drivers/rtc/rtc-ds1343.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /* rtc-ds1343.c
   3  *
   4  * Driver for Dallas Semiconductor DS1343 Low Current, SPI Compatible
   5  * Real Time Clock
   6  *
   7  * Author : Raghavendra Chandra Ganiga <ravi23ganiga@gmail.com>
   8  *          Ankur Srivastava <sankurece@gmail.com> : DS1343 Nvram Support
   9  */
  10
  11 #include <linux/init.h>
  12 #include <linux/module.h>
  13 #include <linux/interrupt.h>
  14 #include <linux/device.h>
  15 #include <linux/spi/spi.h>
  16 #include <linux/regmap.h>
  17 #include <linux/rtc.h>
  18 #include <linux/bcd.h>
  19 #include <linux/pm.h>
  20 #include <linux/pm_wakeirq.h>
  21 #include <linux/slab.h>
  22
  23 #define DALLAS_MAXIM_DS1343     0
  24 #define DALLAS_MAXIM_DS1344     1
  25
  26 /* RTC DS1343 Registers */
  27 #define DS1343_SECONDS_REG      0x00
  28 #define DS1343_MINUTES_REG      0x01
  29 #define DS1343_HOURS_REG        0x02
  30 #define DS1343_DAY_REG          0x03
  31 #define DS1343_DATE_REG         0x04
  32 #define DS1343_MONTH_REG        0x05
  33 #define DS1343_YEAR_REG         0x06
  34 #define DS1343_ALM0_SEC_REG     0x07
  35 #define DS1343_ALM0_MIN_REG     0x08
  36 #define DS1343_ALM0_HOUR_REG    0x09
  37 #define DS1343_ALM0_DAY_REG     0x0A
  38 #define DS1343_ALM1_SEC_REG     0x0B
  39 #define DS1343_ALM1_MIN_REG     0x0C
  40 #define DS1343_ALM1_HOUR_REG    0x0D
  41 #define DS1343_ALM1_DAY_REG     0x0E
  42 #define DS1343_CONTROL_REG      0x0F
  43 #define DS1343_STATUS_REG       0x10
  44 #define DS1343_TRICKLE_REG      0x11
  45 #define DS1343_NVRAM            0x20
  46
  47 #define DS1343_NVRAM_LEN        96
  48
  49 /* DS1343 Control Registers bits */
  50 #define DS1343_EOSC             0x80
  51 #define DS1343_DOSF             0x20
  52 #define DS1343_EGFIL            0x10
  53 #define DS1343_SQW              0x08
  54 #define DS1343_INTCN            0x04
  55 #define DS1343_A1IE             0x02
  56 #define DS1343_A0IE             0x01
  57
  58 /* DS1343 Status Registers bits */
  59 #define DS1343_OSF              0x80
  60 #define DS1343_IRQF1            0x02
  61 #define DS1343_IRQF0            0x01
  62
  63 /* DS1343 Trickle Charger Registers bits */
  64 #define DS1343_TRICKLE_MAGIC    0xa0
  65 #define DS1343_TRICKLE_DS1      0x08
  66 #define DS1343_TRICKLE_1K       0x01
  67 #define DS1343_TRICKLE_2K       0x02
  68 #define DS1343_TRICKLE_4K       0x03
  69
  70 static const struct spi_device_id ds1343_id[] = {
  71         { "ds1343", DALLAS_MAXIM_DS1343 },
  72         { "ds1344", DALLAS_MAXIM_DS1344 },
  73         { }
  74 };
  75 MODULE_DEVICE_TABLE(spi, ds1343_id);
  76
  77 struct ds1343_priv {
  78         struct rtc_device *rtc;
  79         struct regmap *map;
  80         int irq;
  81 };
  82
  83 static ssize_t ds1343_show_glitchfilter(struct device *dev,
  84                                 struct device_attribute *attr, char *buf)
  85 {
  86         struct ds1343_priv *priv = dev_get_drvdata(dev->parent);
  87         int glitch_filt_status, data;
  88         int res;
  89
  90         res = regmap_read(priv->map, DS1343_CONTROL_REG, &data);
  91         if (res)
  92                 return res;
  93
  94         glitch_filt_status = !!(data & DS1343_EGFIL);
  95
  96         if (glitch_filt_status)
  97                 return sprintf(buf, "enabled\n");
  98         else
  99                 return sprintf(buf, "disabled\n");
 100 }
 101
 102 static ssize_t ds1343_store_glitchfilter(struct device *dev,
 103                                         struct device_attribute *attr,
 104                                         const char *buf, size_t count)
 105 {
 106         struct ds1343_priv *priv = dev_get_drvdata(dev->parent);
 107         int data = 0;
 108         int res;
 109
 110         if (strncmp(buf, "enabled", 7) == 0)
 111                 data = DS1343_EGFIL;
 112         else if (strncmp(buf, "disabled", 8))
 113                 return -EINVAL;
 114
 115         res = regmap_update_bits(priv->map, DS1343_CONTROL_REG,
 116                                  DS1343_EGFIL, data);
 117         if (res)
 118                 return res;
 119
 120         return count;
 121 }
 122
 123 static DEVICE_ATTR(glitch_filter, S_IRUGO | S_IWUSR, ds1343_show_glitchfilter,
 124                         ds1343_store_glitchfilter);
 125
 126 static int ds1343_nvram_write(void *priv, unsigned int off, void *val,
 127                               size_t bytes)
 128 {
 129         struct ds1343_priv *ds1343 = priv;
 130
 131         return regmap_bulk_write(ds1343->map, DS1343_NVRAM + off, val, bytes);
 132 }
 133
 134 static int ds1343_nvram_read(void *priv, unsigned int off, void *val,
 135                              size_t bytes)
 136 {
 137         struct ds1343_priv *ds1343 = priv;
 138
 139         return regmap_bulk_read(ds1343->map, DS1343_NVRAM + off, val, bytes);
 140 }
 141
 142 static ssize_t ds1343_show_tricklecharger(struct device *dev,
 143                                 struct device_attribute *attr, char *buf)
 144 {
 145         struct ds1343_priv *priv = dev_get_drvdata(dev->parent);
 146         int res, data;
 147         char *diodes = "disabled", *resistors = " ";
 148
 149         res = regmap_read(priv->map, DS1343_TRICKLE_REG, &data);
 150         if (res)
 151                 return res;
 152
 153         if ((data & 0xf0) == DS1343_TRICKLE_MAGIC) {
 154                 switch (data & 0x0c) {
 155                 case DS1343_TRICKLE_DS1:
 156                         diodes = "one diode,";
 157                         break;
 158
 159                 default:
 160                         diodes = "no diode,";
 161                         break;
 162                 }
 163
 164                 switch (data & 0x03) {
 165                 case DS1343_TRICKLE_1K:
 166                         resistors = "1k Ohm";
 167                         break;
 168
 169                 case DS1343_TRICKLE_2K:
 170                         resistors = "2k Ohm";
 171                         break;
 172
 173                 case DS1343_TRICKLE_4K:
 174                         resistors = "4k Ohm";
 175                         break;
 176
 177                 default:
 178                         diodes = "disabled";
 179                         break;
 180                 }
 181         }
 182
 183         return sprintf(buf, "%s %s\n", diodes, resistors);
 184 }
 185
 186 static DEVICE_ATTR(trickle_charger, S_IRUGO, ds1343_show_tricklecharger, NULL);
 187
 188 static struct attribute *ds1343_attrs[] = {
 189         &dev_attr_glitch_filter.attr,
 190         &dev_attr_trickle_charger.attr,
 191         NULL
 192 };
 193
 194 static const struct attribute_group ds1343_attr_group = {
 195         .attrs  = ds1343_attrs,
 196 };
 197
 198 static int ds1343_read_time(struct device *dev, struct rtc_time *dt)
 199 {
 200         struct ds1343_priv *priv = dev_get_drvdata(dev);
 201         unsigned char buf[7];
 202         int res;
 203
 204         res = regmap_bulk_read(priv->map, DS1343_SECONDS_REG, buf, 7);
 205         if (res)
 206                 return res;
 207
 208         dt->tm_sec      = bcd2bin(buf[0]);
 209         dt->tm_min      = bcd2bin(buf[1]);
 210         dt->tm_hour     = bcd2bin(buf[2] & 0x3F);
 211         dt->tm_wday     = bcd2bin(buf[3]) - 1;
 212         dt->tm_mday     = bcd2bin(buf[4]);
 213         dt->tm_mon      = bcd2bin(buf[5] & 0x1F) - 1;
 214         dt->tm_year     = bcd2bin(buf[6]) + 100; /* year offset from 1900 */
 215
 216         return 0;
 217 }
 218
 219 static int ds1343_set_time(struct device *dev, struct rtc_time *dt)
 220 {
 221         struct ds1343_priv *priv = dev_get_drvdata(dev);
 222         u8 buf[7];
 223
 224         buf[0] = bin2bcd(dt->tm_sec);
 225         buf[1] = bin2bcd(dt->tm_min);
 226         buf[2] = bin2bcd(dt->tm_hour) & 0x3F;
 227         buf[3] = bin2bcd(dt->tm_wday + 1);
 228         buf[4] = bin2bcd(dt->tm_mday);
 229         buf[5] = bin2bcd(dt->tm_mon + 1);
 230         buf[6] = bin2bcd(dt->tm_year - 100);
 231
 232         return regmap_bulk_write(priv->map, DS1343_SECONDS_REG,
 233                                  buf, sizeof(buf));
 234 }
 235
 236 static int ds1343_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 237 {
 238         struct ds1343_priv *priv = dev_get_drvdata(dev);
 239         unsigned char buf[4];
 240         unsigned int val;
 241         int res;
 242
 243         if (priv->irq <= 0)
 244                 return -EINVAL;
 245
 246         res = regmap_read(priv->map, DS1343_STATUS_REG, &val);
 247         if (res)
 248                 return res;
 249
 250         alarm->pending = !!(val & DS1343_IRQF0);
 251
 252         res = regmap_read(priv->map, DS1343_CONTROL_REG, &val);
 253         if (res)
 254                 return res;
 255         alarm->enabled = !!(val & DS1343_A0IE);
 256
 257         res = regmap_bulk_read(priv->map, DS1343_ALM0_SEC_REG, buf, 4);
 258         if (res)
 259                 return res;
 260
 261         alarm->time.tm_sec = bcd2bin(buf[0]) & 0x7f;
 262         alarm->time.tm_min = bcd2bin(buf[1]) & 0x7f;
 263         alarm->time.tm_hour = bcd2bin(buf[2]) & 0x3f;
 264         alarm->time.tm_mday = bcd2bin(buf[3]) & 0x3f;
 265
 266         return 0;
 267 }
 268
 269 static int ds1343_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 270 {
 271         struct ds1343_priv *priv = dev_get_drvdata(dev);
 272         unsigned char buf[4];
 273         int res = 0;
 274
 275         if (priv->irq <= 0)
 276                 return -EINVAL;
 277
 278         res = regmap_update_bits(priv->map, DS1343_CONTROL_REG, DS1343_A0IE, 0);
 279         if (res)
 280                 return res;
 281
 282         buf[0] = bin2bcd(alarm->time.tm_sec);
 283         buf[1] = bin2bcd(alarm->time.tm_min);
 284         buf[2] = bin2bcd(alarm->time.tm_hour);
 285         buf[3] = bin2bcd(alarm->time.tm_mday);
 286
 287         res = regmap_bulk_write(priv->map, DS1343_ALM0_SEC_REG, buf, 4);
 288         if (res)
 289                 return res;
 290
 291         if (alarm->enabled)
 292                 res = regmap_update_bits(priv->map, DS1343_CONTROL_REG,
 293                                          DS1343_A0IE, DS1343_A0IE);
 294
 295         return res;
 296 }
 297
 298 static int ds1343_alarm_irq_enable(struct device *dev, unsigned int enabled)
 299 {
 300         struct ds1343_priv *priv = dev_get_drvdata(dev);
 301
 302         if (priv->irq <= 0)
 303                 return -EINVAL;
 304
 305         return regmap_update_bits(priv->map, DS1343_CONTROL_REG,
 306                                   DS1343_A0IE, enabled ? DS1343_A0IE : 0);
 307 }
 308
 309 static irqreturn_t ds1343_thread(int irq, void *dev_id)
 310 {
 311         struct ds1343_priv *priv = dev_id;
 312         unsigned int stat;
 313         int res = 0;
 314
 315         rtc_lock(priv->rtc);
 316
 317         res = regmap_read(priv->map, DS1343_STATUS_REG, &stat);
 318         if (res)
 319                 goto out;
 320
 321         if (stat & DS1343_IRQF0) {
 322                 stat &= ~DS1343_IRQF0;
 323                 regmap_write(priv->map, DS1343_STATUS_REG, stat);
 324
 325                 rtc_update_irq(priv->rtc, 1, RTC_AF | RTC_IRQF);
 326
 327                 regmap_update_bits(priv->map, DS1343_CONTROL_REG,
 328                                    DS1343_A0IE, 0);
 329         }
 330
 331 out:
 332         rtc_unlock(priv->rtc);
 333         return IRQ_HANDLED;
 334 }
 335
 336 static const struct rtc_class_ops ds1343_rtc_ops = {
 337         .read_time      = ds1343_read_time,
 338         .set_time       = ds1343_set_time,
 339         .read_alarm     = ds1343_read_alarm,
 340         .set_alarm      = ds1343_set_alarm,
 341         .alarm_irq_enable = ds1343_alarm_irq_enable,
 342 };
 343
 344 static int ds1343_probe(struct spi_device *spi)
 345 {
 346         struct ds1343_priv *priv;
 347         struct regmap_config config = { .reg_bits = 8, .val_bits = 8,
 348                                         .write_flag_mask = 0x80, };
 349         unsigned int data;
 350         int res;
 351         struct nvmem_config nvmem_cfg = {
 352                 .name = "ds1343-",
 353                 .word_size = 1,
 354                 .stride = 1,
 355                 .size = DS1343_NVRAM_LEN,
 356                 .reg_read = ds1343_nvram_read,
 357                 .reg_write = ds1343_nvram_write,
 358         };
 359
 360         priv = devm_kzalloc(&spi->dev, sizeof(struct ds1343_priv), GFP_KERNEL);
 361         if (!priv)
 362                 return -ENOMEM;
 363
 364         /* RTC DS1347 works in spi mode 3 and
 365          * its chip select is active high. Active high should be defined as
 366          * "inverse polarity" as GPIO-based chip selects can be logically
 367          * active high but inverted by the GPIO library.
 368          */
 369         spi->mode |= SPI_MODE_3;
 370         spi->mode ^= SPI_CS_HIGH;
 371         spi->bits_per_word = 8;
 372         res = spi_setup(spi);
 373         if (res)
 374                 return res;
 375
 376         spi_set_drvdata(spi, priv);
 377
 378         priv->map = devm_regmap_init_spi(spi, &config);
 379
 380         if (IS_ERR(priv->map)) {
 381                 dev_err(&spi->dev, "spi regmap init failed for rtc ds1343\n");
 382                 return PTR_ERR(priv->map);
 383         }
 384
 385         res = regmap_read(priv->map, DS1343_SECONDS_REG, &data);
 386         if (res)
 387                 return res;
 388
 389         regmap_read(priv->map, DS1343_CONTROL_REG, &data);
 390         data |= DS1343_INTCN;
 391         data &= ~(DS1343_EOSC | DS1343_A1IE | DS1343_A0IE);
 392         regmap_write(priv->map, DS1343_CONTROL_REG, data);
 393
 394         regmap_read(priv->map, DS1343_STATUS_REG, &data);
 395         data &= ~(DS1343_OSF | DS1343_IRQF1 | DS1343_IRQF0);
 396         regmap_write(priv->map, DS1343_STATUS_REG, data);
 397
 398         priv->rtc = devm_rtc_allocate_device(&spi->dev);
 399         if (IS_ERR(priv->rtc))
 400                 return PTR_ERR(priv->rtc);
 401
 402         priv->rtc->ops = &ds1343_rtc_ops;
 403         priv->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
 404         priv->rtc->range_max = RTC_TIMESTAMP_END_2099;
 405
 406         res = rtc_add_group(priv->rtc, &ds1343_attr_group);
 407         if (res)
 408                 dev_err(&spi->dev,
 409                         "unable to create sysfs entries for rtc ds1343\n");
 410
 411         res = devm_rtc_register_device(priv->rtc);
 412         if (res)
 413                 return res;
 414
 415         nvmem_cfg.priv = priv;
 416         devm_rtc_nvmem_register(priv->rtc, &nvmem_cfg);
 417
 418         priv->irq = spi->irq;
 419
 420         if (priv->irq >= 0) {
 421                 res = devm_request_threaded_irq(&spi->dev, spi->irq, NULL,
 422                                                 ds1343_thread, IRQF_ONESHOT,
 423                                                 "ds1343", priv);
 424                 if (res) {
 425                         priv->irq = -1;
 426                         dev_err(&spi->dev,
 427                                 "unable to request irq for rtc ds1343\n");
 428                 } else {
 429                         device_init_wakeup(&spi->dev, true);
 430                         dev_pm_set_wake_irq(&spi->dev, spi->irq);
 431                 }
 432         }
 433
 434         return 0;
 435 }
 436
 437 static int ds1343_remove(struct spi_device *spi)
 438 {
 439         dev_pm_clear_wake_irq(&spi->dev);
 440
 441         return 0;
 442 }
 443
 444 #ifdef CONFIG_PM_SLEEP
 445
 446 static int ds1343_suspend(struct device *dev)
 447 {
 448         struct spi_device *spi = to_spi_device(dev);
 449
 450         if (spi->irq >= 0 && device_may_wakeup(dev))
 451                 enable_irq_wake(spi->irq);
 452
 453         return 0;
 454 }
 455
 456 static int ds1343_resume(struct device *dev)
 457 {
 458         struct spi_device *spi = to_spi_device(dev);
 459
 460         if (spi->irq >= 0 && device_may_wakeup(dev))
 461                 disable_irq_wake(spi->irq);
 462
 463         return 0;
 464 }
 465
 466 #endif
 467
 468 static SIMPLE_DEV_PM_OPS(ds1343_pm, ds1343_suspend, ds1343_resume);
 469
 470 static struct spi_driver ds1343_driver = {
 471         .driver = {
 472                 .name = "ds1343",
 473                 .pm = &ds1343_pm,
 474         },
 475         .probe = ds1343_probe,
 476         .remove = ds1343_remove,
 477         .id_table = ds1343_id,
 478 };
 479
 480 module_spi_driver(ds1343_driver);
 481
 482 MODULE_DESCRIPTION("DS1343 RTC SPI Driver");
 483 MODULE_AUTHOR("Raghavendra Chandra Ganiga <ravi23ganiga@gmail.com>,"
 484                 "Ankur Srivastava <sankurece@gmail.com>");
 485 MODULE_LICENSE("GPL v2");