linux/drivers/rtc/rtc-ds1343.c
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   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
  70static const struct spi_device_id ds1343_id[] = {
  71        { "ds1343", DALLAS_MAXIM_DS1343 },
  72        { "ds1344", DALLAS_MAXIM_DS1344 },
  73        { }
  74};
  75MODULE_DEVICE_TABLE(spi, ds1343_id);
  76
  77struct ds1343_priv {
  78        struct rtc_device *rtc;
  79        struct regmap *map;
  80        int irq;
  81};
  82
  83static 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
 102static 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
 123static DEVICE_ATTR(glitch_filter, S_IRUGO | S_IWUSR, ds1343_show_glitchfilter,
 124                        ds1343_store_glitchfilter);
 125
 126static 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
 134static 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
 142static 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
 186static DEVICE_ATTR(trickle_charger, S_IRUGO, ds1343_show_tricklecharger, NULL);
 187
 188static struct attribute *ds1343_attrs[] = {
 189        &dev_attr_glitch_filter.attr,
 190        &dev_attr_trickle_charger.attr,
 191        NULL
 192};
 193
 194static const struct attribute_group ds1343_attr_group = {
 195        .attrs  = ds1343_attrs,
 196};
 197
 198static 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
 219static 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
 236static 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
 269static 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
 298static 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
 309static 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
 331out:
 332        rtc_unlock(priv->rtc);
 333        return IRQ_HANDLED;
 334}
 335
 336static 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
 344static 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
 437static 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
 446static 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
 456static 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
 468static SIMPLE_DEV_PM_OPS(ds1343_pm, ds1343_suspend, ds1343_resume);
 469
 470static 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
 480module_spi_driver(ds1343_driver);
 481
 482MODULE_DESCRIPTION("DS1343 RTC SPI Driver");
 483MODULE_AUTHOR("Raghavendra Chandra Ganiga <ravi23ganiga@gmail.com>,"
 484                "Ankur Srivastava <sankurece@gmail.com>");
 485MODULE_LICENSE("GPL v2");
 486