds3231", ds_3231 },
185         { "m41t00", m41t00 },
186         { "mcp7940x", mcp794xx },
187         { "mcp7941x", mcp794xx },
188         { "pt7c4338", ds_1307 },
189         { "rx8025", rx_8025 },
190         { "isl12057", ds_1337 },
191         { }
192 };
193 MODULE_DEVICE_TABLE(i2c, ds1307_id);
194 
195 #ifdef CONFIG_ACPI
196 static const struct acpi_device_id ds1307_acpi_ids[] = {
197         { .id = "DS1307", .driver_data = ds_1307 },
198         { .id = "DS1337", .driver_data = ds_1337 },
199         { .id = "DS1338", .driver_data = ds_1338 },
200         { .id = "DS1339", .driver_data = ds_1339 },
201         { .id = "DS1388", .driver_data = ds_1388 },
202         { .id = "DS1340", .driver_data = ds_1340 },
203         { .id = "DS3231", .driver_data = ds_3231 },
204         { .id = "M41T00", .driver_data = m41t00 },
205         { .id = "MCP7940X", .driver_data = mcp794xx },
206         { .id = "MCP7941X", .driver_data = mcp794xx },
207         { .id = "PT7C4338", .driver_data = ds_1307 },
208         { .id = "RX8025", .driver_data = rx_8025 },
209         { .id = "ISL12057", .driver_data = ds_1337 },
210         { }
211 };
212 MODULE_DEVICE_TABLE(acpi, ds1307_acpi_ids);
213 #endif
214 
215 /*----------------------------------------------------------------------*/
216 
217 #define BLOCK_DATA_MAX_TRIES 10
218 
219 static s32 ds1307_read_block_data_once(const struct i2c_client *client,
220                                        u8 command, u8 length, u8 *values)
221 {
222         s32 i, data;
223 
224         for (i = 0; i < length; i++) {
225                 data = i2c_smbus_read_byte_data(client, command + i);
226                 if (data < 0)
227                         return data;
228                 values[i] = data;
229         }
230         return i;
231 }
232 
233 static s32 ds1307_read_block_data(const struct i2c_client *client, u8 command,
234                                   u8 length, u8 *values)
235 {
236         u8 oldvalues[255];
237         s32 ret;
238         int tries = 0;
239 
240         dev_dbg(&client->dev, "ds1307_read_block_data (length=%d)\n", length);
241         ret = ds1307_read_block_data_once(client, command, length, values);
242         if (ret < 0)
243                 return ret;
244         do {
245                 if (++tries > BLOCK_DATA_MAX_TRIES) {
246                         dev_err(&client->dev,
247                                 "ds1307_read_block_data failed\n");
248                         return -EIO;
249                 }
250                 memcpy(oldvalues, values, length);
251                 ret = ds1307_read_block_data_once(client, command, length,
252                                                   values);
253                 if (ret < 0)
254                         return ret;
255         } while (memcmp(oldvalues, values, length));
256         return length;
257 }
258 
259 static s32 ds1307_write_block_data(const struct i2c_client *client, u8 command,
260                                    u8 length, const u8 *values)
261 {
262         u8 currvalues[255];
263         int tries = 0;
264 
265         dev_dbg(&client->dev, "ds1307_write_block_data (length=%d)\n", length);
266         do {
267                 s32 i, ret;
268 
269                 if (++tries > BLOCK_DATA_MAX_TRIES) {
270                         dev_err(&client->dev,
271                                 "ds1307_write_block_data failed\n");
272                         return -EIO;
273                 }
274                 for (i = 0; i < length; i++) {
275                         ret = i2c_smbus_write_byte_data(client, command + i,
276                                                         values[i]);
277                         if (ret < 0)
278                                 return ret;
279                 }
280                 ret = ds1307_read_block_data_once(client, command, length,
281                                                   currvalues);
282                 if (ret < 0)
283                         return ret;
284         } while (memcmp(currvalues, values, length));
285         return length;
286 }
287 
288 /*----------------------------------------------------------------------*/
289 
290 /* These RTC devices are not designed to be connected to a SMbus adapter.
291    SMbus limits block operations length to 32 bytes, whereas it's not
292    limited on I2C buses. As a result, accesses may exceed 32 bytes;
293    in that case, split them into smaller blocks */
294 
295 static s32 ds1307_native_smbus_write_block_data(const struct i2c_client *client,
296                                 u8 command, u8 length, const u8 *values)
297 {
298         u8 suboffset = 0;
299 
300         if (length <= I2C_SMBUS_BLOCK_MAX) {
301                 s32 retval = i2c_smbus_write_i2c_block_data(client,
302                                         command, length, values);
303                 if (retval < 0)
304                         return retval;
305                 return length;
306         }
307 
308         while (suboffset < length) {
309                 s32 retval = i2c_smbus_write_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 static s32 ds1307_native_smbus_read_block_data(const struct i2c_client *client,
322                                 u8 command, u8 length, u8 *values)
323 {
324         u8 suboffset = 0;
325 
326         if (length <= I2C_SMBUS_BLOCK_MAX)
327                 return i2c_smbus_read_i2c_block_data(client,
328                                         command, length, values);
329 
330         while (suboffset < length) {
331                 s32 retval = i2c_smbus_read_i2c_block_data(client,
332                                 command + suboffset,
333                                 min(I2C_SMBUS_BLOCK_MAX, length - suboffset),
334                                 values + suboffset);
335                 if (retval < 0)
336                         return retval;
337 
338                 suboffset += I2C_SMBUS_BLOCK_MAX;
339         }
340         return length;
341 }
342 
343 /*----------------------------------------------------------------------*/
344 
345 /*
346  * The ds1337 and ds1339 both have two alarms, but we only use the first
347  * one (with a "seconds" field).  For ds1337 we expect nINTA is our alarm
348  * signal; ds1339 chips have only one alarm signal.
349  */
350 static irqreturn_t ds1307_irq(int irq, void *dev_id)
351 {
352         struct i2c_client       *client = dev_id;
353         struct ds1307           *ds1307 = i2c_get_clientdata(client);
354         struct mutex            *lock = &ds1307->rtc->ops_lock;
355         int                     stat, control;
356 
357         mutex_lock(lock);
358         stat = i2c_smbus_read_byte_data(client, DS1337_REG_STATUS);
359         if (stat < 0)
360                 goto out;
361 
362         if (stat & DS1337_BIT_A1I) {
363                 stat &= ~DS1337_BIT_A1I;
364                 i2c_smbus_write_byte_data(client, DS1337_REG_STATUS, stat);
365 
366                 control = i2c_smbus_read_byte_data(client, DS1337_REG_CONTROL);
367                 if (control < 0)
368                         goto out;
369 
370                 control &= ~DS1337_BIT_A1IE;
371                 i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL, control);
372 
373                 rtc_update_irq(ds1307->rtc, 1, RTC_AF | RTC_IRQF);
374         }
375 
376 out:
377         mutex_unlock(lock);
378 
379         return IRQ_HANDLED;
380 }
381 
382 /*----------------------------------------------------------------------*/
383 
384 static int ds1307_get_time(struct device *dev, struct rtc_time *t)
385 {
386         struct ds1307   *ds1307 = dev_get_drvdata(dev);
387         int             tmp;
388 
389         /* read the RTC date and time registers all at once */
390         tmp = ds1307->read_block_data(ds1307->client,
391                 ds1307->offset, 7, ds1307->regs);
392         if (tmp != 7) {
393                 dev_err(dev, "%s error %d\n", "read", tmp);
394                 return -EIO;
395         }
396 
397         dev_dbg(dev, "%s: %7ph\n", "read", ds1307->regs);
398 
399         t->tm_sec = bcd2bin(ds1307->regs[DS1307_REG_SECS] & 0x7f);
400         t->tm_min = bcd2bin(ds1307->regs[DS1307_REG_MIN] & 0x7f);
401         tmp = ds1307->regs[DS1307_REG_HOUR] & 0x3f;
402         t->tm_hour = bcd2bin(tmp);
403         t->tm_wday = bcd2bin(ds1307->regs[DS1307_REG_WDAY] & 0x07) - 1;
404         t->tm_mday = bcd2bin(ds1307->regs[DS1307_REG_MDAY] & 0x3f);
405         tmp = ds1307->regs[DS1307_REG_MONTH] & 0x1f;
406         t->tm_mon = bcd2bin(tmp) - 1;
407         t->tm_year = bcd2bin(ds1307->regs[DS1307_REG_YEAR]) + 100;
408 
409 #ifdef CONFIG_RTC_DRV_DS1307_CENTURY
410         switch (ds1307->type) {
411         case ds_1337:
412         case ds_1339:
413         case ds_3231:
414                 if (ds1307->regs[DS1307_REG_MONTH] & DS1337_BIT_CENTURY)
415                         t->tm_year += 100;
416                 break;
417         case ds_1340:
418                 if (ds1307->regs[DS1307_REG_HOUR] & DS1340_BIT_CENTURY)
419                         t->tm_year += 100;
420                 break;
421         default:
422                 break;
423         }
424 #endif
425 
426         dev_dbg(dev, "%s secs=%d, mins=%d, "
427                 "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
428                 "read", t->tm_sec, t->tm_min,
429                 t->tm_hour, t->tm_mday,
430                 t->tm_mon, t->tm_year, t->tm_wday);
431 
432         /* initial clock setting can be undefined */
433         return rtc_valid_tm(t);
434 }
435 
436 static int ds1307_set_time(struct device *dev, struct rtc_time *t)
437 {
438         struct ds1307   *ds1307 = dev_get_drvdata(dev);
439         int             result;
440         int             tmp;
441         u8              *buf = ds1307->regs;
442 
443         dev_dbg(dev, "%s secs=%d, mins=%d, "
444                 "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
445                 "write", t->tm_sec, t->tm_min,
446                 t->tm_hour, t->tm_mday,
447                 t->tm_mon, t->tm_year, t->tm_wday);
448 
449 #ifdef CONFIG_RTC_DRV_DS1307_CENTURY
450         if (t->tm_year < 100)
451                 return -EINVAL;
452 
453         switch (ds1307->type) {
454         case ds_1337:
455         case ds_1339:
456         case ds_3231:
457         case ds_1340:
458                 if (t->tm_year > 299)
459                         return -EINVAL;
460         default:
461                 if (t->tm_year > 199)
462                         return -EINVAL;
463                 break;
464         }
465 #else
466         if (t->tm_year < 100 || t->tm_year > 199)
467                 return -EINVAL;
468 #endif
469 
470         buf[DS1307_REG_SECS] = bin2bcd(t->tm_sec);
471         buf[DS1307_REG_MIN] = bin2bcd(t->tm_min);
472         buf[DS1307_REG_HOUR] = bin2bcd(t->tm_hour);
473         buf[DS1307_REG_WDAY] = bin2bcd(t->tm_wday + 1);
474         buf[DS1307_REG_MDAY] = bin2bcd(t->tm_mday);
475         buf[DS1307_REG_MONTH] = bin2bcd(t->tm_mon + 1);
476 
477         /* assume 20YY not 19YY */
478         tmp = t->tm_year - 100;
479         buf[DS1307_REG_YEAR] = bin2bcd(tmp);
480 
481         switch (ds1307->type) {
482         case ds_1337:
483         case ds_1339:
484         case ds_3231:
485                 if (t->tm_year > 199)
486                         buf[DS1307_REG_MONTH] |= DS1337_BIT_CENTURY;
487                 break;
488         case ds_1340:
489                 buf[DS1307_REG_HOUR] |= DS1340_BIT_CENTURY_EN;
490                 if (t->tm_year > 199)
491                         buf[DS1307_REG_HOUR] |= DS1340_BIT_CENTURY;
492                 break;
493         case mcp794xx:
494                 /*
495                  * these bits were cleared when preparing the date/time
496                  * values and need to be set again before writing the
497                  * buffer out to the device.
498                  */
499                 buf[DS1307_REG_SECS] |= MCP794XX_BIT_ST;
500                 buf[DS1307_REG_WDAY] |= MCP794XX_BIT_VBATEN;
501                 break;
502         default:
503                 break;
504         }
505 
506         dev_dbg(dev, "%s: %7ph\n", "write", buf);
507 
508         result = ds1307->write_block_data(ds1307->client,
509                 ds1307->offset, 7, buf);
510         if (result < 0) {
511                 dev_err(dev, "%s error %d\n", "write", result);
512                 return result;
513         }
514         return 0;
515 }
516 
517 static int ds1337_read_alarm(struct device *dev, struct rtc_wkalrm *t)
518 {
519         struct i2c_client       *client = to_i2c_client(dev);
520         struct ds1307           *ds1307 = i2c_get_clientdata(client);
521         int                     ret;
522 
523         if (!test_bit(HAS_ALARM, &ds1307->flags))
524                 return -EINVAL;
525 
526         /* read all ALARM1, ALARM2, and status registers at once */
527         ret = ds1307->read_block_data(client,
528                         DS1339_REG_ALARM1_SECS, 9, ds1307->regs);
529         if (ret != 9) {
530                 dev_err(dev, "%s error %d\n", "alarm read", ret);
531                 return -EIO;
532         }
533 
534         dev_dbg(dev, "%s: %4ph, %3ph, %2ph\n", "alarm read",
535                 &ds1307->regs[0], &ds1307->regs[4], &ds1307->regs[7]);
536 
537         /*
538          * report alarm time (ALARM1); assume 24 hour and day-of-month modes,
539          * and that all four fields are checked matches
540          */
541         t->time.tm_sec = bcd2bin(ds1307->regs[0] & 0x7f);
542         t->time.tm_min = bcd2bin(ds1307->regs[1] & 0x7f);
543         t->time.tm_hour = bcd2bin(ds1307->regs[2] & 0x3f);
544         t->time.tm_mday = bcd2bin(ds1307->regs[3] & 0x3f);
545 
546         /* ... and status */
547         t->enabled = !!(ds1307->regs[7] & DS1337_BIT_A1IE);
548         t->pending = !!(ds1307->regs[8] & DS1337_BIT_A1I);
549 
550         dev_dbg(dev, "%s secs=%d, mins=%d, "
551                 "hours=%d, mday=%d, enabled=%d, pending=%d\n",
552                 "alarm read", t->time.tm_sec, t->time.tm_min,
553                 t->time.tm_hour, t->time.tm_mday,
554                 t->enabled, t->pending);
555 
556         return 0;
557 }
558 
559 static int ds1337_set_alarm(struct device *dev, struct rtc_wkalrm *t)
560 {
561         struct i2c_client       *client = to_i2c_client(dev);
562         struct ds1307           *ds1307 = i2c_get_clientdata(client);
563         unsigned char           *buf = ds1307->regs;
564         u8                      control, status;
565         int                     ret;
566 
567         if (!test_bit(HAS_ALARM, &ds1307->flags))
568                 return -EINVAL;
569 
570         dev_dbg(dev, "%s secs=%d, mins=%d, "
571                 "hours=%d, mday=%d, enabled=%d, pending=%d\n",
572                 "alarm set", t->time.tm_sec, t->time.tm_min,
573                 t->time.tm_hour, t->time.tm_mday,
574                 t->enabled, t->pending);
575 
576         /* read current status of both alarms and the chip */
577         ret = ds1307->read_block_data(client,
578                         DS1339_REG_ALARM1_SECS, 9, buf);
579         if (ret != 9) {
580                 dev_err(dev, "%s error %d\n", "alarm write", ret);
581                 return -EIO;
582         }
583         control = ds1307->regs[7];
584         status = ds1307->regs[8];
585 
586         dev_dbg(dev, "%s: %4ph, %3ph, %02x %02x\n", "alarm set (old status)",
587                 &ds1307->regs[0], &ds1307->regs[4], control, status);
588 
589         /* set ALARM1, using 24 hour and day-of-month modes */
590         buf[0] = bin2bcd(t->time.tm_sec);
591         buf[1] = bin2bcd(t->time.tm_min);
592         buf[2] = bin2bcd(t->time.tm_hour);
593         buf[3] = bin2bcd(t->time.tm_mday);
594 
595         /* set ALARM2 to non-garbage */
596         buf[4] = 0;
597         buf[5] = 0;
598         buf[6] = 0;
599 
600         /* disable alarms */
601         buf[7] = control & ~(DS1337_BIT_A1IE | DS1337_BIT_A2IE);
602         buf[8] = status & ~(DS1337_BIT_A1I | DS1337_BIT_A2I);
603 
604         ret = ds1307->write_block_data(client,
605                         DS1339_REG_ALARM1_SECS, 9, buf);
606         if (ret < 0) {
607                 dev_err(dev, "can't set alarm time\n");
608                 return ret;
609         }
610 
611         /* optionally enable ALARM1 */
612         if (t->enabled) {
613                 dev_dbg(dev, "alarm IRQ armed\n");
614                 buf[7] |= DS1337_BIT_A1IE;      /* only ALARM1 is used */
615                 i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL, buf[7]);
616         }
617 
618         return 0;
619 }
620 
621 static int ds1307_alarm_irq_enable(struct device *dev, unsigned int enabled)
622 {
623         struct i2c_client       *client = to_i2c_client(dev);
624         struct ds1307           *ds1307 = i2c_get_clientdata(client);
625         int                     ret;
626 
627         if (!test_bit(HAS_ALARM, &ds1307->flags))
628                 return -ENOTTY;
629 
630         ret = i2c_smbus_read_byte_data(client, DS1337_REG_CONTROL);
631         if (ret < 0)
632                 return ret;
633 
634         if (enabled)
635                 ret |= DS1337_BIT_A1IE;
636         else
637                 ret &= ~DS1337_BIT_A1IE;
638 
639         ret = i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL, ret);
640         if (ret < 0)
641                 return ret;
642 
643         return 0;
644 }
645 
646 static const struct rtc_class_ops ds13xx_rtc_ops = {
647         .read_time      = ds1307_get_time,
648         .set_time       = ds1307_set_time,
649         .read_alarm     = ds1337_read_alarm,
650         .set_alarm      = ds1337_set_alarm,
651         .alarm_irq_enable = ds1307_alarm_irq_enable,
652 };
653 
654 /*----------------------------------------------------------------------*/
655 
656 /*
657  * Alarm support for mcp794xx devices.
658  */
659 
660 #define MCP794XX_REG_WEEKDAY            0x3
661 #define MCP794XX_REG_WEEKDAY_WDAY_MASK  0x7
662 #define MCP794XX_REG_CONTROL            0x07
663 #       define MCP794XX_BIT_ALM0_EN     0x10
664 #       define MCP794XX_BIT_ALM1_EN     0x20
665 #define MCP794XX_REG_ALARM0_BASE        0x0a
666 #define MCP794XX_REG_ALARM0_CTRL        0x0d
667 #define MCP794XX_REG_ALARM1_BASE        0x11
668 #define MCP794XX_REG_ALARM1_CTRL        0x14
669 #       define MCP794XX_BIT_ALMX_IF     (1 << 3)
670 #       define MCP794XX_BIT_ALMX_C0     (1 << 4)
671 #       define MCP794XX_BIT_ALMX_C1     (1 << 5)
672 #       define MCP794XX_BIT_ALMX_C2     (1 << 6)
673 #       define MCP794XX_BIT_ALMX_POL    (1 << 7)
674 #       define MCP794XX_MSK_ALMX_MATCH  (MCP794XX_BIT_ALMX_C0 | \
675                                          MCP794XX_BIT_ALMX_C1 | \
676                                          MCP794XX_BIT_ALMX_C2)
677 
678 static irqreturn_t mcp794xx_irq(int irq, void *dev_id)
679 {
680         struct i2c_client       *client = dev_id;
681         struct ds1307           *ds1307 = i2c_get_clientdata(client);
682         struct mutex            *lock = &ds1307->rtc->ops_lock;
683         int reg, ret;
684 
685         mutex_lock(lock);
686 
687         /* Check and clear alarm 0 interrupt flag. */
688         reg = i2c_smbus_read_byte_data(client, MCP794XX_REG_ALARM0_CTRL);
689         if (reg < 0)
690                 goto out;
691         if (!(reg & MCP794XX_BIT_ALMX_IF))
692                 goto out;
693         reg &= ~MCP794XX_BIT_ALMX_IF;
694         ret = i2c_smbus_write_byte_data(client, MCP794XX_REG_ALARM0_CTRL, reg);
695         if (ret < 0)
696                 goto out;
697 
698         /* Disable alarm 0. */
699         reg = i2c_smbus_read_byte_data(client, MCP794XX_REG_CONTROL);
700         if (reg < 0)
701                 goto out;
702         reg &= ~MCP794XX_BIT_ALM0_EN;
703         ret = i2c_smbus_write_byte_data(client, MCP794XX_REG_CONTROL, reg);
704         if (ret < 0)
705                 goto out;
706 
707         rtc_update_irq(ds1307->rtc, 1, RTC_AF | RTC_IRQF);
708 
709 out:
710         mutex_unlock(lock);
711 
712         return IRQ_HANDLED;
713 }
714 
715 static int mcp794xx_read_alarm(struct device *dev, struct rtc_wkalrm *t)
716 {
717         struct i2c_client *client = to_i2c_client(dev);
718         struct ds1307 *ds1307 = i2c_get_clientdata(client);
719         u8 *regs = ds1307->regs;
720         int ret;
721 
722         if (!test_bit(HAS_ALARM, &ds1307->flags))
723                 return -EINVAL;
724 
725         /* Read control and alarm 0 registers. */
726         ret = ds1307->read_block_data(client, MCP794XX_REG_CONTROL, 10, regs);
727         if (ret < 0)
728                 return ret;
729 
730         t->enabled = !!(regs[0] & MCP794XX_BIT_ALM0_EN);
731 
732         /* Report alarm 0 time assuming 24-hour and day-of-month modes. */
733         t->time.tm_sec = bcd2bin(ds1307->regs[3] & 0x7f);
734         t->time.tm_min = bcd2bin(ds1307->regs[4] & 0x7f);
735         t->time.tm_hour = bcd2bin(ds1307->regs[5] & 0x3f);
736         t->time.tm_wday = bcd2bin(ds1307->regs[6] & 0x7) - 1;
737         t->time.tm_mday = bcd2bin(ds1307->regs[7] & 0x3f);
738         t->time.tm_mon = bcd2bin(ds1307->regs[8] & 0x1f) - 1;
739         t->time.tm_year = -1;
740         t->time.tm_yday = -1;
741         t->time.tm_isdst = -1;
742 
743         dev_dbg(dev, "%s, sec=%d min=%d hour=%d wday=%d mday=%d mon=%d "
744                 "enabled=%d polarity=%d irq=%d match=%d\n", __func__,
745                 t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
746                 t->time.tm_wday, t->time.tm_mday, t->time.tm_mon, t->enabled,
747                 !!(ds1307->regs[6] & MCP794XX_BIT_ALMX_POL),
748                 !!(ds1307->regs[6] & MCP794XX_BIT_ALMX_IF),
749                 (ds1307->regs[6] & MCP794XX_MSK_ALMX_MATCH) >> 4);
750 
751         return 0;
752 }
753 
754 static int mcp794xx_set_alarm(struct device *dev, struct rtc_wkalrm *t)
755 {
756         struct i2c_client *client = to_i2c_client(dev);
757         struct ds1307 *ds1307 = i2c_get_clientdata(client);
758         unsigned char *regs = ds1307->regs;
759         int ret;
760 
761         if (!test_bit(HAS_ALARM, &ds1307->flags))
762                 return -EINVAL;
763 
764         dev_dbg(dev, "%s, sec=%d min=%d hour=%d wday=%d mday=%d mon=%d "
765                 "enabled=%d pending=%d\n", __func__,
766                 t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
767                 t->time.tm_wday, t->time.tm_mday, t->time.tm_mon,
768                 t->enabled, t->pending);
769 
770         /* Read control and alarm 0 registers. */
771         ret = ds1307->read_block_data(client, MCP794XX_REG_CONTROL, 10, regs);
772         if (ret < 0)
773                 return ret;
774 
775         /* Set alarm 0, using 24-hour and day-of-month modes. */
776         regs[3] = bin2bcd(t->time.tm_sec);
777         regs[4] = bin2bcd(t->time.tm_min);
778         regs[5] = bin2bcd(t->time.tm_hour);
779         regs[6] = bin2bcd(t->time.tm_wday + 1);
780         regs[7] = bin2bcd(t->time.tm_mday);
781         regs[8] = bin2bcd(t->time.tm_mon + 1);
782 
783         /* Clear the alarm 0 interrupt flag. */
784         regs[6] &= ~MCP794XX_BIT_ALMX_IF;
785         /* Set alarm match: second, minute, hour, day, date, month. */
786         regs[6] |= MCP794XX_MSK_ALMX_MATCH;
787         /* Disable interrupt. We will not enable until completely programmed */
788         regs[0] &= ~MCP794XX_BIT_ALM0_EN;
789 
790         ret = ds1307->write_block_data(client, MCP794XX_REG_CONTROL, 10, regs);
791         if (ret < 0)
792                 return ret;
793 
794         if (!t->enabled)
795                 return 0;
796         regs[0] |= MCP794XX_BIT_ALM0_EN;
797         return i2c_smbus_write_byte_data(client, MCP794XX_REG_CONTROL, regs[0]);
798 }
799 
800 static int mcp794xx_alarm_irq_enable(struct device *dev, unsigned int enabled)
801 {
802         struct i2c_client *client = to_i2c_client(dev);
803         struct ds1307 *ds1307 = i2c_get_clientdata(client);
804         int reg;
805 
806         if (!test_bit(HAS_ALARM, &ds1307->flags))
807                 return -EINVAL;
808 
809         reg = i2c_smbus_read_byte_data(client, MCP794XX_REG_CONTROL);
810         if (reg < 0)
811                 return reg;
812 
813         if (enabled)
814                 reg |= MCP794XX_BIT_ALM0_EN;
815         else
816                 reg &= ~MCP794XX_BIT_ALM0_EN;
817 
818         return i2c_smbus_write_byte_data(client, MCP794XX_REG_CONTROL, reg);
819 }
820 
821 static const struct rtc_class_ops mcp794xx_rtc_ops = {
822         .read_time      = ds1307_get_time,
823         .set_time       = ds1307_set_time,
824         .read_alarm     = mcp794xx_read_alarm,
825         .set_alarm      = mcp794xx_set_alarm,
826         .alarm_irq_enable = mcp794xx_alarm_irq_enable,
827 };
828 
829 /*----------------------------------------------------------------------*/
830 
831 static ssize_t
832 ds1307_nvram_read(struct file *filp, struct kobject *kobj,
833                 struct bin_attribute *attr,
834                 char *buf, loff_t off, size_t count)
835 {
836         struct i2c_client       *client;
837         struct ds1307           *ds1307;
838         int                     result;
839 
840         client = kobj_to_i2c_client(kobj);
841         ds1307 = i2c_get_clientdata(client);
842 
843         result = ds1307->read_block_data(client, ds1307->nvram_offset + off,
844                                                                 count, buf);
845         if (result < 0)
846                 dev_err(&client->dev, "%s error %d\n", "nvram read", result);
847         return result;
848 }
849 
850 static ssize_t
851 ds1307_nvram_write(struct file *filp, struct kobject *kobj,
852                 struct bin_attribute *attr,
853                 char *buf, loff_t off, size_t count)
854 {
855         struct i2c_client       *client;
856         struct ds1307           *ds1307;
857         int                     result;
858 
859         client = kobj_to_i2c_client(kobj);
860         ds1307 = i2c_get_clientdata(client);
861 
862         result = ds1307->write_block_data(client, ds1307->nvram_offset + off,
863                                                                 count, buf);
864         if (result < 0) {
865                 dev_err(&client->dev, "%s error %d\n", "nvram write", result);
866                 return result;
867         }
868         return count;
869 }
870 
871 
872 /*----------------------------------------------------------------------*/
873 
874 static u8 do_trickle_setup_ds1339(struct i2c_client *client,
875                                   uint32_t ohms, bool diode)
876 {
877         u8 setup = (diode) ? DS1307_TRICKLE_CHARGER_DIODE :
878                 DS1307_TRICKLE_CHARGER_NO_DIODE;
879 
880         switch (ohms) {
881         case 250:
882                 setup |= DS1307_TRICKLE_CHARGER_250_OHM;
883                 break;
884         case 2000:
885                 setup |= DS1307_TRICKLE_CHARGER_2K_OHM;
886                 break;
887         case 4000:
888                 setup |= DS1307_TRICKLE_CHARGER_4K_OHM;
889                 break;
890         default:
891                 dev_warn(&client->dev,
892                          "Unsupported ohm value %u in dt\n", ohms);
893                 return 0;
894         }
895         return setup;
896 }
897 
898 static void ds1307_trickle_init(struct i2c_client *client,
899                                 struct chip_desc *chip)
900 {
901         uint32_t ohms = 0;
902         bool diode = true;
903 
904         if (!chip->do_trickle_setup)
905                 goto out;
906         if (device_property_read_u32(&client->dev, "trickle-resistor-ohms", &ohms))
907                 goto out;
908         if (device_property_read_bool(&client->dev, "trickle-diode-disable"))
909                 diode = false;
910         chip->trickle_charger_setup = chip->do_trickle_setup(client,
911                                                              ohms, diode);
912 out:
913         return;
914 }
915 
916 /*----------------------------------------------------------------------*/
917 
918 #ifdef CONFIG_RTC_DRV_DS1307_HWMON
919 
920 /*
921  * Temperature sensor support for ds3231 devices.
922  */
923 
924 #define DS3231_REG_TEMPERATURE  0x11
925 
926 /*
927  * A user-initiated temperature conversion is not started by this function,
928  * so the temperature is updated once every 64 seconds.
929  */
930 static int ds3231_hwmon_read_temp(struct device *dev, s32 *mC)
931 {
932         struct ds1307 *ds1307 = dev_get_drvdata(dev);
933         u8 temp_buf[2];
934         s16 temp;
935         int ret;
936 
937         ret = ds1307->read_block_data(ds1307->client, DS3231_REG_TEMPERATURE,
938                                         sizeof(temp_buf), temp_buf);
939         if (ret < 0)
940                 return ret;
941         if (ret != sizeof(temp_buf))
942                 return -EIO;
943 
944         /*
945          * Temperature is represented as a 10-bit code with a resolution of
946          * 0.25 degree celsius and encoded in two's complement format.
947          */
948         temp = (temp_buf[0] << 8) | temp_buf[1];
949         temp >>= 6;
950         *mC = temp * 250;
951 
952         return 0;
953 }
954 
955 static ssize_t ds3231_hwmon_show_temp(struct device *dev,
956                                 struct device_attribute *attr, char *buf)
957 {
958         int ret;
959         s32 temp;
960 
961         ret = ds3231_hwmon_read_temp(dev, &temp);
962         if (ret)
963                 return ret;
964 
965         return sprintf(buf, "%d\n", temp);
966 }
967 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, ds3231_hwmon_show_temp,
968                         NULL, 0);
969 
970 static struct attribute *ds3231_hwmon_attrs[] = {
971         &sensor_dev_attr_temp1_input.dev_attr.attr,
972         NULL,
973 };
974 ATTRIBUTE_GROUPS(ds3231_hwmon);
975 
976 static void ds1307_hwmon_register(struct ds1307 *ds1307)
977 {
978         struct device *dev;
979 
980         if (ds1307->type != ds_3231)
981                 return;
982 
983         dev = devm_hwmon_device_register_with_groups(&ds1307->client->dev,
984                                                 ds1307->client->name,
985                                                 ds1307, ds3231_hwmon_groups);
986         if (IS_ERR(dev)) {
987                 dev_warn(&ds1307->client->dev,
988                         "unable to register hwmon device %ld\n", PTR_ERR(dev));
989         }
990 }
991 
992 #else
993 
994 static void ds1307_hwmon_register(struct ds1307 *ds1307)
995 {
996 }
997 
998 #endif /* CONFIG_RTC_DRV_DS1307_HWMON */
999 
1000 /*----------------------------------------------------------------------*/
1001 
1002 /*
1003  * Square-wave output support for DS3231
1004  * Datasheet: https://datasheets.maximintegrated.com/en/ds/DS3231.pdf
1005  */
1006 #ifdef CONFIG_COMMON_CLK
1007 
1008 enum {
1009         DS3231_CLK_SQW = 0,
1010         DS3231_CLK_32KHZ,
1011 };
1012 
1013 #define clk_sqw_to_ds1307(clk)  \
1014         container_of(clk, struct ds1307, clks[DS3231_CLK_SQW])
1015 #define clk_32khz_to_ds1307(clk)        \
1016         container_of(clk, struct ds1307, clks[DS3231_CLK_32KHZ])
1017 
1018 static int ds3231_clk_sqw_rates[] = {
1019         1,
1020         1024,
1021         4096,
1022         8192,
1023 };
1024 
1025 static int ds1337_write_control(struct ds1307 *ds1307, u8 mask, u8 value)
1026 {
1027         struct i2c_client *client = ds1307->client;
1028         struct mutex *lock = &ds1307->rtc->ops_lock;
1029         int control;
1030         int ret;
1031 
1032         mutex_lock(lock);
1033 
1034         control = i2c_smbus_read_byte_data(client, DS1337_REG_CONTROL);
1035         if (control < 0) {
1036                 ret = control;
1037                 goto out;
1038         }
1039 
1040         control &= ~mask;
1041         control |= value;
1042 
1043         ret = i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL, control);
1044 out:
1045         mutex_unlock(lock);
1046 
1047         return ret;
1048 }
1049 
1050 static unsigned long ds3231_clk_sqw_recalc_rate(struct clk_hw *hw,
1051                                                 unsigned long parent_rate)
1052 {
1053         struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
1054         int control;
1055         int rate_sel = 0;
1056 
1057         control = i2c_smbus_read_byte_data(ds1307->client, DS1337_REG_CONTROL);
1058         if (control < 0)
1059                 return control;
1060         if (control & DS1337_BIT_RS1)
1061                 rate_sel += 1;
1062         if (control & DS1337_BIT_RS2)
1063                 rate_sel += 2;
1064 
1065         return ds3231_clk_sqw_rates[rate_sel];
1066 }
1067 
1068 static long ds3231_clk_sqw_round_rate(struct clk_hw *hw, unsigned long rate,
1069                                         unsigned long *prate)
1070 {
1071         int i;
1072 
1073         for (i = ARRAY_SIZE(ds3231_clk_sqw_rates) - 1; i >= 0; i--) {
1074                 if (ds3231_clk_sqw_rates[i] <= rate)
1075                         return ds3231_clk_sqw_rates[i];
1076         }
1077 
1078         return 0;
1079 }
1080 
1081 static int ds3231_clk_sqw_set_rate(struct clk_hw *hw, unsigned long rate,
1082                                         unsigned long parent_rate)
1083 {
1084         struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
1085         int control = 0;
1086         int rate_sel;
1087 
1088         for (rate_sel = 0; rate_sel < ARRAY_SIZE(ds3231_clk_sqw_rates);
1089                         rate_sel++) {
1090                 if (ds3231_clk_sqw_rates[rate_sel] == rate)
1091                         break;
1092         }
1093 
1094         if (rate_sel == ARRAY_SIZE(ds3231_clk_sqw_rates))
1095                 return -EINVAL;
1096 
1097         if (rate_sel & 1)
1098                 control |= DS1337_BIT_RS1;
1099         if (rate_sel & 2)
1100                 control |= DS1337_BIT_RS2;
1101 
1102         return ds1337_write_control(ds1307, DS1337_BIT_RS1 | DS1337_BIT_RS2,
1103                                 control);
1104 }
1105 
1106 static int ds3231_clk_sqw_prepare(struct clk_hw *hw)
1107 {
1108         struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
1109 
1110         return ds1337_write_control(ds1307, DS1337_BIT_INTCN, 0);
1111 }
1112 
1113 static void ds3231_clk_sqw_unprepare(struct clk_hw *hw)
1114 {
1115         struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
1116 
1117         ds1337_write_control(ds1307, DS1337_BIT_INTCN, DS1337_BIT_INTCN);
1118 }
1119 
1120 static int ds3231_clk_sqw_is_prepared(struct clk_hw *hw)
1121 {
1122         struct ds1307 *ds1307 = clk_sqw_to_ds1307(hw);
1123         int control;
1124 
1125         control = i2c_smbus_read_byte_data(ds1307->client, DS1337_REG_CONTROL);
1126         if (control < 0)
1127                 return control;
1128 
1129         return !(control & DS1337_BIT_INTCN);
1130 }
1131 
1132 static const struct clk_ops ds3231_clk_sqw_ops = {
1133         .prepare = ds3231_clk_sqw_prepare,
1134         .unprepare = ds3231_clk_sqw_unprepare,
1135         .is_prepared = ds3231_clk_sqw_is_prepared,
1136         .recalc_rate = ds3231_clk_sqw_recalc_rate,
1137         .round_rate = ds3231_clk_sqw_round_rate,
1138         .set_rate = ds3231_clk_sqw_set_rate,
1139 };
1140 
1141 static unsigned long ds3231_clk_32khz_recalc_rate(struct clk_hw *hw,
1142                                                 unsigned long parent_rate)
1143 {
1144         return 32768;
1145 }
1146 
1147 static int ds3231_clk_32khz_control(struct ds1307 *ds1307, bool enable)
1148 {
1149         struct i2c_client *client = ds1307->client;
1150         struct mutex *lock = &ds1307->rtc->ops_lock;
1151         int status;
1152         int ret;
1153 
1154         mutex_lock(lock);
1155 
1156         status = i2c_smbus_read_byte_data(client, DS1337_REG_STATUS);
1157         if (status < 0) {
1158                 ret = status;
1159                 goto out;
1160         }
1161 
1162         if (enable)
1163                 status |= DS3231_BIT_EN32KHZ;
1164         else
1165                 status &= ~DS3231_BIT_EN32KHZ;
1166 
1167         ret = i2c_smbus_write_byte_data(client, DS1337_REG_STATUS, status);
1168 out:
1169         mutex_unlock(lock);
1170 
1171         return ret;
1172 }
1173 
1174 static int ds3231_clk_32khz_prepare(struct clk_hw *hw)
1175 {
1176         struct ds1307 *ds1307 = clk_32khz_to_ds1307(hw);
1177 
1178         return ds3231_clk_32khz_control(ds1307, true);
1179 }
1180 
1181 static void ds3231_clk_32khz_unprepare(struct clk_hw *hw)
1182 {
1183         struct ds1307 *ds1307 = clk_32khz_to_ds1307(hw);
1184 
1185         ds3231_clk_32khz_control(ds1307, false);
1186 }
1187 
1188 static int ds3231_clk_32khz_is_prepared(struct clk_hw *hw)
1189 {
1190         struct ds1307 *ds1307 = clk_32khz_to_ds1307(hw);
1191         int status;
1192 
1193         status = i2c_smbus_read_byte_data(ds1307->client, DS1337_REG_STATUS);
1194         if (status < 0)
1195                 return status;
1196 
1197         return !!(status & DS3231_BIT_EN32KHZ);
1198 }
1199 
1200 static const struct clk_ops ds3231_clk_32khz_ops = {
1201         .prepare = ds3231_clk_32khz_prepare,
1202         .unprepare = ds3231_clk_32khz_unprepare,
1203         .is_prepared = ds3231_clk_32khz_is_prepared,
1204         .recalc_rate = ds3231_clk_32khz_recalc_rate,
1205 };
1206 
1207 static struct clk_init_data ds3231_clks_init[] = {
1208         [DS3231_CLK_SQW] = {
1209                 .name = "ds3231_clk_sqw",
1210                 .ops = &ds3231_clk_sqw_ops,
1211         },
1212         [DS3231_CLK_32KHZ] = {
1213                 .name = "ds3231_clk_32khz",
1214                 .ops = &ds3231_clk_32khz_ops,
1215         },
1216 };
1217 
1218 static int ds3231_clks_register(struct ds1307 *ds1307)
1219 {
1220         struct i2c_client *client = ds1307->client;
1221         struct device_node *node = client->dev.of_node;
1222         struct clk_onecell_data *onecell;
1223         int i;
1224 
1225         onecell = devm_kzalloc(&client->dev, sizeof(*onecell), GFP_KERNEL);
1226         if (!onecell)
1227                 return -ENOMEM;
1228 
1229         onecell->clk_num = ARRAY_SIZE(ds3231_clks_init);
1230         onecell->clks = devm_kcalloc(&client->dev, onecell->clk_num,
1231                                         sizeof(onecell->clks[0]), GFP_KERNEL);
1232         if (!onecell->clks)
1233                 return -ENOMEM;
1234 
1235         for (i = 0; i < ARRAY_SIZE(ds3231_clks_init); i++) {
1236                 struct clk_init_data init = ds3231_clks_init[i];
1237 
1238                 /*
1239                  * Interrupt signal due to alarm conditions and square-wave
1240                  * output share same pin, so don't initialize both.
1241                  */
1242                 if (i == DS3231_CLK_SQW && test_bit(HAS_ALARM, &ds1307->flags))
1243                         continue;
1244 
1245                 /* optional override of the clockname */
1246                 of_property_read_string_index(node, "clock-output-names", i,
1247                                                 &init.name);
1248                 ds1307->clks[i].init = &init;
1249 
1250                 onecell->clks[i] = devm_clk_register(&client->dev,
1251                                                         &ds1307->clks[i]);
1252                 if (IS_ERR(onecell->clks[i]))
1253                         return PTR_ERR(onecell->clks[i]);
1254         }
1255 
1256         if (!node)
1257                 return 0;
1258 
1259         of_clk_add_provider(node, of_clk_src_onecell_get, onecell);
1260 
1261         return 0;
1262 }
1263 
1264 static void ds1307_clks_register(struct ds1307 *ds1307)
1265 {
1266         int ret;
1267 
1268         if (ds1307->type != ds_3231)
1269                 return;
1270 
1271         ret = ds3231_clks_register(ds1307);
1272         if (ret) {
1273                 dev_warn(&ds1307->client->dev,
1274                         "unable to register clock device %d\n", ret);
1275         }
1276 }
1277 
1278 #else
1279 
1280 static void ds1307_clks_register(struct ds1307 *ds1307)
1281 {
1282 }
1283 
1284 #endif /* CONFIG_COMMON_CLK */
1285 
1286 static int ds1307_probe(struct i2c_client *client,
1287                         const struct i2c_device_id *id)
1288 {
1289         struct ds1307           *ds1307;
1290         int                     err = -ENODEV;
1291         int                     tmp, wday;
1292         struct chip_desc        *chip;
1293         struct i2c_adapter      *adapter = to_i2c_adapter(client->dev.parent);
1294         bool                    want_irq = false;
1295         bool                    ds1307_can_wakeup_device = false;
1296         unsigned char           *buf;
1297         struct ds1307_platform_data *pdata = dev_get_platdata(&client->dev);
1298         struct rtc_time         tm;
1299         unsigned long           timestamp;
1300 
1301         irq_handler_t   irq_handler = ds1307_irq;
1302 
1303         static const int        bbsqi_bitpos[] = {
1304                 [ds_1337] = 0,
1305                 [ds_1339] = DS1339_BIT_BBSQI,
1306                 [ds_3231] = DS3231_BIT_BBSQW,
1307         };
1308         const struct rtc_class_ops *rtc_ops = &ds13xx_rtc_ops;
1309 
1310         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)
1311             && !i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
1312                 return -EIO;
1313 
1314         ds1307 = devm_kzalloc(&client->dev, sizeof(struct ds1307), GFP_KERNEL);
1315         if (!ds1307)
1316                 return -ENOMEM;
1317 
1318         i2c_set_clientdata(client, ds1307);
1319 
1320         ds1307->client  = client;
1321         if (id) {
1322                 chip = &chips[id->driver_data];
1323                 ds1307->type = id->driver_data;
1324         } else {
1325                 const struct acpi_device_id *acpi_id;
1326 
1327                 acpi_id = acpi_match_device(ACPI_PTR(ds1307_acpi_ids),
1328                                             &client->dev);
1329                 if (!acpi_id)
1330                         return -ENODEV;
1331                 chip = &chips[acpi_id->driver_data];
1332                 ds1307->type = acpi_id->driver_data;
1333         }
1334 
1335         if (!pdata)
1336                 ds1307_trickle_init(client, chip);
1337         else if (pdata->trickle_charger_setup)
1338                 chip->trickle_charger_setup = pdata->trickle_charger_setup;
1339 
1340         if (chip->trickle_charger_setup && chip->trickle_charger_reg) {
1341                 dev_dbg(&client->dev, "writing trickle charger info 0x%x to 0x%x\n",
1342                     DS13XX_TRICKLE_CHARGER_MAGIC | chip->trickle_charger_setup,
1343                     chip->trickle_charger_reg);
1344                 i2c_smbus_write_byte_data(client, chip->trickle_charger_reg,
1345                     DS13XX_TRICKLE_CHARGER_MAGIC |
1346                     chip->trickle_charger_setup);
1347         }
1348 
1349         buf = ds1307->regs;
1350         if (i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) {
1351                 ds1307->read_block_data = ds1307_native_smbus_read_block_data;
1352                 ds1307->write_block_data = ds1307_native_smbus_write_block_data;
1353         } else {
1354                 ds1307->read_block_data = ds1307_read_block_data;
1355                 ds1307->write_block_data = ds1307_write_block_data;
1356         }
1357 
1358 #ifdef CONFIG_OF
1359 /*
1360  * For devices with no IRQ directly connected to the SoC, the RTC chip
1361  * can be forced as a wakeup source by stating that explicitly in
1362  * the device's .dts file using the "wakeup-source" boolean property.
1363  * If the "wakeup-source" property is set, don't request an IRQ.
1364  * This will guarantee the 'wakealarm' sysfs entry is available on the device,
1365  * if supported by the RTC.
1366  */
1367         if (of_property_read_bool(client->dev.of_node, "wakeup-source")) {
1368                 ds1307_can_wakeup_device = true;
1369         }
1370         /* Intersil ISL12057 DT backward compatibility */
1371         if (of_property_read_bool(client->dev.of_node,
1372                                   "isil,irq2-can-wakeup-machine")) {
1373                 ds1307_can_wakeup_device = true;
1374         }
1375 #endif
1376 
1377         switch (ds1307->type) {
1378         case ds_1337:
1379         case ds_1339:
1380         case ds_3231:
1381                 /* get registers that the "rtc" read below won't read... */
1382                 tmp = ds1307->read_block_data(ds1307->client,
1383                                 DS1337_REG_CONTROL, 2, buf);
1384                 if (tmp != 2) {
1385                         dev_dbg(&client->dev, "read error %d\n", tmp);
1386                         err = -EIO;
1387                         goto exit;
1388                 }
1389 
1390                 /* oscillator off?  turn it on, so clock can tick. */
1391                 if (ds1307->regs[0] & DS1337_BIT_nEOSC)
1392                         ds1307->regs[0] &= ~DS1337_BIT_nEOSC;
1393 
1394                 /*
1395                  * Using IRQ or defined as wakeup-source?
1396                  * Disable the square wave and both alarms.
1397                  * For some variants, be sure alarms can trigger when we're
1398                  * running on Vbackup (BBSQI/BBSQW)
1399                  */
1400                 if (chip->alarm && (ds1307->client->irq > 0 ||
1401                                                 ds1307_can_wakeup_device)) {
1402                         ds1307->regs[0] |= DS1337_BIT_INTCN
1403                                         | bbsqi_bitpos[ds1307->type];
1404                         ds1307->regs[0] &= ~(DS1337_BIT_A2IE | DS1337_BIT_A1IE);
1405 
1406                         want_irq = true;
1407                 }
1408 
1409                 i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL,
1410                                                         ds1307->regs[0]);
1411 
1412                 /* oscillator fault?  clear flag, and warn */
1413                 if (ds1307->regs[1] & DS1337_BIT_OSF) {
1414                         i2c_smbus_write_byte_data(client, DS1337_REG_STATUS,
1415                                 ds1307->regs[1] & ~DS1337_BIT_OSF);
1416                         dev_warn(&client->dev, "SET TIME!\n");
1417                 }
1418                 break;
1419 
1420         case rx_8025:
1421                 tmp = i2c_smbus_read_i2c_block_data(ds1307->client,
1422                                 RX8025_REG_CTRL1 << 4 | 0x08, 2, buf);
1423                 if (tmp != 2) {
1424                         dev_dbg(&client->dev, "read error %d\n", tmp);
1425                         err = -EIO;
1426                         goto exit;
1427                 }
1428 
1429                 /* oscillator off?  turn it on, so clock can tick. */
1430                 if (!(ds1307->regs[1] & RX8025_BIT_XST)) {
1431                         ds1307->regs[1] |= RX8025_BIT_XST;
1432                         i2c_smbus_write_byte_data(client,
1433                                                   RX8025_REG_CTRL2 << 4 | 0x08,
1434                                                   ds1307->regs[1]);
1435                         dev_warn(&client->dev,
1436                                  "oscillator stop detected - SET TIME!\n");
1437                 }
1438 
1439                 if (ds1307->regs[1] & RX8025_BIT_PON) {
1440                         ds1307->regs[1] &= ~RX8025_BIT_PON;
1441                         i2c_smbus_write_byte_data(client,
1442                                                   RX8025_REG_CTRL2 << 4 | 0x08,
1443                                                   ds1307->regs[1]);
1444                         dev_warn(&client->dev, "power-on detected\n");
1445                 }
1446 
1447                 if (ds1307->regs[1] & RX8025_BIT_VDET) {
1448                         ds1307->regs[1] &= ~RX8025_BIT_VDET;
1449                         i2c_smbus_write_byte_data(client,
1450                                                   RX8025_REG_CTRL2 << 4 | 0x08,
1451                                                   ds1307->regs[1]);
1452                         dev_warn(&client->dev, "voltage drop detected\n");
1453                 }
1454 
1455                 /* make sure we are running in 24hour mode */
1456                 if (!(ds1307->regs[0] & RX8025_BIT_2412)) {
1457                         u8 hour;
1458 
1459                         /* switch to 24 hour mode */
1460                         i2c_smbus_write_byte_data(client,
1461                                                   RX8025_REG_CTRL1 << 4 | 0x08,
1462                                                   ds1307->regs[0] |
1463                                                   RX8025_BIT_2412);
1464 
1465                         tmp = i2c_smbus_read_i2c_block_data(ds1307->client,
1466                                         RX8025_REG_CTRL1 << 4 | 0x08, 2, buf);
1467                         if (tmp != 2) {
1468                                 dev_dbg(&client->dev, "read error %d\n", tmp);
1469                                 err = -EIO;
1470                                 goto exit;
1471                         }
1472 
1473                         /* correct hour */
1474                         hour = bcd2bin(ds1307->regs[DS1307_REG_HOUR]);
1475                         if (hour == 12)
1476                                 hour = 0;
1477                         if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
1478                                 hour += 12;
1479 
1480                         i2c_smbus_write_byte_data(client,
1481                                                   DS1307_REG_HOUR << 4 | 0x08,
1482                                                   hour);
1483                 }
1484                 break;
1485         case ds_1388:
1486                 ds1307->offset = 1; /* Seconds starts at 1 */
1487                 break;
1488         case mcp794xx:
1489                 rtc_ops = &mcp794xx_rtc_ops;
1490                 if (ds1307->client->irq > 0 && chip->alarm) {
1491                         irq_handler = mcp794xx_irq;
1492                         want_irq = true;
1493                 }
1494                 break;
1495         default:
1496                 break;
1497         }
1498 
1499 read_rtc:
1500         /* read RTC registers */
1501         tmp = ds1307->read_block_data(ds1307->client, ds1307->offset, 8, buf);
1502         if (tmp != 8) {
1503                 dev_dbg(&client->dev, "read error %d\n", tmp);
1504                 err = -EIO;
1505                 goto exit;
1506         }
1507 
1508         /*
1509          * minimal sanity checking; some chips (like DS1340) don't
1510          * specify the extra bits as must-be-zero, but there are
1511          * still a few values that are clearly out-of-range.
1512          */
1513         tmp = ds1307->regs[DS1307_REG_SECS];
1514         switch (ds1307->type) {
1515         case ds_1307:
1516         case m41t00:
1517                 /* clock halted?  turn it on, so clock can tick. */
1518                 if (tmp & DS1307_BIT_CH) {
1519                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
1520                         dev_warn(&client->dev, "SET TIME!\n");
1521                         goto read_rtc;
1522                 }
1523                 break;
1524         case ds_1338:
1525                 /* clock halted?  turn it on, so clock can tick. */
1526                 if (tmp & DS1307_BIT_CH)
1527                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
1528 
1529                 /* oscillator fault?  clear flag, and warn */
1530                 if (ds1307->regs[DS1307_REG_CONTROL] & DS1338_BIT_OSF) {
1531                         i2c_smbus_write_byte_data(client, DS1307_REG_CONTROL,
1532                                         ds1307->regs[DS1307_REG_CONTROL]
1533                                         & ~DS1338_BIT_OSF);
1534                         dev_warn(&client->dev, "SET TIME!\n");
1535                         goto read_rtc;
1536                 }
1537                 break;
1538         case ds_1340:
1539                 /* clock halted?  turn it on, so clock can tick. */
1540                 if (tmp & DS1340_BIT_nEOSC)
1541                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
1542 
1543                 tmp = i2c_smbus_read_byte_data(client, DS1340_REG_FLAG);
1544                 if (tmp < 0) {
1545                         dev_dbg(&client->dev, "read error %d\n", tmp);
1546                         err = -EIO;
1547                         goto exit;
1548                 }
1549 
1550                 /* oscillator fault?  clear flag, and warn */
1551                 if (tmp & DS1340_BIT_OSF) {
1552                         i2c_smbus_write_byte_data(client, DS1340_REG_FLAG, 0);
1553                         dev_warn(&client->dev, "SET TIME!\n");
1554                 }
1555                 break;
1556         case mcp794xx:
1557                 /* make sure that the backup battery is enabled */
1558                 if (!(ds1307->regs[DS1307_REG_WDAY] & MCP794XX_BIT_VBATEN)) {
1559                         i2c_smbus_write_byte_data(client, DS1307_REG_WDAY,
1560                                         ds1307->regs[DS1307_REG_WDAY]
1561                                         | MCP794XX_BIT_VBATEN);
1562                 }
1563 
1564                 /* clock halted?  turn it on, so clock can tick. */
1565                 if (!(tmp & MCP794XX_BIT_ST)) {
1566                         i2c_smbus_write_byte_data(client, DS1307_REG_SECS,
1567                                         MCP794XX_BIT_ST);
1568                         dev_warn(&client->dev, "SET TIME!\n");
1569                         goto read_rtc;
1570                 }
1571 
1572                 break;
1573         default:
1574                 break;
1575         }
1576 
1577         tmp = ds1307->regs[DS1307_REG_HOUR];
1578         switch (ds1307->type) {
1579         case ds_1340:
1580         case m41t00:
1581                 /*
1582                  * NOTE: ignores century bits; fix before deploying
1583                  * systems that will run through year 2100.
1584                  */
1585                 break;
1586         case rx_8025:
1587                 break;
1588         default:
1589                 if (!(tmp & DS1307_BIT_12HR))
1590                         break;
1591 
1592                 /*
1593                  * Be sure we're in 24 hour mode.  Multi-master systems
1594                  * take note...
1595                  */
1596                 tmp = bcd2bin(tmp & 0x1f);
1597                 if (tmp == 12)
1598                         tmp = 0;
1599                 if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
1600                         tmp += 12;
1601                 i2c_smbus_write_byte_data(client,
1602                                 ds1307->offset + DS1307_REG_HOUR,
1603                                 bin2bcd(tmp));
1604         }
1605 
1606         /*
1607          * Some IPs have weekday reset value = 0x1 which might not correct
1608          * hence compute the wday using the current date/month/year values
1609          */
1610         ds1307_get_time(&client->dev, &tm);
1611         wday = tm.tm_wday;
1612         timestamp = rtc_tm_to_time64(&tm);
1613         rtc_time64_to_tm(timestamp, &tm);
1614 
1615         /*
1616          * Check if reset wday is different from the computed wday
1617          * If different then set the wday which we computed using
1618          * timestamp
1619          */
1620         if (wday != tm.tm_wday) {
1621                 wday = i2c_smbus_read_byte_data(client, MCP794XX_REG_WEEKDAY);
1622                 wday = wday & ~MCP794XX_REG_WEEKDAY_WDAY_MASK;
1623                 wday = wday | (tm.tm_wday + 1);
1624                 i2c_smbus_write_byte_data(client, MCP794XX_REG_WEEKDAY, wday);
1625         }
1626 
1627         if (want_irq) {
1628                 device_set_wakeup_capable(&client->dev, true);
1629                 set_bit(HAS_ALARM, &ds1307->flags);
1630         }
1631         ds1307->rtc = devm_rtc_device_register(&client->dev, client->name,
1632                                 rtc_ops, THIS_MODULE);
1633         if (IS_ERR(ds1307->rtc)) {
1634                 return PTR_ERR(ds1307->rtc);
1635         }
1636 
1637         if (ds1307_can_wakeup_device && ds1307->client->irq <= 0) {
1638                 /* Disable request for an IRQ */
1639                 want_irq = false;
1640                 dev_info(&client->dev, "'wakeup-source' is set, request for an IRQ is disabled!\n");
1641                 /* We cannot support UIE mode if we do not have an IRQ line */
1642                 ds1307->rtc->uie_unsupported = 1;
1643         }
1644 
1645         if (want_irq) {
1646                 err = devm_request_threaded_irq(&client->dev,
1647                                                 client->irq, NULL, irq_handler,
1648                                                 IRQF_SHARED | IRQF_ONESHOT,
1649                                                 ds1307->rtc->name, client);
1650                 if (err) {
1651                         client->irq = 0;
1652                         device_set_wakeup_capable(&client->dev, false);
1653                         clear_bit(HAS_ALARM, &ds1307->flags);
1654                         dev_err(&client->dev, "unable to request IRQ!\n");
1655                 } else
1656                         dev_dbg(&client->dev, "got IRQ %d\n", client->irq);
1657         }
1658 
1659         if (chip->nvram_size) {
1660 
1661                 ds1307->nvram = devm_kzalloc(&client->dev,
1662                                         sizeof(struct bin_attribute),
1663                                         GFP_KERNEL);
1664                 if (!ds1307->nvram) {
1665                         dev_err(&client->dev, "cannot allocate memory for nvram sysfs\n");
1666                 } else {
1667 
1668                         ds1307->nvram->attr.name = "nvram";
1669                         ds1307->nvram->attr.mode = S_IRUGO | S_IWUSR;
1670 
1671                         sysfs_bin_attr_init(ds1307->nvram);
1672 
1673                         ds1307->nvram->read = ds1307_nvram_read;
1674                         ds1307->nvram->write = ds1307_nvram_write;
1675                         ds1307->nvram->size = chip->nvram_size;
1676                         ds1307->nvram_offset = chip->nvram_offset;
1677 
1678                         err = sysfs_create_bin_file(&client->dev.kobj,
1679                                                     ds1307->nvram);
1680                         if (err) {
1681                                 dev_err(&client->dev,
1682                                         "unable to create sysfs file: %s\n",
1683                                         ds1307->nvram->attr.name);
1684                         } else {
1685                                 set_bit(HAS_NVRAM, &ds1307->flags);
1686                                 dev_info(&client->dev, "%zu bytes nvram\n",
1687                                          ds1307->nvram->size);
1688                         }
1689                 }
1690         }
1691 
1692         ds1307_hwmon_register(ds1307);
1693         ds1307_clks_register(ds1307);
1694 
1695         return 0;
1696 
1697 exit:
1698         return err;
1699 }
1700 
1701 static int ds1307_remove(struct i2c_client *client)
1702 {
1703         struct ds1307 *ds1307 = i2c_get_clientdata(client);
1704 
1705         if (test_and_clear_bit(HAS_NVRAM, &ds1307->flags))
1706                 sysfs_remove_bin_file(&client->dev.kobj, ds1307->nvram);
1707 
1708         return 0;
1709 }
1710 
1711 static struct i2c_driver ds1307_driver = {
1712         .driver = {
1713                 .name   = "rtc-ds1307",
1714                 .acpi_match_table = ACPI_PTR(ds1307_acpi_ids),
1715         },
1716         .probe          = ds1307_probe,
1717         .remove         = ds1307_remove,
1718         .id_table       = ds1307_id,
1719 };
1720 
1721 module_i2c_driver(ds1307_driver);
1722 
1723 MODULE_DESCRIPTION("RTC driver for DS1307 and similar chips");
1724 MODULE_LICENSE("GPL");
1725 

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