linux/drivers/rtc/rtc-pcf85363.c
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   1/*
   2 * drivers/rtc/rtc-pcf85363.c
   3 *
   4 * Driver for NXP PCF85363 real-time clock.
   5 *
   6 * Copyright (C) 2017 Eric Nelson
   7 *
   8 * This program is free software; you can redistribute it and/or modify
   9 * it under the terms of the GNU General Public License version 2 as
  10 * published by the Free Software Foundation.
  11 *
  12 * Based loosely on rtc-8583 by Russell King, Wolfram Sang and Juergen Beisert
  13 */
  14#include <linux/module.h>
  15#include <linux/i2c.h>
  16#include <linux/slab.h>
  17#include <linux/rtc.h>
  18#include <linux/init.h>
  19#include <linux/err.h>
  20#include <linux/errno.h>
  21#include <linux/bcd.h>
  22#include <linux/of.h>
  23#include <linux/of_device.h>
  24#include <linux/regmap.h>
  25
  26/*
  27 * Date/Time registers
  28 */
  29#define DT_100THS       0x00
  30#define DT_SECS         0x01
  31#define DT_MINUTES      0x02
  32#define DT_HOURS        0x03
  33#define DT_DAYS         0x04
  34#define DT_WEEKDAYS     0x05
  35#define DT_MONTHS       0x06
  36#define DT_YEARS        0x07
  37
  38/*
  39 * Alarm registers
  40 */
  41#define DT_SECOND_ALM1  0x08
  42#define DT_MINUTE_ALM1  0x09
  43#define DT_HOUR_ALM1    0x0a
  44#define DT_DAY_ALM1     0x0b
  45#define DT_MONTH_ALM1   0x0c
  46#define DT_MINUTE_ALM2  0x0d
  47#define DT_HOUR_ALM2    0x0e
  48#define DT_WEEKDAY_ALM2 0x0f
  49#define DT_ALARM_EN     0x10
  50
  51/*
  52 * Time stamp registers
  53 */
  54#define DT_TIMESTAMP1   0x11
  55#define DT_TIMESTAMP2   0x17
  56#define DT_TIMESTAMP3   0x1d
  57#define DT_TS_MODE      0x23
  58
  59/*
  60 * control registers
  61 */
  62#define CTRL_OFFSET     0x24
  63#define CTRL_OSCILLATOR 0x25
  64#define CTRL_BATTERY    0x26
  65#define CTRL_PIN_IO     0x27
  66#define CTRL_FUNCTION   0x28
  67#define CTRL_INTA_EN    0x29
  68#define CTRL_INTB_EN    0x2a
  69#define CTRL_FLAGS      0x2b
  70#define CTRL_RAMBYTE    0x2c
  71#define CTRL_WDOG       0x2d
  72#define CTRL_STOP_EN    0x2e
  73#define CTRL_RESETS     0x2f
  74#define CTRL_RAM        0x40
  75
  76#define ALRM_SEC_A1E    BIT(0)
  77#define ALRM_MIN_A1E    BIT(1)
  78#define ALRM_HR_A1E     BIT(2)
  79#define ALRM_DAY_A1E    BIT(3)
  80#define ALRM_MON_A1E    BIT(4)
  81#define ALRM_MIN_A2E    BIT(5)
  82#define ALRM_HR_A2E     BIT(6)
  83#define ALRM_DAY_A2E    BIT(7)
  84
  85#define INT_WDIE        BIT(0)
  86#define INT_BSIE        BIT(1)
  87#define INT_TSRIE       BIT(2)
  88#define INT_A2IE        BIT(3)
  89#define INT_A1IE        BIT(4)
  90#define INT_OIE         BIT(5)
  91#define INT_PIE         BIT(6)
  92#define INT_ILP         BIT(7)
  93
  94#define FLAGS_TSR1F     BIT(0)
  95#define FLAGS_TSR2F     BIT(1)
  96#define FLAGS_TSR3F     BIT(2)
  97#define FLAGS_BSF       BIT(3)
  98#define FLAGS_WDF       BIT(4)
  99#define FLAGS_A1F       BIT(5)
 100#define FLAGS_A2F       BIT(6)
 101#define FLAGS_PIF       BIT(7)
 102
 103#define PIN_IO_INTAPM   GENMASK(1, 0)
 104#define PIN_IO_INTA_CLK 0
 105#define PIN_IO_INTA_BAT 1
 106#define PIN_IO_INTA_OUT 2
 107#define PIN_IO_INTA_HIZ 3
 108
 109#define STOP_EN_STOP    BIT(0)
 110
 111#define RESET_CPR       0xa4
 112
 113#define NVRAM_SIZE      0x40
 114
 115static struct i2c_driver pcf85363_driver;
 116
 117struct pcf85363 {
 118        struct device           *dev;
 119        struct rtc_device       *rtc;
 120        struct regmap           *regmap;
 121};
 122
 123static int pcf85363_rtc_read_time(struct device *dev, struct rtc_time *tm)
 124{
 125        struct pcf85363 *pcf85363 = dev_get_drvdata(dev);
 126        unsigned char buf[DT_YEARS + 1];
 127        int ret, len = sizeof(buf);
 128
 129        /* read the RTC date and time registers all at once */
 130        ret = regmap_bulk_read(pcf85363->regmap, DT_100THS, buf, len);
 131        if (ret) {
 132                dev_err(dev, "%s: error %d\n", __func__, ret);
 133                return ret;
 134        }
 135
 136        tm->tm_year = bcd2bin(buf[DT_YEARS]);
 137        /* adjust for 1900 base of rtc_time */
 138        tm->tm_year += 100;
 139
 140        tm->tm_wday = buf[DT_WEEKDAYS] & 7;
 141        buf[DT_SECS] &= 0x7F;
 142        tm->tm_sec = bcd2bin(buf[DT_SECS]);
 143        buf[DT_MINUTES] &= 0x7F;
 144        tm->tm_min = bcd2bin(buf[DT_MINUTES]);
 145        tm->tm_hour = bcd2bin(buf[DT_HOURS]);
 146        tm->tm_mday = bcd2bin(buf[DT_DAYS]);
 147        tm->tm_mon = bcd2bin(buf[DT_MONTHS]) - 1;
 148
 149        return 0;
 150}
 151
 152static int pcf85363_rtc_set_time(struct device *dev, struct rtc_time *tm)
 153{
 154        struct pcf85363 *pcf85363 = dev_get_drvdata(dev);
 155        unsigned char tmp[11];
 156        unsigned char *buf = &tmp[2];
 157        int ret;
 158
 159        tmp[0] = STOP_EN_STOP;
 160        tmp[1] = RESET_CPR;
 161
 162        buf[DT_100THS] = 0;
 163        buf[DT_SECS] = bin2bcd(tm->tm_sec);
 164        buf[DT_MINUTES] = bin2bcd(tm->tm_min);
 165        buf[DT_HOURS] = bin2bcd(tm->tm_hour);
 166        buf[DT_DAYS] = bin2bcd(tm->tm_mday);
 167        buf[DT_WEEKDAYS] = tm->tm_wday;
 168        buf[DT_MONTHS] = bin2bcd(tm->tm_mon + 1);
 169        buf[DT_YEARS] = bin2bcd(tm->tm_year % 100);
 170
 171        ret = regmap_bulk_write(pcf85363->regmap, CTRL_STOP_EN,
 172                                tmp, sizeof(tmp));
 173        if (ret)
 174                return ret;
 175
 176        return regmap_write(pcf85363->regmap, CTRL_STOP_EN, 0);
 177}
 178
 179static int pcf85363_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 180{
 181        struct pcf85363 *pcf85363 = dev_get_drvdata(dev);
 182        unsigned char buf[DT_MONTH_ALM1 - DT_SECOND_ALM1 + 1];
 183        unsigned int val;
 184        int ret;
 185
 186        ret = regmap_bulk_read(pcf85363->regmap, DT_SECOND_ALM1, buf,
 187                               sizeof(buf));
 188        if (ret)
 189                return ret;
 190
 191        alrm->time.tm_sec = bcd2bin(buf[0]);
 192        alrm->time.tm_min = bcd2bin(buf[1]);
 193        alrm->time.tm_hour = bcd2bin(buf[2]);
 194        alrm->time.tm_mday = bcd2bin(buf[3]);
 195        alrm->time.tm_mon = bcd2bin(buf[4]) - 1;
 196
 197        ret = regmap_read(pcf85363->regmap, CTRL_INTA_EN, &val);
 198        if (ret)
 199                return ret;
 200
 201        alrm->enabled =  !!(val & INT_A1IE);
 202
 203        return 0;
 204}
 205
 206static int _pcf85363_rtc_alarm_irq_enable(struct pcf85363 *pcf85363, unsigned
 207                                          int enabled)
 208{
 209        unsigned int alarm_flags = ALRM_SEC_A1E | ALRM_MIN_A1E | ALRM_HR_A1E |
 210                                   ALRM_DAY_A1E | ALRM_MON_A1E;
 211        int ret;
 212
 213        ret = regmap_update_bits(pcf85363->regmap, DT_ALARM_EN, alarm_flags,
 214                                 enabled ? alarm_flags : 0);
 215        if (ret)
 216                return ret;
 217
 218        ret = regmap_update_bits(pcf85363->regmap, CTRL_INTA_EN,
 219                                 INT_A1IE, enabled ? INT_A1IE : 0);
 220
 221        if (ret || enabled)
 222                return ret;
 223
 224        /* clear current flags */
 225        return regmap_update_bits(pcf85363->regmap, CTRL_FLAGS, FLAGS_A1F, 0);
 226}
 227
 228static int pcf85363_rtc_alarm_irq_enable(struct device *dev,
 229                                         unsigned int enabled)
 230{
 231        struct pcf85363 *pcf85363 = dev_get_drvdata(dev);
 232
 233        return _pcf85363_rtc_alarm_irq_enable(pcf85363, enabled);
 234}
 235
 236static int pcf85363_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 237{
 238        struct pcf85363 *pcf85363 = dev_get_drvdata(dev);
 239        unsigned char buf[DT_MONTH_ALM1 - DT_SECOND_ALM1 + 1];
 240        int ret;
 241
 242        buf[0] = bin2bcd(alrm->time.tm_sec);
 243        buf[1] = bin2bcd(alrm->time.tm_min);
 244        buf[2] = bin2bcd(alrm->time.tm_hour);
 245        buf[3] = bin2bcd(alrm->time.tm_mday);
 246        buf[4] = bin2bcd(alrm->time.tm_mon + 1);
 247
 248        /*
 249         * Disable the alarm interrupt before changing the value to avoid
 250         * spurious interrupts
 251         */
 252        ret = _pcf85363_rtc_alarm_irq_enable(pcf85363, 0);
 253        if (ret)
 254                return ret;
 255
 256        ret = regmap_bulk_write(pcf85363->regmap, DT_SECOND_ALM1, buf,
 257                                sizeof(buf));
 258        if (ret)
 259                return ret;
 260
 261        return _pcf85363_rtc_alarm_irq_enable(pcf85363, alrm->enabled);
 262}
 263
 264static irqreturn_t pcf85363_rtc_handle_irq(int irq, void *dev_id)
 265{
 266        struct pcf85363 *pcf85363 = i2c_get_clientdata(dev_id);
 267        unsigned int flags;
 268        int err;
 269
 270        err = regmap_read(pcf85363->regmap, CTRL_FLAGS, &flags);
 271        if (err)
 272                return IRQ_NONE;
 273
 274        if (flags & FLAGS_A1F) {
 275                rtc_update_irq(pcf85363->rtc, 1, RTC_IRQF | RTC_AF);
 276                regmap_update_bits(pcf85363->regmap, CTRL_FLAGS, FLAGS_A1F, 0);
 277                return IRQ_HANDLED;
 278        }
 279
 280        return IRQ_NONE;
 281}
 282
 283static const struct rtc_class_ops rtc_ops = {
 284        .read_time      = pcf85363_rtc_read_time,
 285        .set_time       = pcf85363_rtc_set_time,
 286};
 287
 288static const struct rtc_class_ops rtc_ops_alarm = {
 289        .read_time      = pcf85363_rtc_read_time,
 290        .set_time       = pcf85363_rtc_set_time,
 291        .read_alarm     = pcf85363_rtc_read_alarm,
 292        .set_alarm      = pcf85363_rtc_set_alarm,
 293        .alarm_irq_enable = pcf85363_rtc_alarm_irq_enable,
 294};
 295
 296static int pcf85363_nvram_read(void *priv, unsigned int offset, void *val,
 297                               size_t bytes)
 298{
 299        struct pcf85363 *pcf85363 = priv;
 300
 301        return regmap_bulk_read(pcf85363->regmap, CTRL_RAM + offset,
 302                                val, bytes);
 303}
 304
 305static int pcf85363_nvram_write(void *priv, unsigned int offset, void *val,
 306                                size_t bytes)
 307{
 308        struct pcf85363 *pcf85363 = priv;
 309
 310        return regmap_bulk_write(pcf85363->regmap, CTRL_RAM + offset,
 311                                 val, bytes);
 312}
 313
 314static const struct regmap_config regmap_config = {
 315        .reg_bits = 8,
 316        .val_bits = 8,
 317        .max_register = 0x7f,
 318};
 319
 320static int pcf85363_probe(struct i2c_client *client,
 321                          const struct i2c_device_id *id)
 322{
 323        struct pcf85363 *pcf85363;
 324        struct nvmem_config nvmem_cfg = {
 325                .name = "pcf85363-",
 326                .word_size = 1,
 327                .stride = 1,
 328                .size = NVRAM_SIZE,
 329                .reg_read = pcf85363_nvram_read,
 330                .reg_write = pcf85363_nvram_write,
 331        };
 332        int ret;
 333
 334        if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
 335                return -ENODEV;
 336
 337        pcf85363 = devm_kzalloc(&client->dev, sizeof(struct pcf85363),
 338                                GFP_KERNEL);
 339        if (!pcf85363)
 340                return -ENOMEM;
 341
 342        pcf85363->regmap = devm_regmap_init_i2c(client, &regmap_config);
 343        if (IS_ERR(pcf85363->regmap)) {
 344                dev_err(&client->dev, "regmap allocation failed\n");
 345                return PTR_ERR(pcf85363->regmap);
 346        }
 347
 348        pcf85363->dev = &client->dev;
 349        i2c_set_clientdata(client, pcf85363);
 350
 351        pcf85363->rtc = devm_rtc_allocate_device(pcf85363->dev);
 352        if (IS_ERR(pcf85363->rtc))
 353                return PTR_ERR(pcf85363->rtc);
 354
 355        pcf85363->rtc->ops = &rtc_ops;
 356
 357        if (client->irq > 0) {
 358                regmap_write(pcf85363->regmap, CTRL_FLAGS, 0);
 359                regmap_update_bits(pcf85363->regmap, CTRL_PIN_IO,
 360                                   PIN_IO_INTA_OUT, PIN_IO_INTAPM);
 361                ret = devm_request_threaded_irq(pcf85363->dev, client->irq,
 362                                                NULL, pcf85363_rtc_handle_irq,
 363                                                IRQF_TRIGGER_LOW | IRQF_ONESHOT,
 364                                                "pcf85363", client);
 365                if (ret)
 366                        dev_warn(&client->dev, "unable to request IRQ, alarms disabled\n");
 367                else
 368                        pcf85363->rtc->ops = &rtc_ops_alarm;
 369        }
 370
 371        ret = rtc_register_device(pcf85363->rtc);
 372
 373        nvmem_cfg.priv = pcf85363;
 374        rtc_nvmem_register(pcf85363->rtc, &nvmem_cfg);
 375
 376        return ret;
 377}
 378
 379static const struct of_device_id dev_ids[] = {
 380        { .compatible = "nxp,pcf85363" },
 381        {}
 382};
 383MODULE_DEVICE_TABLE(of, dev_ids);
 384
 385static struct i2c_driver pcf85363_driver = {
 386        .driver = {
 387                .name   = "pcf85363",
 388                .of_match_table = of_match_ptr(dev_ids),
 389        },
 390        .probe  = pcf85363_probe,
 391};
 392
 393module_i2c_driver(pcf85363_driver);
 394
 395MODULE_AUTHOR("Eric Nelson");
 396MODULE_DESCRIPTION("pcf85363 I2C RTC driver");
 397MODULE_LICENSE("GPL");
 398