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 spi_device *spi;
  79         struct rtc_device *rtc;
  80         struct regmap *map;
  81         int irq;
  82 };
  83
  84 static ssize_t ds1343_show_glitchfilter(struct device *dev,
  85                                 struct device_attribute *attr, char *buf)
  86 {
  87         struct ds1343_priv *priv = dev_get_drvdata(dev->parent);
  88         int glitch_filt_status, data;
  89         int res;
  90
  91         res = regmap_read(priv->map, DS1343_CONTROL_REG, &data);
  92         if (res)
  93                 return res;
  94
  95         glitch_filt_status = !!(data & DS1343_EGFIL);
  96
  97         if (glitch_filt_status)
  98                 return sprintf(buf, "enabled\n");
  99         else
 100                 return sprintf(buf, "disabled\n");
 101 }
 102
 103 static ssize_t ds1343_store_glitchfilter(struct device *dev,
 104                                         struct device_attribute *attr,
 105                                         const char *buf, size_t count)
 106 {
 107         struct ds1343_priv *priv = dev_get_drvdata(dev->parent);
 108         int data = 0;
 109         int res;
 110
 111         if (strncmp(buf, "enabled", 7) == 0)
 112                 data = DS1343_EGFIL;
 113         else if (strncmp(buf, "disabled", 8))
 114                 return -EINVAL;
 115
 116         res = regmap_update_bits(priv->map, DS1343_CONTROL_REG,
 117                                  DS1343_EGFIL, data);
 118         if (res)
 119                 return res;
 120
 121         return count;
 122 }
 123
 124 static DEVICE_ATTR(glitch_filter, S_IRUGO | S_IWUSR, ds1343_show_glitchfilter,
 125                         ds1343_store_glitchfilter);
 126
 127 static int ds1343_nvram_write(void *priv, unsigned int off, void *val,
 128                               size_t bytes)
 129 {
 130         struct ds1343_priv *ds1343 = priv;
 131
 132         return regmap_bulk_write(ds1343->map, DS1343_NVRAM + off, val, bytes);
 133 }
 134
 135 static int ds1343_nvram_read(void *priv, unsigned int off, void *val,
 136                              size_t bytes)
 137 {
 138         struct ds1343_priv *ds1343 = priv;
 139
 140         return regmap_bulk_read(ds1343->map, DS1343_NVRAM + off, val, bytes);
 141 }
 142
 143 static ssize_t ds1343_show_tricklecharger(struct device *dev,
 144                                 struct device_attribute *attr, char *buf)
 145 {
 146         struct ds1343_priv *priv = dev_get_drvdata(dev->parent);
 147         int res, data;
 148         char *diodes = "disabled", *resistors = " ";
 149
 150         res = regmap_read(priv->map, DS1343_TRICKLE_REG, &data);
 151         if (res)
 152                 return res;
 153
 154         if ((data & 0xf0) == DS1343_TRICKLE_MAGIC) {
 155                 switch (data & 0x0c) {
 156                 case DS1343_TRICKLE_DS1:
 157                         diodes = "one diode,";
 158                         break;
 159
 160                 default:
 161                         diodes = "no diode,";
 162                         break;
 163                 }
 164
 165                 switch (data & 0x03) {
 166                 case DS1343_TRICKLE_1K:
 167                         resistors = "1k Ohm";
 168                         break;
 169
 170                 case DS1343_TRICKLE_2K:
 171                         resistors = "2k Ohm";
 172                         break;
 173
 174                 case DS1343_TRICKLE_4K:
 175                         resistors = "4k Ohm";
 176                         break;
 177
 178                 default:
 179                         diodes = "disabled";
 180                         break;
 181                 }
 182         }
 183
 184         return sprintf(buf, "%s %s\n", diodes, resistors);
 185 }
 186
 187 static DEVICE_ATTR(trickle_charger, S_IRUGO, ds1343_show_tricklecharger, NULL);
 188
 189 static struct attribute *ds1343_attrs[] = {
 190         &dev_attr_glitch_filter.attr,
 191         &dev_attr_trickle_charger.attr,
 192         NULL
 193 };
 194
 195 static const struct attribute_group ds1343_attr_group = {
 196         .attrs  = ds1343_attrs,
 197 };
 198
 199 static int ds1343_read_time(struct device *dev, struct rtc_time *dt)
 200 {
 201         struct ds1343_priv *priv = dev_get_drvdata(dev);
 202         unsigned char buf[7];
 203         int res;
 204
 205         res = regmap_bulk_read(priv->map, DS1343_SECONDS_REG, buf, 7);
 206         if (res)
 207                 return res;
 208
 209         dt->tm_sec      = bcd2bin(buf[0]);
 210         dt->tm_min      = bcd2bin(buf[1]);
 211         dt->tm_hour     = bcd2bin(buf[2] & 0x3F);
 212         dt->tm_wday     = bcd2bin(buf[3]) - 1;
 213         dt->tm_mday     = bcd2bin(buf[4]);
 214         dt->tm_mon      = bcd2bin(buf[5] & 0x1F) - 1;
 215         dt->tm_year     = bcd2bin(buf[6]) + 100; /* year offset from 1900 */
 216
 217         return 0;
 218 }
 219
 220 static int ds1343_set_time(struct device *dev, struct rtc_time *dt)
 221 {
 222         struct ds1343_priv *priv = dev_get_drvdata(dev);
 223         u8 buf[7];
 224
 225         buf[0] = bin2bcd(dt->tm_sec);
 226         buf[1] = bin2bcd(dt->tm_min);
 227         buf[2] = bin2bcd(dt->tm_hour) & 0x3F;
 228         buf[3] = bin2bcd(dt->tm_wday + 1);
 229         buf[4] = bin2bcd(dt->tm_mday);
 230         buf[5] = bin2bcd(dt->tm_mon + 1);
 231         buf[6] = bin2bcd(dt->tm_year - 100);
 232
 233         return regmap_bulk_write(priv->map, DS1343_SECONDS_REG,
 234                                  buf, sizeof(buf));
 235 }
 236
 237 static int ds1343_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 238 {
 239         struct ds1343_priv *priv = dev_get_drvdata(dev);
 240         unsigned char buf[4];
 241         unsigned int val;
 242         int res;
 243
 244         if (priv->irq <= 0)
 245                 return -EINVAL;
 246
 247         res = regmap_read(priv->map, DS1343_STATUS_REG, &val);
 248         if (res)
 249                 return res;
 250
 251         alarm->pending = !!(val & DS1343_IRQF0);
 252
 253         res = regmap_read(priv->map, DS1343_CONTROL_REG, &val);
 254         if (res)
 255                 return res;
 256         alarm->enabled = !!(val & DS1343_A0IE);
 257
 258         res = regmap_bulk_read(priv->map, DS1343_ALM0_SEC_REG, buf, 4);
 259         if (res)
 260                 return res;
 261
 262         alarm->time.tm_sec = bcd2bin(buf[0]) & 0x7f;
 263         alarm->time.tm_min = bcd2bin(buf[1]) & 0x7f;
 264         alarm->time.tm_hour = bcd2bin(buf[2]) & 0x3f;
 265         alarm->time.tm_mday = bcd2bin(buf[3]) & 0x3f;
 266
 267         return 0;
 268 }
 269
 270 static int ds1343_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
 271 {
 272         struct ds1343_priv *priv = dev_get_drvdata(dev);
 273         unsigned char buf[4];
 274         int res = 0;
 275
 276         if (priv->irq <= 0)
 277                 return -EINVAL;
 278
 279         res = regmap_update_bits(priv->map, DS1343_CONTROL_REG, DS1343_A0IE, 0);
 280         if (res)
 281                 return res;
 282
 283         buf[0] = bin2bcd(alarm->time.tm_sec);
 284         buf[1] = bin2bcd(alarm->time.tm_min);
 285         buf[2] = bin2bcd(alarm->time.tm_hour);
 286         buf[3] = bin2bcd(alarm->time.tm_mday);
 287
 288         res = regmap_bulk_write(priv->map, DS1343_ALM0_SEC_REG, buf, 4);
 289         if (res)
 290                 return res;
 291
 292         if (alarm->enabled)
 293                 res = regmap_update_bits(priv->map, DS1343_CONTROL_REG,
 294                                          DS1343_A0IE, DS1343_A0IE);
 295
 296         return res;
 297 }
 298
 299 static int ds1343_alarm_irq_enable(struct device *dev, unsigned int enabled)
 300 {
 301         struct ds1343_priv *priv = dev_get_drvdata(dev);
 302
 303         if (priv->irq <= 0)
 304                 return -EINVAL;
 305
 306         return regmap_update_bits(priv->map, DS1343_CONTROL_REG,
 307                                   DS1343_A0IE, enabled ? DS1343_A0IE : 0);
 308 }
 309
 310 static irqreturn_t ds1343_thread(int irq, void *dev_id)
 311 {
 312         struct ds1343_priv *priv = dev_id;
 313         unsigned int stat;
 314         int res = 0;
 315
 316         rtc_lock(priv->rtc);
 317
 318         res = regmap_read(priv->map, DS1343_STATUS_REG, &stat);
 319         if (res)
 320                 goto out;
 321
 322         if (stat & DS1343_IRQF0) {
 323                 stat &= ~DS1343_IRQF0;
 324                 regmap_write(priv->map, DS1343_STATUS_REG, stat);
 325
 326                 rtc_update_irq(priv->rtc, 1, RTC_AF | RTC_IRQF);
 327
 328                 regmap_update_bits(priv->map, DS1343_CONTROL_REG,
 329                                    DS1343_A0IE, 0);
 330         }
 331
 332 out:
 333         rtc_unlock(priv->rtc);
 334         return IRQ_HANDLED;
 335 }
 336
 337 static const struct rtc_class_ops ds1343_rtc_ops = {
 338         .read_time      = ds1343_read_time,
 339         .set_time       = ds1343_set_time,
 340         .read_alarm     = ds1343_read_alarm,
 341         .set_alarm      = ds1343_set_alarm,
 342         .alarm_irq_enable = ds1343_alarm_irq_enable,
 343 };
 344
 345 static int ds1343_probe(struct spi_device *spi)
 346 {
 347         struct ds1343_priv *priv;
 348         struct regmap_config config = { .reg_bits = 8, .val_bits = 8,
 349                                         .write_flag_mask = 0x80, };
 350         unsigned int data;
 351         int res;
 352         struct nvmem_config nvmem_cfg = {
 353                 .name = "ds1343-",
 354                 .word_size = 1,
 355                 .stride = 1,
 356                 .size = DS1343_NVRAM_LEN,
 357                 .reg_read = ds1343_nvram_read,
 358                 .reg_write = ds1343_nvram_write,
 359         };
 360
 361         priv = devm_kzalloc(&spi->dev, sizeof(struct ds1343_priv), GFP_KERNEL);
 362         if (!priv)
 363                 return -ENOMEM;
 364
 365         priv->spi = spi;
 366
 367         /* RTC DS1347 works in spi mode 3 and
 368          * its chip select is active high
 369          */
 370         spi->mode = SPI_MODE_3 | 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->nvram_old_abi = true;
 403         priv->rtc->ops = &ds1343_rtc_ops;
 404         priv->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
 405         priv->rtc->range_max = RTC_TIMESTAMP_END_2099;
 406
 407         res = rtc_add_group(priv->rtc, &ds1343_attr_group);
 408         if (res)
 409                 dev_err(&spi->dev,
 410                         "unable to create sysfs entries for rtc ds1343\n");
 411
 412         res = rtc_register_device(priv->rtc);
 413         if (res)
 414                 return res;
 415
 416         nvmem_cfg.priv = priv;
 417         rtc_nvmem_register(priv->rtc, &nvmem_cfg);
 418
 419         priv->irq = spi->irq;
 420
 421         if (priv->irq >= 0) {
 422                 res = devm_request_threaded_irq(&spi->dev, spi->irq, NULL,
 423                                                 ds1343_thread, IRQF_ONESHOT,
 424                                                 "ds1343", priv);
 425                 if (res) {
 426                         priv->irq = -1;
 427                         dev_err(&spi->dev,
 428                                 "unable to request irq for rtc ds1343\n");
 429                 } else {
 430                         device_init_wakeup(&spi->dev, true);
 431                         dev_pm_set_wake_irq(&spi->dev, spi->irq);
 432                 }
 433         }
 434
 435         return 0;
 436 }
 437
 438 static int ds1343_remove(struct spi_device *spi)
 439 {
 440         dev_pm_clear_wake_irq(&spi->dev);
 441
 442         return 0;
 443 }
 444
 445 #ifdef CONFIG_PM_SLEEP
 446
 447 static int ds1343_suspend(struct device *dev)
 448 {
 449         struct spi_device *spi = to_spi_device(dev);
 450
 451         if (spi->irq >= 0 && device_may_wakeup(dev))
 452                 enable_irq_wake(spi->irq);
 453
 454         return 0;
 455 }
 456
 457 static int ds1343_resume(struct device *dev)
 458 {
 459         struct spi_device *spi = to_spi_device(dev);
 460
 461         if (spi->irq >= 0 && device_may_wakeup(dev))
 462                 disable_irq_wake(spi->irq);
 463
 464         return 0;
 465 }
 466
 467 #endif
 468
 469 static SIMPLE_DEV_PM_OPS(ds1343_pm, ds1343_suspend, ds1343_resume);
 470
 471 static struct spi_driver ds1343_driver = {
 472         .driver = {
 473                 .name = "ds1343",
 474                 .pm = &ds1343_pm,
 475         },
 476         .probe = ds1343_probe,
 477         .remove = ds1343_remove,
 478         .id_table = ds1343_id,
 479 };
 480
 481 module_spi_driver(ds1343_driver);
 482
 483 MODULE_DESCRIPTION("DS1343 RTC SPI Driver");
 484 MODULE_AUTHOR("Raghavendra Chandra Ganiga <ravi23ganiga@gmail.com>,"
 485                 "Ankur Srivastava <sankurece@gmail.com>");
 486 MODULE_LICENSE("GPL v2");